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Sample records for pv inverter connected

  1. Design optimization of grid-connected PV inverters

    DEFF Research Database (Denmark)

    Koutroulis, Eftichios; Blaabjerg, Frede

    2011-01-01

    The DC/AC inverters are the key elements in grid-connected PV energy production systems. In this paper, new design optimization techniques focused on transformerless (very high efficiency) PV inverters are proposed. They have been developed based on an analysis of the deficiencies of the current......, state-of-the-art PV inverters design technology, which limits the amount of PV energy supplied into the electric grid. The influences of the electric grid regulations and standards and the PV array operational characteristics on the design of grid-connected PV inverters have also been considered....... The simulation results verify that the proposed optimization techniques enable the maximization of the PV energy injected into the electric grid by the optimized PV installation....

  2. Design Optimization of Transformerless Grid-Connected PV Inverters Including Reliability

    OpenAIRE

    Koutroulis, Eftichios; Blaabjerg, Frede

    2013-01-01

    This paper presents a new methodology for optimal design of transformerless photovoltaic (PV) inverters targeting a cost-effective deployment of grid-connected PV systems. The optimal switching frequency as well as the optimal values and types of the PV inverter components is calculated such that the PV inverter LCOE generated during the PV system lifetime period is minimized. The LCOE is also calculated considering the failure rates of the components, which affect the reliability performance...

  3. Design optimization of transformerless grid-connected PV inverters including reliability

    DEFF Research Database (Denmark)

    Koutroulis, Eftichios; Blaabjerg, Frede

    2012-01-01

    Of the Electricity (LCOE) generated during the PV system lifetime period is minimized. The LCOE is calculated also considering the failure rates of the components, which affect the reliability performance and lifetime maintenance cost of the PV inverter. A design example is presented, demonstrating that compared...... to the non-optimized PV inverter structures, the PV inverters designed using the proposed optimization methodology exhibit lower total manufacturing and lifetime maintenance cost and inject more energy into the electric-grid and by that minimizing LCOE.......This paper presents a new methodology for optimal design of transformerless Photovoltaic (PV) inverters targeting a cost-effective deployment of grid-connected PV systems. The optimal values and types of the PV inverter components are calculated such that the PV inverter Levelized Cost...

  4. Design Optimization of Transformerless Grid-Connected PV Inverters Including Reliability

    DEFF Research Database (Denmark)

    Koutroulis, Eftichios; Blaabjerg, Frede

    2013-01-01

    such that the PV inverter LCOE generated during the PV system lifetime period is minimized. The LCOE is also calculated considering the failure rates of the components, which affect the reliability performance and lifetime maintenance cost of the PV inverter. A design example is presented, demonstrating...... that compared to the nonoptimized PV inverter structures, the PV inverters designed using the proposed optimization methodology exhibit lower total manufacturing and lifetime maintenance cost and inject more energy into the electric-grid and by that minimizing LCOE.......This paper presents a new methodology for optimal design of transformerless photovoltaic (PV) inverters targeting a cost-effective deployment of grid-connected PV systems. The optimal switching frequency as well as the optimal values and types of the PV inverter components is calculated...

  5. Real Time Photovoltaic Array Simulator for Testing Grid-Connected PV Inverters

    DEFF Research Database (Denmark)

    Sera, Dezso; Valentini, Massimo; Raducu, Alin

    2008-01-01

    In this paper a real time flexible PV array simulator is presented. It is a system that can simulate different PV panel arrays in specific environmental conditions. To evaluate performance of the Maximum Power Point Tracking (MPPT) of grid-connected Photovoltaic (PV) inverters only measurements...... undertaken with an appropriate PV array simulator provide accurate and reproducible results. Thus the PV array simulator has been developed and implemented. MPPT efficiency tests on a commercial grid-connected PV inverter have been performed to validate the PV array simulator....

  6. Methods for the Optimal Design of Grid-Connected PV Inverters

    DEFF Research Database (Denmark)

    Koutroulis, Eftichios; Blaabjerg, Frede

    2011-01-01

    and the efficient processing of this power by the DC/AC inverter. In this paper two new methods are presented for the optimal design of a PV inverter power section, output filter and MPPT control strategy. The influences of the electric grid regulations and standards as well as the PV array operational......The DC/AC inverters are used in grid-connected PV energy production systems as the power processing interface between the PV energy source and the electric grid. The energy injected into the electric grid by the PV installation depends on the amount of power extracted from the PV power source...

  7. Modeling Single-Phase PV HB-ZVR Inverter Connected to Grid

    DEFF Research Database (Denmark)

    Guo, Yougui; Zeng, Ping; Zhu, Jieqiong

    2011-01-01

    PLECS is used to model the PV H-bridge zero voltage rectifier (HB-ZVR) inverter connected to grid and good results are obtained. First, several common topologies of PV inverters are introduced. Then the unipolar PWM control strategy is described for PV HB-ZVR inverter. Third, PLECS is briefly...... introduced. Fourth, the modeling of PV HB-ZVR inverter is presented with PLECS. Finally, a series of simulations are carried out. The simulation results tell us PLECS is very powerful tool to real power circuits and it is very easy to simulate LCL filter. They have also verified that the unipolar PWM control...... strategy is feasible to control the PV HB-ZVR inverter....

  8. Reliability Oriented Design Tool For the New Generation of Grid Connected PV-Inverters

    DEFF Research Database (Denmark)

    Sintamarean, Nicolae Cristian; Blaabjerg, Frede; Wang, Huai

    2015-01-01

    is achieved and is further used as an input to the lifetime model. The proposed reliability-oriented design tool is used to study the impact of mission profile (MP) variation and device degradation (aging) in the PV inverter lifetime. The obtained results indicate that the MP of the field where the PV...... inverter is operating has an important impact (up to 70%) on the converter lifetime expectation, and it should be considered in the design stage to better optimize the converter design margin. In order to have correct lifetime estimation, it is crucial to consider also the device degradation feedback (in......This paper introduces a reliability-oriented design tool for a new generation of grid-connected photovoltaic (PV) inverters. The proposed design tool consists of a real field mission profile (RFMP) model (for two operating regions: USA and Denmark), a PV panel model, a grid-connected PV inverter...

  9. A Direct Maximum Power Point Tracking Method for Single-Phase Grid Connected PV Inverters

    DEFF Research Database (Denmark)

    EL Aamri, Faicel; Maker, Hattab; Sera, Dezso

    2018-01-01

    in dynamic conditions, especially in low irradiance when the measurement of signals becomes more sensitive to noise. The proposed MPPT is designed for single-phase single-stage grid-connected PV inverters, and is based on estimating the instantaneous PV power and voltage ripples, using second...

  10. Delta Power Control Strategy for Multistring Grid-Connected PV Inverters

    DEFF Research Database (Denmark)

    Sangwongwanich, Ariya; Yang, Yongheng; Blaabjerg, Frede

    2017-01-01

    , is required for grid support (e.g., during frequency deviation). In this paper, a cost-effective solution to realize delta power control (DPC) for grid-connected PV systems is presented, where the multistring PV inverter configuration is adopted. This control strategy is a combination of maximum power point...... tracking (MPPT) and constant power generation (CPG) modes. In this control scheme, one PV string operating in the MPPT mode estimates the available power, whereas the other PV strings regulate the total PV power by the CPG control strategy in such a way that the delta power constraint for the entire PV...... system is achieved. Simulations and experiments have been performed on a 3-kW single-phase grid-connected PV system. The results have confirmed the effectiveness of the proposed DPC strategy, where the power reserve according to the delta power constraint is achieved under several operating conditions....

  11. Delta Power Control Strategy for Multi-String Grid-Connected PV Inverters

    DEFF Research Database (Denmark)

    Sangwongwanich, Ariya; Yang, Yongheng; Blaabjerg, Frede

    2016-01-01

    With a still increasing penetration level of grid-connected PV systems, more advanced active power control functionalities have been introduced in certain grid regulations. A delta power constraint, where a portion of the active power from the PV panels is reserved during operation, is required...... for grid support (e.g., during frequency deviation). In this paper, a cost-effective solution to realize delta power control for grid-connected PV systems is presented, where the residential/commercial multi-string PV inverter configuration is adopted. This control strategy is a combination of Maximum...... for the entire PV system is achieved. Simulations and experiments have been performed on a 3-kW single-phase grid-connected PV system. The results have confirmed the effectiveness of the delta power control strategy, where the power reserve according to the delta power constraint is achieved under several...

  12. An Optimal Current Controller Design for a Grid Connected Inverter to Improve Power Quality and Test Commercial PV Inverters.

    Science.gov (United States)

    Algaddafi, Ali; Altuwayjiri, Saud A; Ahmed, Oday A; Daho, Ibrahim

    2017-01-01

    Grid connected inverters play a crucial role in generating energy to be fed to the grid. A filter is commonly used to suppress the switching frequency harmonics produced by the inverter, this being passive, and either an L- or LCL-filter. The latter is smaller in size compared to the L-filter. But choosing the optimal values of the LCL-filter is challenging due to resonance, which can affect stability. This paper presents a simple inverter controller design with an L-filter. The control topology is simple and applied easily using traditional control theory. Fast Fourier Transform analysis is used to compare different grid connected inverter control topologies. The modelled grid connected inverter with the proposed controller complies with the IEEE-1547 standard, and total harmonic distortion of the output current of the modelled inverter has been just 0.25% with an improved output waveform. Experimental work on a commercial PV inverter is then presented, including the effect of strong and weak grid connection. Inverter effects on the resistive load connected at the point of common coupling are presented. Results show that the voltage and current of resistive load, when the grid is interrupted, are increased, which may cause failure or damage for connecting appliances.

  13. Adaptive fuzzy sliding control of single-phase PV grid-connected inverter.

    Science.gov (United States)

    Fei, Juntao; Zhu, Yunkai

    2017-01-01

    In this paper, an adaptive fuzzy sliding mode controller is proposed to control a two-stage single-phase photovoltaic (PV) grid-connected inverter. Two key technologies are discussed in the presented PV system. An incremental conductance method with adaptive step is adopted to track the maximum power point (MPP) by controlling the duty cycle of the controllable power switch of the boost DC-DC converter. An adaptive fuzzy sliding mode controller with an integral sliding surface is developed for the grid-connected inverter where a fuzzy system is used to approach the upper bound of the system nonlinearities. The proposed strategy has strong robustness for the sliding mode control can be designed independently and disturbances can be adaptively compensated. Simulation results of a PV grid-connected system verify the effectiveness of the proposed method, demonstrating the satisfactory robustness and performance.

  14. S4 Grid-Connected Single-Phase Transformerless Inverter for PV Application

    DEFF Research Database (Denmark)

    Ardashir, Jaber Fallah; Siwakoti, Yam Prasad; Sabahi, Mehran

    2016-01-01

    This paper introduces a new single-phase transformerless inverter for grid-connected photovoltaic systems with low leakage current. It consists of four power switches, two diodes, two capacitors and a filter at the output stage. The neutral of the grid is directly connected to the negative terminal...... size, low cost, flexible grounding configuration and higher efficiency. The operating principle and analysis of the proposed circuit are presented in details. Experimental results of a 500 W prototype are demonstrated to validate the proposed topology and the overall concept. The results obtained...... clearly verify the performance of the proposed inverter and its practical application for grid-connected PV systems....

  15. Lifetime Evaluation of Grid-Connected PV Inverters Considering Panel Degradation Rates and Installation Sites

    OpenAIRE

    Sangwongwanich, Ariya; Yang, Yongheng; Sera, Dezso; Blaabjerg, Frede

    2018-01-01

    Lifetime of PV inverters is affected by the installation sites related to different solar irradiance and ambient temperature profiles (also referred to as mission profiles). In fact, the installation site also affects the degradation rate of the PV panels, and thus long-term energy production and reliability. Prior-art lifetime analysis in PV inverters has not yet investigated the impact of PV panel degradations. This paper thus evaluates the lifetime of PV inverters considering panel degrada...

  16. Lifetime Evaluation of Grid-Connected PV Inverters Considering Panel Degradation Rates and Installation Sites

    DEFF Research Database (Denmark)

    Sangwongwanich, Ariya; Yang, Yongheng; Sera, Dezso

    2018-01-01

    Lifetime of PV inverters is affected by the installation sites related to different solar irradiance and ambient temperature profiles (also referred to as mission profiles). In fact, the installation site also affects the degradation rate of the PV panels, and thus long-term energy production...... and reliability. Prior-art lifetime analysis in PV inverters has not yet investigated the impact of PV panel degradations. This paper thus evaluates the lifetime of PV inverters considering panel degradation rates and mission profiles. Evaluations have been carried out on PV systems installed in Denmark...... and Arizona. The results reveal that the PV panel degradation rate has a considerable impact on the PV inverter lifetime, especially in the hot climate (e.g., Arizona), where the panel degrades at a faster rate. In that case, the PV inverter lifetime prediction can be deviated by 54%, if the impact of PV...

  17. Common mode voltage in case of transformerless PV inverters connected to the grid

    DEFF Research Database (Denmark)

    Kerekes, Tamas; Teodorescu, Remus; Liserre, Marco

    2008-01-01

    For safety reasons grid connected PV systems include galvanic isolation. In case of transformerless inverters, the leakage ground current through the parasitic capacitance of the PV panels, can reach very high values. A common-mode model based on analytical approach is introduced, used to predict...... the common-mode behavior, at frequencies lower than 50kHz, of the selected topologies and to explain the influence of system imbalance on the leakage current. It will be demonstrated that the neutral inductance has a crucial influence on the leakage current. Finally experimental results will be shown...

  18. Control and Modulation Techniques for a Centralized PV Generation System Grid Connected via an Interleaved Inverter

    Directory of Open Access Journals (Sweden)

    Gianluca Brando

    2016-09-01

    Full Text Available In the context of grid connected photovoitaic (PV generation systems, there are two paramount aspects regarding the Maximum Power Point Tracking (MPPT of the photovoltaic units and the continuity of the service. The most diffused MPPT algorithms are based on either perturb and observe, or on an incremental conductance approach and need both PV current and voltage measurements. Several topology reconfigurable converters are also associated with the PV plants, guaranteeing fault-tolerant features. The generation continuity can also be assured by interleaved inverters, which keep the system operating at reduced maximum power in case of failure. In this paper, an evolution of a hysteresis based MPPT algorithm is presented, based on the measurement of only one voltage, together with a novel space vector modulation suitable for a two-channel three-phase grid connected interleaved inverter. The proposed MMPT algorithm and modulation technique are tested by means of several numerical analyses on a PV generation system of about 200 kW maximum power. The results testify the validity of the proposed strategies, showing good performance, even during a fault occurrence and in the presence of deep shading conditions.

  19. Stability of Grid-Connected PV Inverters with Large Grid Impedance Variation

    DEFF Research Database (Denmark)

    Liserre, Marco; Teodorescu, Remus; Blaabjerg, Frede

    2004-01-01

    Photovoltaic (PV) inverters used in dispersed power generation of houses in the range of 1-5 kW are currently available from several manufactures. However, large grid impedance variation is challenging the control and the grid filter design in terms of stability. In fact the PV systems are well...... suited for loads connected in a great distance to the transformer (long wires) and the situation becomes even more difficult in low-developed remote areas characterized by low power transformers and long distribution wires with high grid impedance. Hence a theoretical analysis is needed because the grid...... impedance variation leads to dynamic and stability problems both in the low frequency range (around the current controller bandwidth frequency) as well as in the high frequency range (around the LCL-filter resonance frequency). In the low frequency range the possible variation of the impedance challenges...

  20. A Fuzzy Logic Based Three phase Inverter with Single DC Source for Grid Connected PV System Employing Three Phase Transformer

    OpenAIRE

    Mani, venkatesan; Ramachandran, Rajeswari; N, Deverajan

    2016-01-01

    A fuzzy based three phase inverter with single DC source for grid connected photo voltaic (PV) system employing three phase transformer is presented in this paper. Space Vector Pulse Width Modulation (SVPWM) control scheme is effectively used to generate the appropriate switching sequences to the inverter switches. The intend of the fuzzy logic approach is to meet high quality output, fast response and high robustness. Finally Total Harmonics Distortion (THD) generated by the inverter is comp...

  1. Supervision and control of grid connected PV-Storage systems with the five level diode clamped inverter

    International Nuclear Information System (INIS)

    Himour, Kamal; Ghedamsi, Kaci; Berkouk, El Madjid

    2014-01-01

    Highlights: • Use of battery bank in grid connection photovoltaic system to ensure the energetic autonomy of the system. • Improve the quality of energy by the use of five-level inverter in a grid connection PV generation system. • Control of inverter by fast and simplified space vector pulse width modulation. • Control and supervision of active and reactive power in the grid. - Abstract: This paper aimed to evaluate the use of photovoltaic-battery storage systems to supply electric power in the distribution grid through a multilevel inverter. The proposed system is composed by four PV generators with MPPT (P and O) control, four battery storage systems connected to each capacitor of the DC link and a five level diode clamped inverter connected to the grid by a traditional three phase transformer. The proposed control has a hierarchical structure with both a grid side control level to regulate the power and the current injected to the grid and four input side regulation units. The system operator controls the power production of the four PV generators by sending out reference power signals to each input side regulation unit, the input side regulation units regulate the voltage of each capacitor of the DC link, regulate the voltage and the state of charge of each battery storage system

  2. Advances in PV Inverters

    DEFF Research Database (Denmark)

    Anthon, Alexander

    and preferably low complexity leads to new research demands. This is especially true in the field of low cost residential PV inverters where efficiencies are used as major selling arguments. Traditional converter topologies equipped with conventional Silicon based semiconductors to date reach their limitations......, a replacement of only two switching devices per phase leg can greatly reduce the semiconductor losses. The Hybrid-NPC converter can be seen as an attractive and cost competitive alternative to the Silicon Carbide based converter, also allowing to overcome the major drawbacks with the conventional Silicon IGBT...

  3. Transformerless PV inverters. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Borup, U.

    2009-12-15

    Since the start of the project the market for grid connected PV inverters have developed further. When the project started three - phase inverter were only available in high power systems. The technology developed within this project will enable three phase technology also to be implemented in string inverters for system down to 10 kW. We expect this to be very attractive due to the increased demand for symmetrical feed-in to the grid. The project relevance is therefore high and the sector continues to develop very much driven by technology. Especially the inverter technology is getting a lot of focus. The inverter systems are expected to take a much larger role in supporting the electrical grid in the future. The technology platform developed within the project is prepared to be extended with these utility functionalities. The main results of the project were: 1) A new technology concept for transformer-less inverters has been demonstrated with a number of prototypes. 2) Efficiency above 97,7% has been proven. 3) Efficiency and Maximum power point tracking has been optimized to ensure that almost all energy produced of the panels is transferred to the grid. 4) The platform is developed with a very fast control board, which enables extended functionality as demanding grid supporting functions in the future. Details about cost price and details about the control loop implementation is excluded from the report due to the competitive situation for Danfoss Solar Inverters A/S. (LN)

  4. Leakage current analysis of a single-phase transformer-less PV inverter connected to the grid

    DEFF Research Database (Denmark)

    Ma, Lin; Tang, F.; Zhou, F.

    2009-01-01

    Due to the large surface of the PV generator, its stray capacity with respect to the ground reaches values that can be quite high. When no transformer is used in a grid-connected PV system, common-mode current, which caused by the common mode voltage, can flow through the stray capacitance between...... the PV array and the ground. It is quite harmful to the body safety and PV system. In order to avoid leakage current, different inverter topologies that generate no varying common-mode voltages, such as bipolar pulse-width modulation (PWM) full-bridge topology, NPC topology have been proposed. From...... the safety and energy saving viewpoint, it is necessary to develop a higher efficiency topology. In this paper, the generation mechanism of common mode current is discussed. Then different methods used to eliminate the leakage current are compared. Finally, the full-bridge which generates no varying common...

  5. Control Strategy for Three-Phase Grid-Connected PV Inverters Enabling Current Limitation Under Unbalanced Faults

    DEFF Research Database (Denmark)

    Afshari, Ehsan; Moradi, Gholam Reza; Rahimi, Ramin

    2017-01-01

    Power quality and voltage control are among the most important aspects of the grid-connected power converter operation under faults. Non-sinusoidal current is injected during unbalanced voltage sag and active or/and reactive power includes double frequency content. This paper introduces a novel...... control strategy to mitigate the double grid frequency oscillations in the active power and dc-link voltage of the two-stage three-phase grid-connected Photovoltaic (PV) inverters during unbalanced faults. With the proposed control method, PV inverter injects sinusoidal currents under unbalanced grid...... faults. In addition, an efficient and easy-to-implement current limitation method is introduced, which can effectively limit the injected currents to the rated value during faults. In this case, the fault-ride-through operation is ensured and it will not trigger the overcurrent protection. A non...

  6. Leakage current analysis of single-phase transformer-less grid-connected PV inverters

    DEFF Research Database (Denmark)

    Ma, Lin; Kerekes, Tamas; Teodorescu, Remus

    2016-01-01

    Transformer-less string PV inverter is getting more and more widely utilized due to its higher efficiency, smaller volume and weight. However, without the galvanic isolation, the leakage current limitation and operation safety became the key issues of transformer-less inverters. This paper...... simplifies the leakage current generation circuit model and presents a leakage current estimation method both in real time and frequency domain. It shows that the leakage current is related to the circuit stray parameters, output filter and common mode voltage. Furthermore, with the proposed analysis method......, the leakage current generation of H-bridge with different modulation methods and HERIC inverter are discussed individually. At last, the presented method has been verified via simulation....

  7. Study on model current predictive control method of PV grid- connected inverters systems with voltage sag

    Science.gov (United States)

    Jin, N.; Yang, F.; Shang, S. Y.; Tao, T.; Liu, J. S.

    2016-08-01

    According to the limitations of the LVRT technology of traditional photovoltaic inverter existed, this paper proposes a low voltage ride through (LVRT) control method based on model current predictive control (MCPC). This method can effectively improve the photovoltaic inverter output characteristics and response speed. The MCPC method of photovoltaic grid-connected inverter designed, the sum of the absolute value of the predictive current and the given current error is adopted as the cost function with the model predictive control method. According to the MCPC, the optimal space voltage vector is selected. Photovoltaic inverter has achieved automatically switches of priority active or reactive power control of two control modes according to the different operating states, which effectively improve the inverter capability of LVRT. The simulation and experimental results proves that the proposed method is correct and effective.

  8. Lyapunov-Based Control Scheme for Single-Phase Grid-Connected PV Central Inverters

    NARCIS (Netherlands)

    Meza, C.; Biel, D.; Jeltsema, D.; Scherpen, J. M. A.

    A Lyapunov-based control scheme for single-phase single-stage grid-connected photovoltaic central inverters is presented. Besides rendering the closed-loop system globally stable, the designed controller is able to deal with the system uncertainty that depends on the solar irradiance. A laboratory

  9. LVRT Capability of Single-Phase Grid-Connected HERIC Inverter in PV Systems by a Look-up Table Based Predictive Control

    DEFF Research Database (Denmark)

    Zangeneh Bighash, Esmaeil; Sadeghzadeh, Seyed Mohammad; Ebrahimzadeh, Esmaeil

    2017-01-01

    Nowadays capacity of the photovoltaic systems in the grid is remarkable and provides a major part of energy in the grid. Therefore, an abruption of these systems from the grid can create a damage to the grid. Unlike in the past that PV systems disconnected from the grid when a voltage drop occurred......, nowadays these systems should have Low Voltage Ride-Through (LVRT) capability. The PV system should stay connected to the grid at fault time and help to recover the grid voltage by injecting the reactive power like in a power plant or a custom power device. There are two important factors for single phase...... grid connected PV inverters. The first one is the structure of the inverter and the second one is the control part. In this regard, the HERIC inverter can be a good selection among the transformerless inverters for a PV system due to its high efficiency. For the control part, this paper presents a look...

  10. MPPT algorithm for voltage controlled PV inverters

    DEFF Research Database (Denmark)

    Kerekes, Tamas; Teodorescu, Remus; Liserre, Marco

    2008-01-01

    This paper presents a novel concept for an MPPT that can be used in case of a voltage controlled grid connected PV inverters. In case of single-phase systems, the 100 Hz ripple in the AC power is also present on the DC side. Depending on the DC link capacitor, this power fluctuation can be used t...... to track the MPP of the PV array, using the information that at MPP the power oscillations are very small. In this way the algorithm can detect the fact that the current working point is at the MPP, for the current atmospheric conditions....

  11. Grid-Connection Half-Bridge PV Inverter System for Power Flow Controlling and Active Power Filtering

    Directory of Open Access Journals (Sweden)

    Chih-Lung Shen

    2012-01-01

    Full Text Available A half-bridge photovoltaic (PV system is proposed, which can not only deal with bidirectional power flowing but also improve power quality. According to varying insolation, the system conditions real power for dc and ac loads to accommodate different amounts of PV power. Furthermore, the system eliminates current harmonics and improves power factor simultaneously. As compared with conventional PV inverter, the total number of active switches and current sensors can be reduced so that its cost is lower significantly. For current command determination, a linear-approximation method (LAM is applied to avoid the complicated calculation and achieve the maximum power point tracking (MPPT feature. For current controlling, a direct-source-current-shaping (DSCS algorithm is presented to shape the waveform of line current. Simulation results and practical measurements also demonstrate the feasibility of the proposed half-bridge PV system.

  12. Robustness analysis of the efficiency in PV inverters

    DEFF Research Database (Denmark)

    Pigazo, Alberto; Liserre, Marco; Blaabjerg, Frede

    2013-01-01

    topology and control strategy but also on the characteristics of the employed components. The aim of this paper is evaluate the effect of physical variations associated to the main components on the overall efficiency of PV inverters. It is concluded that a statistical evaluation of the power converter......During last years an increasing attention has been paid to the efficiency of grid-connected PV inverters. They are manufactured from a number of discrete components and by using a certain topology and control strategy. Hence, the performance of a certain PV inverter not only depends on the selected...

  13. Modeling, numerical simulation, and nonlinear dynamic behavior analysis of PV microgrid-connected inverter with capacitance catastrophe

    Science.gov (United States)

    Li, Sichen; Liao, Zhixian; Luo, Xiaoshu; Wei, Duqu; Jiang, Pinqun; Jiang, Qinghong

    2018-02-01

    The value of the output capacitance (C) should be carefully considered when designing a photovoltaic (PV) inverter since it can cause distortion in the working state of the circuit, and the circuit produces nonlinear dynamic behavior. According to Kirchhoff’s laws and the characteristics of an ideal operational amplifier for a strict piecewise linear state equation, a circuit simulation model is constructed to study the system parameters (time, C) for the current passing through an inductor with an inductance of L and the voltage across the capacitor with a capacitance of C. The developed simulation model uses Runge-Kutta methods to solve the state equations. This study focuses on predicting the fault of the circuit from the two aspects of the harmonic distortion and simulation results. Moreover, the presented model is also used to research the working state of the system in the case of a load capacitance catastrophe. The nonlinear dynamic behaviors in the inverter are simulated and verified.

  14. Accurate and Less-Disturbing Active Anti-Islanding Method based on PLL for Grid-Connected PV Inverters

    DEFF Research Database (Denmark)

    Ciobotaru, Mihai; Agelidis, Vassilios; Teodorescu, Remus

    2008-01-01

    Islanding prediction is a necessary feature of inverter-based photovoltaic (PV) system in order to meet stringent standard requirements for interconnection with the electrical grid. Both passive and active anti-islanding methods exist. Typically, active methods modify a given parameter, which also...... extracted from the voltage at PCC moves outside of a preset threshold value. This new active anti-islanding method meets both standard requirements IEEE 929-2000, IEEE 1547.1 and VDE 0126.1.1. The disturbance used by this method is small compared to other active anti-islanding methods, such as active...

  15. Leakage current measurement in transformerless PV inverters

    DEFF Research Database (Denmark)

    Kerekes, Tamas; Sera, Dezso; Mathe, Laszlo

    2012-01-01

    Photovoltaic (PV) installations have seen a huge increase during the last couple of years. Transformerless PV inverters are gaining more share of the total inverter market, due to their high conversion efficiency, small weight and size. Nevertheless safety should have an important role in case...... of these tranformerless systems, due to the missing galvanic isolation. Leakage and fault current measurement is a key issue for these inverter topologies to be able to comply with the required safety standards. This article presents the test results of two different current measurement sensors that were suggested...

  16. Online Variable Topology-Type Photovoltaic Grid-Connected Inverter

    DEFF Research Database (Denmark)

    Wu, Fengjiang; Sun, Bo; Duan, Jiandong

    2015-01-01

    In photovoltaic (PV) grid-connected generation system, the key focus is how to expand the generation range of the PV array and enhance the total efficiency of the system. This paper originally derived expressions of the total loss and grid current total harmonics distortions of cascaded inverter...... and H-bridge inverter under the conditions of variable output voltage and power of the PV array. It is proved that, compared with the H-bridge inverter, the operation range of the cascaded inverter is wider, whereas the total loss is larger. Furthermore, a novel online variable topology-type grid......-connected inverter is proposed. A bidirectional power switch is introduced into the conventional cascaded inverter to connect the negative terminals of the PV arrays. When the output voltages of the PV arrays are lower, the proposed inverter works under cascaded inverter mode to obtain wider generation range. When...

  17. Reliability Assessment of Transformerless PV Inverters considering Mission Profiles

    Directory of Open Access Journals (Sweden)

    Yongheng Yang

    2015-01-01

    Full Text Available Due to the small volume and high efficiency, transformerless inverters have gained much popularity in grid-connected PV applications, where minimizing leakage current injection is mandatory. This can be achieved by either modifying the modulation schemes or adding extra power switching devices, resulting in an uneven distribution of the power losses on the switching devices. Consequently, the device thermal loading is redistributed and thus may alter the entire inverter reliability performance, especially under a long-term operation. In this consideration, this paper assesses the device reliability of three transformerless inverters under a yearly mission profile (i.e., solar irradiance and ambient temperature. The mission profile is translated to device thermal loading, which is used for lifetime prediction. Comparison results reveal the lifetime mismatches among the power switching devices operating under the same condition, which offers new thoughts for a robust design and a reliable operation of grid-connected transformerless PV inverters with high efficiency.

  18. Impacts of PV Array Sizing on PV Inverter Lifetime and Reliability

    DEFF Research Database (Denmark)

    Sangwongwanich, Ariya; Yang, Yongheng; Sera, Dezso

    2017-01-01

    . However, oversizing the PV array will increase the loading of PV inverters, which may have undesired influence on the PV inverter lifetime and reliability. In that case, it may result in a negative impact on the overall PV energy cost, due to the increased maintenance for the PV inverters. This paper...... evaluates the lifetime of PV inverters considering the PV array sizing and installation sites, e.g., Denmark and Arizona. The results reveal that the PV array sizing has a considerable impact on the PV inverter lifetime and reliability, especially in Denmark, where the average solar irradiance level...

  19. Experimental grid connected PV system power analysis

    Science.gov (United States)

    Semaoui, Smail; Abdeladim, Kamel; Arab, Amar Hadj; Boulahchich, Saliha; Amrouche, Said Ould; Yassaa, Noureddine

    2018-05-01

    Almost 80 % of Algerian territory is appropriate for the exploitation of solar energy. The Algerian energetic strategy provides a substantial injection of PV electricity to the national grid. Currently, about 344 MWp of PV arrays which corresponds approximately to 2,34 km2 of module surfaces, are connected on electricity grid over the national territory. The Algerian Northern regions are characterized by strong pollution and high humidity. These phenomena affect the energetic productivity of PV generator. The objective of our study is to analyze experimental grid connected PV system power in coastal locations. Hence, experiments have been conducted on three identical PV systems to determine the electrical performances. Transformer-less inverters are the most attractive for the ground-based photovoltaic (PV) system due to their efficiencies, reduced cost and weight. Besides, the absence of the galvanic isolation generates problems of capacitive leakage current on the AC side and the degradation of the insulation resistance on the DC side of the inverter. In this work, experimental study of the behavior of single-phase inverters without transformers is presented. The main objective of this work is to study the degradation of the insulation resistance at the input of the inverter, and the capacitive leakage current at the output of the inverter. This study was achieved at the CDER on a rainy day of 15/03/2017, on the first PV plant connected to the low voltage network in Algeria. This investigation can help forecasting the PV array energetic production by taking into account natural conditions.

  20. PV inverter test setup for European efficiency, static and dynamic MPPT efficiency evaluation

    DEFF Research Database (Denmark)

    Sera, Dezso; Teodorescu, Remus; Valentini, Massimo

    2008-01-01

    This paper concerns the evaluation of performance of grid-connected PV inverters in terms of conversion efficiency, European efficiency, static and dynamic MPP efficiency. Semi-automated tests were performed in the PV laboratory of the Institute of Energy Technology at the Aalborg University...... (Denmark) on a commercial transformerless PV inverter. Thanks to the available experimental test setups, that provide the required high measuring accuracy, and the developed PV simulator, which is required for MPPT performance evaluation, PV Inverters can be pretested before being tested by accredited...

  1. Interharmonics from Grid-Connected PV Systems

    DEFF Research Database (Denmark)

    Sangwongwanich, Ariya; Yang, Yongheng; Sera, Dezso

    2017-01-01

    As the penetration level of grid-connected Photovoltaic (PV) systems increases, the power quality is one of the major concerns for system operators and the demands are becoming even stricter. The impact of interharmonics on the grid has been acknowledged in recent research when considering a large......-scale adoption of PV inverters. However, the origins of interharmonics remain unclear. Thus, this paper performs tests on a commercial PV inverter to explore interharmonic generation and more important investigates the mechanism of interharmonic emission. The investigation reveals that the perturbation...... of the solutions. Simulation results indicate that the constant-voltage MPPT method is the most suitable solution to the mitigation of interharmonics introduced by the MPPT operation, as it avoids the perturbation in the PV voltage during operation....

  2. Optimal design of NPC and Active-NPC transformerless PV inverters

    DEFF Research Database (Denmark)

    Saridakis, Stefanos; Koutroulis, Eftichios; Blaabjerg, Frede

    2012-01-01

    Targeting at a cost-effective deployment of grid-connected PhotoVoltaic (PV) systems, this paper presents a new methodology for the optimal design of transformerless PV inverters, which are based on the Neutral Point Clamped (NPC) and the Active-Neutral Point Clamped (ANPC) topologies. The design...... optimization results demonstrate that a different set of optimal values of the PV inverter switching frequency and output filter components are derived for the NPC and ANPC topologies, respectively, as well as for each of the PV inverter installation sites under study. The NPC and ANPC PV inverter structures......, which are derived using the proposed design optimization methodology exhibit lower Levelized Cost Of generated Electricity (LCOE) and manufacturing cost and they are simultaneously capable to inject more energy into the electric grid than the corresponding non-optimized PV inverters. Thus, the proposed...

  3. A single phase photovoltaic inverter control for grid connected system

    Indian Academy of Sciences (India)

    This paper presents a control scheme for single phase grid connected photovoltaic (PV) system operating under both grid connected and isolated grid mode. The control techniques include voltage and current control of grid-tie PV inverter. During grid connected mode, grid controls the amplitude and frequency of the PV ...

  4. Optimal Design of Modern Transformerless PV Inverter Topologies

    DEFF Research Database (Denmark)

    Saridakis, Stefanos; Koutroulis, Eftichios; Blaabjerg, Frede

    2013-01-01

    the operational lifetime period of the PV installation, is also considered in the optimization process. According to the results of the proposed design method, different optimal values of the PV inverter design variables are derived for each PV inverter topology and installation site. The H5, H6, neutral point...... clamped, active-neutral point clamped and conergy-NPC PV inverters designed using the proposed optimization process feature lower levelized cost of generated electricity and lifetime cost, longer mean time between failures and inject more PV-generated energy into the electric grid than their nonoptimized......The design optimization of H5, H6, neutral point clamped, active-neutral point clamped, and conergy-NPC transformerless photovoltaic (PV) inverters is presented in this paper. The components reliability in terms of the corresponding malfunctions, affecting the PV inverter maintenance cost during...

  5. Optimal Design of Modern Transformerless PV Inverter Topologies

    OpenAIRE

    Saridakis, Stefanos; Koutroulis, Eftichios; Blaabjerg, Frede

    2013-01-01

    The design optimization of H5, H6, neutral point clamped, active-neutral point clamped, and conergy-NPC transformerless photovoltaic (PV) inverters is presented in this paper. The components reliability in terms of the corresponding malfunctions, affecting the PV inverter maintenance cost during the operational lifetime period of the PV installation, is also considered in the optimization process. According to the results of the proposed design method, different optimal values of the PV inver...

  6. Impacts of PV Array Sizing on PV Inverter Lifetime and Reliability

    OpenAIRE

    Sangwongwanich, Ariya; Yang, Yongheng; Sera, Dezso; Blaabjerg, Frede

    2017-01-01

    In order to enable a more wide-scale utilization of PV systems, the cost of PV energy has to be comparable with other energy sources. Oversizing the PV array is one common approach to reduce the cost of PV energy, since it increases the PV energy yield during low solar irradiance conditions. However, oversizing the PV array will increase the loading of PV inverters, which may have undesired influence on the PV inverter lifetime and reliability. In that case, it may result in a negative impact...

  7. Reliability Assessment of Transformerless PV Inverters Considering Mission Profiles

    DEFF Research Database (Denmark)

    Yang, Yongheng; Wang, Huai; Blaabjerg, Frede

    2015-01-01

    reliability of three transformerless inverters under a yearly mission profile (i.e., solar irradiance and ambient temperature). The mission profile is translated to device thermal loading, which is used for lifetime prediction. Compar¬ison results reveal the lifetime mismatches among the power switching......Due to the small volume and high efficiency, transformerless inverters have gained much popularity in grid-connected PV applications, where minimizing leakage current injection is mandatory. This can be achieved either by modifying the modulation schemes or adding extra power switching devices......, resulting in an uneven distribution of the power losses on the switching devices. Consequently, the device thermal loading is redis-tributed, and thus may alter the entire inverter reliability performance, especially under a long-term operation. In this consideration, this paper assesses the device...

  8. Control of Grid Interactive PV Inverters for High Penetration in Low Voltage Distribution Networks

    DEFF Research Database (Denmark)

    Demirok, Erhan

    Regarding of high density deployment of PV installations in electricity grids, new technical challenges such as voltage rise, thermal loading of network components, voltage unbalance, harmonic interaction and fault current contributions are being added to tasks list of distribution system operators...... of these inverters may depend on grid connection rules which are forced by DSOs. Minimum requirement expected from PV inverters is to transfer maximum power by taking direct current (DC) form from PV modules and release it into AC grid and also continuously keep the inverters synchronized to the grid even under...... for this problem but PV inverters connected to highly capacitive networks are able to employ extra current and voltage harmonics compensation to avoid triggering network resonances at low order frequencies. The barriers such as harmonics interaction, flicker, fault current contribution and dc current injections...

  9. A Hybrid Power Control Concept for PV Inverters with Reduced Thermal Loading

    DEFF Research Database (Denmark)

    Yang, Yongheng; Wang, Huai; Blaabjerg, Frede

    2014-01-01

    on a single-phase PV inverter under yearly operation is presented with analyses of the thermal loading, lifetime, and annual energy yield. It has revealed the trade-off factors to select the power limit and also verified the feasibility and the effectiveness of the proposed control concept.......This letter proposes a hybrid power control concept for grid-connected Photovoltaic (PV) inverters. The control strategy is based on either a Maximum Power Point Tracking (MPPT) control or a Constant Power Generation (CPG) control depending on the instantaneous available power from the PV panels....... The essence of the proposed concept lies in the selection of an appropriate power limit for the CPG control to achieve an improved thermal performance and an increased utilization factor of PV inverters,and thus to cater for a higher penetration level of PV systems with intermittent nature. A case study...

  10. Thermal Optimized Operation of the Single-Phase Full-Bridge PV Inverter under Low Voltage Ride-Through Mode

    DEFF Research Database (Denmark)

    Wang, Huai; Yang, Yongheng; Blaabjerg, Frede

    2013-01-01

    The efficiency of 98% has been reported on transformer-less photovoltaic (PV) inverters and the penetration of grid-connected PV systems is booming as well. In the future, the PV systems are expected to contribute to the grid stability by means of low voltage ride-through operation and grid suppo...

  11. Real field mission profile oriented design of a SiC-based PV-inverter application

    DEFF Research Database (Denmark)

    Sintamarean, Nicolae Christian; Blaabjerg, Frede; Wang, Huai

    2013-01-01

    This paper introduces a real field mission profile oriented design tool for the new generation of grid connected PV-inverters applications based on SiC-devices. The proposed design tool consists of a grid connected PV-inverter model, an ElectroThermal model, a converter safe operating area (SOA...... Zth_H in order to perform in a safe mode for the whole operating range. Furthermore, the proposed design tool considers the mission profile (the measured solar irradiance and ambient temperature) from the real field where the converter will operate. Thus, a realistic loading of the converter devices......) model, a mission profile model and an the evaluation block. The PV-system model involves a three level bipolar switch neutral point clamped (3L-BS NPC) inverter connected to the three phase grid through a LCL-filter. Moreover, the SOA model calculates the required converter heatsink thermal impedance...

  12. A New Control Structure for Grid-Connected LCL PV Inverters with Zero Steady-State Error and Selective Harmonic Compensation

    DEFF Research Database (Denmark)

    Teodorescu, Remus; Blaabjerg, Frede; Borup, Uffe

    2004-01-01

    disturbance rejection capability leads to the need of grid feed-forward compensation. However the imperfect compensation action of the feed-forward control results in high harmonic distortion of the current and consequently non-compliance with international standards. In this paper a new control strategy...... aimed to mitigate these problems is proposed. Stationary-frame generalized integrators are used to control the fundamental current and to compensate the grid harmonics providing disturbance rejection capability without the need of feed-forward grid compensation. Moreover the use of a grid LCL......The PI current control of a single-phase inverter has well known drawbacks: steady-state magnitude and phase-error and limited disturbance rejection capability. When the current controlled inverter is connected to the grid, the phase error results in a power factor decrement and the limited...

  13. Control of Single-Stage Single-Phase PV inverter

    DEFF Research Database (Denmark)

    Ciobotaru, Mihai; Teodorescu, Remus; Blaabjerg, Frede

    2005-01-01

    In this paper the issue of control strategies for single-stage photovoltaic (PV) inverter is addressed. Two different current controllers have been implemented and an experimental comparison between them has been made. A complete control structure for the single-phase PV system is also presented......-forward; - and the grid current controller implemented in two different ways, using the classical proportional integral (PI) and the novel proportional resonant (PR) controllers. The control strategy was tested experimentally on 1.5 kW PV inverter....

  14. Current Harmonics from Single-Phase Grid-Connected Inverters

    DEFF Research Database (Denmark)

    Yang, Yongheng; Zhou, Keliang; Blaabjerg, Frede

    2016-01-01

    Environmental conditions and operational modes may significantly impact the distortion level of the injected current from single-phase grid-connected inverter systems, such as photovoltaic (PV) inverters, which may operate in cloudy days with a maximum power point tracking, in a non-unity power...... factor, or in the low voltage ride through mode with reactive current injection. In this paper, the mechanism of the harmonic current injection from grid-connected single-phase inverter systems is thus explored, and the analysis is conducted on single-phase PV systems. In particular, the analysis...... is focused on the impacts of the power factor and the feed-in grid current level on the quality of the feed-in grid current from single-phase inverters. As a consequence, an internal model principle based high performance current control solution is tailor-made and developed for single-phase grid-connected...

  15. Review of PV Inverter Technology Cost and Performance Projections

    Energy Technology Data Exchange (ETDEWEB)

    Navigant Consulting Inc.

    2006-01-01

    The National Renewable Energy Laboratory (NREL) has a major responsibility in the implementation of the U.S. Department of Energy's (DOE's) Solar Energy Technologies Program. Sandia National Laboratories (SNL) has a major role in supporting inverter development, characterization, standards, certifications, and verifications. The Solar Energy Technologies Program recently published a Multiyear Technical Plan, which establishes a goal of reducing the Levelized Energy Cost (LEC) for photovoltaic (PV) systems to $0.06/kWh by 2020. The Multiyear Technical Plan estimates that, in order to meet the PV system goal, PV inverter prices will need to decline to $0.25-0.30 Wp by 2020. DOE determined the need to conduct a rigorous review of the PV Program's technical and economic targets, including the target set for PV inverters. NREL requested that Navigant Consulting Inc.(NCI) conduct a review of historical and projected cost and performance improvements for PV inverters, including identification of critical barriers identified and the approaches government might use to address them.

  16. Optimization of PV-based energy production by dynamic PV-panel/inverter configuration

    DEFF Research Database (Denmark)

    Paasch, Kasper; Nymand, Morten; Haase, Frerk

    This paper investigates the possible increase in annual energy production of a PV system with more than one MPPT (maximum power point tracker) input channels under Nordic illumination conditions, in case a concept of dynamic switching of the PV panels is used at the inputs of the inverters....

  17. Optimization of SiC-based H5 and conergy-NPC transformerless PV inverters

    DEFF Research Database (Denmark)

    Saridakis, Stefanos; Koutroulis, Eftichios; Blaabjerg, Frede

    2015-01-01

    The transformerless dc/ac inverters are critical components in the rapidly growing market of grid-connected photovoltaic (PV) applications. They are synthesized by combining available solutions in terms of the power-section topology, power-semiconductors manufacturing technology, and structure...

  18. Frequency Adaptive Repetitive Control of Grid-Tied Single-Phase PV Inverters

    DEFF Research Database (Denmark)

    Zhou, Keliang; Yang, Yongheng; Blaabjerg, Frede

    2015-01-01

    . This paper thus explores a frequency adaptive repetitive control strategy for grid converters, which employs fractional delay filters in order to adapt to the change of the grid frequency. Case studies with experimental results of a single-phase grid-connected PV inverter system are provided to verify...

  19. Design of Solar PV Cell Based Inverter for Unbalanced and Distorted Industrial Loads

    Directory of Open Access Journals (Sweden)

    Naga Ananth D

    2015-04-01

    Full Text Available PV cell is getting importance in low and medium power generation due to easy installation, low maintenance and subsidies in price from respective nation. Most of the loads in distribution system are unbalanced and distorted, due to which there will be unbalanced voltage and current occur at load and may disturb its overall performance. Due to these loads voltage unbalance, distorted voltage and current and variable power factors in each phase can be observed. An efficient algorithm to mitigate unbalanced and distorted load and source voltage and current in solar photo voltaic (PV inverter for isolated load system was considered. This solar PV system can be applicable to remote located industrial loads like heating, welding and small arc furnace type distorted loads and also for unbalanced loads. The PV inverter is designed such that it will maintain nearly constant voltage magnitude and can mitigate harmonics in voltage and current near the load terminals. A MATLAB/ SIMULINK based solar PV inverter was simulated and results are compared with standard AC three phase grid connected system. The proposed shows that the inverter is having very less voltage and current harmonic content and can maintain nearly constant voltage profile for highly unbalanced system.

  20. Experimental Evaluation of PV Inverter Anti-Islanding with Grid Support Functions in Multi-Inverter Island Scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Hoke, Anderson [National Renewable Energy Lab. (NREL), Golden, CO (United States); Nelson, Austin [National Renewable Energy Lab. (NREL), Golden, CO (United States); Miller, Brian [National Renewable Energy Lab. (NREL), Golden, CO (United States); Chakraborty, Sudipta [National Renewable Energy Lab. (NREL), Golden, CO (United States); Bell, Frances [SolarCity, San Mateo, CA (United States); McCarty, Michael [SolarCity, San Mateo, CA (United States)

    2016-07-01

    As PV and other DER systems are connected to the grid at increased penetration levels, island detection may become more challenging for two reasons: 1.) In islands containing many DERs, active inverter-based anti-islanding methods may have more difficulty detecting islands because each individual inverter's efforts to detect the island may be interfered with by the other inverters in the island. 2.) The increasing numbers of DERs are leading to new requirements that DERs ride through grid disturbances and even actively try to regulate grid voltage and frequency back towards nominal operating conditions. These new grid support requirements may directly or indirectly interfere with anti-islanding controls. This report describes a series of tests designed to examine the impacts of both grid support functions and multi-inverter islands on anti-islanding effectiveness. Crucially, the multi-inverter anti-islanding tests described in this report examine scenarios with multiple inverters connected to multiple different points on the grid. While this so-called 'solar subdivision' scenario has been examined to some extent through simulation, this is the first known work to test it using hardware inverters. This was accomplished through the use of power hardware-in-the-loop (PHIL) simulation, which allows the hardware inverters to be connected to a real-time transient simulation of an electric power system that can be easily reconfigured to test various distribution circuit scenarios. The anti-islanding test design was a modified version of the unintentional islanding test in IEEE Standard 1547.1, which creates a balanced, resonant island with the intent of creating a highly challenging condition for island detection. Three common, commercially available single-phase PV inverters from three different manufacturers were tested. The first part of this work examined each inverter individually using a series of pure hardware resistive-inductive-capacitive (RLC

  1. A Single-Phase Transformerless Inverter With Charge Pump Circuit Concept for Grid-Tied PV Applications

    DEFF Research Database (Denmark)

    Ardashir, Jaber Fallah; Sabahi, Mehran; Hosseini, Seyed Hossein

    2017-01-01

    This paper proposes a new single-phase transformerless photovoltaic (PV) inverter for grid-tied PV systems. The topology is derived from the concept of a charge pump circuit in order to eliminate the leakage current. It is composed of four power switches, two diodes, two capacitors, and an LCL...... resonant control strategy is used to control the injected current. The main benefits of the proposed inverter are: the neutral of the grid is directly connected to the negative terminal of the PV panel, so the leakage current is eliminated; its compact size; low cost; the used dc voltage of the proposed...... are presented. Experimental results are presented to confirm both the theoretical analysis and the concept of the proposed inverter. The obtained results clearly validate the performance of the proposed inverter and its practical application in grid-tied PV systems....

  2. Reliability Analysis of Single-Phase PV Inverters with Reactive Power Injection at Night Considering Mission Profiles

    DEFF Research Database (Denmark)

    Anurag, Anup; Yang, Yongheng; Blaabjerg, Frede

    2015-01-01

    loading, considering the operation outside active feed-in hours. An analytical lifetime model is then employed for lifetime quantization based on the Palgrem Miner rule. Thereafter, considering the lifetime reduction of the PV inverter under different mission profiles with reactive power injection......The widespread adoption of mixed renewables urgently require reactive power exchange at various feed-in points of the utility grid. Photovoltaic (PV) inverters are able to provide reactive power in a decentralized manner at the grid-connection points even outside active power feed-in operation......, especially at night when there is no solar irradiance. This serves as a motivation for utilizing the PV inverters at night for reactive power compensation. Thus, an analysis on the impact of reactive power injection by PV inverters outside feed-in operation on the thermal performance and the reliability has...

  3. Control of a Multi-Functional Inverter for Grid Integration of PV and Battery Energy Storage System

    DEFF Research Database (Denmark)

    Mousazadeh, Seyyed Yousef; Firoozabadi, Mehdi Savaghebi; Beirami, A.

    2015-01-01

    This paper presents a multi-functional control of a DC/AC inverter for Power Quality compensation of nonlinear and unequal local loads and grid integration of hybrid photovoltaic (PV) and battery energy storage systems. Multi-layer neural network estimator and a DC/DC converter are used for maximum...... is used for delivering desire power to the grid. For compensation aim, instantaneous active and reactive power theory (p-q) is used. Via the algorithm, the DC/AC inverter not only can be controlled to inject the power of battery and PV, but also it is used as shunt active filter for compensating unequal...... power point tracking (MPPT) of PV array. The power system is 3-phase 4-wires and the DC/AC inverter is chosen 4-leg three phase inverter which has good performance in presence of zero sequence components. Battery energy storage is connected to PV system in common DC bus and a power management strategy...

  4. An Improved Fuzzy Logic Controller Design for PV Inverters Utilizing Differential Search Optimization

    Directory of Open Access Journals (Sweden)

    Ammar Hussein Mutlag

    2014-01-01

    Full Text Available This paper presents an adaptive fuzzy logic controller (FLC design technique for photovoltaic (PV inverters using differential search algorithm (DSA. This technique avoids the exhaustive traditional trial and error procedure in obtaining membership functions (MFs used in conventional FLCs. This technique is implemented during the inverter design phase by generating adaptive MFs based on the evaluation results of the objective function formulated by the DSA. In this work, the mean square error (MSE of the inverter output voltage is used as an objective function. The DSA optimizes the MFs such that the inverter provides the lowest MSE for output voltage and improves the performance of the PV inverter output in terms of amplitude and frequency. The design procedure and accuracy of the optimum FLC are illustrated and investigated using simulations conducted for a 3 kW three-phase inverter in a MATLAB/Simulink environment. Results show that the proposed controller can successfully obtain the desired output when different linear and nonlinear loads are connected to the system. Furthermore, the inverter has reasonably low steady state error and fast response to reference variation.

  5. The Impact of Gate-Driver Parameters Variation and Device Degradation in the PV-Inverter Lifetime

    DEFF Research Database (Denmark)

    Sintamarean, Nicolae Cristian; Wang, Huai; Blaabjerg, Frede

    2014-01-01

    of the lifetime estimation it is crucial to consider also the device degradation feedback. Moreover the MP of the field where the PV-inverter is operating and the GD parameters selection has an important impact in the converter reliability and it should be considered from the design stage to better optimize......This paper introduces a reliability-oriented design tool for a new generation of grid connected PV-inverters. The proposed design tool consists of a real field Mission Profile (MP) model (for one year operation in USA-Arizona), a PV-panel model, a grid connected PV-inverter model, an Electro......-Thermal model and the lifetime model of the power semiconductor devices. A simulation model able to consider a one year real field operation conditions (solar irradiance and ambient temperature) is developed. Thus, one year estimation of the converter devices thermal loading distribution is achieved...

  6. On the Impacts of PV Array Sizing on the Inverter Reliability and Lifetime

    DEFF Research Database (Denmark)

    Sangwongwanich, Ariya; Yang, Yongheng; Sera, Dezso

    2018-01-01

    , the total energy yield can be increased under weak solar irradiance conditions. However, oversizing the PV array will increase the loading of PV inverters, which may have undesired influence on the PV inverter reliability and lifetime. In that case, it may result in a negative impact on the overall PV...... energy cost, due to the increased maintenance for the PV inverters. With the above concern, this paper evaluates the reliability and lifetime of PV inverters considering the PV array sizing. The evaluation is based on the mission profile of the installation sites in Denmark and Arizona, where...... the reliability-critical components such as power devices and capacitors are considered. The results reveal that the variation in the PV array sizing can considerably deviate the reliability performance and lifetime expectation of PV inverters, especially for those installed in Denmark, where the average solar...

  7. Lifetime Evaluation of PV Inverters considering Panel Degradation Rates and Installation Sites

    DEFF Research Database (Denmark)

    Sangwongwanich, Ariya; Yang, Yongheng; Sera, Dezso

    2017-01-01

    The PV inverter lifetime is affected by the installed sites related to different solar irradiance and ambient temperature profiles. In fact, the installation site also affects the PV panel degradation rate, and thus the long-term power production. Prior-art lifetime analysis in PV inverters has...... not yet investigated the impact of panel degradation. This paper thus evaluates the lifetime of PV inverters considering panel degradation rates and installation sites. Evaluations have been carried out on PV systems installed in Denmark and Arizona. The results reveal that the PV panel degradation rate...... has a considerable impact on the PV inverter lifetime, especially in the hot climate (e.g., Arizona), where the panel degrades at a faster rate. In that case, the PV inverter lifetime estimation can be deviated by 54%, if the impact of PV panel degradation is not taken into account....

