Bidirectional converter interface for a battery energy storage test bench

DEFF Research Database (Denmark)

Trintis, Ionut; Thomas, Stephan; Blank, Tobias

2011-01-01

This paper presents the bidirectional converter interface for a 6 kV battery energy storage test bench. The power electronic interface consists a two stage converter topology having a low voltage dc-ac grid connected converter and a new dual active bridge dc-dc converter with high transformation...

Power Electronics Converters for Wind Turbine Systems

DEFF Research Database (Denmark)

Blaabjerg, Frede; Liserre, Marco; Ma, Ke

2012-01-01

The steady growth of installed wind power together with the upscaling of the single wind turbine power capability has pushed the research and development of power converters toward full-scale power conversion, lowered cost pr kW, increased power density, and also the need for higher reliability. ...

Power electronics converters for wind turbine systems

DEFF Research Database (Denmark)

Blaabjerg, Frede; Liserre, Marco; Ma, Ke

2011-01-01

The steady growth of installed wind power which reached 200 GW capacity in 2010, together with the up-scaling of the single wind turbine power capability - 7 MW’s has been announced by manufacturers - has pushed the research and development of power converters towards full scale power conversion,...

Lifetime estimation for the power semiconductors considering mission profiles in wind power converter

DEFF Research Database (Denmark)

Ma, Ke; Liserre, Marco; Blaabjerg, Frede

2013-01-01

for the reliability improvement and also for cost reduction of wind power technology. Unfortunately, the existing lifetime estimation methods for the power electronic converter are not yet suitable in the wind power application, because the comprehensive mission profiles are not well specified and included......As a key component in the wind turbine system, power electronic converter and its power semiconductors suffer from adverse power loadings related to environment, and are proven to have certain failure rates. Therefore, correct lifetime estimation of wind power converter is crucial...... estimation, more detailed information for the reliability performance of wind power converter can be obtained....

A current controlled matrix converter for wind energy conversion systems based on permanent magnet synchronous generator

Directory of Open Access Journals (Sweden)

Naggar H. Saad

2016-05-01

Full Text Available The main challenges of wind energy conversion systems (WECS are to maximize the energy capture from the wind and injecting reactive power during the fault. This paper presents a current controlled matrix converter to interface Permanent Magnet Synchronous Generators (PMSG based WECS with the grid. To achieve fast dynamic response with reduced current ripples, a hysteresis current control is utilized. The proposed control system decouples the active and reactive components of the PMSG current to extract the maximum power from the wind at a given wind velocity and to inject reactive power to the grid. Reactive power injection during the fault satisfying the grid-codes requirement. The proposed WECS has been modeled and simulated using PSCAD/EMTDC software package.

Efficiency and reliability improvement in wind turbine converters by grid converter adaptive control

DEFF Research Database (Denmark)

Trintis, Ionut; Munk-Nielsen, Stig; Abrahamsen, Flemming

2013-01-01

This paper presents a control method that reduces the losses in wind turbine converters adaptively controlling the grid converter. The dc-link voltage adapts its reference based on the system state and therefore reduces the stored energy, and is therefore kept at the minimum necessary for the grid...... and generator side. Operating in this way, the electrical and thermal stress factors are decreased on the power electronic devices, increasing their lifetime. The simulation results using this method show efficiency increase and devices temperature cycles slightly decreased. Experimental results on a wind...... turbine power stack shows efficiency increase in the high power region....

A Multi-Functional Power Electronic Converter in Distributed Generation Power Systems

DEFF Research Database (Denmark)

Chen, Zhe; Blaabjerg, Frede; Pedersen, John Kim

2005-01-01

of the converter interfacing a wind power generation unit is also given. The power electronic interface performs the optimal operation in the wind turbine system to extract the maximum wind power, while it also plays a key role in a hybrid compensation system that consists of the active power electronic converter......This paper presents a power electronic converter which is used as an interface for a distributed generation unit/energy storage device, and also functioned as an active power compensator in a hybrid compensation system. The operation and control of the converter have been described. An example...... and passive filters connected to each distorting load or distributed generation (DG) unit. The passive filters are distributely located to remove major harmonics and provide reactive power compensation. The active power electronic filter corrects the system unbalance, removes the remaining harmonic components...

Grid converters for photovoltaic and wind power systems

CERN Document Server

Teodorescu, Remus; Rodríguez, Pedro

2011-01-01

"Grid Converters for Photovoltaic and Wind Power Systems provides a comprehensive description of the control of grid converters for photovoltaic and wind power systems. The authors present a range of control methods for meeting the latest application, power quality and power conversion requirements and standards, as well as looking towards potential future control functions. Practical examples, exercises, and an accompanying website with simulation models using Matlab and Simulink environments, and PSIM software make this text a pragmatic resource for electrical engineers as well as students taking related courses"--

Lifetime estimation for the power semiconductors considering mission profiles in wind power converter

OpenAIRE

Ma, Ke; Liserre, Marco; Blaabjerg, Frede

2013-01-01

As a key component in the wind turbine system, power electronic converter and its power semiconductors suffer from adverse power loadings related to environment, and are proven to have certain failure rates. Therefore, correct lifetime estimation of wind power converter is crucial for the reliability improvement and also for cost reduction of wind power technology. Unfortunately, the existing lifetime estimation methods for the power electronic converter are not yet suitable in the wind power...

A New Fault Diagnosis Algorithm for PMSG Wind Turbine Power Converters under Variable Wind Speed Conditions

Directory of Open Access Journals (Sweden)

Yingning Qiu

2016-07-01

Full Text Available Although Permanent Magnet Synchronous Generator (PMSG wind turbines (WTs mitigate gearbox impacts, they requires high reliability of generators and converters. Statistical analysis shows that the failure rate of direct-drive PMSG wind turbines’ generators and inverters are high. Intelligent fault diagnosis algorithms to detect inverters faults is a premise for the condition monitoring system aimed at improving wind turbines’ reliability and availability. The influences of random wind speed and diversified control strategies lead to challenges for developing intelligent fault diagnosis algorithms for converters. This paper studies open-circuit fault features of wind turbine converters in variable wind speed situations through systematic simulation and experiment. A new fault diagnosis algorithm named Wind Speed Based Normalized Current Trajectory is proposed and used to accurately detect and locate faulted IGBT in the circuit arms. It is compared to direct current monitoring and current vector trajectory pattern approaches. The results show that the proposed method has advantages in the accuracy of fault diagnosis and has superior anti-noise capability in variable wind speed situations. The impact of the control strategy is also identified. Experimental results demonstrate its applicability on practical WT condition monitoring system which is used to improve wind turbine reliability and reduce their maintenance cost.

Two Level Versus Matrix Converters Performance in Wind Energy Conversion Systems Employing DFIG

Science.gov (United States)

Reddy, Gongati Pandu Ranga; Kumar, M. Vijaya

2017-10-01

Wind power capacity has received enormous growth during past decades. With substantial development of wind power, it is expected to provide a fifth of world's electricity by the end of 2030. In wind energy conversion system, the power electronic converters play an important role. This paper presents the two level and matrix converters performance in wind energy conversion system employing Doubly Fed Induction Generator (DFIG). The DFIG is a wound rotor induction generator. Because of the advantages of the DFIG over other generators it is being used for most of the wind applications. This paper also discusses control of converters using the space vector pulse width modulation technique. The MATLAB/SIMULINK ® software is used to study the performance of the converters.

Reliability and Energy Loss in Full-scale Wind Power Converter Considering Grid Codes and Wind Classes

DEFF Research Database (Denmark)

Zhou, Dao; Blaabjerg, Frede; Franke, Toke

2014-01-01

With the increasing penetration of the wind power, reliable operation and cost-effective wind energy production are of more and more importance. As one of the promising configurations, the cost on reliability and production losses of permanent-magnet synchronous generator based full-scale wind......, if the specific designed wind turbine system operates at different wind classes, it can be seen that higher wind class level results in lower lifetime of the power converter. In respect to the cost of the reactive power, either the OE or the UE reactive power increases the energy loss per year significantly...... power converter is studied considering the grid code with reactive power production as well as the annual wind profile. Regarding the reliability, it is found that either the Over-Excited (OE) or the Under-Excited (UE) reactive power injection threatens the lifespan under all wind classes. Meanwhile...

Wind-driven SEIG supplying DC microgrid through a single-stage power converter

Directory of Open Access Journals (Sweden)

Vellapatchi Nayanar

2016-09-01

Full Text Available Nowadays, there is an increased emphasis on utilizing the renewable energy sources and selection of suitable power converters for supplying dc microgrid. Among the various renewable energy sources, wind energy stands first in terms of installed capacity. So, an attempt is made in this paper for supplying dc microgrid utilizing wind energy. A self-excited induction generator has been used in the proposed wind energy conversion system (WECS. A single-stage power converter, namely, semi-converter is connected between the SEIG and dc grid terminals for closed-loop control of the proposed system. A perturb and observe (P&O based maximum power point tracking (MPPT algorithm has been developed and implemented using a dsPIC30F4011 digital controller. In this MPPT algorithm, the firing angle of the converter is adjusted by continuously monitoring the dc grid current for a given wind velocity. For analyzing the proposed system, a MATLAB/Simulink model has been developed by selecting the various components starting from wind-turbine model to the power converter supplying dc microgrid. Successful working of the proposed WECS has also been shown through experimental results obtained on a prototype model developed in the laboratory.

Design of power converter in DFIG wind turbine with enhanced system-level reliability

DEFF Research Database (Denmark)

Zhou, Dao; Zhang, Guanguan; Blaabjerg, Frede

2017-01-01

With the increasing penetration of wind power, reliable and cost-effective wind energy production are of more and more importance. As one of the promising configurations, the doubly-fed induction generator based partial-scale wind power converter is still dominating in the existing wind farms...... margin. It can be seen that the B1 lifetime of the grid-side converter and the rotor-side converter deviates a lot by considering the electrical stresses, while they become more balanced by using an optimized reliable design. The system-level lifetime significantly increases with an appropriate design...

Comparison of multi-MW converters considering the determining factors in wind power application

DEFF Research Database (Denmark)

Ma, Ke; Liserre, Marco; Blaabjerg, Frede

2013-01-01

converters are normally targeted to the industrial drive applications, and they did not take into account the special requirements in the case of wind power. This paper tries to unify and compare several promising wind power converters by a series new model and perspective. The evaluation criteria...... will mainly focus on the costeffectiveness of power semiconductors and the converter performances when complying with grid codes - which are more crucial for the wind power converters. It is concluded that the power converters with various voltage levels, topologies, and paralleling structures are possible...... to be unified for comparison. And the two-level low-voltage converter solution still shows cost advantage regarding power semiconductors, while some multi-level medium-voltage converter solutions can show better performance when complying with the grid codes....

Modular Multilevel Converters Based Variable Speed Wind Turbines for Grid Faults

DEFF Research Database (Denmark)

Deng, Fujin; Liu, Dong; Wang, Yanbo

2016-01-01

in the dc-link of the power converter to improve system performance, but also ensure the grid-side current balancing to increase the generated power of the wind turbine under the unbalanced grid fault, in comparison with the conventional VSWT based on BTB three-level NPC converters. The simulation studies......The modular multilevel converter (MMC) becomes attractive in the medium- and high-power application with high modularity. In this paper, the MMC is proposed to be applied in the variable speed wind turbine (VSWT) based on the full-scale back-to-back (BTB) power converter, where the generator...

Modularized multilevel and z-source power converter as renewable energy interface for vehicle and grid-connected applications

Science.gov (United States)

Cao, Dong

Due the energy crisis and increased oil price, renewable energy sources such as photovoltaic panel, wind turbine, or thermoelectric generation module, are used more and more widely for vehicle and grid-connected applications. However, the output of these renewable energy sources varies according to different solar radiation, wind speed, or temperature difference, a power converter interface is required for the vehicle or grid-connected applications. Thermoelectric generation (TEG) module as a renewable energy source for automotive industry is becoming very popular recently. Because of the inherent characteristics of TEG modules, a low input voltage, high input current and high voltage gain dc-dc converters are needed for the automotive load. Traditional high voltage gain dc-dc converters are not suitable for automotive application in terms of size and high temperature operation. Switched-capacitor dc-dc converters have to be used for this application. However, high voltage spike and EMI problems exist in traditional switched-capacitor dc-dc converters. Huge capacitor banks have to be utilized to reduce the voltage ripple and achieve high efficiency. A series of zero current switching (ZCS) or zero voltage switching switched-capacitor dc-dc converters have been proposed to overcome the aforementioned problems of the traditional switched-capacitor dc-dc converters. By using the proposed soft-switching strategy, high voltage spike is reduced, high EMI noise is restricted, and the huge capacitor bank is eliminated. High efficiency, high power density and high temperature switched-capacitor dc-dc converters could be made for the TEG interface in vehicle applications. Several prototypes have been made to validate the proposed circuit and confirm the circuit operation. In order to apply PV panel for grid-connected application, a low cost dc-ac inverter interface is required. From the use of transformer and safety concern, two different solutions can be implemented, non

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...

Thermal analysis of two-level wind power converter under symmetrical grid fault

DEFF Research Database (Denmark)

Zhou, Dao; Blaabjerg, Frede

2013-01-01

In this paper, the case of symmetrical grid fault when using the multi-MW wind turbine of partial-scale and full-scale two-level power converter are designed and investigated. Firstly, the different operation behaviors of the relevant power converters under the voltage dip will be described......) condition as well as the junction temperature. For the full-scale wind turbine system, the most thermal stressed power device in the grid-side converter will appear at the grid voltage below 0.5 pu, and for the partial-scale wind turbine system, the most thermal stressed power device in the rotor...

Solar wind stream interfaces

International Nuclear Information System (INIS)

Gosling, J.T.; Asbridge, J.R.; Bame, S.J.; Feldman, W.C.

1978-01-01

Measurements aboard Imp 6, 7, and 8 reveal that approximately one third of all high-speed solar wind streams observed at 1 AU contain a sharp boundary (of thickness less than approx.4 x 10 4 km) near their leading edge, called a stream interface, which separates plasma of distinctly different properties and origins. Identified as discontinuities across which the density drops abruptly, the proton temperature increases abruptly, and the speed rises, stream interfaces are remarkably similar in character from one stream to the next. A superposed epoch analysis of plasma data has been performed for 23 discontinuous stream interfaces observed during the interval March 1971 through August 1974. Among the results of this analysis are the following: (1) a stream interface separates what was originally thick (i.e., dense) slow gas from what was originally thin (i.e., rare) fast gas; (2) the interface is the site of a discontinuous shear in the solar wind flow in a frame of reference corotating with the sun; (3) stream interfaces occur at speeds less than 450 km s - 1 and close to or at the maximum of the pressure ridge at the leading edges of high-speed streams; (4) a discontinuous rise by approx.40% in electron temperature occurs at the interface; and (5) discontinuous changes (usually rises) in alpha particle abundance and flow speed relative to the protons occur at the interface. Stream interfaces do not generally recur on successive solar rotations, even though the streams in which they are embedded often do. At distances beyond several astronomical units, stream interfaces should be bounded by forward-reverse shock pairs; three of four reverse shocks observed at 1 AU during 1971--1974 were preceded within approx.1 day by stream interfaces. Our observations suggest that many streams close to the sun are bounded on all sides by large radial velocity shears separating rapidly expanding plasma from more slowly expanding plasma

Design of a DC-AC Link Converter for 500W Residential Wind Generator

Directory of Open Access Journals (Sweden)

Riza Muhida

2012-12-01

Full Text Available  As one of alternative sources of renewable energy, wind energy has an excellence prospect in Indonesia, particularly in coastal and hilly areas which have potential wind to generate electricity for residential uses. There is urgent need to locally develop low cost inverter of wind generator system for residential use. Recent developments in power electronic converters and embedded computing allow improvement of power electronic converter devices that enable integration of microcontrollers in its design. In this project, an inverter circuit with suitable control scheme design was developed. The circuit was to be used with a selected topology of Wind Energy Conversion System (WECS to convert electricity generated by a 500W direct-drive permanent magnet type wind generator which is typical for residential use. From single phase AC output of the generator, a rectifier circuit is designed to convert AC to DC voltage. Then a DC-DC boost converter is used to step up the voltage to a nominal DC voltage suitable for domestic use. The proposed inverter then will convert the DC voltage to sinusoidal AC. The duty cycle of sinusoidal Pulse-Width Modulated (SPWM signal controlling switches in the inverter was generated by a microcontroller. The lab-scale experimental rig involves simulation of wind generator by running a geared DC motor coupled with 500W wind generator where the prototype circuit was connected at the generator output. The experimental circuit produced single phase 240V sinusoidal AC voltage with frequency of 50Hz. Measured total harmonics distortion (THD of the voltage across load was 4.0% which is within the limit of 5% as recommended by IEEE Standard 519-1992.

Thermal loading and reliability of 10 MW multilevel wind power converter at different wind roughness classes

DEFF Research Database (Denmark)

Isidori, Andrea; Rossi, Fabio Mario; Blaabjerg, Frede

2012-01-01

This paper focuses on the design, thermal loading and reliability of a three-level Neutral Point Clamped (3-L NPC) back-to-back full scale converter for a 10 MW direct-drive wind turbine equipped with a Permanent Magnet Synchronous Generator (PMSG). The reliability performance of the three......-level converter is strongly influenced by the thermal behaviour of the semiconductor devices and their mission profile which directly affects the lifetime and the cost of the whole converter. Therefore, the simulation platform is developed in Matlab/Simulink and PLECS simulation environment to analyse...... the dynamics of the system using different kinds of modulation strategies and analyzing different wind load conditions dependent on roughness classes. It is concluded that 60° discontinuous PWM modulation strategies show better thermal performance and increase the estimated lifetime of the converter...

Thermal Loading and Lifetime Estimation for Power Device Considering Mission Profiles in Wind Power Converter

DEFF Research Database (Denmark)

Ma, Ke; Liserre, Marco; Blaabjerg, Frede

2015-01-01

for the reliability improvement and also for cost reduction of wind power technology. Unfortunately, the existing lifetime estimation methods for the power electronic converter are not yet suitable in the wind power application, because the comprehensive mission profiles are not well specified and included......As a key component in the wind turbine system, the power electronic converter and its power semiconductors suffer from complicated power loadings related to environment, and are proven to have high failure rates. Therefore, correct lifetime estimation of wind power converter is crucial...... devices, more detailed information of the lifetime-related performance in wind power converter can be obtained. Some experimental results are also included to validate the thermal behavior of power device under different mission profiles....

Soft switching bidirectional DC-DC converter for ultracapacitor-batteries interface

International Nuclear Information System (INIS)

Adib, Ehsan; Farzanehfard, Hosein

2009-01-01

In this paper a new soft switching bidirectional DC-DC converter is introduced which can be applied as the interface circuit between ultracapacitors and batteries or fuel cells. All semiconductor devices in the proposed converter are soft switched while the control circuit remains PWM. Due to achieved soft switching condition, the energy conversion through the proposed converter is highly efficient. The proposed converter is analyzed and a prototype converter is implemented. The presented experimental results confirm the theoretical analysis.

Control and operation of wind turbine converters during faults in an offshore wind power plant grid with VSC-HVDC connection

DEFF Research Database (Denmark)

Chaudhary, Sanjay; Teodorescu, Remus; Rodriguez, Pedro

2011-01-01

Voltage source converter (VSC) based high voltage dc (HVDC) transmission is an attractive technique for large offshore wind power plants, especially when long cable transmission is required for connection to the onshore grid. New multi-MW wind turbines are likely to be equipped with full scale...... converters to meet the stringent grid code requirements. In such a scenario, the offshore grid is terminated to the power electronic converters on all the ends. This paper presents a control scheme for the synchronization and control of the grid side converters (GSC) of the wind turbine generators (WTG......). Current limit control enables the GSC to sustain the fault currents during short circuits in the offshore wind collector system grid. However, power transmission is affected, and the fault has to be isolated. It can be resynchronized after the fault has been cleared and the breaker reclosed. Healthy WTG...

The Electrostatic Wind Energy Converter : Electrical performance of a high voltage prototype

NARCIS (Netherlands)

Djairam, D.

2008-01-01

Wind energy is converted to electrical energy by letting the wind move charged particles against the direction of an electric field. The advantage of this type of conversion is that no rotational movement, which occurs in conventional wind turbines, is required. An electrostatic wind energy

Design, operation and control of series-connected power converters for offshore wind parks

Energy Technology Data Exchange (ETDEWEB)

Ruiz, Alejandro Garces

2012-07-01

Offshore wind farms need to develop technologies that fulfill three main objectives:Efficiency, power density and reliability. The purpose of this thesis is to study an HVDC transmission system based on series connection of the turbines which theoretically meet these three objectives. A new topology of matrix converter operated at high frequency is proposed. This converter is studied using different modulation algorithms. Simulation and experimental results demonstrated that the converter can be operated as a current source converter with high efficiency. An optimal control based on a linear quadratic regulator is propose dto control the matrix converter as well as the converter placed on shore. Results demonstrated the high performance of this type of control and its simplicity for implementation. An stationary state study based on non-linear programming and Montecarlo simulation was carried out to determine the performance of the concept for long-term operation. Series connection is an efficient technology if and only if the differences in the effective wind velocity are small. This aspect limits the number of wind turbines that can be connected in series, since a numerous number of turbines will lead to high covariances in the distribution of the wind. A complementary study about active filter and reactive power compensation was carried out using an optimization-based algorithm. (Author)

Simulation of wind power with front-end converter into interconnected grid system

Directory of Open Access Journals (Sweden)

Sharad W. Mohod

2009-09-01

Full Text Available In the growing electricity supply industry and open access market for electricity worldwide, renewable sources are getting added into the grid system. This affects the grid power quality. To assess the impact on grid due to wind energy integration, the knowledge of electrical characteristic of wind turbine and associated control equipments are required. The paper presents a simulation set-up for wind turbine in MATLAB / SIMULINK, with front end converter and interconnected system. The presented control scheme provides the wind power flow to the grid through a converter. The injected power in the system at the point of common coupling is ensured within the power quality norms.

Soft switching bidirectional DC-DC converter for ultracapacitor-batteries interface

Energy Technology Data Exchange (ETDEWEB)

Adib, Ehsan; Farzanehfard, Hosein [Dept. of Electrical and Computer Engineering, Isfahan Univ. of Technology (Iran)

2009-12-15

In this paper a new soft switching bidirectional DC-DC converter is introduced which can be applied as the interface circuit between ultracapacitors and batteries or fuel cells. All semiconductor devices in the proposed converter are soft switched while the control circuit remains PWM. Due to achieved soft switching condition, the energy conversion through the proposed converter is highly efficient. The proposed converter is analyzed and a prototype converter is implemented. The presented experimental results confirm the theoretical analysis. (author)

Design of a DC-AC Link Converter for 500W Residential Wind Generator

OpenAIRE

Riza Muhida; Ahmad Firdaus A. Zaidi; Afzeri Tamsir; Rudi Irawan

2012-01-01

 As one of alternative sources of renewable energy, wind energy has an excellence prospect in Indonesia, particularly in coastal and hilly areas which have potential wind to generate electricity for residential uses. There is urgent need to locally develop low cost inverter of wind generator system for residential use. Recent developments in power electronic converters and embedded computing allow improvement of power electronic converter devices that enable integration of microcontrollers in...

Grid Converters for Photovoltaic and Wind Power Systems

DEFF Research Database (Denmark)

Teodorescu, Remus; Liserre, Marco; Rodriguez, Pedro

power, operation within a wide range of voltage and frequency, voltage ride-through capability, reactive current injection during faults, grid services support. This book explains the topologies, modulation and control of grid converters for both photovoltaic and wind power applications. In addition...... to power electronics, this book focuses on the specific applications in photovoltaic wind power systems where grid condition is an essential factor. With a review of the most recent grid requirements for photovoltaic and wind power systems, the book discusses these other relevant issues: Modern grid...... inverter topologies for photovoltaic and wind turbines Islanding detection methods for photovoltaic systems Synchronization techniques based on second order generalized integrators (SOGI) Advanced synchronization techniques with robust operation under grid unbalance condition grid filter design and active...

Thermal Loading and Reliability of 10 MW Multilevel Wind Power Converter at Different Wind Roughness Classes

DEFF Research Database (Denmark)

Isidori, Andrea; Rossi, Fabio Mario; Blaabjerg, Frede

2014-01-01

This paper focuses on the design, thermal loading, and reliability of a three-level neutral-point-clamped back-to-back full-scale converter for a 10-MW direct-drive wind turbine equipped with a permanent-magnet synchronous generator. The reliability performance of the three-level converter...... is strongly influenced by the thermal behavior of the semiconductor devices and their mission profile which directly affects the lifetime and the cost of the entire converter. Therefore, a simulation platform is developed in a Matlab/Simulink and PLECS simulation environment to analyze the dynamics...... of the system using different kinds of modulation strategies and analyzing the different wind-load conditions that are dependent on roughness classes. This paper shows that the 60 ° discontinuous pulsewidth-modulation strategies allow better thermal performance and increase the estimated lifetime...

Design of a high power, resonant converter for DC wind turbines

DEFF Research Database (Denmark)

Dincan, Catalin Gabriel; Kjær, Philip Carne; Chen, Yu-Hsing

2018-01-01

This paper presents a design procedure and loss estimation for a high power, medium voltage series resonant converter (entitled SRC#), intended for application in megawatt medium-voltage DC wind turbines. The converter is operated with a novel method of operation, entitled pulse removal technique...

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.

Reconfiguring grid-interfacing converters for power quality improvement

NARCIS (Netherlands)

Wang, F.; Duarte, J.L.; Hendrix, M.A.M.; Encica, L.; Gysen, B.L.J.; Jansen, J.W.; Krop, D.C.J.

2008-01-01

In this paper reconfiguration of grid-interfacing converters is proposed for power quality improvement. In addition to the traditional function of delivering energy between distributed sources and the utility grid, more flexible ancillary functions can be integrated into the control of

The APA Style Converter: a Web-based interface for converting articles to APA style for publication.

Science.gov (United States)

Li, Ping; Cunningham, Krystal

2005-05-01

The APA Style Converter is a Web-based tool with which authors may prepare their articles in APA style according to the APA Publication Manual (5th ed.). The Converter provides a user-friendly interface that allows authors to copy and paste text and upload figures through the Web, and it automatically converts all texts, references, and figures to a structured article in APA style. The output is saved in PDF or RTF format, ready for either electronic submission or hardcopy printing.

Maximum generation power evaluation of variable frequency offshore wind farms when connected to a single power converter

Energy Technology Data Exchange (ETDEWEB)

Gomis-Bellmunt, Oriol; Sumper, Andreas [Centre d' Innovacio Tecnologica en Convertidors Estatics i Accionaments (CITCEA-UPC), Universitat Politecnica de Catalunya UPC, Av. Diagonal, 647, Pl. 2, 08028 Barcelona (Spain); IREC Catalonia Institute for Energy Research, Barcelona (Spain); Junyent-Ferre, Adria; Galceran-Arellano, Samuel [Centre d' Innovacio Tecnologica en Convertidors Estatics i Accionaments (CITCEA-UPC), Universitat Politecnica de Catalunya UPC, Av. Diagonal, 647, Pl. 2, 08028 Barcelona (Spain)

2010-10-15

The paper deals with the evaluation of power generated by variable and constant frequency offshore wind farms connected to a single large power converter. A methodology to analyze different wind speed scenarios and system electrical frequencies is presented and applied to a case study, where it is shown that the variable frequency wind farm concept (VF) with a single power converter obtains 92% of the total available power, obtained with individual power converters in each wind turbine (PC). The PC scheme needs multiple power converters implying drawbacks in terms of cost, maintenance and reliability. The VF scheme is also compared to a constant frequency scheme CF, and it is shown that a significant power increase of more than 20% can be obtained with VF. The case study considers a wind farm composed of four wind turbines based on synchronous generators. (author)

Power electronic solutions for interfacing offshore wind turbine generators to medium voltage DC collection grids

Science.gov (United States)

Daniel, Michael T.

Here in the early 21st century humanity is continuing to seek improved quality of life for citizens throughout the world. This global advancement is providing more people than ever with access to state-of-the-art services in areas such as transportation, entertainment, computing, communication, and so on. Providing these services to an ever-growing population while considering the constraints levied by continuing climate change will require new frontiers of clean energy to be developed. At the time of this writing, offshore wind has been proven as both a politically and economically agreeable source of clean, sustainable energy by northern European nations with many wind farms deployed in the North, Baltic, and Irish Seas. Modern offshore wind farms are equipped with an electrical system within the farm itself to aggregate the energy from all turbines in the farm before it is transmitted to shore. This collection grid is traditionally a 3-phase medium voltage alternating current (MVAC) system. Due to reactive power and other practical constraints, it is preferable to use a medium voltage direct current (MVDC) collection grid when siting farms >150 km from shore. To date, no offshore wind farm features an MVDC collection grid. However, MVDC collection grids are expected to be deployed with future offshore wind farms as they are sited further out to sea. In this work it is assumed that many future offshore wind farms may utilize an MVDC collection grid to aggregate electrical energy generated by individual wind turbines. As such, this work presents both per-phase and per-pole power electronic converter systems suitable for interfacing individual wind turbines to such an MVDC collection grid. Both interfaces are shown to provide high input power factor at the wind turbine while providing DC output current to the MVDC grid. Common mode voltage stress and circulating currents are investigated, and mitigation strategies are provided for both interfaces. A power sharing

Ancillary Frequency Control of Direct Drive Full-Scale Converter Based Wind Power Plants

DEFF Research Database (Denmark)

Hu, Weihao; Su, Chi; Fang, Jiakun

2013-01-01

This paper presents a simulation model of a wind power plant based on a MW-level variable speed wind turbine with a full-scale back-to-back power converter developed in the simulation tool of DIgSILENT Power Factory. Three different kinds of ancillary frequency control strategies, namely inertia...... control strategies are effective means for providing ancillary frequency control of variable speed wind turbines with full-scale back-to-back power converters....... emulation, primary frequency control and secondary frequency control, are proposed in order to improve the frequency stability of power systems. The modified IEEE 39-bus test system with a large-scale wind power penetration is chosen as the studied power system. Simulation results show that the proposed...

A model for the origin of solar wind stream interfaces

International Nuclear Information System (INIS)

Hundhausen, A.J.; Burlaga, L.F.

1975-01-01

The basic variations in solar wind properties that have been observed at 'stream interfaces' near 1 AU are explained by a gas dynamic model in which a radially propagating stream, produced by a temperature variation in the solar envelope, steepens nonlinearly while moving through interplanetary space. The region thus identified with the stream interface separates the ambient solar wind from the fresh hot material originally in the stream. However, the interface regions given by the present model are thicker than most stream interfaces observed in the solar wind, a fact suggesting that some additional physical process may be important in determining that thickness. Variations in the density, speed, or Alfven pressure alone appear not to produce streams with such an interface

HVDC Solution for Offshore Wind Park Comprising Turbines Equipped with Full-Range Converters

DEFF Research Database (Denmark)

Sharma, Ranjan; Rasmussen, Tonny Wederberg; Jensen, Kim Høj

2010-01-01

a voltage drop is created at the collection grid, the wind turbines go into fault-ride-through mode. The power output from each of the wind turbines is thus reduced to balance the system power. The detailed explanation of the strategy is presented in the paper. Matlab simulation model was prepared and some...... of a HVDC transmission system. The power system under study includes an offshore wind farm comprising turbines equipped with full range converters. The collection network is a local AC grid. Power transmission is done through HVDC system. The grid side VSC (voltage source converter) controls the DC voltage...

Converters for Distributed Power Generation Systems

DEFF Research Database (Denmark)

Blaabjerg, Frede; Yang, Yongheng

2015-01-01

Power electronics technology has become the enabling technology for the integration of distributed power generation systems (DPGS) such as offshore wind turbine power systems and commercial photovoltaic power plants. Depending on the applications, a vast array of DPGS-based power converter...... topologies has been developed and more are coming into the market in order to achieve an efficient and reliable power conversion from the renewables. In addition, stringent demands from both the distribution system operators and the consumers have been imposed on the renewable-based DPGS. This article...... presents an overview of the power converters for the DPGS, mainly based on wind turbine systems and photovoltaic systems, covering a wide range of applications. Moreover, the modulation schemes and interfacing power filters for the power converters are also exemplified. Finally, the general control...

Comparison of Interleaved Boost Converter Configurations for Solar Photovoltaic System Interface

Directory of Open Access Journals (Sweden)

R Ramaprabha

2013-12-01

Full Text Available Solar photovoltaic (SPV panels that convert light energy into electrical energy through the photovoltaic effect have nonlinear internal resistance. Hence, with the variation in the intensity of light falling on the panel, the internal resistance varies. For effective utilization of the SPV panel, it is necessary to extract the maximum power from it. For maximum power extraction from SPV panels, DC-DC converter interface is used. The problem in using high frequency converter interface is the resultant high frequency ripple interaction with the SPV system. In this work, an interleaved boost converter (IBC is considered to reduce the ripple. Our finding is that IBC fed by a SPV panel reduces this ripple to a greater extent. IBC also has a faster transient response as compared to conventional boost converters with reduced ripple contents. The main aim of this paper is to present a comparative analysis of the performance of IBC with inductors that are coupled in different ways. The results of the simulation were extrapolated with the help of MATLAB software and verified through experimentation.

Power converter topologies for wind energy conversion systems: Integrated modeling, control strategy and performance simulation

Energy Technology Data Exchange (ETDEWEB)

Melicio, R.; Catalao, J.P.S. [Department of Electromechanical Engineering, University of Beira Interior, R. Fonte do Lameiro, 6201-001 Covilha (Portugal); Mendes, V.M.F. [Department of Electrical Engineering and Automation, Instituto Superior de Engenharia de Lisboa, R. Conselheiro Emidio Navarro, 1950-062 Lisbon (Portugal)

2010-10-15

This paper presents new integrated model for variable-speed wind energy conversion systems, considering a more accurate dynamic of the wind turbine, rotor, generator, power converter and filter. Pulse width modulation by space vector modulation associated with sliding mode is used for controlling the power converters. Also, power factor control is introduced at the output of the power converters. Comprehensive performance simulation studies are carried out with matrix, two-level and multilevel power converter topologies in order to adequately assert the system performance. Conclusions are duly drawn. (author)

Advanced Control Strategy of Back-to-Back PWM Converters in PMSG Wind Power System

Directory of Open Access Journals (Sweden)

Tan Luong Van

2015-01-01

Full Text Available This paper proposes a control scheme of back-to-back PWM converters for the permanent magnet synchronous generator (PMSG wind turbine system. The DC-link voltage can be controlled at the machine-side converter (MSC, while the grid-side converter (GSC controls the grid active power for a maximum power point tracking (MPPT. At the grid fault condition, the DC-link voltage controller is designed using a feedback linearization (FL theory. For the MPPT, a proportional control loop is added to the torque control to reduce the influence of the inertia moment in the wind turbines, which can improve its dynamic performance. The validity of this control algorithm has been verified by the simulation of the 2-MW PMSG wind turbine system.

Fractional-order control and simulation of wind energy systems with PMSG/full-power converter topology

International Nuclear Information System (INIS)

Melicio, R.; Mendes, V.M.F.; Catalao, J.P.S.

2010-01-01

This paper presents a new integrated model for the simulation of wind energy systems. The proposed model is more realistic and accurate, considering a variable-speed wind turbine, two-mass rotor, permanent magnet synchronous generator (PMSG), different power converter topologies, and filters. Additionally, a new control strategy is proposed for the variable-speed operation of wind turbines with PMSG/full-power converter topology, based on fractional-order controllers. Comprehensive simulation studies are carried out with matrix and multilevel power converter topologies, in order to adequately assert the system performance in what regards the quality of the energy injected into the electric grid. Finally, conclusions are duly drawn.

Fractional-order control and simulation of wind energy systems with PMSG/full-power converter topology

Energy Technology Data Exchange (ETDEWEB)

Melicio, R.; Catalao, J.P.S. [Department of Electromechanical Engineering, University of Beira Interior, R. Fonte do Lameiro, 6201-001 Covilha (Portugal); Mendes, V.M.F. [Department of Electrical Engineering and Automation, Instituto Superior de Engenharia de Lisboa, R. Conselheiro Emidio Navarro, 1950-062 Lisbon (Portugal)

2010-06-15

This paper presents a new integrated model for the simulation of wind energy systems. The proposed model is more realistic and accurate, considering a variable-speed wind turbine, two-mass rotor, permanent magnet synchronous generator (PMSG), different power converter topologies, and filters. Additionally, a new control strategy is proposed for the variable-speed operation of wind turbines with PMSG/full-power converter topology, based on fractional-order controllers. Comprehensive simulation studies are carried out with matrix and multilevel power converter topologies, in order to adequately assert the system performance in what regards the quality of the energy injected into the electric grid. Finally, conclusions are duly drawn. (author)

Converter controls and flicker study of PMSG-based grid connected wind turbines

Directory of Open Access Journals (Sweden)

Ali H. Kasem Alaboudy

2013-03-01

Full Text Available With the increased penetration of wind power, the influence of wind turbine generators on the grid power quality stipulates careful investigation and analysis. Direct driven permanent magnet synchronous generator (PMSG with a back-to-back converter set is one of the promising technologies in wind power generation schemes. In this paper, comprehensive models of wind turbine are used to analyze power and voltage fluctuations. The short time flicker index is used to assess the voltage fluctuation emitted. The control scheme of the grid-side converter is supported with a voltage regulation loop to reduce flicker emission. The effects of grid and site parameters on voltage fluctuation are investigated. Simulation results show that reduced flicker emissions are given when the developed voltage regulation loop is activated. Reasonable values of grid and site parameters contribute in the minimization of voltage fluctuation and flicker emission levels.

Multi-Port High Voltage Gain Modular Power Converter for Offshore Wind Farms

Directory of Open Access Journals (Sweden)

Sen Song

2018-06-01

Full Text Available In high voltage direct current (HVDC power transmission of offshore wind power systems, DC/DC converters are applied to transfer power from wind generators to HVDC terminals, and they play a crucial role in providing a high voltage gain, high efficiency, and high fault tolerance. This paper introduces an innovative multi-port DC/DC converter with multiple modules connected in a scalable matrix configuration, presenting an ultra-high voltage step-up ratio and low voltage/current rating of components simultaneously. Additionally, thanks to the adoption of active clamping current-fed push–pull (CFPP converters as sub-modules (SMs, soft-switching is obtained for all power switches, and the currents of series-connected CFPP converters are auto-balanced, which significantly reduce switching losses and control complexity. Furthermore, owing to the expandable matrix structure, the output voltage and power of a modular converter can be controlled by those of a single SM, or by adjusting the column and row numbers of the matrix. High control flexibility improves fault tolerance. Moreover, due to the flexible control, the proposed converter can transfer power directly from multiple ports to HVDC terminals without bus cable. In this paper, the design of the proposed converter is introduced, and its functions are illustrated by simulation results.

The Application of Stationary VOC-PR with PLL for Grid side Converter-based Wind Power Generation System

DEFF Research Database (Denmark)

Guo, Yougui; Zeng, Ping; Li, Lijuan

2010-01-01

Voltage oriented control PR is combined with space vector modulation and phase locked loop to control the grid side converter in wind power generation system in this paper. First the mathematical models of grid side converter and LCL filter as well as grid are given. Then the control strategy...... of grid side converter-based wind power generation system is given in detail. Finally the simulation model consisting of the grid side converter wind power generation system is set up. The simulation results have verified that the control strategy is feasible to be used for control of gird currents......, active power, reactive power and DC-link voltage in wind power generation system. It has laid a good basis for the real system development....

Application of Boost Converter to Increase the Speed Range of Dual-stator Winding Induction Generator in Wind Power Systems

DEFF Research Database (Denmark)

Kavousi, Ayoub; Fathi, S. Hamid; Milimonfared, Jafar

2018-01-01

In this paper, a topology using a Dual-stator Winding Induction Generator (DWIG) and a boost converter is proposed for the variable speed wind power application. At low rotor speeds, the generator saturation limits the voltage of the DWIG. Using a boost converter, higher DC voltage can be produced...... while the DWIG operates at Maximum Power Point Tracking (MPPT) even at low speed and low voltage conditions. Semiconductor Excitation Controller (SEC) of the DWIG utilizes Control-Winding Voltage Oriented Control (CWVOC) method to adjust the voltage, considering V/f characteristics. For the proposed...... topology, the SEC capacity and the excitation capacitor is optimized by analyzing the SEC reactive current considering wind turbine power-speed curve, V/f strategy, and the generator parameters. The method shows that the per-unit capacity of the SEC can be limited to the inverse of DWIG magnetizing...

Control of improved full-bridge three-level DC/DC converter for wind turbines in a DC grid

DEFF Research Database (Denmark)

Deng, Fujin; Chen, Zhe

2013-01-01

transformer in the IFBTL dc/dc converter. A modulation strategy, including two operation modes, is proposed for the IFBTL dc/dc converter. Then, a voltage balancing control strategy is proposed for the IFBTL dc/dc converter. Furthermore, the control of the wind turbine based on the IFBTL dc/dc converter......This paper presents an improved full-bridge three-level (IFBTL) dc/dc converter for a wind turbine in a dc grid by inserting a passive filter into the dc/dc converter to improve the performance of the converter. The passive filter can effectively reduce the voltage stress of the medium frequency...

Reactive Power Impact on Lifetime Prediction of Two-level Wind Power Converter

DEFF Research Database (Denmark)

Zhou, Dao; Blaabjerg, Frede; Lau, M.

2013-01-01

The influence of reactive power injection on the dominating two-level wind power converter is investigated and compared in terms of power loss and thermal behavior. Then the lifetime of both the partial-scale and full-scale power converter is estimated based on the widely used Coffin-Manson model...