  8. Power Hardware-in-the-Loop Evaluation of PV Inverter Grid Support on Hawaiian Electric Feeders

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, Austin A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Prabakar, Kumaraguru [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Nagarajan, Adarsh [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Nepal, Shaili [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Hoke, Anderson F [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Asano, Marc [Hawaiian Electric Company; Ueda, Reid [Hawaiian Electric Company; Ifuku, Earle [Hawaiian Electric Company

    2017-10-03

    As more grid-connected photovoltaic (PV) inverters become compliant with evolving interconnections requirements, there is increased interest from utilities in understanding how to best deploy advanced grid-support functions (GSF) in the field. One efficient and cost-effective method to examine such deployment options is to leverage power hardware-in-the-loop (PHIL) testing methods, which combine the fidelity of hardware tests with the flexibility of computer simulation. This paper summarizes a study wherein two Hawaiian Electric feeder models were converted to real-time models using an OPAL-RT real-time digital testing platform, and integrated with models of GSF capable PV inverters based on characterization test data. The integrated model was subsequently used in PHIL testing to evaluate the effects of different fixed power factor and volt-watt control settings on voltage regulation of the selected feeders using physical inverters. Selected results are presented in this paper, and complete results of this study were provided as inputs for field deployment and technical interconnection requirements for grid-connected PV inverters on the Hawaiian Islands.

  9. Analysis and Design of Solar Photo voltaic Grid Connected Inverter

    Directory of Open Access Journals (Sweden)

    Muddasani Satyanarayana

    2015-08-01

    Full Text Available This paper presents common mode voltage analysis of single phase grid connected photovoltaic inverter. Many researchers proposed different grid tie inverters for applications like domestic powering, street lighting, water pumping, cooling and heating applications, however traditional grid tie PV inverter uses either a line frequency or a high frequency transformer between the inverter and grid but losses will increase in the network leading to reduced efficiency of the system. In order to increase the efficiency, with reduced size and cost of the system, the effective solution is to remove the isolation transformer. But common mode (CM ground leakage current due to parasitic capacitance between the PV panels and the ground making the system unreliable. The common mode current reduces the efficiency of power conversion stage, affects the quality of grid current, deteriorate the electric magnetic compatibility and give rise to the safety threats. In order to eliminate the common mode leakage current in Transformerless PV systm two control algorithms of multi-carrier pwm are implemented and compared for performance analysis.The shoot-through issue that is encountered by traditional voltage source inverter is analyzed for enhanced system reliability. These control algorithms are compared for common mode voltage and THD comparisons. The proposed system is designed using MATLAB/SIMULINK software for analysis.

  10. Optimization of SiC-based H5 and Conergy-NPC transformerless PV inverters

    DEFF Research Database (Denmark)

    Saridakis, Stefanos; Koutroulis, Eftichios; Blaabjerg, Frede

    2013-01-01

    effective in terms of energy production than their non-optimized and Si-based counterparts. Reducing the market price of SiC-type power semiconductors enables to design optimized PV inverters with a lower cost of energy than that of PV inverters employing Si technology, thus maximizing the economic...... profitability of the PV system....

  11. Power Hardware-in-the-Loop Evaluation of PV Inverter Grid Support on Hawaiian Electric Feeders: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, Austin; Prabakar, Kumaraguru; Nagarajan, Adarsh; Nepal, Shaili; Hoke, Anderson; Asano, Marc; Ueda, Reid; Ifuku, Earle

    2017-05-08

    As more grid-connected photovoltaic (PV) inverters become compliant with evolving interconnections requirements, there is increased interest from utilities in understanding how to best deploy advanced grid-support functions (GSF) in the field. One efficient and cost-effective method to examine such deployment options is to leverage power hardware-in-the-loop (PHIL) testing methods. Two Hawaiian Electric feeder models were converted to real-time models in the OPAL-RT real-time digital testing platform, and integrated with models of GSF capable PV inverters that were modeled from characterization test data. The integrated model was subsequently used in PHIL testing to evaluate the effects of different fixed power factor and volt-watt control settings on voltage regulation of the selected feeders. The results of this study were provided as inputs for field deployment and technical interconnection requirements for grid-connected PV inverters on the Hawaiian Islands.

  12. A grid-connected single-phase photovoltaic micro inverter

    Science.gov (United States)

    Wen, X. Y.; Lin, P. J.; Chen, Z. C.; Wu, L. J.; Cheng, S. Y.

    2017-11-01

    In this paper, the topology of a single-phase grid-connected photovoltaic (PV) micro-inverter is proposed. The PV micro-inverter consists of DC-DC stage with high voltage gain boost and DC-AC conversion stage. In the first stage, we apply the active clamp circuit and two voltage multipliers to achieve soft switching technology and high voltage gain. In addition, the flower pollination algorithm (FPA) is employed for the maximum power point tracking (MPPT) in the PV module in this stage. The second stage cascades a H-bridge inverter and LCL filter. To feed high quality sinusoidal power into the grid, the software phase lock, outer voltage loop and inner current loop control method are adopted as the control strategy. The performance of the proposed topology is tested by Matlab/Simulink. A PV module with maximum power 300W and maximum power point voltage 40V is applied as the input source. The simulation results indicate that the proposed topology and the control strategy are feasible.

  13. A design tool to study the impact of mission-profile on the reliability of SiC-based PV-inverter devices

    DEFF Research Database (Denmark)

    Sintamarean, Nicolae Cristian; Wang, Huai; Blaabjerg, Frede

    2014-01-01

    and is further used as an input to a lifetime model. The proposed reliability oriented design tool is used to study the impact of MP and device degradation (aging) in the PV-inverter lifetime. The obtained results indicate that the MP of the field where the PV-inverter is operating has an important impact......This paper introduces a reliability-oriented design tool for a new generation of grid connected PV-inverters. The proposed design tool consists of a real field mission profile model (for one year operation in USA-Arizona), a PV-panel model, a grid connected PV-inverter model, an electro......-thermal model and the lifetime model of the power semiconductor devices. A simulation model able to consider one year real field operation conditions (solar irradiance and ambient temperature) is developed. Thus, one year estimation of the converter devices thermal loading distribution is achieved...

  14. Fault Ride-Through of a Grid-connected Photovoltaic System with Quasi Z Source Inverter

    DEFF Research Database (Denmark)

    Al-Durra, Ahmed; Fayyad, Yara; Muyeen, S.M.

    2016-01-01

    This article presents fault ride-through schemes for a three-phase quasi Z source single-stage photovoltaic (PV) inverter that is connected to the grid after the distribution network. The quasi Z source inverter employs a unique LC network to couple the inverter main circuit to the input of the PV...... the grid side so that the grid fault ride-through requirements can be fulfilled. Scheme A involves control modification in the system; Schemes B and C involve hardware modification in the circuit topology by adding a chopper circuit across the DC link in Scheme B and across the quasi Z source inverter...

  15. A Novel Flying Capacitor Transformerless Inverter for Single-Phase Grid Connected Solar Photovoltaic System

    DEFF Research Database (Denmark)

    Siwakoti, Yam Prasad; Blaabjerg, Frede

    2016-01-01

    This paper proposes a new single-phase flying capacitor transformerless PV inverter for grid-connected photovoltaic (PV) systems. The neutral of the grid can be directly connected to the negative terminal of the source (PV). It consists of four power switches, one diode, one capacitor and a small...... and some topologies, which requires two times of the peak ac-voltage magnitude) and, (5) the flying capacitor charges every switching cycle, which reduces the size of the required capacitor with switching frequency. In addition, industry standard half bridge module can be used in the new inverter without...

  16. A review of single-phase grid-connected inverters for photovoltaic modules

    DEFF Research Database (Denmark)

    Kjaer, Soren Baekhoej; Pedersen, John Kim; Blaabjerg, Frede

    2005-01-01

    -phase grid; 3) whether they utilizes a transformer (either line or high frequency) or not; and 4) the type of grid-connected power stage. Various inverter topologies are presented, compared, and evaluated against demands, lifetime, component ratings, and cost. Finally, some of the topologies are pointed out......This review focuses on inverter technologies for connecting photovoltaic (PV) modules to a single-phase grid. The inverters are categorized into four classifications: 1) the number of power processing stages in cascade; 2) the type of power decoupling between the PV module(s) and the single...

  17. On the Impacts of PV Array Sizing on the Inverter Reliability and Lifetime

    OpenAIRE

    Sangwongwanich, Ariya; Yang, Yongheng; Sera, Dezso; Blaabjerg, Frede; Zhou, Dao

    2018-01-01

    To enable a more wide scale utilization of PV systems, the cost of PV energy should be comparable to or even lower than other energy sources. Due to the relatively low cost of PV modules, oversizing PV arrays becomes a common approach to reduce the cost of PV energy in practice. By doing so, the total energy yield can be increased under weak solar irradiance conditions. However, oversizing the PV array will increase the loading of PV inverters, which may have undesired influence on the PV inv...

  18. Three-level grid-connected photovoltaic inverter with maximum power point tracking

    International Nuclear Information System (INIS)

    Tsang, K.M.; Chan, W.L.

    2013-01-01

    Highlight: ► This paper reports a novel 3-level grid connected photovoltaic inverter. ► The inverter features maximum power point tracking and grid current shaping. ► The inverter can be acted as an active filter and a renewable power source. - Abstract: This paper presents a systematic way of designing control scheme for a grid-connected photovoltaic (PV) inverter featuring maximum power point tracking (MPPT) and grid current shaping. Unlike conventional design, only four power switches are required to achieve three output levels and it is not necessary to use any phase-locked-loop circuitry. For the proposed scheme, a simple integral controller has been designed for the tracking of the maximum power point of a PV array based on an improved extremum seeking control method. For the grid-connected inverter, a current loop controller and a voltage loop controller have been designed. The current loop controller is designed to shape the inverter output current while the voltage loop controller can maintain the capacitor voltage at a certain level and provide a reference inverter output current for the PV inverter without affecting the maximum power point of the PV array. Experimental results are included to demonstrate the effectiveness of the tracking and control scheme.

  19. The Impact of Transformer Winding Connections of A Grid-Connected PV on Voltage Quality Improvement

    Energy Technology Data Exchange (ETDEWEB)

    Muljadi, Eduard [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Tumbelaka, Hanny H. [Petra Christian University; Gao, Wenzhong [University of Denver

    2018-03-01

    In this paper, the high-power PV plant is connected to the weak grid by means of a three-phase power transformer. The selection of transformer winding connection is critical especially when the PV inverter has a reactive power controller. In general, transformer winding connection can be arranged in star-star (with neutral earthed) or star-delta. The reactive power controller supports voltage regulation of the power system particularly under transient faults. Its control strategy is based on utilizing the grid currents to make a three-phase reactive unbalanced current with a small gain. The gain is determined by the system impedance. Simulation results exhibit that the control strategy works very well particularly under disturbance conditions when the transformer winding connection is star-star with both neutrals grounded. The power quality in terms of the voltage quality is improved.

  20. Rapid islanding detection using multi-level inverter for grid-interactive PV system

    International Nuclear Information System (INIS)

    Tsang, K.M.; Chan, W.L.

    2014-01-01

    Graphical abstract: - Highlights: • Novel reference signal is used to form an islanding detection scheme for PV system. • Supply fixed magnitude sinusoidal signal even if utility grid is disconnected. • Seamless transfer between grid-connected and stand-alone modes is possible. - Abstract: A novel reference signal generator is combined with a multi-level inverter to form a rapid islanding detection scheme for grid-interactive PV system. The reference signal generator can easily be synchronized with the utility grid signal and produced a fixed magnitude and very low total harmonic distortion (THD) sinusoidal signal which is in phase with the utility grid signal. Unlike conventional phase-locked loop (PLL) circuitry, the reference signal generator can also provide a fixed magnitude sinusoidal signal even if the utility grid is disconnected and automatically re-synchronous with the grid rapidly. Consequently, seamless transfer between grid-connected and stand-alone modes could easily be achieved if anti-islanding protection is not required. If a saturation element is applied to the raw reference signal followed by the synthesis of the truncated signal using a multi-level inverter, the distinct flat-top feature of the synthesized signal can quickly and easily be identified if the network is in islanding mode at the point of common coupling. Experimental results are included to demonstrate the effectiveness of the proposed detection scheme

  1. Transformerless Photovoltaic Inverters Connected to the Grid

    DEFF Research Database (Denmark)

    Kerekes, Tamas; Teodorescu, Remus; Borup, Uffe

    2007-01-01

    Renewable energy sources are getting more and more widespread, mainly due to the fact that they generate energy by keeping the environment clean. Most of these systems have an isolation transformer included, which if excluded from the system would increase the efficiency and decrease the size of PV......-phase with respect to the leakage current generation. The best results, both for single-phase and three-phase systems, are obtained when the middle point of the input capacitors is connected to the neutral point, thereby minimizing the voltage fluctuations present at the terminals of the PV panel....

  2. Methodology for the optimal design of tansformerless grid-connected PV interters

    DEFF Research Database (Denmark)

    Koutroulis, E.; Blaabjerg, Frede

    2012-01-01

    inverter, such that the PV inverter levelised cost of the generated electricity is minimised. The proposed method constitutes a systematic design process, which is capable to explore the impact of the PV inverter configuration on the trade-off between the PV inverter manufacturing cost and the power losses...

  3. Coordinated Voltage Control of Distributed PV Inverters for Voltage Regulation in Low Voltage Distribution Networks

    DEFF Research Database (Denmark)

    Nainar, Karthikeyan; Pokhrel, Basanta Raj; Pillai, Jayakrishnan Radhakrishna

    2017-01-01

    This paper reviews and analyzes the existing voltage control methods of distributed solar PV inverters to improve the voltage regulation and thereby the hosting capacity of a low-voltage distribution network. A novel coordinated voltage control method is proposed based on voltage sensitivity...... optimization. The proposed method is used to calculate the voltage bands and droop settings of PV inverters at each node by the supervisory controller. The local controller of each PV inverter implements the volt/var control and if necessary, the active power curtailment as per the received settings and based...... on measured local voltages. The advantage of the proposed method is that the calculated reactive power and active power droop settings enable fair contribution of the PV inverters at each node to the voltage regulation. Simulation studies are conducted using DigSilent Power factory software on a simplified...

  4. Final Report Report: Smart Grid Ready PV Inverters with Utility Communication

    Energy Technology Data Exchange (ETDEWEB)

    Seal, Brian [Electric Power Research Inst. (EPRI), Knovville, TN (United States); Huque, Aminul [Electric Power Research Inst. (EPRI), Knovville, TN (United States); Rogers, Lindsey [Electric Power Research Inst. (EPRI), Knovville, TN (United States); Key, Tom [Electric Power Research Inst. (EPRI), Knovville, TN (United States); Riley, Cameron [Electric Power Research Inst. (EPRI), Knovville, TN (United States); Li, Huijuan [Electric Power Research Inst. (EPRI), Knovville, TN (United States); York, Ben [Electric Power Research Inst. (EPRI), Knovville, TN (United States); Purcell, Chris [BPL Global, Inc., Canonsburg, PA (United States); Pacific, Oliver [Spirae, Inc., Fort Collins, CO (United States); Ropp, Michael [Northern Plains Power Technologies, Brookings, SD (United States); Tran, Teresa [DTE Energy, Detroit, MI (United States); Asgeirsson, Hawk [DTE Energy, Detroit, MI (United States); Woodard, Justin [National Grid, Warwick (United Kingdom); Steffel, Steve [Pepco Holdings, Inc., Washington, DC (United States)

    2016-03-30

    In 2011, EPRI began a four-year effort under the Department of Energy (DOE) SunShot Initiative Solar Energy Grid Integration Systems - Advanced Concepts (SEGIS-AC) to demonstrate smart grid ready inverters with utility communication. The objective of the project was to successfully implement and demonstrate effective utilization of inverters with grid support functionality to capture the full value of distributed photovoltaic (PV). The project leveraged ongoing investments and expanded PV inverter capabilities, to enable grid operators to better utilize these grid assets. Developing and implementing key elements of PV inverter grid support capabilities will increase the distribution system’s capacity for higher penetration levels of PV, while reducing the cost. The project team included EPRI, Yaskawa-Solectria Solar, Spirae, BPL Global, DTE Energy, National Grid, Pepco, EDD, NPPT and NREL. The project was divided into three phases: development, deployment, and demonstration. Within each phase, the key areas included: head-end communications for Distributed Energy Resources (DER) at the utility operations center; methods for coordinating DER with existing distribution equipment; back-end PV plant master controller; and inverters with smart-grid functionality. Four demonstration sites were chosen in three regions of the United States with different types of utility operating systems and implementations of utility-scale PV inverters. This report summarizes the project and findings from field demonstration at three utility sites.

  5. Implementation and Test of an Online Embedded Grid Impedance Estimation Technique for PV Inverters

    DEFF Research Database (Denmark)

    Asiminoaei, Lucian; Teodorescu, Remus; Blaabjerg, Frede

    2005-01-01

    New and stronger power quality requirements are issued due to the increased amount of photovoltaic (PV) installations. In this paper different methods are used for continuous grid monitoring in PV inverters. By injecting a noncharacteristic harmonic current and measuring the grid voltage response...

  6. Industry consultation on grid connection of small PV systems

    Energy Technology Data Exchange (ETDEWEB)

    Knight, J.; Thorneycroft, J.; Cotterell, M.; Gambro, S.

    2000-07-01

    This report presents the results of consultation within the PV industry and the electricity supply industry concerning guidelines for the connection of small PV systems to the electricity network. (author)

  7. Background information to the installers guide for small scale mains connected PV

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-07-01

    This report contains background information used by BRE, EA Technology, Halcrows and Sundog when compiling guidance for the UK's New and Renewable Energy Programme on the installation of small-scale photovoltaics (PV) in buildings. The report considers: relevant standards; general safety issues; fire and safety issues, including the fire resistance of PV modules; PV module ratings such as maximum voltage and maximum current; DC cabling; the DC disconnect; the DC junction box; fault analysis; general and AC side earthing; DC earthing; lightning and surge suppression; inverters; AC modules; AC systems; getting connection; mounting options; and installation issues.

  8. Mission Profile Based Sizing of IGBT Chip Area for PV Inverter Applications

    DEFF Research Database (Denmark)

    Shen, Yanfeng; Wang, Huai; Yang, Yongheng

    2016-01-01

    Maximizing the total energy generation is of importance for Photovoltaic (PV) plants. This paper proposes a method to optimize the IGBT chip area for PV inverters to minimize the annual energy loss of the active switches based on long-term operation conditions (i.e., mission profile). The design...... yearly mission profile. Simulation results are given to verify the thermal characteristics. Furthermore, a Monte Carlo based lifetime evaluation is presented to check the IGBT reliability. The proposed design method enables a reliability-oriented energy optimized sizing of active switches for PV inverter...

  9. Implementation and Test of On-line Embedded Grid Impedance Estimation for PV-inverters

    DEFF Research Database (Denmark)

    Asiminoaei, Lucian; Teodorescu, Remus; Blaabjerg, Frede

    2004-01-01

    to evaluate the grid impedance directly by the PV-inverter, providing a fast and low cost implementation. This principle theoretically provides a correct result of the grid impedance but when using it into the context of PV integration, different implementation issues strongly affect the quality...... of the results. This paper presents a new impedance estimation method including typical implementation problems encountered and it also presents adopted solutions for on-line grid impedance measurement. Practical tests on an existing PV-inverter validate the chosen solutions....

  10. Passive P-control of a grid-connected photovoltaic inverter

    NARCIS (Netherlands)

    Meza, C.; Jeltsema, D.; Scherpen, J. M. A.; Biel, D.

    2008-01-01

    A passive P-controller for a single-phase single-stage grid-connected photovoltaic inverter is presented. Explicit dependance of the PV array parameters on external unpredictable variables such as temperature and solar irradiance is avoided by extending the control scheme with a reference estimator.

  11. A Grid Connected Transformerless Inverter and its Model Predictive Control Strategy with Leakage Current Elimination Capability

    Directory of Open Access Journals (Sweden)

    J. Fallah Ardashir

    2017-06-01

    Full Text Available This paper proposes a new single phase transformerless Photovoltaic (PV inverter for grid connected systems. It consists of six power switches, two diodes, one capacitor and filter at the output stage. The neutral of the grid is directly connected to the negative terminal of the source. This results in constant common mode voltage and zero leakage current. Model Predictive Controller (MPC technique is used to modulate the converter to reduce the output current ripple and filter requirements. The main advantages of this inverter are compact size, low cost, flexible grounding configuration. Due to brevity, the operating principle and analysis of the proposed circuit are presented in brief. Simulation and experimental results of 200W prototype are shown at the end to validate the proposed topology and concept. The results obtained clearly verifies the performance of the proposed inverter and its practical application for grid connected PV systems.

  12. Improved Reliability of Single-Phase PV Inverters by Limiting the Maximum Feed-in Power

    DEFF Research Database (Denmark)

    Yang, Yongheng; Wang, Huai; Blaabjerg, Frede

    2014-01-01

    Grid operation experiences have revealed the necessity to limit the maximum feed-in power from PV inverter systems under a high penetration scenario in order to avoid voltage and frequency instability issues. A Constant Power Generation (CPG) control method has been proposed at the inverter level...... devices, allowing a quantitative prediction of the power device lifetime. A study case on a 3 kW single-phase PV inverter has demonstrated the advantages of the CPG control in terms of improved reliability.......Grid operation experiences have revealed the necessity to limit the maximum feed-in power from PV inverter systems under a high penetration scenario in order to avoid voltage and frequency instability issues. A Constant Power Generation (CPG) control method has been proposed at the inverter level....... The CPG control strategy is activated only when the DC input power from PV panels exceeds a specific power limit. It enables to limit the maximum feed-in power to the electric grids and also to improve the utilization of PV inverters. As a further study, this paper investigates the reliability performance...

  13. Development of Flexible Active Power Control Strategies for Grid-Connected Photovoltaic Inverters by Modifying MPPT Algorithms

    DEFF Research Database (Denmark)

    Sangwongwanich, Ariya; Yang, Yongheng; Blaabjerg, Frede

    2017-01-01

    As the penetration level of grid-connected PV systems increases, more advanced control functionality is demanded. In order to ensure smooth and friendly grid integration as well as enable more PV installations, the power generated by PV systems needs to be flexible and capable of: 1) limiting...... strategies for grid-connected PV inverters by modifying maximum power point tracking algorithms, where the PV power is regulated by changing the operating point of the PV system. In this way, no extra equipment is needed, being a cost-effective solution. Experiments on a 3-kW grid-connected PV system have...... the maximum feed-in power, 2) ensuring a smooth change rate, and 3) providing a power reserve. Besides, such flexible power control functionalities have to be achieved in a cost-effective way in order to ensure the competitiveness of solar energy. Therefore, this paper explores flexible active power control...

  14. Study on unitized inverter with photovoltaic grid-connected and stand-alone functions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Haining; Su, Jianhui; Ding, Ming [Hefei University of Technology, Hefei (China)

    2008-07-01

    The main circuit and algorithm of unitized single phase inverter are presented, in which photovoltaic (PV) grid-connected algorithm, independency sine inverter algorithm and storage battery charge administer are all integrated basing on DSP (Digital Signal Processor). The control system identifies utility failure initiatively and then switches to independency power supply automatically. The methods of charging battery are multiform. Basing on material term to use utility or solar array to charge can optimize charge efficiency, assure the capacitance of battery and prolong life-span of battery. In addition, some results are offered basing on the prototype of a 2.5kW single phase inverter. (orig.)

  15. Closed Loop Fuzzy Logic Controlled PV Based Cascaded Boost Five-Level Inverter System

    Science.gov (United States)

    Revana, Guruswamy; Kota, Venkata Reddy

    2018-04-01

    Recent developments in intelligent control methods and power electronics have produced PV based DC to AC converters related to AC drives. Cascaded boost converter and inverter find their way in interconnecting PV and Induction Motor. This paper deals with digital simulation and implementation of closed loop controlled five-level inverter based Photo-Voltaic (PV) system. The objective of this work is to reduce the harmonics using Multi Level Inverter based system. The DC output from the PV panel is boosted using cascaded-boost-converters. The DC output of these cascaded boost converters is applied to the bridges of the cascaded inverter. The AC output voltage is obtained by the series cascading of the output voltage of the two inverters. The investigations are done with Induction motor load. Cascaded boost-converter is proposed in the present work to produce the required DC Voltage at the input of the bridge inverter. A simple FLC is applied to CBFLIIM system. The FLC is proposed to reduce the steady state error. The simulation results are compared with the hardware results. The results of the comparison are made to show the improvement in dynamic response in terms of settling time and steady state error. Design procedure and control strategy are presented in detail.

  16. Grid Connected Solar PV System with SEPIC Converter Compared with Parallel Boost Converter Based MPPT

    OpenAIRE

    Bosco Raj, T. Ajith; Ramesh, R.; Maglin, J. R.; Vaigundamoorthi, M.; William Christopher, I.; Gopinath, C.; Yaashuwanth, C.

    2014-01-01

    The main objective of this work is to study the behaviour of the solar PV systems and model the efficient Grid-connected solar power system. The DC-DC MPPT circuit using chaotic pulse width modulation has been designed to track maximum power from solar PV module. The conversion efficiency of the proposed MPPT system is increased when CPWM is used as a control scheme. This paper also proposes a simplified multilevel (seven level) inverter for a grid-connected photovoltaic system. The primary g...

  17. Inverter sizing of grid-connected photovoltaic systems in the light of local solar resource distribution characteristics and temperature

    Energy Technology Data Exchange (ETDEWEB)

    Burger, Bruno [Fraunhofer-Institute for Solar Energy Systems ISE, Department of Electrical Energy Systems, Heidenhofstr. 2, 79110 Freiburg (Germany); Ruether, Ricardo [LABSOLAR-Laboratorio de Energia Solar, LabEEE-Laboratorio de Eficiencia Energetica em Edificacoes, Universidade Federal de Santa Catarina/UFSC, Caixa Postal 476, Florianopolis-SC 88040-900 (Brazil)

    2006-01-15

    Inverter sizing strategies for grid-connected photovoltaic (PV) systems often do not take into account site-dependent peculiarities of ambient temperature, inverter operating temperature and solar irradiation distribution characteristics. The operating temperature affects PV modules and inverters in different ways and PV systems will hardly ever have a DC output equal to or above their STC-rated nominal power. Inverters are usually sized with a nominal AC output power some 30% (sometimes even more) below the PV array nominal power. In this paper, we show that this practice might lead to considerable energy losses, especially in the case of PV technologies with high temperature coefficients of power operating at sites with cold climates and of PV technologies with low temperature coefficients of power operating at sites with warm climates and an energy distribution of sunlight shifted to higher irradiation levels. In energy markets where PV kWh are paid premium tariffs, like in Germany, energy yield optimization might result in a favorable payback of the extra capital invested in a larger inverter. This paper discusses how the time resolution of solar radiation data influences the correct sizing of PV plants. We demonstrate that using instant (10s) irradiation values instead of average hourly irradiation values leads to considerable differences in optimum inverter sizing. When calculating inverter yearly efficiency values using both, hourly averages and 1-min averages, we can show that with increased time resolution of solar irradiation data there are higher calculated losses due to inverter undersizing. This reveals that hourly averages hide important irradiation peaks that need to be considered. We performed these calculations for data sets from pyranometer readings from Freiburg (48{sup o}N, Germany) and Florianopolis (27{sup o}S, Brazil) to further show the peculiarities of the site-dependent distribution of irradiation levels and its effects on inverter sizing

  18. Hybrid PV/wind system with quinary asymmetric inverter without increasing DC-link number

    Directory of Open Access Journals (Sweden)

    Aida Baghbany Oskouei

    2016-06-01

    Full Text Available This paper suggests quinary asymmetric inverter with coupled inductors and transformer, and uses it in hybrid system including photovoltaic (PV and wind. This inverter produces twenty-five-level voltage in addition to merits of multilevel inverter, has only one DC source. Then, it is adequate for hybrid systems, which prevents increasing DC-link and makes control of system easy. Proposed structure also provides isolation in the system and the switch numbers are reduced in this topology compared with other multilevel structures. In this system, battery is used as backup, where PV and wind have complementary nature. The performance of proposed inverter and hybrid system is validated with simulation results using MATLAB/SIMULINK software and experimental results based PCI-1716 data acquisition system.

  19. CLOSED LOOP CONTROL OF EMBEDDED Z-SOURCE INVERTER WITH FUZZY CONTROLLER FOR SOLAR PV APPLICATIONS

    OpenAIRE

    Midde Mahesh*, K. Leleedhar Rao

    2017-01-01

    This paper proposes the use of Embedded Z –source inverter system with fuzzy controller for Solar Photo Voltaic (PV) applications with adjustable speed drives. Closed loop operation FUZZY control strategies of EZSI system are proposed. EZSI produces the same voltage gain as Z-source inverter (ZSI) but due to the DC sources embedded within the X- shaped impedance network, it has the added advantage of inherent source filtering capability and also reduced capacitor sizing. This can be achiev...

  20. Promotional drivers for grid-connected PV

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Polo, A.; Hass, R.; Suna, D.

    2009-03-15

    This report for the International Energy Agency (IEA) made by Task 10 of the Photovoltaic Power Systems (PVPS) programme takes a look at promotional measures for grid-connected photovoltaic systems. The mission of the Photovoltaic Power Systems Programme is to enhance the international collaboration efforts which accelerate the development and deployment of photovoltaic solar energy. The objective of Task 10 is stated as being to enhance the opportunities for wide-scale, solution-oriented application of photovoltaics in the urban environment. The paper discusses the core objective of this study which was to analyse the success of various governmental regulatory programs and governmental and non-governmental marketing programs for grid-connected PV systems. To meet this objective, a review of the most important past and current programs around the world was conducted. The theoretical bases of supply and demand are explained and the types of existing strategies are documented in a second Section. In Chapter 3, various programs around the world are described. Chapter 4 focuses on defining success criteria which will be used for the analysis of the programs. Finally, the major conclusions drawn complete this analysis.

  1. A Simple PV Inverter Power Factor Control Method Based on Solar Irradiance Variation

    DEFF Research Database (Denmark)

    Gökmen, Nuri; Hu, Weihao; Chen, Zhe

    2017-01-01

    There has been a significant rise in photovoltaic (PV) system installations throughout the last decade. This has posed some technical challenges to the distribution grid operators. Unfamiliar impacts of these relatively new energy sources now should be handled more comprehensively. The rigidity...... of these impacts mostly depends on PV penetration level, grid and weather characteristics as well as the interaction of load and generation. In this study, a reactive power control method is proposed benefitting from solar irradiance measurements in weather stations. Accordingly, power factors of PV inverters...

  2. A digital controlled PV-inverter with grid impedance estimation for ENS detection

    DEFF Research Database (Denmark)

    Asiminoaei, Lucian; Teodorescu, Remus; Blaabjerg, Frede

    2005-01-01

    in dispersed power generation networks. For instance, the knowledge of the utility impedance at the fundamental frequency can be used to detect a utility failure. A PV-inverter with this feature can anticipate a possible network problem and decouple it in time. This paper describes the digital implementation...

  3. A new high-efficiency single-phase transformerless PV inverter topology

    DEFF Research Database (Denmark)

    Kerekes, Tamas; Teodorescu, Remus; Rodriguez, Pedro

    2011-01-01

    There is a strong trend in the photovoltaic (PV) inverter technology to use transformerless topologies in order to acquire higher efficiencies combining with very low ground leakage current. In this paper a new topology, based on the H-Bridge with a new AC bypass circuit consisting in a diode...

  4. A New Method of On-line Grid Impedance Estimation for PV Inverter

    DEFF Research Database (Denmark)

    Teodorescu, Remus; Asiminoaei, Lucian; Blaabjerg, Frede

    2004-01-01

    for on-line measuring the grid impedance is presented. The presented method requires no extra hardware being accommodated by typical PV inverters, sensors and CPU, to provide a fast and low cost approach of on-line impedance measurement. By injecting a non-characteristic harmonic current and measuring...

  5. A New Family of Multilevel Grid Connected Inverters Based on Packed U Cell Topology.

    Science.gov (United States)

    Pakdel, Majid; Jalilzadeh, Saeid

    2017-09-29

    In this paper a novel packed U cell (PUC) based multilevel grid connected inverter is proposed. Unlike the U cell arrangement which consists of two power switches and one capacitor, in the proposed converter topology a lower DC power supply from renewable energy resources such as photovoltaic arrays (PV) is used as a base power source. The proposed topology offers higher efficiency and lower cost using a small number of power switches and a lower DC power source which is supplied from renewable energy resources. Other capacitor voltages are extracted from the base lower DC power source using isolated DC-DC power converters. The operation principle of proposed transformerless multilevel grid connected inverter is analyzed theoretically. Operation of the proposed multilevel grid connected inverter is verified through simulation studies. An experimental prototype using STM32F407 discovery controller board is performed to verify the simulation results.

  6. Evaluation of the Voltage Support Strategies for the Low Voltage Grid Connected PV

    DEFF Research Database (Denmark)

    Demirok, Erhan; Sera, Dezso; Teodorescu, Remus

    2010-01-01

    Admissible range of grid voltage is one of the strictest constraints for the penetration of distributed photovoltaic (PV) generators especially connection to low voltage (LV) public networks. Voltage limits are usually fulfilled either by network reinforcements or limiting of power injections from...... PVs. In order to increase PV penetration level further, new voltage support control functions for individual inverters are required. This paper investigates distributed reactive power regulation and active power curtailment strategies regarding the development of PV connection capacity by evaluation...... of reactive power efforts and requirement of minimum active power curtailment. Furthermore, a small scale experimental setup is built to reflect real grid interaction in the laboratory by achieving critical types of grid (weak and sufficiently stiff)....

  7. A single phase photovoltaic inverter control for grid connected system

    Indian Academy of Sciences (India)

    operation the PV inverter operates in voltage-controlled mode to maintain a constant amplitude and frequency of the voltage ..... 10W i.e. less than 8% of the maximum power, a step size of k2 is ...... ply/demand side management system.

  8. Single stage three level grid interactive MPPT inverter for PV systems

    International Nuclear Information System (INIS)

    Ozdemir, Saban; Altin, Necmi; Sefa, Ibrahim

    2014-01-01

    Highlights: • A three phase three-level NPC inverter for grid interactive PV systems is proposed. • A novel MPPT algorithm is introduced for single stage systems. • The proposed algorithm is robust with respect to parameter variations of PV system. • THD level is measured as 3.45% and it meets the international standards (<5%). • Total system efficiency is measured as 93.08%. - Abstract: In this study, three-phase, single stage neutral point clamped grid interactive inverter is designed and implemented. The reference current of the voltage source inverter is determined by maximum power point tracking sub-program in order to obtain maximum power from photovoltaic modules instantaneously. Proposed control is realized via TMS320F28335 32-bit floating point processor. The modified incremental conductance method is applied for maximum power point tracking; the PI regulator is used to control the inverter output current shape and level. Galvanic isolation is provided by a line frequency transformer that matches inverter output voltage to the grid voltage level and prevents DC current injection into the grid. Experimental results show that the designed inverter imports energy to the grid with unity power factor, total harmonic distortion level is 3.45% and this value is in the limits of the international standards. In addition, the total efficiency of the system is measured as 93.08%. The proposed system gets the maximum power from photovoltaic module and dispatches into the grid without using additional DC/DC converter

  9. An Enhanced Inverter Controller for PV Applications Using the dSPACE Platform

    Directory of Open Access Journals (Sweden)

    M. A. Hannan

    2010-01-01

    Full Text Available This paper presents the simulation modeling and prototype development of an inverter controller for photovoltaic (PV applications using the dSPACE DS1104 controller platform. The controller platform can link the simulation model developed in the MATLAB/SIMULINK environment to its prototype hardware. In the dSPACE controller, the voltage regulator controls the inverter by employing a proportional integral (PI controller and the Park transformation method to generate sinusoidal pulse-width modulation (SPWM signals. The SPWM signals switch the insulated gate bipolar transistor (IGBT to stabilize the 50-Hz sinusoidal AC output voltages of the inverter. The simulation was performed with a DC power supply that acts as the PV generator to supply the power to the inverter. The simulation model was then translated into the inverter prototype using the dSPACE platform and tested in the laboratory to prove the efficacy of the proposed controller. The experimental results for the inverter system demonstrated the feasibility of the proposed control strategy by maintaining the THD of the output voltage at 4.6%.

  10. Power system services provided by inverter connected distributed energy resources

    DEFF Research Database (Denmark)

    For the last few years there has been a significant increase of DER units in Denmark, of those units more and more are connected to the power system using inverters. These inverter connected units have the potential to support the electrical power system with various power system services. One...

  11. Basic study on dynamic reactive-power control method with PV output prediction for solar inverter

    Directory of Open Access Journals (Sweden)

    Ryunosuke Miyoshi

    2016-01-01

    Full Text Available To effectively utilize a photovoltaic (PV system, reactive-power control methods for solar inverters have been considered. Among the various methods, the constant-voltage control outputs less reactive power compared with the other methods. We have developed a constant-voltage control to reduce the reactive-power output. However, the developed constant-voltage control still outputs unnecessary reactive power because the control parameter is constant in every waveform of the PV output. To reduce the reactive-power output, we propose a dynamic reactive-power control method with a PV output prediction. In the proposed method, the control parameter is varied according to the properties of the predicted PV waveform. In this study, we performed numerical simulations using a distribution system model, and we confirmed that the proposed method reduces the reactive-power output within the voltage constraint.

  12. Isolated high-efficiency grid-connected de-central inverter for photovoltaic modules

    NARCIS (Netherlands)

    Vermulst, B.J.D.

    2012-01-01

    While an increasing number of photovoltaic (PV) systems is installed, those systems typically use central inverters. In practical cases, output-power differences between PV modules will cause these central-inverter-based systems not to achieve Maximum Power Point (MPP) for each PV module.

  13. Comparative Analysis of Inversors for Small PV Systems Grid Connected

    International Nuclear Information System (INIS)

    Sidrach de Cardona, M.; Ramirez, L.

    2001-01-01

    The energy produced by a grid connected photovoltaic system is a function of weather conditions, mainly available radiation and temperature, photovoltaic array efficiency and inverter characteristics. The results obtained in experimental measurements with four small grid-connected inverters are described in this work. The main goal is to know the inverter performance in real operation conditions. For this purpose a 2 kW photovoltaic system has been used. These results allow us to know both the inverter efficiency and its output power quality. The following parameters have been evaluated as a function of output inverter power: efficiency, point of maximum power tracking, intensity and voltage waveform, total harmonic distortion and harmonic values to 31 order, frequency, power factor and reactive power. Other interesting parameters like stand-by energy consumption and daily losses due to the inverter threshold have also been analyzed. The results allow us to know the inverter features as a function of its real work point. In our comparative study it is possible to observe remarkable differences between the inverters; these results show how important it is to have a unique standard for inverters to photovoltaic grid-connected systems. (Author) 10 refs

  14. Grid-connected photovoltaic power systems: survey of inverter and related protection equipments

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, T

    2002-12-15

    This report for the International Energy Agency (IEA) made by Task 5 of the Photovoltaic Power Systems (PVPS) programme reports on a survey made on inverter and related protection equipment. The mission of the Photovoltaic Power Systems Programme is to enhance the international collaboration efforts which accelerate the development and deployment of photovoltaic solar energy. Task 5 deals with issues concerning grid-interconnection and distributed PV power systems. This report summarises the data obtained from survey of recent inverter technology and inverter protection equipment for grid interconnected PV systems. The results are based on the surveys using a questionnaire to identify the current status of grid-interconnection inverters. This report is to serve as a reference for those interested in installing grid-connected PV systems, electric utility company personnel, manufacturers and researchers. The results of the survey are presented and discussed. Technical and financial data is reviewed and two appendices provide details on the results obtained and those institutions involved in the survey.

  15. Leakage Current Elimination of Four-Leg Inverter for Transformerless Three-Phase PV Systems

    DEFF Research Database (Denmark)

    Guo, Xiaoqiang; He, Ran; Jian, Jiamin

    2016-01-01

    Eliminating the leakage current is one of the most important issues for transformerless three phase photovoltaic (PV) systems. In this paper, the leakage current elimination of a three-phase four-leg PV inverter is investigated. With the common mode loop model established, the generation mechanism...... of the leakage current is clearly identified. Different typical carrier-based modulation methods and their corresponding common mode voltages are discussed. A new modulation strategy with Boolean logic function is proposed to achieve the constant common mode voltage for the leakage current reduction. Finally...

  16. Experimental Evaluation of Grid Support Enabled PV Inverter Response to Abnormal Grid Conditions: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, Austin; Martin, Gregory; Hurtt, James

    2017-05-08

    As revised interconnection standards for grid-tied photovoltaic (PV) inverters address new advanced grid support functions (GSFs), there is increasing interest in inverter performance in the case of abnormal grid conditions. The growth of GSF-enabled inverters has outpaced the industry standards that define their operation, although recently published updates to UL1741 with Supplement SA define test conditions for GSFs such as volt-var control, frequency-watt control, and volt-age/frequency ride-through, among others. A comparative experimental evaluation has been completed on four commercially available, three-phase PV inverters in the 24.0-39.8 kVA power range on their GSF capability and the effect on abnormal grid condition response. This study examines the impact particular GSF implementations have on run-on times during islanding conditions, peak voltages in load rejection overvoltage scenarios, and peak currents during single-phase and three-phase fault events for individual inverters. This report reviews comparative test data, which shows that GSFs have little impact on the metrics of interest in most tests cases.

  17. A PWM strategy for acoustic noise reduction for grid-connected single-phase inverters

    Energy Technology Data Exchange (ETDEWEB)

    Shao, R.; Guo, Z.; Chang, L. [New Brunswick Univ., Fredericton, NB (Canada). Dept. of Electrical and Computer Engineering

    2006-07-01

    This paper presented a newly proposed and improved pulse width modulation (PWM) strategy for grid-connected single-phase inverters. Small distributed generators using energy from renewable resources such as PV and wind systems typically use grid-connected single-phase inverters as voltage source inverters for good acoustic performance. PWM is generally applied in these inverters in order to achieve good waveforms of output current as required by interconnection standards. In routine simultaneous switching PWM methods, the current ripples through the inverter output filter inductor are at the carrier switching frequency, which is one of the major causes for inverter acoustic noise. The new PWM strategy effectively alleviates acoustic noise and improves output power quality. It is based on the principle of evenly splitting the switching of Insulated Gate Bipolar Transistors (IGBT) in each switching cycle among all IGBTs of the full bridge, thereby using a non-simultaneous mode of PWM which doubles the output current ripple frequency. This increases the inductor current ripple frequency to twice the carrier frequency. It is therefore possible to increase the current ripple frequency, or noise frequency into the range of ultrasonic which is inaudible to the human ear, without increasing the inverter's switching frequency to which the inverter's switching loss is proportional. In addition, this new PWM scheme can reduce the output current harmonics distortion and dc link current ripples. As such, lower capacitance in dc link capacitors and lower inductance of output inductor are needed. The improved PWM scheme was verified in a 3 kW grid-connected single-phase inverter. It was shown that the PWM strategy can be readily implemented with a digital signal processing microcontroller. 8 refs., 11 figs.

  18. New current control based MPPT technique for single stage grid connected PV systems

    International Nuclear Information System (INIS)

    Jain, Sachin; Agarwal, Vivek

    2007-01-01

    This paper presents a new maximum power point tracking algorithm based on current control for a single stage grid connected photovoltaic system. The main advantage of this algorithm comes from its ability to predict the approximate amplitude of the reference current waveform or power that can be derived from the PV array with the help of an intermediate variable β. A variable step size for the change in reference amplitude during initial tracking helps in fast tracking. It is observed that if the reference current amplitude is greater than the array capacity, the system gets unstable (i.e. moves into the positive slope region of the p-v characteristics of the array). The proposed algorithm prevents the PV system from entering the positive slope region of the p-v characteristics. It is also capable of restoring stability if the system goes unstable due to a sudden environmental change. The proposed algorithm has been tested on a new single stage grid connected PV configuration recently developed by the authors to feed sinusoidal current into the grid. The system is operated in a continuous conduction mode to realize advantages such as low device current stress, high efficiency and low EMI. A fast MPPT tracker with single stage inverter topology operating in CCM makes the overall system highly efficient. Specific cases of the system, operating in just discontinuous current mode and discontinuous current mode and their relative merits and demerits are also discussed

  19. Selective harmonic elimination strategy in eleven level inverter for PV system with unbalanced DC sources

    Science.gov (United States)

    Ghoudelbourk, Sihem.; Dib, D.; Meghni, B.; Zouli, M.

    2017-02-01

    The paper deals with the multilevel converters control strategy for photovoltaic system integrated in distribution grids. The objective of the proposed work is to design multilevel inverters for solar energy applications so as to reduce the Total Harmonic Distortion (THD) and to improve the power quality. The multilevel inverter power structure plays a vital role in every aspect of the power system. It is easier to produce a high-power, high-voltage inverter with the multilevel structure. The topologies of multilevel inverter have several advantages such as high output voltage, lower total harmonic distortion (THD) and reduction of voltage ratings of the power semiconductor switching devices. The proposed control strategy ensures an implementation of selective harmonic elimination (SHE) modulation for eleven levels. SHE is a very important and efficient strategy of eliminating selected harmonics by judicious selection of the firing angles of the inverter. Harmonics elimination technique eliminates the need of the expensive low pass filters in the system. Previous research considered that constant and equal DC sources with invariant behavior; however, this research extends earlier work to include variant DC sources, which are typical of lead-acid batteries when used in system PV. This Study also investigates methods to minimize the total harmonic distortion of the synthesized multilevel waveform and to help balance the battery voltage. The harmonic elimination method was used to eliminate selected lower dominant harmonics resulting from the inverter switching action.

  20. Research and development of peripheral technology for photovoltaic power systems. Development of inverter technology for photovoltaic (PV) system which is connected to the utility grid; Shuhen gijutsu no kenkyu kaihatsu. Fukusu kino tan`itsuka shuhen sochi no kenkyu kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Tatsuta, M [New Energy and Industrial Technology Development Organization, Tokyo (Japan)

    1994-12-01

    This paper reports the study results on development of integrated multifunctional peripheral equipment in fiscal 1994. (1) On development of inverters with no transformer, the following study results were obtained. Converter efficiency reached the target of 95.0% by using an improved general purpose IGBT as switching element of main circuit. Distortion factor of output current harmonics achieved 5% in total current distortion factor, and less than 3% in each order harmonic current one. In control of the DC part of output current, the target less than 0.3% was achieved by inserting a capacitor into detection signal circuit and by detection/correction control of current detector offset. Detection level of 100mA was achieved for DC grounding detection by installing a DC grounding detector in the DC input side of inverters. VCCI 1 level was also achieved for EMI measurement. (2) On development of integrated multifunctional peripheral equipment, evaluation test of the prototype equipment of 0.025m{sup 3} in volume and 17kg in mass was carried out. 3 figs., 1 tab.

  1. Online Grid Measurement and ENS Detection for PV Inverter Running on Highly Inductive Grid

    DEFF Research Database (Denmark)

    Timbus, Adrian Vasile; Teodorescu, Remus; Blaabjerg, Frede

    2004-01-01

    Photovoltaic (PV) and other sources of renewable energy are being used increasingly in grid-connected systems, for which stronger power quality requirements are being issued. Continuous grid monitoring should be considered so as to provide safe connections and disconnections from the grid...

  2. Modified Grid-Connected CSI for Hybrid PV/Wind Power Generation System

    Directory of Open Access Journals (Sweden)

    D. Amorndechaphon

    2012-01-01

    Full Text Available The principle of a power conditioning unit for hybrid PV/wind power generation system is proposed. The proposed power conditioner is based on the current source inverter (CSI topology. All energy sources are connected in parallel with a DC-bus through the modified wave-shaping circuits. To achieve the unity power factor at the utility grid, the DC-link current can be controlled via the wave-shaping circuits with the sinusoidal PWM scheme. In this work, the carrier-based PWM scheme is also proposed to minimize the utility current THD. The power rating of the proposed system can be increased by connecting more PV/wind modules through their wave-shaping circuits in parallel with the other modules. The details of the operating principles, the system configurations, and the design considerations are described. The effectiveness of the proposed CSI is demonstrated by simulation results.

  3. Performance Parameters for Grid-Connected PV Systems

    Energy Technology Data Exchange (ETDEWEB)

    Marion, B.; Adelstein, J.; Boyle, K.; Hayden, H.; Hammond, B.; Fletcher, T.; Canada, B.; Narang, D.; Shugar, D.; Wenger, H.; Kimber, A.; Mitchell, L.; Rich, G.; Townsend, T.

    2005-02-01

    The use of appropriate performance parameters facilitates the comparison of grid-connected photovoltaic (PV) systems that may differ with respect to design, technology, or geographic location. Four performance parameters that define the overall system performance with respect to the energy production, solar resource, and overall effect of system losses are the following: final PV system yield, reference yield, performance ratio, and PVUSA rating. These performance parameters are discussed for their suitability in providing desired information for PV system design and performance evaluation and are demonstrated for a variety of technologies, designs, and geographic locations. Also discussed are methodologies for determining system a.c. power ratings in the design phase using multipliers developed from measured performance parameters.The use of appropriate performance parameters facilitates the comparison of grid-connected photovoltaic (PV) systems that may differ with respect to design, technology, or geographic location. Four performance parameters that define the overall system performance with respect to the energy production, solar resource, and overall effect of system losses are the following: final PV system yield, reference yield, performance ratio, and PVUSA rating. These performance parameters are discussed for their suitability in providing desired information for PV system design and performance evaluation and are demonstrated for a variety of technologies, designs, and geographic locations. Also discussed are methodologies for determining system a.c. power ratings in the design phase using multipliers developed from measured performance parameters.

  4. Reduction of waveform distortion in grid-injection current from single-phase utility interactive PV-inverter

    International Nuclear Information System (INIS)

    Hamid, Muhammad Imran; Jusoh, Awang

    2014-01-01

    Highlights: • A reduction scheme for harmonics from utility interactive PV-inverter is proposed. • Single-phase conditioner with 3-phase expandability structure is used. • The single-phase conditioner in 3-phase structure work independently. • The scheme works effectively within overall operation range of the PV-inverter. • Conditioner in the scheme also improves the PV-inverter and plant’s utility factor. - Abstract: As the natural behavior of energy source and design characteristic, the current generated by a grid-interactive PV-inverter may contain harmonics. This distortion component will be carried on from the PV-inverter during injection power into the grid. Excessive harmonics in a grid will lead to a variety of power quality problems. This paper presents a distortion reduction scheme, utilizing a fed forward single-phase, generation-side power conditioner with a structure that can be expanded for use in a three-phase system and can work independently under imbalanced condition. Conditioner is placed in parallel with the photovoltaic plant and it functions to compensate the plant’s output current distortion, so that the total current flow to the grid is sinusoidal. This method also includes the implementation of a simpler control system for the conditioner, which consists of a combination of distortion current extraction, synchronization and a current control system, and realized through a TMS320F28335: a 150 MHz floating point DSP controller. Testing of the conditioner prototype, which was conducted on a real operation of a PV plant, showed that the scheme worked effectively within the overall operation range of the PV plant. This paper also discusses the potential of utility factor improvement of the PV-inverter and plant due to implementation of conditioner in the scheme

  5. Grid Connected Solar PV System with SEPIC Converter Compared with Parallel Boost Converter Based MPPT

    Directory of Open Access Journals (Sweden)

    T. Ajith Bosco Raj

    2014-01-01

    Full Text Available The main objective of this work is to study the behaviour of the solar PV systems and model the efficient Grid-connected solar power system. The DC-DC MPPT circuit using chaotic pulse width modulation has been designed to track maximum power from solar PV module. The conversion efficiency of the proposed MPPT system is increased when CPWM is used as a control scheme. This paper also proposes a simplified multilevel (seven level inverter for a grid-connected photovoltaic system. The primary goal of these systems is to increase the energy injected to the grid by keeping track of the maximum power point of the panel, by reducing the switching frequency, and by providing high reliability. The maximum power has been tracked experimentally. It is compared with parallel boost converter. Also this model is based on mathematical equations and is described through an equivalent circuit including a PV source with MPPT, a diode, a series resistor, a shunt resistor, and dual boost converter with active snubber circuit. This model can extract PV power and boost by using dual boost converter with active snubber. By using this method the overall system efficiency is improved thereby reducing the switching losses and cost.

  6. Harmonic currents Compensator Grid-Connected Inverter at the Microgrid

    DEFF Research Database (Denmark)

    Asuhaimi Mohd Zin, A.; Naderipour, A.; Habibuddin, M.H.

    2016-01-01

    The main challenge associated with the grid-connected inverter in distributed generation (DG) systems is to maintain the harmonic contents in output current below the specified values and compensates for unbalanced loads even when the grid is subject to disturbances such as harmonic distortion...... and unbalanced loads. To overcome these challenges, a current control strategy for a three-phase grid-connected inverter under unbalanced and nonlinear load conditions is presented. It enables grid-connected inverter by the proposed control method to inject balanced clean currents to the grid even when the local...... loads are unbalanced and/or nonlinear and also compensate of the harmonic currents and control the active and reactive power. The main advantage and objective of this method is to effectively compensate for the harmonic currents content of the grid current and microgrid without using any compensation...

  7. The German experience with grid-connected PV-systems

    International Nuclear Information System (INIS)

    Erge, T.; Hoffmann, V.U.; Kiefer, K.

    2001-01-01

    Grid-connected photovoltaics experienced increasing attention in Germany in recent years and are expected to face a major boost at the beginning of the new millennium. Highlights like the German 100,000-Roofs-Solar-Programme, PV programmes at schools financed by utilities and governments (e.g. 'SONNEonline' by PreussenElektra, 'Sonne in der Schule' by BMWi and 'Sonne in der Schule' by Bayernwerk) and large centralised installations of MW size ('Neue Messe Munchen' by Bayernwerk and 'Energiepark Mont-Cenis' by state Nordrhein-Westfalen, Stadtwerke Herne and European Union) count for the potential of grid-connected PV. Today in Germany a typical grid-connected PV installation of 1 kW nominal power produces average annual energy yields of 700 kWh (dependent on location and system components) and shows a high operating availability. The price per kWh from PV installations is still significantly higher than the price for conventional energy, but new funding schemes and cost models (like the large increase of feed-in tariff in Germany due to the Act on Granting Priority to Renewable Energy Sources in 2000) give optimism about the future. (Author)

  8. Grid-connected inverter for wind power generation system

    Institute of Scientific and Technical Information of China (English)

    YANG Yong; RUAN Yi; SHEN Huan-qing; TANG Yan-yan; YANG Ying

    2009-01-01

    In wind power generation system the grid-connected inverter is an important section for energy conversion and transmission, of which the performance has a direct influence on the entire wind power generation system. The mathematical model of the grid-connected inverter is deduced firstly. Then, the space vector pulse width modulation (SVPWM) is analyzed. The power factor can be controlled close to unity, leading or lagging, which is realized based on PI-type current controller and grid voltage vector-oriented control. The control strategy is verified by the simulation and experimental results with a good sinusoidal current, a small harmonic component and a fast dynamic response.

  9. High efficiency H6 single-phase transformerless grid-tied PV inverter with proposed modulation for reactive power generation

    Science.gov (United States)

    Almasoudi, Fahad M.; Alatawi, Khaled S.; Matin, Mohammad

    2017-08-01

    Implementation of transformerless inverters in PV grid-tied system offer great benefits such as high efficiency, light weight, low cost, etc. Most of the proposed transformerless inverters in literature are verified for only real power application. Currently, international standards such as VDE-AR-N 4105 has demanded that PV grid-tied inverters should have the ability of controlling a specific amount of reactive power. Generation of reactive power cannot be accomplished in single phase transformerless inverter topologies because the existing modulation techniques are not adopted for a freewheeling path in the negative power region. This paper enhances a previous high efficiency proposed H6 trnasformerless inverter with SiC MOSFETs and demonstrates new operating modes for the generation of reactive power. A proposed pulse width modulation (PWM) technique is applied to achieve bidirectional current flow through freewheeling state. A comparison of the proposed H6 transformerless inverter using SiC MOSFETs and Si MOSFTEs is presented in terms of power losses and efficiency. The results show that reactive power control is attained without adding any additional active devices or modification to the inverter structure. Also, the proposed modulation maintains a constant common mode voltage (CM) during every operating mode and has low leakage current. The performance of the proposed system verifies its effectiveness in the next generation PV system.