Reliability-cost models for the power switching devices of wind power converters

DEFF Research Database (Denmark)

Ma, Ke; Blaabjerg, Frede

2012-01-01

In order to satisfy the growing reliability requirements for the wind power converters with more cost-effective solution, the target of this paper is to establish a new reliability-cost model which can connect the relationship between reliability performances and corresponding semiconductor cost...... temperature mean value Tm and fluctuation amplitude ΔTj of power devices, are presented. With the proposed reliability-cost model, it is possible to enable future reliability-oriented design of the power switching devices for wind power converters, and also an evaluation benchmark for different wind power...... for power switching devices. First the conduction loss, switching loss as well as thermal impedance models of power switching devices (IGBT module) are related to the semiconductor chip number information respectively. Afterwards simplified analytical solutions, which can directly extract the junction...

Plan for the Brent Spar. Wind and wave energy converter

International Nuclear Information System (INIS)

De Vries, E.

1996-01-01

In a competition on the future of the much discussed oil platform Brent Spar of Shell the idea to retrofit the platform into a combined wind/wave energy converter appears to be an attractive option for Shell

Analysis of Harmonic Coupling and Stability in Back-to-Back Converter Systems for Wind Turbines using Harmonic State Space (HSS)

DEFF Research Database (Denmark)

Kwon, Jun Bum; Wang, Xiongfei; Bak, Claus Leth

2015-01-01

Understanding about harmonic propagation in wind turbine converter is fundamental to research the influence of these on a large network harmonic distortion. Therefore, the analysis of wind turbine converter harmonic spectrum as well as the influence of converter operating point into the network i...... connected into the large wind farm model to analyze the overall steady-state harmonic as well as harmonic stability. All theoretical modeling and analysis is verified by means of simulation and experimental results.......Understanding about harmonic propagation in wind turbine converter is fundamental to research the influence of these on a large network harmonic distortion. Therefore, the analysis of wind turbine converter harmonic spectrum as well as the influence of converter operating point into the network...... is urgently important issues in harmonic studies on wind farm. However, the conventional modeling procedure and simplified model for controller design are not enough to analyze such complicated systems. Besides, they have many limitations in terms of including a non-linear component, different operating...

Effect of full converter wind turbines on inter-area oscillation of power systems

DEFF Research Database (Denmark)

Askari, Hanieh Hajizadeh; Hashemi Toghroljerdi, Seyedmostafa; Eriksson, Robert

2015-01-01

By increasing in the penetration level of wind turbines, the influence of these new added generation units on the power system oscillations specifically inter-area oscillations has to be thoroughly investigated. In this paper, the impact of increasing in the penetration of full rate converter wind...... turbines (FRC-WTs) on the inter-area oscillations of power system is examined. In order to have a comprehensive evaluation of the effects of FRC-WT on the inter-area oscillations, different scenarios associated with the wind power penetration levels, wind farm locations, strength of interconnection line......, and different operating conditions of synchronous generators are investigated. The synchronous generators, exciter systems and power system stabilizers (PSSs) as well as the FRC-WT grid-side converter and its related controllers are modelled in detail in Matlab in order to evaluate the effects of FRC...

Selection of DC/DC converter for offshore wind farms with MVDC power collection

DEFF Research Database (Denmark)

Dincan, Catalin Gabriel; Kjær, Philip Carne; Chen, Yu-Hsing

2017-01-01

Four DC/DC converters are analyzed and compared with respects to availability, efficiency, ratings, repair costs and power density. Intended application is offshore wind farms with MVDC power collection. The selected topology is a new series resonant converter, which offers 99% efficiency across...

Multi-Input Converter with MPPT Feature for Wind-PV Power Generation System

Directory of Open Access Journals (Sweden)

Chih-Lung Shen

2013-01-01

Full Text Available A multi-input converter (MIC to process wind-PV power is proposed, designed, analyzed, simulated, and implemented. The MIC cannot only process solar energy but deal with wind power, of which structure is derived from forward-type DC/DC converter to step-down/up voltage for charger systems, DC distribution applications, or grid connection. The MIC comprises an upper modified double-ended forward, a lower modified double-ended forward, a common output inductor, and a DSP-based system controller. The two modified double-ended forwards can operate individually or simultaneously so as to accommodate the variation of the hybrid renewable energy under different atmospheric conditions. While the MIC operates at interleaving mode, better performance can be achieved and volume also is reduced. The proposed MIC is capable of recycling the energy stored in the leakage inductance and obtaining high step-up output voltage. In order to draw maximum power from wind turbine and PV panel, perturb-and-observe method is adopted to achieve maximum power point tracking (MPPT feature. The MIC is constructed, analyzed, simulated, and tested. Simulations and hardware measurements have demonstrated the feasibility and functionality of the proposed multi-input converter.

Frequency Adaptability of Harmonics Controllers for Grid-Interfaced Converters

DEFF Research Database (Denmark)

Yang, Yongheng; Zhou, Keliang; Blaabjerg, Frede

2017-01-01

sensitivity of the most popular harmonic controllers for grid-interfaced converters. The frequency adaptability of these harmonic controllers is evaluated in the presence of a variable grid frequency within a specified reasonable range, e.g., +-1% of the nominal grid frequency (50 Hz). Solutions...

Maximum power point tracking techniques for wind energy systems using three levels boost converter

Science.gov (United States)

Tran, Cuong Hung; Nollet, Frédéric; Essounbouli, Najib; Hamzaoui, Abdelaziz

2018-05-01

This paper presents modeling and simulation of three level Boost DC-DC converter in Wind Energy Conversion System (WECS). Three-level Boost converter has significant advantage compared to conventional Boost. A maximum power point tracking (MPPT) method for a variable speed wind turbine using permanent magnet synchronous generator (PMSG) is also presented. Simulation of three-level Boost converter topology with Perturb and Observe algorithm and Fuzzy Logic Control is implemented in MATLAB/SIMULINK. Results of this simulation show that the system with MPPT using fuzzy logic controller has better performance to the Perturb and Observe algorithm: fast response under changing conditions and small oscillation.

Analysis of a high power, resonant DC-DC converter for DC wind turbines

DEFF Research Database (Denmark)

Dincan, Catalin Gabriel; Kjær, Philip Carne; Chen, Yu-Hsing

2018-01-01

This paper is introducing a new method of operation for a series resonant converter, with intended application in megawatt high-voltage DC wind turbines. Compared to a frequency controlled series resonant converter operated in sub resonant mode, the method (entitled pulse removal technique) allows...

Medium voltage three-level converters for the grid connection of a multi-MW wind turbine

DEFF Research Database (Denmark)

Senturk, Osman Selcuk; Helle, Lars; Munk-Nielsen, Stig

2009-01-01

Three-level (3L) neutral point clamped (NPC), flying capacitor (FC), and H-bridge (HB) voltage source converters (VSCs) as a grid-side full-scale medium voltage (MV) converter are modeled, controlled, and simulated for the grid connection of a hypothetical 6MW wind turbine. Via the converter...... topological features and the simulation results demonstrating the converter performance, these three 3L-VSCs are discussed and compared in terms of power density and reliability, which can be considered as two of the most important criteria for the converters placed in wind turbine nacelles. Given the grid...... connection circuit (without capacitive switching ripple filters), the 3L-HB-VSC is expected to be superior with respect to power density and reliability over the 3L-NPC- and -FC-VSCs....

Medium Voltage Three-level Converters for the Grid Connection of aMulti-MW Wind Turbine

DEFF Research Database (Denmark)

Senturk, Osman Selcuk; Helle, Lars; Munk-Nielsen, Stig

2009-01-01

Three-level (3L) neutral point clamped (NPC), flying capacitor (FC), and H-bridge (HB) voltage source converters (VSCs) as a grid-side full-scale medium voltage (MV) converter are modeled, controlled, and simulated for the grid connection of a hypothetical 6MW wind turbine. Via the converter...... topological features and the simulation results demonstrating the converter performance, these three 3L-VSCs are discussed and compared in terms of power density and reliability, which can be considered as two of the most important criteria for the converters placed in wind turbine nacelles. Given the grid...... connection circuit (without capacitive switching ripple filters), the 3L-HB-VSC is expected to be superior with respect to power density and reliability over the 3L-NPC- and -FC-VSCs....

Modeling and Simulation of Generator Side Converter of Doubly Fed Induction Generator-Based Wind Power Generation System

DEFF Research Database (Denmark)

Guo, Yougui; Zeng, Ping; Blaabjerg, Frede

2010-01-01

A real wind power generation system is given in this paper. SVM control strategy and vector control is applied for generator side converter and doubly fed induction generator respectively. First the mathematical models of the wind turbine rotor, drive train, generator side converter are described...

Series resonant converter with auxiliary winding turns: analysis, design and implementation

Science.gov (United States)

Lin, Bor-Ren

2018-05-01

Conventional series resonant converters have researched and applied for high-efficiency power units due to the benefit of its low switching losses. The main problems of series resonant converters are wide frequency variation and high circulating current. Thus, resonant converter is limited at narrow input voltage range and large input capacitor is normally adopted in commercial power units to provide the minimum hold-up time requirement when AC power is off. To overcome these problems, the resonant converter with auxiliary secondary windings are presented in this paper to achieve high voltage gain at low input voltage case such as hold-up time duration when utility power is off. Since the high voltage gain is used at low input voltage cased, the frequency variation of the proposed converter compared to the conventional resonant converter is reduced. Compared to conventional resonant converter, the hold-up time in the proposed converter is more than 40ms. The larger magnetising inductance of transformer is used to reduce the circulating current losses. Finally, a laboratory prototype is constructed and experiments are provided to verify the converter performance.

Direct AC–AC grid interface converter for ocean wave energy system

International Nuclear Information System (INIS)

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

2015-01-01

Highlights: • Novel power grid interface converter for ocean wave energy system. • Unlike conventional approach, generator output is directly converted into fixed frequency AC for synchronous connection. • High conversion efficient and power quality could be achieved. - Abstract: Ocean wave energy is very promising. However, existing systems are using rectifying circuits to convert variable voltage and variable frequency output of electric generator into DC voltage and then use grid-tied inverter to connect to the power grid. Such arrangement will not only reduce the overall efficient but also increase the cost of the system. A direct AC–AC converter is a desirable solution. In this paper, a six-switch AC–AC converter has been proposed as a single phase grid-connected interface. New switching scheme has been derived for the converter such that the virtual input AC–DC conversion and the output DC–AC conversion can be decoupled. State-space averaging model and pulse width modulation scheme have been derived for the converter. As the input and the output operations can be decoupled, two independent controllers have been designed to handle the input AC–DC regulation and the output DC–AC regulation. The proposed scheme demands for two separate duty ratios and novel switching scheme has been derived to realize the combined duty ratios in one switching cycle. Power regulation, harmonics elimination and power factor correction control algorithms have also been derived for the converter when it is connected to the supply grid. Experimental results of a small scale model are included to demonstrate the effectiveness of the proposed switching and control schemes

Back-to-back converter control of grid-connected wind turbine to mitigate voltage drop caused by faults

DEFF Research Database (Denmark)

Hassanzadeh, Fattah; Sangrody, Hossein; Hajizadeh, Amin

2017-01-01

Power electronic converters enable wind turbines, operating at variable speed, to generate electricity more efficiently. Among variable speed operating turbine generators, permanent magnetic synchronous generator (PMSG) has got more attentions due to low cost and maintenance requirements...... side converter is designed to improve voltage drop caused by the fault in the grid while maximum available active power of wind turbine system is injected to the grid and the DC link voltage in the converter is regulated. The methodology of the converter control is elaborated in details and its...

Reliability modeling and analysis for a novel design of modular converter system of wind turbines

International Nuclear Information System (INIS)

Zhang, Cai Wen; Zhang, Tieling; Chen, Nan; Jin, Tongdan

2013-01-01

Converters play a vital role in wind turbines. The concept of modularity is gaining in popularity in converter design for modern wind turbines in order to achieve high reliability as well as cost-effectiveness. In this study, we are concerned with a novel topology of modular converter invented by Hjort, Modular converter system with interchangeable converter modules. World Intellectual Property Organization, Pub. No. WO29027520 A2; 5 March 2009, in this architecture, the converter comprises a number of identical and interchangeable basic modules. Each module can operate in either AC/DC or DC/AC mode, depending on whether it functions on the generator or the grid side. Moreover, each module can be reconfigured from one side to the other, depending on the system’s operational requirements. This is a shining example of full-modular design. This paper aims to model and analyze the reliability of such a modular converter. A Markov modeling approach is applied to the system reliability analysis. In particular, six feasible converter system models based on Hjort’s architecture are investigated. Through numerical analyses and comparison, we provide insights and guidance for converter designers in their decision-making.

Grid-interfacing converter systems with enhanced voltage quality for microgrid application : concept and implementation

NARCIS (Netherlands)

Wang, F.; Duarte, J.L.; Hendrix, M.A.M.

2011-01-01

Grid-interfacing converter systems with enhanced voltage quality are proposed for microgrid application in this paper. By adapting the conventional series-parallel structure, a group of grid-interfacing system topologies are proposed for the purpose of interfacing local generation/microgrid to the

Harmonic models of a back-to-back converter in large offshore wind farms compared with measurement data

DEFF Research Database (Denmark)

Kocewiak, Lukasz Hubert; Hjerrild, Jesper; Bak, Claus Leth

2009-01-01

The offshore wind farm with installed back-to-back power converter in wind turbines is studied. As an example the Burbo Bank offshore wind farm with Siemens Wind Power wind turbines is taken into consideration. The wind farm is simulated in DIgSILENT Power Factory software in order to determine...

Design of DC-DC Converter and its Control for a Wind Generation System Connected to an Isolated Load

Directory of Open Access Journals (Sweden)

Carlos A. Ramírez Gómez

2013-11-01

Full Text Available A method to design a Buck converter and its control, which are associated to a wind generation system that is feeding an isolated load, is presented in this paper. To design the converter a Thevenin equivalent is deduced, which represents the behavior of the wind turbine, the permanent magnet synchronous generator, and the rectifier. The design of the converter elements guarantees input/output voltages and inductor current ripples of 5 % or less. The output voltage control is developed with a proportional-integral-derivative controller and as design criteria a damping of 0,707 and cutoff frequency of 1/5 converter commutation frequency are selected. The designed controller regulates the output voltage faced load perturbations and wind speed variations. 

Hexuple-Inverter Configuration for Multilevel Nine-Phase Symmetrical Open-Winding Converter

DEFF Research Database (Denmark)

Padmanaban, Sanjeevi Kumar; Bhaskar, Mahajan Sagar; Maroti, Pandav Kiran

2016-01-01

Hexuple-inverter configuration for multilevel nine-phase symmetrical open-winding ac converter is articulated in this work. Power modular unit consists of six classical three-phase voltage source inverters (VSI). Each VSI includes one bi-directional device (MOSFET/IGBT) per each phase and link...... software’s (Matlab/PLECS). Results always showed good conformity with the developed theoretical background under working conditions. The proposed converter found suit for (low-voltage/high current) electric vehicles, ac tractions and ‘More-Electric Aircraft’ applications....

Enhancement of galloping-based wind energy harvesting by synchronized switching interface circuits

Science.gov (United States)

Zhao, Liya; Liang, Junrui; Tang, Lihua; Yang, Yaowen; Liu, Haili

2015-04-01

Galloping phenomenon has attracted extensive research attention for small-scale wind energy harvesting. In the reported literature, the dynamics and harvested power of a galloping-based energy harvesting system are usually evaluated with a resistive AC load; these characteristics might shift when a practical harvesting interface circuit is connected for extracting useful DC power. In the family of piezoelectric energy harvesting interface circuits, synchronized switching harvesting on inductor (SSHI) has demonstrated its advantage for enhancing the harvested power from existing base vibrations. This paper investigates the harvesting capability of a galloping-based wind energy harvester using SSHI interfaces, with a focus on comparing the performances of Series SSHI (S-SSHI) and Parallel SSHI (P-SSHI) with that of a standard DC interface, in terms of power at various wind speeds. The prototyped galloping-based piezoelectric energy harvester (GPEH) comprises a piezoelectric cantilever attached with a square-sectioned bluff body made of foam. Equivalent circuit model (ECM) of the GPEH is established and system-level circuit simulations with SSHI and standard interfaces are performed and validated with wind tunnel tests. The benefits of SSHI compared to standard circuit become more significant when the wind speed gets higher; while SSHI circuits lose the benefits at small wind speeds. In both experiment and simulation, the superiority of P-SSHI is confirmed while S-SSHI demands further investigation. The power output is increased by 43.75% with P-SSHI compared to the standard circuit at a wind speed of 6m/s.

Topology and Technology Survey on Medium Voltage Power Converters for Large Wind Turbines

DEFF Research Database (Denmark)

Sztykiel, Michal; Teodorescu, Remus; Munk-Nielsen, Stig

2011-01-01

Based on state-of-the-art within generator and power converter designs, this paper presents and justifies the most promising converter circuitries and concepts for future 10 MW wind turbines. In order to reduce losses and increase efficiency of the turbine, it is assumed that the bulky step...... by various circuit configurations of previously defined power modules....

A novel design of DC-AC electrical machine rotary converter for hybrid solar and wind energy applications

International Nuclear Information System (INIS)

Mohammed, K G; Ramli, A Q; Amirulddin, U A U

2013-01-01

This paper proposes the design of a new bi-directional DC-AC rotary converter machine to convert a d.c. voltage to three-phase voltage and vice-versa using a two-stage energy conversion machine. The rotary converter consists of two main stages which are combined into single frame. These two stages are constructed from three main electromagnetic components. The first inner electromagnetic component represents the input stage that enables the DC power generated by solar energy from photo-voltaic cells to be transformed by the second and third components electro-magnetically to produce multi-phase voltages at the output stage. At the same time, extra kinetic energy from wind, which is sufficiently available, can be added to existing torque on the second electromagnetic component. Both of these input energies will add up to the final energy generated at the output terminals. Therefore, the machine will be able to convert solar and wind energies to the output terminals simultaneously. If the solar energy is low, the available wind energy will be able to provide energy to the output terminals and at the same time charges the batteries which are connected as backup system. At this moment, the machine behaves as wind turbine. The energy output from the machine benefits from two energy sources which are solar and wind. At night when the solar energy is not available and also the load is low, the wind energy is able to charge the batteries and at the same time provides output electrical power to the remaining the load. Therefore, the proposed system will have high usage of available renewable energy as compared to separated wind or solar systems. MATLAB codes are used to calculate the required dimensions, the magnetic and electrical circuits parameters to design of the new bi-directional rotary converter machine.

Open-switch fault detection method of an NPC converter for wind turbine systems

DEFF Research Database (Denmark)

Lee, June-Seok; Lee, Kyo-Beum; Blaabjerg, Frede

2013-01-01

In wind turbine generation (WTG) systems, the neutral-point-clamped (NPC) topology is widely used as the part of a back-to-back converter since the three-level NPC topology has more advantages than the conventional two-level inverter especially for high power. There are twelve switches in the NPC......-switch detection method of the NPC converter is different from that of the NPC inverter due to the different current paths of the NPC converter. This paper proposes the open-switch fault detection method of the NPC converter connected the permanent-magnet synchronous generator (PMSG). Moreover, the open...

Winding design of series AC inductor for dual active bridge converters

DEFF Research Database (Denmark)

Shen, Zhan; Wang, Huai; Shen, Yanfeng

2018-01-01

The ac resistance and parasitic capacitance of the inductor are the primary considerations in the winding design for the dual-active bridge converter (DAB). They are dependent of up to four independent structure variables. The interactive restrictions between those variables makes the design diff...

The Feasibility Study on Thermal Loading Control of Wind Power Converters with a Flexible Switching Frequency

DEFF Research Database (Denmark)

Qin, Zian; Wang, Huai; Blaabjerg, Frede

2015-01-01

Thermal loading of wind power converters is critical to their reliability performance. Especially for IGBT modules applied in a converter, both of the mean value and variation of the junction temperature have significant impact on the lifetime. Besides other strategies to reduce the thermal loadi...... the temperature fluctuations due to wind speed variations. The trade-off between the reduced amplitude of temperature fluctuations and the additional power losses that may be introduced is quantitatively studied....

Impact of Wind Power Plants with Full Converter Wind Turbines on Power System Small-Signal Stability

DEFF Research Database (Denmark)

Knüppel, Thyge; Nygaard Nielsen, Jørgen; Dixon, Andrew

Wind power is being developed in power systems all around the world, and already today wind power covers more than 20 % of the electricity consumption in some countries. As the size of each wind power plant (WPP) increases and as the levels of penetration reaches certain magnitudes, the inclusion...... of the dynamic properties of the WPPs in the power system stability studies become important. The work presented in this report deal with the impact of WPPs based on full converter wind turbines (WTs) on the power system small-signal rotor angle stability. During small disturbances in the power system, the rotor...... speed of the synchronous machines will eventually return to its steady state if the power system is small-signal stable. The dynamic properties of a WPP are fundamentally dierent from those of a synchronous machine, and the interaction of WPPs with the synchronous machines in power system oscillations...

The thermal structure of an air–water interface at low wind speeds

OpenAIRE

Handler, R. A.; Smith, G. B.; Leighton, R. I.

2011-01-01

High-resolution infrared imagery of an air–water interface at wind speeds of 1 to 4 ms⁻¹ wasobtained. Spectral analysis of the data reveals several important features of the thermal structureof the so-called cool skin. At wind speeds for which wind waves are not generated, the interfacialboundary layer appears to be composed of buoyant plumes that are stretched by the surfaceshear as they reach the interface. The plumes appear to form overlapping laminae with ahead–tail...

Control Strategies for Trap Filter Interfaced Three-Phase Grid Connected Converters

DEFF Research Database (Denmark)

Min, Huang

In order to utilize renewable energy systems power electronics are needed to convert the energy to grid. The AC-DC and DC-AC power conversion are dominant in wind power system and photovoltaic system. However, the use of PWM scheme introduces undesirable harmonics. In order to enhance the grid...... damping in order to stabilize the whole system with resonance issue. LC trap filter application for current source converters to reduce the size of the filter and get a higher power factor....... integration of the renewable energy systems, the filter plays an important role. Even though this topic has already been widely studied, there are many optimizations and problems should be solved. How to design a filter for grid-connected converters in distributed generation system to get a lower loss...

Effects of Armature Winding Segmentation with Multiple Converters on the Short Circuit Torque of 10-MW Superconducting Wind Turbine Generators

DEFF Research Database (Denmark)

Liu, Dong; Polinder, Henk; Abrahamsen, Asger Bech

2017-01-01

Superconducting synchronous generators (SCSGs) are drawing more attention in large direct-drive wind turbine applications. Despite low weight and compactness, the short circuit torque of an SCSG may be too high for wind turbine constructions due to a large magnetic air gap of an SCSG. This paper...... aims at assessing the effects of armature winding segmentation on reducing the short circuit torque of 10-MW SCSGs. A concept of armature winding segmentation with multiple power electronic converters is presented. Four SCSG designs using different topologies are examined. Results show that armature...... winding segmentation effectively reduce the short circuit torque in all the four SCSG designs when one segment is shorted at the terminal....

Neural Network Based Maximum Power Point Tracking Control with Quadratic Boost Converter for PMSG—Wind Energy Conversion System

Directory of Open Access Journals (Sweden)

Ramji Tiwari

2018-02-01

Full Text Available This paper proposes an artificial neural network (ANN based maximum power point tracking (MPPT control strategy for wind energy conversion system (WECS implemented with a DC/DC converter. The proposed topology utilizes a radial basis function network (RBFN based neural network control strategy to extract the maximum available power from the wind velocity. The results are compared with a classical Perturb and Observe (P&O method and Back propagation network (BPN method. In order to achieve a high voltage rating, the system is implemented with a quadratic boost converter and the performance of the converter is validated with a boost and single ended primary inductance converter (SEPIC. The performance of the MPPT technique along with a DC/DC converter is demonstrated using MATLAB/Simulink.

Development of a wind energy converter and investigation of its operational function. Part 4: Test setup and results of measurement

Science.gov (United States)

Armbrust, S.; Molly, J. P.

1982-12-01

Measurements made during test operations at the MODA.10 plant as well as at a 25 years old 6 kW wind energy converter are presented. The test arrangements, measurement results of both wind energy converters, and the experience gained are described.

PEMODELAN DAN SIMULASI TOPOLOGI SINGLE ENDED PRIMARY INDUCTOR CONVERTER (SEPIC) UNTUK MINI 3 PLUS WIND TURBINE

OpenAIRE

Prasetiyo, Ryan; Maulana, Dwindra Wilham; Panatarani, Camellia; Joni, I Made

2016-01-01

In order to have a DC-DC buck boost converter with performances as desired specifications, the design process was performed by developing a model and simulation. The purpose of this research was to design a converter applied for a MINI 3 plus Wind Turbine. The converter topology was designed with Single Ended Primary Inductor Converter (SEPIC) using  a Continuous Conduction Mode (CCM). The output specifications of converter are input voltage 60 V, input current 7,5 A, output voltage 25 V...

A SVPWM based on fluctuate capacitor voltage in 3L-NPC back-to-back converter applied to wind energy

DEFF Research Database (Denmark)

Chen, Quan; Wang, Qunjing; Chen, Zhe

2014-01-01

Three-level Neutral-point-clamped (3L-NPC) converters are becoming a realistic alternative to the conventional converters in high-power wind-energy applications. But the unbalance in the supported capacitors' voltage of back-to-back 3L-NPC converters, including the dynamics of the capacitors...... between the fluctuate voltage of upper and lower capacitors is extracted. Based on this error factor the duty-time of every active voltage vector is calculated. In order to validate the model and the control strategy proposed in this paper, a 2MW 3L-NPC converter used in wind energy has been simulated....

Nyquist AD Converters, Sensor Interfaces, and Robustness Advances in Analog Circuit Design, 2012

CERN Document Server

Baschirotto, Andrea; Steyaert, Michiel

2013-01-01

This book is based on the presentations during the 21st workshop on Advances in Analog Circuit Design.  Expert designers provide readers with information about a variety of topics at the frontier of analog circuit design, including Nyquist analog-to-digital converters, capacitive sensor interfaces, reliability, variability, and connectivity.  This book serves as a valuable reference to the state-of-the-art, for anyone involved in analog circuit research and development.  Provides a state-of-the-art reference in analog circuit design, written by experts from industry and academia; Presents material in a tutorial-based format; Includes coverage of Nyquist A/D converters, capacitive sensor interfaces, reliability, variability, and connectivity.

Modeling and Simulation of PMSG Wind Turbine with Boost Converter Working under Discontinuous Conduction Mode

DEFF Research Database (Denmark)

Qin, Nan; Xu, Zhao

2008-01-01

in the discontinuous conducting mode (DCM). The new wind turbine model with the variable speed control of the PMSG based on duty cycle control of the boost converter has been developed in Matlab Simulink. Simulation studies show that DCM working mode of the boost converter provides more flexibility in controlling...

Three port converters used as interface in photovoltaic energy systems

Directory of Open Access Journals (Sweden)

Sarab Al-Chlaihawi

2018-04-01

Full Text Available The aim of this paper is to derive and study a full-bridge three-port converter. Based on the standard design of full-bridge converter, we have modeled and derived a three port converter. The three port converter can be used in renewable energy scenarios, such as solar cells or wind turbines connected to the input port. The input can be taken from two-ports simultaneously or from one port at a time. In order to balance the power mismatch between the input port and load port, the batteries are attached to the third port, to ensure there are no discrepancies in the power generated at the input and power demand at the load. In order to ensure isolation and reduced voltage stress on the switches, a high frequency transformer is also used in the design. The overall design contains four switches, and four diodes. MOSFETs are the strongest candidate for the switches owing to their high switching speed, lower losses and high resistance to higher voltage. Moreover, a buck-boost structure is modeled in order to ensure that it can work for a wide variety of different applications by adjusting the duty cycle of the switches properly. To minimize the switching losses in the converter, Zero-Voltage Switching (ZVS is also achievable in the modeled system.

A Voltage and Frequency Control Strategy for Stand-Alone Full Converter Wind Energy Conversion Systems

Directory of Open Access Journals (Sweden)

Andrés Peña Asensio

2018-02-01

Full Text Available This paper addresses the design and analysis of a voltage and frequency control (VFC strategy for full converter (FC-based wind energy conversion systems (WECSs and its applicability for the supply of an isolated load. When supplying an isolated load, the role of the back-to-back converters in the FC must change with respect to a grid-connected application. Voltage and frequency are established by the FC line side converter (LSC, while the generator side converter (GSC is responsible for maintaining constant voltage in the DC link. Thus, the roles of the converters in the WECS are inverted. Under such control strategies, the LSC will automatically supply the load power and hence, in order to maintain a stable operation of the WECS, the wind turbine (WT power must also be controlled in a load-following strategy. The proposed VFC is fully modelled and a stability analysis is performed. Then, the operation of the WECS under the proposed VFC is simulated and tested on a real-time test bench, demonstrating the performance of the VFC for the isolated operation of the WECS.

A Communication-Supported Comprehensive Protection Strategy for Converter-Interfaced Islanded Microgrids

Directory of Open Access Journals (Sweden)

Dehua Zheng

2018-04-01

Full Text Available The deployment of distributed generators (DGs gives rise to several challenges for a microgrid or conventional distribution feeder, regarding control and protection issues. The major ones are: bi-directional flow of power, changes in fault current magnitude, and continuous changes in operational configuration due to both the plug-and-play of DGs and loads, and the intermittency of the renewable DGs. This issue is exacerbated when the microgrid contains several converter-interfaced DGs and operates in the islanded mode of operation. Hence, conventional protection strategies and relaying techniques will no longer be sufficient to protect islanded microgrids against network faults and disturbance conditions. This paper proposes a fast and reliable communication-supported protection strategy for ensuring the safe operation of converter-interfaced islanded microgrids. The strategy is implementable using commercially accessible microprocessor based digital relays, and is applicable for the protection of low voltage islanded microgrids. It provides backup protection to handle communication failures and malfunctions of protective devices. The paper also presents the detailed structural layout of the digital relay, which executes the proposed protection strategy. A number of improvements are proposed to find an alternative method for conventional overcurrent relays to reliably detect small-magnitude fault currents and high impedance faults, commonly encountered in converter-interfaced islanded microgrids. A simple and economical bus protection method is also proposed. Several simulations are conducted on a comprehensive model of a realistic operational industrial microgrid (Goldwind Smart Microgrid System using PSCAD/EMTDC software environment—for different case studies and fault scenarios—to verify the effectiveness of the present strategy and its digital relay.

Wind farm node connected DFIG/back-to-back converter coupling transient model for grid integration studies

International Nuclear Information System (INIS)

Ostolaza, J.X.; Etxeberria, A.; Zubia, I.

2015-01-01

Highlights: • Full-order DFIG/B2B coupling transient model to the connection of wind farm node. • Algebraic loop between stator and filter currents due to transformer is overcome. • A novel decoupling based control design of grid-side converter is presented. • 24 state-variables describe the DFIG: 15 electro-mechanical, plus 9 for control. • State machine implements the sequential control among its operational modes. - Abstract: This paper presents the explicit electromagnetic transient model of a Doubly Fed Induction Generator (DFIG), that includes its coupling with the back-to-back converter, when the generator/converter set is connected to the wind farm’s Thevenin equivalent, as seen from DFIG’s terminals. Besides that, DFIG’s grid side converter control system is defined in detail, so that expressions for the direct tuning of all compensators are provided. The overall electromechanical wind generator model includes 24 state variables: four mechanical, eleven electrical, and nine more – one for each controller – associated to the control system. The developed model is complemented with a state machine that implements the sequential control among the different stages that define its operational modes. Simulation and experimental results show that the developed model is able to predict the behaviour of the generator in short and long term scenarios.

Power Devices Loading in Multilevel Converters for 10 MW Wind Turbines

DEFF Research Database (Denmark)

Ma, Ke; Blaabjerg, Frede; Xu, Dehong

2011-01-01

Several promising multilevel converter solutions for 10 MW wind turbines using permanent magnet synchronous generators are proposed, designed and compared both with one-stage gear-box drive and direct drive systems. The current and loss distributions, as well as the utilization of power devices......-level NeutralPoint-Clamped topology with both the direct-drive and one-stage gear box drive systems....

Passive Resonant Bidirectional Converter with Galvanic Barrier

Science.gov (United States)

Rosenblad, Nathan S. (Inventor)

2014-01-01

A passive resonant bidirectional converter system that transports energy across a galvanic barrier includes a converter using at least first and second converter sections, each section including a pair of transfer terminals, a center tapped winding; a chopper circuit interconnected between the center tapped winding and one of the transfer terminals; an inductance feed winding interconnected between the other of the transfer terminals and the center tap and a resonant tank circuit including at least the inductance of the center tap winding and the parasitic capacitance of the chopper circuit for operating the converter section at resonance; the center tapped windings of the first and second converter sections being disposed on a first common winding core and the inductance feed windings of the first and second converter sections being disposed on a second common winding core for automatically synchronizing the resonant oscillation of the first and second converter sections and transferring energy between the converter sections until the voltage across the pairs of transfer terminals achieves the turns ratio of the center tapped windings.

A novel double quad-inverter configuration for multilevel twelve-phase open-winding converter

DEFF Research Database (Denmark)

Padmanaban, Sanjeevi Kumar; Blaabjerg, Frede; Wheeler, Patrick William

2016-01-01

This paper describes a novel proposal of double quad-inverter configuration for multilevel twelve-phase open-winding ac converter. Modular power units are developed from reconfigured eight classical three-phase voltage source inverters (VSIs). Each VSI has one additional bi-directional switching...... numerical simulation software's (Matlab/PLECS) developments. Further, the results confirm the good agreement to the developed theoretical background. Proposed converter suits the need of low-voltage/high-current applications such as ac tractions and `More-Electric Aircraft' propulsion systems....

The Impact of Power Switching Devices on the Thermal Performance of a 10 MW Wind Power NPC Converter

Directory of Open Access Journals (Sweden)

Ke Ma

2012-07-01

Full Text Available Power semiconductor switching devices play an important role in the performance of high power wind energy generation systems. The state-of-the-art device choices in the wind power application as reported in the industry include IGBT modules, IGBT press-pack and IGCT press-pack. Because of significant deviation in the packaging structure, electrical characteristics, as well as thermal impedance, these available power switching devices may have various thermal cycling behaviors, which will lead to converter solutions with very different cost, size and reliability performance. As a result, this paper aimed to investigate the thermal related characteristics of some important power switching devices. Their impact on the thermal cycling of a 10 MW three-level Neutral-Point-Clamped wind power converter is then evaluated under various operating conditions; the main focus will be on the grid connected inverter. It is concluded that the thermal performances of the 3L-NPC wind power converter can be significantly changed by the power device technology as well as their parallel configurations.

Modular Multi-level converter based HVDC System for Grid Connection of Offshore Wind Power Plant

DEFF Research Database (Denmark)

Gnanarathna, U.N.; Chaudhary, Sanjay Kumar; Gole, A.M.

2010-01-01

This paper explores the application of modular multi-level converters (MMC) as a means for harnessing the power from off-shore wind power plants. The MMC consists of a large number of simple voltage sourced converter (VSC) submodules that can be easily assembled into a converter for high......-voltage and high power. The paper shows that the MMC converter has a fast response and low harmonic content in comparison with a two-level VSC option. The paper discusses the modeling approach used, including a solution to the modeling challenge imposed by the very large number of switching devices in the MMC....

A Wind Farm Electrical Systems Evaluation with EeFarm-II

Directory of Open Access Journals (Sweden)

Jan Pierik

2010-03-01

Full Text Available EeFarm-II is used to evaluate 13 different electrical systems for a 200 MW wind farm with a 100 km connection to shore. The evaluation is based on component manufacturer data of 2009. AC systems are compared to systems with DC connections inside the wind farm and DC connection to shore. Two options have the best performance for this wind farm size and distance: the AC system and the system with a DC connection to shore. EeFarm-II is a user friendly computer program for wind farm electrical and economic evaluation. It has been built as a Simulink Library in the graphical interface of Matlab-Simulink. EeFarm-II contains models of wind turbines, generators, transformers, AC cables, inductors, nodes, splitters, PWM converters, thyristor converters, DC cables, choppers and statcoms.

Control and modulation for loss minimization for dc/dc converters in wind farm

DEFF Research Database (Denmark)

Dincan, Catalin Gabriel; Kjær, Philip Carne

2016-01-01

For a DC wind turbine, a single phase series-resonant converter for unidirectional power is studied. This paper aims to identify and compare impact on electrical losses and component ratings from the choice of three candidate control strategies. The evaluation is purely based on circuit simulatio...

Power converter with maximum power point tracking MPPT for small wind-electric pumping systems

International Nuclear Information System (INIS)

Lara, David; Merino, Gabriel; Salazar, Lautaro

2015-01-01

Highlights: • We implement a wind electric pumping system of small power. • The power converter allowed to change the operating point of the electro pump. • Two control techniques were implemented in the power converter. • The control V/f variable allowed to increase the power generated by the permanent magnet generator. - Abstract: In this work, an AC–DC–AC direct-drive power converter was implemented for a wind electric pumping system consisting of a permanent magnet generator (PMG) of 1.3 kW and a peripheral single phase pump of 0.74 kW. In addition, the inverter linear V/f control scheme and the maximum power point tracking (MPPT) algorithm with variable V/f were developed. MPPT algorithm seeks to extract water in a wide range of power input using the maximum amount of wind power available. Experimental trials at different pump pressures were conducted. With a MPPT tracking system with variable V/f, a power value of 1.3 kW was obtained at a speed of 350 rpm and a maximum operating hydraulic head of 50 m. At lower operating heads pressures (between 10 and 40 m), variable V/f control increases the power generated by the PMG compared to the linear V/f control. This increase ranged between 4% and 23% depending on the operating pressure, with an average of 13%, getting close to the maximum electrical power curve of the PMG. The pump was driven at variable frequency reaching a minimum speed of 0.5 times the rated speed. Efficiency of the power converter ranges between 70% and 95% with a power factor between 0.4 and 0.85, depending on the operating pressure

The application of standardized control and interface circuits to three dc to dc power converters.

Science.gov (United States)

Yu, Y.; Biess, J. J.; Schoenfeld, A. D.; Lalli, V. R.

1973-01-01

Standardized control and interface circuits were applied to the three most commonly used dc to dc converters: the buck-boost converter, the series-switching buck regulator, and the pulse-modulated parallel inverter. The two-loop ASDTIC regulation control concept was implemented by using a common analog control signal processor and a novel digital control signal processor. This resulted in control circuit standardization and superior static and dynamic performance of the three dc-to-dc converters. Power components stress control, through active peak current limiting and recovery of switching losses, was applied to enhance reliability and converter efficiency.

Modeling and Comparison of Power Converters for Doubly Fed Induction Generators in Wind Turbines

DEFF Research Database (Denmark)

Helle, Lars

on the generated power quality and controllability. A consequence of this increased focus has been an ever increased set of requirements formulated in national grid requirement. These requirements has forced wind turbines to evolve from a simple generator on a stick into complicated miniature power plants......During the last decades, renewable energy resources have become an ever increasing part of the world wide power generation and especially energy produced by wind turbines has captured a significant part of this power production. This large penetration of wind power has caused increased focus...... on the design engineers employed in the wind industry. Such a progress may force design engineers to adopt common practice from more or less related technologies rather than finding the optimum solution for the specific application. For instance when applying power electronic converters to wind turbines...

Induced Torques on Synchronous Generators from Operation of Wind Power Plant based on Full-Load Converter Interfaced Wind Turbines

DEFF Research Database (Denmark)

Knüppel, Thyge; Nielsen, Jørgen N.; Jensen, Kim H.

2011-01-01

It is expected that large wind power plants (WPP) contribute to stable and reliable operation of the electric power system. This includes participation with delivery of system services such as voltage and frequency support. With variable-speed WPPs this can be achieved by adding auxiliary...... be predicted with the presented method. The work is based on a nonlinear, dynamic model of the 3.6 MW Siemens Wind Power wind turbine....... controllers that control the active and reactive power output accordingly. While being designed for a given system service, any feedback control affects the closed-loop behavior of the overall system and thereby its small-signal stability properties. Eigenvalue analysis conveniently determines the stability...

Considerations and Optimization of Time-Resolved PIV Measurements near Complex Wind-Generated Air-Water Wave Interface

Science.gov (United States)

Stegmeir, Matthew; Markfort, Corey

2017-11-01

Time Resolved PIV measurements are applied on both sides of air-water interface in order to study the coupling between air and fluid motion. The multi-scale and 3-dimensional nature of the wave structure poses several unique considerations to generate optimal-quality data very near the fluid interface. High resolution and dynamic range in space and time are required to resolve relevant flow scales along a complex and ever-changing interface. Characterizing the two-way coupling across the air-water interface provide unique challenges for optical measurement techniques. Approaches to obtain near-boundary measurement on both sides of interface are discussed, including optimal flow seeding procedures, illumination, data analysis, and interface tracking. Techniques are applied to the IIHR Boundary-Layer Wind-Wave Tunnel and example results presented for both sides of the interface. The facility combines a 30m long recirculating water channel with an open-return boundary layer wind tunnel, allowing for the study of boundary layer turbulence interacting with a wind-driven wave field.

Instability of Wind Turbine Converters during Current Injection to Low Voltage Grid Faults and PLL Frequency Based Stability Solution

DEFF Research Database (Denmark)

Göksu, Ömer; Teodorescu, Remus; Bak, Claus Leth

2014-01-01

In recent grid codes for wind power integration, wind turbines are required to stay connected during grid faults even when the grid voltage drops down to zero; and also to inject reactive current in proportion to the voltage drop. However, a physical fact, instability of grid-connected converters...... during current injection to very low (close to zero) voltage faults, has been omitted, i.e., failed to be noticed in the previous wind power studies and grid code revisions. In this paper, the instability of grid side converters of wind turbines defined as loss of synchronism (LOS), where the wind...... turbines lose synchronism with the grid fundamental frequency (e.g., 50 Hz) during very deep voltage sags, is explored with its theory, analyzed and a novel stability solution based on PLL frequency is proposed; and both are verified with power system simulations and by experiments on a grid...