  10. Filter optimization of Si and SiC semiconductor-based H5 and Conergy-NPC transformerless PV inverters

    DEFF Research Database (Denmark)

    Saridakis, Stefanos; Koutroulis, Eftichios; Blaabjerg, Frede

    2013-01-01

    Single-phase transformerless Photovoltaic (PV) inverters are synthesized by combining available solutions in terms of the power section topology, power semiconductors manufacturing technology and structure of the output filter. A design method is presented in this paper for optimizing the power......C-based PV inverters will inject more energy into the electric grid, compared to the Si-based structures and enable the reduction of the output filter size, weight and cost. Employing an LLCL-type output filter and simultaneously reducing the cost of SiC power semiconductors to the level of their Si...

  11. Adaptive decoupled power control method for inverter connected DG

    DEFF Research Database (Denmark)

    Sun, Xiaofeng; Tian, Yanjun; Chen, Zhe

    2014-01-01

    an adaptive droop control method based on online evaluation of power decouple matrix for inverter connected distributed generations in distribution system. Traditional decoupled power control is simply based on line impedance parameter, but the load characteristics also cause the power coupling, and alter...

  12. Grid-Connected Inverter for Distributed Generation in Microgrid

    DEFF Research Database (Denmark)

    Naderipour, Amirreza; Miveh, Mohammad Reza; Guerrero, Josep M.

    for power generation. DGS units can operate in parallel to the main grid or in a Microgrid (MG) mode. An MG is a discrete energy system consisting of DGSs and loads capable of operating in parallel with, or independently from, the main grid. Meanwhile, Grid-Connected Inverters (GCIs) are typically used...

  13. Highlight of Grid-connected PV systems in administrative buildings in Egypt

    Directory of Open Access Journals (Sweden)

    Dina Said

    2017-03-01

    Full Text Available Solar energy applications are becoming increasingly common in Egypt. The abundant sunshine in Egypt, as well as the increasing competitiveness of solar energy systems including- but not limited to photovoltaic (PV, – predicts that these technologies could be weighed to be raised in Egypt.PV systems are installed on roof tiles or other parts of building structures to supplement grid utility, reduce electric bills, and provide emergency back–up energy. Moreover, they simultaneously reduce significant amounts of CO2 emissions. It is foreseen, a number of residential and public buildings in Egypt are using solar power to cut electric utility bills significantly. The approximately payback period to recover the investment costs for PV systems is up to about 5 years.  In addition, it is more economical to use PV system than grid utility systems. The two components that determine the total initial price of a grid- connected PV system are the modules and the balance of systems (BOS. The BOS includes different components such as mounting frames, inverters and site- specific installation hardware.The Government of Egypt (GOE has endorsed the deployment of PV systems through three approaches. It started with a prime minister decree to install PV projects on one-thousand of the governmental buildings. This was followed by as an initiative called "Shamsk ya Masr", and finally the Feed-in Tariff (FiT projects.Following the prime minster decree the Egyptian Electricity Holding Company (EEHC and its affiliated companies took the lead to install PV systems at the top roof of their administrative buildings and interconnect these systems to the electricity network where the suitable locations have been selected for mounting them. About 90 PV systems have been already mounted with about a capacity of 9 MW. On the other hand, "Shamsk ya Masr" has considered energy efficiency (EE so as to complement the PV systems, which will be installed on administrative

  14. Adaptive Hysteresis Band Current Control for Transformerless Single-Phase PV Inverters

    DEFF Research Database (Denmark)

    Vázquez, Gerardo; Rodriguez, Pedro; Ordoñez, Rafael

    2009-01-01

    Current control based on hysteresis algorithms are widely used in different applications, such as motion control, active filtering or active/reactive power delivery control in distributed generation systems. The hysteresis current control provides to the system a fast and robust dynamic response......, and requires a simple implementation in standard digital signal platforms. On the other hand, the main drawback of classical hysteresis current control lies in the fact that the switching frequency is variable, as the hysteresis band is fixed. In this paper a variable band hysteresis control algorithm...... different single-phase PV inverter topologies, by means of simulations performed with PSIM. In addition, the behavior of the thermal losses when using each control structure in such converters has been studied as well....

  15. RTDS implementation of an improved sliding mode based inverter controller for PV system.

    Science.gov (United States)

    Islam, Gazi; Muyeen, S M; Al-Durra, Ahmed; Hasanien, Hany M

    2016-05-01

    This paper proposes a novel approach for testing dynamics and control aspects of a large scale photovoltaic (PV) system in real time along with resolving design hindrances of controller parameters using Real Time Digital Simulator (RTDS). In general, the harmonic profile of a fast controller has wide distribution due to the large bandwidth of the controller. The major contribution of this paper is that the proposed control strategy gives an improved voltage harmonic profile and distribute it more around the switching frequency along with fast transient response; filter design, thus, becomes easier. The implementation of a control strategy with high bandwidth in small time steps of Real Time Digital Simulator (RTDS) is not straight forward. This paper shows a good methodology for the practitioners to implement such control scheme in RTDS. As a part of the industrial process, the controller parameters are optimized using particle swarm optimization (PSO) technique to improve the low voltage ride through (LVRT) performance under network disturbance. The response surface methodology (RSM) is well adapted to build analytical models for recovery time (Rt), maximum percentage overshoot (MPOS), settling time (Ts), and steady state error (Ess) of the voltage profile immediate after inverter under disturbance. A systematic approach of controller parameter optimization is detailed. The transient performance of the PSO based optimization method applied to the proposed sliding mode controlled PV inverter is compared with the results from genetic algorithm (GA) based optimization technique. The reported real time implementation challenges and controller optimization procedure are applicable to other control applications in the field of renewable and distributed generation systems. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  16. A Single Phase Doubly Grounded Semi-Z-Source Inverter for Photovoltaic (PV Systems with Maximum Power Point Tracking (MPPT

    Directory of Open Access Journals (Sweden)

    Tofael Ahmed

    2014-06-01

    Full Text Available In this paper, a single phase doubly grounded semi-Z-source inverter with maximum power point tracking (MPPT is proposed for photovoltaic (PV systems. This proposed system utilizes a single-ended primary inductor (SEPIC converter as DC-DC converter to implement the MPPT algorithm for tracking the maximum power from a PV array and a single phase semi-Z-source inverter for integrating the PV with AC power utilities. The MPPT controller utilizes a fast-converging algorithm to track the maximum power point (MPP and the semi-Z-source inverter utilizes a nonlinear SPWM to produce sinusoidal voltage at the output. The proposed system is able to track the MPP of PV arrays and produce an AC voltage at its output by utilizing only three switches. Experimental results show that the fast-converging MPPT algorithm has fast tracking response with appreciable MPP efficiency. In addition, the inverter shows the minimization of common mode leakage current with its ground sharing feature and reduction of the THD as well as DC current components at the output during DC-AC conversion.

  17. Comparative analysis of the performance of string and central inverter topology at a large PV utility plant with varying topography

    DEFF Research Database (Denmark)

    Paasch, Kasper; Nymand, Morten; Kjær, Søren Bækhøj

    2015-01-01

    MPPT) and a series of small central inverters (60 kW, 1 MPPT) in the same PV plant under varying irradiation conditions and also including the potential detrimental effect of the horizontally tilt of the solar panels due to area topography variation. It has been shown that the gain from using multiple...

  18. A transformerless single-phase symmetrical Z-source HERIC inverter with reduced leakage currents for PV systems

    DEFF Research Database (Denmark)

    Li, Kerui; Shen, Yanfeng; Yang, Yongheng

    2018-01-01

    and thus low leakage currents in PV applications. The symmetric Z-source HERIC inverter requires two extra active switches. Nevertheless, the operation frequency of the two switches is the line frequency, leading to negligible losses. More importantly, the performance in terms of low leakage currents...... and harmonics is improved. Experimental tests are performed to validate the analysis and performance of the proposed system....

  19. Three-Phase PV CHB Inverter for a Distributed Power Generation System

    Directory of Open Access Journals (Sweden)

    Pierluigi Guerriero

    2016-10-01

    Full Text Available This work deals with the design of a three-phase grid-tied photovoltaic (PV cascade H-bridge inverter for distributed power conversion. The power balancing among the phases must be properly addressed. In fact, an intra-phase power imbalance—arising from uneven irradiance and temperature conditions—generates a per-phase power imbalance. This latter can be compensated by the injection of a proper zero-sequence voltage, while the intra-phase balance is ensured by means of a hybrid modulation method which is able to guarantee the handling of unequal DC (Direct Current sources, stable circuit operation, and maximization of PV power production. The digital controller is developed and tested in Matlab/Simulink environment integrated with XSG (Xilinx System Generator, thus allowing an easy transfer on a field-programmable gate array (FPGA platform and accurately describing the behavior of a real hardware implementation. Thus, numerical results have been considered to prove the effectiveness of the proposed approach.

  20. Power Control Flexibilities for Grid-Connected Multi-Functional Photovoltaic Inverters

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede; Wang, Huai

    2016-01-01

    and intelligent services, such as fault ride-through and reactive power compensation, is the key to attain higher utilisation of solar PV energy. Such functionalities for the future PV inverters can contribute to reduced cost of energy, and thus enable more cost-effective PV installations. To implement...... the advanced features, a flexible power controller is developed in this study, which can be configured in the PV inverter and flexibly change from one to another mode during operation. Based on the single-phase PQ theory, the control strategy offers the possibilities to generate appropriate references...... for the inner current control loop. The references depend on system conditions and also specific demands from both system operators and prosumers. Besides, this power control strategy can be implemented in commercial PV inverters as a standardised function, and also the operation modes can be achieved online...

  1. Improved Droop Control Strategy for Grid-Connected Inverters

    DEFF Research Database (Denmark)

    Abusara, Mohammad; Sharkh, Suleiman; Guerrero, Josep M.

    2015-01-01

    An improved control strategy for grid-connected inverters within microgrids is presented in this paper. The strategy is based on the classical P-ω and Q-V droop method. The improvement in the proposed control strategy is twofold: Firstly, the transient response of the droop controller is improved...... by replacing the traditional method of measuring average power, which is based on using a first order low pass filter, by a real time integration filter. This is shown to reduce the imported transient energy when connecting to the grid. Secondly, the steady state output current quality is improved by utilising...... a virtual inductance, which is shown to reject grid voltage harmonics disturbance and thus improve the output current THD. A small signal model of the inverter based on the transfer function approach is developed to analyse is stability and determine droop gains. Simulation and experimental results...

  2. Modeling Of Components Of A Photovoltaic System With Voltage Inverter For Connection To The Electrical Grid

    International Nuclear Information System (INIS)

    Ferreira, Andreza C.; Blasques, Luis C. M.; Galhardo, Marcos A. B.; Pinho, João T.

    2017-01-01

    This paper describes the modeling of the electrical equipment and control mechanisms used in the power conditioning system of a grid-connected photovoltaic system (GCPVS), such as the photovoltaic generator, the DC/DC converter, the voltage inverter with PWM control, its output filter, as well as the converter controls and their functionalities, and the interconnection of the system with the distribution grid and load. In addition to the modeling of the grid-tie inverter, the main equipment of the power conditioning system, this paper describes the synchronization form of the photovoltaic (PV) generation with the electricity distribution grid, considering the power injection control method, the maximum power point tracking technique for maximizing the energy supplied by the photovoltaic generator, and the complete topology of the proposed PV system. The main objective is to provide a computational model capable of simulating the behavior of the GCPVS elements, varying the climatic conditions and the power demand on the AC side, presenting consistent results for different operating conditions, such as variations of climatic parameters (solar irradiance, wind speed, and ambient temperature) and load. In these cases, it is possible to evaluate the behavior of the system, sometimes supplying both the active and reactive power of the load, according to the need. (author)

  3. Inrush Transient Current Analysis and Suppression of Photovoltaic Grid-Connected Inverters During Voltage Sag

    DEFF Research Database (Denmark)

    Li, Zhongyu; Zhao, Rende; Xin, Zhen

    2016-01-01

    The Inrush Transient Current (ITC) in the output of the photovoltaic grid-connected inverters is usually generated when grid voltage sag occurs, which can trigger the protection of the grid-connected inverters, and even destroy the semiconductor switches. Then, the grid-connected inverters...

  4. Reliability assessment of single-phase grid-connected PV microinverters considering mission profile and uncertainties

    DEFF Research Database (Denmark)

    Zare, Mohammad Hadi; Mohamadian, Mustafa; Wang, Huai

    2017-01-01

    Microinverters usually connect a PV panel to a Single-phase power grid. In such system, the input power is constant while the output power oscillates twice the line frequency. Thus, the input and output power differences should be stored in a storage component, which is typically an electrolytic ...... irritation of two different places on the micro inverter lifetime is studied....... capacitor. However, electrolytic capacitors are usually blamed for their short lifetime. Recently, some active power decoupling methods are introduced in the literature which can takes advantage of high reliable film capacitors. However, some extra switches and diodes are added to the microinverter which...... can influence the microinverter lifetime. This paper investigates the microinverter reliability according to mission profile where it is installed. To get more accurate results, uncertainties in both lifetime model and manufacturing process are considered. The effect of ambient temperature and solar...

  5. Analysis to Inform CA Grid Integration Rules for PV: Final Report on Inverter Settings for Transmission and Distribution System Performance

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Jeff [Electric Power Research Inst. (EPRI), Palo Alto, CA (United States); Rylander, Matthew [Electric Power Research Inst. (EPRI), Palo Alto, CA (United States); Boemer, Jens [Electric Power Research Inst. (EPRI), Palo Alto, CA (United States); Broderick, Robert Joseph [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Reno, Matthew J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Mather, Barry [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-09-01

    The fourth solicitation of the California Solar Initiative (CSI) Research, Development, Demonstration and Deployment (RD&D) Program established by the California Public Utilities Commission (CPUC) supported the Electric Power Research Institute (EPRI), National Renewable Energy Laboratory (NREL), and Sandia National Laboratories (SNL) with data provided from Pacific Gas and Electric (PG&E), Southern California Edison (SCE), and San Diego Gas and Electric (SDG&E) conducted research to determine optimal default settings for distributed energy resource advanced inverter controls. The inverter functions studied are aligned with those developed by the California Smart Inverter Working Group (SIWG) and those being considered by the IEEE 1547 Working Group. The advanced inverter controls examined to improve the distribution system response included power factor, volt-var, and volt-watt. The advanced inverter controls examined to improve the transmission system response included frequency and voltage ride-through as well as Dynamic Voltage Support. This CSI RD&D project accomplished the task of developing methods to derive distribution focused advanced inverter control settings, selecting a diverse set of feeders to evaluate the methods through detailed analysis, and evaluating the effectiveness of each method developed. Inverter settings focused on the transmission system performance were also evaluated and verified. Based on the findings of this work, the suggested advanced inverter settings and methods to determine settings can be used to improve the accommodation of distributed energy resources (PV specifically). The voltage impact from PV can be mitigated using power factor, volt-var, or volt-watt control, while the bulk system impact can be improved with frequency/voltage ride-through.

  6. Current control loop of 3-phase grid-connected inverter

    International Nuclear Information System (INIS)

    Jabbar, A F; Mansor, M

    2013-01-01

    This paper presents a comparative study of current control loop in 3-phase inverter which is used to control the active and reactive output power. Generally, current control loop, power control loop and phase lock-loop are the conventional parameters that can be found in an inverter system controlled by the conventional linear control type, for instance proportional (P), integral (I) and derivative (D). If the grid remains stable throughout the day, PID control can be use. However variation of magnitude, frequency, voltage dips, transient, and other related power quality issues occur in a 3-phase grid often affects the control loop. This paper aims to provide an overall review on the available current control techniques used in grid connected system.

  7. Power control flexibilities for grid-connected multi-functional photovoltaic inverters

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede; Wang, Huai

    2014-01-01

    to reduced cost of energy. To implement the advanced features, a flexible power controller is developed in this paper, which can be configured in the PV inverter and flexibly be changed from one to another. This power control strategy is based on the single-phase PQ theory, and it offers the possibilities...... of ancillary and intelligent services, like Low Voltage Ride-Through (LVRT), reactive power compensation, and reliability-oriented thermal management/control by PV systems is a key to attain higher utilization of solar energy. Those essential functionalities for the future PV inverters can contribute...... to generate appropriate references for the inner current control loop. The references depend on the system conditions and also specific demands from both system operators and customers. Besides, this power control strategy can be implemented in a commercial PV inverter as standardized functions, and also...

  8. A Review on Current Reference Calculation of Three-Phase Grid-Connected PV Converters under Grid Faults

    DEFF Research Database (Denmark)

    Afshari, Ehsan; Moradi, Gholam Reza; Yang, Yongheng

    2017-01-01

    Unbalanced grid voltage dips may lead to unbalanced non-sinusoidal current injections, dc-link voltage oscillations, and active and/or reactive power oscillations with twice the grid fundamental frequency in three-phase grid-connected Photovoltaic (PV) systems. Double grid frequency oscillations...... of the most important issues that should be coped with for a reliable operation of grid-connected converters under unbalanced grid faults. Accordingly, this paper reviews the existing CRC methods and presents a current reference generation method, which can have 16 unique modes. Issues are also investigated...... at the dc-link of the conventional two-stage PV inverters can further deteriorate the dc-link capacitor, which is one of the most life-limiting components in the system. Proper controls of these converters may efficiently address this problem. In those solutions, Current Reference Calculation (CRC) is one...

  9. Performance analysis of a 11.2 kWp roof top grid-connected PV system in Eastern India

    Directory of Open Access Journals (Sweden)

    Renu Sharma

    2017-11-01

    Full Text Available Barren land and roof tops of buildings are being increasingly used worldwide to install solar panels for generating electricity. One such step has been taken by Siksha ‘O’Anusandhan University, Bhubaneswar (Latitude 20.24° N and Longitude 80.85° E by installing a 11.2 kWp grid connected solar power system during February, 2014. This PV system is tilted at an angle of 21° on the top floor of a 25 metre height building. This system was installed This paper presents the results of this grid connected photovoltaic system which was monitored between September 2014 to August 2015. The entire electricity generated by the system was fed into the state grid. The different parameters of the system studied include PV module efficiency, array yield, final yield, inverter efficiency and performance ratio of the system. The total energy generated during this period was found to be 14.960 MWh and the PV module efficiency, inverter efficiency and performance ratio were found to be 13.42%, 89.83% and 0.78 respectively.

  10. The Frequency Fluctuation Impact Analysis for Droop Controlled Grid-connecting Inverter in Microgrid

    DEFF Research Database (Denmark)

    Wei, Feng; Sun, Kai; Guan, Yajuan

    2016-01-01

    No matter with PV or batteries as DC source, the droop controlled grid-connecting inverter (DC-GCI) has been widely used in microgrid. As the bandwidth of the outer active and reactive power control loop is designed to be much slower when comparing to the inner voltage/current loop of the DCGCI......, and the low equivalent impedance presented by the system, the power disturbance resulting from grid’s frequency fluctuation of DC-GCI may not be compensated by the outer power controller in time. Therefore, the frequency stability of the system mainly depends on its voltage tracking performance dominated...... by the inner loop’s voltage control strategy. In this paper, three widely used inner voltage/current control schemes, including PI controller in the synchronous rotating reference frame, and the PR controller with fixed and dynamic resonant frequency in the stationary frame have been discussed. The small...

  11. Robust Droop Control of Grid-Connected Inverters

    DEFF Research Database (Denmark)

    Elkayam, Moria; Kuperman, Alon; Guerrero, Josep M.

    2016-01-01

    The use of distributed generation in microgrid systems is becoming a popular way to provide a reliable source of electricity to critical loads. Droop control techniques are used in power systems for the synchronization of grid-connected inverters by local measurements of active and reactive powers....... Despite the benefits of distributed generation, the drawback is that large grid-side impedance steps can cause a system to become unstable. A robust control method based on disturbance observer is proposed in this paper. When the proposed robust controller is utilized, closed loop performance remains...

  12. Performance analysis of the Single-Phase Grid-Connected Inverter of a photovoltaic system in water and wind applications

    Directory of Open Access Journals (Sweden)

    Borkowski Dariusz

    2016-01-01

    Full Text Available Single-phase grid connected inverters are nowadays broadly developed and tested in various types of applications especially in photovoltaic systems. The main aim of the inverter control strategy is to extract the maximum energy from the PV system which corresponds to the maximum power at certain conditions. However, the MPPT methods are also important in other renewable energy conversion systems. This paper analyses the performance of a commercially available photovoltaic inverter in water and wind systems. Presented models are implemented in a laboratory test bench in the form of torque characteristics realised by an induction motor fed by the inverter with vector control. The parameters are scaled into relative variables to provide a proper performance comparison. Presented tests include step response to assess the performance of a system dynamic. The dynamic tests showed a fast response of the investigated systems. The MPPT tracking accuracy tested under realistic profiles is similar for both cases: 98% and 96% respectively for the wind and water systems. These results prove the satisfactory performance of the MPPT of the PV microinverter in these applications.

  13. A Sensorless Power Reserve Control Strategy for Two-Stage Grid-Connected PV Systems

    OpenAIRE

    Sangwongwanich, Ariya; Yang, Yongheng; Blaabjerg, Frede

    2017-01-01

    Due to the still increasing penetration of grid-connected Photovoltaic (PV) systems, advanced active power control functionalities have been introduced in grid regulations. A power reserve control, where namely the active power from the PV panels is reserved during operation, is required for grid support. In this paper, a cost-effective solution to realize the power reserve for two-stage grid-connected PV systems is proposed. The proposed solution routinely employs a Maximum Power Point Track...

  14. Power control based on particle swarm optimization of grid-connected inverter for hybrid renewable energy system

    International Nuclear Information System (INIS)

    García-Triviño, Pablo; Gil-Mena, Antonio José; Llorens-Iborra, Francisco; García-Vázquez, Carlos Andrés; Fernández-Ramírez, Luis M.; Jurado, Francisco

    2015-01-01

    Highlights: • Three PSO-based PI controllers for a grid-connected inverter were presented. • Two online PSO-based PI controllers were compared with an offline PSO-tuned PI. • The HRES and the inverter were evaluated under power changes and grid voltage sags. • Online ITAE-based PSO reduced ITAE (current THD) by 15.24% (5.32%) versus offline one. - Abstract: This paper is focused on the study of particle swarm optimization (PSO)-based PI controllers for the power control of a grid-connected inverter supplied from a hybrid renewable energy system. It is composed of two renewable energy sources (wind turbine and photovoltaic – PV – solar panels) and two energy storage systems (battery and hydrogen system, integrated by fuel cell and electrolyzer). Three PSO-based PI controllers are implemented: (1) conventional PI controller with offline tuning by PSO algorithm based on the integral time absolute error (ITAE) index; (2) PI controllers with online self-tuning by PSO algorithm based on the error; and (3) PI controllers with online self-tuning by PSO algorithm based on the ITAE index. To evaluate and compare the three controllers, the hybrid renewable energy system and the grid-connected inverter are simulated under changes in the active and reactive power values, as well as under a grid voltage sag. The results show that the online PSO-based PI controllers that optimize the ITAE index achieves the best response

  15. PV String to 3-Phase Inverter with Highest Voltage Capabilities, Highest Efficiency and 25 Year Lifetime: Final Technical Report, November 7, 2011 - November 6, 2012

    Energy Technology Data Exchange (ETDEWEB)

    West, R.

    2012-12-01

    Final report for Renewable Power Conversion. The overall objective of this project was to develop a prototype PV inverter which enables a new utility-scale PV system approach where the cost, performance, reliability and safety benefits of this new approach have the potential to make all others obsolete.

  16. Low voltage ride-through of single-phase transformerless photovoltaic inverters

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede; Wang, Huai

    2013-01-01

    Transformerless photovoltaic (PV) inverters are going to be more widely adopted in order to achieve high efficiency, as the penetration level of PV systems is continuously booming. However, problems may arise in highly PV-integrated distribution systems. For example, a sudden stoppage of all PV...... discussed. The selected inverters are the full-bridge inverter with bipolar modulation, full-bridge inverter with DC bypass and the Highly Efficient and Reliable Inverter Concept (HERIC). A 1 kW single-phase grid-connected PV system is analyzed to verify the discussions. The tests confirmed that, although...

  17. Low Voltage Ride-Through of Single-Phase Transformerless Photovoltaic Inverters

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede; Wang, Huai

    2014-01-01

    Transformerless photovoltaic (PV) inverters are going to be more widely adopted in order to achieve high efficiency, as the penetration level of PV systems is continuously booming. However, problems may arise in highly PV-integrated distribution systems. For example, a sudden stoppage of all PV...... are also discussed. The selected inverters are the full-bridge inverter with bipolar modulation, full-bridge inverter with DC bypass and the Highly Efficient and Reliable Inverter Concept (HERIC). A 1 kW singlephase grid-connected PV system is analyzed to verify the discussions. The tests confirmed that...

  18. Modeling and Grid impedance Variation Analysis of Parallel Connected Grid Connected Inverter based on Impedance Based Harmonic Analysis

    DEFF Research Database (Denmark)

    Kwon, JunBum; Wang, Xiongfei; Bak, Claus Leth

    2014-01-01

    This paper addresses the harmonic compensation error problem existing with parallel connected inverter in the same grid interface conditions by means of impedance-based analysis and modeling. Unlike the single grid connected inverter, it is found that multiple parallel connected inverters and grid...... impedance can make influence to each other if they each have a harmonic compensation function. The analysis method proposed in this paper is based on the relationship between the overall output impedance and input impedance of parallel connected inverter, where controller gain design method, which can...

  19. PWM Regulation of Grid-Tied PV System on the Base of Photovoltaic-Fed Diode-Clamped Inverters

    Directory of Open Access Journals (Sweden)

    Oleschuk V.I.

    2015-12-01

    Full Text Available Investigation of grid-tied photovoltaic system on the base of two diode-clamped inverters, controlled by specific algorithms of pulse-width modulation (PWM, has been done. This system includes two strings of photovoltaic panels feeding two diode-clamped inverters. The outputs of inverters are connected with the corresponding windings on the primary side of three-phase transformer, connected with a grid. In order to reduce phase voltage distortion and to increase efficiency of operation of the system, special scheme of control and modulation of inverters has been used, providing minimization of common-mode voltages and voltage waveforms symmetries under different operating conditions. Detailed simulation of processes in this photovoltaic-fed power conversion system has been executed. The results of simulations verify good performance of photovoltaic system regulated in accordance with specific strategy of control and modulation.

  20. Resonance Interaction of Multi-Parallel Grid-Connected Inverters with LCL Filter

    DEFF Research Database (Denmark)

    Lu, Minghui; Wang, Xiongfei; Loh, Poh Chiang

    2017-01-01

    This letter investigates the resonance characteristics and stability problem caused by the interactions of multiparallel LCL-filtered inverters. Compared to single grid-connected inverter, the multiinverter system presents a more challenging resonance issue, where the inverter interactions may...... excite multiple resonances at various frequencies. This letter proposes a modeling and analysis method based on the current separation scheme. It reveals that an interactive resonant current that circulates between the paralleled three-phase inverters may arise, depending on the current distribution...

  1. Performance of a 34 kWp grid-connected PV system in Indonesia - A comparison of tropical and European PV systems

    NARCIS (Netherlands)

    Veldhuis, A.J.; Reinders, Angelina H.M.E.

    2014-01-01

    We analysed a monitored grid-connected PV system of 34 kWp in Indonesia to investigate the performance of PV systems in tropical climates. The PV system has been installed in Jayapura, the capital of the Province of Papua, Indonesia, by the beginning of 2012. Due to the aged gensets and frequent

  2. Improving Performance of LVRT Capability in Single-phase Grid-tied PV Inverters by a Model Predictive Controller

    DEFF Research Database (Denmark)

    Zangeneh Bighash, Esmaeil; Sadeghzadeh, Seyed Mohammad; Ebrahimzadeh, Esmaeil

    2018-01-01

    dynamic response and stability. To fill in this gap, this paper presents a fast and robust current controller based on a Model-Predictive Control (MPC) for single-phase PV inverters in other to deal with the LVRT operation. In order to confirm the effectiveness of the proposed controller, results...... the voltage sag period is short, a fast dynamic performance along with a soft behavior of the controller is the most important issue in the LVRT duration. Recently, some methods like Proportional Resonant (PR) controllers, have been presented to control the single phase PV systems in LVRT mode. However......, these methods have had uncertainties in respect their contribution in LVRT mode. In PR controllers, a fast dynamic response can be obtained by tuning the gains of PR controllers for a high bandwidth, but typically the phase margin is decreased. Therefore, the design of PR controllers needs a tradeoff between...

  3. Grid-connected to/from off-grid transference for micro-grid inverters

    OpenAIRE

    Heredero Peris, Daniel; Chillón Antón, Cristian; Pages Gimenez, Marc; Gross, Gabriel Igor; Montesinos Miracle, Daniel

    2013-01-01

    This paper compares two methods for controlling the on-line transference from connected to stand-alone mode and vice versa in converters for micro-grids. The first proposes a method where the converter changes from CSI (Current Source Inverter) in grid-connected mode to VSI (Voltage Source Inverter) in off-grid. In the second method, the inverter always works as a non-ideal voltage source, acting as VSI, using AC droop control strategy.

  4. Disturbance estimator based predictive current control of grid-connected inverters

    OpenAIRE

    Al-Khafaji, Ahmed Samawi Ghthwan

    2013-01-01

    ABSTRACT: The work presented in my thesis considers one of the modern discrete-time control approaches based on digital signal processing methods, that have been developed to improve the performance control of grid-connected three-phase inverters. Disturbance estimator based predictive current control of grid-connected inverters is proposed. For inverter modeling with respect to the design of current controllers, we choose the d-q synchronous reference frame to make it easier to understand an...

  5. A Sensorless Power Reserve Control Strategy for Two-Stage Grid-Connected PV Systems

    DEFF Research Database (Denmark)

    Sangwongwanich, Ariya; Yang, Yongheng; Blaabjerg, Frede

    2017-01-01

    Due to the still increasing penetration of grid-connected Photovoltaic (PV) systems, advanced active power control functionalities have been introduced in grid regulations. A power reserve control, where namely the active power from the PV panels is reserved during operation, is required for grid...... support. In this paper, a cost-effective solution to realize the power reserve for two-stage grid-connected PV systems is proposed. The proposed solution routinely employs a Maximum Power Point Tracking (MPPT) control to estimate the available PV power and a Constant Power Generation (CPG) control...... performed on a 3-kW two-stage single-phase grid-connected PV system, where the power reserve control is achieved upon demands....

  6. Single Phase Transformer-less Buck-Boost Inverter with Zero Leakage Current for PV Systems

    DEFF Research Database (Denmark)

    Mostaan, Ali; Abdelhakim, Ahmed; N. Soltani, Mohsen

    2017-01-01

    In this paper, a novel single-stage single-phase transformer-less buck-boost inverter is proposed, in which a reduced number of passive components is used. The proposed inverter combines the conventional buck, boost, and buck-boost converters in one converter in order to obtain a sinusoidal output...

  7. Design and comparison of a 10-kW interleaved boost converter for PV application using Si and SiC devices

    NARCIS (Netherlands)

    Chandra Mouli, G.R.; Schijffelen, Jos H.; Bauer, P.; Zeman, M.

    2017-01-01

    Grid-connected photovoltaic (PV) inverters have a dc/dc converter connected to the PV for executing the maximum power point tracking. The design of an interleaved boost converter (IBC) with three switching legs for a 10-kW PV inverter is presented in this paper. This paper shows how the use of

  8. Status and Needs of Power Electronics for Photovoltaic Inverters

    Science.gov (United States)

    Qin, Y. C.; Mohan, N.; West, R.; Bonn, R.

    2002-06-01

    Photovoltaics is the utility connected distributed energy resource (DER) that is in widespread use today. It has one element, the inverter, which is common with all DER sources except rotating generators. The inverter is required to transfer dc energy to ac energy. With all the DER technologies, (solar, wind, fuel cells, and microturbines) the inverter is still an immature product that will result in reliability problems in fielded systems. Today, the PV inverter is a costly and complex component of PV systems that produce ac power. Inverter MTFF (mean time to first failure) is currently unacceptable. Low inverter reliability contributes to unreliable fielded systems and a loss of confidence in renewable technology. The low volume of PV inverters produced restricts the manufacturing to small suppliers without sophisticated research and reliability programs or manufacturing methods. Thus, the present approach to PV inverter supply has low probability of meeting DOE reliability goals.

  9. Reliability-Driven Assessment of GaN HEMTs and Si IGBTs in 3L-ANPC PV Inverters

    DEFF Research Database (Denmark)

    Gurpinar, Emre; Yang, Yongheng; Iannuzzo, Francesco

    2016-01-01

    In this paper, thermal loading of the state-of-the-art GaN HEMTs and traditional Si IGBTs in 3L-ANPC PV inverters is presented considering real-field long-term mission profiles (i.e., ambient temperature and solar irradiance). A comparison of Si IGBT against GaN HEMT with three different possibil......In this paper, thermal loading of the state-of-the-art GaN HEMTs and traditional Si IGBTs in 3L-ANPC PV inverters is presented considering real-field long-term mission profiles (i.e., ambient temperature and solar irradiance). A comparison of Si IGBT against GaN HEMT with three different...... be achieved without compromise of operating efficiency with GaN HEMTs. Both simulations and experimental tests are provided to demonstrate the thermal loading analysis approach. More important, the proposed analysis and comparison approach can be used for lifetime and reliability analysis of wide...

  10. Development and implementation of a PV performance monitoring system based on inverter measurements

    DEFF Research Database (Denmark)

    Spataru, Sergiu; Gavriluta, Anamaria Florina; Maaløe, Lars

    2016-01-01

    Performance monitoring and fault detection systems have become necessary for decreasing operation and maintenance cost in large photovoltaic (PV) plants, as well for maximizing plan yield and lifetime. We expect a similar development for residential and commercial PV system applications, where...... the inverter’s own monitoring and communication capabilities. We also aim to lower the implementation cost, by using a simple, but accurate performance monitoring approach, and show the practical issues that can arise when implementing such a system....

  11. Control of Grid Interactive PV Inverters for High Penetration in Low Voltage Distribution Networks

    OpenAIRE

    Demirok, Erhan

    2012-01-01

    Regarding of high density deployment of PV installations in electricity grids, new technical challenges such as voltage rise, thermal loading of network components, voltage unbalance, harmonic interaction and fault current contributions are being added to tasks list of distribution system operators (DSOs) in order to maintain at least the same power quality as before PVs were not revealed. Potential problems caused by high amount of PV installations can be avoided with technical study of both...

  12. Research on comprehensive decision-making of PV power station connecting system

    Science.gov (United States)

    Zhou, Erxiong; Xin, Chaoshan; Ma, Botao; Cheng, Kai

    2018-04-01

    In allusion to the incomplete indexes system and not making decision on the subjectivity and objectivity of PV power station connecting system, based on the combination of improved Analytic Hierarchy Process (AHP), Criteria Importance Through Intercriteria Correlation (CRITIC) as well as grey correlation degree analysis (GCDA) is comprehensively proposed to select the appropriate system connecting scheme of PV power station. Firstly, indexes of PV power station connecting system are divided the recursion order hierarchy and calculated subjective weight by the improved AHP. Then, CRITIC is adopted to determine the objective weight of each index through the comparison intensity and conflict between indexes. The last the improved GCDA is applied to screen the optimal scheme, so as to, from the subjective and objective angle, select the connecting system. Comprehensive decision of Xinjiang PV power station is conducted and reasonable analysis results are attained. The research results might provide scientific basis for investment decision.

  13. Performance evaluation of a 2-mode PV grid connected system in Thailand -- Case study

    Energy Technology Data Exchange (ETDEWEB)

    Jivacate, C.; Mongconvorawan, S.; Sinratanapukdee, E.; Limsawatt, W. [Electricity Generating Authority of Thailand, Nontha Buri (Thailand)

    1994-12-31

    A PV grid connected system with small battery bank has been set up in a rural district, North Thailand in order to demonstrate a 2-mode operation concept. The objective is to gain experience on the PV grid connected concept without battery storage. However, due to the evening peak demand and a rather weak distribution grid which is typical in rural areas, small battery bank is still required to enable the maximum energy transfer to grid for the time being before moving fully to the no battery mode. The analyzed data seems to indicate possible performance improvement by re-arranging the number of PV modules and battery in the string.

  14. Grid-connected Photovoltaic Micro-inverter with New Hybrid Control LLC Resonant Converter

    DEFF Research Database (Denmark)

    Xingkui, Mao; Qisheng, Huang; Qingbo, Ke

    2016-01-01

    A high-efficiency photovoltaic (PV) micro-inverter consisting of two power stages i.e. a LLC resonant converter with a new hybrid control scheme and a dc-ac inverter is proposed, studied and designed in this paper. In the first power stage, the new hybrid control combining pulse-frequency modulat......A high-efficiency photovoltaic (PV) micro-inverter consisting of two power stages i.e. a LLC resonant converter with a new hybrid control scheme and a dc-ac inverter is proposed, studied and designed in this paper. In the first power stage, the new hybrid control combining pulse......-frequency modulation (PFM) and phase-shift pulse-width modulation (PS-PWM) is employed on a full-bridge LLC dc-dc converter, in order to achieve high efficiency when PV output voltage varies in a wide range. Moreover, a maximum power point tracking (MPPT) method based on power perturbation is implemented in the dc...

  15. High Quality Model Predictive Control for Single Phase Grid Connected Photovoltaic Inverters

    DEFF Research Database (Denmark)

    Zangeneh Bighash, Esmaeil; Sadeghzadeh, Seyed Mohammad; Ebrahimzadeh, Esmaeil

    2018-01-01

    Single phase grid-connected inverters with LCL filter are widely used to connect the photovoltaic systems to the utility grid. Among the presented control schemes, predictive control methods are faster and more accurate but are more complex to implement. Recently, the model-predictive control...... algorithm for single-phase inverter has been presented, where the algorithm implementation is straightforward. In the proposed approach, all switching states are tested in each switching period to achieve the control objectives. However, since the number of the switching states in single-phase inverter...... is low, the inverter output current has a high total harmonic distortions. In order to reduce the total harmonic distortions of the injected current, this paper presents a high-quality model-predictive control for one of the newest structure of the grid connected photovoltaic inverter, i.e., HERIC...

  16. A Novel Model Predictive Control for Single-Phase Grid-Connected Photovoltaic Inverters

    DEFF Research Database (Denmark)

    Zangeneh Bighash, Esmaeil; Sadeghzadeh, Seyed Mohammad; Ebrahimzadeh, Esmaeil

    2017-01-01

    Single-phase grid-connected inverters with LCL filter are widely used to connect photovoltaic systems to the utility grid. Among the existing control schemes, predictive control methods are faster and more accurate but also more complicated to implement. Recently, the Model Predictive Control (MPC......) algorithm for single-phase inverter has been presented, where the algorithm implementation is straightforward. In the MPC approach, all switching states are considered in each switching period to achieve the control objectives. However, since the number of switching states in single-phase inverters is small......, the inverter output current has a high Total Harmonic Distortions (THD). In order to reduce this, this paper presents an improved MPC for single-phase grid-connected inverters. In the proposed approach, the switching algorithm is changed and the number of the switching states is increased by means of virtual...

  17. Modeling of SVM Diode Clamping Three-Level Inverter Connected to Grid

    DEFF Research Database (Denmark)

    Guo, Yougui; Zeng, Ping; Zhu, Jieqiong

    2011-01-01

    PLECS is used to model the diode clamping three-level inverter connected to grid and good results are obtained. First the output voltage SVM is described for diode clamping three-level inverter with loads connected to Y. Then the output voltage SVM of diode clamping three-level inverter is simply...... analyzed with loads connected to △. But it will be further researched in the future. Third, PLECS is briefly introduced. Fourth, the modeling of diode clamping three-level inverter is briefly presented with PLECS. Finally, a series of simulations are carried out. The simulation results tell us PLECS...... is very powerful tool to real power circuits and it is very easy to simulate them. They have also verified that SVM control strategy is feasible to control the diode clamping three-level inverter....

  18. State-space-based harmonic stability analysis for paralleled grid-connected inverters

    DEFF Research Database (Denmark)

    Wang, Yanbo; Wang, Xiongfei; Chen, Zhe

    2016-01-01

    This paper addresses a state-space-based harmonic stability analysis of paralleled grid-connected inverters system. A small signal model of individual inverter is developed, where LCL filter, the equivalent delay of control system, and current controller are modeled. Then, the overall small signal...... model of paralleled grid-connected inverters is built. Finally, the state space-based stability analysis approach is developed to explain the harmonic resonance phenomenon. The eigenvalue traces associated with time delay and coupled grid impedance are obtained, which accounts for how the unstable...... inverter produces the harmonic resonance and leads to the instability of whole paralleled system. The proposed approach reveals the contributions of the grid impedance as well as the coupled effect on other grid-connected inverters under different grid conditions. Simulation and experimental results...

  19. Establishment of key grid-connected performance index system for integrated PV-ES system

    Science.gov (United States)

    Li, Q.; Yuan, X. D.; Qi, Q.; Liu, H. M.

    2016-08-01

    In order to further promote integrated optimization operation of distributed new energy/ energy storage/ active load, this paper studies the integrated photovoltaic-energy storage (PV-ES) system which is connected with the distribution network, and analyzes typical structure and configuration selection for integrated PV-ES generation system. By combining practical grid- connected characteristics requirements and technology standard specification of photovoltaic generation system, this paper takes full account of energy storage system, and then proposes several new grid-connected performance indexes such as paralleled current sharing characteristic, parallel response consistency, adjusting characteristic, virtual moment of inertia characteristic, on- grid/off-grid switch characteristic, and so on. A comprehensive and feasible grid-connected performance index system is then established to support grid-connected performance testing on integrated PV-ES system.

  20. Adaptive Droop Control Applied to Distributed Generation Inverters Connected to the Grid

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Teodorescu, Remus; Vásquez, Juan C.

    2008-01-01

    This paper proposes a novel control for voltage source inverters connected to the grid. The control scheme is based on the droop method, and it uses some estimated variables from the grid such as the voltage and the frequency, and the magnitude and angle of the grid impedance. Hence, the inverter...

  1. Co-design of the LCL Filter and Control for Grid-Connected Inverters

    DEFF Research Database (Denmark)

    Zhang, Yu; Xue, Mingyu; Li, Minying

    2014-01-01

    In most grid-connected inverters (GCI) with an LCL filter, since the design of both the LCL filter and the controller is done separately, considerable tuning efforts have to be exerted when compared to inverters using an L filter. Consequently, an integrated co-design of the filter and the contro...

  2. A new virtual-flux-vector based droop control strategy for parallel connected inverters in microgrids

    DEFF Research Database (Denmark)

    Hu, Jiefeng; Zhu, Jianguo; Qu, Yanqing

    2013-01-01

    Voltage and frequency droop method is commonly used in microgrids to achieve proper autonomous power sharing without rely on intercommunication systems. This paper proposes a new control strategy for parallel connected inverters in microgrid applications by drooping the flux instead of the invert...

  3. Prediction of Bond Wire Fatigue of IGBTs in a PV Inverter Under a Long-Term Operation

    DEFF Research Database (Denmark)

    Reigosa, Paula Diaz; Wang, Huai; Yang, Yongheng

    2016-01-01

    consumption of bond wires of IGBT modules in a Photovoltaic (PV) inverter. The variations in IGBT parameters (e.g., on-state collector-emitter voltage), lifetime models, and environmental and operational stresses are taken into account in the lifetime prediction. The distribution of the annual lifetime...... consumption is estimated based on a long-term annual stress profile of solar irradiance and ambient temperature. The proposed method enables a more realistic lifetime prediction with a specified confidence level compared to the state-of-the-art approaches. A study case of IGBT modules in a 10 kW three......Bond wire fatigue is one of the dominant failure mechanisms in IGBT modules under cyclic stresses. However, there are still major challenges ahead to achieve a realistic bond wire lifetime prediction in field operation. This paper proposes a Monte Carlo based analysis method to predict the lifetime...

  4. Operational characteristic analysis of PV generation system for grid connection by using a senseless MPPT control

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.-J.; Kim, K.-H.; Park, H.-Y.; Seo, H.-R.; Park, M.; Yu, I.-K. [Changwon National Univ., SarimDong (Korea, Republic of). Dept. of Electrical Engineering

    2007-07-01

    In photovoltaics, the sun's light energy is captured to create electricity. One of the key issues about a photovoltaic (PV) generation system is to keep the output power of photovoltaic cells maximized under any weather conditions. In a conventional maximum power point tracking (MPPT) control method, both voltage and current coming out from PV array require feedback. The system may fail to track the MPP of a PV array when unexpected weather conditions happen. This paper proposed a novel PV output senseless (POS) control method to solve the problem. The proposed POS MPPT control method only had one factor to consider, the load current. To verify this theory, a POS MPPT control was applied to a manufactured PV generation system, and the results of the the simulated and experimental data under real weather conditions were compared and analyzed. Several tables and diagrams were presented, including the circuit diagram of a manufactured PV generation system connected to grid as well as the the specifications of the PV array and PCS used for the experiment. Reasonable results were obtained in this study. In addition, the scheme was found to be very useful in maximizing power from PV array to load with feedback of only the load current. 8 refs., 3 tabs., 15 figs.

  5. Common voltage eliminating of SVM diode clamping three-level inverter connected to grid

    DEFF Research Database (Denmark)

    Guo, Yougui; Zeng, Ping; Zhu, Jieqiong

    2011-01-01

    A novel method of common voltage eliminating is put forward for SVM diode clamping three-level inverter connected to grid by calculation of common voltage of its various switching states. PLECS is used to model this three-level inverter connected to grid and good results are obtained. First...... analysis of common mode voltage for switching states of diode clamping 3-level inverter is given in detail. Second the common mode voltage eliminating control strategy of SVM is described for diode clamping three-level inverter. Third, PLECS is briefly introduced. Fourth, the modeling of diode clamping...... three-level inverter is presented with PLECS. Finally, a series of simulations are carried out. The simulation results tell us PLECS is a very powerful tool to real power circuits modeling. They have also verified that proposed common mode voltage eliminating control strategy of SVM is feasible...

  6. Analysis of the influences of grid-connected PV power system on distribution grids

    Directory of Open Access Journals (Sweden)

    Dumitru Popandron

    2013-12-01

    Full Text Available This paper presents the analysis of producing an electric power of 2.8 MW using a solar photovoltaic plant. The PV will be grid connected to the distribution network. The study is focused on the influences of connecting to the grid of a photovoltaic system, using modern software for analysis, modeling and simulation in power systems.

  7. Thermal Performance and Reliability Analysis of Single-Phase PV Inverters with Reactive Power Injection Outside Feed-In Operating Hours

    DEFF Research Database (Denmark)

    Anurag, Anup; Yang, Yongheng; Blaabjerg, Frede

    2015-01-01

    Reactive power support by photovoltaic (PV) systems is of increasingly interest, when compared to the conventional reactive power compensation devices. PV inverters can exchange reactive power with the utility grid in a decentralized manner even outside feed-in operation, especially at nights when...... there is no solar irradiance. However, reactive power injection causes additional power losses in the switching components leading to a temperature rise in the devices. Thus, this paper analyses the impact of reactive power injection by PV inverters outside feed-in operation on the thermal performance...... of their power switching components. A thermal analysis based on the mission profile (i.e., solar irradiance and ambient temperature) has been incorporated, so as to determine the additional temperature rise in the components induced by the operation outside feed-in hours. An analytical lifetime model has been...

  8. Control strategy based on SPWM switching patterns for grid connected photovoltaic inverter

    Science.gov (United States)

    Hassaine, L.; Mraoui, A.

    2017-02-01

    Generally, for lower installation of photovoltaic systems connected to the grid, pulse width modulation (PWM) is a widely used technique for controlling the voltage source inverters injects currents into the grid. The current injected must be sinusoidal with reduced harmonic distortion. In this paper, a digital implementation of a control strategy based on PWM switching patterns for an inverter for photovoltaic system connected to the grid is presented. This strategy synchronize a sinusoidal inverter output current with a grid voltage The digital implementation of the proposed PWM switching pattern when is compared with the conventional one exhibit the advantage: Simplicity, reduction of the memory requirements and power calculation for the control

  9. Grid-Voltage-Feedforward Active Damping for Grid-Connected Inverter with LCL Filter

    DEFF Research Database (Denmark)

    Lu, Minghui; Wang, Xiongfei; Blaabjerg, Frede

    2016-01-01

    For the grid-connected voltage source inverters, the feedforward scheme of grid voltage is commonly adopted to mitigate the current distortion caused by grid background voltages harmonics. This paper investigates the grid-voltage-feedforward active damping for grid connected inverter with LCL...... filter. It reveals that proportional feedforward control can not only fulfill the mitigation of grid disturbance, but also offer damping effects on the LCL filter resonance. Digital delays are intrinsic to digital controlled inverters; with these delays, the feedforward control can be equivalent...

  10. Efferent connections of the parvalbumin-positive (PV1) nucleus in the lateral hypothalamus of rodents.

    Science.gov (United States)

    Celio, Marco R; Babalian, Alexandre; Ha, Quan Hue; Eichenberger, Simone; Clément, Laurence; Marti, Christiane; Saper, Clifford B

    2013-10-01

    A solitary cluster of parvalbumin-positive neurons--the PV1 nucleus--has been observed in the lateral hypothalamus of rodents. In the present study, we mapped the efferent connections of the PV1 nucleus using nonspecific antero- and retrograde tracers in rats, and chemoselective, Cre-dependent viral constructs in parvalbumin-Cre mice. In both species, the PV1 nucleus was found to project mainly to the periaqueductal grey matter (PAG), predominantly ipsilaterally. Indirectly in rats and directly in mice, a discrete, longitudinally oriented cylindrical column of terminal fields (PV1-CTF) was identified ventrolateral to the aqueduct on the edge of the PAG. The PV1-CTF is particularly dense in the rostral portion, which is located in the supraoculomotor nucleus (Su3). It is spatially interrupted over a short stretch at the level of the trochlear nucleus and abuts caudally on a second parvalbumin-positive (PV2) nucleus. The rostral and the caudal portions of the PV1-CTF consist of axonal endings, which stem from neurons scattered throughout the PV1 nucleus. Topographically, the longitudinal orientation of the PV1-CTF accords with that of the likewise longitudinally oriented functional modules of the PAG, but overlaps none of them. Minor terminal fields were identified in a crescentic column of the lateral PAG, as well as in the Edinger-Westphal, the lateral habenular, and the laterodorsal tegmental nuclei. So far, no obvious functions have been attributed to this small, circumscribed column ventrolateral to the aqueduct, the prime target of the PV1 nucleus. © 2013 Wiley Periodicals, Inc.

  11. Analysis and Modeling of Circulating Current in Two Parallel-Connected Inverters

    DEFF Research Database (Denmark)

    Maheshwari, Ram Krishan; Gohil, Ghanshyamsinh Vijaysinh; Bede, Lorand

    2015-01-01

    Parallel-connected inverters are gaining attention for high power applications because of the limited power handling capability of the power modules. Moreover, the parallel-connected inverters may have low total harmonic distortion of the ac current if they are operated with the interleaved pulse...... this model, the circulating current between two parallel-connected inverters is analysed in this study. The peak and root mean square (rms) values of the normalised circulating current are calculated for different PWM methods, which makes this analysis a valuable tool to design a filter for the circulating......-width modulation (PWM). However, the interleaved PWM causes a circulating current between the inverters, which in turn causes additional losses. A model describing the dynamics of the circulating current is presented in this study which shows that the circulating current depends on the common-mode voltage. Using...

  12. Modified Transformerless Dual Buck Inverter with Improved Lifetime for PV Applications

    DEFF Research Database (Denmark)

    Khan, Ahmad; Blaabjerg, Frede

    2018-01-01

    (CM) operation. The analyses are verified on a 3 kW system. The results indicated that a capacitor of 30 μF is adequate to achieve a ripple free DC-Bus voltage for a 3 kW inverter. The size of this capacitor is 50 times smaller compared to the original capacitor required by the system. Also, unlike...... the non-neutral point clamped topologies that eliminate the ground leakage current (e.g. HERIC and H5), the proposed system can attain grid-codes under non-unity power-factor and low solar irradiance level conditions....

  13. Cost reduction in PV manufacturing. Impact on grid-connected and building-integrated markets

    International Nuclear Information System (INIS)

    Maycock, Paul D.

    1997-01-01

    In the past three years there have been several key events or changes that can lead to fully economic, massive deployment to the grid-connected and central PV markets. The factors discussed in this report include: (1) significant cost reduction in single crystal and polycrystal silicon so that modules profitably priced at $3.10-$3.30 per peak watt and installed grid-connected systems with installed cost of $5.50 per watt are being offered; (2) several new thin film plants - amorphous silicon, cadmium telluride, and copper indium diselenide are being built for 1996, 1997 production with greatly reduced costs; (3) government subsidized volume orders for PV in grid-connected houses (Japan, Germany, Switzerland, Italy, and the United States) provide volume (2000+ units per year) that lead to reduced costs; (4) environmental benefits for PV are being applied in Europe and Japan permitting 'early adopters' to enter the market; and (5) government and commercial acceptance of PV building integrated products, especially in Europe, are expanding PV markets. The combination of these forces lead to the prediction that an 'accelerated' market mode could start in the year 2000

  14. Feeder Voltage Regulation with High-Penetration PV Using Advanced Inverters and a Distribution Management System: A Duke Energy Case Study

    Energy Technology Data Exchange (ETDEWEB)

    Palmintier, Bryan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Giraldez, Julieta [National Renewable Energy Lab. (NREL), Golden, CO (United States); Gruchalla, Kenny [National Renewable Energy Lab. (NREL), Golden, CO (United States); Gotseff, Peter [National Renewable Energy Lab. (NREL), Golden, CO (United States); Nagarajan, Adarsh [National Renewable Energy Lab. (NREL), Golden, CO (United States); Harris, Tom [National Renewable Energy Lab. (NREL), Golden, CO (United States); Bugbee, Bruce [National Renewable Energy Lab. (NREL), Golden, CO (United States); Baggu, Murali [National Renewable Energy Lab. (NREL), Golden, CO (United States); Gantz, Jesse [GE Grid Solutions, Fairfield, CT (United States); Boardman, Ethan [GE Grid Solutions, Fairfield, CT (United States)

    2016-11-01

    Duke Energy, Alstom Grid, and the National Renewable Energy Laboratory teamed up to better understand the impacts of solar photovoltaics (PV) on distribution system operations. The core goal of the project is to compare the operational - specifically, voltage regulation - impacts of three classes of PV inverter operations: 1.) Active power only (Baseline); 2.) Local inverter control (e.g., PF...not equal...1, Q(V), etc.); and 3.) Integrated volt-VAR control (centralized through the distribution management system). These comparisons were made using multiple approaches, each of which represents an important research-and-development effort on its own: a) Quasi-steady-state time-series modeling for approximately 1 year of operations using the Alstom eTerra (DOTS) system as a simulation engine, augmented by Python scripting for scenario and time-series control and using external models for an advanced inverter; b) Power-hardware-in-the-loop (PHIL) testing of a 500-kVA-class advanced inverter and traditional voltage regulating equipment. This PHIL testing used cosimulation to link full-scale feeder simulation using DOTS in real time to hardware testing; c) Advanced visualization to provide improved insights into time-series results and other PV operational impacts; and d) Cost-benefit analysis to compare the financial and business-model impacts of each integration approach.