Sliding Mode Control of PMSG Wind Turbine Based on Enhanced Exponential Reaching Law

DEFF Research Database (Denmark)

Mozayan, Seyed Mehdi; Saad, Maarouf; Vahedi, Hani

2016-01-01

This paper proposes a Sliding Mode Control (SMC) based scheme for a variable speed, direct-driven Wind Energy Conversion Systems (WECS) equipped with Permanent Magnet Synchronous Generator (PMSG) connected to the grid. In this work, diode rectifier, boost converter, Neutral Point Clamped (NPC......) inverter and L filter are used as the interface between the wind turbine and grid. This topology has abundant features such as simplicity for low and medium power wind turbine applications. It is also less costly than back-to-back two-level converters in medium power applications. SMC approach demonstrates...... is explored by simulation study on a 4 kW wind turbine, and then verified by experimental tests for a 2 kW set-up....

Flicker Mitigation by Active Power Control of Variable-Speed Wind Turbines With Full-Scale Back-to-Back Power Converters

DEFF Research Database (Denmark)

Hu, Weihao; Chen, Zhe; Wang, Zhaoan

2009-01-01

/EMTDC. Flicker emission of this system is investigated. Reactive power compensation is mostly adopted for flicker mitigation. However, the flicker mitigation technique shows its limits, when the grid impedance angle is low in some distribution networks. A new method of flicker mitigation by controlling active...... power is proposed. It smoothes the 3p active power oscillations from wind shear and tower shadow effects of the wind turbine by varying the dc-link voltage of the full-scale converter. Simulation results show that damping the 3p active power oscillation by using the flicker mitigation controller...... is an effective means for flicker mitigation of variable-speed wind turbines with full-scale back-to-back power converters during continuous operation....

A Predictive Power Control Strategy for DFIGs Based on a Wind Energy Converter System

Directory of Open Access Journals (Sweden)

Xiaoliang Yang

2017-07-01

Full Text Available A feasible control strategy is proposed to control a doubly fed induction generator based on the wind energy converter system (DFIG-WECS. The main aim is to enhance the steady state and dynamic performance under the condition of the parameter perturbations and external disturbances and to satisfy the stator power response of the system. Within the proposed control method, the control scheme for the rotor side converter (RSC is developed on the model predictive control. Firstly, the self-adaptive reference trajectory is established from the deduced discrete state-space equation of the generator. Then, the rotor voltage is calculated by minimizing the global performance index under the current prediction steps at the sampling instant. Through the control scheme for the grid side converter (GSC and wind turbine, we have re-applied the conventional control. The effectiveness of the proposed control strategy is verified via time domain simulation of a 150 kW-575 V DFIG-WECS using Matlab/Simulink. The simulation result shows that the control of the DFIG with the proposed control method can enhance the steady and dynamic response capability better than the conventional ones when the system faces errors due to the parameter perturbations, external disturbances and the rotor speed.

A real time measurement of junction temperature variation in high power IGBT modules for wind power converter application

DEFF Research Database (Denmark)

Ghimire, Pramod; Pedersen, Kristian Bonderup; de Vega, Angel Ruiz

2014-01-01

This paper presents a real time measurement of on-state forward voltage and estimating the junction temperature for a high power IGBT module during a power converter operation. The power converter is realized as it can be used for a wind turbine system. The peak of the junction temperature is dec...

Power density investigation on the press-pack IGBT 3L-HB-VSCs applied to large wind turbine

DEFF Research Database (Denmark)

Senturk, Osman Selcuk; Munk-Nielsen, Stig; Teodorescu, Remus

2011-01-01

capabilities, DC capacitor sizes, converter cabinet volumes of the three 3LHB- VSCs utilizing press-pack IGBTs are investigated in order to quantify and compare the power densities of the 3L-HB-VSCs employed as grid-side converters. Also, the suitable transformer types for the 3L-HB-VSCs are determined......With three different DC-side and AC-side connections, the three-level H-bridge voltage source converters (3L-HB-VSCs) are alternatives to 3L neutral-point-clamped VSCs (3L-NPC-VSCs) for interfacing large wind turbines with electricity grids. In order to assess their feasibility for large wind...... turbines, they should be investigated in terms of power density, which is one of the most important design criteria for wind turbine converters due to turbine nacelle space limitation. In this study, by means of the converter electro-thermal models based on the converter characteristics, the power...

Control of frequency converters for wind power systems with doubly fed asynchronous generators; Regelung von Frequenzumrichtern fuer Windenergieanlagen mit doppelt gespeistem Asynchrongenerator

Energy Technology Data Exchange (ETDEWEB)

Engelhardt, Stephan [Woodward SEG GmbH und Co. KG, Kempen (Germany)

2007-07-01

Modern wind energy systems are characterized by an extensive use of power electronics. Using complex converter systems is technically and commercially very attractive as it allows an optimized operation of the wind turbine in regard to efficiency, reduced stress to the drive train due to variable speed and feeding wind power with high quality into the grid. For some years wind energy systems with frequency converter and doubly fed asynchronous generator have the biggest market share. The main requirements from grid codes regarding fault ride through operation will be summarized and enhanced control algorithms for this special type of system will be presented. (orig.)

Isolated/Non-Isolated Quad-Inverter Configuration for Multilevel Symmetrical/Asymmetrical Dual Six-Phase Star-Winding Converter

DEFF Research Database (Denmark)

Padmanaban, Sanjeevi Kumar; Hontz, Michael R.; Khanna, Raghav

2016-01-01

This article presents the developments of a novel isolated/non-isolated quad inverter configuration for multilevel dual six-phase (twelve-phase) star-winding converter. The modular circuit consists of four standard voltage source inverters (VSIs). Each VSI is incorporated with one bi-directional ...... systems, electrical vehicles, AC tractions, and `More-Electric Aircraft' propulsion systems....... converter is numerically modeled using Matlab/PLECS simulation software and the predicted behavior of the system is analyzed and presented. Good agreement is obtained between these results and the theoretical analysis. Suitable applications for the converter include (low-voltage/high-current) medium power...

A New Method for Start-up of Isolated Boost Converters Using Magnetic- and Winding-Integration

DEFF Research Database (Denmark)

Lindberg-Poulsen, Kristian; Ouyang, Ziwei; Sen, Gökhan

2012-01-01

. The traditional added flyback winding coupled to the boost inductor is thus eliminated from the circuit, bringing substantial cost savings, increased efficiency and simplified design. Each subinterval of the converter operation is described through electrical and magnetic circuit diagrams, and the concept...

Modeling, Simulation and Control of Matrix Convert for Variable Speed Wind Turbine System

Directory of Open Access Journals (Sweden)

M. Alizadeh Moghadam

2015-09-01

Full Text Available This paper presents modeling, simulation and control of matrix converter (MC for variable speed wind turbine (VSWT system including permanent magnet synchronous generator (PMSG. At a given wind velocity, the power available from a wind turbine is a function of its shaft speed. In order to track maximum power, the MC adjusts the PMSG shaft speed.The proposed control system allowing independent control maximum power point tracking (MPPT of generator side and regulate reactive power of grid side for the operation of the VSWT system. The MPPT is implemented by a new control system. This control system is based on control of zero d-axis current (ZDC. The ZDC control can be realized by transfer the three-phase stator current in the stationary reference frame into d-and q-axis components in the synchronous reference frame. Also this paper is presented, a novel control strategy to regulate the reactive power supplied by a variable speed wind energy conversion system. This control strategy is based on voltage oriented control (VOC. The simulation results based on Simulink/Matlab software show that the controllers can extract maximum power and regulate reactive power under varying wind velocities.

Operation and thermal loading of three-level Neutral-Point-Clamped wind power converter under various grid faults

DEFF Research Database (Denmark)

Ma, Ke; Blaabjerg, Frede; Liserre, Marco

2012-01-01

In order to fulfill the continuous growing grid-side demands, the full-scale power converters are becoming more and more popular in the wind power application. Nevertheless, the more severe loading of the power semiconductor devices in the full-scale power converters, especially during Low Voltage...... Ride Through (LVRT) operation under grid faults, may compromise the reliability of the system and consequently further increase its cost. In this paper, the impact of various grid faults on a three-level Neutral-Point-Clamped (3L-NPC) grid-converter in terms of thermal loading of power semiconductor...

Modulation Methods for Neutral-Point-Clamped Wind Power Converter Achieving Loss and Thermal Redistribution Under Low-Voltage Ride-Through

DEFF Research Database (Denmark)

Ma, Ke; Blaabjerg, Frede

2014-01-01

The three-level neutral-point (NP)-clamped (3L-NPC) converter is a promising multilevel topology in the application of megawatt wind power generation systems. However, the growing requirements by grid codes may impose high stress and even give reliability problem to this converter topology......, with the proposed modulation methods, the thermal distribution in the 3L-NPC wind power inverter undergoing LVRT becomes more equal, and the junction temperature of the most stressed devices can be also relieved. Also, the control ability of the dc-bus NP potential, which is one of the crucial considerations...

Integration of an open interface PC scene generator using COTS DVI converter hardware

Science.gov (United States)

Nordland, Todd; Lyles, Patrick; Schultz, Bret

2006-05-01

Commercial-Off-The-Shelf (COTS) personal computer (PC) hardware is increasingly capable of computing high dynamic range (HDR) scenes for military sensor testing at high frame rates. New electro-optical and infrared (EO/IR) scene projectors feature electrical interfaces that can accept the DVI output of these PC systems. However, military Hardware-in-the-loop (HWIL) facilities such as those at the US Army Aviation and Missile Research Development and Engineering Center (AMRDEC) utilize a sizeable inventory of existing projection systems that were designed to use the Silicon Graphics Incorporated (SGI) digital video port (DVP, also known as DVP2 or DD02) interface. To mate the new DVI-based scene generation systems to these legacy projection systems, CG2 Inc., a Quantum3D Company (CG2), has developed a DVI-to-DVP converter called Delta DVP. This device takes progressive scan DVI input, converts it to digital parallel data, and combines and routes color components to derive a 16-bit wide luminance channel replicated on a DVP output interface. The HWIL Functional Area of AMRDEC has developed a suite of modular software to perform deterministic real-time, wave band-specific rendering of sensor scenes, leveraging the features of commodity graphics hardware and open source software. Together, these technologies enable sensor simulation and test facilities to integrate scene generation and projection components with diverse pedigrees.

Converter topologies and control

Energy Technology Data Exchange (ETDEWEB)

Rodriguez, Fernando; Qin, Hengsi; Chapman, Patrick

2018-05-01

An inverter includes a transformer that includes a first winding, a second winding, and a third winding, a DC-AC inverter electrically coupled to the first winding of the transformer, a cycloconverter electrically coupled to the second winding of the transformer, an active filter electrically coupled to the third winding of the transformer. The DC-AC inverter is adapted to convert the input DC waveform to an AC waveform delivered to the transformer at the first winding. The cycloconverter is adapted to convert an AC waveform received at the second winding of the transformer to the output AC waveform having a grid frequency of the AC grid. The active filter is adapted to sink and source power with one or more energy storage devices based on a mismatch in power between the DC source and the AC grid.

Application of a synchronous generator with a boost converter in wind turbines: an experimental overview

DEFF Research Database (Denmark)

Sharma, Ranjan; Rasmussen, Tonny Wederberg; Jensen, Bogi Bech

2012-01-01

An electrical structure of a variable-speed wind turbine based on an externally excited synchronous generator; a passive diode rectifier; and a boost converter is discussed in this study. The clear advantage of such a system is its lower-semi-conductor devices count. A brief theoretical explanation...... of such a system is included. A boost converter normally utilies an inductor (energy storage) to boost the voltage level from its input to a higher output value. This study analyses the possibility of using the generator inductance as a boost inductor. It is discussed and verified in the study that for the given...... switching frequency of the boost converter (fs=1= kHz), the generator sub-transient inductance (not the synchronous inductance) appears as an equivalent inductance seen by the boost converter. The parasitic capacitors present in the generator terminals are often neglected from design issues. It is presented...

User Interface Technology Transfer to NASA's Virtual Wind Tunnel System

Science.gov (United States)

vanDam, Andries

1998-01-01

Funded by NASA grants for four years, the Brown Computer Graphics Group has developed novel 3D user interfaces for desktop and immersive scientific visualization applications. This past grant period supported the design and development of a software library, the 3D Widget Library, which supports the construction and run-time management of 3D widgets. The 3D Widget Library is a mechanism for transferring user interface technology from the Brown Graphics Group to the Virtual Wind Tunnel system at NASA Ames as well as the public domain.

Frequency Activated Fast Power Reserve for Wind Power Plant Delivered from Stored Kinetic Energy in the Wind Turbine Inertia

DEFF Research Database (Denmark)

Knüppel, Thyge; Thuring, P.; Kumar, S

2011-01-01

is proposed that delivers a short-term power reserve from the kinetic energy in the wind turbine (WT) inertia, while considering the inherent characteristics of a wind power plant. The aim is to contribute with a fast power reserve to stabilize the frequency drop during large and sudden production deficits......With increased penetration of converter interfaced generation, synchronous generators may start to be displaced to keep the overall power balance. As a consequence the resulting inertia in the system may decrease and make the power system more exposed to frequency excursions. Here, a control...

Impact of modulation strategies on power devices loading for 10 MW multilevel wind power converter

DEFF Research Database (Denmark)

Blaabjerg, Frede; Isidori, Andrea; Rossi, Fabio Mario

2012-01-01

This paper focuses on the control and modulation of a three-level Neutral Point Clamped (3L-NPC) back-to-back full scale converter for a 10 MW direct-drive wind turbine, equipped with a Permanent Magnet Synchronous Generator (PMSG). Emphasis is oriented towards the investigation of the power losses...

Performance tests of a power-electronics converter for multi-megawatt wind turbines using a grid emulator

International Nuclear Information System (INIS)

Averous, Nurhan Rizqy; Berthold, Anica; Monti, Antonello; De Doncker, Rik W.; Schneider, Alexander; Schwimmbeck, Franz

2016-01-01

A vast increase of wind turbines (WT) contribution in the modern electrical grids have led to the development of grid connection requirements. In contrast to the conventional test method, testing power-electronics converters for WT using a grid emulator at Center for Wind Power Drives (CWD) RWTH Aachen University offers more flexibility for conducting test scenarios. Further analysis on the performance of the device under test (DUT) is however required when testing with grid emulator since the characteristic of the grid emulator might influence the performance of the DUT. This paper focuses on the performance analysis of the DUT when tested using grid emulator. Beside the issue regarding the current harmonics, the performance during Fault Ride-Through (FRT) is discussed in detail. A power hardware in the loop setup is an attractive solution to conduct a comprehensive study on the interaction between the power-electronics converters and the electrical grids. (paper)

Performance tests of a power-electronics converter for multi-megawatt wind turbines using a grid emulator

Science.gov (United States)

Rizqy Averous, Nurhan; Berthold, Anica; Schneider, Alexander; Schwimmbeck, Franz; Monti, Antonello; De Doncker, Rik W.

2016-09-01

A vast increase of wind turbines (WT) contribution in the modern electrical grids have led to the development of grid connection requirements. In contrast to the conventional test method, testing power-electronics converters for WT using a grid emulator at Center for Wind Power Drives (CWD) RWTH Aachen University offers more flexibility for conducting test scenarios. Further analysis on the performance of the device under test (DUT) is however required when testing with grid emulator since the characteristic of the grid emulator might influence the performance of the DUT. This paper focuses on the performance analysis of the DUT when tested using grid emulator. Beside the issue regarding the current harmonics, the performance during Fault Ride-Through (FRT) is discussed in detail. A power hardware in the loop setup is an attractive solution to conduct a comprehensive study on the interaction between the power-electronics converters and the electrical grids.

A Novel Multilevel Quad-Inverter Configuration for Quasi Six-Phase Open-Winding Converter

DEFF Research Database (Denmark)

Padmanaban, Sanjeevi Kumar; Blaabjerg, Frede; Wheeler, Patrick

2016-01-01

This paper developed a novel quad-inverter configuration for multilevel six-phase asymmetrical open-winding AC converter. Proposal found to be suited for (low-voltage/high-current) applications such as AC tractions and `More-Electric Aircraft' propulsion systems. Modular power circuit comprises...... of standard four three-phase voltage source inverter (VSI) and each connected to the open-end windings. Each VSIs are incorporated with one bi-directional switching device (MOSFET/IGBT) per phase and two capacitors with neutral point connected. Further, an original modified single carrier five...... and quadruples the capabilities of VSIs. A set of observed results is presented with numerical software analysis (Matlab/PLECS) in balanced working conditions. Always the results shown good agreement in the developed theoretical background....

Characterization of diode valve in medium voltage dc/dc converter for wind turbines

DEFF Research Database (Denmark)

Dincan, Catalin Gabriel; Kjær, Philip Carne

2016-01-01

This paper proposes a methodology for characterization of medium voltage (MV), medium frequency (MF) rectifier diode valve. The intended application is for 10MW dc/dc converters used in DC offshore wind turbines. Sensitivity to semiconductor component parameter variation, snubber component tolera...... tolerance, influence of temperature and stray capacitance are analyzed. It is concluded that the largest impact on sensitivity is given by reverse recovery charge variation and differences of temperature between adjacent devices....

A High Step-Down Interleaved Buck Converter with Active-Clamp Circuits for Wind Turbines

Directory of Open Access Journals (Sweden)

Chih-Lung Shen

2012-12-01

Full Text Available In this paper, a high step-down interleaved buck coupled-inductor converter (IBCC with active-clamp circuits for wind energy conversion has been studied. In high step-down voltage applications, an IBCC can extend duty ratio and reduce voltage stresses on active switches. In order to reduce switching losses of active switches to improve conversion efficiency, a IBCC with soft-switching techniques is usually required. Compared with passive-clamp circuits, the IBCC with active-clamp circuits have lower switching losses and minimum ringing voltage of the active switches. Thus, the proposed IBCC with active-clamp circuits for wind energy conversion can significantly increase conversion efficiency. Finally, a 240 W prototype of the proposed IBCC with active-clamp circuits was built and implemented. Experimental results have shown that efficiency can reach as high as 91%. The proposed IBCC with active-clamp circuits is presented in high step-down voltage applications to verify the performance and the feasibility for energy conversion of wind turbines.

A New Coordinated Voltage Control Scheme for Offshore AC Grid of HVDC Connected Offshore Wind Power Plants

DEFF Research Database (Denmark)

Sakamuri, Jayachandra N.; Cutululis, Nicolaos Antonio; Rather, Zakir Hussain

2015-01-01

This paper proposes a coordinated voltage control scheme (CVCS) which enhances the voltage ride through (VRT) capability of an offshore AC grid comprised of a cluster of offshore wind power plants (WPP) connected through AC cables to the offshore voltage source converter based high voltage DC (VSC......-HVDC) converter station. Due to limited short circuit power contribution from power electronic interfaced variable speed wind generators and with the onshore main grid decoupled by the HVDC link, the offshore AC grid becomes more vulnerable to dynamic voltage events. Therefore, a short circuit fault...... in the offshore AC Grid is likely to have significant implications on the voltage of the offshore AC grid, hence on the power flow to the onshore mainland grid. The proposed CVCS integrates individual local reactive power control of wind turbines and of the HVDC converter with the secondary voltage controller...

Reliability Estimation with Uncertainties Consideration for High Power IGBTs in 2.3 MW Wind Turbine Converter System

DEFF Research Database (Denmark)

Kostandyan, Erik; Ma, Ke

2012-01-01

This paper investigates the lifetime of high power IGBTs (insulated gate bipolar transistors) used in large wind turbine applications. Since the IGBTs are critical components in a wind turbine power converter, it is of great importance to assess their reliability in the design phase of the turbine....... Minimum, maximum and average junction temperatures profiles for the grid side IGBTs are estimated at each wind speed input values. The selected failure mechanism is the crack propagation in solder joint under the silicon die. Based on junction temperature profiles and physics of failure model......, the probabilistic and determinist damage models are presented with estimated fatigue lives. Reliably levels were assessed by means of First Order Reliability Method taking into account uncertainties....

Grid Converters for Stationary Battery Energy Storage Systems

DEFF Research Database (Denmark)

Trintis, Ionut

The integration of renewable energy sources in the power system, with high percentage, is a well known challenge nowadays. Power sources like wind and solar are highly volatile, with uctuations on various time scales. One long term solution is to build a continentwide or worldwide supergrid....... Another solution is to use distributed energy storage units, and create virtual power plants. Stationary energy storage is a complementary solution, which can postpone the network expansion and can be optimized for dierent kind of grid services. As an energy storage solution with timing for few seconds...... multilevel converter structure with integrated energy storage is introduced. This converter structure is suitable to interface low and medium voltage energy storage units to medium and high voltage grids. It can also interconnect a DC and AC grid with bidirectional power ow, were both can be backed...