  15. System performance of a three-phase PV-grid-connected system installed in Thailand. Data monitored analysis

    International Nuclear Information System (INIS)

    Boonmee, Chaiyant; Watjanatepin, Napat; Plangklang, Boonyang

    2009-01-01

    PV-grid-connected systems are worldwide installed because it allows consumer to reduce energy consumption from the electricity grid and to feed the surplus energy back into the grid. The system needs no battery so therefore the system price is very cheap comparing to other PV systems. PV-grid-connected systems are used in buildings that already hooked up to the electrical grid. Finding efficiency of the PV-grid-connected system can be done by using a standard instrument which needs to disconnect the PV arrays from the grid before measurement. The measurement is also difficult and we lose energy during the measurement. This paper will present the system performance of a PV-grid-connected system installed in Thailand by using a monitoring system. The monitored data are installed by acquisition software into a computer. Analysis of monitored data will be done to find out the system performance without disconnecting the PV arrays from the system. The monitored data include solar radiation, PV voltage, PV current, and PV power which has been recorded from a 5 kWp system installed of amorphous silicon PV at Rajamangala University of Technology Suvarnabhumi, Nonthaburi, Thailand. The system performance of the system by using the data monitored is compared to the standard instrument measurement. The paper will give all details about system components, monitoring system, and monitored data. The result of data analysis will be fully given. (author)

  16. Integration of Hybrid PV/Wind Generation System Using Fuzzy MPPT in Grid Connected System for Remote Area

    Directory of Open Access Journals (Sweden)

    Soedibyo

    2016-01-01

    Full Text Available Photovoltaic and wind are renewable energy resources that widely used and grow rapidly in fulfilling electricity demand. Powers from both technologies depend on sunlight intensity and wind speed. For small scale power generation, DC voltage from both technologies is low and requires step-up converter to raise DC voltage ratio before converted into AC voltage. To optimize this system, step-up converter must have high ratio and efficiency to a distance of wide voltage input. This paper proposed an operation simulation and arrangement of DC-DC converter along with DC-AC from hybrid source PV-Wind which integrated to grid utilities without using storage device. High Gain Integrated Cascade Boost (HGICB is DC-DC converter that has quadratic voltage ratio and used in this research. Then DC link connected to Voltage Source Inverter (VSI which interconnected with utility grid and controlled by current control method. The total installed capacity of hybrid source is 4.4 kW. Wind turbine uses PMSG along with full bridge rectifier. To maximize and stabilize the generated power, MPPT fuzzy is used. Result from the simulation shows that converter capable to maintain maximum power whether from PV and wind turbine which canalized to utility grid in various irradiation condition, wind speed, and grid load alteration.

  17. Harmonic resonance assessment of multiple paralleled grid-connected inverters system

    DEFF Research Database (Denmark)

    Wang, Yanbo; Wang, Xiongfei; Blaabjerg, Frede

    2017-01-01

    This paper presents an eigenvalue-based impedance stability analytical method of multiple paralleled grid-connected inverter system. Different from the conventional impedance-based stability criterion, this work first built the state-space model of paralleled grid-connected inverters. On the basis...... of this, a bridge between the state-space-based modelling and impedance-based stability criterion is presented. The proposed method is able to perform stability assessment locally at the connection points of the component. Meanwhile, the eigenvalue-based sensitivity analysis is adopted to identify...

  18. Fuzzy comprehensive evaluation for grid-connected performance of integrated distributed PV-ES systems

    Science.gov (United States)

    Lv, Z. H.; Li, Q.; Huang, R. W.; Liu, H. M.; Liu, D.

    2016-08-01

    Based on the discussion about topology structure of integrated distributed photovoltaic (PV) power generation system and energy storage (ES) in single or mixed type, this paper focuses on analyzing grid-connected performance of integrated distributed photovoltaic and energy storage (PV-ES) systems, and proposes a comprehensive evaluation index system. Then a multi-level fuzzy comprehensive evaluation method based on grey correlation degree is proposed, and the calculations for weight matrix and fuzzy matrix are presented step by step. Finally, a distributed integrated PV-ES power generation system connected to a 380 V low voltage distribution network is taken as the example, and some suggestions are made based on the evaluation results.

  19. Droop-Controlled Inverters with Seamless Transition between Islanding and Grid-Connected Operations

    DEFF Research Database (Denmark)

    Hu, Shang-Hung; Kuo, Chun-Yi; Lee, Tzung-Lin

    2011-01-01

    This paper presents a seamless transition method for droop-controlled inverters to operate in both islanding and grid-connected modes. A local PLL and a virtual inductance are designed to ride through transient when the inverter switches between two modes with no synchronization. The proposed...... method can cooperatively work with well-developed droop controls so that the inverters are able to share load among them as well as subsist under transient events of the utility. Theoretical analysis and experimental results validate effectiveness of the proposed method....

  20. Possibilities and problems connected with the use of inverters

    Energy Technology Data Exchange (ETDEWEB)

    Brandolini, A

    1968-01-01

    The problem, which is not new, of dc electrical nets, feeding ac users, was investigated. An analytical treatment was carried out for studying a system formed by a dc line feeding a load through an inverter, with the result of keeping, for the expressions of the active and apparent power, forms which are similar to those of the simple sinusoidal case. It resulted that in the operation of dc ac mixed nets the problems involving the exchange of nonactive power are not more difficult than those which occur in common ac nets.

  1. Development of an Advanced Grid-Connected PV-ECS System Considering Solar Energy Estimation

    Science.gov (United States)

    Rahman, Md. Habibur; Yamashiro, Susumu; Nakamura, Koichi

    In this paper, the development and the performance of a viable distributed grid-connected power generation system of Photovoltaic-Energy Capacitor System (PV-ECS) considering solar energy estimation have been described. Instead of conventional battery Electric Double Layer Capacitors (EDLC) are used as storage device and Photovoltaic (PV) panel to generate power from solar energy. The system can generate power by PV, store energy when the demand of load is low and finally supply the stored energy to load during the period of peak demand. To realize the load leveling function properly the system will also buy power from grid line when load demand is high. Since, the power taken from grid line depends on the PV output power, a procedure has been suggested to estimate the PV output power by calculating solar radiation. In order to set the optimum value of the buy power, a simulation program has also been developed. Performance of the system has been studied for different load patterns in different weather conditions by using the estimated PV output power with the help of the simulation program.

  2. Quantitative Analysis Method of Output Loss due to Restriction for Grid-connected PV Systems

    Science.gov (United States)

    Ueda, Yuzuru; Oozeki, Takashi; Kurokawa, Kosuke; Itou, Takamitsu; Kitamura, Kiyoyuki; Miyamoto, Yusuke; Yokota, Masaharu; Sugihara, Hiroyuki

    Voltage of power distribution line will be increased due to reverse power flow from grid-connected PV systems. In the case of high density grid connection, amount of voltage increasing will be higher than the stand-alone grid connection system. To prevent the over voltage of power distribution line, PV system's output will be restricted if the voltage of power distribution line is close to the upper limit of the control range. Because of this interaction, amount of output loss will be larger in high density case. This research developed a quantitative analysis method for PV systems output and losses to clarify the behavior of grid connected PV systems. All the measured data are classified into the loss factors using 1 minute average of 1 second data instead of typical 1 hour average. Operation point on the I-V curve is estimated to quantify the loss due to the output restriction using module temperature, array output voltage, array output current and solar irradiance. As a result, loss due to output restriction is successfully quantified and behavior of output restriction is clarified.

  3. Topology and Control of Transformerless High Voltage Grid-connected PV System Based on Cascade Step-up Structure

    DEFF Research Database (Denmark)

    Yang, Zilong; Wang, Zhe; Zhang, Ying

    2017-01-01

    -up structure, instead of applying line-frequency step-up transformer, is proposed to connect PV directly to the 10 kV medium voltage grid. This series-connected step-up PV system integrates with multiple functions, including separated maximum power point tracking (MPPT), centralized energy storage, power...

  4. Simulation and Modeling of a Five -Level (NPC Inverter Fed by a Photovoltaic Generator and Integrated in a Hybrid Wind-PV Power System

    Directory of Open Access Journals (Sweden)

    M. Rezki,

    2017-08-01

    Full Text Available A distributed hybrid coordinated wind photovoltaic (PV power system was proposed in this paper. As oil and coal reserves are being depleted whilst at the same time the energy demand is growing, it is important to consider alternative energy generating techniques. Today, the five-level (NPC inverter represents a good alternative for several industrial applications. To take advantage of the five-level inverter topology and the benefits of renewable energy represented by a photovoltaic generator, a new scheme of these controllers is proposed in this work. This paper outlines the design of a hybrid power system consisting of a solar photovoltaic (PV and a wind power system. The system is modeled in Matlab Simulink and tested for various conditions. The model and results are discussed in this paper.

  5. Improved control strategy for the three-phase grid-connected inverter

    DEFF Research Database (Denmark)

    Yao, Zhilei; Xiao, Lan; Guerrero, Josep M.

    2015-01-01

    An improved control strategy for the three-phase grid-connected inverter with space vector pulse width modulation (SVPWM) is proposed. When the grid current contains harmonics, the d- and q-axis grid currents will be interacted, and then the waveform quality of the grid current will be poorer....... As the reference output voltage cannot directly reflect the change of the reference grid current, the dynamic response of the grid-connected inverter is slow. In order to solve the aforementioned problems, the d- and q-axis grid currents in the decoupled components of the grid current controller can be substituted...... by the d- and q-axis reference grid currents, respectively. The operating principles of the traditional and proposed control methods are illustrated. Experimental results for a 15-kVA three-phase grid-connected inverter with SVPWM verify the theoretical analysis. Compared with the traditional control...

  6. Frequency scanning-based stability analysis method for grid-connected inverter system

    DEFF Research Database (Denmark)

    Wang, Yanbo; Wang, Xiongfei; Blaabjerg, Frede

    2017-01-01

    This paper proposes a frequency scanning-based impedance analysis for stability assessment of grid-connected inverter system, which is able to perform stability assessment without using system mathematical models and inherit the superior feature of impedance-based stability criterion with conside......This paper proposes a frequency scanning-based impedance analysis for stability assessment of grid-connected inverter system, which is able to perform stability assessment without using system mathematical models and inherit the superior feature of impedance-based stability criterion...... with consideration of the inverter nonlinearities. Small current disturbance is injected into grid-connected inverter system in a particular frequency range, and the impedance is computed according to the harmonic-frequency response using Fourier analysis, and then the stability is predicted on the basis...... of the impedance stability criterion. The stability issues of grid-connected inverters with grid-current feedback and the converter-current feedback are addressed using the proposed method. The results obtained from simulation and experiments validate the effectiveness of the method. The frequency scanning...

  7. The implantation of a grid-connected PV system at CEPEL

    Energy Technology Data Exchange (ETDEWEB)

    Galdino, Marco Antonio, E-mail: marcoag@cepel.br

    2003-07-01

    This technical report presents the experience undertaken by CEPEL for implantation of a grid connected PV system at its headquarters, located in Rio de Janeiro, RJ, Brazil. This technology, although considered far from Brazilian reach, is expected to grow significantly in the near future. The paper describes briefly several aspects concerning the PV system and the DAS (data acquisition system) implemented in order to allow the continuous evaluation of its performance and operational conditions. The system was installed in December, 2002, and the data are still preliminary. (author)

  8. Online model-based fault detection for grid connected PV systems monitoring

    KAUST Repository

    Harrou, Fouzi

    2017-12-14

    This paper presents an efficient fault detection approach to monitor the direct current (DC) side of photovoltaic (PV) systems. The key contribution of this work is combining both single diode model (SDM) flexibility and the cumulative sum (CUSUM) chart efficiency to detect incipient faults. In fact, unknown electrical parameters of SDM are firstly identified using an efficient heuristic algorithm, named Artificial Bee Colony algorithm. Then, based on the identified parameters, a simulation model is built and validated using a co-simulation between Matlab/Simulink and PSIM. Next, the peak power (Pmpp) residuals of the entire PV array are generated based on both real measured and simulated Pmpp values. Residuals are used as the input for the CUSUM scheme to detect potential faults. We validate the effectiveness of this approach using practical data from an actual 20 MWp grid-connected PV system located in the province of Adrar, Algeria.

  9. Online model-based fault detection for grid connected PV systems monitoring

    KAUST Repository

    Harrou, Fouzi; Sun, Ying; Saidi, Ahmed

    2017-01-01

    This paper presents an efficient fault detection approach to monitor the direct current (DC) side of photovoltaic (PV) systems. The key contribution of this work is combining both single diode model (SDM) flexibility and the cumulative sum (CUSUM) chart efficiency to detect incipient faults. In fact, unknown electrical parameters of SDM are firstly identified using an efficient heuristic algorithm, named Artificial Bee Colony algorithm. Then, based on the identified parameters, a simulation model is built and validated using a co-simulation between Matlab/Simulink and PSIM. Next, the peak power (Pmpp) residuals of the entire PV array are generated based on both real measured and simulated Pmpp values. Residuals are used as the input for the CUSUM scheme to detect potential faults. We validate the effectiveness of this approach using practical data from an actual 20 MWp grid-connected PV system located in the province of Adrar, Algeria.

  10. A Low-Voltage Ride-Through Control Strategy for Three-Phase Grid-Connected PV Systems

    DEFF Research Database (Denmark)

    Afshari, Ehsan; Farhangi, Babak; Yang, Yongheng

    2017-01-01

    similar variations in the dc-link voltage of conventional two-stage PV inverters. In such systems with an electrolytic capacitor in the dc-link, the oscillations of the dc-link voltage with DGF can deteriorate the capacitor lifetime, and thus the entire system. The proposed Low-Voltage Ride-Through (LVRT...

  11. Monitoring and Fault Detection in Photovoltaic Systems Based On Inverter Measured String I-V Curves

    DEFF Research Database (Denmark)

    Spataru, Sergiu; Sera, Dezso; Kerekes, Tamas

    2015-01-01

    Most photovoltaic (PV) string inverters have the hardware capability to measure at least part of the current-voltage (I-V) characteristic curve of the PV strings connected at the input. However, this intrinsic capability of the inverters is not used, since I-V curve measurement and monitoring...... functions are not implemented in the inverter control software. In this paper, we aim to show how such a functionality can be useful for PV system monitoring purposes, to detect the presence and cause of power-loss in the PV strings, be it due to shading, degradation of the PV modules or balance......-of-system components through increased series resistance losses, or shunting of the PV modules. To achieve this, we propose and experimentally demonstrate three complementary PV system monitoring methods that make use of the I-V curve measurement capability of a commercial string inverter. The first method is suitable...

  12. A Modified Droop Control Method for Parallel-Connected Current Source Inverters

    DEFF Research Database (Denmark)

    Wei, Baoze; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez

    2016-01-01

    In this paper, a novel control method was proposed for current source inverters under the grid-connected working mode. The control scheme is based on a modified droop control method, with an additional current reference signal that will be generated instead of the voltage reference. Hence......, there is only a current control loop with droop control in the whole control scheme without voltage control loop. So it is very suitable for grid-connected current source inverter which will simplify the design of the control scheme and combine the advantage of droop control. The parallel configuration...... is widely used to acquire high power demand, but the circulating current problem is a key issue that should be considered. In this paper, a simulation based on parallel current source inverters using the proposed control scheme is provided. Simulation results showed that a good circulating current...

  13. Analysis of grid connected solar PV system in the Southeastern Part of Bangladesh

    International Nuclear Information System (INIS)

    Ariful Islam; Fatema Akther Shima; Akhera Khanam

    2013-01-01

    Bangladesh is a potential site of implementing renewable energy system to reduce the severe power crisis throughout the year. According to this, Chittagong is the southeastern part of Bangladesh is also a potential site for implementing renewable energy system such as grid-connected photovoltaic (PV) system. Financial viability and green-house gas emission reduction of solar PV as an electricity generation source are assessed for 500 kW grid connected solar PV system at University of Chittagong, Chittagong. Homer simulation soft-ware and monthly average solar radiation data from NASA is used for this task. In the proposed system monthly electricity generation varies between 82.65 MW h and 60.3 MW h throughout the year with a mean value of 68.25 MW h depending on the monthly highest and lowest solar radiation data. It is found that per unit electricity production cost is US$ 0.20 based on project lifetime 25 years. The IRR, equity payback and benefit-cost ratio shows favorable condition for development of the proposed solar PV system in this site. A minimum 664 tones of green-house gas emissions can be reduced annually utilizing the proposed system. (authors)

  14. Adaptive Synchronization of Grid-Connected Threephase Inverters by Using Virtual Oscillator Control

    DEFF Research Database (Denmark)

    Li, Mingshen; Gui, Yonghao; Guerrero, Josep M.

    2018-01-01

    This paper presents an adaptive synchronization for current-controlled grid-connected inverter based on a time domain virtual oscillator controller (VOC). Inspired by the phenomenon of dynamics of adaptive oscillator under the perturbation effect. Firstly, the fast learning rule of the oscillator...

  15. Single-Phase 3L PR Controlled qZS Inverter Connected to the Distorted Grid

    DEFF Research Database (Denmark)

    Makovenko, Elena; Husev, Oleksandr; Roncero-Clemente, Carlos

    2016-01-01

    This paper presents a single-phase three-level NPC qZS inverter connected to a distorted grid using PID and PR regulators. A case study system along with the control strategy are described. Tuning approaches for PID and PR regulators are addressed and validated by means of simulation results...

  16. Progress in markets for grid-connected PV systems in the built environment

    International Nuclear Information System (INIS)

    Haas, R.

    2004-01-01

    In the last decade of the twentieth century a wide variety of promotion strategies increased the market penetration of small grid-connected PV systems world-wide. The objective of this paper is to assess the impact of these promotion strategies on the market for and on the economic performance of small grid-connected PV systems. The most important conclusions of this analysis are: Pure cost-effectiveness is not crucial for private customers. Affordability is rather what counts. Non-monetary issues play an important role for a substantial increase in market deployment. Comprehensive accompanied information and education activities are also important along with financial incentives. There are still considerable barriers in the market: on the one hand transparent and competitive markets exist in only a few countries; on the other hand non-monetary transaction costs still represent a major barrier. Progress with respect to cost reduction has been achieved, but mainly for non-module components. (author)

  17. Performance of a grid connected PV system used as active filter

    International Nuclear Information System (INIS)

    Calleja, Hugo; Jimenez, Humberto

    2004-01-01

    In this paper, the performance of a grid connected photovoltaic (PV) system used as an active filter is presented. Its main feature is the capability to compensate the reactive and harmonic currents drawn by nonlinear loads while simultaneously injecting into the grid the maximum power available from the cells. The system can also operate as a stand alone active filter. The system was connected to a 1 kW PV array and tested with the loads typically found in households: small motors, personal computers and electronic ballasts. The results show that the system can correct the power factor to values close to unity for all the cases tested, thereby improving the efficiency of the electric energy supply

  18. Reduced-Order Structure-Preserving Model for Parallel-Connected Three-Phase Grid-Tied Inverters

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Brian B [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Purba, Victor [University of Minnesota; Jafarpour, Saber [University of California Santa-Barbara; Bullo, Francesco [University of California Santa-Barbara; Dhople, Sairaj V. [University of Minnesota

    2017-08-21

    Next-generation power networks will contain large numbers of grid-connected inverters satisfying a significant fraction of system load. Since each inverter model has a relatively large number of dynamic states, it is impractical to analyze complex system models where the full dynamics of each inverter are retained. To address this challenge, we derive a reduced-order structure-preserving model for parallel-connected grid-tied three-phase inverters. Here, each inverter in the system is assumed to have a full-bridge topology, LCL filter at the point of common coupling, and the control architecture for each inverter includes a current controller, a power controller, and a phase-locked loop for grid synchronization. We outline a structure-preserving reduced-order inverter model with lumped parameters for the setting where the parallel inverters are each designed such that the filter components and controller gains scale linearly with the power rating. By structure preserving, we mean that the reduced-order three-phase inverter model is also composed of an LCL filter, a power controller, current controller, and PLL. We show that the system of parallel inverters can be modeled exactly as one aggregated inverter unit and this equivalent model has the same number of dynamical states as any individual inverter in the system. Numerical simulations validate the reduced-order model.

  19. Reduced-Order Structure-Preserving Model for Parallel-Connected Three-Phase Grid-Tied Inverters: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Brian B [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Purba, Victor [University of Minnesota; Jafarpour, Saber [University of California, Santa Barbara; Bullo, Francesco [University of California, Santa Barbara; Dhople, Sairaj [University of Minnesota

    2017-08-31

    Given that next-generation infrastructures will contain large numbers of grid-connected inverters and these interfaces will be satisfying a growing fraction of system load, it is imperative to analyze the impacts of power electronics on such systems. However, since each inverter model has a relatively large number of dynamic states, it would be impractical to execute complex system models where the full dynamics of each inverter are retained. To address this challenge, we derive a reduced-order structure-preserving model for parallel-connected grid-tied three-phase inverters. Here, each inverter in the system is assumed to have a full-bridge topology, LCL filter at the point of common coupling, and the control architecture for each inverter includes a current controller, a power controller, and a phase-locked loop for grid synchronization. We outline a structure-preserving reduced-order inverter model for the setting where the parallel inverters are each designed such that the filter components and controller gains scale linearly with the power rating. By structure preserving, we mean that the reduced-order three-phase inverter model is also composed of an LCL filter, a power controller, current controller, and PLL. That is, we show that the system of parallel inverters can be modeled exactly as one aggregated inverter unit and this equivalent model has the same number of dynamical states as an individual inverter in the paralleled system. Numerical simulations validate the reduced-order models.

  20. Application of Fuzzy Control in a Photovoltaic Grid-Connected Inverter

    Directory of Open Access Journals (Sweden)

    Zhaohong Zheng

    2018-01-01

    Full Text Available To realize the maximum power output of a grid-connected inverter, the MPPT (maximum power point tracking control method is needed. The perturbation and observation (P&O method can cause the inverter operating point to oscillate near the maximum power. In this paper, the fuzzy control P&O method is proposed, and the fuzzy control algorithm is applied to the disturbance observation method. The simulation results of the P&O method with fuzzy control and the traditional P&O method prove that not only can the new method reduce the power loss caused by inverter oscillation during maximum power point tracking, but also it has the advantage of speed. Inductive loads in the post-grid-connected stage cause grid-connected current distortion. A fuzzy control algorithm is added to the traditional deadbeat grid-connected control method to improve the quality of the system’s grid-connected operation. The fuzzy deadbeat control method is verified by experiments, and the harmonic current of the grid-connected current is less than 3%.

  1. Marketing residential grid-connected PV systems using a balanced scorecard as a marketing tool

    International Nuclear Information System (INIS)

    Bach, N.; Calais, P.; Calais, M.

    2001-01-01

    A strategic analysis of the electricity market in Western Australia yields a market potential for renewable energy in Western Australia. However, from a purely financial viewpoint the installation of grid-connected pv-systems still is not economically viable. In this paper a balanced scorecard (BSC) is developed to capture and visualize other than financial benefits. Therefore, the BSC can be used as a marketing tool to communicate the benefits of a privately owned GCPV system to potential customers. (author)

  2. System modelling and energy management for grid connected PV systems associated with storage

    OpenAIRE

    Riffonneau , Yann; DELAILLE , Arnaud; Barruel , Franck; Bacha , Seddik

    2008-01-01

    International audience; This paper presents the modelling and energy management of a grid connected PV system associatedwith storage. Within the economic, energetic and environmental context, objective of the system is to ensure loadssupply at the least cost by optimising the use of solar power. Therefore, due to the complicated operating patterns, anenergy management system which decides on energy flow for any moment is necessary. First, we present the systemstudied. Based on an AC bus typol...

  3. Regulatory potential for increasing small scale grid connected photovoltaic (PV) deployment in Australia

    International Nuclear Information System (INIS)

    Sivaraman, Deepak; Horne, Ralph E.

    2011-01-01

    The last decade has seen significant innovation and change in regulatory incentives to support photovoltaic deployment globally. With high fossil fuel dependency and abundant solar resource availability in Australia, grid connected photovoltaics are a viable low carbon technology option in existing electricity grids. Drawing on international examples, the potential to increase grid PV deployment through government response and regulation is explored. For each renewable energy certificate (REC) earned by small scale photovoltaics until 2012, the market provides four additional certificates under the current banded renewable targets. Our analysis indicates that REC eligibility is not accurately estimated currently, and an energy model is developed to calculate the variance. The energy model estimates as much as 26% additional REC's to be obtained by a 3 kWp PV system, when compared to the currently used regulatory method. Moreover, the provision of REC's increases benefits to PV technologies, in the process distorting CO 2 abatement (0.21 tonne/REC) by 68%, when PV displaces peaking natural gas plants. Consideration of the secondary effects of a banded structure on emissions trading market is important in the context of designing a range of initiatives intended to support a transition to a low carbon electricity sector. - Research Highlights: →Grid connected photovoltaics hedge spikes in peak demand summer electricity prices. →Nationwide feed in tariff and new building regulations needed to increase PV deployment. →Australia has transitioned from a solar rebate to a banded solar credit structure. →The currently used regulatory deeming method underestimates REC eligibility by 27%. →The banded structure can potentially distort CO 2 abatement by as much as 68%.

  4. Flexible Control Strategy for Grid-Connected Inverter under Unbalanced Grid Faults without PLL

    DEFF Research Database (Denmark)

    Guo, Xiaoqiang; Liu, W.; Zhang, X.

    2015-01-01

    Power oscillation and current quality are the important performance targets for the grid-connected inverter under unbalanced grid faults. Firstly, the inherent reason for the current harmonic and power oscillation of the inverter is discussed with a quantitative analysis. Secondly, a new control...... strategy is proposed to achieve the coordinate control of power and current quality without the need for a phase-locked loop or voltage/current positive/negative sequence extraction calculation. Finally, the experimental tests are conducted under unbalanced grid faults, and the results verify...

  5. Small-Signal Modeling and Analysis of Grid-Connected Inverter with Power Differential Droop Control

    Directory of Open Access Journals (Sweden)

    Xin Chen

    2016-01-01

    Full Text Available The conventional voltage and frequency droop control strategy in grid-connected inverter suffers a major setback in the presence of disturbance by producing oscillations. Adding a power differential term in droop controller is an effective way to address such drawback. In this paper, grid-connected inverter’s small-signal models of the conventional droop control and the power differential droop control are established. The eigenvalues of the models are then determined by system matrix. The eigenvalues analysis is presented which helps in identifying the relationship between the system stability and controller parameters. It is concluded that the damping ratio of dominant low-frequency eigenvalues increased and the oscillation caused by the disturbance is suppressed when a power differential term is added to the droop control method. The MATLAB/Simulink models of grid-connected inverter with both control strategies are also established to validate the results of small-signal analysis.

  6. Experimental Implementation of a Low-Cost Single Phase Five-Level Inverter for Autonomous PV System Applications Without Batteries

    OpenAIRE

    Nouaiti, Ayoub; Saad, Abdallah; Mesbahi, Abdelouahed; Khafallah, Mohamed

    2018-01-01

    This paper presents the design and the implementation of a low-cost single phase five-level inverter for photovoltaic applications. The proposed multilevel inverter is composed of a simple boost converter, a switched-capacitor converter, and an H-bridge converter. An efficient control method which associates a closed-loop regulation method with a simple maximum power point tracking (MPPT) method is applied in order to allow the proposed multilevel inverter to transfer power energy from solar ...

  7. Adaptive super-twisting sliding mode control for a three-phase single-stage grid-connected differential boost inverter based photovoltaic system.

    Science.gov (United States)

    Pati, Akshaya K; Sahoo, N C

    2017-07-01

    This paper presents an adaptive super-twisting sliding mode control (STC) along with double-loop control for voltage tracking performance of three-phase differential boost inverter and DC-link capacitor voltage regulation in grid-connected PV system. The effectiveness of the proposed control strategies are demonstrated under realistic scenarios such as variations in solar insolation, load power demand, grid voltage, and transition from grid-connected to standalone mode etc. Additional supplementary power quality control functions such as harmonic compensation, and reactive power management are also investigated with the proposed control strategy. The results are compared with conventional proportional-integral controller, and PWM sliding mode controller. The system performance is evaluated in simulation and in real-time. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  8. Challenges to Grid Synchronization of Single-Phase Grid-Connected Inverters in Zero-Voltage Ride-Through Operation

    DEFF Research Database (Denmark)

    Zhang, Zhen; Yang, Yongheng; Blaabjerg, Frede

    2016-01-01

    With the fast development in Photovoltaic (PV) technology, the relevant grid-connection requirements/standards are continuously being updated, and more challenges have been imposed on both single-phase and three-phase grid-connected PV systems. For instance, PV systems are currently required...... to remain connected under grid voltage sags (even zero voltage condition). In this case, much attention should be paid to the grid synchronization in such a way to properly ride-through grid faults. Thus, in this paper, the most commonly-used and recently-developed Phase Locked Loop (PLL) synchronization...... methods have been evaluated for single-phase grid-connected PV systems in the case of Zero-Voltage Ride-Through (ZVRT) operation. The performances of the prior-art PLL methods in response to zero voltage faults in terms of detection precision and dynamic response are assessed in this paper. Simulation...

  9. Modeling and design of a multivariable control system for multi-paralleled grid-connected inverters with LCL filter

    DEFF Research Database (Denmark)

    Akhavan, Ali; Mohammadi, Hamid Reza; Guerrero, Josep M.

    2018-01-01

    The quality of injected current in multi-paralleled grid-connected inverters is a matter of concern. The current controlled grid-connected inverters with LCL filter are widely used in the distributed generation (DG) systems due to their fast dynamic response and better power features. However...... with resonances in the system, damping methods such as passive or active damping is necessary. Secondly and perhaps more importantly, paralleled grid-connected inverters in a microgrid are coupled due to grid impedance. Generally, the coupling effect is not taken into account when designing the control systems...

  10. Brushless DC motor drives supplied by PV power system based on Z-source inverter and FL-IC MPPT controller

    International Nuclear Information System (INIS)

    Mozaffari Niapour, S.A.KH.; Danyali, S.; Sharifian, M.B.B.; Feyzi, M.R.

    2011-01-01

    Highlights: → Employing the BLDC motor in water pumping systems. → Utilizing the ZSI as a single-stage power converter in the PV water pumping systems based on BLDC motor. → Improvement of the conventional IC MPPT method with the fuzzy logic control scheme to save more energy from the PV array. → Taking the advantages of the DTC drive of the BLDC motor. → Optimizing the water pumping system speed response characteristic by PSO. - Abstract: This paper discusses operation performance of a water pumping system consist of a brushless dc (BLDC) motor coupled a centrifugal pump and accompanying a Z-source inverter (ZSI) fed by a photovoltaic (PV) array, to be improved. Despite conventional double-stage power converters, this paper proposes utilizing a single-stage ZSI to extract the maximum power of the PV array and supply the BLDC motor simultaneously. Utilizing the ZSI provides some inherent advantages such as high efficiency and low cost, which is very promising for PV systems due to its novel voltage buck/boost capability. In addition, in order to precisely perform the maximum power point tracking (MPPT) of the PV array the fuzzy logic-incremental conductance (FL-IC) MPPT scheme is proposed. The proposed FL-IC MPPT scheme provides enough modification to the conventional IC method to enjoy an appropriate variable step size MPPT control signal for the ZSI. Moreover, direct torque control (DTC) is found more effective in comparison with hysteresis current control with current shaping to drive the BLDC motor, because it benefits from faster torque response, reduced torque ripple, less sensitivity to parameters variations, and simple implementation. In the mean time, due to the frequently variations of the PV power generation; delivered mechanical power to the centrifugal pump is variable. Thus, the BLDC motor should be driven with variable reference speed. In order to improve the speed transient response of the BLDC motor and enhance the energy saving aspect of

  11. Optimising the economic viability of grid-connected photovoltaic systems

    International Nuclear Information System (INIS)

    Mondol, Jayanta Deb; Yohanis, Yigzaw G; Norton, Brian

    2009-01-01

    The impact of photovoltaic (PV) array size, orientation, inclination, load profile, electricity buying price, feed-in tariffs, PV/inverter sizing ratio ('sizing ratio') and PV/inverter cost ratio ('cost ratio') on the economic viability of a grid-connected PV system was investigated using a validated TRNSYS simulation model. The results showed that the fractional load met directly by a PV system depends on matching between PV supply and building load profile, sizing ratio and PV inclination. The profitability of a grid-connected PV system increases if the PV system is sized to reduce excess PV electrical energy fed to the grid when the feed-in tariff is lower than electricity buying price. The effect of feed-in tariffs on PV saving for selected European countries has been shown. The cost of the PV electricity depends on sizing ratio, PV and inverter lifetimes, cost ratio, PV inclination and financial parameters. The effect of cost ratio on the optimum PV/inverter sizing ratio is less significant when the cost ratio lies within 7-11. The minimum PV electricity cost at low and high insolation conditions were obtained for sizing ratios of 1.6 and 1.2, respectively. The lowest PV electricity cost was found for surface slopes within 30-40 for the selected European locations. The PV electricity cost for cost ratio of 5 and 13 varied from 0.44-0.85 EURkWh -1 to 0.38-0.76 EURkWh -1 , respectively within high to low insolation conditions when the PV module unit cost, market discount rate, PV size, PV lifetime and inverter lifetime were assumed to be 6.5 EURW p -1 , 3%, 13 kW p , 20 years and 10 years, respectively. (author)

  12. Power Enhancement of Partial Shaded PV Array by Optimizing the Electrical Connection of Module

    Directory of Open Access Journals (Sweden)

    Wang Mengyao

    2015-01-01

    Full Text Available The maximum output power (Pmax generated from photovoltaic (PV array will be apparently reduced if the array is partially shaded. In order to enhance Pmax generated from partial shaded PV array, several interconnection schemes of array are proposed. Among these schemes, the totally cross tied (TCT scheme and the recently proposed static scheme are widely discussed. It was reported that Pmax produced with static scheme is equal to the TCT scheme even under worst conditions. However, in these simulations the illumination of every single module is assumed to be uniform, but in urban environments the illumination of modules on the edge of shadow is more likely to be non-uniform. In this paper, first, a comprehensive circuit-level simulation, which is implemented in PSpice, has been done to investigate performance of PV array with both TCT scheme and static scheme under different partial shading conditions. And the results show that Pmax generated from static scheme is higher than that form TCT scheme if the illumination of every single module is uniform, however if some modules are partially shaded, the Pmax with static scheme is more likely less than that with TCT scheme. Then, the electrical connection of a module is improved for the purpose of enhancing Pmax under partial shading conditions in which some modules in the array are partially shaded. And the simulation results show that Pmax is apparently increased by employing the improved modules.

  13. Design and Control of an Inverter for Photovoltaic Applications

    DEFF Research Database (Denmark)

    Kjær, Søren Bækhøj

    The energy demand in the world is steadily increasing and new types of energy sources must be found in order to cover the future demands, since the conventional sources are about to be emptied. One type of renewable energy source is the photovoltaic (PV) cell, which converts sunlight to electrical...... current, without any form for mechanical or thermal interlink. PV cells are usually connected together to make PV modules, consisting of 72 PV cells, which generates a DC voltage between 23 Volt to 45 Volt and a typical maximum power of 160 Watt, depending on temperature and solar irradiation....... The electrical infrastructure around the world is based on AC voltage, with a few exceptions, with a voltage of 120 Volt or 230 Volt in the distribution grid. PV modules can therefore not be connected directly to the grid, but must be connected through an inverter. The two main tasks for the inverter are to load...

  14. Dynamic Evaluation of LCL-type Grid-Connected Inverters with Different Current Feedback Control Schemes

    DEFF Research Database (Denmark)

    Han, Yang; Li, Zipeng; Guerrero, Josep M.

    2015-01-01

    typical current feedback control schemes in LCL grid-connected system are analyzed and compared systematically. Analysis in s-domain take the effect of the digital computation and modulation delay into account. The stability analysis is presented by root locus in the discrete domain, the optimal values......Proportional-resonant (PR) compensator and LCL filter becomes a better choice in grid-connected inverter system with high performance and low costs. However, the resonance phenomenon caused by LCL filter affect the system stability significantly. In this paper, the stability problem of three...

  15. RMS Current of a Photovoltaic Generator in Grid-Connected PV Systems: Definition and Application

    Directory of Open Access Journals (Sweden)

    P. J. Pérez

    2008-01-01

    Full Text Available This paper includes a definition of a new and original concept in the photovoltaic field, RMS current of a photovoltaic generator for grid-connected systems. The RMS current is very useful for calculating energy losses in cables used in a PV generator. As well, a current factor has been defined in order to simplify RMS current calculation. This factor provides an immediate (quick and easy calculation method for the RMS current that does not depend on the case particular conditions (orientation, location, etc.. RMS current and current factor values have been calculated for different locations and modules.

  16. Reliability-Oriented Design and Analysis of Input Capacitors in Single-Phase Transformer-less Photovoltaic Inverters

    DEFF Research Database (Denmark)

    Wang, Huai; Yang, Yongheng; Blaabjerg, Frede

    2013-01-01

    While 99% efficiency has been reported, the target of 20 years of service time imposes new challenge to cost-effective solutions for grid-connected photovoltaic (PV) inverters. Aluminum electrolytic capacitors are the weak-link in terms of reliability and lifetime in single-phase PV systems....... A reliability-oriented design guideline is proposed in this paper for the input capacitors in single-phase transformer-less PV inverters. The guideline ensures that the service time requirement is to be accomplished under different power levels and ambient temperature profiles. The theoretical analysis has been...... demonstrated by a 1 kW single-phase PV inverter....

  17. Finishing report for the 'SolcelleInverter' project

    Energy Technology Data Exchange (ETDEWEB)

    Boekhoej Kjaer, S.

    2005-03-01

    The main objective for this research project was to develop an inverter for the AC module, where one PV module is equipped with its own dedicated inverter, and connected to the grid. A topology, among many different candidates, has been selected, based on analysis's. The inverter has been optimized in respect to cost, reliability, and efficiency, and a prototype has been build. (au)

  18. A Novel Neutral Point Clamped Full-Bridge Topology for Transformerless Photovoltaic Grid-Connected Inverters

    Directory of Open Access Journals (Sweden)

    M. Pakdel

    2017-04-01

    Full Text Available This paper presents a novel neutral point clamped full-bridge topology for transformerless photovoltaic grid-tied inverters. Transformerless grid-connected inverters have been used widely in recent years since they offer higher efficiency and lower costs. Ground leakage current suppression is the main issue which should be considered carefully in transformerless photovoltaic grid-connected inverters. Among different methods used to decline ground leakage current, neutral point clamped (NPC topologies are considered more useful and effective. In NPC topologies, the short-circuited output voltage at the freewheeling period is clamped to the middle of the DC bus voltage. Therefore, the common-mode voltage (CM will be constant at the whole switching period. Various NPC topologies such as H6 [1], HB-ZVR [2], oH5 [3], and PN-NPC [4] have been proposed. In this paper, a novel NPC topology is proposed which has lower power losses and higher efficiency over previous topologies. Furthermore, the proposed NPC topology exhibits a similar ground leakage current with the PN-NPC topology. The proposed NPC topology is analyzed theoretically using simulation studies and an experimental prototype is provided to verify theoretical analysis and simulation studies.

  19. Low voltage ride-through capability control for single-stage inverter-based grid-connected photovoltaic power plant

    DEFF Research Database (Denmark)

    Al-Shetwi, Ali Q.; Sujod, Muhamad Zahim; Blaabjerg, Frede

    2018-01-01

    to enhance the LVRT capability based on the Malaysian standards and modern grid codes connection requirements. The proposed control overcomes the problems of dc-link over-voltage and ac over-current that may cause disconnection or damage to the inverter. For this purpose, dc-chopper brake controller...... to improve the capability of ride-through fault safely and keep the inverter connected, but also to provide grid support through active and reactive power control at different type of faults....

  20. Research on LLCL Filtering Grid - Connected inverter under the Control of PFI

    Science.gov (United States)

    Li, Ren-qing; Zong, Ke-yong; Wang, Yan-ping; Li, Yang; Zhang, Jing

    2018-03-01

    This passage puts forward a kind of LLCL inverter which is based on the proportional feedback integral(PFI) control so as so satisfy the request of the grid-current outputed by the renewable energy generation system. The passage builds the topological graph of grid-connected inverter and makes an analysis of principle of linear superposition aims to reveal the essence of the problem of steady-state error that exists in proportional integral control. We use LLCL filter and the method of passive damping to solve the problem of resonant peak. We make simulation of the grid system with the software named MATLAB/Simulink. The result shows that the grid current enters steady state quickly and in the same time, which has the identical phase and frequency of grid-voltage. The harmonic content in grid current satisfies the request of grid standard.

  1. Experimental Implementation of a Low-Cost Single Phase Five-Level Inverter for Autonomous PV System Applications Without Batteries

    Directory of Open Access Journals (Sweden)

    A. Nouaiti

    2018-02-01

    Full Text Available This paper presents the design and the implementation of a low-cost single phase five-level inverter for photovoltaic applications. The proposed multilevel inverter is composed of a simple boost converter, a switched-capacitor converter, and an H-bridge converter. An efficient control method which associates a closed-loop regulation method with a simple maximum power point tracking (MPPT method is applied in order to allow the proposed multilevel inverter to transfer power energy from solar panels to autonomous load with no storage batteries. An experimental prototype of this inverter is fabricated at the laboratory and tested with a digital control system. Obtained results confirm the simplicity and the performance of the proposed photovoltaic system.

  2. On-line grid impedance estimation based on harmonic injection for grid-connected PV inverter

    DEFF Research Database (Denmark)

    Ciobotaru, Mihai; Teodorescu, Remus; Blaabjerg, Frede

    2007-01-01

    two different signal processing algorithms. The DFT technique is used for the single harmonic injection and the statistic technique is used for the double harmonic injection. The grid impedance estimation is used for compliance with the anti-islanding requirements of the German standard (VDE0126...

  3. Feasibility Study of Grid Connected PV-Biomass Integrated Energy System in Egypt

    Science.gov (United States)

    Barakat, Shimaa; Samy, M. M.; Eteiba, Magdy B.; Wahba, Wael Ismael

    2016-10-01

    The aim of this paper is to present a feasibility study of a grid connected photovoltaic (PV) and biomass Integrated renewable energy (IRE) system providing electricity to rural areas in the Beni Suef governorate, Egypt. The system load of the village is analyzed through the environmental and economic aspects. The model has been designed to provide an optimal system configuration based on daily data for energy availability and demands. A case study area, Monshaet Taher village (29° 1' 17.0718"N, 30° 52' 17.04"E) is identified for economic feasibility in this paper. HOMER optimization model plan imputed from total daily load demand, 2,340 kWh/day for current energy consuming of 223 households with Annual Average Insolation Incident on a Horizontal Surface of 5.79 (kWh/m2/day) and average biomass supplying 25 tons / day. It is found that a grid connected PV-biomass IRE system is an effective way of emissions reduction and it does not increase the investment of the energy system.

  4. All SiC Grid-Connected PV Supply with HF Link MPPT Converter: System Design Methodology and Development of a 20 kHz, 25 kVA Prototype

    Directory of Open Access Journals (Sweden)

    Serkan Öztürk

    2018-05-01

    Full Text Available Design methodology and implementation of an all SiC power semiconductor-based, grid-connected multi-string photovoltaic (PV supply with an isolated high frequency (HF link maximum power point tracker (MPPT have been described. This system configuration makes possible the use of a simple and reliable two-level voltage source inverter (VSI topology for grid connection, owing to the galvanic isolation provided by the HF transformer. This topology provides a viable alternative to the commonly used non-isolated PV supplies equipped with Si-based boost MPPT converters cascaded with relatively more complex inverter topologies, at competitive efficiency figures and a higher power density. A 20 kHz, 25 kVA prototype system was designed based on the dynamic model of the multi-string PV panels obtained from field tests. Design parameters such as input DC link capacitance, switching frequencies of MPPT converter and voltage source inverter, size and performance of HF transformer with nanocrystalline core, DC link voltage, and LCL filter of the VSI were optimized in view of the site dependent parameters such as the variation ranges of solar insolation, module surface temperature, and grid voltage. A modified synchronous reference frame control was implemented in the VSI by applying the grid voltage feedforward to the reference voltages in abc axes directly, so that zero-sequence components of grid voltages are taken into account in the case of an unbalanced grid. The system was implemented and the proposed design methodology verified satisfactorily in the field on a roof-mounted 23.7 kW multi-string PV system.

  5. Stability identification for grid-connected inverters with LCL filters considering grid-voltage feedforward regulator

    DEFF Research Database (Denmark)

    Lu, Minghui; Blaabjerg, Frede

    2017-01-01

    This paper identifies stable resonance frequency range for grid-connected inverter with Grid-Voltage Feedforward Regulator (GVFR). Beginning with the current loop stability analysis without GVFR, system poles distribution is analytically studied in z-domain, the critical frequency is therefore...... calculated as well as the control gain limit. Then, this paper reveals the GVFR would change the system stability in the weak power system, two frequency boundaries and three typical resonance frequency ranges are identified and compared. System poles distribution shows that GVFR can offer damping effects...

  6. Grid Voltage Modulated Control of Grid-Connected Voltage Source Inverters under Unbalanced Grid Conditions

    DEFF Research Database (Denmark)

    Li, Mingshen; Gui, Yonghao; Quintero, Juan Carlos Vasquez

    2017-01-01

    In this paper, an improved grid voltage modulated control (GVM) with power compensation is proposed for grid-connected voltage inverters when the grid voltage is unbalanced. The objective of the proposed control is to remove the power ripple and to improve current quality. Three power compensation...... objectives are selected to eliminate the negative sequence components of currents. The modified GVM method is designed to obtain two separate second-order systems for not only the fast convergence rate of the instantaneous active and reactive powers but also the robust performance. In addition, this method...

  7. Low-voltage grid-connection of photovoltaic power systems

    Energy Technology Data Exchange (ETDEWEB)

    Collinson, A.; Thornycroft, J.

    1999-07-01

    This report summarises the results of a project aimed at developing technical guidelines concerning grid connected photovoltaic (PV) inverter generators which are to be published in draft form as the {sup U}K Technical Guidelines for Inverter Connected Single Phase Photovoltaic (PV) Generators up to 5kVA{sup .} The background to the use of PV in the UK is traced, and the technical criteria for electrical integration of PV systems, and UK guidelines for grid connected PV systems are examined. The findings of the working group of the International Energy Agency (IEA) Implementing Agreement on Photovoltaic Power Systems are also presented in this report. Appendices discuss the UK technical guidelines, the IEA Task V activities,, utility aspects of grid-connected PV systems, and demonstration tests on grid-connected PV systems, and lists Task V reports.

  8. Firefighter Safety for PV Systems

    DEFF Research Database (Denmark)

    Mathe, Laszlo; Sera, Dezso; Spataru, Sergiu

    2015-01-01

    An important and highly discussed safety issue for photovoltaic (PV) systems is that as long as the PV panels are illuminated, a high voltage is present at the PV string terminals and cables between the string and inverters that is independent of the state of the inverter's dc disconnection switch...

  9. Compensation techniques for non-linearities in H-bridge inverters

    Directory of Open Access Journals (Sweden)

    Daniel Zammit

    2016-12-01

    Full Text Available This paper presents compensation techniques for component non-linearities in H-bridge inverters as those used in grid-connected photovoltaic (PV inverters. Novel compensation techniques depending on the switching device current were formulated to compensate for the non-linearities in inverter circuits caused by the voltage drops on the switching devices. Both simulation and experimental results will be presented. Testing was carried out on a PV inverter which was designed and constructed for this research. Very satisfactory results were obtained from all the compensation techniques presented, however the exact compensation method was the most effective, providing the highest reduction in harmonics.

  10. Mission Profile Translation to Capacitor Stresses in Grid-Connected Photovoltaic Systems

    DEFF Research Database (Denmark)

    Yang, Yongheng; Ma, Ke; Wang, Huai

    2014-01-01

    DC capacitors are widely adopted in grid-connected PhotoVoltaic(PV) systems for power stabilization and control decoupling. They have become one of the critical components in grid-connected PV inverters in terms of cost, reliability and volume. The electrical and thermal stresses of the DC...... stresses of the DC capacitors under both normal and abnormal grid conditions. As a consequence, this investigation provides new insights into the sizing and reliability prediction of those capacitors with respect to priorart studies. Two study cases on a single-stage PV inverter and a two-stage PV inverter...

  11. Reviewing the potential and cost-effectiveness of grid-connected solar PV in Indonesia on a provincial level

    NARCIS (Netherlands)

    Veldhuis, A.J.; Reinders, Angelina H.M.E.

    2013-01-01

    Photovoltaic (PV) energy could play a large role in increasing the electrification ratio and decreasing greenhouse gas emissions in Indonesia, especially since Indonesia comprises over 17,000 islands which is a challenge for the distribution of fuels and modern grid connection. The potential of

  12. Effects of silicon carbide MOSFETs on the efficiency and power quality of a microgrid-connected inverter

    International Nuclear Information System (INIS)

    Ding, Xiaofeng; Chen, Feida; Du, Min; Guo, Hong; Ren, Suping

    2017-01-01

    Highlights: •The characteristics comparison between SiC-inverter and Si-inverter is implemented, considering thermal effects. •The voltage distortion of inverters is modeling from the perspective of the behaviors of the device. •The efficiency of the microgrid-connected inverter has been greatly increased by replacing Si with SiC. •The SiC microgrid-connected inverter has smaller voltage distortion and less harmonic current than those of Si-inverter. •The proposed analytical model has been validated by the experimental test. -- Abstract: With the expanding power demands and increasing use of renewable energy resources, microgrids have been widely supported. Wide bandgap semiconductor devices with higher blocking voltage capabilities and higher switching speeds, such as silicon carbide (SiC) devices, will become a critical component in building microgrids. This paper describes a comprehensive investigation of the effects of SiC Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) on the efficiency and power quality of the inverters used in low voltage microgrids compared with conventional inverters based on silicon (Si) Insulated-gate Bipolar Transistors (IGBTs). First, the characteristics of both SiC and Si are measured by a double pulse test (DPT), considering thermal effects. Then, conduction and switching losses under different temperatures are calculated based on DPT results. Second, phase voltage distortions are modeled and calculated according to the tested switching and conduction characteristics of SiC, resulting in harmonic components in the phase current. Finally, an experiment is implemented. The experimental results show that the SiC-inverter greatly increases the energy efficiency and improves the power quality in the microgrid; these results are consistent with the analytical results.

  13. Robust Grid-Current-Feedback Resonance Suppression Method for LCL-Type Grid-Connected Inverter Connected to Weak Grid

    DEFF Research Database (Denmark)

    Zhou, Xiaoping; Zhou, Leming; Chen, Yandong

    2018-01-01

    In this paper, a robust grid-current-feedback reso-nance suppression (GCFRS) method for LCL-type grid-connected inverter is proposed to enhance the system damping without introducing the switching noise and eliminate the impact of control delay on system robustness against grid-impedance variation....... It is composed of GCFRS method, the full duty-ratio and zero-beat-lag PWM method, and the lead-grid-current-feedback-resonance-suppression (LGCFRS) method. Firstly, the GCFRS is used to suppress the LCL-resonant peak well and avoid introducing the switching noise. Secondly, the proposed full duty-ratio and zero......-beat-lag PWM method is used to elimi-nate the one-beat-lag computation delay without introducing duty cycle limitations. Moreover, it can also realize the smooth switching from positive to negative half-wave of the grid current and improve the waveform quality. Thirdly, the proposed LGCFRS is used to further...

  14. Analysis and Design of Improved Weighted Average Current Control Strategy for LCL-Type Grid-Connected Inverters

    DEFF Research Database (Denmark)

    Han, Yang; Li, Zipeng; Yang, Ping

    2017-01-01

    The LCL grid-connected inverter has the ability to attenuate the high-frequency current harmonics. However, the inherent resonance of the LCL filter affects the system stability significantly. To damp the resonance effect, the dual-loop current control can be used to stabilize the system. The grid...... Control Strategy for LCL-Type Grid-Connected Inverters. Available from: https://www.researchgate.net/publication/313734269_Analysis_and_Design_of_Improved_Weighted_Average_Current_Control_Strategy_for_LCL-Type_Grid-Connected_Inverters [accessed Apr 20, 2017]....... current plus capacitor current feedback system is widely used for its better transient response and high robustness against the grid impedance variations. While the weighted average current (WAC) feedback scheme is capable to provide a wider bandwidth at higher frequencies but show poor stability...

  15. Decentralized electricity generation by using photovoltaic grid-connected solar system

    International Nuclear Information System (INIS)

    Tyutyundziev, N.; Vitanov, P.; Radkov, R.; Grottke, M.

    2006-01-01

    AcadPV is the first demonstration installation connected permanently to LV grid in Sofia, Bulgaria aiming at assessment of PV efficiencies and cost-effectiveness. A thorough analysis has been carried out in order to select PV system site, supporting construction design and orientation. The PV generator is divided to 3 PV subfields equipped by 3 SUNPOWER inverters connected to 3 separated phases of the grid. The performance of 10kWp PV system has been evaluated during the first year of operation and compared to PV simulation software results

  16. Commercialization and business development of grid-connected PV at SMUD

    International Nuclear Information System (INIS)

    Osborn, D.E.

    1998-01-01

    SMUD has completed its first 5 year, 6 MW PV commercialization effort based on the sustained, orderly development of the utility PV market. SMUD has begun a 5 year, 10 MW program designed to complete a process that will result in PV being at a market competitive price by 2002 and as a sustainable business opportunity for SMUD. As part of this effort, by the end of 1997, SMUD had installed over 450 PV systems totaling 6 MW. These included over 420 residential rooftop systems as well as commercial buildings, parking lots and substation systems. Under its new Business Plan, SMUD has signed contracts for an additional 10 MW of PV systems for 1998 through 2002 with cost decreasing to less than $3/W. As part of its new competitive business strategy responding to changes the utility industry is undergoing, SMUD has incorporated PV as a key business opportunity. SMUD has established partnerships with its customers through the PV Pioneer green pricing program, with DOE and UPVG through TEAM-UP and Million Solar Roofs to advance PV commercialization and to develop rooftops as PV power plant sites and with other utilities through its PV Partnership program

  17. Fault Ride Though Control of Photovoltaic Grid-connected Inverter with Current-limited Capability under Offshore Unbalanced Voltage Conditions

    DEFF Research Database (Denmark)

    Liu, Wenzhao; Guo, Xiaoqiang; Savaghebi, Mehdi

    2016-01-01

    The photovoltaic (PV) inverter installed on board experiences the excessive current stress in case of the offshore unbalanced voltage fault ride through (FRT), which significantly affects the operation reliability of the power supply system. In order to solve the problem, the inherent mechanism...... of the excessive current phenomenon with the conventional fault ride through control is discussed. The quantitative analysis of the current peak value is conducted and a new current-limiting control strategy is proposed to achieve the flexible power control and successful fault ride through in a safe current...

  18. An Enhanced Droop Control Scheme for Resilient Active Power Sharing in Paralleled Two-Stage PV Inverter Systems

    DEFF Research Database (Denmark)

    Liu, Hongpeng; Yang, Yongheng; Wang, Xiongfei

    2016-01-01

    Traditional droop-controlled systems assume that the generators are able to provide sufficient power as required. This is however not always true, especially in renewable systems, where the energy sources (e.g., photovoltaic source) may not be able to provide enough power (or even loss of power...... generation) due to the intermittency. In that case, unbalance in active power generation may occur among the paralleled systems. Additionally, most droop-controlled systems have been assumed to be a single dc-ac inverter with a fixed dc input source. The dc-dc converter as the front-end of a two...

  19. The Design of Connection Solid Oxide Fuel Cell (SOFC) Integrated Grid with Three-Phase Inverter

    Science.gov (United States)

    Darjat; Sulistyo; Triwiyatno, Aris; Thalib, Humaid

    2018-03-01

    Fuel cell technology is a relatively new energy-saving technology that has the potential to replace conventional energy technologies. Among the different types of generation technologies, fuel cells is the generation technologies considered as a potential source of power generation because it is flexible and can be placed anywhere based distribution system. Modeling of SOFC is done by using Nernst equation. The output power of the fuel cell can be controlled by controlling the flow rate of the fuels used in the process. Three-phase PWM inverter is used to get the form of three-phase voltage which same with the grid. In this paper, the planning and design of the SOFC are connected to the grid.

  20. Internal-Model-Principle-Based Specific Harmonics Repetitive Controller for Grid-Connected PWM Inverters

    Directory of Open Access Journals (Sweden)

    Wenzhou Lu

    2016-01-01

    Full Text Available This paper analyzes the general properties of IMP-based controller and presents an internal-model-principle-based (IMP-based specific harmonics repetitive control (SHRC scheme. The proposed SHRC is effective for specific nk±m order harmonics, with n>m≥0 and k=0,1,2,…. Using the properties of exponential function, SHRC can also be rewritten into the format of multiple resonant controllers in parallel, where the control gain of SHRC is n/2 multiple of that of conventional RC (CRC. Therefore, including SHRC in a stable closed-loop feedback control system, asymptotic disturbance eliminating, or reference tracking for any periodic signal only including these specific harmonic components at n/2 times faster error convergence rate compared with CRC can be achieved. Application examples of SHRC controlled three-phase/single-phase grid-connected PWM inverters demonstrate the effectiveness and advantages of the proposed SHRC scheme.

  1. Stability Analysis and Active Damping for LLCL-filter-Based Grid-Connected Inverters

    DEFF Research Database (Denmark)

    Huang, Min; Wang, Xiongfei; Loh, Poh Chiang

    2015-01-01

    to use either passive or active damping methods. This paper analyzes the stability of the LLCL-filter based grid-connected inverter and identifies a critical resonant frequency for the LLCL-filter when sampling and transport delays are considered. In a high resonant frequency region the active damping...... is not required but in a low resonant frequency region the active damping is necessary. The basic LLCL resonance damping properties of different feedback states based on a notch filter concept are also studied. Then an active damping method which is using the capacitor current feedback for LLCL......-filter is introduced. Based on this active damping method, a design procedure for the controller is given. Last, both simulation and experimental results are provided to validate the theoretical analysis of this paper....

  2. Estimation of Maximum Allowable PV Connection to LV Residential Power Networks

    DEFF Research Database (Denmark)

    Demirok, Erhan; Sera, Dezso; Teodorescu, Remus

    2011-01-01

    Maximum photovoltaic (PV) hosting capacity of low voltage (LV) power networks is mainly restricted by either thermal limits of network components or grid voltage quality resulted from high penetration of distributed PV systems. This maximum hosting capacity may be lower than the available solar...... potential of geographic area due to power network limitations even though all rooftops are fully occupied with PV modules. Therefore, it becomes more of an issue to know what exactly limits higher PV penetration level and which solutions should be engaged efficiently such as over sizing distribution...

  3. Mission profile based multi-disciplinary analysis of power modules in single-phase transformerless photovoltaic inverters

    DEFF Research Database (Denmark)

    Yang, Yongheng; Wang, Huai; Blaabjerg, Frede

    2013-01-01

    years) has been set as a main target and an emerging demand from the customers, which imposes a new challenge on grid-connected transformerless inverters. In order to reduce maintenance cost, it is essential to predict the lifetime of the transformerless PV inverter and its components based......The popularity of transformerless photovoltaic (PV) inverters in Europe proves that these topologies can achieve higher efficiency (e.g., ≥ 98% has been reported). Along with the advanced power electronics technology and the booming development of PV power systems, a long service time (e.g. 25...... on the mission profiles — solar irradiance and ambient temperature. In this paper, a mission profile based analysis approach is proposed and it is demonstrated by three main single-phase transformerless PV inverters — Full-Bridge (FB) with bipolar modulation scheme, the FB inverter with DC bypass (FB...

  4. Comparison of Different MPPT Algorithms with a Proposed One Using a Power Estimator for Grid Connected PV Systems

    Directory of Open Access Journals (Sweden)

    Manel Hlaili

    2016-01-01

    Full Text Available Photovoltaic (PV energy is one of the most important energy sources since it is clean and inexhaustible. It is important to operate PV energy conversion systems in the maximum power point (MPP to maximize the output energy of PV arrays. An MPPT control is necessary to extract maximum power from the PV arrays. In recent years, a large number of techniques have been proposed for tracking the maximum power point. This paper presents a comparison of different MPPT methods and proposes one which used a power estimator and also analyses their suitability for systems which experience a wide range of operating conditions. The classic analysed methods, the incremental conductance (IncCond, perturbation and observation (P&O, ripple correlation (RC algorithms, are suitable and practical. Simulation results of a single phase NPC grid connected PV system operating with the aforementioned methods are presented to confirm effectiveness of the scheme and algorithms. Simulation results verify the correct operation of the different MPPT and the proposed algorithm.

  5. Effect of Neutral Grounding Protection Methods for Compensated Wind/PV Grid-Connected Hybrid Power Systems

    Directory of Open Access Journals (Sweden)

    Nurettin Çetinkaya

    2017-01-01

    Full Text Available The effects of the wind/PV grid-connected system (GCS can be categorized as technical, environmental, and economic impacts. It has a vital impact for improving the voltage in the power systems; however, it has some negative effects such as interfacing and fault clearing. This paper discusses different grounding methods for fault protection of High-voltage (HV power systems. Influences of these grounding methods for various fault characteristics on wind/PV GCSs are discussed. Simulation models are implemented in the Alternative Transient Program (ATP version of the Electromagnetic Transient Program (EMTP. The models allow for different fault factors and grounding methods. Results are obtained to evaluate the impact of each grounding method on the 3-phase short-circuit fault (SCF, double-line-to-ground (DLG fault, and single-line-to-ground (SLG fault features. Solid, resistance, and Petersen coil grounding are compared for different faults on wind/PV GCSs. Transient overcurrent and overvoltage waveforms are used to describe the fault case. This paper is intended as a guide to engineers in selecting adequate grounding and ground fault protection schemes for HV, for evaluating existing wind/PV GCSs to minimize the damage of the system components from faults. This research presents the contribution of wind/PV generators and their comparison with the conventional system alone.

  6. Visualization of Operational Performance of Grid-Connected PV Systems in Selected European Countries

    Directory of Open Access Journals (Sweden)

    Bala Bhavya Kausika

    2018-05-01

    Full Text Available This paper presents the results of the analyses of operational performance of small-sized residential PV systems, connected to the grid, in the Netherlands and some other European countries over three consecutive years. Web scraping techniques were employed to collect detailed yield data at high time resolution (5–15 min from a large number (31,844 of systems with 741 MWp of total capacity, delivering data continuously for at least one year. Annual system yield data was compared from small and medium-sized installations. Cartography and spatial analysis techniques in a geographic information system (GIS were used to visualize yield and performance ratio, which greatly facilitates the assessment of performance for geographically scattered systems. Variations in yield and performance ratios over the years were observed with higher values in 2015 due to higher irradiation values. The potential of specific yield and performance maps lies in the updating of monitoring databases, quality control of data, and availability of irradiation data. The automatic generation of performance maps could be a trend in future mapping.

  7. Impact of Reactive Power Injection Outside Feed-In Hours on the Reliability of Photovoltaic Inverters

    DEFF Research Database (Denmark)

    Anurag, Anup; Yang, Yongheng; Blaabjerg, Frede

    2015-01-01

    , the analysis enables the translation from long-term mission profiles to device thermal loading, considering the operation at night. An analytical lifetime model is then used for lifetime quantization based on the Palgrem Miner rule. Thereafter, considering the lifetime reduction of the PV inverter......Current energy paradigm of mixed renewables seems to urgently require reactive power provision at various feed-in points of the utility grid. Photovoltaic (PV) inverters are able to provide reactive power in a decentralized manner at the grid-connection point even outside active power feed......-in operation, especially at night. This serves as a motivation for utilizing the PV inverters at night for reactive power compensation. Thus, a detailed analysis on the impact of reactive power injection by PV inverters outside feed-in operation on the thermal performance and also the reliability is performed...

  8. Coordinated Control of Multifunctional Inverters for Voltage Support and Harmonic Compensation in a Grid-Connected Microgrid

    DEFF Research Database (Denmark)

    Mousazadeh, Seyyed Yousef; Jalilian, Alireza; Savaghebi, Mehdi

    2018-01-01

    In this paper, a coordinated harmonic compensation and voltage support scheme is presented for distributed generations’ (DGs’) interface inverters in a resistive grid-connected microgrid. Voltage support is performed by reactive power compensation which can mitigate the over/under voltage problem...

  9. Evaluation of cooperation WPP and PV connected through the shared transformer to the network 22kV

    Directory of Open Access Journals (Sweden)

    Tomas Sumbera

    2012-01-01

    Full Text Available The article deals with evaluation the cooperation possibility of wind and solar power plants connected through the common transformator to the 22kV network. Cooperation evaluation is, based on measured data, for wind power plant about installed capacity 2MW and for solar power plant about installed capacity 1,1MWp. In the next part of this article there is the analysis of suitable localities for construction of „hybrid system (WPP+PV“ in the Czech Republic. The last part of the article deals with analysis of active power fluctuation of individuals electric sources compared with system WPP+PV and with evaluation the effects after system connection WPP+PV to the 22kV network.

  10. Fire resistant PV shingle assembly

    Science.gov (United States)

    Lenox, Carl J.

    2012-10-02

    A fire resistant PV shingle assembly includes a PV assembly, including PV body, a fire shield and a connection member connecting the fire shield below the PV body, and a support and inter-engagement assembly. The support and inter-engagement assembly is mounted to the PV assembly and comprises a vertical support element, supporting the PV assembly above a support surface, an upper interlock element, positioned towards the upper PV edge, and a lower interlock element, positioned towards the lower PV edge. The upper interlock element of one PV shingle assembly is inter-engageable with the lower interlock element of an adjacent PV shingle assembly. In some embodiments the PV shingle assembly may comprise a ventilation path below the PV body. The PV body may be slidably mounted to the connection member to facilitate removal of the PV body.

  11. High-Performance Constant Power Generation in Grid-Connected PV Systems

    DEFF Research Database (Denmark)

    Sangwongwanich, Ariya; Yang, Yongheng; Blaabjerg, Frede

    2016-01-01

    An advanced power control strategy by limiting the maximum feed-in power of PV systems has been proposed, which can ensure a fast and smooth transition between maximum power point tracking and Constant Power Generation (CPG). Regardless of the solar irradiance levels, high-performance and stable...... operation are always achieved by the proposed control strategy. It can regulate the PV output power according to any set-point, and force the PV systems to operate at the left side of the maximum power point without stability problems. Experimental results have verified the effectiveness of the proposed CPG...

  12. Investigation of the sideband effect for the LCL-type grid-connected inverter with high LCL resonance frequency

    DEFF Research Database (Denmark)

    Yang, Dongsheng; Wang, Xiongfei; Blaabjerg, Frede

    2017-01-01

    The LCL-type grid connected inverter has been widely used as the intelligent power interface between the distributed generation unit and the power grid. To reduce the cost and volume of the filter, it is desirable to design the LCL filter with higher resonance frequency provided that the quality...... of injected grid current is not compromised. Actually, it is the typical case for the T-type or NPC three-level inverter to design its LCL resonance frequency close to half of the switching frequency. In this case, however, the sideband effect of SPWM modulation can impose a significant impact on the system...

  13. Grid Connection of Wave Power Farm Using an N-Level Cascaded H-Bridge Multilevel Inverter

    Directory of Open Access Journals (Sweden)

    Rickard Ekström

    2013-01-01

    Full Text Available An N-level cascaded H-bridge multilevel inverter is proposed for grid connection of large wave power farms. The point-absorber wave energy converters are individually rectified and used as isolated DC-sources. The variable power characteristics of the wave energy converters are discussed, and a method of mitigating this issue is demonstrated. The complete power control system is given in detail and has been experimentally verified for a single-phase setup of the 9-level inverter. Theoretical expressions of the power sharing between multilevel cells are derived and show good correspondence with the experimental results.

  14. Adaptive Harmonic Compensation in Residential Distribution Grid by Roof-Top PV Systems

    DEFF Research Database (Denmark)

    Zangeneh Bighash, Esmaeil; Sadeghzadeh, Seyed Mohammad; Ebrahimzadeh, Esmaeil

    2018-01-01

    grid- connected roof-top PV inverters in residential distribution grid can be an opportunity to engage these systems in the power quality issues as custom power devices. By implementing a proper control for roof-top PV inverters, these systems may in addition to inject the fundamental current......, additionally act like a virtual harmonic resistance and dedicate their additional current capacity to compensate the harmonics of residential distribution grid. In this paper, each roof-top PV system is a grid harmonic supervisor, where it continually measures the PCC voltage harmonics by Sliding Discrete...

  15. A study on economic power dispatch grid connected PV power plant in educational institutes

    Science.gov (United States)

    Singh, Kuldip; Kumar, M. Narendra; Mishra, Satyasis

    2018-04-01

    India has main concerns on environment and escalation of fuel prices with respect to diminution of fossil fuel reserves and the major focus on renewable Energy sources for power generation to fulfill the present and future energy demand. Installation of PV power plants in the Educational Institutions has grown up drastically throughout India. More PV power plant are integrated with load and grid through net metering. Therefore, this paper is an analysis of the 75kWp PV plant at chosen buses, considering the need of minimum demand from the grid. The case study is carried out for different generation level throughout the day and year w.r.t load and climate changes, load sharing on grid. The economic dispatch model developed for PV plant integrated with Grid.

  16. Control Aspects of a LCL Grid-Connected Green Power Inverter

    DEFF Research Database (Denmark)

    Kjær, Søren Bækhøj; Andersen, Gert Karmisholt; Klumpner, Christian

    2002-01-01

    A full-bridge inverter for interfacing the utility grid is developed for using in a Green Power Inverter application. The inverter is feed from an arbitrary green power source (fuel cell, photovoltaic, small wind turbine etc.) through a rectifier into the dc-link. In order to maintain a sinusoidal...... grid current with low harmonic distortion and a high power factor, the inverter is controlled to emulate a negative resistance towards the grid. The size of the emulated resistor is determined by the dc-link voltage controller, which tries to maintain a constant dc-link voltage. This is however...

  17. Improvement of the grid-connect current quality using novel proportional-integral controller for photovoltaic inverters.

    Science.gov (United States)

    Cheng, Yuhua; Chen, Kai; Bai, Libing; Yang, Jing

    2014-02-01

    Precise control of the grid-connected current is a challenge in photovoltaic inverter research. Traditional Proportional-Integral (PI) control technology cannot eliminate steady-state error when tracking the sinusoidal signal from the grid, which results in a very high total harmonic distortion in the grid-connected current. A novel PI controller has been developed in this paper, in which the sinusoidal wave is discretized into an N-step input signal that is decided by the control frequency to eliminate the steady state error of the system. The effect of periodical error caused by the dead zone of the power switch and conduction voltage drop can be avoided; the current tracking accuracy and current harmonic content can also be improved. Based on the proposed PI controller, a 700 W photovoltaic grid-connected inverter is developed and validated. The improvement has been demonstrated through experimental results.

  18. Environmental life cycle assessment of a large-scale grid-connected PV power plant. Case study Moura 62 MW PV power plant

    Energy Technology Data Exchange (ETDEWEB)

    Suomalainen, Kiti

    2006-01-15

    An environmental life cycle assessment has been conducted for a 62 MW grid-connected photovoltaic installation to study the role of BOS components in the total environmental load. Also the influence of the current electricity supply has been investigated. For an alternative approach a net output approach has been used, where all electricity requirements are supplied by the photovoltaic installation itself. The components taken into account are monocrystalline silicon cells in frameless modules, steel support structures in concrete foundations, inverters, transformers, cables, transports and construction of roads and buildings. For stationary inert products without intrinsic energy requirements, such as cables, inverters, support structures etc., only raw material acquisition and processing are taken into account, since they are considered the most dominant stages in the life cycle. The results confirm a minor environmental load from BOS components compared to the module life cycle, showing approximately ten to twenty percent impact of the total. Uncertainties lie in the approximations for electronic devices as well as in the emissions from silicon processing. Concerning the electricity supply, the results differ considerably depending on which system perspective is used. In the net output approach the impacts decrease with approximately ninety percent from the traditional approach. Some increases are also shown in toxicity categories due to the increased module production needed for the enlargement of the installation.

  19. A Fuzzy-Based PI Controller for Power Management of a Grid-Connected PV-SOFC Hybrid System

    Directory of Open Access Journals (Sweden)

    Shivashankar Sukumar

    2017-10-01

    Full Text Available Solar power generation is intermittent in nature. It is nearly impossible for a photovoltaic (PV system to supply power continuously and consistently to a varying load. Operating a controllable source like a fuel cell in parallel with PV can be a solution to supply power to variable loads. In order to coordinate the power supply from fuel cells and PVs, a power management system needs to be designed for the microgrid system. This paper presents a power management system for a grid-connected PV and solid oxide fuel cell (SOFC, considering variation in the load and solar radiation. The objective of the proposed system is to minimize the power drawn from the grid and operate the SOFC within a specific power range. Since the PV is operated at the maximum power point, the power management involves the control of SOFC active power where a proportional and integral (PI controller is used. The control parameters of the PI controller Kp (proportional constant and Ti (integral time constant are determined by the genetic algorithm (GA and simplex method. In addition, a fuzzy logic controller is also developed to generate appropriate control parameters for the PI controller. The performance of the controllers is evaluated by minimizing the integral of time multiplied by absolute error (ITAE criterion. Simulation results showed that the fuzzy-based PI controller outperforms the PI controller tuned by the GA and simplex method in managing the power from the hybrid source effectively under variations of load and solar radiation.

  20. Applying the min-projection strategy to improve the transient performance of the three-phase grid-connected inverter.

    Science.gov (United States)

    Baygi, Mahdi Oloumi; Ghazi, Reza; Monfared, Mohammad

    2014-07-01

    Applying the min-projection strategy (MPS) to a three-phase grid-connected inverter to improve its transient performance is the main objective of this paper. For this purpose, the inverter is first modeled as a switched linear system. Then, the feasibility of the MPS technique is investigated and the stability criterion is derived. Hereafter, the fundamental equations of the MPS for the control of the inverter are obtained. The proposed scheme is simulated in PSCAD/EMTDC environment. The validity of the MPS approach is confirmed by comparing the obtained results with those of VOC method. The results demonstrate that the proposed method despite its simplicity provides an excellent transient performance, fully decoupled control of active and reactive powers, acceptable THD level and a reasonable switching frequency. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  1. A Riding-through Technique for Seamless Transition between Islanded and Grid-Connected Modes of Droop-Controlled Inverters

    DEFF Research Database (Denmark)

    Hu, Shang-hung; Lee, Tzung-Lin; Kuo, Chun-Yi

    2016-01-01

    This paper presents a seamless transition method for a droop-controlled inverter. The droop control is suitable to make the inverter work as a voltage source in both islanded and grid-connected modes, however, the transfer between theses modes can result in a big inrush current that may damage...... a smooth transition between them, requiring neither synchronization signals nor grid-side information. The control algorithm and design procedure are presented. Experimental results from a laboratory prototype validate the effectiveness of the proposed method....... the system. The proposed method allows the droop-controlled inverter to improve the transient response when transferring between modes, by detecting the inrush current, activating a current control loop during transients, and then transferring back to droop-controlled mode smoothly by using a virtual...

  2. Online Optimal Switching Frequency Selection for Grid-Connected Voltage Source Inverters

    Directory of Open Access Journals (Sweden)

    Saher Albatran

    2017-12-01

    Full Text Available Enhancing the performance of the voltage source inverters (VSIs without changing the hardware structure has recently acquired an increased amount of interest. In this study, an optimization algorithm, enhancing the quality of the output power and the efficiency of three-phase grid connected VSIs is proposed. Towards that end, the proposed algorithm varies the switching frequency (fsw to maintain the best balance between switching losses of the insulated-gate-bipolar-transistor (IGBT power module as well as the output power quality under all loading conditions, including the ambient temperature effect. Since there is a contradiction with these two measures in relation to the switching frequency, the theory of multi-objective optimization is employed. The proposed algorithm is executed on the platform of Altera® DE2-115 field-programmable-gate-array (FPGA in which the optimal value of the switching frequency is determined online without the need for heavy offline calculations and/or lookup tables. With adopting the proposed algorithm, there is an improvement in the VSI efficiency without degrading the output power quality. Therefore, the proposed algorithm enhances the lifetime of the IGBT power module because of reduced variations in the module’s junction temperature. An experimental prototype is built, and experimental tests are conducted for the verification of the viability of the proposed algorithm.

  3. Zero-Axis Virtual Synchronous Coordinate Based Current Control Strategy for Grid-Connected Inverter

    Directory of Open Access Journals (Sweden)

    Longyue Yang

    2018-05-01

    Full Text Available Unbalanced power has a great influence on the safe and stable operation of the distribution network system. The static power compensator, which is essentially a grid-connected inverter, is an effective solution to the three-phase power imbalance problem. In order to solve the tracking error problem of zero-sequence AC current signals, a novel control strategy based on zero-axis virtual synchronous coordinates is proposed in this paper. By configuring the operation of filter transmission matrices, a specific orthogonal signal is obtained for zero-axis reconstruction. In addition, a controller design scheme based on this method is proposed. Compared with the traditional zero-axis direct control, this control strategy is equivalent to adding a frequency tuning module by the orthogonal signal generator. The control gain of an open loop system can be equivalently promoted through linear transformation. With its clear mathematical meaning, zero- sequence current control can be controlled with only a first-order linear controller. Through reasonable parameter design, zero steady-state error, fast response and strong stability can be achieved. Finally, the performance of the proposed control strategy is verified by both simulations and experiments.

  4. Grid-connected photovoltaic (PV) systems with batteries storage as solution to electrical grid outages in Burkina Faso

    International Nuclear Information System (INIS)

    Abdoulaye, D; Koalaga, Z; Zougmore, F

    2012-01-01

    This paper deals with a key solution for power outages problem experienced by many African countries and this through grid-connected photovoltaic (PV) systems with batteries storage. African grids are characterized by an insufficient power supply and frequent interruptions. Due to this fact, users who especially use classical grid-connected photovoltaic systems are unable to profit from their installation even if there is sun. In this study, we suggest the using of a grid-connected photovoltaic system with batteries storage as a solution to these problems. This photovoltaic system works by injecting the surplus of electricity production into grid and can also deliver electricity as a stand-alone system with all security needed. To achieve our study objectives, firstly we conducted a survey of a real situation of one African electrical grid, the case of Burkina Faso (SONABEL: National Electricity Company of Burkina). Secondly, as study case, we undertake a sizing, a modeling and a simulation of a grid-connected PV system with batteries storage for the LAME laboratory at the University of Ouagadougou. The simulation shows that the proposed grid-connected system allows users to profit from their photovoltaic installation at any time even if the public electrical grid has some failures either during the day or at night.

  5. Comparative Analysis of Inversors for Small PV Systems Grid Connected; Analisis Comparativo de inversores para la conexion a Red de Pequnos Sistemas Fotovoltaicos

    Energy Technology Data Exchange (ETDEWEB)

    Sidrach de Cardona, M.; Ramirez, L.

    2001-07-01

    The energy produced by a grid connected photovoltaic system is a function of weather conditions, mainly available radiation and temperature, photovoltaic array efficiency and inverter characteristics. The results obtained in experimental measurements with four small grid-connected inverters are described in this work. The main goal is to know the inverter performance in real operation conditions. For this purpose a 2 kW{sub p} photovoltaic system has been used. These results allow us to know both the inverter efficiency and its output power quality. The following parameters have been evaluated as a function of but put inverter power efficiency, point of maximum power tracking, intensity and voltage waveform, total harmonic distortion and harmonic values to 31 order, frequency, power factor and reactive power. Other interesting parameters like stand-by energy consumption and daily losses due to the inverter threshold have also been analyzed. the results allow us to know the inverter features as a function of its real work point. In our comparative study it is possible to observe remarkable differences between the inverters; these results show how important it is to have a unique standard for inverters to photovoltaic grid-connected systems. (Author)

  6. Economic and Environmental Assessment of a 1 MW Grid Connected Rooftop Solar PV System for Energy Efficient Building in Bangladesh

    Science.gov (United States)

    Chakraborty, Sanjib; Hosain, Rubayet; Rahman, Toufiqur; Rabbi, Ahmead Fazle

    This paper evaluates the potentiality of a 1 MW grid connected rooftop solar PV system for an Energy Efficient Building in Bangladesh, which was estimated by utilizing NASA SSE solar radiation data, PVsyst simulation software and RETScreen simulation software. Economic and environmental viability for a ten-storied building with roof area of 6,500 m2 in the Capital City of Bangladesh, Dhaka was assessed by using the RETScreen simulation software. The yearly electricity production of the proposed system was 1,581 MWh estimated by PVsyst where the technical prospective of gird-connected solar PV in Bangladesh was calculated as about 50,174 MW. The economic assessments were determined the simple payback in such a way that the generated electricity first fulfills the demand of the building, and then the rest of the energy is supplied to the grid. The result indicates that the roof top solar PV system for an Energy efficient building in Dhaka city has a favorable condition for development both in economic and environmental point of view.

  7. Technical and economic analysis of grid-connected PV/Wind energy stations in the Republic of Serbia under varying climatic conditions

    OpenAIRE

    Bakić, Vukman V.; Pezo, Milada L.; Stojković, Saša M.

    2016-01-01

    In this paper technical and economic analysis of grid-connected PV/Wind energy systems located in the Republic of Serbia are presented. The technical and economic data, of the various grid-connected PV/Wind hybrid energy systems for three different locations: Novi Sad, Belgrade and Kopaonik, using the transient simulations software TRNSYS and HOMER were obtained. The results obtained in this paper show that locations and technical characteristics of the energy systems have an important influe...

  8. Distributed Storage Inverter and Legacy Generator Integration Plus Renewable Solution for Microgrids

    Science.gov (United States)

    2015-07-01

    Observation ................. 5 2.1.5 PV Inverter with Microgrid Controls .......................................................... 5 2.2 TECHNOLOGY... CONTROL OF PV POWER RAMP RATE FOR GENERATOR STABILITY ..................... 27 6.11 DEMONSTRATION 11: MICROGRID VOLTAGE SUPPORT FROM PV INVERTER...power delivery optimized storage, transiently rated inverters, integration with legacy generator controls , and microgrid compatible inverters for PV

  9. Analysis of the Impacts of Distribution-Connected PV Using High-Speed Data Sets: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Bank, J.; Mather, B.

    2013-03-01

    This paper, presented at the IEEE Green Technologies Conference 2013, utilizes information from high resolution data acquisition systems developed at the National Renewable Energy Laboratory and deployed on a high-penetration PV distribution system to analyze the variability of different electrical parameters. High-resolution solar irradiance data is also available in the same area which is used to characterize the available resource and how it affects the electrical characteristics of the study circuit. This paper takes a data-driven look at the variability caused by load and compares those results against times when significant PV production is present. Comparisons between the variability in system load and the variability of distributed PV generation are made.

  10. Possibilities by using a self-commutated voltage source inverter connected to a weak grid in wind parks

    Energy Technology Data Exchange (ETDEWEB)

    Svensson, Jan [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Electric Power Engineering

    1996-12-01

    In this paper the hybrid wind farm connected to a weak grid is investigated. By combining different electrical wind power plant systems a cost-efficient solution is obtained. The point of common connection voltage level can be controlled by injecting reactive power from a phase-compensating capacitor battery and a voltage source inverter (VSI). If the short-circuit impedance ratio is lower than 1, the demanded reactive power injection to keep the voltage at nominal level is unrealistic. For short-circuit impedance ratios of 2 or higher the demanded reactive power level is acceptable. When using both induction generators and thyristor inverters the reactive power injector VSI size should be about 0.2 pu. If the hybrid farm consists of THYs, IGs and VSIs and the active power is equally shared between the systems, the VSI had to be scaled up by 5% to handle both active and reactive power. 7 refs, 10 figs, 2 tabs

  11. Analysis and Experimental Verification of New Power Flow Control for Grid-Connected Inverter with LCL Filter in Microgrid

    Science.gov (United States)

    Gu, Herong; Guan, Yajuan; Wang, Huaibao; Wei, Baoze; Guo, Xiaoqiang

    2014-01-01

    Microgrid is an effective way to integrate the distributed energy resources into the utility networks. One of the most important issues is the power flow control of grid-connected voltage-source inverter in microgrid. In this paper, the small-signal model of the power flow control for the grid-connected inverter is established, from which it can be observed that the conventional power flow control may suffer from the poor damping and slow transient response. While the new power flow control can mitigate these problems without affecting the steady-state power flow regulation. Results of continuous-domain simulations in MATLAB and digital control experiments based on a 32-bit fixed-point TMS320F2812 DSP are in good agreement, which verify the small signal model analysis and effectiveness of the proposed method. PMID:24672304

  12. Analysis and experimental verification of new power flow control for grid-connected inverter with LCL filter in microgrid.

    Science.gov (United States)

    Gu, Herong; Guan, Yajuan; Wang, Huaibao; Wei, Baoze; Guo, Xiaoqiang

    2014-01-01

    Microgrid is an effective way to integrate the distributed energy resources into the utility networks. One of the most important issues is the power flow control of grid-connected voltage-source inverter in microgrid. In this paper, the small-signal model of the power flow control for the grid-connected inverter is established, from which it can be observed that the conventional power flow control may suffer from the poor damping and slow transient response. While the new power flow control can mitigate these problems without affecting the steady-state power flow regulation. Results of continuous-domain simulations in MATLAB and digital control experiments based on a 32-bit fixed-point TMS320F2812 DSP are in good agreement, which verify the small signal model analysis and effectiveness of the proposed method.

  13. Interaction Admittance Based Modeling of Multi-Paralleled Grid-Connected Inverter with LCL-Filter

    DEFF Research Database (Denmark)

    Lu, Minghui; Blaabjerg, Frede; Wang, Xiongfei

    2016-01-01

    This paper investigates the mutual interaction and stability issues of multi-parallel LCL-filtered inverters. The stability and power quality of multiple grid-tied inverters are gaining more and more research attention as the penetration of renewables increases. In this paper, interactions...... and coupling effects among the multi-paralleled inverters and power grid are explicitly revealed. An Interaction Admittance concept is introduced to express and model the interaction through the physical admittances of the network. Compared to the existing modeling methods, the proposed analysis provides...

  14. Low voltage ride-through capability control for single-stage inverter-based grid-connected photovoltaic power plant

    DEFF Research Database (Denmark)

    Al-Shetwi, Ali Q.; Sujod, Muhamad Zahim; Blaabjerg, Frede

    2018-01-01

    and current limiter are used to absorb the excessive dc-voltage and limits excessive ac current, respectively. This control strategy can also ensure the reactive power support through the injection of reactive current according to the standard requirements as soon as the voltage sag is detected. Furthermore...... to improve the capability of ride-through fault safely and keep the inverter connected, but also to provide grid support through active and reactive power control at different type of faults....

  15. Current control design for three-phase grid-connected inverters using a pole placement technique based on numerical models

    OpenAIRE

    Citro, Costantino; Gavriluta, Catalin; Nizak Md, H. K.; Beltran, H.

    2012-01-01

    This paper presents a design procedure for linear current controllers of three-phase grid-connected inverters. The proposed method consists in deriving a numerical model of the converter by using software simulations and applying the pole placement technique to design the controller with the desired performances. A clear example on how to apply the technique is provided. The effectiveness of the proposed design procedure has been verified through the experimental results obtained with ...

  16. Market Transformation Pathways for Grid-Connected Rooftop Solar PV in Minnesota

    Energy Technology Data Exchange (ETDEWEB)

    Abbey, Ross [Fresh Energy, St. Paul, MN (United States); Ross, Brian [CR Planning, Minneapolis, MN (United States)

    2013-06-03

    This report presents the market and policy findings of the Minnesota Solar Challenge program. The report draws on information collected from state agencies, local government units, solar industry participants, rooftop photovoltaic (PV) adopters (sometimes called customer-generators), state and national experts, the Commerce distributed generation stakeholder process, and the numerous reports and data sets referenced herein.

  17. Co-ordinated experimental research into PV power interaction with the supply network - Phase 2

    Energy Technology Data Exchange (ETDEWEB)

    Hacker, R.; Thornycroft, J.; Knight, J.

    2000-07-01

    This report describes the development of a procedure for type testing photovoltaic inverters that are suitable for connecting to the UK public distribution system based on experimental research and consultation within the industry. Phase 1 of the project investigated the performance of the inverters and the cumulative effect of multiple installation on a section of distributed network, and Phase 2 concentrated on the requirements for PV inverters that would allow them to be connected to the grid without further investigation and to develop a type test procedure. The production of the 'UK Technical Guidelines for Inverter Connected Single Phase Photovoltaic (PV) Generators up to 5kVA' based on the project results and its adoption by the Electricity Association as draft Engineering Recommendations G77 are reported.

  18. Study of electrical and thermal characteristics of inverters for grid-connected photovoltaic systems; Estudo de caracteristicas eletricas e termicas de inversores para sistemas fotovoltaicos conectados a rede

    Energy Technology Data Exchange (ETDEWEB)

    Rampinelli, Giuliano Arns

    2010-12-15

    Grid-connected photovoltaic systems directly convert solar energy into electrical energy delivering to the distribution grid a clean and renewable energy. These systems are basically formed by an array of photovoltaic modules and inverters. The inverters are responsible for converting direct current to alternating current. A study of electrical and thermal characteristics of inverters used in grid-connected photovoltaic systems from a theoretical and experimental analysis. The inverters tests were carried out in two stages: the first stage was performed at Solar Energy Lab. of the Federal University of Rio Grande do Sul (UFRGS), Brazil, where it was used a 4,8 kW{sub p} grid-connected photovoltaic system and ten inverters of different manufacturers. The inverters electrical characteristics measured and analyzed were: direct current to alternating current conversion efficiency, maximum power point tracker efficiency, power factor and harmonic distortion in current and voltage. Inverters thermal testing was also conducted and its results are presented ana analyzed. The second stage of the experimental tests was performed at Photovoltaic Solar Energy Lab. at CIEMAT in Spain. It was used 3 kW{sub p} photovoltaic system and seven inverters of different manufacturers. The inverters are single-phase, up to 5 kW and different topologies (high frequency transformer, low frequency transformer and transformerless). The influence of DC voltage input in the behavior of DC to AC conversion efficiency and power factor was analyzed. The results of the tests allowed the development of mathematical models that describe the electrical and thermal behavior of the inverters. The proposed mathematical models were inserted into computer simulation software developed at UFRGS named FVConect. The evolution of the simulation results compared to the experimental results validates the proposed models. The analysis of the behavior of the inverters improves the understanding of the operating os

  19. Control of Grid Connected Photovoltaic System Using Three-Level T-Type Inverter

    Science.gov (United States)

    Zorig, Abdelmalik; Belkeiri, Mohammed; Barkat, Said; Rabhi, Abdelhamid

    2016-08-01

    Three-level T-Type inverter (3LT2I) topology has numerous advantageous compared to three-level neutral-point-clamped (NPC) inverter. The main benefits of 3LT2I inverter are the efficiency, inverter cost, switching losses, and the quality of output voltage waveforms. In this paper, a photovoltaic distributed generation system based on dual-stage topology of DC-DC boost converter and 3LT2I is introduced. To that end, a decoupling control strategy of 3LT2I is proposed to control the current injected into the grid, reactive power compensation, and DC-link voltage. The resulting system is able to extract the maximum power from photovoltaic generator, to achieve sinusoidal grid currents, and to ensure reactive power compensation. The voltage-balancing control of two split DC capacitors of the 3LT2I is achieved using three-level space vector modulation with balancing strategy based on the effective use of the redundant switching states of the inverter voltage vectors. The proposed system performance is investigated at different operating conditions.

  20. Performance of grid-tied PV facilities: A case study based on real data

    International Nuclear Information System (INIS)

    Díez-Mediavilla, M.; Dieste-Velasco, M.I.; Rodríguez-Amigo, M.C.; García-Calderón, T.; Alonso-Tristán, C.

    2013-01-01

    Highlights: • A new procedure to analyse the performance of PV facilities is presented. • It only requires limited amounts of data that are easily sourced. • Data sets on production were collected over two complete years. • The transformerless inverter outperforms the isolated inverter. - Abstract: A new procedure is presented to analyse the performance of grid-tied PV facilities. It needs limited amounts of data that are easily sourced and is based on knowledge of the analysed system and its mode of operation. The procedure is applied, in a case study, to compare real PV production at two 100 kW p grid-connected PV installations. Located in the same geographical region, the installation of these two facilities followed the same construction criteria – PV panels, panel support system and wiring – and the facilities were exposed to the same atmospheric temperature and solar radiation. They differ with regard to their inverter technology: one facility uses an inverter with an integrated transformer system and the other uses a transformerless inverter. The results show that the transformerless inverter system performed better than the isolated system by a factor of 1.2%, which, in economic terms, represents more than 2000 €/year

  1. A novel harmonic current sharing control strategy for parallel-connected inverters

    DEFF Research Database (Denmark)

    Guan, Yajuan; Guerrero, Josep M.; Savaghebi, Mehdi

    2017-01-01

    A novel control strategy which enables proportional linear and nonlinear loads sharing among paralleled inverters and voltage harmonic suppression is proposed in this paper. The proposed method is based on the autonomous currents sharing controller (ACSC) instead of conventional power droop control...... to provide fast transient response, decoupling control and large stability margin. The current components at different sequences and orders are decomposed by a multi-second-order generalized integrator-based frequency locked loop (MSOGI-FLL). A harmonic-orthogonal-virtual-resistances controller (HOVR......) is used to proportionally share current components at different sequences and orders independently among the paralleled inverters. Proportional resonance controllers tuned at selected frequencies are used to suppress voltage harmonics. Simulations based on two 2.2 kW paralleled three-phase inverters...

  2. Studying the effect of over-modulation on the output voltage of three-phase single-stage grid-connected boost inverter

    Directory of Open Access Journals (Sweden)

    A. Abbas Elserougi

    2013-09-01

    Full Text Available Voltage boosting is very essential issue in renewable-energy fed applications. The classical two-stage power conversion process is typically used to interface the renewable energy sources to the grid. For better efficiency, single-stage inverters are recommended. In this paper, the performance of single-stage three-phase grid-connected boost inverter is investigated when its gain is extended by employing over-modulation technique. Using of over-modulation is compared with the employment of third order harmonic injection. The latter method can increase the inverter gain by 15% without distorting the inverter output voltage. The performance of extended gain grid-connected boost inverter is also tested during normal operation as well as in the presence of grid side disturbances. Simulation and experimental results are satisfactory.

  3. A Highly Robust Single-Loop Current Control Scheme for Grid-Connected Inverter with an Improved LCCL Filter Configuration

    DEFF Research Database (Denmark)

    Pan, Donghua; Ruan, Xinbo; Wang, Xiongfei

    2018-01-01

    Single-loop current control is an attractive scheme for the LCL-type grid-connected inverter due to its simplicity and low cost. However, conventional single-loop control schemes, which command either the inverter current or the grid current, are subject to the specific resonance frequency regions....... The weighted average current control, which splits the filter capacitor into two parts (in form of an LCCL filter) and commands the current flowing between these two parts, is independent of the resonance frequency, but on the other hand, it is limited by the poor sensitivity to the grid impedance variation...... and weak stability in the grid current. These limitations are comprehensively explained in this paper and then addressed by identifying that the single-loop weighted average current control is equivalent to the dual-loop grid current control with an inherent capacitor current active damping. By tuning...

  4. Control Architecture for Parallel-Connected Inverters in Uninterruptible Power Systems

    DEFF Research Database (Denmark)

    Zhang, Chi; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez

    2016-01-01

    bus. The proposed control scheme comprises two layers: (i) a local layer that contains a “reactive power-to-phase droop” in order to synchronize the phase angle of each inverter and a virtual resistance loop that guarantees equal power sharing among inverters; and (ii) a central controller...... that guarantees synchronization with an external real/fictitious utility, and critical bus voltage amplitude restoration. Improved transient and steady-state frequency, active, reactive and harmonic power sharing, and global phase-locked loop resynchronization capability are achieved. Detailed system topology...

  5. Investigating the Impact of Shading Effect on the Characteristics of a Large-Scale Grid-Connected PV Power Plant in Northwest China

    Directory of Open Access Journals (Sweden)

    Yunlin Sun

    2014-01-01

    Full Text Available Northwest China is an ideal region for large-scale grid-connected PV system installation due to its abundant solar radiation and vast areas. For grid-connected PV systems in this region, one of the key issues is how to reduce the shading effect as much as possible to maximize their power generation. In this paper, a shading simulation model for PV modules is established and its reliability is verified under the standard testing condition (STC in laboratory. Based on the investigation result of a 20 MWp grid-connected PV plant in northwest China, the typical shading phenomena are classified and analyzed individually, such as power distribution buildings shading and wire poles shading, plants and birds droppings shading, and front-row PV arrays shading. A series of experiments is also conducted on-site to evaluate and compare the impacts of different typical shading forms. Finally, some feasible solutions are proposed to avoid or reduce the shading effect of PV system during operation in such region.

  6. H-Bridge Transformerless Inverter with Common Ground for Single-Phase Solar-Photovoltaic System

    DEFF Research Database (Denmark)

    Siwakoti, Yam Prasad; Blaabjerg, Frede

    2017-01-01

    This paper proposes a new single-phase H-Bridge transformerless inverter with common ground for grid-connected photovoltaic systems (hereafter it is called ‘Siwakoti-H’ inverter). The inverter works on the principle of flying capacitor and consists of only four power switches (two reverse blocking...... IGBT's (RB-IGBT) and two MOSFET's), a capacitor and a small filter at the output stage. The proposed topology share a common ground with the grid and the PV source. A Unipolar Sinusoidal Pulse-Width Modulation (SPWM) technique is used to modulate the inverter to minimize switching loss, output current...

  7. Precise Modeling Based on Dynamic Phasors for Droop-Controlled Parallel-Connected Inverters

    DEFF Research Database (Denmark)

    Wang, L.; Guo, X.Q.; Gu, H.R.

    2012-01-01

    This paper deals with the precise modeling of droop controlled parallel inverters. This is very attractive since that is a common structure that can be found in a stand-alone droopcontrolled MicroGrid. The conventional small-signal dynamic is not able to predict instabilities of the system, so...

  8. Impact of grid impedance variations on harmonic emission of grid-connected inverters

    DEFF Research Database (Denmark)

    Hoseinzadeh, Bakhtyar; Bak, Claus Leth; Blaabjerg, Frede

    2017-01-01

    This paper addresses harmonic magnification due to resonance circuits resulting from interaction between uncertain grid impedance and converter. The source of harmonic may be either the grid or inverter. It is demonstrated that unknown and unpredictable grid impedance may result in variable...

  9. Analysis, Design and Implementation of a Quasi-Proportional-Resonant Controller for a Multifunctional Capacitive-Coupling Grid-Connected Inverter

    DEFF Research Database (Denmark)

    Ye, Tao; Dai, Ning-Yi; Lam, Chi-Seng

    2016-01-01

    to compensate reactive power and transfer active power simultaneously. It is a promising solution for micro-grid and building-integrated distributed generator systems. A quasiproportional- resonant (quasi-PR) controller is applied to reduce steady-state current tracking errors of the CGCI in this paper......The capacitive-coupling grid-connected inverter (CGCI) is coupled to the point of common coupling via a second-order LC branch. Its operational voltage is much lower than that of a conventional inductive-coupling grid-connected inverter (IGCI) when it serves as a multifunctional inverter...... tracking errors are greatly reduced when the quasi-PR controller rather than the proportional-integration controller is applied. Experimental results are also provided to validate the CGCI as a multifunctional grid-connected inverter....

  10. Reliability assessment platform for the power semiconductor devices - Study case on 3-phase grid-connected inverter application

    DEFF Research Database (Denmark)

    Vernica, Ionut; Ma, Ke; Blaabjerg, Frede

    2017-01-01

    provide valuable reliability information based on given mission profiles and system specification is first developed and its main concept is presented. In order to facilitate the test and access to the loading and lifetime information of the power devices, a novel mission profile based stress emulator...... experimental setup is proposed and designed. The link between the stress emulator setup and the reliability tool software is highlighted. Finally, the reliability assessment platform is demonstrated on a 3-phase grid-connected inverter application study case....

  11. General Unified Integral Controller with Zero Steady-State Error for Single-Phase Grid-Connected Inverters

    DEFF Research Database (Denmark)

    Guo, Xiaoqiang; Guerrero, Josep M.

    2016-01-01

    Current regulation is crucial for operating single-phase grid-connected inverters. The challenge of the current controller is how to fast and precisely tracks the current with zero steady-state error. This paper proposes a novel feedback mechanism for the conventional PI controller. It allows...... done indicates that the widely used PR (P+Resonant) control is just a special case of the proposed control solution. The time-domain simulation in Matlab/Simulink and experimental results from a TMS320F2812 DSP based laboratory prototypes are in good agreement, which verify the effectiveness...

  12. Flexible Power Regulation and Current-limited Control of Grid-connected Inverter under Unbalanced Grid Voltage Faults

    DEFF Research Database (Denmark)

    Guo, Xiaoqiang; Liu, Wenzhao; Lu, Zhigang

    2017-01-01

    The grid-connected inverters may experience excessive current stress in case of unbalanced grid voltage Fault Ride Through (FRT), which significantly affects the reliability of the power supply system. In order to solve the problem, the inherent mechanisms of the excessive current phenomenon...... with the conventional FRT solutions are discussed. The quantitative analysis of three phase current peak values are conducted and a novel current-limited control strategy is proposed to achieve the flexible active and reactive power regulation and successful FRT in a safe current operation area with the aim...

  13. Analysis, Control and Experimental Verification of a Single-Phase Capacitive-Coupling Grid-Connected Inverter

    DEFF Research Database (Denmark)

    Dai, Ning-Yi; Zhang, Wen-Chen; Wong, Man-Chung

    2015-01-01

    with the conventional inductive-coupling grid-connected inverter (IGCI), this structure provides an alternative interface for use between a low-voltage DC microgrid and an AC grid. A comparison between the CGCI and the IGCI is performed. It is concluded that the CGCI is able to transfer active power and provide lagging...... of the CGCI remains at approximately of 50% of the peak grid voltage. In addition, a P-unit current controller is proposed for use with the CGCI, as a proportional-integral controller is not suitable. Finally, simulation and experiments show the effectiveness of the proposed approach....

  14. Operational analysis and comparative evaluation of embedded Z-Source inverters

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Gao, F.; Loh, P.C.

    2008-01-01

    ) circuitry connected instead of the generic voltage source inverter (VSI) circuitry. Further proceeding on to the topological variation, parallel embedded Z-source inverters are presented with the detailed analysis of topological configuration and operational principles showing that they are the superior......This paper presents various embedded Z-source (EZ-source) inverters broadly classified as shunt or parallel embedded Z-source inverter. Being different from the traditional Z-source inverter, EZ-source inverters are constructed by inserting dc sources into the X-shaped impedance network so...... that the dc input current flows smoothly during the whole switching period unlike the traditional Z-source inverter. This feature is interesting when PV panels or fuel cells are assumed to power load since the continuous input current flow reduces control complexity of dc source and system design burden...

  15. PLTS Transformerless Tegangan 20 kV menggunakan Cascaded H-Bridge Multilevel Inverter

    Directory of Open Access Journals (Sweden)

    ANGGARA BRAJAMUSTHI

    2018-03-01

    Full Text Available ABSTRAK Aplikasi dari inverter multilevel pada sistem Pusat Listrik Tenaga Surya (PLTS dapat menghilangkan kebutuhan terhadap transformator, sehingga dapat mengurangi biaya investasi, mengurangi kompleksitas instalasi dan menghilangkan rugi-rugi daya transformator. Pada penelitian ini, sebuah inverter dengan topologi Cascaded H-Bridge Multilevel Inverter dirancang agar mampu mengubah tegangan rendah DC dari beberapa Photovoltaic (PV array menjadi tegangan fasa-fasa 20 kV AC. Perancangan menghasilkan sebuah inverter 3 fasa 27-level dimana setiap level masing-masing memiliki PV array, DC-DC boost converter, H-bridge inverter, dan keluaran 3 fasa terhubung dengan filter LCL. Setiap komponen dari inverter dan sistem tersebut kemudian dimodelkan pada MATLAB Simulink untuk mensimulasikan kinerja dari setiap komponen dan sistem pada Standard Test Condition (STC dari modul PV. Pada keadaan STC, daya 3 fasa maksimum yang dapat dihasilkan adalah 1,716 MW atau 68,54% dari daya DC maksimum sebesar 2,5 MWp. Sistem dapat menghasilkan tegangan fasa-fasa keluaran sebesar 20 kV dengan Total Harmonic Distortion (THD di bawah 5%. Kata kunci: Pusat Listrik Tenaga Surya (PLTS, photovoltaic, Cascaded H-Bridge Multilevel Inverter ABSTRACT The application of Multilevel Inverter in a Photovoltaic Solar Power Plant system could eliminate the needs of step-up transformer, which will reduce the system investment cost, simplify the system installation and also eliminate power losses of the transformer. In this paper, an inverter design was proposed with Cascaded H-Bridge Multilevel Inverter topology that is capable of converting low voltage DC power from several PV arrays into 20 kV AC power. The design resulted a 3 phase 27-level inverter where each level in the inverter has its own photovoltaic array, DC-DC boost converter, H-bridge inverter, and the 3 phase output is connected to LCL filter. Each component of the Inverter and the system were then modelled in MATLAB

  16. Application of interleaved flyback micro inverter in a grid connected system

    Science.gov (United States)

    Brindha, R.; Ananthichristy, A.; Poornima, P. U.; Madhana, M.; Ashok Rathish, S.; Ragavi, Selvam

    2018-04-01

    The two control strategies CCM and DCM have various effects on the loss distribution and efficiency and thus were studied for the interleaved flyback micro inverter concentrating on the loss analysis under different load conditions. The dominant losses with heavy load include the conduction loss and the transformer loss in case of the interleaved flyback micro inverter; whereas driving of gate loss, the turn-off loss in the transformer core loss and in the powermosfets are included in the dominant losses with light load. A new hybrid control strategy which has the one-phase DCM and two-phase DCM control reduces the dominant losses in order to improving the efficiency based on the load in wide load range is proposed here.

  17. PV installations, protection and the code

    Energy Technology Data Exchange (ETDEWEB)

    Silecky, L. [Mersen, Toronto, ON (Canada)

    2010-12-15

    This article discussed the need for improved standards in Ontario's solar industry to ensure safety for the systems and also safety for the workers. Photovoltaic cells used in solar arrays can now deliver between 50 vDC to 600 vDC. The workings of such a high voltage photocell must be understood in order to understand its protection needs. Since PVs are semiconductors and susceptible to damage from short circuits and overloads, a fast-acting overcurrent protective device (OCPD) should be used. Combiner boxes are also needed to provide a clean method of safely connecting all the wires that are needed in the system, including surge protection and a means of isolation between the PV array and the inverter. Section 50 of the Canadian Electrical Code outlines the requirements for solar PV systems, but it does not mention the protection of DC circuits, including DC fuse protectors which are manufactured to provide a high degree of protection for the PV array. As the photovoltaic (PV) market continues to grow in Ontario, the PV industry also has a responsibility to ensure it is in compliance with codes and standards related to photovoltaic systems. This author suggested that Article 690 of the National Electric Code (NEC) is a good document to use when determining the requirements for PV systems. 3 figs.

  18. Simulation and performance analysis of 110 kWp grid-connected photovoltaic system for residential building in India: A comparative analysis of various PV technology

    Directory of Open Access Journals (Sweden)

    Akash Kumar Shukla

    2016-11-01

    Full Text Available System simulation is necessary to investigate the feasibility of Solar PV system at a given location. This study is done to evaluate the feasibility of grid connected rooftop solar photovoltaic system for a residential Hostel building at MANIT, Bhopal, India (Latitude: 23° 16′ N, Longitude: 77° 36′ E. The study focuses on the use of Solargis PV Planner software as a tool to analyze the performance a 110 kWp solar photovoltaic rooftop plant and also compares the performances of different PV technologies based on simulated energy yield and performance ratio. Solargis proves to easy, fast, accurate and reliable software tool for the simulation of solar PV system.

  19. Design and development of high performance solar photovoltaic inverter with advanced modulation techniques to improve power quality

    Science.gov (United States)

    Alexander Stonier, Albert

    2017-02-01

    In addition to the focus towards growing demand on electrical energy due to the increase in population, industries, consumer loads, etc., the need for improving the quality of electrical power also needs to be considered. The design and development of solar photovoltaic (PV) inverter with reduced harmonic distortions is proposed. Unlike the conventional solar PV inverters, the proposed inverter provides the advantages of reduced harmonic distortions thereby intend towards the improvement in power quality. This inverter comprises of multiple stages which provides the required 230VRMS, 50 Hz in spite of variations in solar PV due to temperature and irradiance. The reduction of harmonics is governed by applying proper switching sequences required for the inverter switches. The detailed analysis is carried out by employing different switching techniques and observing its performance. With a separate mathematical model for a solar PV, simulations are performed in MATLAB software. To show the advantage of the system proposed, a 3 kWp photovoltaic plant coupled with multilevel inverter is demonstrated in hardware. The novelty resides in the design of a single chip controller which can provide the switching sequence based on the requirement and application. As per the results obtained, the solar-fed multistage inverter improves the quality of power which makes this inverter suitable for both stand-alone and grid-connected systems.

  20. Leakage Current Suppression with A Novel Six-Switch Photovoltaic Grid-Connected Inverter

    DEFF Research Database (Denmark)

    Wei, Baoze; Guo, Xiaoqiang; Guerrero, Josep M.

    2015-01-01

    In order to solve the problem of the leakage current in non-isolated photovoltaic (PV) systems, a novel six-switch topology and control strategy are proposed in this paper. The inductor-bypass strategy solves the common-mode voltage limitation of the conventional six-switch topology in case...... of unmatched inductances. And the stray capacitor voltage of the non-isolated photovoltaic system is free of high frequency ripples. Theoretical analysis and simulation are carried out to verify the proposed topology and its control strategy. Results indicate that the leakage current suppression can...

  1. Leakage Current Suppression with A Novel Six-Switch Photovoltaic Grid-Connected Inverter

    OpenAIRE

    Wei, Baoze; Guo, Xiaoqiang; Guerrero, Josep M.; Savaghebi, Mehdi

    2015-01-01

    In order to solve the problem of the leakage current in non-isolated photovoltaic (PV) systems, a novel six-switch topology and control strategy are proposed in this paper. The inductor-bypass strategy solves the common-mode voltage limitation of the conventional six-switch topology in case of unmatched inductances. And the stray capacitor voltage of the non-isolated photovoltaic system is free of high frequency ripples. Theoretical analysis and simulation are carried out to verify the propos...

  2. Modeling and Analysis of Resonance in LCL-Type Grid-Connected Inverters under Different Control Schemes

    Directory of Open Access Journals (Sweden)

    Yanxue Yu

    2017-01-01

    Full Text Available As a basic building block in power systems, the three-phase voltage-source inverter (VSI connects the distributed energy to the grid. For the inductor-capacitor-inductor (LCL-filter three-phase VSI, according to different current sampling position and different reference frame, there mainly exist four control schemes. Different control schemes present different impedance characteristics in their corresponding determined frequency range. To analyze the existing resonance phenomena due to the variation of grid impedances, the sequence impedance models of LCL-type grid-connected three-phase inverters under different control schemes are presented using the harmonic linearization method. The impedance-based stability analysis approach is then applied to compare the relative stability issues due to the impedance differences at some frequencies and to choose the best control scheme and the better controller parameters regulating method for the LCL-type three-phase VSI. The simulation and experiments both validate the resonance analysis results.

  3. A Novel Frequency Restoring Strategy of Hydro-PV Hybrid Microgrid

    DEFF Research Database (Denmark)

    Wei, Feng; Kai, Sun; Guan, Yajuan

    2014-01-01

    . The existence of frequency steady-state error and the slow active power/frequency dynamic response are inevitable. Therefore, a novel frequency restoring strategy for the hydro-PV hybrid microgrid based on the improved hierarchical control of PV systems is proposed in this paper. The output active power of PV......The conventional PV systems based on the voltage inverters only inject dispatched power to the utility grid when they work at a grid-connected mode in the hydro-PV hybrid microgrid. Due to the droop method employed for load sharing between generators, as well as the enormous inertia of system...... systems is controlled by an extra frequency restoring controller resided in the tertiary control level. The frequency steady-state error is eliminated through regulating and rebalancing the power flow between the hydropower and the PV system. The proposed strategy has verified through simulations...