Thermal analysis of multilevel grid side converters for 10 MW wind turbines under Low Voltage Ride Through

DEFF Research Database (Denmark)

Ma, Ke; Blaabjerg, Frede; Liserre, Marco

2011-01-01

, and able to contribute to the grid recovery by injecting reactive current during grid faults. Consequently, the full-scale power converter solutions are becoming more and more popular to fulfill the growing challenges in the wind power application. Nevertheless, the loading of the power devices in full...

Load Flow Analysis of Hybrid AC-DC Power System with Offshore Wind Power

DEFF Research Database (Denmark)

Dhua, Debasish; Huang, Shaojun; Wu, Qiuwei

2017-01-01

The offshore wind power has received immense attention because of higher wind speed and lower opposition for construction. A wide range of combinations of high-voltage ACDC transmission have been proposed for integrating offshore wind farms and long-distance power transmission. This paper...... is to model such hybrid AC-DC systems including the interfacing converters, which have several control parameters that can change the load flow of the hybrid systems. Then, the paper proposes a Load Flow algorithm based on the Newton-Raphson method, which covers three different section types...

Control strategy of wind turbine based on permanent magnet synchronous generator and energy storage for stand-alone systems

DEFF Research Database (Denmark)

Deng, Fujin; Liu, Dong; Chen, Zhe

2017-01-01

This paper investigates a variable speed wind turbine based on permanent magnet synchronous generator and a full-scale power converter in a stand-alone system. An energy storage system(ESS) including battery and fuel cell-electrolyzer combination is connected to the DC link of the full-scale power...... converter through the power electronics interface. Wind is the primary power source of the system, the battery and FC-electrolyzer combination is used as a backup and a long-term storage system to provide or absorb power in the stand-alone system, respectively. In this paper, a control strategy is proposed...... for the operation of this variable speed wind turbine in a stand-alone system, where the generator-side converter and the ESS operate together to meet the demand of the loads. This control strategy is competent for supporting the variation of the loads or wind speed and limiting the DC-link voltage of the full...

Adaptive Hysteresis Band Current Control (AHB) with PLL of Grid Side Converter-Based Wind Power Generation System

DEFF Research Database (Denmark)

Guo, Yougui; Zeng, Ping; Li, Lijuan

2011-01-01

Adaptive hysteresis band current control(AHB CC) is used to control the three-phase grid currents by means of grid side converter in wind power generation system in this paper. AHB has reached the good purpose with PLL (Lock phase loop). First the mathematical models of each part are given......, transformer and grid, and control parts, etc. The simulation results have verified that the control strategy is feasible to fit for control of gird currents, active power, reactive power and DC-link voltage in wind power generation system....

Performance evaluation of a three-phase dual active bridge DC-DC converter with different transformer winding configurations

NARCIS (Netherlands)

Baars, N.; Everts, J.; Wijnands, K.; Lomonova, E.

2016-01-01

This paper investigates the impact of three transformer winding configurations, i.e. the Y-Y, the Y-Delta, and the Delta-Delta configuration, on the performance of a three-phase dual active bridge (DAB) dc–dc converter. For each configuration, equations for the phase currents, power flow, and zero

Operation and Control of a Direct-Driven PMSG-Based Wind Turbine System with an Auxiliary Parallel Grid-Side Converter

Directory of Open Access Journals (Sweden)

Jiawei Chu

2013-07-01

Full Text Available In this paper, based on the similarity, in structure and principle, between a grid-connected converter for a direct-driven permanent magnet synchronous generator (D-PMSG and an active power filter (APF, a new D-PMSG-based wind turbine (WT system configuration that includes not only an auxiliary converter in parallel with the grid-side converter, but also a coordinated control strategy, is proposed to enhance the low voltage ride through (LVRT capability and improve power quality. During normal operation, the main grid-side converter maintains the DC-link voltage constant, whereas the auxiliary grid-side converter functions as an APF with harmonic suppression and reactive power compensation to improve the power quality. During grid faults, a hierarchical coordinated control scheme for the generator-side converter, main grid-side converter and auxiliary grid-side converter, depending on the grid voltage sags, is presented to enhance the LVRT capability of the direct-driven PMSG WT. The feasibility and the effectiveness of the proposed system’s topology and hierarchical coordinated control strategy were verified using MATLAB/Simulink simulations.

Dual Converter Fed Open-End Transformer Topology with Parallel Converters and Integrated Magnetics

DEFF Research Database (Denmark)

Gohil, Ghanshyamsinh Vijaysinh; Bede, Lorand; Teodorescu, Remus

2016-01-01

that flows between the parallel interleaved VSCs. An integrated inductor is proposed which suppresses the circulating current in both the converter groups. In addition, the functionality of the line filter inductor is also integrated. Flux in various parts of the integrated inductor is analyzed and a design......A converter system for high power applications, connected to a medium-voltage network using a stepup transformer, is presented in this paper. The converterside winding of the transformer is configured as an openend and both the ends of the windings are fed from two different converter groups. Each...... procedure is also described. The volume and the losses of the proposed solution are compared with that of the state-of-art solution. The control of the proposed converter system is also discussed. The analysis has been verified by the simulation and experimental results....

Parallel combination of FC and UC for vehicular power systems using a multi-input converter-based power interface

Energy Technology Data Exchange (ETDEWEB)

Vural, B.; Erdinc, O.; Uzunoglu, M. [Department of Electrical Engineering, Yildiz Technical University, Istanbul 34349 (Turkey)

2010-12-15

Fuel cells (FC) are widely recognized as one of the most promising technologies to meet future power requirements of vehicular applications. However, a FC system combined with an energy storage system (ESS) can perform better for vehicle propulsion as considering several points. As the additional ESS can fulfill the transient power demand fluctuations, the FC system can be downsized to fit the base power demand without facing peak loads. Besides, braking energy can be recovered by the ESS. Interfacing of traction drive requirements with characteristics and modes of operation of on-board generation units and ESSs calls for suitable power electronic converter configuration. In this paper, a FC/UC hybrid vehicular power system using a multi-input converter-based power interface is proposed. The applied power interface topology ensures the active power sharing and DC link voltage stabilization for the hybrid vehicular system. The mathematical and electrical models of the hybrid vehicular system are developed in detail and simulated using MATLAB registered, Simulink registered and SimPowerSystems registered environments. (author)

Parallel combination of FC and UC for vehicular power systems using a multi-input converter-based power interface

International Nuclear Information System (INIS)

Vural, B.; Erdinc, O.; Uzunoglu, M.

2010-01-01

Fuel cells (FC) are widely recognized as one of the most promising technologies to meet future power requirements of vehicular applications. However, a FC system combined with an energy storage system (ESS) can perform better for vehicle propulsion as considering several points. As the additional ESS can fulfill the transient power demand fluctuations, the FC system can be downsized to fit the base power demand without facing peak loads. Besides, braking energy can be recovered by the ESS. Interfacing of traction drive requirements with characteristics and modes of operation of on-board generation units and ESSs calls for suitable power electronic converter configuration. In this paper, a FC/UC hybrid vehicular power system using a multi-input converter-based power interface is proposed. The applied power interface topology ensures the active power sharing and DC link voltage stabilization for the hybrid vehicular system. The mathematical and electrical models of the hybrid vehicular system are developed in detail and simulated using MATLAB (registered) , Simulink (registered) and SimPowerSystems (registered) environments.

TRNSYS HYBRID wind diesel PV simulator

Energy Technology Data Exchange (ETDEWEB)

Quinlan, P.J.A.; Mitchell, J.W.; Klein, S.A.; Beckman, W.A.; Blair, N.J. [Univ. of Wisconsin, Madison, WI (United States)

1996-12-31

The Solar Energy Laboratory (SEL) has developed a wind diesel PV hybrid systems simulator, UW-HYBRID 1.0, an application of the TRNSYS 14.2 time-series simulation environment. An AC/DC bus links up to five diesels and wind turbine models, along with PV modules, a battery bank, and an AC/DC converter. Multiple units can be selected. PV system simulations include solar angle and peak power tracking options. Weather data are Typical Meteorological Year data, parametrically generated synthesized data, or external data files. PV performance simulations rely on long-standing SEL-developed algorithms. Loads data are read as scalable time series. Diesel simulations include estimated fuel-use and waste heat output, and are dispatched using a least-cost of fuel strategy. Wind system simulations include varying air density, wind shear and wake effects. Time step duration is user-selectable. UW-HYBRID 1.0 runs in Windows{reg_sign}, with TRNSED providing a customizable user interface. 12 refs., 6 figs.

Optoelectronics Interfaces for Power Converters

Directory of Open Access Journals (Sweden)

Ovidiu Neamtu

2009-05-01

Full Text Available The most important issue interface is galvanicseparation between the signal part and the power board.Standards in the field have increased continuouslyelectro-security requirements on the rigidity of thedielectric and insulation resistance. Recommendations forclassical solutions require the use of galvanic separationoptoelectronics devices. Interfacing with a PC or DSP -controller is a target of interposition optical signals viathe power hardware commands.

Open-Switch Fault Detection Method of a Back-to-Back Converter Using NPC Topology for Wind Turbine Systems

DEFF Research Database (Denmark)

Lee, June-Seok; Lee, Kyo_Beum; Blaabjerg, Frede

2015-01-01

system can break down in the worst case scenario. To improve the reliability of WTG systems, an open-switch fault detection method for back-to-back converters using the NPC topology is required. This study analyzes effects of inner and outer open-switch faults of the NPC rectifier and inverter......In wind turbine generation (WTG) systems, a back-to-back converter with a neutral-point-clamped (NPC) topology is widely used because this topology has more advantages than a conventional two-level topology, particularly when operating at high power. There are 12 switches in the NPC topology....... An open-switch fault in the NPC rectifier of the back-to-back converter leads to the distortion of the input current and torque vibration in the system. Additionally, an open-switch fault in the NPC inverter of the back-to-back converter causes the distortion of the output current. Furthermore, the WTG...

Oxidation of monolayers of partly converted dimethoxy-substituted poly(p-phenylenevinylene) precursor polymers at the air-water interface

NARCIS (Netherlands)

Hagting, J.G.; Schouten, A.J.; Hagting, A

2000-01-01

We observed that the poly(p-phenylenevinylene) units in Langmuir monolayers of partly converted dimethoxy-substituted poly(p-phenylenevinylene) precursor polymers oxidize at the air-water interface. This reaction even happened in the dark and therefore can not be attributed to a photooxygenation

Coupling modeling and analysis of a wind energy converter

Directory of Open Access Journals (Sweden)

Jie-jie Li

2016-06-01

Full Text Available In this article, the numerical simulation of a 2.0-MW wind energy converter coupling is achieved by three-dimensional computer-aided design modeling technique and finite element method. The static performances and the buckling characteristics of the diaphragm coupling are investigated. The diaphragm coupling is divided into three substructures, namely, torque input end, the middle section, and the torque output end. Considering the assembly and contact conditions, the simulation analysis for stress responses of the diaphragm coupling is carried out. The buckling factor and buckling mode of the diaphragms are obtained, and the geometric parameters of the diaphragms are optimized according to their buckling characteristics. The relationship between the pretightening force of the bolts, which tighten the friction flange and the friction plate, and the sliding torque is given by an empirical formula. The reasonable ranges of the pretightening force and tighten torque of the bolts are recommended. The fatigue analysis of the diaphragms is completed, and the results show that the diaphragms are competent to the designed life of the diaphragm coupling.

Development of a graphical user interface and graphics display for the WIND system

International Nuclear Information System (INIS)

O'Steen, B.L.; Fast, J.D.; Suire, B.S.

1992-01-01

An advanced graphical user interface (GUI) and improved graphics for transport calculations have been developed for the Weather Information and Display System (WINDS). Two WINDS transport codes, Area Evac and 2DPUF, have been ported from their original VAX/VMS environment to a UNIX operating system and reconfigured to take advantage of the new graphics capability. A developmental prototype of this software is now available on a UNIX based IBM 340 workstation in the Dose Assessment Center (DAC). Automatic transfer of meteorological data from the WINDS VAX computers to the IBM workstation in the DAC has been implemented. This includes both regional National Weather Service (NWS) data and SRS tower data. The above developments fulfill a FY 1993 DOE milestone

Back-to-back three-level converter controlled by a novel space-vector hysteresis current control for wind conversion systems

Energy Technology Data Exchange (ETDEWEB)

Ghennam, Tarak [Laboratoire d' Electronique de Puissance (LEP), UER: Electrotechnique, Ecole Militaire Polytechnique d' Alger, BP 17, Bordj EL Bahri, Alger (Algeria); Berkouk, El-Madjid [Laboratoire de Commande des Processus (LCP), Ecole Nationale Polytechnique d' Alger, BP 182, 10 avenue Hassen Badi, 16200 el Harrach (Algeria)

2010-04-15

In this paper, a novel space-vector hysteresis current control (SVHCC) is proposed for a back-to-back three-level converter which is used as an electronic interface in a wind conversion system. The proposed SVHCC controls the active and reactive powers delivered to the grid by the doubly fed induction machine (DFIM) through the control of its rotor currents. In addition, it controls the neutral point voltage by using the redundant inverter switching states. The three rotor current errors are gathered into a single space-vector quantity. The magnitude of the error vector is limited within boundary areas of a square shape. The control scheme is based firstly on the detection of the area and sector in which the vector tip of the current error can be located. Then, an appropriate voltage vector among the 27 voltage vectors of the three-level voltage source inverter (VSI) is applied to push the error vector towards the hysteresis boundaries. Simple look-up tables are required for the area and sector detection, and also for vector selection. The performance of the proposed control technique has been verified by simulations. (author)

Real time implementation and control validation of the wind energy conversion system

Science.gov (United States)

Sattar, Adnan

The purpose of the thesis is to analyze dynamic and transient characteristics of wind energy conversion systems including the stability issues in real time environment using the Real Time Digital Simulator (RTDS). There are different power system simulation tools available in the market. Real time digital simulator (RTDS) is one of the powerful tools among those. RTDS simulator has a Graphical User Interface called RSCAD which contains detail component model library for both power system and control relevant analysis. The hardware is based upon the digital signal processors mounted in the racks. RTDS simulator has the advantage of interfacing the real world signals from the external devices, hence used to test the protection and control system equipments. Dynamic and transient characteristics of the fixed and variable speed wind turbine generating systems (WTGSs) are analyzed, in this thesis. Static Synchronous Compensator (STATCOM) as a flexible ac transmission system (FACTS) device is used to enhance the fault ride through (FRT) capability of the fixed speed wind farm. Two level voltage source converter based STATCOM is modeled in both VSC small time-step and VSC large time-step of RTDS. The simulation results of the RTDS model system are compared with the off-line EMTP software i.e. PSCAD/EMTDC. A new operational scheme for a MW class grid-connected variable speed wind turbine driven permanent magnet synchronous generator (VSWT-PMSG) is developed. VSWT-PMSG uses fully controlled frequency converters for the grid interfacing and thus have the ability to control the real and reactive powers simultaneously. Frequency converters are modeled in the VSC small time-step of the RTDS and three phase realistic grid is adopted with RSCAD simulation through the use of optical analogue digital converter (OADC) card of the RTDS. Steady state and LVRT characteristics are carried out to validate the proposed operational scheme. Simulation results show good agreement with real

Miniature horizontal axis wind turbine system for multipurpose application

International Nuclear Information System (INIS)

Xu, F.J.; Yuan, F.G.; Hu, J.Z.; Qiu, Y.P.

2014-01-01

A MWT (miniature wind turbine) has received great attention recently for powering WISP (Wireless Intelligent Sensor Platform). In this study, two MHAWTs (miniature horizontal axis wind turbines) with and without gear transmission were designed and fabricated. A physics-based model was proposed and the optimal load resistances of the MHAWTs were predicted. The open circuit voltages, output powers and net efficiencies were measured under various ambient winds and load resistances. The experimental results showed the optimal load resistances matched well with the predicted results; the MHAWT without gear obtained higher output power at the wind speed of 2 m/s to 6 m/s, while the geared MHAWT exhibited better performance at the wind speed higher than 6 m/s. In addition, a DCM (discontinuous conduction mode) buck-boost converter was adopted as an interface circuit to maximize the charging power from MHAWTs to rechargeable batteries, exhibiting maximum efficiencies above 85%. The charging power reached about 8 mW and 36 mW at the wind speeds of 4 m/s and 6 m/s respectively, which indicated that the MHAWTs were capable for sufficient energy harvesting for powering low-power electronics continuously. - Highlights: • Performance of the miniature wind turbines with and without gears was compared. • The physics-based model was established and proved successfully. • The interface circuit with efficiency of more than 85% was designed

WINS. Market Simulation Tool for Facilitating Wind Energy Integration

Energy Technology Data Exchange (ETDEWEB)

Shahidehpour, Mohammad [Illinois Inst. of Technology, Chicago, IL (United States)

2012-10-30

Integrating 20% or more wind energy into the system and transmitting large sums of wind energy over long distances will require a decision making capability that can handle very large scale power systems with tens of thousands of buses and lines. There is a need to explore innovative analytical and implementation solutions for continuing reliable operations with the most economical integration of additional wind energy in power systems. A number of wind integration solution paths involve the adoption of new operating policies, dynamic scheduling of wind power across interties, pooling integration services, and adopting new transmission scheduling practices. Such practices can be examined by the decision tool developed by this project. This project developed a very efficient decision tool called Wind INtegration Simulator (WINS) and applied WINS to facilitate wind energy integration studies. WINS focused on augmenting the existing power utility capabilities to support collaborative planning, analysis, and wind integration project implementations. WINS also had the capability of simulating energy storage facilities so that feasibility studies of integrated wind energy system applications can be performed for systems with high wind energy penetrations. The development of WINS represents a major expansion of a very efficient decision tool called POwer Market Simulator (POMS), which was developed by IIT and has been used extensively for power system studies for decades. Specifically, WINS provides the following superiorities; (1) An integrated framework is included in WINS for the comprehensive modeling of DC transmission configurations, including mono-pole, bi-pole, tri-pole, back-to-back, and multi-terminal connection, as well as AC/DC converter models including current source converters (CSC) and voltage source converters (VSC); (2) An existing shortcoming of traditional decision tools for wind integration is the limited availability of user interface, i.e., decision

Power angle control of grid-connected voltage source converter in a wind energy application

Energy Technology Data Exchange (ETDEWEB)

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

1996-12-31

In this thesis, the connection of a voltage source converter to the grid in a wind energy application is examined. The possibility of using a cheap control system without grid current measurements, is investigated. The control method is based on controlling the voltage angle of the inverter, which governs the active power flow. The highest frequency of the power variation, coming from wind turbine, is approx. 5 Hz. Since the proposed control method easily can handle such power variations it is very well suited for wind turbine applications. The characteristics of the system depend on the DC-link capacitor, the grid filter inductance and resistance. Large values of the resistance damp the system well but increase the energy losses. A high inductance leads to a reduced harmonic level on the grid but makes the system slower. By using feed-forward of the generator/rectifier current signal, the performance is increased compared to an ordinary PI-control. Combining the Linear Quadratic (LQ) control method with Kalman filtered input signals, a robust control method with a good performance is obtained. The LQ controller controls both the phase displacement angle and the modulation index, resulting in higher bandwidth, and the typical power angle resonance at the grid frequency disappears. 22 refs, 109 figs, 14 tabs

Converter structure-based power loss and static thermal modeling of the press-pack IGBT-based three-level ANPC and HB VSCs applied to Multi-MW wind turbines

DEFF Research Database (Denmark)

Senturk, Osman Selcuk; Munk-Nielsen, Stig; Teodorescu, Remus

2010-01-01

and the switch thermal performance which is determined by the converter load profile and the converter structure. In this study, the converter-structure based power loss and thermal models are developed for the medium voltage full-scale 3LANPC- VSC and 3L-HB-VSC utilizing press-pack IGBT-diode pairs......The wind turbine converters demand high power density due to nacelle space limitation and high reliability due to high maintenance cost. Once the converter topology with the semiconductor switch technology is selected, the converter power density and reliability are dependent on the component count...

Multilevel push pull power converter

DEFF Research Database (Denmark)

2007-01-01

A power converter for converting an input voltage (Vin) into an output voltage (Vout), comprising a first supply potential and a second supply potential established by the input voltage, and at least one primary winding having two terminals, a center tap arranged between the two terminals and con...