  4. Transformerless photovoltaic inverters with leakage current and pulsating power elimination

    DEFF Research Database (Denmark)

    Tang, Yi; Yao, Wenli; Wang, H.

    2015-01-01

    This paper presents a transformerless inverter topology, which is capable of simultaneously solving leakage current and pulsating power issues in grid-connected photovoltaic (PV) systems. Without adding any additional components to the system, the leakage current caused by the PV......-to-ground parasitic capacitance can be bypassed by introducing a common mode (CM) conducting path to the inverter. The resulting ground leakage current is therefore well controlled to be below the regulation limit. Moreover, the proposed inverter can also eliminate the well-known double line frequency pulsating power....... The mechanism of leakage current suppression and the closed-loop control of pulsating power decoupling are discussed in the paper in details. A 500 W prototype was also built and tested in the laboratory, and both simulation and experimental results are finally presented to show the excellent performance...

  5. Techno-economical Analysis of Rooftop Grid-connected PV Dairy Farms; Case Study of Urmia University Dairy Farm

    Science.gov (United States)

    Nikbakht, A. M.; Aste, N.; Sarnavi, H. J.; Leonforte, F.

    2017-08-01

    The global trends indicate a growing commitment to renewable energy development because of declining fossil fuels and environmental threats. Moreover, the global demographic growth coupled with rising demands for food has escalated the rate of energy consumption in food section. This study aims to investigate the techno-economic impacts of a grid-connected rooftop PV plan applied for a educational dairy farm in Urmia university, with total estimated annual electrical energy consumption of 18,283 kWh, located at the north west part of Iran. Based on the current feed-in tariff and tremendously low electricity price in agriculture section in Iran, the plants with size ranged from 14.4 to 19.7 kWp (initial investment ranged from 26,000 to 36,000 USD) would be satisfied economically.

  6. Application of MV/LV Transformers with OLTC for Increasing the PV Hosting Capacity Of LV Grids

    DEFF Research Database (Denmark)

    Hashemi Toghroljerdi, Seyedmostafa; Heckmann, Wolfram; Geibel, Dominik

    2015-01-01

    The increased use of grid connected photovoltaic (PV) systems in low voltage (LV) grids also raises concern regarding the effects of these new generation units on the grid operation. Overvoltage in LV grids during high PV generation periods is one of the well-known effects caused by PV systems......) and the reactive power absorption by PV inverters, are investigated using field test results and simulations performed on the mentioned LV grid. The results show that the application of OLTC can effectively increase the PV hosting capacity of the grid......., which potentially can decrease the PV hosting capacity of electric grids. This paper presents the applications of medium voltage to low voltage (MV/LV) transformers with on-load tap changers (OLTCs) to prevent overvoltage in high PV penetration conditions. Autonomous methods for controlling...

  7. Investigation of common-mode voltage and ground leakage current of grid-connected transformerless PV inverter topology

    OpenAIRE

    Raji, Atanda K; Kahn, Mohamed T E

    2015-01-01

    The problems of increasing electricity demand by the unabated population and economy growth can be solved by employing sustainable distributed generation technologies. Convectional primary energy sources such as coal, liquid hydrocarbons' and natural gasses create environmental degradation and energy security problems. Even though the cost of solar energy is zero, the same cannot be said of a solar energy system. The system cost especially the initial capital investment has been hindering the...

  8. Evaluating the approach to reduce the overrun cost of grid connected PV systems for the Spanish electricity sector: Performance analysis of the period 2010–2012

    International Nuclear Information System (INIS)

    Hoz, Jordi de la; Martín, Helena; Ballart, Jordi; Monjo, Lluis

    2014-01-01

    Highlights: • The cost of the Spanish PV promotion policy from 1998 to 2008 is formulated. • The range of scenarios for the cost evolution is determined. • The PV legal measures addressed to reduce the cost are formulated. • The savings range for the Spanish electricity sector has been determined. • The profitability loss of the facilities due to cost containment measures is assessed. - Abstract: A methodology for calculating the overrun cost to the Spanish electricity system caused by the large overshoot of the PV power targets under the RD 661/2007 is here presented. The elements influencing the cost have been identified, which has allowed proposing different scenarios for its possible evolution. Applying the same methodology, the range of savings achievable by the new energy policy developed in 2010–2012 to reduce this cost has been quantified. Inverting the point of view, the profitability reduction that these energy measures might have caused on the PV facilities has been also assessed. The conclusions obtained from the case of four specific facilities may give some insight about the general economic effects on the installations of the 2010–2012 new energy policy, and the consequences for the investors when the inadequacies of the regulatory schemes are tried to be corrected ex-post

  9. Three-Phase Grid-Connected of Photovoltaic Generator Using Nonlinear Control

    DEFF Research Database (Denmark)

    Yahya, A.; El Fadil, H.; Guerrero, Josep M.

    2014-01-01

    This paper proposes a nonlinear control methodology for three phase grid connected of PV generator. It consists of a PV arrays; a voltage source inverter, a grid filter and an electric grid. The controller objectives are threefold: i) ensuring the Maximum power point tracking (MPPT) in the side...... stability analysis and simulation results that the proposed controller meets all the objectives....

  10. Power Quality Experimental Analysis on Rural Home Grid-Connected PV Systems

    Directory of Open Access Journals (Sweden)

    Rita Jorge Cerqueira Pinto

    2015-01-01

    Full Text Available Microgeneration is the small-scale generation of heat or electric power or both, by individuals or buildings to meet their own needs. Recently, microgeneration is being regarded as a means to decentralize the power production of renewable energies, reducing the impacts on the grid caused by unexpected energy demands. Given the increase in microgeneration facilities, determining the quantity of energy produced and the power quality assumes growing importance in low, medium, or high voltage facilities. This paper presents a power quality analysis of two different facilities with photovoltaic generation localized in a rural area of Portugal, describing the voltage and frequency behaviour, the harmonic contents, and the total harmonic distortion. Statistical data are presented regarding the number of voltage events and occurrence of dips and swells in both facilities as a percentage of rated voltage. We conclude that some PV systems can severely affect voltage quality, forcing the grid to work at and even above the maximum voltage standard limit.

  11. Modeling and simulation of a micro grid-connected solar PV system

    Directory of Open Access Journals (Sweden)

    Rameen AbdelHady

    2017-04-01

    Full Text Available In 2012, the Ministry of Electricity and Renewable Energy (MERE; began promoting the system of ‘Feed-in Tariff’ in billing. The introduced system allows the user to generate electricity through solar panels mounted on the roofs of residential buildings and governmental organizations and tied to the grid. To benefit from MERE’s approach, the National Water Research Center (NWRC (Qanatir, Egypt set up a pilot rooftop 91 kW PV system. All the generated electricity is fed into the 220 V, 50 Hz low voltage grid serving NWRC premises. In this manuscript a MATLAB Simulink model is constructed mimicking a detailed representation of the system tied either to the local low voltage grid or to the national high voltage grid. The aim of such modeling effort is to provide early evaluation of the system performance. The economical savings of both scenarios are compared based on the new billing system. Results show that the current system saves 100 thousand L.E./year, while tying the system to the national grid will save 235.8 thousand L.E./year.

  12. Power Quality Improvement in a Cascaded Multilevel Inverter Interfaced Grid Connected System Using a Modified Inductive–Capacitive–Inductive Filter with Reduced Power Loss and Improved Harmonic Attenuation

    Directory of Open Access Journals (Sweden)

    Meenakshi Jayaraman

    2017-11-01

    Full Text Available Recently, multilevel inverters are more researched due to the advantages they offer over conventional voltage source inverters in grid connected applications. Passive filters are connected at the output of these inverters to produce sinusoidal waveforms with reduced harmonics and to satisfy grid interconnection standard requirements. This work proposes a new passive filter topology for a pulse width modulated five-level cascaded inverter interfaced grid connected system. The proposed passive filter inserts an additional resistance-capacitance branch in parallel to the filter capacitor of the traditional inductive–capacitive–inductive filter in addition to a resistance in series with it to reduce damping power loss. It can attenuate the switching frequency harmonic current components much better than the traditional filter while maintaining the same overall inductance, reduced capacitance and resistance values. The basic parameter design procedure and an approach to discover the parameters of the proposed filter is introduced. Further, a novel methodology using Particle Swarm Optimization (PSO is recommended to guarantee minimum damping loss while ensuring reduced peak during resonance. In addition, PSO algorithm is newly employed in this work to maximize harmonic attenuation in and around the switching frequency on the premise of allowable values of filter inductance and capacitance. A comparative discussion considering traditional passive filters and the proposed filter is presented and evaluated through experiments conducted on a 110 V, 1 kW five-level grid connected inverter. The modulation algorithm for the multilevel inverter is implemented using a SPARTAN 6-XC6SLX25 Field Programmable Gate Array (FPGA processor. The analysis shows that the proposed filter not only provides decreased damping power loss but also is capable of providing considerable harmonic ripple reduction in the high frequency band, improved output waveforms and lesser

  13. Independent control strategy of two DC-link voltages for separate MPPTs in transformerless photovoltaic systems using neutral-point-clamped inverters

    DEFF Research Database (Denmark)

    Choi, Uimin; Blaabjerg, Frede; Lee, Kyo-Beum

    2014-01-01

    To improve the efficiency of the photovoltaic (PV) system, the centralized topology using three-level inverters are widely used. In this system, PV modules are separately connected to the split DC-links. This causes a decrease of maximum power point tracking (MPPT) efficiency under the partial...... shading condition. This paper proposes an independent control of two DC-link voltages for separate MPPT of each PV module in three-level inverters. The proposed method is simply implemented by adding or subtracting the time-offset to the three-phase turn-on times and modifying the reference voltages...

  14. PSCAD Modules Representing PV Generator

    Energy Technology Data Exchange (ETDEWEB)

    Muljadi, E.; Singh, M.; Gevorgian, V.

    2013-08-01

    Photovoltaic power plants (PVPs) have been growing in size, and the installation time is very short. With the cost of photovoltaic (PV) panels dropping in recent years, it can be predicted that in the next 10 years the contribution of PVPs to the total number of renewable energy power plants will grow significantly. In this project, the National Renewable Energy Laboratory (NREL) developed a dynamic modeling of the modules to be used as building blocks to develop simulation models of single PV arrays, expanded to include Maximum Power Point Tracker (MPPT), expanded to include PV inverter, or expanded to cover an entire PVP. The focus of the investigation and complexity of the simulation determines the components that must be included in the simulation. The development of the PV inverter was covered in detail, including the control diagrams. Both the current-regulated voltage source inverter and the current-regulated current source inverter were developed in PSCAD. Various operations of the PV inverters were simulated under normal and abnormal conditions. Symmetrical and unsymmetrical faults were simulated, presented, and discussed. Both the three-phase analysis and the symmetrical component analysis were included to clarify the understanding of unsymmetrical faults. The dynamic model validation was based on the testing data provided by SCE. Testing was conducted at SCE with the focus on the grid interface behavior of the PV inverter under different faults and disturbances. The dynamic model validation covers both the symmetrical and unsymmetrical faults.

  15. Estimating the Technical Potential of Grid-Connected PV Systems in Indonesia : A Comparison of a Method Based on Open Access Data with a Method Based on GIS

    NARCIS (Netherlands)

    Kunaifi, Kunaifi; Reinders, Angelina H.M.E.; Smets, Arno

    2017-01-01

    In this paper, we compare two methods for estimating the technical potential of grid-connected PV systems in Indonesia. One was a method developed by Veldhuis and Renders [1] and the other is a new method using Geographic Information System (GIS) and multi-criteria decision making (MCDM). The first

  16. Resonance Damping and Parameter Design Method for LCL-LC Filter Interfaced Grid-Connected Photovoltaic Inverters

    DEFF Research Database (Denmark)

    Li, Zipeng; Jiang, Aiting; Shen, Pan

    2016-01-01

    , this paper presents a systematic design method for the LCL-LC filtered grid-connected photovoltaic (PV) system. With this method, controller parameters and the active damping feedback coefficient are easily obtained by specifying the system stability and dynamic performance indices, and it is more convenient......-frequency harmonics attenuation ability, but the resonant problem affects the system stability remarkably. In this paper, active damping based on the capacitor voltage feedback is proposed using the concept of the equivalent virtual impedance in parallel with the capacitor. With the consideration of system delay...... to optimize the system performance according to the predefined satisfactory region. Finally, the simulation results are presented to validate the proposed design method and control scheme....

  17. Passivity Enhancement in RES Based Power Plant with Paralleled Grid-Connected Inverters

    DEFF Research Database (Denmark)

    Bai, Haofeng; Wang, Xiongfei; Blaabjerg, Frede

    2016-01-01

    Harmonic instability is threatening the operation of power plants with multiple grid connected converters in parallel. To analyze and improve the stability of the grid connected converters, the passivity of the output admittance converters is first analyzed in this paper. It is shown that the non-passivity...

  18. Global Harmonic Current Rejection of Nonlinear Backstepping Control with Multivariable Adaptive Internal Model Principle for Grid-Connected Inverter under Distorted Grid Voltage

    Directory of Open Access Journals (Sweden)

    Yang Yu

    2013-01-01

    Full Text Available Based on a brief review on current harmonics generation mechanism for grid-connected inverter under distorted grid voltage, the harmonic disturbances and uncertain items are immersed into the original state-space differential equation of grid-connected inverter. A new algorithm of global current harmonic rejection based on nonlinear backstepping control with multivariable internal model principle is proposed for grid-connected inverter with exogenous disturbances and uncertainties. A type of multivariable internal model for a class of nonlinear harmonic disturbances is constructed. Based on application of backstepping control law of the nominal system, a multivariable adaptive state feedback controller combined with multivariable internal model and adaptive control law is designed to guarantee the closed-loop system globally uniformly bounded, which is proved by a constructed Lyapunov function. The presented algorithm extends rejection of nonlinear single-input systems to multivariable globally defined normal form, the correctness and effectiveness of which are verified by the simulation results.

  19. The PWM strategies of grid-connected distributed generation active NPC inverters

    DEFF Research Database (Denmark)

    Ma, Lin; Xinmin, Jin; Kerekes, Tamas

    2009-01-01

    The Neutral Point Clamped topology due to high efficiency, low leakage current and EMI, its integration is widely used in the distributed generation (DG) systems. However the main disadvantage of the NPC inverter is given by an unequal distribution of the losses in the semiconductor devices, which...... leads to an unequal distribution of temperature. By using the Active NPC topology, the power losses distribution problem is alleviated. The modulation strategy is a key issue for losses distribution in this topology. In this paper two known strategies are discussed and a new proposed PWM strategy......, namely the Adjustable Losses Distribution (ALD) PWM strategy is proposed for better losses distribution in the Active NPC (ANPC) topology. Simulations using Simulink and the PLECS toolbox have been done for evaluating efficiency of different NPC topologies and some experimental results are presented...

  20. Stability analysis and active damping for LLCL-filter based grid-connected inverters

    DEFF Research Database (Denmark)

    Huang, Min; Blaabjerg, Frede; Loh, Poh Chiang

    2014-01-01

    A higher order passive power filter (LLCL-filter) for the grid-tied inverter is becoming attractive for the industrial applications due to the possibility to reduce the cost of the copper and the magnetic material. To avoid the well-known stability problems of the LLCL-filter it is requested to use...... either passive or active damping methods. This paper analyzes the stability when damping is required and when damping is not necessary considering sampling and transport delay. Basic LLCL resonance damping properties of different feedback states are also studied. Then an active damping method which...... is using the capacitor current feedback for LLCL-filter is introduced. Based on this method, a design procedure for the control method is given. Last, both simulation and experimental results are provided to validate the theoretical analysis of this paper....

  1. Highly Reliable Transformerless Photovoltaic Inverters With Leakage Current and Pulsating Power Elimination

    DEFF Research Database (Denmark)

    Tang, Yi; Yao, Wenli; Loh, Poh Chiang

    2016-01-01

    This paper presents a transformerless inverter topology, which is capable of simultaneously solving leakage current and pulsating power issues in grid-connected photovoltaic (PV) systems. Without adding any additional components to the system, the leakage current caused by the PV-to-ground parasi......This paper presents a transformerless inverter topology, which is capable of simultaneously solving leakage current and pulsating power issues in grid-connected photovoltaic (PV) systems. Without adding any additional components to the system, the leakage current caused by the PV......-to-ground parasitic capacitance can be bypassed by introducing a common-mode (CM) conducting path to the inverter. The resulting ground leakage current is therefore well controlled to be below the regulation limit. Furthermore, the proposed inverter can also eliminate the well-known double-line-frequency pulsating...... power that is inherent in single-phase PV systems. By properly injecting CM voltages to the output filter capacitors, the pulsating power can be decoupled from the dc-link. Therefore, it is possible to use long-lifetime film capacitors instead of electrolytic capacitors to improve the reliability...

  2. Mathematic model of three-phase induction machine connected to advanced inverter for traction system for electric trolley

    Directory of Open Access Journals (Sweden)

    LIVIU S. BOCÎI

    2013-06-01

    Full Text Available This paper establishes a mathematical model of induction machine connected to a frequency inverter necessary to adjust the electric motor drive. The mathematical model based on the Park's theory allows the analysis of the whole spectrum (electric car – frequency inverter to drive the electric trolley bus made on ASTRA Bus Arad (Romania. To remove higher order harmonics, the PWM waveform of supply voltage is used, set in the general case. Operating characteristics of electric motor drive are set to sub-nominal frequency (f Bele 2007.Este documento estabelece um modelo matemático de máquina de indução conectado a um inversor de frequência necessário para ajustar o motor de acionamento elétrico. O modelo matemático baseado na Teoria de Park permite a análise de todo o espectro (carro elétrico com inversor de frequência para dirigir o ônibus elétrico feito em ASTRA Bus Arad (Romênia. Para remover harmônicas de ordem mais alta, a forma de onda da tensão de alimentação PWM é utilizado, definido no caso geral. Características de funcionamento do motor de acionamento elétrico são definidas para frequência sub-nominal (f

  3. Development of an economical model to determine an appropriate feed-in tariff for grid-connected solar PV electricity in all states of Australia

    International Nuclear Information System (INIS)

    Zahedi, A.

    2009-01-01

    Australia is a country with a vast amount of natural resources including sun and wind. Australia lies between latitude of 10-45 S and longitude of 112-152 E, with a daily solar exposure of between less than 3 MJ/(m 2 day) in winter and more than 30 MJ/(m 2 day) in summer. Global solar radiation in Australia varies between minimum of 3285 MJ/(m 2 year) in Hobart to 8760 MJ/(m 2 year) in Northern Territory. As a result of this wide range of radiation level there will be a big difference between costs of solar PV electricity in different locations. A study we have recently conducted on the solar PV electricity price in all states of Australia. For this purpose we have developed an economical model and a computer simulation to determine the accurate unit price of grid-connected roof-top solar photovoltaic (PV) electricity in A$/kWh for all state of Australia. The benefit of this computer simulation is that we can accurately determine the most appropriate feed-in tariff of grid-connected solar PV energy system. The main objective of this paper is to present the results of this study. A further objective of this paper is to present the details of the unit price of solar PV electricity in the state of Victoria in each month and then to compare with electricity price from conventional power systems, which is currently applied to this state. The state Victoria is located south of Australia and in terms of sun radiation is second lowest compared with the other Australian states. The computer simulation developed for this study makes it possible to determine the cost of grid-connected solar PV electricity at any location in any country based on availability of average daily solar exposure of each month as well as economical factors of the country. (author)

  4. The performance of Dutch photovoltaic inverters in areas with low grid voltage. A preliminary study

    International Nuclear Information System (INIS)

    Van Twisk, J.; Van der Borg, N.J.C.M.; Groeman, J.F.

    2000-08-01

    An important component of grid-connected photovoltaic (PV) systems is the inverter. The inverter must be suitable for the expected characteristics of the input of the photovoltaic panels and for the expected characteristics of the output of the electricity network. The characteristics of the electric grid in potential markets for Dutch inverter manufacturers can differ from the characteristics of Dutch electric grids. A preliminary study has been carried out to determine the characteristics of relevant power distribution systems and the expected effects of those networks on PV-inverters. It is concluded that the following characteristics need further study: voltage level (nominal voltage and long-lasting deviations of that level); transient overvoltages, harmonic components in the voltage, and direct current component. 5 refs

  5. Seismic and Power Generation Performance of U-Shaped Steel Connected PV-Shear Wall under Lateral Cyclic Loading

    OpenAIRE

    Zhang, Hongmei; Dong, Jinzhi; Duan, Yuanfeng; Lu, Xilin; Peng, Jinqing

    2014-01-01

    BIPV is now widely used in office and residential buildings, but its seismic performance still remained vague especially when the photovoltaic (PV) modules are installed on high-rise building facades. A new form of reinforced concrete shear wall integrated with photovoltaic module is proposed in this paper, aiming to apply PV module to the facades of high-rise buildings. In this new form, the PV module is integrated with the reinforced concrete wall by U-shaped steel connectors through embedd...

  6. Islanding detection technique using wavelet energy in grid-connected PV system

    Science.gov (United States)

    Kim, Il Song

    2016-08-01

    This paper proposes a new islanding detection method using wavelet energy in a grid-connected photovoltaic system. The method detects spectral changes in the higher-frequency components of the point of common coupling voltage and obtains wavelet coefficients by multilevel wavelet analysis. The autocorrelation of the wavelet coefficients can clearly identify islanding detection, even in the variations of the grid voltage harmonics during normal operating conditions. The advantage of the proposed method is that it can detect islanding condition the conventional under voltage/over voltage/under frequency/over frequency methods fail to detect. The theoretical method to obtain wavelet energies is evolved and verified by the experimental result.

  7. Mitigation of grid-current distortion for LCL-filtered grid-connected voltage-source inverter with inverter-side current control

    DEFF Research Database (Denmark)

    Xin, Zhen; Mattavelli, Paolo; Yao, WenLi

    2017-01-01

    Due to the low inductance of an LCL-filter, the grid current generated by an LCL-filtered Voltage Source Inverter (VSI) is sensitive to low-order grid-voltage harmonics. This issue is especially tough for the control system with Inverter Current Feedback (ICF), because the grid-current harmonics...... can freely flow into the filter capacitor without control. To cope with this issue, this paper develops an approach for the ICF control system to suppress the grid-current harmonics without adding extra sensors. The proposed method applies harmonic controllers and feedforward scheme simultaneously...

  8. Development of a low cost integrated 15 kW A.C. solar tracking sub-array for grid connected PV power system applications

    Science.gov (United States)

    Stern, M.; West, R.; Fourer, G.; Whalen, W.; Van Loo, M.; Duran, G.

    1997-02-01

    Utility Power Group has achieved a significant reduction in the installed cost of grid-connected PV systems. The two part technical approach focused on 1) The utilization of a large area factory assembled PV panel, and 2) The integration and packaging of all sub-array power conversion and control functions within a single factory produced enclosure. Eight engineering prototype 15kW ac single axis solar tracking sub-arrays were designed, fabricated, and installed at the Sacramento Municipal Utility District's Hedge Substation site in 1996 and are being evaluated for performance and reliability. A number of design enhancements will be implemented in 1997 and demonstrated by the field deployment and operation of over twenty advanced sub-array PV power systems.

  9. The Recent Change in the Italian Policies for Photovoltaics: Effects on the Energy Demand Coverage of Grid-Connected PV Systems Installed in Urban Contexts

    Directory of Open Access Journals (Sweden)

    Aldo Orioli

    2016-11-01

    Full Text Available In July 2013, the Italian photovoltaic (PV support policies changed the feed-in tariff (FIT mechanism and turned to a tax credits program, which is currently in force. The aim of this paper is to investigate how such a radical change has influenced the electricity demand coverage of the PV systems installed in urban contexts. A methodology, which connects the economic assessment to a detailed architectural and energy suitability analysis, was applied to some case studies to analyse the relationships between the physical parameters related to multi-storey buildings (roof shapes, number of floors and area of flats and the most relevant economic and financial features affecting the viability of rooftop PV systems. The study, which considers only the electricity produced by the PV systems that are economically profitable, highlighted that the tax credits scheme is even more effective in covering the electrical consumption of densely urbanised Italian city districts. The results, which are significantly influenced by the latitude of the analysed districts, underline the opportunity for governments to adopt PV promoting policies that are more sensitive to the amount of solar energy available in the different regions of their national territory.

  10. Benchmarking of Phase Locked Loop based Synchronization Techniques for Grid-Connected Inverter Systems

    DEFF Research Database (Denmark)

    Yang, Yongheng; Hadjidemetriou, Lenos; Blaabjerg, Frede

    2015-01-01

    Grid-connected renewables are increasingly developed in recent years, e.g. wind turbine systems and photovoltaic systems. Synchronization of the injected current with the grid is mandatory. However, grid disturbances like voltage sags, harmonics, and frequency deviations may occur during operatio...

  11. Novel concept of a PV power generation system adding the function of shunt active filter

    Energy Technology Data Exchange (ETDEWEB)

    Park, Y.G.; Park, M.; Yu, I.K. [Changwon National Univ., Changwon City (Korea, Republic of). Dept. of Electrical Engineering

    2005-07-01

    A new photovoltaics (PV) power generation system that used an active filter (AF) function was proposed. The AF was installed to condition reactive power and harmonic compensation as well as flicker and voltage regulation. A maximum point power tracking (MPPT) control system was used to stabilize the voltage source inverter (VSI) output current. A general dq transformation was used to compensate the negative components and the harmonics component. The output terminal of the PV array was connected to a smoothing capacitor interfacing the PV-AF inverter. A voltage source PWM converter was controlled with feedback loops of the output current of the inverter. Optimal values of the power inverter gains and filter constants were tuned to obtain responses. The PV system was simulated using real weather conditions. Results of the study demonstrated the stability and effectiveness of the proposed system. It was concluded that the PV-AF can also be used to provide harmonic damping throughout power distribution systems. 12 refs., 3 tabs., 9 figs.

  12. A Systematic Controller Design for a Grid-Connected Inverter with LCL Filter Using a Discrete-Time Integral State Feedback Control and State Observer

    Directory of Open Access Journals (Sweden)

    Seung-Jin Yoon

    2018-02-01

    Full Text Available Inductive-capacitive-inductive (LCL-type filters are currently preferred as a replacement for L-type filters in distributed generation (DG power systems, due to their superior harmonic attenuation capability. However, the third-order dynamics introduced by LCL filters pose a challenge to design a satisfactory controller for such a system. Conventionally, an LCL-filtered grid-connected inverter can be effectively controlled by using a full-state feedback control. However, this control approach requires the measurement of all system state variables, which brings about more complexity for the inverter system. To address this issue, this paper presents a systematic procedure to design an observer-based integral state feedback control for a LCL-filtered grid-connected inverter in the discrete-time domain. The proposed control scheme consists of an integral state feedback controller and a full-state observer which uses the control input, grid-side currents, and grid voltages to predict all the system state variables. Therefore, only the grid-side current sensors and grid voltage sensors are required to implement the proposed control scheme. Due to the discrete-time integrator incorporated in the state feedback controller, the proposed control scheme ensures both the reference tracking and disturbance rejection performance of the inverter system in a practical and simple way. As a result, superior control performance can be achieved by using the reduced number of sensors, which significantly reduces the cost and complexity of the LCL-filtered grid-connected inverter system in DG applications. To verify the practical usefulness of the proposed control scheme, a 2 kW three-phase prototype grid-connected inverter has been constructed, and the proposed control system has been implemented based on 32-bit floating-point digital signal processor (DSP TMS320F28335. The effectiveness of the proposed scheme is demonstrated through the comprehensive simulation

  13. Design and economical analysis of hybrid PV-wind systems connected to the grid for the intermittent production of hydrogen

    International Nuclear Information System (INIS)

    Dufo-Lopez, Rodolfo; Bernal-Agustin, Jose L.; Mendoza, Franklin

    2009-01-01

    In this paper, several designs of hybrid PV-wind (photovoltaic-wind) systems connected to the electrical grid, including the intermittent production of hydrogen, are shown. The objective considered in the design is economical to maximise the net present value (NPV) of the system. A control strategy has been applied so that hydrogen is only produced by the electrolyser when there is an excess of electrical energy that cannot be exported to the grid (intermittent production of hydrogen). Several optimisation studies based on different scenarios have been carried out. After studying the results - for systems with which the produced hydrogen would be sold for external consumption - it can be stated that the selling price of hydrogen should be about 10 Euro /kg in areas with strong wind, in order to get economically viable systems. For the hydrogen-producing systems in which hydrogen is produced when there is an excess of electricity and then stored and later used in a fuel cell to produce electricity to be sold to the grid, even in areas with high wind speed rate, the price of electrical energy produced by the fuel cell should be very high for the system to be profitable.

  14. Generalized coupling resonance modeling, analysis, and active damping of multi-parallel inverters in microgrid operating in grid-connected mode

    DEFF Research Database (Denmark)

    Chen, Zhiyong; Chen, Yandong; Guerrero, Josep M.

    2016-01-01

    This paper firstly presents an equivalent coupling circuit modeling of multi-parallel inverters in microgrid operating in grid-connected mode. By using the model, the coupling resonance phenomena are explicitly investigated through the mathematical approach, and the intrinsic and extrinsic...

  15. A Unified Current Loop Tuning Approach for Grid-Connected Photovoltaic Inverters

    Directory of Open Access Journals (Sweden)

    Weiyi Zhang

    2016-09-01

    Full Text Available High level penetration of renewable energy sources has reshaped modern electrical grids. For the future grid, distributed renewable power generation plants can be integrated in a larger scale. Control of grid-connected converters is required to achieve fast power reference tracking and further to present grid-supporting and fault ride-through performance. Among all of the aspects for converter control, the inner current loop for grid-connected converters characterizes the system performance considerably. This paper proposes a unified current loop tuning approach for grid-connected converters that is generally applicable in different cases. A direct discrete-time domain tuning procedure is used, and particularly, the selection of the phase margin and crossover frequency is analyzed, which acts as the main difference compared with the existing studies. As a general method, the approximation in the modeling of the controller and grid filter is avoided. The effectiveness of the tuning approach is validated in both simulation and experimental results with respect to power reference tracking, frequency and voltage supporting.

  16. Direct-current vector control of three-phase grid-connected rectifier-inverter

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shuhui; Haskew, Timothy A.; Hong, Yang-Ki; Xu, Ling [Department of Electrical and Computer Engineering, University of Alabama, Tuscaloosa, AL 35475 (United States)

    2011-02-15

    The three-phase grid-connected converter is widely used in renewable and electric power system applications. Traditionally, control of the three-phase grid-connected converter is based on the standard decoupled d-q vector control mechanism. Nevertheless, the study of this paper shows that there is a limitation in the conventional standard vector control method. Some of the limitations have also been found recently by other researchers. To overcome the shortage of the conventional vector control technique, this paper proposes a new direct-current d-q vector control mechanism in a nested-loop control structure, based on which an optimal control strategy is developed in a nonlinear programming formulation. The behaviors of both the conventional and proposed control methods are compared and evaluated in simulation and laboratory hardware experiment environments, both of which demonstrates that the proposed approach is effective for grid-connected power converter control in a wide system conditions while the conventional standard vector control approach may behave improperly especially when the converter operates beyond its PWM saturation limit. (author)

  17. EXPERIMENTAL STUDY AND PERFORMANCE OF SOLAR ENERGY SYSTEM WITH GRID CONNECTED POWER SUPPLY

    OpenAIRE

    Pradeep Bharti; Dr. A.K.Sharma

    2017-01-01

    In this paper , we are analyzed about the solar power with grid connection using of various component such as PV Cells battery inverter, and grid power connection , in this way we are connected the grid power and solar power , after that finally we are analyzed the power quality of output with the help of various devices.

  18. Grid-connected photovoltaic systems for Malaysian residential sector: Effects of component costs, feed-in tariffs, and carbon taxes

    International Nuclear Information System (INIS)

    Lau, K.Y.; Muhamad, N.A.; Arief, Y.Z.; Tan, C.W.; Yatim, A.H.M.

    2016-01-01

    Blessed with abundant solar radiation, Malaysia has a huge potential for grid-connected PV (photovoltaic) installations, particularly for its fast-growing residential sector. Nevertheless, Malaysia's PV installation capacity is relatively small compared with the global PV capacity. Significantly, the pricing mechanisms for grid-connected PV projects need to be appropriately assessed to build up the public's confidence to invest in PV projects. In this paper, we analyze the effects of component costs, FiTs (feed-in tariffs), and carbon taxes on grid-connected PV systems in Malaysian residential sector using the HOMER (Hybrid Optimization of Multiple Energy Resources) software. Results demonstrate that the implementation of grid-connected PV systems is highly feasible with PV array costs of $ 1120/kW or lower. For higher PV array costs up to $ 2320/kW, introducing an FiT rate three times higher ($ 0.30/kWh) than the grid tariff for a 100 kW grid sale capacity will, NPC-wise, prioritize grid-connected PV systems over the utility grid. By implementing the FiT ($ 0.50/kWh) and the carbon tax ($ 36/metric ton) schemes simultaneously, grid-connected PV systems will remain as the optimal systems even for costly PV arrays (up to $ 4000/kW). The findings are of paramount importance as far as PV pricing variability is concerned. - Highlights: • Grid-connected PV for Malaysian residential sector has been analyzed using HOMER. • Component costs, feed-in tariffs, and carbon taxes affect optimal system types. • Grid-connected PV projects are feasible for low PV array costs ($ 1120/kW or lower). • For higher PV array and inverter costs, feed-in tariffs should be implemented. • Combining feed-in tariffs with carbon taxes are effective for further lowering NPCs.

  19. New control strategy for grid connecting of wind turbine inverter without converter reactor

    DEFF Research Database (Denmark)

    Rasmussen, Tonny Wederberg; Sørensen, Kasper B.; Bjørneboe, Daniel

    2013-01-01

    Wind turbines and the belonging converters increase in size and price. A reduction in the number of main components is desirable while it reduces need of space, investments and increases the efficiency. A wind turbine contains both a converter reactor and a step up transformer. The paper presents...... theory and laboratory measurements for a new control strategy which make it possibly to connect a wind turbine converter to the utility grid without using the converter reactor or make measurements at the high voltage side of the transformer. The capability to control the DC voltage and reactive power...

  20. Study of LCL filter performance for inverter fed grid connected system

    Science.gov (United States)

    Thamizh Thentral, T. M.; Geetha, A.; Subramani, C.

    2018-04-01

    The abandoned use of power electronic converters in the application of grid connected system paves a way for critical injected harmonics. Hence the use of filter becomes a significant play among the present scenario. Higher order passive filter is mostly preferred in this application because of its reduced cost and size. This paper focuses on the design of LCL filter for the reduction of injected harmonics. The reason behind choosing LCL filter is inductor sizing and good ripple component attenuation over the other conventional filters. This work is simulated in MATLAB platform and the results are prominent to the objectives mentioned above. Also, the simulation results are verified with the implemented hardware model.

  1. Nonlinear adaptive control of grid-connected three-phase inverters for renewable energy applications

    Science.gov (United States)

    Mahdian-Dehkordi, N.; Namvar, M.; Karimi, H.; Piya, P.; Karimi-Ghartemani, M.

    2017-01-01

    Distributed generation (DG) units are often interfaced to the main grid using power electronic converters including voltage-source converters (VSCs). A VSC offers dc/ac power conversion, high controllability, and fast dynamic response. Because of nonlinearities, uncertainties, and system parameters' changes involved in the nature of a grid-connected renewable DG system, conventional linear control methods cannot completely and efficiently address all control objectives. In this paper, a nonlinear adaptive control scheme based on adaptive backstepping strategy is presented to control the operation of a grid-connected renewable DG unit. As compared to the popular vector control technique, the proposed controller offers smoother transient responses, and lower level of current distortions. The Lyapunov approach is used to establish global asymptotic stability of the proposed control system. Linearisation technique is employed to develop guidelines for parameters tuning of the controller. Extensive time-domain digital simulations are performed and presented to verify the performance of the proposed controller when employed in a VSC to control the operation of a two-stage DG unit and also that of a single-stage solar photovoltaic system. Desirable and superior performance of the proposed controller is observed.

  2. Abc-frame complex-coefficient filter and controller based current harmonic elimination strategy for three-phase grid connected inverter

    DEFF Research Database (Denmark)

    Guo, Xiaoqiang; Guerrero, Josep M.

    2016-01-01

    Current quality is one of the most important issues for operating three-phase grid-connected inverter in distributed generation systems. In practice, the grid current quality is degraded in case of non-ideal utility voltage. A new control strategy is proposed for the three-phase gridconnected...... inverter. Different from the traditional method, our proposal utilizes the unique abc-frame complex-coefficient filter and controller to achieve the balanced, sinusoidal grid current. The main feature of the proposed method is simple and easy to implement without any frame transformation. The theoretical...

  3. A Novel Supervisory Control Algorithm to Improve the Performance of a Real-Time PV Power-Hardware-In-Loop Simulator with Non-RTDS

    Directory of Open Access Journals (Sweden)

    Dae-Jin Kim

    2017-10-01

    Full Text Available A programmable direct current (DC power supply with Real-time Digital Simulator (RTDS-based photovoltaic (PV Power Hardware-In-the-Loop (PHIL simulators has been used to improve the control algorithm and reliability of a PV inverter. This paper proposes a supervisory control algorithm for a PV PHIL simulator with a non-RTDS device that is an alternative solution to a high-cost PHIL simulator. However, when such a simulator with the conventional algorithm which is used in an RTDS is connected to a PV inverter, the output is in the transient state and it makes it impossible to evaluate the performance of the PV inverter. Therefore, the proposed algorithm controls the voltage and current target values according to constant voltage (CV and constant current (CC modes to overcome the limitation of the Computing Unit and DC power supply, and it also uses a multi-rate system to account for the characteristics of each component of the simulator. A mathematical model of a PV system, programmable DC power supply, isolated DC measurement device, and Computing Unit are integrated to form a real-time processing simulator. Performance tests are carried out with a commercial PV inverter and prove the superiority of this proposed algorithm against the conventional algorithm.

  4. Techniques for the optimal design of photovoltaic inverters interconnected with the electric grid

    DEFF Research Database (Denmark)

    Koutroulis, Eftichios; Blaabjerg, Frede

    2011-01-01

    the Genetic Algorithm-based optimization procedure is the PV inverter Levelized Cost Of the Electricity generated (LCOE). The proposed method has been applied for the optimal design of PV inverters installed at various sites in Europe. The simulation results indicate that the optimal values of the PV inverter...

  5. PV ready roofing systems

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    The integration of PV technology into roofs of houses has become very popular in the United States, Japan, Germany and The Netherlands. There could be a considerable market in the UK for these systems, given the large number of houses that are projected to be built in the next 10 years, and taking account of increased awareness of energy issues. A significant proportion of the market share of annual installed PV is for solar PV systems installed into homes (currently 15%), this is expected to rise to 23% (900MW) by 2010. The grid connected roof and building mounted facade systems represent the fastest growing market for PV systems in Europe. In conclusion, therefore, innovative approached for fixing PV technology onto roofs have been identified for both domestic roofs and for the commercial sector. With reference to production methodologies within the roofing industry, both approaches should be capable of being designed with PV-ready connections suitable for fixing PV modules at a later date. This will help overcome the key barriers of cost of installation, skills required and the lack of retrofit potential. Based on the results of this project, Sustainable Energy together with PV Systems are keen to take forward the full research and development of PV-ready systems for both the domestic and commercial sectors.

  6. Asymmetrical Grid Fault Ride-Through Strategy of Three-phase Grid-connected Inverter Considering Network Impedance Impact in Low Voltage Grid

    DEFF Research Database (Denmark)

    Guo, Xiaoqiang; Zhang, Xue; Wang, Baocheng

    2014-01-01

    This letter presents a new control strategy of threephase grid-connected inverter for the positive sequence voltage recovery and negative sequence voltage reduction under asymmetrical grid faults. Unlike the conventional control strategy based on an assumption that the network impedance is mainly...... of the proposed solution for the flexible voltage support in a low-voltage grid, where thenetwork impedance is mainly resistive.......This letter presents a new control strategy of threephase grid-connected inverter for the positive sequence voltage recovery and negative sequence voltage reduction under asymmetrical grid faults. Unlike the conventional control strategy based on an assumption that the network impedance is mainly...... inductive, the proposed control strategy is more flexible and effective by considering the network impedance impact, which is of great importance for the high penetration of grid-connected renewable energy systems into low-voltage grids. The experimental tests are carried out to validate the effectiveness...

  7. PV experience curves for the Netherlands

    International Nuclear Information System (INIS)

    Gerwig, R.

    2005-01-01

    Experience curves are one of several tools used by policy makers to take a look at market development. Numerous curves have been constructed for PV but none specific to the Netherlands. The objective of this report is to take a look at the price development of grid-connected PV systems in the Netherlands using the experience curve theory. After a literature and internet search and attempts to acquire information from PV companies information on 51% of the totally installed capacity was found. Curves for the period 1991-2001 were constructed based on system price, BOS (balance-of-system) price and inverter price. The progress ratio of the locally learning BOS was similar to the globally learning module market. This indicates that the pace of development of the Dutch PV market is similar to the globally followed pace. Improvement of the detail of the data might help to get a better idea of which BOS components have declined most. The similar progress ratio also shows the importance of investing both in module and system research as is the case in the Netherlands

  8. Dynamic response evaluation of sensorless MPPT method for hybrid PV-DFIG wind turbine system

    Directory of Open Access Journals (Sweden)

    Danvu Nguyen

    2016-01-01

    Full Text Available This research proposes a sensorless Maximum Power Point Tracking (MPPT method for a hybrid Photovoltaic-Wind system, which consists of Photovoltaic (PV system and Doubly-Fed Induction Generator (DFIG Wind Turbine. In the hybrid system, the DC/DC converter output of the PV system is directly connected to the DC-link of DFIG’s back-to-back converter. Therefore, the PV inverter and its associated circuit can be removed in this structure. Typically, the PV power is monitored by using PV current sensor and PV voltage sensor for MPPT. In this paper, the powers of converters on grid side and rotor side of DFIG are used to estimate the PV power without the PV current sensor. That can efficiently reduce the cost of the hybrid system. The detailed analysis of the sensorless MPPT method, which includes derived equations and operation response, is also presented in this paper. In addition, an overview of PV-DFIG research in literature is stated to supply comprehensive knowledge of related research.

  9. Grid-Connected Control Strategy of Five-level Inverter Based on Passive E-L Model

    Directory of Open Access Journals (Sweden)

    Tao Li

    2017-10-01

    Full Text Available At present, the research on five-level inverters mainly involves the modulation algorithm and topology, and few articles study the five-level inverter from the control strategy. In this paper, the nonlinear passivity-based control (PBC method is proposed for single-phase uninterruptible power supply inverters. The proposed PBC method is based on an energy shaping and damping injection idea, which is performed to regulate the energy flow of an inverter to a desired level and to assure global asymptotic stability, respectively. Furthermore, this paper presents a control algorithm based on the theory of passivity that gives an inverter in a photovoltaic system additional functions: power factor correction, harmonic currents compensation, and the ability to stabilize the system under varying injection damping. Finally, the effectiveness of the PBC method in terms of both stability and harmonic distortion is verified by the simulation and experiments under resistive and inductive loads.

  10. Distributed Storage Inverter and Legacy Generator Integration Plus Renewables Solution for Microgrids

    Science.gov (United States)

    2015-07-01

    inverter (advantage of short term storage) and enables microgrid upgrade of legacy generator assets (integration of inverter and generator controllers ...today. The storage inverter controls and hardware are also leveraged to provide an islanding inverter ( microgrid compatibility) for renewable...transiently rated inverters, integration with legacy generator controls , and microgrid compatible inverters for PV. Key system design drivers are lowering

  11. Seismic and Power Generation Performance of U-Shaped Steel Connected PV-Shear Wall under Lateral Cyclic Loading

    Directory of Open Access Journals (Sweden)

    Hongmei Zhang

    2014-01-01

    Full Text Available BIPV is now widely used in office and residential buildings, but its seismic performance still remained vague especially when the photovoltaic (PV modules are installed on high-rise building facades. A new form of reinforced concrete shear wall integrated with photovoltaic module is proposed in this paper, aiming to apply PV module to the facades of high-rise buildings. In this new form, the PV module is integrated with the reinforced concrete wall by U-shaped steel connectors through embedded steel plates. The lateral cyclic loading test is executed to investigate the seismic behavior and the electric and thermal performance with different drift angles. The seismic behavior, including failure pattern, lateral force-top displacement relationship, and deformation capacity, was investigated. The power generation and temperature variation on the back of the PV module and both sides of the shear wall were also tested. Two main results are demonstrated through the experiment: (1 the U-shaped steel connectors provide enough deformation capacity for the compatibility of the PV module to the shear wall during the whole cyclic test; (2 the electricity generation capacity is effective and stable during this seismic simulation test.

  12. Look-Ahead Energy Management of a Grid-Connected Residential PV System with Energy Storage under Time-Based Rate Programs

    Directory of Open Access Journals (Sweden)

    Kyeon Hur

    2012-04-01

    Full Text Available This paper presents look-ahead energy management system for a grid-connected residential photovoltaic (PV system with battery under critical peak pricing for electricity, enabling effective and proactive participation of consumers in the Smart Grid’s demand response. In the proposed system, the PV is the primary energy source with the battery for storing (or retrieving excessive (or stored energy to pursue the lowest possible electricity bill but it is grid-tied to secure electric power delivery. Premise energy management scheme with an accurate yet practical load forecasting capability based on a Kalman filter is designed to increase the predictability in controlling the power flows among these power system components and the controllable electric appliances in the premise. The case studies with various operating scenarios demonstrate the validity of the proposed system and significant cost savings through operating the energy management scheme.

  13. A Circulating Current Suppression Method for Parallel Connected Voltage-Source-Inverters (VSI) with Common DC and AC Buses

    DEFF Research Database (Denmark)

    Wei, Baoze; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez

    2016-01-01

    This paper describes a theoretical with experiment study on a control strategy for the parallel operation of threephase voltage source inverters (VSI), to be applied to uninterruptible power systems (UPS). A circulating current suppression strategy for parallel VSIs is proposed in this paper based...... on circulating current control loops used to modify the reference currents by compensating the error currents among parallel inverters. Both of the cross and zero-sequence circulating currents are considered. The proposed method is coordinated together with droop and virtual impedance control. In this paper......, droop control is used to generate the reference voltage of each inverter, and the virtual impedance is used to fix the output impedance of the inverters. In addition, a secondary control is used in order to recover the voltage deviation caused by the virtual impedance. And the auxiliary current control...

  14. Novel Differential Current Control Strategy Based on a Modified Three-Level SVPWM for Two Parallel-Connected Inverters

    DEFF Research Database (Denmark)

    Zorig, Abdelmalik; Barkat, Said; Belkheiri, Mohammed

    2017-01-01

    Recently, parallel inverters have been investigated to provide multilevel characteristics besides their advantage to increase the power system capacity, reliability, and efficiency. However, the issue of differential currents imbalance remains a challenge in parallel inverter operation. The distr......Recently, parallel inverters have been investigated to provide multilevel characteristics besides their advantage to increase the power system capacity, reliability, and efficiency. However, the issue of differential currents imbalance remains a challenge in parallel inverter operation....... The distribution of switching vectors of the resulting multilevel topology has a certain degree of self-differential current balancing properties. Nevertheless, the method alone is not sufficient to maintain balanced differential current in practical applications. This paper proposes a closed-loop differential...... current control method by introducing a control variable adjusting the dwell time of the selected switching vectors and thus maintaining the differential currents balanced without affecting the overall system performance. The control strategy, including distribution of switching sequence, selection...

  15. ¬MPPT Pada Sistem PV Menggunakan Algoritma Firefly dan Modified P&O dengan Konverter Hybrid Cuk terkoneksi ke Grid Satu Phasa di Bawah Kondisi Partial Shaded

    Directory of Open Access Journals (Sweden)

    Dhuhari Chalis Bani

    2017-01-01

    Full Text Available Abstrak— Photovoltaic (PV merupakan sumber energi terbarukan yang paling banyak dijumpai di alam serta merupakn energi alternatif yang sangat pesat perkembangannya. Untuk mengahasilkan daya, sebuah PV dipengaruhi sebuah nilai intensitas cahaya matahari yang mengenainya. Sebuah sistem PV membutuhkan sebuah kontrol yang bertujuan untuk meningkatkan efisien daya PV tersebut. Kontrol ini adalah Maximum Power Point Tracking (MPPT yang dapat mengoptimalkan daya yang dihasilkan oleh PV.  Sebuah PV hanya menghasilkan nilai tegangan yang rendah, untuk itu perlu menggunakan koverter DC-DC step up untuk menaikan rasio tegangan DC tadi. Untuk mengoptimalkan sistem ini, diperlukan sebuah konverter yang efisien dan dapat menghasilkan rasio konversi tegangan yang tinggi. Pada penelitian menggunakan firefly algoritm (FFA dan modified perturb and observe (P&O sebagai MPPT untuk mendapatkan nilai daya optimal pada keluaran PV.  Konverter DC-DC yang digunakan adalah hybrid cuk converter boost mode yang memiliki rasio tegangan yang tinggi. Dari DC-link kemudian masuk ke inverter (VSI yang diinterkoneksi dengan grid menggunakan current control. Hasil analisis simulasi menunjukan bahwa FFA dan P&O mampu menghasilkan daya PV yang optimum dengan riak yang kecil dan konverter hybrid cuk converter boost mode dapat menghasilkan rasio tegangan yang lebih besar dibandingkan konverter cuk biasa.   Kata Kunci — PV, MPPT FFA, MPPT P&O, Hybrid Cuk Converter, DC-Link, Inverter Grid Connected

  16. Comparative Study of Modulation-Based Individual Inverter Techniques for Direct and Inverse by using Star-Connection Induction Motor in Extra Low Voltage Application

    Directory of Open Access Journals (Sweden)

    Ardhia Wishnuprakasa

    2016-12-01

    Full Text Available In this study, the IEEE 519 Standard as a basis benchmarking for voltage (THDV and current (THDI in draft performance. Comparative Study based onthree-techniques of 2-Level Converter (2LC by using a Star-Connection Induction Motor (Y-CIM in ExtraLow Voltage (ELV Configuration.For the detail explanation, a primary inverter as Direct-Inverterby PWMdirect (PWM degreesand asecondary inverter as Inverse-Inverterby PWMinverse(PWM + PI degrees. It tends a modified algorithm,for eachof SPWM in six rules, and FHIPWM in 5th harmonics Injectedin standard modulation as the purpose for the Open-Ends of Pre-Dual Inverter in Decoupled SPWM for twelve rules, and Decoupled FHIPWM in combination of 5th harmonics Injectedin combination of two-standard-modulation. Those techniques are the purpose of two-inverter combination, which namelythe Equal Direct-Inverse (EDI algorithmproduct of prototyping in similarities. The observation is restricted in voltage scope between Simulation by using Power Simulator (PSIMand Application by using Microcontroller ARM STM32F4 Discovery.

  17. Accelerating development of advanced inverters :

    Energy Technology Data Exchange (ETDEWEB)

    Neely, Jason C.; Gonzalez, Sigifredo; Ropp, Michael; Schutz, Dustin

    2013-11-01

    The high penetration of utility interconnected photovoltaic (PV) systems is causing heightened concern over the effect that variable renewable generation will have on the electrical power system (EPS). These concerns have initiated the need to amend the utility interconnection standard to allow advanced inverter control functionalities that provide: (1) reactive power control for voltage support, (2) real power control for frequency support and (3) better tolerance of grid disturbances. These capabilities are aimed at minimizing the negative impact distributed PV systems may have on EPS voltage and frequency. Unfortunately, these advanced control functions may interfere with island detection schemes, and further development of advanced inverter functions requires a study of the effect of advanced functions on the efficacy of antiislanding schemes employed in industry. This report summarizes the analytical, simulation and experimental work to study interactions between advanced inverter functions and anti-islanding schemes being employed in distributed PV systems.

  18. The PV market

    International Nuclear Information System (INIS)

    Hammond, B.

    1992-01-01

    This paper forecasts the photovoltaic (PV) market growth for the 1990s. Ten years of PV history are reviewed and used to establish market trends in terms of average selling price (ASP) and kilowatts shipped by market segment. The market is segmented into indoor consumer, stand-alone, and grid-connected applications. Indoor consumer presently represents a saturated market and is fairly predictable. The stand-alone market (i.e. not connected to the utility grid) is fairly stable and predictable. The utility PV market however is highly dependent on a number of market factors such as the cost of conventional energy the cost of PV systems utility acceptance of PV and regulatory controls. Government and institutional regulations, environmental issues, and OPEC and Middle East politics will have the greatest impact on the cost of conventional fuels. Private and federal investment in PV technology development could have a significant impact on the cost of PV systems. Forecasts are provided through the year 2000 for indoor consumer stand-alone and utility markets

  19. Capacitor Current Feedback-Based Active Resonance Damping Strategies for Digitally-Controlled Inductive-Capacitive-Inductive-Filtered Grid-Connected Inverters

    Directory of Open Access Journals (Sweden)

    Iman Lorzadeh

    2016-08-01

    Full Text Available Inductive-capacitive-inductive (LCL-type line filters are widely used in grid-connected voltage source inverters (VSIs, since they can provide substantially improved attenuation of switching harmonics in currents injected into the grid with lower cost, weight and power losses than their L-type counterparts. However, the inclusion of third order LCL network complicates the current control design regarding the system stability issues because of an inherent resonance peak which appears in the open-loop transfer function of the inverter control system near the control stability boundary. To avoid passive (resistive resonance damping solutions, due to their additional power losses, active damping (AD techniques are often applied with proper control algorithms in order to damp the LCL filter resonance and stabilize the system. Among these techniques, the capacitor current feedback (CCF AD has attracted considerable attention due to its effective damping performance and simple implementation. This paper thus presents a state-of-the-art review of resonance and stability characteristics of CCF-based AD approaches for a digitally-controlled LCL filter-based grid-connected inverter taking into account the effect of computation and pulse width modulation (PWM delays along with a detailed analysis on proper design and implementation.

  20. A Circulating-Current Suppression Method for Parallel-Connected Voltage-Source Inverters With Common DC and AC Buses

    DEFF Research Database (Denmark)

    Wei, Baoze; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez

    2017-01-01

    This paper presents a theoretical study with experimental validation of a circulating-current suppression method for parallel operation of three-phase voltage source inverters (VSI), which may be suitable for modular parallel uninterruptible power supply systems or hybrid AC/DC microgrid applicat......This paper presents a theoretical study with experimental validation of a circulating-current suppression method for parallel operation of three-phase voltage source inverters (VSI), which may be suitable for modular parallel uninterruptible power supply systems or hybrid AC/DC microgrid......, and added into the conventional droop plus virtual impedance control. In the control architecture, the reference voltages of the inverters are generated by the primary control loop which consists of a droop control and a virtual impedance. The secondary control is used to compensate the voltage drop...

  1. Capacitor Current Feedback-Based Active Resonance Damping Strategies for Digitally-Controlled Inductive-Capacitive-Inductive-Filtered Grid-Connected Inverters

    DEFF Research Database (Denmark)

    Lorzadeh, Iman; Askarian Abyaneh, Hossein; Savaghebi, Mehdi

    2016-01-01

    Inductive-capacitive-inductive (LCL)-type line filters are widely used in grid-connected voltage source inverters (VSIs), since they can provide substantially improved attenuation of switching harmonics in currents injected into the grid with lower cost, weight and power losses than their L......-type counterparts. However, the inclusion of third order LCL network complicates the current control design regarding the system stability issues because of an inherent resonance peak which appears in the open-loop transfer function of the inverter control system near the control stability boundary. To avoid...... passive (resistive) resonance damping solutions, due to their additional power losses, active damping (AD) techniques are often applied with proper control algorithms in order to damp the LCL filter resonance and stabilize the system. Among these techniques, the capacitor current feedback (CCF) AD has...

  2. Implementation of grid-connected to/from off-grid transference for micro-grid inverters

    OpenAIRE

    Heredero Peris, Daniel; Chillón Antón, Cristian; Pages Gimenez, Marc; Gross, Gabriel Igor; Montesinos Miracle, Daniel

    2013-01-01

    This paper presents the transfer of a microgrid converter from/to on-grid to/from off-grid when the converter is working in two different modes. In the first transfer presented method, the converter operates as a Current Source Inverter (CSI) when on-grid and as a Voltage Source Inverter (VSI) when off-grid. In the second transfer method, the converter is operated as a VSI both, when operated on-grid and off-grid. The two methods are implemented successfully in a real pla...

  3. Energy matrices evaluation and exergoeconomic analysis of series connected N partially covered (glass to glass PV module) concentrated-photovoltaic thermal collector: At constant flow rate mode

    International Nuclear Information System (INIS)

    Tripathi, Rohit; Tiwari, G.N.; Dwivedi, V.K.

    2017-01-01

    Highlights: • Fluid, other than water has been chosen for achieving higher outlet temperature. • Mass flow rate and number of collector have been optimized. • Three PVT systems have been compared for evaluating annual energy and exergy. • Life cycle cost analysis has been evaluated to obtain exergetic cost. • Proposed PVT systems have been compared on the basis of energy matrices. - Abstract: In present analysis, a comparative study has been carried out to evaluate the annual performances of three systems or cases at constant flow rate, namely: case (i): partially covered (25% PV module) N concentrated photovoltaic thermal collectors connected in series, case (ii): fully covered (100% PV module) N concentrated photovoltaic thermal collectors in series and case (iii): N (0% PV module) convectional compound parabolic concentrator collector connected in series. Comparison for three cases has also been carried out by considering fluid namely: ethylene glycol for higher outlet temperature and better thermal performance which can be applicable for heating and steaming or small industry purpose. The embodied energy, energy matrices, uniform annual cost, exergetic cost and carbon credits are also evaluated for same systems. The energy payback time is found to be 5.58 years and energy production factor is to be 0.17 on energy basis for case (iii) which is maximum. The exergetic cost has computed as 17.85 Rs/kW h for 30 years of life time of the system. It is observed that N conventional compound parabolic concentrator collector [case (iii)] is most suitable for steam cooking or space heating but not self-sustainable to run the dc power motor due to unavailability of electrical power.

  4. Fault Analysis and Detection in Microgrids with High PV Penetration

    Energy Technology Data Exchange (ETDEWEB)

    El Khatib, Mohamed [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hernandez Alvidrez, Javier [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ellis, Abraham [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-05-01

    In this report we focus on analyzing current-controlled PV inverters behaviour under faults in order to develop fault detection schemes for microgrids with high PV penetration. Inverter model suitable for steady state fault studies is presented and the impact of PV inverters on two protection elements is analyzed. The studied protection elements are superimposed quantities based directional element and negative sequence directional element. Additionally, several non-overcurrent fault detection schemes are discussed in this report for microgrids with high PV penetration. A detailed time-domain simulation study is presented to assess the performance of the presented fault detection schemes under different microgrid modes of operation.

  5. Voltage unbalance mitigation in LV networks using three-phase PV systems

    DEFF Research Database (Denmark)

    Garcia Bajo, Cristina; Hashemi Toghroljerdi, Seyedmostafa; Bækhøj Kjær, Søren

    2015-01-01

    In this paper a new method is proposed to mitigate voltage unbalance caused by single-phase solar inverters in low voltage (LV) networks. The method is based on uneven reactive power absorption and injection by three-phase solar inverters. Independent control of each phase is performed to achieve...... this uneven injection. The average values of phase voltages at the connection points of the photovoltaic (PV) inverters are used as the references for the balancing algorithm. Voltage unbalance mitigation is achieved by use of this method in different scenarios with variable three-phase and single......-phase inverters penetration in a realistic LV grid. In addition, the overvoltage is reduced by using this method....

  6. Design and Analysis of Stepped DC Link Hybrid Converter for Solar PV Systems

    Directory of Open Access Journals (Sweden)

    R. Uthirasamy

    2017-09-01

    Full Text Available A structure of single phase DC Link Multilevel H-Bridge Inverter (DCLMLHBI is proposed for symmetrical Photo Voltaic (PV systems. Voltage stress across the inverter switches, Power Spectral Density (PSD, voltage and current harmonics are reduced in the proposed configuration. Compared with conventional 13-level Cascaded Multilevel Inverter (CMLI configuration, the proposed system configuration is structured with less number of series connected power switches and gate drive circuits. None of the passive components are utilized in the proposed inverter configuration, which highlight the significance of the proposed system. The performance parameters are investigated through Phase Opposition Pulse Width Modulation (POD-PWM switching scheme and its results are validated with computer simulation and prototype hardware models.

  7. Optimal Parameter Selection for Support Vector Machine Based on Artificial Bee Colony Algorithm: A Case Study of Grid-Connected PV System Power Prediction

    Directory of Open Access Journals (Sweden)

    Xiang-ming Gao

    2017-01-01

    Full Text Available Predicting the output power of photovoltaic system with nonstationarity and randomness, an output power prediction model for grid-connected PV systems is proposed based on empirical mode decomposition (EMD and support vector machine (SVM optimized with an artificial bee colony (ABC algorithm. First, according to the weather forecast data sets on the prediction date, the time series data of output power on a similar day with 15-minute intervals are built. Second, the time series data of the output power are decomposed into a series of components, including some intrinsic mode components IMFn and a trend component Res, at different scales using EMD. The corresponding SVM prediction model is established for each IMF component and trend component, and the SVM model parameters are optimized with the artificial bee colony algorithm. Finally, the prediction results of each model are reconstructed, and the predicted values of the output power of the grid-connected PV system can be obtained. The prediction model is tested with actual data, and the results show that the power prediction model based on the EMD and ABC-SVM has a faster calculation speed and higher prediction accuracy than do the single SVM prediction model and the EMD-SVM prediction model without optimization.

  8. Optimal Parameter Selection for Support Vector Machine Based on Artificial Bee Colony Algorithm: A Case Study of Grid-Connected PV System Power Prediction.

    Science.gov (United States)

    Gao, Xiang-Ming; Yang, Shi-Feng; Pan, San-Bo

    2017-01-01

    Predicting the output power of photovoltaic system with nonstationarity and randomness, an output power prediction model for grid-connected PV systems is proposed based on empirical mode decomposition (EMD) and support vector machine (SVM) optimized with an artificial bee colony (ABC) algorithm. First, according to the weather forecast data sets on the prediction date, the time series data of output power on a similar day with 15-minute intervals are built. Second, the time series data of the output power are decomposed into a series of components, including some intrinsic mode components IMFn and a trend component Res, at different scales using EMD. The corresponding SVM prediction model is established for each IMF component and trend component, and the SVM model parameters are optimized with the artificial bee colony algorithm. Finally, the prediction results of each model are reconstructed, and the predicted values of the output power of the grid-connected PV system can be obtained. The prediction model is tested with actual data, and the results show that the power prediction model based on the EMD and ABC-SVM has a faster calculation speed and higher prediction accuracy than do the single SVM prediction model and the EMD-SVM prediction model without optimization.

  9. The Influence of phase-locked loop on the stability of single-phase grid-connected inverter

    DEFF Research Database (Denmark)

    Zhang, Chong; Wang, Xiongfei; Blaabjerg, Frede

    2015-01-01

    . Moreover, the Second Order Generalized Integrator PLL (SOGI-PLL) and the inverse Park transformation PLL (Park-PLL) are also modeled. It is found that the quadrature signal generators of SOGI-PLL and Park-PLL play a stabilizing role in grid-inverter interactions, which thus provide promising candidates...

  10. Adaptive Droop Control Applied to Voltage-Source Inverters Operating in Grid-Connected and Islanded Modes

    DEFF Research Database (Denmark)

    Vasquez, J. C.; Guerrero, J. M.; Luna, A.

    2009-01-01

    This paper proposes a novel control for voltagesource inverters with the capability to flexibly operate in gridconnected and islanded modes. The control scheme is based on the droop method, which uses some estimated grid parameters such as the voltage and frequency and the magnitude and angle of ...

  11. Inverter communications using output signal

    Science.gov (United States)

    Chapman, Patrick L.

    2017-02-07

    Technologies for communicating information from an inverter configured for the conversion of direct current (DC) power generated from an alternative source to alternating current (AC) power are disclosed. The technologies include determining information to be transmitted from the inverter over a power line cable connected to the inverter and controlling the operation of an output converter of the inverter as a function of the information to be transmitted to cause the output converter to generate an output waveform having the information modulated thereon.

  12. Remote and Centralized Monitoring of PV Power Plants

    DEFF Research Database (Denmark)

    Kopacz, Csaba; Spataru, Sergiu; Sera, Dezso

    2014-01-01

    the inverters within each PV plant. The monitoring software stores the PV measurements in a data warehouse optimized for managing and data mining large amounts of data, from where it can be later visualized, analyzed and exported. By combining PV production measurements data with I-V curve measurements...

  13. Modeling the frequency response of photovoltaic inverters

    NARCIS (Netherlands)

    Ernauli Christine Aprilia, A.; Cuk, V.; Cobben, J.F.G.; Ribeiro, P.F.; Kling, W.L.

    2012-01-01

    The increased presence of photovoltaic (PV) systems inevitably affects the power quality in the grid. This new reality demands grid power quality studies involving PV inverters. This paper proposes several frequency response models in the form of equivalent circuits. Models are based on laboratory

  14. Stationary Frame Current Control Evaluations for Three-Phase Grid-Connected Inverters with PVR-based Active Damped LCL Filters

    DEFF Research Database (Denmark)

    Han, Yang; Shen, Pan; Guerrero, Josep M.

    2016-01-01

    Grid-connected inverters (GCIs) with LCL output filter have the ability of attenuating high-frequency (HF) switching ripples. However, by using only grid-current control, the system is prone to resonances if it is not properly damped, and the current distortion would be amplified significantly...... method is adopted. Furthermore, the grid voltage feed-forward and multiple PR controllers are integrated in the current loop to mitigate the current distortion introduced by the grid background distortion. Besides, the parameters design guidelines are presented to show the feasibility and effectiveness...

  15. Multiple low frequency dual reference PWM control of a grid connected photovoltaic three phase NPC inverter with DC/DC boost converter

    Directory of Open Access Journals (Sweden)

    Mechouma Rabiaa

    2014-01-01

    Full Text Available In recent years, power demand of industrial applications has increased significantly reaching some megawatts. The use of multilevel converters for applications of medium and high powers is proposed as a solution to drawback semiconductor technology. A multilevel converter not only achieves high power ratings, but also enables the use of renewable energy sources. Renewable energy sources such as photovoltaic can be easily interfaced to a multilevel converter system for a high power application. This paper presents the simulation study in Matlab/Simulink of a grid connected photovoltaic three phase Neutral Point Clamped (NPC inverter with DC/DC boost converter for constant and variable solar radiation.

  16. PV power plants

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-07-01

    Within the international seminar of the Ostbayerisches Technologie-Transfer-Institut e.V. (OTTI) at 11th June, 2012 in Munich (Federal Republic of Germany), the following lectures were held: (1) Technical due diligence (Dietmar Obst); (2) Certification / rating system for large PV plants (Robert Pfatischer); (3) O and M requirements (Lars Rulf); (4) IR photography for large scale systems (Bernhard Weinreich); (5) New market models for PV systems - direct marketing and sales of PV electricity (Martin Schneider); (6) Needs and benefits for plant certification for grid connection and operation (Christoph Luetke-Lengerich); (7) Lare volume module testing / Screening in the field and workshop (Semir Merzoug); (8) Dismantling costs of large scale PV plants (Siegfried Schimpf).

  17. A New Way of Controlling Parallel-Connected Inverters by Using Synchronous-Reference-Frame Virtual Impedance Loop

    DEFF Research Database (Denmark)

    Guan, Yajuan; Guerrero, Josep M.; Zhao, Xin

    2016-01-01

    A novel simple and effective autonomous current-sharing controller for parallel three-phase inverters is proposed in this paper. The proposed controller provides faster response and better accuracy in contrast to the conventional droop control, since this novel approach does not require any active...... or reactive power calculations. Instead, a synchronous-reference-frame (SRF) virtual impedance loop and an SRF-based phase-locked loop are used. Stationary analysis is provided in order to identify the inherent mechanism of the direct and quadrature output currents in relation to the voltage amplitude...... from a setup with three parallel 2.2 kW inverters verify the effectiveness of the proposed control strategy in different scenarios....

  18. Modular inverter system

    Science.gov (United States)

    Ma, Mingyao; Hu, Haibing; Kutkut, Nasser; Batarseh, Issa; Shen, John; , Bkayrat, Raed

    2017-08-01

    A system connected to an AC power grid having an AC phase signal includes an inverter module including a first inverter coupled to a DC voltage, actuated based on the AC phase signal. The first inverter provides a first voltage signal having predetermined harmonic components. A second inverter includes second switch elements coupled to the DC voltage and actuated by a second set of control signals phase delayed with respect to the first control signals. A transformer module has first and second primary windings coupled to the first and second inverters. The transformer module further includes a secondary winding coupled to first primary winding, the second primary winding, and the AC power grid. The secondary winding is configured to provide a secondary output voltage to the AC power grid by combining the first voltage signal and the second voltage signal such that the predetermined harmonic components are substantially cancelled.

  19. Smart Inverter Control and Operation for Distributed Energy Resources

    Science.gov (United States)

    Tazay, Ahmad F.

    The motivation of this research is to carry out the control and operation of smart inverters and voltage source converters (VSC) for distributed energy resources (DERs) such as photovoltaic (PV), battery, and plug-in hybrid electric vehicles (PHEV). The main contribution of the research includes solving a couple of issues for smart grids by controlling and implementing multifunctions of VSC and smart inverter as well as improving the operational scheme of the microgrid. The work is mainly focused on controlling and operating of smart inverter since it promises a new technology for the future microgrid. Two major applications of the smart inverter will be investigated in this work based on the connection modes: microgrid at grid-tied mode and autonomous mode. In grid-tied connection, the smart inverter and VSC are used to integrate DER such as Photovoltaic (PV) and battery to provide suitable power to the system by controlling the supplied real and reactive power. The role of a smart inverter at autonomous mode includes supplying a sufficient voltage and frequency, mitigate abnormal condition of the load as well as equally sharing the total load's power. However, the operational control of the microgrid still has a major issue on the operation of the microgrid. The dissertation is divided into two main sections which are: 1. Low-level control of a single smart Inverter. 2. High-level control of the microgrid. The first part investigates a comprehensive research for a smart inverter and VSC technology at the two major connections of the microgrid. This involves controlling and modeling single smart inverter and VSC to solve specific issues of microgrid as well as improve the operation of the system. The research provides developed features for smart inverter comparing with a conventional voltage sourced converter (VSC). The two main connections for a microgrid have been deeply investigated to analyze a better way to develop and improve the operational procedure of

  20. Hawaiian Electric Advanced Inverter Test Plan - Result Summary

    Energy Technology Data Exchange (ETDEWEB)

    Hoke, Anderson; Nelson, Austin; Prabakar, Kumaraguru; Nagarajan, Adarsh

    2016-10-14

    This presentation is intended to share the results of lab testing of five PV inverters with the Hawaiian Electric Companies and other stakeholders and interested parties. The tests included baseline testing of advanced inverter grid support functions, as well as distribution circuit-level tests to examine the impact of the PV inverters on simulated distribution feeders using power hardware-in-the-loop (PHIL) techniques. hardware-in-the-loop (PHIL) techniques.

  1. A case study of utility PV economics

    International Nuclear Information System (INIS)

    Wenger, H.; Hoff, T.; Osborn, D.E.

    1997-01-01

    This paper presents selected results from a detailed study of grid-connected photovoltaic (PV) applications within the service area of the Sacramento Municipal Utility District. The intent is to better understand the economics and markets for grid-connected PV systems in a utility setting. Research results include: Benefits calculations for utility-owned PV systems at transmission and distribution voltages; How the QuickScreen software package can help utilities investigate the viability of distributed PV; Energy production and capacity credit estimates for fixed and tracking PV systems; Economics and rate impacts of net metering residential PV systems; Market potential estimates for residential rooftop PV systems; and Viability and timing of grid-connected PV commercialization paths

  2. Extended Stable Boundary of LCL-Filtered Grid-Connected Inverter Based on An Improved Grid-Voltage Feedforward Control

    DEFF Research Database (Denmark)

    Lu, Minghui; Xin, Zhen; Wang, Xiongfei

    2016-01-01

    should be designed under one-sixth of sampling frequency. However, the low resonance frequency leads to a comparatively large filter inductance or/and capacitance. To extend the stable boundary to the region above fs/6, this paper proposes a novel voltage feedforward scheme for the LCL-filtered inverter....... Theoretical analysis is then provided to validate its feasibility and stability. Compared to other widely used active damping strategies, no extra sensors are needed because the filter capacitor voltage, which is used for voltage feedforward control, is also sampled for phase-locked loop in this paper...

  3. Interactive smart battery storage for a PV and wind hybrid energy management control based on conservative power theory

    Science.gov (United States)

    Godoy Simões, Marcelo; Davi Curi Busarello, Tiago; Saad Bubshait, Abdullah; Harirchi, Farnaz; Antenor Pomilio, José; Blaabjerg, Frede

    2016-04-01

    This paper presents interactive smart battery-based storage (BBS) for wind generator (WG) and photovoltaic (PV) systems. The BBS is composed of an asymmetric cascaded H-bridge multilevel inverter (ACMI) with staircase modulation. The structure is parallel to the WG and PV systems, allowing the ACMI to have a reduction in power losses compared to the usual solution for storage connected at the DC-link of the converter for WG or PV systems. Moreover, the BBS is embedded with a decision algorithm running real-time energy costs, plus a battery state-of-charge manager and power quality capabilities, making the described system in this paper very interactive, smart and multifunctional. The paper describes how BBS interacts with the WG and PV and how its performance is improved. Experimental results are presented showing the efficacy of this BBS for renewable energy applications.

  4. Data monitoring system for PV solar generators

    International Nuclear Information System (INIS)

    Stoev, M.; Katerski, A.; Williams, A.

    2000-01-01

    The two 1.5 kWp photovoltaic (PV) solar generators are installed and the new PC data monitoring system is developed by applying EC standards for European Solar Test Installation (ESTI). The schematic system diagram of PV generator is presented. The recording parameters for analytical and global monitoring are discussed. The meteorological data from ESTI sensors, temperature sensor and electrical data from inverter and calibrated shunt are stored via analog digital converters (ADC) on a hard disk of data storage PC. Data Logger and Monitor software for automatic data acquisition, treatment and visual distance control of all output PV data from PV solar generator has been created

  5. Actual performance and characteristic of a grid connected photovoltaic power system in the tropics: A short term evaluation

    International Nuclear Information System (INIS)

    Khatib, Tamer; Sopian, Kamaruzzaman; Kazem, Hussein A.

    2013-01-01

    Highlights: • We analyzed an actual performance of grid connected PV system. • We derived accurate models for the system based on the actual performance. • We assist the electricity productively of the proposed system. - Abstract: This paper presents a field operation experience for a grid connected PV system under tropical climate. The system is consisted of a 5 kWp photovoltaic (PV) array and a 6 kW DC/AC inverter. The operation performance data are recorded in order to develop accurate mathematical models for the system as well as to evaluate the productivity of the system. The experiment results show that, the average PV performance (the ratio of the theoretical performance to the actual performance) is 73.12% while the average inverter performance (the ratio of the theoretical inverter efficiency to the actual inverter efficiency) is 98.56%. Moreover, it is found that the daily yield factor of the PV system is 2.51 kW h/kWp day while, the capacity factor is 10.47%. However, it is concluded that the productivity of the system is below the prospected rate and thus, an inspection of the system must be done in order to diagnose the problem of the system’s low productivity. This paper presents worthwhile information for those who are interested in PV system installation in Malaysia and nearby country

  6. Advanced Energy Validated Photovoltaic Inverter Technology at NREL | Energy

    Science.gov (United States)

    Inverter Technology at NREL Advanced Energy Industries-NREL's first partner at the Energy Systems Integration Facility (ESIF)-validated its advanced photovoltaic (PV) inverter technology using the ESIF's computer screen in a laboratory, with power inverter hardware in the background Photo by Dennis Schroeder

  7. Indirect adaptive soft computing based wavelet-embedded control paradigms for WT/PV/SOFC in a grid/charging station connected hybrid power system.

    Directory of Open Access Journals (Sweden)

    Sidra Mumtaz

    Full Text Available This paper focuses on the indirect adaptive tracking control of renewable energy sources in a grid-connected hybrid power system. The renewable energy systems have low efficiency and intermittent nature due to unpredictable meteorological conditions. The domestic load and the conventional charging stations behave in an uncertain manner. To operate the renewable energy sources efficiently for harvesting maximum power, instantaneous nonlinear dynamics should be captured online. A Chebyshev-wavelet embedded NeuroFuzzy indirect adaptive MPPT (maximum power point tracking control paradigm is proposed for variable speed wind turbine-permanent synchronous generator (VSWT-PMSG. A Hermite-wavelet incorporated NeuroFuzzy indirect adaptive MPPT control strategy for photovoltaic (PV system to extract maximum power and indirect adaptive tracking control scheme for Solid Oxide Fuel Cell (SOFC is developed. A comprehensive simulation test-bed for a grid-connected hybrid power system is developed in Matlab/Simulink. The robustness of the suggested indirect adaptive control paradigms are evaluated through simulation results in a grid-connected hybrid power system test-bed by comparison with conventional and intelligent control techniques. The simulation results validate the effectiveness of the proposed control paradigms.

  8. Indirect adaptive soft computing based wavelet-embedded control paradigms for WT/PV/SOFC in a grid/charging station connected hybrid power system.

    Science.gov (United States)

    Mumtaz, Sidra; Khan, Laiq; Ahmed, Saghir; Bader, Rabiah

    2017-01-01

    This paper focuses on the indirect adaptive tracking control of renewable energy sources in a grid-connected hybrid power system. The renewable energy systems have low efficiency and intermittent nature due to unpredictable meteorological conditions. The domestic load and the conventional charging stations behave in an uncertain manner. To operate the renewable energy sources efficiently for harvesting maximum power, instantaneous nonlinear dynamics should be captured online. A Chebyshev-wavelet embedded NeuroFuzzy indirect adaptive MPPT (maximum power point tracking) control paradigm is proposed for variable speed wind turbine-permanent synchronous generator (VSWT-PMSG). A Hermite-wavelet incorporated NeuroFuzzy indirect adaptive MPPT control strategy for photovoltaic (PV) system to extract maximum power and indirect adaptive tracking control scheme for Solid Oxide Fuel Cell (SOFC) is developed. A comprehensive simulation test-bed for a grid-connected hybrid power system is developed in Matlab/Simulink. The robustness of the suggested indirect adaptive control paradigms are evaluated through simulation results in a grid-connected hybrid power system test-bed by comparison with conventional and intelligent control techniques. The simulation results validate the effectiveness of the proposed control paradigms.

  9. Indirect adaptive soft computing based wavelet-embedded control paradigms for WT/PV/SOFC in a grid/charging station connected hybrid power system

    Science.gov (United States)

    Khan, Laiq; Ahmed, Saghir; Bader, Rabiah

    2017-01-01

    This paper focuses on the indirect adaptive tracking control of renewable energy sources in a grid-connected hybrid power system. The renewable energy systems have low efficiency and intermittent nature due to unpredictable meteorological conditions. The domestic load and the conventional charging stations behave in an uncertain manner. To operate the renewable energy sources efficiently for harvesting maximum power, instantaneous nonlinear dynamics should be captured online. A Chebyshev-wavelet embedded NeuroFuzzy indirect adaptive MPPT (maximum power point tracking) control paradigm is proposed for variable speed wind turbine-permanent synchronous generator (VSWT-PMSG). A Hermite-wavelet incorporated NeuroFuzzy indirect adaptive MPPT control strategy for photovoltaic (PV) system to extract maximum power and indirect adaptive tracking control scheme for Solid Oxide Fuel Cell (SOFC) is developed. A comprehensive simulation test-bed for a grid-connected hybrid power system is developed in Matlab/Simulink. The robustness of the suggested indirect adaptive control paradigms are evaluated through simulation results in a grid-connected hybrid power system test-bed by comparison with conventional and intelligent control techniques. The simulation results validate the effectiveness of the proposed control paradigms. PMID:28877191

  10. Modeling and Simulation for an 8 kW Three-Phase Grid-Connected Photo-Voltaic Power System

    OpenAIRE

    Cen Zhaohui

    2017-01-01

    Gird-connected Photo-Voltaic (PV) systems rated as 5-10 kW level have advantages of scalability and energy-saving, so they are very typical for small-scale household solar applications. In this paper, an 8 kW three-phase grid-connected PV system model is proposed and studied. In this high-fidelity model, some basic PV system components such as solar panels, DC-DC converters, DC-AC inverters and three-phase utility grids are mathematically modelled and organized as a complete simulation model....

  11. Design of A Grid Integrated PV System with MPPT Control and Voltage Oriented Controller using MATLAB/PLECES

    Science.gov (United States)

    Soreng, Bineeta; Behera, Pradyumna; Pradhan, Raseswari

    2017-08-01

    This paper presents model of a grid-integrated photovoltaic array with Maximum Power Point Tracker (MPPT) and voltage oriented controller. The MPPT of the PV array is usually an essential part of PV system as MPPT helps the operating point of the solar array to align its maximum power point. In this model, the MPPT along with a DC-DC converter lets a PV generator to produce continuous power, despite of the measurement conditions. The neutral-point-clamped converter (NPC) with a boost converter raises the voltage from the panels to the DC-link. An LCL-filter smoothens the current ripple caused by the PWM modulation of the grid-side inverter. In addition to the MPPT, the system has two more two controllers, such as voltage controller and a current controller. The voltage control has a PI controller to regulate the PV voltage to optimal level by controlling the amount of current injected into the boost stage. Here, the grid-side converter transfers the power from the DC-link into the grid and maintains the DC-link voltage. Three-phase PV inverters are used for off-grid or designed to create utility frequency AC. The PV system can be connected in series or parallel to get the desired output power. To justify the working of this model, the grid-integrated PV system has been designed in MATLAB/PLECS. The simulation shows the P-V curve of implemented PV Array consisting 4 X 20 modules, reactive, real power, grid voltage and current.

  12. Speed Sensorless vector control of parallel-connected three-phase two-motor single-inverter drive system

    DEFF Research Database (Denmark)

    Gunabalan, Ramachandiran; Sanjeevikumar, Padmanaban; Blaabjerg, Frede

    2016-01-01

    to noise and parameter uncertainty. The gain matrix is absent in the natural observer. The rotor speed is estimated from the load torque, stator current, and rotor flux. Under symmetrical load conditions, the difference in speed between two induction motors is reduced by considering the motor parameters......This paper presents the characteristic behavior of direct vector control of two induction motors with sensorless speed feedback having the same rating parameters, paralleled combination, and supplied from a single current-controlled pulse-width-modulated voltage-source inverter drive. Natural...... observer design technique is known for its simple construction, which estimates the speed and rotor fluxes. Load torque is estimated by load torque adaptation and the average rotor flux was maintained constant by rotor flux feedback control. The technique’s convergence rate is very fast and is robust...

  13. Research on Discretization PI Control Technology of Single-Phase Grid-Connected Inverter with LCL Filter

    Directory of Open Access Journals (Sweden)

    Jianke Li

    2014-01-01

    Full Text Available Compared with L-type filter, LCL-type filter is more suitable for high-power low-switching frequency applications with reducing the inductance, improving dynamic performance. However, the parameter design for the LCL filter is more complex due to the influence of the controller response performance of the converter. If the harmonic current around switching frequency can be fully suppressed, it is possible for inverter to decrease the total inductance as well as the size and the cost. In this paper, the model of the LCL filter is analyzed and numerical algorithms are adopted to analyze the stability of the closed-loop control system and stable regions are deduced with different parameters of LCL filter. Then, the minimum sampling frequencies are deduced with different conditions. Simulation and experimental results are provided to validate the research on the generating mechanism for the unstable region of sampling frequency.

  14. Reliability consideration of low-power-grid-tied inverter for photovoltaic application

    OpenAIRE

    Liu, J.; Henze, N.

    2009-01-01

    In recent years PV modules have been improved evidently. An excellent reliability has been validated corresponding to Mean Time between Failure (MTBF) between 500 and 6000 years respectively in commercial utility power systems. Manufactures can provide performance guarantees for PV modules at least for 20 years. If an average inverter lifetime of 5 years is assumed, it is evident that the overall reliability of PV systems [PVSs] with integrated inverter is determined chiefly by the inverter i...

  15. Analysis of measured and simulated performance data of a 3.2 kWp grid-connected PV system in Port Elizabeth, South Africa

    International Nuclear Information System (INIS)

    Okello, D.; Dyk, E.E. van; Vorster, F.J.

    2015-01-01

    Highlights: • Comparisons between actual measured and simulated performance of a grid-connected PV system. • Simulation using measured climate data sets gave good monthly energy yield comparisons to the measured. • The measured performance ratio of 84.3% shows vast solar energy potential in Eastern Cape region of South Africa. • Better annual specific yield is observed in this study compared to other studies internationally. - Abstract: This paper analyzes and compares the actual measured and simulated performance of a 3.2 kWp grid-connected photovoltaic system. The system is located at the Outdoor Research Facility (34.01°S, 25.67°E) at the Nelson Mandela Metropolitan University (NMMU), South Africa. The system consists of 14 poly crystalline silicon modules connected in two strings of 7 series-connected modules, each facing north at a fixed tilt of 34°. The data presented in this study were measured in the year 2013, where the system supplied a total of 5757 kW h to the local electric utility grid. The performance of the system was simulated using PVsyst software using measured and Meteonorm derived climate data sets (solar radiation, ambient temperature and wind speed). The comparison between measured and simulated energy yield are discussed. Although, both simulation results were similar, better comparison between measured and predicted monthly energy yield is observed with simulation performed using measured weather data at the site. The measured performance ratio in the present study is 84% which is slightly higher than values of 74%, 81.5%, 67.4%, 70% and 64.5% reported is Khatkar-Kalan (India), Dublin (Ireland), Crete (Greece), Karnataka (India) and Malaga (Spain), respectively

  16. An improved synchronous reference frame current control strategy for a photovoltaic grid-connected inverter under unbalanced and nonlinear load conditions

    DEFF Research Database (Denmark)

    Naderipour, Amirreza; Asuhaimi Mohd Zin, Abdullah; Bin Habibuddin, Mohd Hafiz

    2017-01-01

    In recent years, renewable energy sources have been considered the most encouraging resources for grid and off-grid power generation. This paper presents an improved current control strategy for a three-phase photovoltaic grid-connected inverter (GCI) under unbalanced and nonlinear load conditions....... It is challenging to suppress the harmonic content in the output current below a pre-set value in the GCI. It is also difficult to compensate for unbalanced loads even when the grid is under disruption due to total harmonic distortion (THD) and unbalanced loads. The primary advantage and objective of this method...... is to effectively compensate for the harmonic current content of the grid current and microgrid without the use of any compensation devices, such as active and passive filters. This method leads to a very low THD in both the GCI currents and the current exchanged with the grid. The control approach is designed...

  17. PV monitoring at Jubilee Campus - Nottingham University

    Energy Technology Data Exchange (ETDEWEB)

    Riffat, S.B.; Gan, G.

    2002-07-01

    This report summarises the results of a project monitoring the efficiency of photovoltaic (PV) modules integrated in the roofs of atria to meet the energy consumption needs of ventilation fans in the academic buildings at the Jubilee Campus of the University of Nottingham. Details are given of the instrumentation of one atrium to allow the monitoring the effectiveness of the ventilation in cooling the PV arrays integrated in the atrium roof, the economic analysis of the benefit of cooling the PV system, and the use of computational fluid dynamics (CFD) modelling to predict the performance of the atrium. The design of the PV system, the calculated system efficiency, the high cost of atrium integrated PV power supplies, the periodic failure of the inverters, and the overheating of the PV array and the atrium space in the summer are discussed.

  18. Investigation of extra power loss sharing among photovoltaic inverters caused by reactive power management in distribution networks

    DEFF Research Database (Denmark)

    Demirok, Erhan; Sera, Dezso; Teodorescu, Remus

    2014-01-01

    load and power loss on the feeders and individual inverters. Simplified energy loss evaluation is carried out here by using analytical average loss modeling of 2-level full bridge inverter coupled with network load flow analysis simulating one month period. The study shows that whatever Q control......Grid-connected photovoltaic (PV) inverters tailored with reactive power management feature can support the grid voltage especially when the voltage fluctuates near its admissible limits. Although Q control allows reducing the grid voltage elevation along the distribution feeder, it brings extra...... is selected, extra power loss is not a substantial amount to take into consideration. Similarly, loss difference among the inverters located at the various points is negligible....

  19. Optimized Sizing, Selection, and Economic Analysis of Battery Energy Storage for Grid-Connected Wind-PV Hybrid System

    OpenAIRE

    Fathima, Hina; Palanisamy, K.

    2015-01-01

    Energy storages are emerging as a predominant sector for renewable energy applications. This paper focuses on a feasibility study to integrate battery energy storage with a hybrid wind-solar grid-connected power system to effectively dispatch wind power by incorporating peak shaving and ramp rate limiting. The sizing methodology is optimized using bat optimization algorithm to minimize the cost of investment and losses incurred by the system in form of load shedding and wind curtailment. The ...

  20. Multilevel DC link inverter

    Science.gov (United States)

    Su, Gui-Jia

    2003-06-10

    A multilevel DC link inverter and method for improving torque response and current regulation in permanent magnet motors and switched reluctance motors having a low inductance includes a plurality of voltage controlled cells connected in series for applying a resulting dc voltage comprised of one or more incremental dc voltages. The cells are provided with switches for increasing the resulting applied dc voltage as speed and back EMF increase, while limiting the voltage that is applied to the commutation switches to perform PWM or dc voltage stepping functions, so as to limit current ripple in the stator windings below an acceptable level, typically 5%. Several embodiments are disclosed including inverters using IGBT's, inverters using thyristors. All of the inverters are operable in both motoring and regenerating modes.

  1. Artificial neural networks for control of a grid-connected rectifier/inverter under disturbance, dynamic and power converter switching conditions.

    Science.gov (United States)

    Li, Shuhui; Fairbank, Michael; Johnson, Cameron; Wunsch, Donald C; Alonso, Eduardo; Proaño, Julio L

    2014-04-01

    Three-phase grid-connected converters are widely used in renewable and electric power system applications. Traditionally, grid-connected converters are controlled with standard decoupled d-q vector control mechanisms. However, recent studies indicate that such mechanisms show limitations in their applicability to dynamic systems. This paper investigates how to mitigate such restrictions using a neural network to control a grid-connected rectifier/inverter. The neural network implements a dynamic programming algorithm and is trained by using back-propagation through time. To enhance performance and stability under disturbance, additional strategies are adopted, including the use of integrals of error signals to the network inputs and the introduction of grid disturbance voltage to the outputs of a well-trained network. The performance of the neural-network controller is studied under typical vector control conditions and compared against conventional vector control methods, which demonstrates that the neural vector control strategy proposed in this paper is effective. Even in dynamic and power converter switching environments, the neural vector controller shows strong ability to trace rapidly changing reference commands, tolerate system disturbances, and satisfy control requirements for a faulted power system.

  2. Single Stage String Inverter for Gridconnected Photovoltaic System with Modified Perturb and Observe (P&O Fuzzy Logic Control(FLC-based MPPT Technique

    Directory of Open Access Journals (Sweden)

    S.Z.Mohammad Noor

    2016-06-01

    Full Text Available This paper presents an implementation of Single-phase Single stage String inverter for Grid connected Photovoltaic (PV system. The proposed system uses Modified Perturb and Observe (P&O algorithm implemented using Fuzzy Logic Control (FLC as Maximum Power Point Tracking (MPPT. The inverter is designed for 340W system using two series of STP170s24/Ac PV modules. The MPPT unit keeps tracking the maximum power from the PV array by changing the modulation index and the phase angle of inverter’s output voltage. The simulation model is developed using Matlab/Simulink to evaluate the performance of the converter. Selected experimental results are also presented in this paper.

  3. Wide-band gap devices in PV systems - opportunities and challenges

    DEFF Research Database (Denmark)

    Sintamarean, Nicolae Cristian; Eni, Emanuel-Petre; Blaabjerg, Frede

    2014-01-01

    have an important role in the cost reduction. To increase the efficiency of PV systems, most of solutions for PV inverters have moved to three-level (3L) structures reaching typical efficiencies of 98% due to low switching losses of 600V Si IGBT or MOSFET and reduced core losses in the filter......The recent developments in wide band-gap devices based GaN and SiC is showing a high impact on the PV-inverter technology, which is strongly influenced by efficiency, power density and cost. Besides the high efficiency of PV inverters, also the mechanical size, the compactness and simple structure......) three-phase PV-inverter topologies in terms of efficiency, thermal loading distribution and costs. Moreover the above mentioned PV-inverters are built and tested in laboratory in order to validate the obtained results....

  4. Control Strategy of Two Capacitor Voltages for Separate MPPTs in Photovoltaic Systems Using Neutral-Point-Clamped Inverters

    DEFF Research Database (Denmark)

    Choi, Ui-Min; Blaabjerg, Frede; Lee, Kyo-Beum

    2015-01-01

    The centralized topology with three-level inverters are widely used in photovoltaic (PV) systems due to their less installation costs and complexity. However, the common maximum power point tracking (MPPT) is a disadvantage of the centralized topology particularly under the partial shading...... and panel mismatch conditions. In this system, if PV modules are separately connected to the split capacitor voltage, the MPPT efficiency can be improved by the proposed control strategy. By the proposed method, the two capacitor voltages can be controlled asymmetrically to perform the separate MPPTs...... of each PV module connected to separate capacitors. The outputs can be generated without distortion even if two capacitors are asymmetrically regulated. Simulation and experimental results verify the validity and feasibility of the proposed methods....

  5. Step by Step Design of a High Order Power Filter for Three-Phase Three-Wire Grid-connected Inverter in Renewable Energy System

    DEFF Research Database (Denmark)

    Huang, Min; Blaabjerg, Frede; Yang, Yongheng

    2013-01-01

    -tied system, the output current harmonics of inverter are directly affected by the output line to line voltage. Hence, this paper proposes a new method to analyze the inverter output current harmonics by using the equivalent phase voltage of the three phase inverter. Based on this, a step by step design...

  6. Performance analysis of PV plants: Optimization for improving profitability

    International Nuclear Information System (INIS)

    Díez-Mediavilla, M.; Alonso-Tristán, C.; Rodríguez-Amigo, M.C.; García-Calderón, T.; Dieste-Velasco, M.I.

    2012-01-01

    Highlights: ► Real PV production from two 100 kW p grid-connected installations is conducted. ► Data sets on production were collected over an entire year. ► Economic results highlight the importance of properly selecting the system components. ► Performance of PV plants is directly related to improvements of all components. - Abstract: A study is conducted of real PV production from two 100 kW p grid-connected installations located in the same area, both of which experience the same fluctuations in temperature and radiation. Data sets on production were collected over an entire year and both installations were compared under various levels of radiation. The installations were assembled with mono-Si panels, mounted on the same support system, and the power supply was equal for the inverter and the measurement system; the same parameters were also employed for the wiring, and electrical losses were calculated in both cases. The results, in economic terms, highlight the importance of properly selecting the system components and the design parameters for maximum profitability.

  7. Inverted oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Yuce, C [Physics Department, Anadolu University, Eskisehir (Turkey); Kilic, A [Physics Department, Anadolu University, Eskisehir (Turkey); Coruh, A [Physics Department, Sakarya University, Sakarya (Turkey)

    2006-07-15

    The inverted harmonic oscillator problem is investigated quantum mechanically. The exact wavefunction for the confined inverted oscillator is obtained and it is shown that the associated energy eigenvalues are discrete, and the energy is given as a linear function of the quantum number n.

  8. Grid-Forming-Mode Operation of Boost-Power-Stage Converter in PV-Generator-Interfacing Applications

    Directory of Open Access Journals (Sweden)

    Jukka Viinamäki

    2017-07-01

    Full Text Available The application of constant power control and inclusion of energy storage in grid-connected photovoltaic (PV energy systems may increase the use of two-stage system structures composed of DC–DC-converter-interfaced PV generator and grid-connected inverter connected in cascade. A typical PV-generator-interfacing DC–DC converter is a boost-power-stage converter. The renewable energy system may operate in three different operation modes—grid-forming, grid-feeding, and grid-supporting modes. In the last two operation modes, the outmost feedback loops are taken from the input terminal of the associated power electronic converters, which usually does not pose stability problems in terms of their input sources. In the grid-forming operation mode, the outmost feedback loops have to be connected to the output terminal of the associated power electronic converters, and hence the input terminal will behave as a negative incremental resistor at low frequencies. This property will limit the operation of the PV interfacing converter in either the constant voltage or constant current region of the PV generator for ensuring stable operation. The boost-power-stage converter can be applied as a voltage or current-fed converter limiting the stable operation region accordingly. The investigations of this paper show explicitly that only the voltage-fed mode would provide feasible dynamic and stability properties as a viable interfacing converter.

  9. A new PLL system using full order observer and PLL system modeling in a single phase grid-connected inverter

    DEFF Research Database (Denmark)

    Ko, Youngjong; Park, Kiwoo; Lee, Kyo-Beum

    2011-01-01

    In a grid connected power conversion system, the phase angle information of a grid voltage is very essential for supplying power to the grid since it is used for active and reactive power control. A Phase Locked Loop (PLL) system is used and should be robust because often the actual grid voltages...

  10. Design of LCL-filters with LCL resonance frequencies beyond the Nyquist frequency for grid-connected inverters

    DEFF Research Database (Denmark)

    Tang, Yi; Yao, Wenli; Loh, Poh Chiang

    2015-01-01

    , and this observation is so far not discussed in the literature. In this case, very cost-effective LCL-filter design can be achieved for grid-connected converters whose dominant switching harmonics may appear at double of the switching frequency, e.g. in unipolar modulated three-level full bridge converters and 12...

  11. LonWorks as Fieldbus for PV-Installations; LonWorks als Feldbus fuer PV-Anlagen

    Energy Technology Data Exchange (ETDEWEB)

    Bergen, Ch. von

    2003-07-01

    The growing market for photovoltaics increasingly requires suitable quality controls covering plant operators, planners and installers, as well as the electric utilities. Additionally, the interest of the general public in the behaviour of photovoltaic (PV) plants is growing. This includes information from everyday practice. Alongside data retrieval, other themes such as the operative management of the unit and energy management become increasingly important for grid-connected PV systems. Todays measuring systems are not compatible with each other. Data communication between different PV plants with computer-aided analysis- and visualisation programmes is very complicated. LonWorks was introduced by Motorola and Toshiba in 1991. Today it leads the world market for field bus systems. With plug and play, components by several manufacturers can easily be incorporated into a LonWorks network. Today more than 3,500 companies use LonWorks technology. The goal of this project is to introduce the very popular LonWorks technology as a new standard for PV applications. The first objective was to develop a LonWorks interface for our Convert inverters and to connect them into a small network. In a second step we installed a LonWorks system at the 260 kW{sub p} PV plant 'Felsenau' in Berne, Switzerland. All 68 inverters are controlled over power line with LonWorks. The on-site PC acts as LonWorks DataServer and making remote information monitoring and data gathering possible. As soon as a functional error occurs, an alarm will be transmitted via modem to the SMSC (Short Message Service Centre). After two years of operation we can say that all expectations were fulfilled by our new system. Knowledge gained from this project has shown that LonWorks has lived up its considerable promise and can be regarded as a high-quality piece of technology. Integration into an overall system is technically very easy. To do this, however, relatively expensive software solutions have

  12. Assessing the influence of the temporal resolution of electrical load and PV generation profiles on self-consumption and sizing of PV-battery systems

    International Nuclear Information System (INIS)

    Beck, T.; Kondziella, H.; Huard, G.; Bruckner, T.

    2016-01-01

    Highlights: • MILP optimization model for operation and investment of PV-battery systems. • Use of high resolution (10 s) electrical household load and PV generation profiles. • Analysis of influence of temporal resolution on self-consumption and optimal sizing. • Electrical load profile characteristics influence required temporal resolution. - Abstract: The interest in self-consumption of electricity generated by rooftop photovoltaic systems has grown in recent years, fueled by decreasing levelized costs of electricity and feed-in tariffs as well as increasing end customer electricity prices in the residential sector. This also fostered research on grid-connected PV-battery storage systems, which are a promising technology to increase self-consumption. In this paper a mixed-integer linear optimization model of a PV-battery system that minimizes the total discounted operating and investment costs is developed. The model is employed to study the effect of the temporal resolution of electrical load and PV generation profiles on the rate of self-consumption and the optimal sizing of PV and PV-battery systems. In contrast to previous studies high resolution (10 s) measured input data for both PV generation and electrical load profiles is used for the analysis. The data was obtained by smart meter measurements in 25 different households in Germany. It is shown that the temporal resolution of load profiles is more critical for the accuracy of the determination of self-consumption rates than the resolution of the PV generation. For PV-systems without additional storage accurate results can be obtained by using 15 min solar irradiation data. The required accuracy for the electrical load profiles depends strongly on the load profile characteristics. While good results can be obtained with 60 s for all electrical load profiles, 15 min data can still be sufficient for load profiles that do not exhibit most of their electricity consumption at power levels above 2 k

  13. A solar PV augmented hybrid scheme for enhanced wind power generation through improved control strategy for grid connected doubly fed induction generator

    Directory of Open Access Journals (Sweden)

    Adikanda Parida

    2016-12-01

    Full Text Available In this paper, a wind power generation scheme using a grid connected doubly fed induction generator (DFIG augmented with solar PV has been proposed. A reactive power-based rotor speed and position estimation technique with reduced machine parameter sensitivity is also proposed to improve the performance of the DFIG controller. The estimation algorithm is based on model reference adaptive system (MRAS, which uses the air gap reactive power as the adjustable variable. The overall generation reliability of the wind energy conversion system can be considerably improved as both solar and wind energy can supplement each other during lean periods of either of the sources. The rotor-side DC-link voltage and active power generation at the stator terminals of the DFIG are maintained constant with minimum storage battery capacity using single converter arrangement without grid-side converter (GSC. The proposed scheme has been simulated and experimentally validated with a practical 2.5 kW DFIG using dSPACE CP1104 module which produced satisfactory results.

  14. Optimized Sizing, Selection, and Economic Analysis of Battery Energy Storage for Grid-Connected Wind-PV Hybrid System

    Directory of Open Access Journals (Sweden)

    Hina Fathima

    2015-01-01

    Full Text Available Energy storages are emerging as a predominant sector for renewable energy applications. This paper focuses on a feasibility study to integrate battery energy storage with a hybrid wind-solar grid-connected power system to effectively dispatch wind power by incorporating peak shaving and ramp rate limiting. The sizing methodology is optimized using bat optimization algorithm to minimize the cost of investment and losses incurred by the system in form of load shedding and wind curtailment. The integrated system is then tested with an efficient battery management strategy which prevents overcharging/discharging of the battery. In the study, five major types of battery systems are considered and analyzed. They are evaluated and compared based on technoeconomic and environmental metrics as per Indian power market scenario. Technoeconomic analysis of the battery is validated by simulations, on a proposed wind-photovoltaic system in a wind site in Southern India. Environmental analysis is performed by evaluating the avoided cost of emissions.

  15. Analytical Investigation and Control System Set-up of Medium Scale PV Plants for Power Flow Management

    Directory of Open Access Journals (Sweden)

    Rosario Miceli

    2012-11-01

    Full Text Available In the field of photovoltaic (PV plants and energy conversion from renewable sources, a large part of the technical literature is more devoted to practical aspects (new solar cells, electrically driven PV panels, safety, reduction of parasitic currents, etc. than to theoretical investigations. Despite this tendency, this paper presents a mathematical analysis of a medium scale photovoltaic power generation system connected to the distribution network and of its control system. In such a system, the conversion stage is unique due to the absence of a boost chopper. The conducted analysis leads to the interesting conclusion that the inverter used in the plant presents two degrees of freedom, easy to exploit in a control system in which the inverter simultaneously realizes the interconnection to the grid and the MPPT control. The structure of the control system is then presented, discussed and validated by means of numerical simulations.

  16. PV-HYBRID and MINI-GRID. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    Within the 3rd European Conference at the Centre de Congres in Aix en Provence (France) between 11th and 12th May, 2006, the following lessons were held: (1) Small electric networks: European drivers and projects for the integration of RES and DG into the electricity grids of the future (Manuel Sanchez-Jimenez); (2) PV hybrid system within mini grids - IEA PVPS programme (Meuch Konraf); (3) Renewables for the developing world (Alvaro Ponce Plaza); (4) Rural electicity supply using photovoltaic / - Diesel hybrid systems: Attractive for investors in the renewable energy sector? (Andreas Hahn); (5) Economic analysis of stand-alone and grid-connected photovoltaic systems under current tariff structure of Taiwan (Yaw-Juen Wang); (6) Using wind-PV-diesel hybrid system for electrification of remote village in Western Libya (N.M. Kreama); (7) Venezuela's renewable energy program for small towns and rural areas ''Sembrando Luz'' (Jorge Torres); (8) AeroSmart5, the professional, sysem-compatible small-scale wind energy converter will be tested in field tests (Fabian Jochem); (9) Lifetime, test procedures and recommendations for optimal operating strategies for lead-acid-batteries in renewable energy systems - A survey on results from European projects from the 5th framework programme (Rudi Kaiser); (10) Prototype of a reversible fuel cell system for autonomous power supplies (Tom Smolinska); (11) Interconnection management in microgrids (Michel Vandenbergh); (12) Control strategy for a small-scale stand-alone power system based on renewable energy and hydrogen (Harald Miland); (13) Standard renewable electricity supply for people in rural areas - mini-grids in western provinces of China (Michael Wollny); (14) The Brava island a ''100% renewable energy'' project (Jean-Christian Marcel); (15) Breakthrough to a new era of PV-hybrid systems with the help of standardised components communication? (Michael Mueller); (16) Standardized

  17. Robustness analysis of active damping methods for an inverter connected to the grid with an LCL-filter

    DEFF Research Database (Denmark)

    Ricchiuto, D.; Liserre, M.; Kerekes, Tamas

    2011-01-01

    Grid-connected converters usually employ an LCL-filter to reduce PWM harmonics. To avoid the wellknown stability problems it is requested to use either passive or active damping methods. Active damping methods avoid losses and preserve the filter effectiveness but they are more sensitive...... to parameters variation. In this paper the robustness of active damping methods is investigated considering those using only the same state variable (grid-side or converter-side current) normally used for current control (filter-based) or those methods using more state-variables (multiloop). Simulation...

  18. The active control strategy on the output power for photovoltaic-storage systems based on extended PQ-QV-PV Node

    Science.gov (United States)

    Xu, Chen; Zhou, Bao-Rong; Zhai, Jian-Wei; Zhang, Yong-Jun; Yi, Ying-Qi

    2017-05-01

    In order to solve the problem of voltage exceeding specified limits and improve the penetration of photovoltaic in distribution network, we can make full use of the active power regulation ability of energy storage(ES) and the reactive power regulation ability of grid-connected photovoltaic inverter to provide support of active power and reactive power for distribution network. A strategy of actively controlling the output power for photovoltaic-storage system based on extended PQ-QV-PV node by analyzing the voltage regulating mechanism of point of commom coupling(PCC) of photovoltaic with energy storage(PVES) by controlling photovoltaic inverter and energy storage. The strategy set a small wave range of voltage to every photovoltaic by making the type of PCC convert among PQ, PV and QV. The simulation results indicate that the active control method can provide a better solution to the problem of voltage exceeding specified limits when photovoltaic is connectted to electric distribution network.

  19. The Modeling and Harmonic Coupling Analysis of Multiple-Parallel Connected Inverter Using Harmonic State Space (HSS)

    DEFF Research Database (Denmark)

    Kwon, Jun Bum; Wang, Xiongfei; Bak, Claus Leth

    2015-01-01

    As the number of power electronics based systems are increasing, studies about overall stability and harmonic problems are rising. In order to analyze harmonics and stability, most research is using an analysis method, which is based on the Linear Time Invariant (LTI) approach. However, this can...... be difficult in terms of complex multi-parallel connected systems, especially in the case of renewable energy, where possibilities for intermittent operation due to the weather conditions exist. Hence, it can bring many different operating points to the power converter, and the impedance characteristics can...... can demonstrate other phenomenon, which can not be found in the conventional LTI approach. The theoretical modeling and analysis are verified by means of simulations and experiments....

  20. Simulation of Hawaiian Electric Companies Feeder Operations with Advanced Inverters and Analysis of Annual Photovoltaic Energy Curtailment

    Energy Technology Data Exchange (ETDEWEB)

    Giraldez Miner, Julieta I [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Nagarajan, Adarsh [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Gotseff, Peter [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Krishnan, Venkat K [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Hoke, Anderson F [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Ueda, Reid [Hawaiian Electric Company; Shindo, Jon [Hawaiian Electric Company; Asano, Marc [Hawaiian Electric Company; Ifuku, Earle [Hawaiian Electric Company

    2017-07-26

    The Hawaiian Electric Companies achieved a consolidated Renewable Portfolio Standard (RPS) of approximately 26% at the end of 2016. This significant RPS performance was achieved using various renewable energy sources - biomass, geothermal, solar photovoltaic (PV) systems, hydro, wind, and biofuels - and customer-sited, grid-connected technologies (primarily private rooftop solar PV systems). The Hawaiian Electric Companies are preparing grid-modernization plans for the island grids. The plans outline specific near-term actions to accelerate the achievement of Hawai'i's 100% RPS by 2045. A key element of the Companies' grid-modernization strategy is to utilize new technologies - including storage and PV systems with grid-supportive inverters - that will help to more than triple the amount of private rooftop solar PV systems. The Hawaiian Electric Companies collaborated with the Smart Inverter Technical Working Group Hawai'i (SITWG) to partner with the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) to research the implementation of advanced inverter grid support functions (GSF). Together with the technical guidance from the Companies's planning engineers and stakeholder input from the SITWG members, NREL proposed a scope of work that explored different modes of voltage-regulation GSF to better understand the trade-offs of the grid benefits and curtailment impacts from the activation of selected advanced inverter grid support functions. The simulation results presented in this report examine the effectiveness in regulating voltage as well as the impact to the utility and the customers of various inverter-based grid support functions on two Hawaiian Electric distribution substations.

  1. Control of Grid Connected Photovoltaic Systems with Microinverters

    DEFF Research Database (Denmark)

    Yahya, Abdelhafid; El Fadil, Hassan; Oulcaid, Mustapha

    2018-01-01

    This paper addresses the problem of controlling grid connected photovoltaic (PV) systems that are driven with microinverters. The systems to be controlled consist of a solar panel, a boost dc–dc converter, a DC link capacitor, a single-phase full-bridge inverter, a filter inductor, and an isolation...... transformer. We seek controllers that are able to simultaneously achieve four control objectives, namely: (i) asymptotic stability of the closed loop control system; (ii) maximum power point tracking (MPPT) of the PV module; (iii) tight regulation of the DC bus voltage; and (iv) unity power factor (PF...