Grid-connected wind and photovoltaic system

Science.gov (United States)

Devabakthuni, Sindhuja

The objective of this thesis is to design a grid connected wind and photovoltaic system. A new model of converter control was designed which maintains the voltage of the bus to grid as constant when combined system of solar and wind is connected to AC bus. The model is designed to track maximum power at each point irrespective of changes in irradiance, temperature and wind speed which affects the power supplied to grid. Solar power from the sun is not constant as it is affected by changes in irradiances and temperature. Even the wind power is affected by wind speed. A MPPT controller was designed for both systems. A boost converter is designed which uses the pulses from MPPT controller to boost the output. Wind system consists of wind turbine block from the MATLAB with a pitch angle controller to maintain optimum pitch angle. The output from wind turbine is connected to a permanent magnet synchronous generator. The unregulated DC output from the photovoltaic system is directly given to boost converter. The AC output from the wind system is given to an uncontrolled rectifier to get a unregulated DC output. The unregulated DC output goes to the boost converter. A voltage source inverter was designed which converts the rectified DC output from the boost converter to AC power. The inverter is designed to maintain constant AC bus voltage irrespective of the disturbances in the power supply. Photovoltaic and wind systems are individually designed for 5KW each in MATLAB-Simulink environment. In this thesis, the models were subjected to changes in irradiance, temperature and wind speed and the results were interpreted. The model was successful in tracking maximum at every instant and the AC bus voltage was maintained constant throughout the simulation.

Use of Three-Level Power Converters in Wind-Driven Permanent-Magnet Synchronous Generators with Unbalanced Loads

Directory of Open Access Journals (Sweden)

Ming-Hung Chen

2015-06-01

Full Text Available This paper describes the design and implementation of three-level power converters for wind-driven permanent-magnet synchronous generators with unbalanced loads. To increase voltage stress and reduce current harmonics in the electrical power generated by a wind generator, a three-phase, three-level rectifier is used. Because a synchronous rotating frame is used on the AC-input side, the use of a neutral-point-clamped controller is proposed to increase the power factor to unity and reduce current harmonics. Furthermore, a novel six-leg inverter is proposed for transferring energy from the DC voltage to a three-phase, four-wire AC source with a constant voltage and a constant frequency. The power converters also contain output transformers and filters for power buffering and filtering, respectively. All three output phase voltages are fed back to control the inverter output during load variations. A digital signal processor is used as the core control device for implementing a 1.5 kV, 75 kW drive system. Experimental data show that the power factor is successfully increased to unity and the total current harmonic distortion is 3.2% on the AC-input side. The entire system can attain an efficiency of 91%, and the voltage error between the upper and lower capacitors is approximately zero. Experimental results that confirm the high performance of the proposed system are presented.

Electric Generators and their Control for Large Wind Turbines

DEFF Research Database (Denmark)

Boldea, Ion; Tutelea, Lucian; Rallabandi, Vandana

2017-01-01

induction generator, the cage rotor induction generator, and the synchronous generator with DC or permanent magnet excitation. The operating principle, performance, optimal design, and the modeling and control of the machine-side converter for each kind of generator are adressed and evaluated. In view......The electric generator and its power electronics interface for wind turbines (WTs) have evolved rapidly toward higher reliability and reduced cost of energy in the last 40 years. This chapter describes the up-to-date electric generators existing in the wind power industry, namely, the doubly fed...... of the fact that individual power rating of WTs has increased to around 10 MW, generator design and control technologies required to reach this power rating are discussed....

Variable Speed Wind Turbine Based on Multiple Generators Drive-Train Configuration

DEFF Research Database (Denmark)

Deng, Fujin; Chen, Zhe

2010-01-01

A variable speed wind turbine is presented in this paper, where multiple permanent magnet synchronous generators (MPMSGs) drive-train configuration is employed in the wind turbine. A cascaded multilevel converter interface based on the MPMSGs is developed to synthesize a desired high ac sinusoidal...... output voltage, which could be directly connected to the grids. What is more, such arrangement has been made so that the output ac voltage having a selected phase angle difference among the stator windings of multiple generators. A phase angle shift strategy is proposed in this paper, which effectively...... reduce the fluctuation of the electromagnetic torque sum and results in a good performance for the MPMSGs structure. The simulation study is conducted using PSCAD/EMTDC, and the results verify the feasibility of this variable speed wind turbine based on multiple generators drive-train configuration....

Converter topologies for common mode voltage reduction

Energy Technology Data Exchange (ETDEWEB)

Rodriguez, Fernando

2017-11-21

An inverter includes a three-winding transformer, a DC-AC inverter electrically coupled to the first winding of the transformer, a cycloconverter electrically coupled to the second winding of the transformer, and an active filter electrically coupled to the third winding of the transformer. The DC-AC inverter is adapted to convert the input DC waveform to an AC waveform delivered to the transformer at the first winding. The cycloconverter is adapted to convert an AC waveform received at the second winding of the transformer to the output AC waveform having a grid frequency of the AC grid. The active filter is adapted to sink and source power with one or more energy storage devices based on a mismatch in power between the DC source and the AC grid. At least two of the DC-AC inverter, the cycloconverter, or the active filter are electrically coupled via a common reference electrical interconnect.

Converter Structure-Based Power Loss and Static Thermal Modeling of The Press-Pack IGBT Three-Level ANPC VSC Applied to Multi-MW Wind Turbines

DEFF Research Database (Denmark)

Senturk, Osman Selcuk; Helle, Lars; Munk-Nielsen, Stig

2011-01-01

performance, the converter structure-based power loss and thermal models are developed in this study for the medium-voltage (MV) three-level active neutral-point-clamped voltage source converter (3L-ANPC-VSC) utilizing 4500 V-1800 A press-pack insulated-gate bipolar transistor-diode pairs and interfacing a 6...

An Assessment of Converter Modelling Needs for Offshore Wind Power Plants Connected via VSC-HVDC Networks

DEFF Research Database (Denmark)

Glasdam, Jakob; Zeni, Lorenzo; Hjerrild, Jesper

2013-01-01

Modular multilevel cascaded converter (MMCC) based high voltage direct current (HVDC) transmission is technically superior to other technologies, especially in case of connection of offshore wind power plants (OWPPs). Modelling challenges are faced by OWPP developers, who are not acquainted...... with detailed information regarding the internal behaviour of such complex devices. This paper presents an investigation of the modelling requirements of the MMCC HVDC system, based on comparison between simulation results using a detailed HVDC representation in PSCAD/EMTDC and two less detailed models realised...

Tvindkraft: Implementing a 500 kW 21-IGBT-Based Frequency Converter for a 1.7 MW Wind Power Conversion System

DEFF Research Database (Denmark)

Gonzalez, Pablo Casado; Pang, Ying; Reigosa, Paula Diaz

2013-01-01

The 54-meter-high Tvindkraft windmill was built by a group of volunteers during 1975-1978, as an argument for renewable energy sources as well as an argument against nuclear power. At that time it was the world’s biggest windmill. So far, Tvindkraft has been running for 35 years, proving...... that a wellconstructed wind turbine is a sustainable approach to renewable energy utilization. This paper deals with the analysis, simulation, implementation and experimental testing of a new 500 kW 21- IGBT-based frequency converter that will run in parallel with the former 12-Thyristor-based frequency converter...... to fully utilize the capacity of the windmill. Simulations and experimental results are presented side-by-side to verify the proper functionalities of the frequency converter described in this paper....

Improved Design Methods for Robust Single- and Three-Phase ac-dc-ac Power Converters

DEFF Research Database (Denmark)

Qin, Zian

. The approaches for improving their performance, in terms of the voltage stress, efficiency, power density, cost, loss distribution, and temperature, will be studied. The structure of the thesis is as follows, Chapter 1 presents the introduction and motivation of the whole project as well as the background...... becomes a emerging challenge. Accordingly, installation of sustainable power generators like wind turbines and solar panels has experienced a large increase during the last decades. Meanwhile, power electronics converters, as interfaces in electrical system, are delivering approximately 80 % electricity...... back-to-back, and meanwhile improve the harmonics, control flexibility, and thermal distribution between the switches. Afterwards, active power decoupling methods for single-phase inverters or rectifiers that are similar to the single-phase ac-dc-ac converter, are studied in Chapter 4...

Control and Analysis for a Self-Excited Induction Generator for Wind Turbine and Electrolyzer Applications

Energy Technology Data Exchange (ETDEWEB)

Muljadi, Eduard [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Na, Woonki [California State University, Fresno; Leighty, Bill [The Leighty Foundation; Kim, Jonghoon [Chungnam National University

2017-12-14

Self-Excited Induction Generation(SEIG) is very rugged, simple, lightweight, and it is easy and inexpensive to implement, very simple to control, and requires a very little maintenance. In this variable-speed operation, the SEIG needs a power electronics interface to convert from the variable frequency output voltage of the generator to a DC output voltage for battery or other DC applications. In our study, a SEIG is connected to the power electronics interface such as diode rectifier and DC/DC converter and then an electrolyzer is connected as a final DC load for fuel cell applications. An equivalent circuit model for an electrolyzer is utilized for our application. The control and analysis for the proposed system is carried out by using PSCAD and MATLAB software. This study would be useful for designing and control analysis of power interface circuits for SEIG for a variable speed wind turbine generation with fuel cell applications before the actual implementation.

Performance and scalability of isolated DC-DC converter topologies in low voltage, high current applications

Energy Technology Data Exchange (ETDEWEB)

Vaisanen, V.

2012-07-01

Fuel cells are a promising alternative for clean and efficient energy production. A fuel cell is probably the most demanding of all distributed generation power sources. It resembles a solar cell in many ways, but sets strict limits to current ripple, common mode voltages and load variations. The typically low output voltage from the fuel cell stack needs to be boosted to a higher voltage level for grid interfacing. Due to the high electrical efficiency of the fuel cell, there is a need for high efficiency power converters, and in the case of low voltage, high current and galvanic isolation, the implementation of such converters is not a trivial task. This thesis presents galvanically isolated DC-DC converter topologies that have favorable characteristics for fuel cell usage and reviews the topologies from the viewpoint of electrical efficiency and cost efficiency. The focus is on evaluating the design issues when considering a single converter module having large current stresses. The dominating loss mechanism in low voltage, high current applications is conduction losses. In the case of MOSFETs, the conduction losses can be efficiently reduced by paralleling, but in the case of diodes, the effectiveness of paralleling depends strongly on the semiconductor material, diode parameters and output configuration. The transformer winding losses can be a major source of losses if the windings are not optimized according to the topology and the operating conditions. Transformer prototyping can be expensive and time consuming, and thus it is preferable to utilize various calculation methods during the design process in order to evaluate the performance of the transformer. This thesis reviews calculation methods for solid wire, litz wire and copper foil winding losses, and in order to evaluate the applicability of the methods, the calculations are compared against measurements and FEM simulations. By selecting a proper calculation method for each winding type, the winding

Model predictive control of wind energy conversion systems

CERN Document Server

Yaramasu, Venkata Narasimha R

2017-01-01

The authors provide a comprehensive analysis on the model predictive control of power converters employed in a wide variety of variable-speed wind energy conversion systems (WECS). The contents of this book includes an overview of wind energy system configurations, power converters for variable-speed WECS, digital control techniques, MPC, modeling of power converters and wind generators for MPC design. Other topics include the mapping of continuous-time models to discrete-time models by various exact, approximate, and quasi-exact discretization methods, modeling and control of wind turbine grid-side two-level and multilevel voltage source converters. The authors also focus on the MPC of several power converter configurations for full variable-speed permanent magnet synchronous generator based WECS, squirrel-cage induction generator based WECS, and semi-variable-speed doubly fed induction generator based WECS.

Thermal Analysis of Multilevel Grid-side Converters for 10-MW Wind turbines under Low-Voltage Ride Through

DEFF Research Database (Denmark)

Ma, Ke; Blaabjerg, Frede; Liserre, Marco

2013-01-01

in the power network and able to contribute to the grid recovery by injecting reactive current during grid faults. Consequently, the full-scale power converter solutions are becoming more and more popular to fulfill the growing challenges in the wind power application. Nevertheless, the loading of the power...... devices (particularly the diodes) under LVRT operation. Moreover, the three-level and five-level H-bridge topologies show more potential to reduce the inequality and level of device stress than the well-known three-level neutral point clamped topology....

The Study of Fuzzy Proportional Integral Controllers Based on Improved Particle Swarm Optimization for Permanent Magnet Direct Drive Wind Turbine Converters

Directory of Open Access Journals (Sweden)

Yancai Xiao

2016-05-01

Full Text Available In order to meet the requirements of high precision and fast response of permanent magnet direct drive (PMDD wind turbines, this paper proposes a fuzzy proportional integral (PI controller associated with a new control strategy for wind turbine converters. The purpose of the control strategy is to achieve the global optimization for the quantization factors, ke and kec, and scale factors, kup and kui, of the fuzzy PI controller by an improved particle swarm optimization (PSO method. Thus the advantages of the rapidity of the improved PSO and the robustness of the fuzzy controller can be fully applied in the control process. By conducting simulations for 2 MW PMDD wind turbines with Matlab/Simulink, the performance of the fuzzy PI controller based on the improved PSO is demonstrated to be obviously better than that of the PI controller or the fuzzy PI controller without using the improved PSO under the situation when the wind speed changes suddenly.

Converting Wind Energy to Ammonia at Lower Pressure

International Nuclear Information System (INIS)

Malmali, Mahdi; Reese, Michael; McCormick, Alon V.; Cussler, E. L.

2017-01-01

Renewable wind energy can be used to make ammonia. However, wind-generated ammonia costs about twice that made from a traditional fossil-fuel driven process. To reduce the production cost, we replace the conventional ammonia condensation with a selective absorber containing metal halides, e.g., calcium chloride, operating at near synthesis temperatures. With this reaction-absorption process, ammonia can be synthesized at 20 bar from air, water, and wind-generated electricity, with rates comparable to the conventional process running at 150–300 bar. In our reaction-absorption process, the rate of ammonia synthesis is now controlled not by the chemical reaction but largely by the pump used to recycle the unreacted gases. The results suggest an alternative route to distributed ammonia manufacture which can locally supply nitrogen fertilizer and also a method to capture stranded wind energy as a carbon-neutral liquid fuel.

Multilink DC Transmission for Offshore Wind Power Integration

DEFF Research Database (Denmark)

Craciun, Bogdan-Ionut; Silva, Rodrigo Da; Teodorescu, Remus

2012-01-01

analysis the Multi Terminal Direct Current (MTDC) operation and focuses on the sharing of active power produced by an offshore Wind Power Plant (WPP). The first objective was to model the system in PSCAD/EMTDC simulation software and then control structure tested under different situations. The second......The High Voltage Direct Current (HVDC) system gains much more flexibility on a basis of multi terminal operation. Having extra converters brings also new ideas in sharing the active power and one of the solutions is the use of virtual impedance correlated with a droop controller. This paper...... objective was to validate the simulation on a laboratory platform using 15 kW Voltage Source Converters (VSC) and a Real Time Interface (RTI). As a result, the power sharing is validated using such methodology and the influence in the parameters can be evaluated...

Power Quality Control and Design of Power Converter for Variable-Speed Wind Energy Conversion System with Permanent-Magnet Synchronous Generator

Directory of Open Access Journals (Sweden)

Yüksel Oğuz

2013-01-01

Full Text Available The control strategy and design of an AC/DC/AC IGBT-PMW power converter for PMSG-based variable-speed wind energy conversion systems (VSWECS operation in grid/load-connected mode are presented. VSWECS consists of a PMSG connected to a AC-DC IGBT-based PWM rectifier and a DC/AC IGBT-based PWM inverter with LCL filter. In VSWECS, AC/DC/AC power converter is employed to convert the variable frequency variable speed generator output to the fixed frequency fixed voltage grid. The DC/AC power conversion has been managed out using adaptive neurofuzzy controlled inverter located at the output of controlled AC/DC IGBT-based PWM rectifier. In this study, the dynamic performance and power quality of the proposed power converter connected to the grid/load by output LCL filter is focused on. Dynamic modeling and control of the VSWECS with the proposed power converter is performed by using MATLAB/Simulink. Simulation results show that the output voltage, power, and frequency of VSWECS reach to desirable operation values in a very short time. In addition, when PMSG based VSWECS works continuously with the 4.5 kHz switching frequency, the THD rate of voltage in the load terminal is 0.00672%.

Power quality control and design of power converter for variable-speed wind energy conversion system with permanent-magnet synchronous generator.

Science.gov (United States)

Oğuz, Yüksel; Güney, İrfan; Çalık, Hüseyin

2013-01-01

The control strategy and design of an AC/DC/AC IGBT-PMW power converter for PMSG-based variable-speed wind energy conversion systems (VSWECS) operation in grid/load-connected mode are presented. VSWECS consists of a PMSG connected to a AC-DC IGBT-based PWM rectifier and a DC/AC IGBT-based PWM inverter with LCL filter. In VSWECS, AC/DC/AC power converter is employed to convert the variable frequency variable speed generator output to the fixed frequency fixed voltage grid. The DC/AC power conversion has been managed out using adaptive neurofuzzy controlled inverter located at the output of controlled AC/DC IGBT-based PWM rectifier. In this study, the dynamic performance and power quality of the proposed power converter connected to the grid/load by output LCL filter is focused on. Dynamic modeling and control of the VSWECS with the proposed power converter is performed by using MATLAB/Simulink. Simulation results show that the output voltage, power, and frequency of VSWECS reach to desirable operation values in a very short time. In addition, when PMSG based VSWECS works continuously with the 4.5 kHz switching frequency, the THD rate of voltage in the load terminal is 0.00672%.

Optimal Allocation of Power-Electronic Interfaced Wind Turbines Using a Genetic Algorithm - Monte Carlo Hybrid Optimization Method

DEFF Research Database (Denmark)

Chen, Peiyuan; Siano, Pierluigi; Chen, Zhe

2010-01-01

determined by the wind resource and geographic conditions, the location of wind turbines in a power system network may significantly affect the distribution of power flow, power losses, etc. Furthermore, modern WTs with power-electronic interface have the capability of controlling reactive power output...... limit requirements. The method combines the Genetic Algorithm (GA), gradient-based constrained nonlinear optimization algorithm and sequential Monte Carlo simulation (MCS). The GA searches for the optimal locations and capacities of WTs. The gradient-based optimization finds the optimal power factor...... setting of WTs. The sequential MCS takes into account the stochastic behaviour of wind power generation and load. The proposed hybrid optimization method is demonstrated on an 11 kV 69-bus distribution system....

Fixed speed wind farm operation improvement using current-source converter based UPQC

International Nuclear Information System (INIS)

Ajami, Ali; Armaghan, Mehdi

2012-01-01

Highlights: ► Reactive power and voltage sag are compensated during grid side fault. ► Nonlinear model of UPQC is modified to a linear model. ► Using the CSI in proposed UPQC offers a number of distinct advantages. ► Pitch angle controller is used to obtain nominal power at high wind speeds. ► Optimal control method (LQR) is used to determine the optimal state feedback gains. - Abstract: In this paper, a current-source converter based unified power quality conditioner (UPQC) is used for the flexible integration of pitch controlled fixed speed wind generator (FSWG) to IEEE 13 node test feeder. During the normal operation, shunt compensator (SHUC) of the UPQC maintains a unity power factor condition at the Point of Common Coupling (PCC) and when a voltage sag occurs due to grid side fault the series compensator (SERC) of the UPQC injects appropriate deficit voltage to prevent disconnecting of the FSWG and the SHUC of the UPQC provides additional reactive power in fault during. The pitch angle is controlled in order to limit the generator output power to its nominal value for high wind speeds. The nonlinear model of the shunt compensator of the UPQC is modified to a linear model. The modeling technique is not based on the linearization of a set of nonlinear equations around an operating point. Instead, the power balance equation and a nonlinear input transformation are used to derive a linear model independent of the operating point. This model acts as the basis for the design of a decoupled state-feedback controller. The optimal control method linear quadratic regulator (LQR) is used to determine the optimal state-feedback gain matrix. The proposed control approach becomes a robust strategy that is able to keep regulation and stability even under extreme load power factor variations. The In-phase voltage injection method is used for the series compensator of the UPQC. The simulation results carried out by MATLAB/SIMULINK software show the performance of the

Three-port DC-DC converter with new integrated transformer for DC Distribution Systems

DEFF Research Database (Denmark)

Ouyang, Ziwei; Andersen, Michael A. E.

2014-01-01

A new integrated transformer for three-port dc-dc converter is proposed to overcome the power coupling effect existed in some known multiple inputs dc-dc converters. Orthogonal primary windings arrangement and in series connection of diagonal secondary Windings enables a fully power decoupling...

High Current Planar Transformer for Very High Efficiency Isolated Boost DC-DC Converters

DEFF Research Database (Denmark)

Pittini, Riccardo; Zhang, Zhe; Andersen, Michael A. E.

2014-01-01

This paper presents a design and optimization of a high current planar transformer for very high efficiency dc-dc isolated boost converters. The analysis considers different winding arrangements, including very high copper thickness windings. The analysis is focused on the winding ac-resistance a......This paper presents a design and optimization of a high current planar transformer for very high efficiency dc-dc isolated boost converters. The analysis considers different winding arrangements, including very high copper thickness windings. The analysis is focused on the winding ac......-resistance and transformer leakage inductance. Design and optimization procedures are validated based on an experimental prototype of a 6 kW dcdc isolated full bridge boost converter developed on fully planar magnetics. The prototype is rated at 30-80 V 0-80 A on the low voltage side and 700-800 V on the high voltage side...... with a peak efficiency of 97.8% at 80 V 3.5 kW. Results highlights that thick copper windings can provide good performance at low switching frequencies due to the high transformer filling factor. PCB windings can also provide very high efficiency if stacked in parallel utilizing the transformer winding window...