  2. Grid-connected photovoltaic power systems. Technical and potential problems. A review

    International Nuclear Information System (INIS)

    Eltawil, Mohamed A.; Zhao, Zhengming

    2010-01-01

    Traditional electric power systems are designed in large part to utilize large baseload power plants, with limited ability to rapidly ramp output or reduce output below a certain level. The increase in demand variability created by intermittent sources such as photovoltaic (PV) presents new challenges to increase system flexibility. This paper aims to investigate and emphasize the importance of the grid-connected PV system regarding the intermittent nature of renewable generation, and the characterization of PV generation with regard to grid code compliance. The investigation was conducted to critically review the literature on expected potential problems associated with high penetration levels and islanding prevention methods of grid tied PV. According to the survey, PV grid connection inverters have fairly good performance. They have high conversion efficiency and power factor exceeding 90% for wide operating range, while maintaining current harmonics THD less than 5%. Numerous large-scale projects are currently being commissioned, with more planned for the near future. Prices of both PV and balance of system components (BOS) are decreasing which will lead to further increase in use. The technical requirements from the utility power system side need to be satisfied to ensure the safety of the PV installer and the reliability of the utility grid. Identifying the technical requirements for grid interconnection and solving the interconnect problems such as islanding detection, harmonic distortion requirements and electromagnetic interference are therefore very important issues for widespread application of PV systems. The control circuit also provides sufficient control and protection functions like maximum power tracking, inverter current control and power factor control. Reliability, life span and maintenance needs should be certified through the long-term operation of PV system. Further reduction of cost, size and weight is required for more utilization of PV

  3. Modeling and Simulation for an 8 kW Three-Phase Grid-Connected Photo-Voltaic Power System

    Science.gov (United States)

    Cen, Zhaohui

    2017-09-01

    Gird-connected Photo-Voltaic (PV) systems rated as 5-10 kW level have advantages of scalability and energy-saving, so they are very typical for small-scale household solar applications. In this paper, an 8 kW three-phase grid-connected PV system model is proposed and studied. In this high-fidelity model, some basic PV system components such as solar panels, DC-DC converters, DC-AC inverters and three-phase utility grids are mathematically modelled and organized as a complete simulation model. Also, an overall power controller with Maximum Power Point Control (MPPT) is proposed to achieve both high-efficiency for solar energy harvesting and grid-connection stability. Finally, simulation results demonstrate the effectiveness of the PV system model and the proposed controller, and power quality issues are discussed.

  4. Modeling and Simulation for an 8 kW Three-Phase Grid-Connected Photo-Voltaic Power System

    Directory of Open Access Journals (Sweden)

    Cen Zhaohui

    2017-09-01

    Full Text Available Gird-connected Photo-Voltaic (PV systems rated as 5-10 kW level have advantages of scalability and energy-saving, so they are very typical for small-scale household solar applications. In this paper, an 8 kW three-phase grid-connected PV system model is proposed and studied. In this high-fidelity model, some basic PV system components such as solar panels, DC-DC converters, DC-AC inverters and three-phase utility grids are mathematically modelled and organized as a complete simulation model. Also, an overall power controller with Maximum Power Point Control (MPPT is proposed to achieve both high-efficiency for solar energy harvesting and grid-connection stability. Finally, simulation results demonstrate the effectiveness of the PV system model and the proposed controller, and power quality issues are discussed.

  5. An improved synchronous reference frame current control strategy for a photovoltaic grid-connected inverter under unbalanced and nonlinear load conditions

    Science.gov (United States)

    Naderipour, Amirreza; Asuhaimi Mohd Zin, Abdullah; Bin Habibuddin, Mohd Hafiz; Miveh, Mohammad Reza; Guerrero, Josep M.

    2017-01-01

    In recent years, renewable energy sources have been considered the most encouraging resources for grid and off-grid power generation. This paper presents an improved current control strategy for a three-phase photovoltaic grid-connected inverter (GCI) under unbalanced and nonlinear load conditions. It is challenging to suppress the harmonic content in the output current below a pre-set value in the GCI. It is also difficult to compensate for unbalanced loads even when the grid is under disruption due to total harmonic distortion (THD) and unbalanced loads. The primary advantage and objective of this method is to effectively compensate for the harmonic current content of the grid current and microgrid without the use of any compensation devices, such as active and passive filters. This method leads to a very low THD in both the GCI currents and the current exchanged with the grid. The control approach is designed to control the active and reactive power and harmonic current compensation, and it also corrects the system unbalance. The proposed control method features the synchronous reference frame (SRF) method. Simulation results are presented to demonstrate the effective performance of the proposed method. PMID:28192436

  6. An improved synchronous reference frame current control strategy for a photovoltaic grid-connected inverter under unbalanced and nonlinear load conditions.

    Science.gov (United States)

    Naderipour, Amirreza; Asuhaimi Mohd Zin, Abdullah; Bin Habibuddin, Mohd Hafiz; Miveh, Mohammad Reza; Guerrero, Josep M

    2017-01-01

    In recent years, renewable energy sources have been considered the most encouraging resources for grid and off-grid power generation. This paper presents an improved current control strategy for a three-phase photovoltaic grid-connected inverter (GCI) under unbalanced and nonlinear load conditions. It is challenging to suppress the harmonic content in the output current below a pre-set value in the GCI. It is also difficult to compensate for unbalanced loads even when the grid is under disruption due to total harmonic distortion (THD) and unbalanced loads. The primary advantage and objective of this method is to effectively compensate for the harmonic current content of the grid current and microgrid without the use of any compensation devices, such as active and passive filters. This method leads to a very low THD in both the GCI currents and the current exchanged with the grid. The control approach is designed to control the active and reactive power and harmonic current compensation, and it also corrects the system unbalance. The proposed control method features the synchronous reference frame (SRF) method. Simulation results are presented to demonstrate the effective performance of the proposed method.

  7. An Optimized Reactive Power Control of Distributed Solar Inverters in Low Voltage Networks

    DEFF Research Database (Denmark)

    Demirok, Erhan; Sera, Dezso; Teodorescu, Remus

    2011-01-01

    This study examines the reactive power ancillary services of solar inverters which are connected to low voltage (LV) distribution networks by giving attention to the grid voltage support service and grid losses. Two typical reference LV distribution network models as suburban and farm...... are introduced from the literature in order to evaluate contribution of two static droop strategies cosφ(P) and Q(U) on the grid voltage. Photovoltaic (PV) hosting capacities of the suburban and farm networks are estimated and the most predominant limitations of connecting more solar inverters are emphasized...... for each network type. Regarding the overloading of MV/LV distribution transformers, overloading of lines and the grid overvoltage limitations, new local grid voltage support methods (cosφ(P,U) and Q(U,P)) are also proposed. Resulting maximum allowable penetration levels with different reactive power...

  8. A Family of Cost-Effective Magnetically-Coupled Impedance Source Inverters

    DEFF Research Database (Denmark)

    Li, Kerui; Yang, Yongheng; Qin, Zian

    2017-01-01

    of required semiconductor switches is reduced. More important, the elimination of leakage currents makes it particularly suitable for high-efficiency photovoltaic (PV) applications. A comparison among prior-art PV inverters is then performed. The Performances of the inverters are evaluated analytically...

  9. Comparative Study Between Wind and Photovoltaic (PV) Systems

    Science.gov (United States)

    Taha, Wesam

    This paper reviews two renewable energy systems; wind and photovoltaic (PV) systems. The common debate between the two of them is to conclude which one is better, in terms of cost and efficiency. Therefore, comparative study, in terms of cost and efficiency, is attempted. Regarding total cost of both, wind and PV systems, many parameters must be taken into consideration such as availability of energy (either wind or solar), operation and maintenance, availability of costumers, political influence, and the components used in building the system. The main components and parameters that play major role in determining the overall efficiency of wind systems are the wind turbine generator (WTG), gearbox and control technologies such as power, and speed control. On the other hand, in grid-connected PV systems (GCPVS), converter architecture along with maximum power point tracking (MPPT) algorithm and inverter topologies are the issues that affects the efficiency significantly. Cost and efficiency analyses of both systems have been carried out based on the statistics available till today and would be useful in the progress of renewable energy penetration throughout the world.

  10. Experimental evaluation of 8kW grid-connected photovoltaic system in Egypt

    OpenAIRE

    Elkholy, A.; Fahmy, F.H.; Abou El-Ela, A.A.; Nafeh, Abd El-Shafy A.; Spea, S.R.

    2016-01-01

    An experimental observation study of 8 kW grid-connected photovoltaic (PV) system that is installed at Electronics Research Institute (ERI), Giza, Egypt (Latitude 30.04°N, Longitude 31.21°E), is presented. This study includes the quality of the electrical power generated and injected into the network. The considered system consists of 28 × 295 Wp multicrystalline PV modules, StecaGrid three-phase 8 kW grid-connected inverter and a Solar-Log 300 PM+ for data acquisition and remote monitoring. ...

  11. Harmonic analysis and suppression in hybrid wind & PV solar system

    Science.gov (United States)

    Gupta, Tripti; Namekar, Swapnil

    2018-04-01

    The growing demand of electricity has led to produce power through non-conventional source of energy such as solar energy, wind energy, hydro power, energy through biogas and biomass etc. Hybrid system is taken to complement the shortcoming of either sources of energy. The proposed system is grid connected hybrid wind and solar system. A 2.1 MW Doubly fed Induction Generator (DFIG) has been taken for analysis of wind farm whose rotor part is connected to two back-to-back converters. A 250 KW Photovoltaic (PV) array taken to analyze solar farm where inverter is required to convert power from DC to AC since electricity generated through solar PV is in the form of DC. Stability and reliability of the system is very important when the system is grid connected. Harmonics is the major Power quality issue which degrades the quality of power at load side. Harmonics in hybrid system arise through the use of power conversion unit. The other causes of harmonics are fluctuation in wind speed and solar irradiance. The power delivered to grid must be free from harmonics and within the limits specified by Indian grid codes. In proposed work, harmonic analysis of the hybrid system is performed in Electrical Transient Analysis program (ETAP) and single tuned harmonic filter is designed to maintain the utility grid harmonics within limits.

  12. Power Hardware-in-the-Loop Testing of Multiple Photovoltaic Inverters' Volt-Var Control with Real-Time Grid Model

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, Sudipta; Nelson, Austin; Hoke, Anderson

    2016-12-12

    Traditional testing methods fall short in evaluating interactions between multiple smart inverters providing advanced grid support functions due to the fact that such interactions largely depend on their placements on the electric distribution systems with impedances between them. Even though significant concerns have been raised by the utilities on the effects of such interactions, little effort has been made to evaluate them. In this paper, power hardware-in-the-loop (PHIL) based testing was utilized to evaluate autonomous volt-var operations of multiple smart photovoltaic (PV) inverters connected to a simple distribution feeder model. The results provided in this paper show that depending on volt-var control (VVC) parameters and grid parameters, interaction between inverters and between the inverter and the grid is possible in some extreme cases with very high VVC slopes, fast response times and large VVC response delays.

  13. Single phase cascaded H5 inverter with leakage current elimination for transformerless photovoltaic system

    DEFF Research Database (Denmark)

    Guo, Xiaoqiang; Jia, X.; Lu, Z.

    2016-01-01

    Leakage current reduction is one of the important issues for the transformelress PV systems. In this paper, the transformerless single-phase cascaded H-bridge PV inverter is investigated. The common mode model for the cascaded H4 inverter is analyzed. And the reason why the conventional cascade H4...... inverter fails to reduce the leakage current is clarified. In order to solve the problem, a new cascaded H5 inverter is proposed to solve the leakage current issue. Finally, the experimental results are presented to verify the effectiveness of the proposed topology with the leakage current reduction...... for the single-phase transformerless PV systems....

  14. Lightning Surge Analysis on a Large Scale Grid-Connected Solar Photovoltaic System

    Directory of Open Access Journals (Sweden)

    Nur Hazirah Zaini

    2017-12-01

    Full Text Available Solar photovoltaic (PV farms currently play a vital role in the generation of electrical power in different countries, such as Malaysia, which is moving toward the use of renewable energy. Malaysia is one of the countries with abundant sunlight and thus can use solar PV farms as alternative sources for electricity generation. However, lightning strikes frequently occur in the country. Being installed in open and flat areas, solar PV farms, especially their electronic components, are at great risk of damage caused by lightning. In this paper, the effects of lightning currents with different peak currents and waveshapes on grid-connected solar PV farms were determined to approximate the level of transient effect that can damage solar PV modules, inverters and transformers. Depending on the location of the solar PV farm, engineer can obtain information on the peak current and median current of the site from the lightning location system (LLS and utilise the results obtained in this study to appropriately assign an SPD to protect the solar panel, inverter and the main panel that connected to the grid. Therefore, the simulation results serve as the basis for controlling the effects of lightning strikes on electrical equipment and power grids where it provides proper justification on the ‘where to be installed’ and ‘what is the rating’ of the SPD. This judgment and decision will surely reduce the expensive cost of repair and replacement of electrical equipment damages due to the lightning.

  15. A Transformer-less Single Phase Inverter For photovoltaic Systems

    DEFF Research Database (Denmark)

    Mostaan, Ali; Alizadeh, Ebrahim; Qu, Ying

    2017-01-01

    A single phase transformer-less inverter is introduced in this paper. The negative polarities of the input voltage and output terminal have common ground. Therefore, the leakage current problem that is common in PV systems is eliminated naturally. In addition, the proposed inverter has fewer comp...

  16. Fast Grid Frequency Support from Distributed Inverter-Based Resources

    Energy Technology Data Exchange (ETDEWEB)

    Hoke, Anderson F [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-05-04

    This presentation summarizes power hardware-in-the-loop testing performed to evaluate the ability of distributed inverter-coupled generation to support grid frequency on the fastest time scales. The research found that distributed PV inverters and other DERs can effectively support the grid on sub-second time scales.

  17. Task 5. Grid interconnection of building integrated and other dispersed photovoltaic power systems. Grid-connected photovoltaic power systems: power value and capacity value of PV systems

    Energy Technology Data Exchange (ETDEWEB)

    Groppi, F.

    2002-02-15

    This report for the International Energy Agency (IEA) made by Task 5 of the Photovoltaic Power Systems (PVPS) programme takes a look at the power value and capacity value of photovoltaic power systems. The mission of the Photovoltaic Power Systems Programme is to enhance the international collaboration efforts which accelerate the development and deployment of photovoltaic solar energy. Task 5 deals with issues concerning grid-interconnection and dispersed PV power systems. This report summarises the results of a study aimed to assess the benefits that may be obtained when distributed PV production systems are present in a low-voltage grid. The basic aspects concerning the power-value and those related to the capacity-value are discussed. Data obtained from simulations are presented and discussed. A simple concept shows that great variation occurs if varying load patterns are taken into account. The power-value of PV generation in the grid varies instant by instant depending on the current level of power production and on the surrounding load conditions. Although the three case-studies considered do not cover all the possibilities of coupling between PV and loads, the results obtained show a good differentiation among users with PV production which leads to interesting conclusions.

  18. Comparison of measured and predicted long term performance of grid a connected photovoltaic system

    International Nuclear Information System (INIS)

    Mondol, Jayanta Deb; Yohanis, Yigzaw G.; Norton, Brian

    2007-01-01

    Predicted performance of a grid connected photovoltaic (PV) system using TRNSYS was compared with measured data. A site specific global-diffuse correlation model was developed and used to calculate the beam and diffuse components of global horizontal insolation. A PV module temperature equation and a correlation relating input and output power of an inverter were developed using measured data and used in TRNSYS to perform PV array and inverter outputs simulation. Different combinations of the tilted surface radiation model, global-diffuse correlation model and PV module temperature equation were used in the simulations. Statistical error analysis was performed to compare the results for each combination. The simulation accuracy was improved by using the new global-diffuse correlation and module temperature equation in the TRNSYS simulation. For an isotropic sky tilted surface radiation model, the average monthly difference between measured and predicted PV output before and after modification of the TRNSYS component were 10.2% and 3.3%, respectively, and, for an anisotropic sky model, 15.4% and 10.7%, respectively. For inverter output, the corresponding errors were 10.4% and 3.3% and 15.8% and 8.6%, respectively. Measured PV efficiency, overall system efficiency, inverter efficiency and performance ratio of the system were compared with the predicted results. The predicted PV performance parameters agreed more closely with the measured parameters in summer than in winter. The difference between predicted performances using an isotropic and an anisotropic sky tilted surface models is between 1% and 2%

  19. Three-Phase Cascaded Multilevel Inverter Using Power Cells With Two Inverter Legs in Series

    NARCIS (Netherlands)

    Waltrich, G.; Barbi, I.

    2010-01-01

    In this paper, a modular three-phase multilevel inverter specially suited for electrical drive applications is proposed. Unlike the cascaded H-bridge inverter, this topology is based on power cells connected in cascade using two inverter legs in series. A detailed analysis of the structure and the

  20. A Two-Stage Robust Optimization for Centralized-Optimal Dispatch of Photovoltaic Inverters in Active Distribution Networks

    DEFF Research Database (Denmark)

    Ding, Tao; Li, Cheng; Yang, Yongheng

    2017-01-01

    Optimally dispatching Photovoltaic (PV) inverters is an efficient way to avoid overvoltage in active distribution networks, which may occur in the case of PV generation surplus load demand. Typically, the dispatching optimization objective is to identify critical PV inverters that have the most...... nature of solar PV energy may affect the selection of the critical PV inverters and also the final optimal objective value. In order to address this issue, a two-stage robust optimization model is proposed in this paper to achieve a robust optimal solution to the PV inverter dispatch, which can hedge...... against any possible realization within the uncertain PV outputs. In addition, the conic relaxation-based branch flow formulation and second-order cone programming based column-and-constraint generation algorithm are employed to deal with the proposed robust optimization model. Case studies on a 33-bus...

  1. A Software Tool for Optimal Sizing of PV Systems in Malaysia

    Directory of Open Access Journals (Sweden)

    Tamer Khatib

    2012-01-01

    Full Text Available This paper presents a MATLAB based user friendly software tool called as PV.MY for optimal sizing of photovoltaic (PV systems. The software has the capabilities of predicting the metrological variables such as solar energy, ambient temperature and wind speed using artificial neural network (ANN, optimizes the PV module/ array tilt angle, optimizes the inverter size and calculate optimal capacities of PV array, battery, wind turbine and diesel generator in hybrid PV systems. The ANN based model for metrological prediction uses four meteorological variables, namely, sun shine ratio, day number and location coordinates. As for PV system sizing, iterative methods are used for determining the optimal sizing of three types of PV systems, which are standalone PV system, hybrid PV/wind system and hybrid PV/diesel generator system. The loss of load probability (LLP technique is used for optimization in which the energy sources capacities are the variables to be optimized considering very low LLP. As for determining the optimal PV panels tilt angle and inverter size, the Liu and Jordan model for solar energy incident on a tilt surface is used in optimizing the monthly tilt angle, while a model for inverter efficiency curve is used in the optimization of inverter size.

  2. Low Voltage Ride-Through Capability of a Single-Stage Single-Phase Photovoltaic System Connected to the Low-Voltage Grid

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede

    2013-01-01

    The progressively growing of single-phase photovoltaic (PV) systems makes the Distribution System Operators (DSO) to update or revise the existing grid codes in order to guarantee the availability, quality and reliability of the electrical system. It is expected that the future PV systems connected...... to the low-voltage grid will be more active with functionalities of low voltage ride-through (LVRT) and the grid support capability, which is not the case today. In this paper, the operation principle is demonstrated for a single-phase grid-connected PV system in low voltage ride through operation in order...... to map future challenges. The system is verified by simulations and experiments. Test results show that the proposed power control method is effective and the single-phase PV inverters connected to low-voltage networks are ready to provide grid support and ride-through voltage fault capability...

  3. Robust PV Degradation Methodology and Application

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, Dirk [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Deline, Christopher A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Kurtz, Sarah [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Kimball, Greg [SunPower; Anderson, Mike [SunPower

    2017-11-15

    The degradation rate plays an important role in predicting and assessing the long-term energy generation of PV systems. Many methods have been proposed for extracting the degradation rate from operational data of PV systems, but most of the published approaches are susceptible to bias due to inverter clipping, module soiling, temporary outages, seasonality, and sensor degradation. In this manuscript, we propose a methodology for determining PV degradation leveraging available modeled clear-sky irradiance data rather than site sensor data, and a robust year-over-year (YOY) rate calculation. We show the method to provide reliable degradation rate estimates even in the case of sensor drift, data shifts, and soiling. Compared with alternate methods, we demonstrate that the proposed method delivers the lowest uncertainty in degradation rate estimates for a fleet of 486 PV systems.

  4. Multilevel Inverter by Cascading Industrial VSI

    DEFF Research Database (Denmark)

    Teodorescu, Remus; Blaabjerg, Frede; Pedersen, John Kim

    2002-01-01

    In this paper the modularity concept applied to medium-voltage adjustable speed drives is addressed. First, the single-phase cascaded voltage-source inverter that uses series connection of IGBT H-bridge modules with isolated dc-buses is presented. Next, a novel three-phase cascaded voltage......-source inverter that uses three IGBT triphase inverter modules along with an output transformer to obtain a 3 p.u. multilevel output voltage is introduced. The system yields in high-quality multistep voltage with up to 4 levels and low dv/dt, balanced operation of the inverter modules, each supplying a third...... of the motor rated kVA. The concept of using cascaded inverters is further extended to a new modular motor-modular inverter system where the motor winding connections are reconnected into several three-phase groups, either six-lead or 12-lead connection according to the voltage level, each powered...

  5. The world PV market 2000: shifting from subsidy to 'fully economic'?

    International Nuclear Information System (INIS)

    Maycock, Paul

    2000-01-01

    This article presents an overview of the world grid-connected photovoltaic (PV) market concentrating on the US, Japan and Germany. The PV markets in the three countries are examined, and PV module shipments, the economics of residential PVs in the markets, and forecasts of the grid-connected market are discussed. Details are given of the German 100,000 roofs PV roof subsidy programme to stimulate the residential and commercial grid-connected market. A summary of the grid-connected PV markets in the three countries, and economic information on German grid-connected PV roofs are tabulated

  6. Modeling of Step-up Grid-Connected Photovoltaic Systems for Control Purposes

    Directory of Open Access Journals (Sweden)

    Daniel Gonzalez

    2012-06-01

    Full Text Available This paper presents modeling approaches for step-up grid-connected photovoltaic systems intended to provide analytical tools for control design. The first approach is based on a voltage source representation of the bulk capacitor interacting with the grid-connected inverter, which is a common model for large DC buses and closed-loop inverters. The second approach considers the inverter of a double-stage PV system as a Norton equivalent, which is widely accepted for open-loop inverters. In addition, the paper considers both ideal and realistic models for the DC/DC converter that interacts with the PV module, providing four mathematical models to cover a wide range of applications. The models are expressed in state space representation to simplify its use in analysis and control design, and also to be easily implemented in simulation software, e.g., Matlab. The PV system was analyzed to demonstrate the non-minimum phase condition for all the models, which is an important aspect to select the control technique. Moreover, the system observability and controllability were studied to define design criteria. Finally, the analytical results are illustrated by means of detailed simulations, and the paper results are validated in an experimental test bench.

  7. Design of an Internal Model Control strategy for single-phase grid-connected PWM inverters and its performance analysis with a non-linear local load and weak grid.

    Science.gov (United States)

    Chaves, Eric N; Coelho, Ernane A A; Carvalho, Henrique T M; Freitas, Luiz C G; Júnior, João B V; Freitas, Luiz C

    2016-09-01

    This paper presents the design of a controller based on Internal Model Control (IMC) applied to a grid-connected single-phase PWM inverter. The mathematical modeling of the inverter and the LCL output filter, used to project the 1-DOF IMC controller, is presented and the decoupling of grid voltage by a Feedforward strategy is analyzed. A Proportional - Resonant Controller (P+Res) was used for the control of the same plant in the running of experimental results, thus moving towards the discussion of differences regarding IMC and P+Res performances, which arrived at the evaluation of the proposed control strategy. The results are presented for typical conditions, for weak-grid and for non-linear local load, in order to verify the behavior of the controller against such situations. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  8. Building integrated multi PV/T/A solar system

    International Nuclear Information System (INIS)

    Ami Elazari

    2000-01-01

    Previous development in solar energy for residential applications proved that there is merit in further development and improvement of combined electricity and hot water and hot air collectors. The justification stems from the fact that waste heat is generated when PV cells are producing electricity but it decrease its efficiency dramatically, and any effective way to cool the cells can improve their efficiency and long while the heat that generated from this cooling process could be stored and used as standard solar hot water/air system. The core unit comprises of integrated PV cells mounted on a flat-plate collector for water and air, hot water storage tank hot air inlet pips to the house electric battery bank, inverter, connecting cables and controller. Double-glazing serving as solar trap to triple the amount of sun ray reaching the PV cells and other technical innovation make the system more cost effective and cost benefit for stand alone and grid connected domestic application. Two way interconnection with the electric grid like in all the roof top program may bring it to economic viability by selling excess electricity during the costly peak hours while buying low cost electricity during the night off-peak hours, and free electricity from the sun plus free hot water and hot air for domestic use as by-product. A basic domestic two-collector system may deliver up to 4 kWh of electricity and 12000 kcal of hot water and air daily. Some 22 systems are currently operating at various locations in Israel, some for 8 years with very good results. (Author)

  9. Evaluation of Energy Production and Energy Yield Assessment Based on Feasibility, Design, and Execution of 3 × 50 MW Grid-Connected Solar PV Pilot Project in Nooriabad

    Directory of Open Access Journals (Sweden)

    Irfan Jamil

    2017-01-01

    Full Text Available The installation of 3 × 50 MW (150 MW DC large utility scale solar power plant is ground based using ventilated polycrystalline module technology with fixed tilt angle of 28° in a 750-acre land, and the site is located about 115 km northeast of Karachi, Pakistan, near the town of ThanoBula Khan, Nooriabad, Sindh. This plant will be connected to the utility distribution system through a national grid of 220 kV outgoing double-loop transmission line. The 3 × 50 MW solar PV will be one of the largest tied grid-connected power projects as the site is receiving a rich average solar radiation of 158.7 kW/h/m2/month and an annual average temperature of about of 27°C. The analysis highlights the preliminary design of the case project such as feasibility study and PV solar design aspects and is based on a simulation study of energy yield assessment which has all been illustrated. The annual energy production and energy yield assessment values of the plant are computed using the PVSYST software. The assumptions and results of energy losses, annual performance ratio (PR 74.73%, annual capacity factor 17.7%, and annual energy production of the plant at 232,518 MWh/year are recorded accordingly. Bear in mind that reference recorded data indicates a good agreement over the performance of the proposed PV power plant.

  10. On the Impact of Partial Shading on PV Output Power

    DEFF Research Database (Denmark)

    Sera, Dezso; Baghzouz, Yahia

    2008-01-01

    clarifies the mechanism of partial PV shading on a number of PV cells connected in series and/or parallel with and without bypass diodes. The analysis is presented in simple terms and can be useful to someone who wishes to determine the impact of some shading geometry on a PV system. The analysis...... is illustrated by measurements on a commercial 70 W panel, and a 14.4 kW PV array....

  11. Power Quality Improvement Utilizing Photovoltaic Generation Connected to a Weak Grid

    Energy Technology Data Exchange (ETDEWEB)

    Muljadi, Eduard [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Tumbelaka, Hanny H. [Petra Christian University; Gao, Wenzhong [UNiversity of Denver

    2017-11-07

    Microgrid research and development in the past decades have been one of the most popular topics. Similarly, the photovoltaic generation has been surging among renewable generation in the past few years, thanks to the availability, affordability, technology maturity of the PV panels and the PV inverter in the general market. Unfortunately, quite often, the PV installations are connected to weak grids and may have been considered as the culprit of poor power quality affecting other loads in particular sensitive loads connected to the same point of common coupling (PCC). This paper is intended to demystify the renewable generation, and turns the negative perception into positive revelation of the superiority of PV generation to the power quality improvement in a microgrid system. The main objective of this work is to develop a control method for the PV inverter so that the power quality at the PCC will be improved under various disturbances. The method is to control the reactive current based on utilizing the grid current to counteract the negative impact of the disturbances. The proposed control method is verified in PSIM platform. Promising results have been obtained.

  12. REVIEW ON GRID INTERFACING OF MULTIMEGAWATT PHOTOVOLTAIC INVERTERS

    OpenAIRE

    Mr. Vilas S. Solanke*; Mr. Naveen Kumar

    2016-01-01

    This paper presents review on the latest development of control of grid connected photovoltaic energy conversion system. Also this paper present existing systems control algorithm for three-phase and single phase grid-connected photovoltaic (PV) system. This paper focuses on one aspect of solar energy, namely grid interfacing of large-scale PV farms. This Grid-connected photovoltaic i.e. PV systems can provide a number of benefits to electric utilities, such as power loss reduction, improve...

  13. The PV market - Past, present, and future

    International Nuclear Information System (INIS)

    Hammond, B.

    1992-01-01

    This paper forecasts the photovoltaic (PV) market growth for the 1900's. Ten years of PV history are reviewed and used to establish market trends in terms of average selling price (ASP) and kilowatts shipped by market segment. The market is segmented into indoor consumer, stand-alone, and grid-connected applications. Indoor consumer presently represents a saturated market and is fairly predictable. The stand-alone market (i.e. not connected to the utility grid) is fairly stable and predictable. The utility PV market, however, is highly dependent on a number of market factors such as the cost of conventional energy, the cost of PV systems, utility acceptance of PV, and regulatory controls. Government and institutional regulations, environmental issues, OPEC and Middle East politics will have the greatest impact on the cost of conventional fuels. Private and federal investment in PV technology development could have a significant impact on the cost of PV systems. Forecasts are provided through the year 2000 for indoor consumer, stand-alone, and utility markets. PV has unique attributes which make it a desirable source of energy in specific applications. It is a renewable source of energy, non-polluting, very reliable, predictable, low maintenance, modular, and has a very low operating cost. The energy source (sunlight) is distributed around the globe. Its limitations are high initial cost, no inherent energy storage, and low energy density

  14. Addressing firefighter safety around solar PV systems

    Energy Technology Data Exchange (ETDEWEB)

    Harris, B. [Sustainable Energy Technologies, Calgary, AB (Canada)

    2010-11-15

    The article discussed new considerations for installing photovoltaic (PV) systems that address the needs of fire service personnel. The presence of a PV system presents a multitude of dangers for firefighters, including electrical shock, the inhalation of toxic gases from being unable to cut a hole through the roof, falling debris and flying glass, and dead loading on a compromised structure and tripping on conduits. Mapping systems should be modified so that buildings with PV systems are identified for first responders, including firefighters who should learn that solar modules present an electrical hazard during the day but not at night; covering PV modules with foam or salvage covers may not shut the system down to a safe level; it takes a few moments for the power in PV modules to reduce to zero; and PV modules or conduit should never be cut, broke, chopped, or walked upon. The California Department of Forestry and Fire Protection recommends creating pathways and allowing easier access to the roof by setting the modules back from roof edges, creating a structurally sound pathway for firefighters to walk on and space to cut ventilation holes. However, the setback rule makes the economics of solar installation less viable for residential applications. The technological innovations aimed at addressing system safety all focus on limiting firefighter contact with live electrical components to within the extra-low-voltage (ELV) band. Some of the inverters on the market that support ELV system architecture were described. 1 fig.

  15. Design and Control of an Inverter for Photovoltaic Applications

    OpenAIRE

    Kjær, Søren Bækhøj

    2005-01-01

    The energy demand in the world is steadily increasing and new types of energy sources must be found in order to cover the future demands, since the conventional sources are about to be emptied. One type of renewable energy source is the photovoltaic (PV) cell, which converts sunlight to electrical current, without any form for mechanical or thermal interlink. PV cells are usually connected together to make PV modules, consisting of 72 PV cells, which generates a DC voltage between 23 Volt to ...

  16. Harmonics Suppression for Single-Phase Grid-Connected Photovoltaic Systems in Different Operation Modes

    DEFF Research Database (Denmark)

    Yang, Yongheng; Zhou, Keliang; Blaabjerg, Frede

    2013-01-01

    -connected PV inverters may be severely affected in different operation modes. In this paper, a detailed analysis is conducted to reveal the relationship between the harmonics level with the power factor and the current level in the PV systems. A current control solution which employs an Internal Model...... Principle (IMP) is proposed to suppress the harmonic currents injected into the grid. Experiments are carried out to verify the analysis and the performance of the proposed control method. It is demonstrated that the proposed method presents an effective solution to harmonics suppression for single......-phase grid-connected PV systems in different operation modes. Especially, it can remove higher order harmonics effectively leading to a better power quality compared to the Proportional plus Multi-Resonant Controller, and it has less computational burden....

  17. PV Systems Reliability Final Technical Report.

    Energy Technology Data Exchange (ETDEWEB)

    Lavrova, Olga [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Flicker, Jack David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Johnson, Jay [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Armijo, Kenneth Miguel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gonzalez, Sigifredo [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Schindelholz, Eric John [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sorensen, Neil R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Yang, Benjamin Bing-Yeh [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-12-01

    The continued exponential growth of photovoltaic technologies paves a path to a solar-powered world, but requires continued progress toward low-cost, high-reliability, high-performance photovoltaic (PV) systems. High reliability is an essential element in achieving low-cost solar electricity by reducing operation and maintenance (O&M) costs and extending system lifetime and availability, but these attributes are difficult to verify at the time of installation. Utilities, financiers, homeowners, and planners are demanding this information in order to evaluate their financial risk as a prerequisite to large investments. Reliability research and development (R&D) is needed to build market confidence by improving product reliability and by improving predictions of system availability, O&M cost, and lifetime. This project is focused on understanding, predicting, and improving the reliability of PV systems. The two areas being pursued include PV arc-fault and ground fault issues, and inverter reliability.

  18. Experimental evaluation of 8 kW grid-connected photovoltaic system in Egypt

    Directory of Open Access Journals (Sweden)

    A. Elkholy

    2016-09-01

    Full Text Available An experimental observation study of 8 kW grid-connected photovoltaic (PV system that is installed at Electronics Research Institute (ERI, Giza, Egypt (Latitude 30.04°N, Longitude 31.21°E, is presented. This study includes the quality of the electrical power generated and injected into the network. The considered system consists of 28 × 295 Wp multicrystalline PV modules, StecaGrid three-phase 8 kW grid-connected inverter and a Solar-Log 300 PM+ for data acquisition and remote monitoring. The power quality parameters at the inverter output side have been measured using CA8335 power quality analyzer. The system has been installed in August 2014 and generated 5.7 MWh till February 2015. The produced electricity by the system is injected directly into the grid without storage device. The purpose of this paper is to present and evaluate the measurements of the power quality parameters obtained from the PV site. Also, this paper presents a comprehensive evaluation of the performance of the system over a period of one week. The observation and analyses exploitation of the collected data can help to evaluate the performance of the PV system connected to the network.

  19. Learning in PV trends and future prospects

    International Nuclear Information System (INIS)

    Schaeffer, G.J.; De Moor, H.H.C.

    2004-06-01

    For large scale application of PV cost reduction is essential. It is shown in this study that the price evolution is on track and even accelerating the last 15 years. Using an experience curve approach a learning rate of little over 20% was found consistent with other studies. As data were collected for small rooftop grid connected systems, it could be shown that this learning rate is not only found for modules, but also for BOS (all costs apart from the modules) in Germany as well as in the Netherlands. Projections of the future price of PV systems show that a learning rate of at least 20% is needed to make introduction of PV affordable. It is very effective to invest in learning, thus increasing the learning rate, as well as developing market segments were the value of PV is higher, such as residential PV systems in southern Europe

  20. Low Voltage Ride-Through of Two-Stage Grid-Connected Photovoltaic Systems Through the Inherent Linear Power-Voltage Characteristic

    DEFF Research Database (Denmark)

    Yang, Yongheng; Sangwongwanich, Ariya; Liu, Hongpeng

    2017-01-01

    In this paper, a cost-effective control scheme for two-stage grid-connected PhotoVoltaic (PV) systems in Low Voltage Ride-Through (LVRT) operation is proposed. In the case of LVRT, the active power injection by PV panels should be limited to prevent from inverter over-current and also energy...... aggregation at the dc-link, which will challenge the dc-link capacitor lifetime if remains uncontrolled. At the same time, reactive currents should be injected upon any demand imposed by the system operators. In the proposed scheme, the two objectives can be feasibly achieved. The active power is regulated...... point tracking controller without significant hardware or software modifications. In this way, the PV system will not operate at the maximum power point, whereas the inverter will not face any over-current challenge but can provide reactive power support in response to the grid voltage fault...

  1. Long term testing and evaluation of PV modules with and without Sunarc antireflective coating of the cover glass

    DEFF Research Database (Denmark)

    Perers, Bengt; Furbo, Simon; Han, Jiangong

    2015-01-01

    Two Photovoltaic (PV) modules have been manufactured by Swemodule. One with Sunarc antireflective coated glass and one without glass surface treatment. The modules have been tested at DTU during 16 months under realistic outdoor conditions. Exactly the same polycrystalline cells were used...... in the modules. No cleaning of the glass has been made except for removal of bird droppings and leaves on single cells that could give a very wrong comparison. The PV modules were mounted due south at 45 degree tilt angle. They were connected to the electric grid with small 250W module inverters from Involar...... that also realized the MPP tracking to give the maximum output of each module. The electric power output was measured both on the AC and DC side and with different measurement equipment to be sure about the accuracy in improvement. The results indicate a potential long term improvement in a system from 3...

  2. Effective switching frequency multiplier inverter

    Science.gov (United States)

    Su, Gui-Jia [Oak Ridge, TN; Peng, Fang Z [Okemos, MI

    2007-08-07

    A switching frequency multiplier inverter for low inductance machines that uses parallel connection of switches and each switch is independently controlled according to a pulse width modulation scheme. The effective switching frequency is multiplied by the number of switches connected in parallel while each individual switch operates within its limit of switching frequency. This technique can also be used for other power converters such as DC/DC, AC/DC converters.

  3. Development of a software application to evaluate the performance and energy losses of grid-connected photovoltaic systems

    International Nuclear Information System (INIS)

    Trillo-Montero, D.; Santiago, I.; Luna-Rodriguez, J.J.; Real-Calvo, R.

    2014-01-01

    Highlights: • Software application to perform an automated analysis of grid-connected PV systems. • It integrates data from all devices registering data on typical PV installations. • Flexible to analyze installations with different configurations and components. • An analysis of two grid-connected PV systems located in Andalusia, was performed. • Temperature losses in summer months varying between 15% and 25% of energy production. - Abstract: The aim of this paper was to design and develop a software application that enables users to perform an automated analysis of data from the monitoring of grid-connected photovoltaic (PV) systems. This application integrates data from all devices already in operation such as environmental sensors, inverters and meters, which record information on typical PV installations. This required the development of a Relational Database Management System (RDBMS), consisting of a series of linked databases, enabling all PV system information to be stored; and a software, called S·lar, which enables all information from the monitoring to be automatically migrated to the database as well as determining some standard magnitudes related to performances and losses of PV installation components at different time scales. A visualization tool, which is both graphical and numerical, makes access to all of the information be a simple task. Moreover, the application enables relationships between parameters and/or magnitudes to be easily established. Furthermore, it can perform a preliminary analysis of the influence of PV installations on the distribution grids where the produced electricity is injected. The operation of such a software application was implemented by performing the analysis of two grid-connected PV installations located in Andalusia, Spain, via data monitoring therein. The monitoring took place from January 2011 to May 2012

  4. Control and performance analysis of grid connected photovoltaic systems of two different technologies in a desert environment

    Directory of Open Access Journals (Sweden)

    Layachi ZAGHBA

    2017-12-01

    Full Text Available In this study, is to investigate the effect of real climatic conditions on the performance parameters of a 9 kWp grid connected photovoltaic plant during one-year using typical days installed in the desert environment in south of Algeria (Ghardaia site. The PV plant contain the following components: solar PV array, with a DC/DC boost converter, neural MPPT, that allow maximal power conversion into the grid, have been included. These methods can extract maximum power from each of the independent PV arrays connected to DC link voltage level, a DC/AC inverter and a PI current control system. The PV array is divides in two parallel PV technology types; the first includes 100 PV modules mono-crystalline silicon (mc-Si arranged in 20 parallel groups of 5 modules in series, and the second of composed of 24 amorphous modules (Inventux X series, arranged in 6 parallel groups of 4 modules in series. The proposed system tested using MATLAB/SIMULINK platform in which a maximum power tracked under constant and real varying solar irradiance. The study concluded that output power and energy from two PV technology types (mc-Si and Amorphous-Si increases linearly with increase of solar irradiance.

  5. Long term performance analysis of a grid connected photovoltaic system in Northern Ireland

    International Nuclear Information System (INIS)

    Mondol, Jayanta Deb; Yohanis, Yigzaw; Smyth, Mervyn; Norton, Brian

    2006-01-01

    The performance of a 13 kW p roof mounted, grid connected photovoltaic system in Northern Ireland over a period of three years has been analysed on hourly, daily and monthly bases. The derived parameters included reference yield, array yield, final yield, array capture losses, system losses, PV and inverter efficiencies and performance ratio. The effects of insolation and inverter operation on the system performance were investigated. The monthly average daily PV, system and inverter efficiencies varied from 4.5% to 9.2%, 3.6% to 7.8% and 50% to 87%, respectively. The annual average PV, system and inverter efficiencies were 7.6%, 6.4% and 75%, respectively. The monthly average daily DC and AC performance ratios ranged from 0.35 to 0.74 and 0.29 to 0.66, respectively. The annual average monthly AC performance ratios for the three years were 0.60, 0.61 and 0.62, respectively. The performance of this system is compared with that of other representative systems internationally

  6. Solar PV. Innovators talking; Zon PV. Innovators aan het woord

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-02-15

    Qualitative studies have been conducted of the results of completed projects focused on energy innovation, spread over the seven themes of the top sector Energy: Energy saving in industry, Energy conservation in the built environment, Gas, Bio-energy, Smart grids, Offshore Wind, Solar PV. This provides insight into the follow-up activities and lessons of some EOS (Energy Research Subsidy) completed projects with the aim to inspire, connect and strengthen the TKIs (Topconsortia for Knowledge and Innovation) and individual companies and researchers working on energy innovation. This report concerns the research on solar PV [Dutch] Er is een kwalitatief onderzoek uitgevoerd naar de resultaten van afgeronde projecten gericht op energie-innovatie, verdeeld over de zeven thema's van de topsector Energie: Energiebesparing in de industrie; Energiebesparing in de gebouwde omgeving; Gas; Bio-energie; Smart grids; Wind op zee; Zon-pv. Daarmee wordt inzicht gegeven in de vervolgactiviteiten en lessen van een aantal afgesloten EOS-projecten (Energie Onderzoek Subsidie) met het oog op het inspireren, verbinden en versterken van de TKI's (Topconsortia voor Kennis en Innovatie) en individuele bedrijven en onderzoekers die werken aan energie-innovatie. Dit rapport betreft het onderzoek naar zon PV.

  7. Solar PV. Innovators talking; Zon PV. Innovators aan het woord

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-02-15

    Qualitative studies have been conducted of the results of completed projects focused on energy innovation, spread over the seven themes of the top sector Energy: Energy saving in industry, Energy conservation in the built environment, Gas, Bio-energy, Smart grids, Offshore Wind, Solar PV. This provides insight into the follow-up activities and lessons of some EOS (Energy Research Subsidy) completed projects with the aim to inspire, connect and strengthen the TKIs (Topconsortia for Knowledge and Innovation) and individual companies and researchers working on energy innovation. This report concerns the research on solar PV [Dutch] Er is een kwalitatief onderzoek uitgevoerd naar de resultaten van afgeronde projecten gericht op energie-innovatie, verdeeld over de zeven thema's van de topsector Energie: Energiebesparing in de industrie; Energiebesparing in de gebouwde omgeving; Gas; Bio-energie; Smart grids; Wind op zee; Zon-pv. Daarmee wordt inzicht gegeven in de vervolgactiviteiten en lessen van een aantal afgesloten EOS-projecten (Energie Onderzoek Subsidie) met het oog op het inspireren, verbinden en versterken van de TKI's (Topconsortia voor Kennis en Innovatie) en individuele bedrijven en onderzoekers die werken aan energie-innovatie. Dit rapport betreft het onderzoek naar zon PV.

  8. Building Integrated PV and PV/Hybrid Products - The PV:BONUS Experience: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, H.; Pierce, L. K.

    2001-10-01

    Presented at the 2001 NCPV Program Review Meeting: Successes and lessons learned from PV:BONUS (Building Opportunities in the United States in PV). This program has funded the development of PV or PV/hybrid products for building applications.

  9. Design and implementation of a new modified sliding mode controller for grid-connected inverter to controlling the voltage and frequency.

    Science.gov (United States)

    Ghanbarian, Mohammad Mehdi; Nayeripour, Majid; Rajaei, Amirhossein; Mansouri, Mohammad Mahdi

    2016-03-01

    As the output power of a microgrid with renewable energy sources should be regulated based on the grid conditions, using robust controllers to share and balance the power in order to regulate the voltage and frequency of microgrid is critical. Therefore a proper control system is necessary for updating the reference signals and determining the proportion of each inverter in the microgrid control. This paper proposes a new adaptive method which is robust while the conditions are changing. This controller is based on a modified sliding mode controller which provides adapting conditions in linear and nonlinear loads. The performance of the proposed method is validated by representing the simulation results and experimental lab results. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  10. Inverter for Interchangeable Use as Current Source Inverter and Voltage Source Inverter for Interconnecting to Grid

    Science.gov (United States)

    Teruya, Daisuke; Masukawa, Shigeo; Iida, Shoji

    We propose a novel inverter that can be operated either as a Current Source Inverter (CSI) or as a Voltage Source Inverter (VSI) by changing only the control signals. It is proper to apply it to the interconnecting system with renewal energy, such as photovoltaic cells or wind generation systems, to a grid. This inverter is usually operated as the CSI connected to the grid. Even if the energy source has a lower voltage than the grid, the energy can be supplied to the grid through the proposed inverter. The power factor can be briefly maintained at almost unity. When power supply from the grid is interrupted, the proposed circuit should be operated as the VSI in the stand-alone operation mode. In this way, the circuit can maintain a constant output voltage to the loads. In this paper, the proposed circuit configuration and the control schemes for both the CSI and the VSI are described. Further, the circuit characteristics for both are discussed experimentally.

  11. Comprehensive synchronous reference frame discrete-time modelling of a grid-connected PV for fast DC-side voltage control

    NARCIS (Netherlands)

    Almeida, P.M.; Barbosa, P.G.; Duarte, J.L.; Ribeiro, P.F.

    2017-01-01

    This paper presents a novel comprehensive discrete-time model of a three-phase single stage grid-connected photovoltaic generation system. The detailed model is carried out on synchronous reference frame. It is shown that both converter's AC and DC-side discrete time model differs from the

  12. Adaptive Reactive Power Control of PV Power Plants for Improved Power Transfer Capability under Ultra-Weak Grid Conditions

    DEFF Research Database (Denmark)

    Yang, Dongsheng; Wang, Xiongfei; Liu, Fangcheng

    2018-01-01

    with the unity power factor. Then, considering the reactive power compensation from PV inverters, the minimum SCR in respect to Power Factor (PF) is derived, and the optimized coordination of the active and reactive power is exploited. It is revealed that the power transfer capability of PV power plant under...... of a 200 MW PV power plant demonstrate that the proposed method can ensure the rated power transfer of PV power plant with the SCR of 1.25, provided that the PV inverters are operated with the minimal PF=0.9.......This paper analyzes the power transfer limitation of the PV power plant under the ultra-weak grid condition, i.e., when the Short-Circuit Ratio (SCR) is close to 1. It explicitly identifies that a minimum SCR of 2 is required for the PV power plant to deliver the rated active power when operating...

  13. The market for photovoltaic (PV) technology

    International Nuclear Information System (INIS)

    Frantzis, L.; Vejtasa, K.M.

    1993-01-01

    This paper describes a study that was intended to provide the Electric Power Research Institute (EPRI) with a market analysis for photovoltaic (PV) technologies under development by EPRI and others. The analysis was to focus on markets and factors leading to significant incremental growth for PV demand, large enough to support more efficient scale PV manufacturing capacity. EPRI anticipates that PV ultimately could provide grid-connected power, however, the 1995--2010 market dynamics are uncertain. The specific objectives of this study, therefore, were to: determine what major future domestic US markets for PV technologies will emerge and provide enough volume to support significant improvements in manufacturing costs through manufacturing economies of scale; provide insight on what is needed to gain acceptance of PV technologies for electric power generation in those major markets; provide insight on when investments in demonstration and manufacturing facilities should be made and what is needed to be successful in each element of the business that these markets could support (e.g., technology development, manufacturing, sales, installation, and service); and provide key insights on the requirements for commercial success of PV in the utility sector

  14. Optimization of a single stage inverter with one cycle control for photovoltaic power generation

    Energy Technology Data Exchange (ETDEWEB)

    Egiziano, L.; Femia, N.; Granozio, D.; Petrone, G.; Spagnuolo, G. [Salermo Univ., Salermo (Italy); Vitelli, M. [Seconda Univ. di Napoli, Napoli (Italy)

    2006-07-01

    An optimized one-cycle control (OCC) for maximum power point tracking and power factor correction in grid-connected photovoltaic (PV) applications was described. OCC is a nonlinear control technique that rejects line perturbations and allows both output power factor co-reaction and tracking of input PV fields. An OCC system was analyzed in order to select optimal design parameters. Parameters were refined through the selection of suitable design constraints. A stochastic search was then performed. Criteria were then developed to distinguish appropriate design parameters for the optimized OCC. The optimization was based on advanced heuristic techniques for non-linear constrained optimization. Performance indices were calculated for each feasible set of parameters. A customized perturb and observe control was then applied to the single-stage inverter. Results of the optimization process were validated by a series of time-domain simulations conducted under heavy, varying irradiance conditions. Results of the simulations showed that the optimized controllers showed improved performance in terms of power drawn from the PV field. 7 refs., 1 tab., 5 figs.

  15. Implementation of fuzzy-sliding mode based control of a grid connected photovoltaic system.

    Science.gov (United States)

    Menadi, Abdelkrim; Abdeddaim, Sabrina; Ghamri, Ahmed; Betka, Achour

    2015-09-01

    The present work describes an optimal operation of a small scale photovoltaic system connected to a micro-grid, based on both sliding mode and fuzzy logic control. Real time implementation is done through a dSPACE 1104 single board, controlling a boost chopper on the PV array side and a voltage source inverter (VSI) on the grid side. The sliding mode controller tracks permanently the maximum power of the PV array regardless of atmospheric condition variations, while The fuzzy logic controller (FLC) regulates the DC-link voltage, and ensures via current control of the VSI a quasi-total transit of the extracted PV power to the grid under a unity power factor operation. Simulation results, carried out via Matlab-Simulink package were approved through experiment, showing the effectiveness of the proposed control techniques. Copyright © 2015. Published by Elsevier Ltd.

  16. Research on Experiment of Islanding Protection Device of Grid-connected Photovoltaic System Based on RTDS

    Science.gov (United States)

    Zhou, Ning; Yang, Jia; Cheng, Zheng; Chen, Bo; Su, Yong Chun; Shu, Zhan; Zou, Jin

    2017-06-01

    Solar photovoltaic power generation is the power generation using solar cell module converting sunlight into DC electric energy. In the paper an equivalent model of solar photovoltaic power generation system is built in RTDS. The main circuit structure of the two-stage PV grid-connected system consists of the DC-DC, DC-AC circuit. The MPPT (Maximum Power Point Tracking) control of the PV array is controlled by adjusting the duty ratio of the DC-DC circuit. The proposed control strategy of constant voltage/constant reactive power (V/Q) control is successfully implemented grid-connected control of the inverter when grid-connected operation. The closed-loop experiment of islanding protection device of photovoltaic power plant on RTDS, verifies the correctness of the simulation model, and the experimental verification can be applied to this type of device.

  17. A Simulation of Energy Storage System for Improving the Power System Stability with Grid-Connected PV using MCA Analysis and LabVIEW Tool

    Directory of Open Access Journals (Sweden)

    Jindrich Stuchly

    2015-01-01

    Full Text Available The large-scale penetration of distributed, Renewable power plants require transfers of large amounts of energy. This, in turn, puts a high strain on the energy delivery infrastructure. In particular, photovoltaic power plants supply energy with high intermittency, possibly affecting the stability of the grid by changing the voltage at the plant connection point. In this contribution, we summarize the main negative effects of selected and real-operated grid connected photovoltaic plant. Thereafter a review of suitable Energy storage systems to mitigate the negative effects has been carried out, compared and evaluated using Multi-criterion analysis. Based on this analysis, data collected at the plant and the grid, are used to design the energy storage systems to support connection of the plant to the grid. The cooperation of these systems is then analysed and evaluated using simulation tools created in LabVIEW for this purpose. The simulation results demonstrate the capability of energy storage system solutions to significantly reduce the negative feedback effects of Photovoltaic Power Plan to the low voltage grid.

  18. PV-hybrid and mini-grid

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-07-01

    Within the 5th European PV-hybrid and mini-grid conference 29th and 30th April, 2010 in Tarragona (Spain) the following lectures were held: (1) Overview of IEA PVPS Task 11 PV-hybrid systems within mini grids; (2) Photovoltaic revolution for deployment in developing countries; (3) Legal and financial conditions for the sustainable operation of mini-grids; (4) EU instruments to promote renewable energies in developing countries; (5) PV hybridization of diesel electricity generators: Conditions of profitability and examples in differential power and storage size ranges; (6) Education suit of designing PV hybrid systems; (7) Sustainable renewable energy projects for intelligent rural electrification in Laos, Cambodia and Vietnam; (8) Techno-economic feasibility of energy supply of remote villages in Palestine by PV systems, diesel generators and electric grid (Case studies: Emnazeil and Atouf villages); (9) Technical, economical and sustainability considerations of a solar PV mini grid as a tool for rural electrification in Uganda; (10) Can we rate inverters for rural electrification on the basis of energy efficiency?; (11) Test procedures for MPPT charge controllers characterization; (12) Energy storage for mini-grid stabilization; (13) Redox flow batteries - Already an alternative storage solution for hybrid PV mini-grids?; (14) Control methods for PV hybrid mini-grids; (15) Partial AC-coupling in mini-grids; (15) Normative issues of small wind turbines in PV hybrid systems; (16) Communication solutions for PV hybrid systems; (17) Towards flexible control and communication of mini-grids; (18) PV/methanol fuel cell hybrid system for powering a highway security variable message board; (19) Polygeneration smartgrids: A solution for the supply of electricity, potable water and hydrogen as fuel for transportation in remote Areas; (20) Implementation of the Bronsbergen micro grid using FACDS; (21) A revisited approach for the design of PV wind hybrid systems; (22

  19. Impedance estimation of photovoltaic modules for inverter start-up ...

    Indian Academy of Sciences (India)

    Pallavi Bharadwaj

    The analysis of this paper can be used to estimate the expected peak inrush current in PV inverters. ..... scenario a mechanical switch makes and breaks the contact, .... Therefore even though the ratio of the peak to the steady current is lower ...

  20. Building brighter PV business

    International Nuclear Information System (INIS)

    Hacker, R.

    2002-01-01

    The current status and future prospects of the UK market for solar photovoltaic (PV) electricity are briefly discussed. Through the Department of Trade and Industry (DTI), the UK Government has supported research and development (R and D) into PV for a number of years. This programme has now been extended to demonstrating PV systems on houses. Phase 2 - the domestic field trial programme - aims to monitor the performance of individual systems and the impact on a cluster of systems on the electricity network. New funding had allowed a trebling of the size of this programme, which involves both private developers and housing associations. The DTI is also working to promote PV on commercial buildings, eg the installation of BP Solar PV systems at BP petrol stations. The PV industry in the UK is technically strong and is working to overcome the barriers in the UK to greater uptake of the technology (including cost, conservatism, legal requirements and metering practices). Improvements are expected in a number of recent initiatives in the electricity industry to boost PV use and the PV industry is lobbying for PV to be included in the Enhanced Capital Allowances (ECA) scheme