Impact of the Converter Control Strategies on the Drive Train of Wind Turbine during Voltage Dips

Directory of Open Access Journals (Sweden)

Fenglin Miao

2015-10-01

Full Text Available The impact of converter control strategies on the drive train of wind turbines during voltage dips is investigated in this paper using a full electromechanical model. Aerodynamics and tower vibration are taken into consideration by means of a simulation program, named FAST. Detailed gearbox and electrical subsystems are represented in MATLAB. The dynamic response of electromagnetic torque and its impact on the mechanical variables are the concern in this paper and the response of electrical variables is less discussed. From the mechanical aspects, the effect of rising power recovery speed and unsymmetrical voltage dips are analyzed on the basis of the dynamic response of the high-speed shaft (HSS. A comparison of the impact on the drive train is made for two converter control strategies during small voltage dips. Through the analysis of torque, speed and tower vibration, the results indicate that both power recovery speed and the sudden torque sag have a significant impact on drive trains, and the effects depend on the different control strategies. Moreover, resonance might be excited on the drive train by an unbalanced voltage.

A four channel time-to-digital converter ASIC with in-built calibration and SPI interface

International Nuclear Information System (INIS)

Hari Prasad, K.; Sukhwani, Menka; Saxena, Pooja; Chandratre, V.B.; Pithawa, C.K.

2014-01-01

A design of high resolution, wide dynamic range Time-to-Digital Converter (TDC) ASIC, implemented in 0.35 µm commercial CMOS technology is presented. The ASIC features four channel TDC with an in-built calibration and Serial Peripheral Interconnect (SPI) slave interface. The TDC is based on the vernier ring oscillator method in order to achieve both high resolution and wide dynamic range. This TDC ASIC is tested and found to have resolution of 127 ps (LSB), dynamic range of 1.8 µs and precision (σ) of 74 ps. The measured values of differential non-linearity (DNL) and integral non-linearity (INL) are 350 ps and 300 ps respectively

Advanced control of direct-driven PMSG generator in wind turbine system

Directory of Open Access Journals (Sweden)

Gajewski Piotr

2016-12-01

Full Text Available The paper presents the advanced control system of the wind energy conversion with a variable speed wind turbine. The considered system consists of a wind turbine with the permanent magnet synchronous generator (PMSG, machine side converter (MSC, grid side converter (GSC and control circuits. The mathematical models of a wind turbine system, the PMSG generator and converters have been described. The control algorithms of the converter systems based on the methods of vector control have been applied. In the advanced control system of the machine side converter the optimal MPPT control method has been used. Additionally the pitch control scheme is included in order to achieve the limitation of maximum power and to prevent mechanical damage of the wind turbine. In the control system of the grid side converter the control of active and reactive power has been applied with the application of Voltage Oriented Control (VOC. The performance of the considered wind energy system has been studied by digital simulation. The results of simulation studies confirmed the good effectiveness of the considered wind turbine system and very good performance of the proposed methods of vector control and control systems.

Load flow analysis for variable speed offshore wind farms

DEFF Research Database (Denmark)

Chen, Zhe; Zhao, Menghua; Blaabjerg, Frede

2009-01-01

factors such as the different wind farm configurations, the control of wind turbines and the power losses of pulse width modulation converters are considered. The DC/DC converter model is proposed and integrated into load flow algorithm by modifying the Jacobian matrix. Two iterative methods are proposed...... and integrated into the load flow algorithm: one takes into account the control strategy of converters and the other considers the power losses of converters. In addition, different types of variable speed wind turbine systems with different control methods are investigated. Finally, the method is demonstrated......A serial AC-DC integrated load flow algorithm for variable speed offshore wind farms is proposed. It divides the electrical system of a wind farm into several local networks, and different load flow methods are used for these local networks sequentially. This method is fast, more accurate, and many...

Multilevel Converter by Cascading Two-Level Three-Phase Voltage Source Converter

Directory of Open Access Journals (Sweden)

Abdullrahman A. Al-Shamma’a

2018-04-01

Full Text Available This paper proposes a topology using isolated, cascaded multilevel voltage source converters (VSCs and employing two-winding magnetic elements for high-power applications. The proposed topology synthesizes 6 two-level, three-phase VSCs, so the power capability of the presented converter is six times the capability of each VSC module. The characteristics of the proposed topology are demonstrated through analyzing its current relationships, voltage relationships and power capability in detail. The power rating is equally shared among the VSC modules without the need for a sharing algorithm; thus, the converter operates as a single three-phase VSC. The comparative analysis with classical neutral-point clamped, flying capacitor and cascaded H-bridge exhibits the superior features of fewer insulated gate bipolar transistors (IGBTs, capacitor requirement and fewer diodes. To validate the theoretical performance of the proposed converter, it is simulated in a MATLAB/Simulink environment and the results are experimentally demonstrated using a laboratory prototype.

Analysis of wear in organic and sintered friction materials used in small wind energy converters

Directory of Open Access Journals (Sweden)

Jorge Alberto Lewis Esswein Junior

2008-09-01

Full Text Available Wind energy converters of small size used in isolated units to generate electrical energy must present low maintenance cost to such facilities economically viable. The aspect to be analyzed in cost reduction is the brake system, since in isolated systems the use of brake is more frequent reducing the brake pads life time. This study aims at analyzing the wear behavior of some materials used in brake pads. An organic material was analyzed comparing it with a commercial brake pad, and the sintered material was developed and tested. The materials behaviors were evaluated in both wear and friction coefficient. The sintered samples were made by powder metallurgy. The composition was compacted at 550 MPa and sintered in a furnace with controlled atmosphere to avoid oxidation. Despite the different compositions of the two types of materials, they presented a very similar wear; however, the sintered material presented a higher friction coefficient. An adjustment in the braking system of the wind generator might be proposed to use the sintered brake pad, due to its higher friction coefficient. Consequently, the braking action becomes lower, reducing the wear rate of the material.

Multi-Megawatt-Scale Power-Hardware-in-the-Loop Interface for Testing Ancillary Grid Services by Converter-Coupled Generation: Preprint

Energy Technology Data Exchange (ETDEWEB)

Koralewicz, Przemyslaw J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Gevorgian, Vahan [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Wallen, Robert B [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2017-07-26

Power-hardware-in-the-loop (PHIL) is a simulation tool that can support electrical systems engineers in the development and experimental validation of novel, advanced control schemes that ensure the robustness and resiliency of electrical grids that have high penetrations of low-inertia variable renewable resources. With PHIL, the impact of the device under test on a generation or distribution system can be analyzed using a real-time simulator (RTS). PHIL allows for the interconnection of the RTS with a 7 megavolt ampere (MVA) power amplifier to test multi-megawatt renewable assets available at the National Wind Technology Center (NWTC). This paper addresses issues related to the development of a PHIL interface that allows testing hardware devices at actual scale. In particular, the novel PHIL interface algorithm and high-speed digital interface, which minimize the critical loop delay, are discussed.

Improving Power Converter Reliability

DEFF Research Database (Denmark)

Ghimire, Pramod; de Vega, Angel Ruiz; Beczkowski, Szymon

2014-01-01

of a high-power IGBT module during converter operation, which may play a vital role in improving the reliability of the power converters. The measured voltage is used to estimate the module average junction temperature of the high and low-voltage side of a half-bridge IGBT separately in every fundamental......The real-time junction temperature monitoring of a high-power insulated-gate bipolar transistor (IGBT) module is important to increase the overall reliability of power converters for industrial applications. This article proposes a new method to measure the on-state collector?emitter voltage...... is measured in a wind power converter at a low fundamental frequency. To illustrate more, the test method as well as the performance of the measurement circuit are also presented. This measurement is also useful to indicate failure mechanisms such as bond wire lift-off and solder layer degradation...

Wide Input Range Power Converters Using a Variable Turns Ratio Transformer

DEFF Research Database (Denmark)

Ouyang, Ziwei; Andersen, Michael A. E.

2016-01-01

A new integrated transformer with variable turns ratio is proposed to enable dc-dc converters operating over a wide input voltage range. The integrated transformer employs a new geometry of magnetic core with “four legs”, two primary windings with orthogonal arrangement, and “8” shape connection...... of diagonal secondary windings, in order to make the transformer turns ratio adjustable by controlling the phase between the two current excitations subjected to the two primary windings. Full-bridge boost dc-dc converter is employed with the proposed transformer to demonstrate the feasibility of the variable...

Utility-scale variable-speed wind turbines using a doubly-fed generator with a soft-switching power converter

Energy Technology Data Exchange (ETDEWEB)

Weigand, C.H.; Lauw, H.K.; Marckx, D.A. [Electronic Power Conditioning, Inc., Corvallis, OR (United States)

1996-12-31

Utility-scale wind turbines operating at variable RPM have been studied for a considerable period of time. Whereas the increase in energy output originally has been considered the principal benefit of variable-speed operation, the ability to tightly control the drive-train torque by electronic means is becoming another very important cost factor, especially for turbine ratings above 500 kilowatts. This cost benefit becomes even more significant as optimum turbine ratings today are approaching (and surpassing) 1 Megawatt. Having identified the benefits for the turbine, the designer is confronted with the task of finding the most cost-effective variable-speed generation system which allows him to make use of the benefits, yet does not introduce well-known electrical problems associated with state-of-the-art variable-speed generator controls, such as drastically reduced generator winding life, excessive harmonics on the utility, and poor utility power factor. This paper will indicate that for high-power (> 500 kW), utility-scale wind turbines a doubly-fed generator system in connection with a soft-switching resonant power converter is the least-cost variable-speed generation system offering all of the desired benefits, yet avoids the introduction of the potential electrical problems stated above. 3 refs., 3 figs., 1 tab.

Analysis of series resonant converter with series-parallel connection

Science.gov (United States)

Lin, Bor-Ren; Huang, Chien-Lan

2011-02-01

In this study, a parallel inductor-inductor-capacitor (LLC) resonant converter series-connected on the primary side and parallel-connected on the secondary side is presented for server power supply systems. Based on series resonant behaviour, the power metal-oxide-semiconductor field-effect transistors are turned on at zero voltage switching and the rectifier diodes are turned off at zero current switching. Thus, the switching losses on the power semiconductors are reduced. In the proposed converter, the primary windings of the two LLC converters are connected in series. Thus, the two converters have the same primary currents to ensure that they can supply the balance load current. On the output side, two LLC converters are connected in parallel to share the load current and to reduce the current stress on the secondary windings and the rectifier diodes. In this article, the principle of operation, steady-state analysis and design considerations of the proposed converter are provided and discussed. Experiments with a laboratory prototype with a 24 V/21 A output for server power supply were performed to verify the effectiveness of the proposed converter.

Optimized Integrated Harmonic Filter Inductor for Dual-Converter-Fed Open-End Transformer Topology

DEFF Research Database (Denmark)

Gohil, Ghanshyamsinh Vijaysinh; Bede, Lorand; Teodorescu, Remus

2017-01-01

Many high power converter systems are often connected to the medium voltage network using a step-up transformer. In such systems, the converter-side windings of the transformer can be configured as an open-end and multi-level voltage waveforms can be achieved by feeding these open-end windings from...

Impedance-Based Stability Analysis in Grid Interconnection Impact Study Owing to the Increased Adoption of Converter-Interfaced Generators

Directory of Open Access Journals (Sweden)

Youngho Cho

2017-09-01

Full Text Available This study investigates the emerging harmonic stability concerns to be addressed by grid planners in generation interconnection studies, owing to the increased adoption of renewable energy resources connected to the grid via power electronic converters. The wideband and high-frequency electromagnetic transient (EMT characteristics of these converter-interfaced generators (CIGs and their interaction with the grid impedance are not accurately captured in the typical dynamic studies conducted by grid planners. This paper thus identifies the desired components to be studied and subsequently develops a practical process for integrating a new CIG into a grid with the existing CIGs. The steps of this process are as follows: the impedance equation of a CIG using its control dynamics and an interface filter to the grid, for example, an LCL filter (inductor-capacitor-inductor type, is developed; an equivalent impedance model including the existing CIGs nearby and the grid observed from the point of common coupling are derived; the system stability for credible operating scenarios is assessed. Detailed EMT simulations validate the accuracy of the impedance models and stability assessment for various connection scenarios. By complementing the conventional EMT simulation studies, the proposed analytical approach enables grid planners to identify critical design parameters for seamlessly integrating a new CIG and ensuring the reliability of the grid.

Impact of the interfaces for wind and wave modeling - interpretation using COAWST, SAR and point measurements

DEFF Research Database (Denmark)

Air and sea interacts, where winds generate waves and waves affect the winds. This topic is ever relevant for offshore functions such as shipping, portal routines, wind farm operation and maintenance. In a coupled modeling system, the atmospheric modeling and the wave modeling interfere with each...... use the stress directly, thus avoiding the uncertainties caused by parameterizations. This study examines the efficiency of the wave impact transfer to the atmospheric modeling through the two types of interfaces, roughness length and stress, through the coupled......-ocean-atmosphere-wave-sediment-transport (COAWST) modeling system. The roughness length has been calculated using seven schemes (Charnock, Fan, Oost, Drennen, Liu, Andreas, Taylor-Yelland). The stress approach is applied through a wave boundary layer model in SWAN. The experiments are done to a case where the Synthetic Aperture Radar (SAR) image...

Wind Energy Conversion Systems Technology and Trends

CERN Document Server

2012-01-01

Wind Energy Conversion System covers the technological progress of wind energy conversion systems, along with potential future trends. It includes recently developed wind energy conversion systems such as multi-converter operation of variable-speed wind generators, lightning protection schemes, voltage flicker mitigation and prediction schemes for advanced control of wind generators. Modeling and control strategies of variable speed wind generators are discussed, together with the frequency converter topologies suitable for grid integration. Wind Energy Conversion System also describes offshore farm technologies including multi-terminal topology and space-based wind observation schemes, as well as both AC and DC based wind farm topologies. The stability and reliability of wind farms are discussed, and grid integration issues are examined in the context of the most recent industry guidelines. Wind power smoothing, one of the big challenges for transmission system operators, is a particular focus. Fault ride th...

Five-Phase Five-Level Open-Winding/Star-Winding Inverter Drive for Low-Voltage/High-Current Applications

DEFF Research Database (Denmark)

Padmanaban, Sanjeevi Kumar; Blaabjerg, Frede; Wheeler, Patrick

2016-01-01

This paper work proposed a five-phase five-level open-/star-winding multilevel AC converter suitable for low-voltage/high-current applications. Modular converter consists of classical two-level five-phase voltage source inverter (VSI) with slight reconfiguration to serve as a multilevel converter...... for open-/star-winding loads. Elaborately, per phase of the VSI is built with one additional bi-directional switch (MOSFET/IGBT) and all five legs links to the neutral through two capacitors. The structure allows multilevel generation to five-level output with greater potential for fault tolerability under...

Sequence Domain Harmonic Modeling of Type-IV Wind Turbines

DEFF Research Database (Denmark)

Guest, Emerson; Jensen, Kim Høj; Rasmussen, Tonny Wederberg

2017-01-01

-sampled pulsewidth modulation and an analysis of converter generated voltage harmonics due to compensated dead-time. The decoupling capabilities of the proposed the SD harmonic model are verified through a power quality (PQ) assessment of a 3MW Type-IV wind turbine. The assessment shows that the magnitude and phase...... of low-order odd converter generated voltage harmonics are dependent on the converter operating point and the phase of the fundamental component of converter current respectively. The SD harmonic model can be used to make PQ assessments of Type-IV wind turbines or incorporated into harmonic load flows...... for computation of PQ in wind power plants....

Fatigue and Serviceability Limit State Model Basis for Assessment of Offshore Wind Energy Converters

DEFF Research Database (Denmark)

Thöns, Sebastian; Faber, M. H.; Rücker, W.

2012-01-01

, a probabilistic model is derived on the basis of literature review and measurement data from a prototype Multibrid M5000 support structure. The sensitivity study is based on the calculation of a nonlinear coefficient of correlation in conjunction with predetermined designs of experiments. This is conducted......This paper develops the models for the structural performance of the loading and probabilistic characterization for the fatigue and the serviceability limit states for the support structure of offshore wind energy converters. These models and a sensitivity study are part of a risk based assessment...... as the starting point for the development of the structural performance and loading models. With these models introduced in detail, several modeling aspects for both limit states are analyzed. This includes analyses of the influence on the hot spot stresses by applying a contact formulation for the pile guide...

Remote power supply by wind/diesel/battery systems - operational experience and economy

International Nuclear Information System (INIS)

Kniehl, R.; Cramer, G.; Toenges, K.H.

1995-01-01

To continuously supply remote villages and settlements not connected to the public grid with electric power is an ambitious technical task considering ecological and economical points of view. The German company SMA has developed a modular supply system as a solution for this task in the range of 30 kW to 5 MW. Meanwhile more than 20 applications of these 'Intelligent Power Systems (IPS)' have proved their technical reliability and economical competitiveness worldwide under different, and also extreme environmental conditions. Actually it is the first commercially available advanced Wind/Diesel/Battery System for remote area electrification. The modular autonomous electric supply systems realized by SMA basically consist of two or more diesel power sets, battery storage with converter, a rotating phaseshifter, and an optional number of wind turbines. All modules are coupled on the 3-phase AC system grid and run in various parallel configurations depending on the wind speed and the consumer power demand. The control system operates fully automatical and offers a very user-friendly graphical interface. This advanced system control also contains a remote control and operating data output via modem and telephone line. SMA and CES have considerable experience with Wind/Diesel/Battery Systems for more than eight years. In many cases wind energy converters in the power range of 30 to 40 kW were used, but it is also possible to use larger wind turbines (e.g. 250 kW). In the following the system technology is described in detail, experience of different system sizes in several countries of application is presented, and economical analyses for power supply by IPS are given in comparison to a conventional fully diesel power supply. (author)

Remote power supply by wind/diesel/battery systems - operational experience and economy

Energy Technology Data Exchange (ETDEWEB)

Kniehl, R [CES - Consulting and Engineering Services, Heidelberg (Germany); Cramer, G; Toenges, K H [SMA Regelsysteme GmbH, Niestetal (Germany)

1996-12-31

To continuously supply remote villages and settlements not connected to the public grid with electric power is an ambitious technical task considering ecological and economical points of view. The German company SMA has developed a modular supply system as a solution for this task in the range of 30 kW to 5 MW. Meanwhile more than 20 applications of these `Intelligent Power Systems (IPS)` have proved their technical reliability and economical competitiveness worldwide under different, and also extreme environmental conditions. Actually it is the first commercially available advanced Wind/Diesel/Battery System for remote area electrification. The modular autonomous electric supply systems realized by SMA basically consist of two or more diesel power sets, battery storage with converter, a rotating phaseshifter, and an optional number of wind turbines. All modules are coupled on the 3-phase AC system grid and run in various parallel configurations depending on the wind speed and the consumer power demand. The control system operates fully automatical and offers a very user-friendly graphical interface. This advanced system control also contains a remote control and operating data output via modem and telephone line. SMA and CES have considerable experience with Wind/Diesel/Battery Systems for more than eight years. In many cases wind energy converters in the power range of 30 to 40 kW were used, but it is also possible to use larger wind turbines (e.g. 250 kW). In the following the system technology is described in detail, experience of different system sizes in several countries of application is presented, and economical analyses for power supply by IPS are given in comparison to a conventional fully diesel power supply. (author)

Remote power supply by wind/diesel/battery systems - operational experience and economy

Energy Technology Data Exchange (ETDEWEB)

Kniehl, R. [CES - Consulting and Engineering Services, Heidelberg (Germany); Cramer, G.; Toenges, K.H. [SMA Regelsysteme GmbH, Niestetal (Germany)

1995-12-31

To continuously supply remote villages and settlements not connected to the public grid with electric power is an ambitious technical task considering ecological and economical points of view. The German company SMA has developed a modular supply system as a solution for this task in the range of 30 kW to 5 MW. Meanwhile more than 20 applications of these `Intelligent Power Systems (IPS)` have proved their technical reliability and economical competitiveness worldwide under different, and also extreme environmental conditions. Actually it is the first commercially available advanced Wind/Diesel/Battery System for remote area electrification. The modular autonomous electric supply systems realized by SMA basically consist of two or more diesel power sets, battery storage with converter, a rotating phaseshifter, and an optional number of wind turbines. All modules are coupled on the 3-phase AC system grid and run in various parallel configurations depending on the wind speed and the consumer power demand. The control system operates fully automatical and offers a very user-friendly graphical interface. This advanced system control also contains a remote control and operating data output via modem and telephone line. SMA and CES have considerable experience with Wind/Diesel/Battery Systems for more than eight years. In many cases wind energy converters in the power range of 30 to 40 kW were used, but it is also possible to use larger wind turbines (e.g. 250 kW). In the following the system technology is described in detail, experience of different system sizes in several countries of application is presented, and economical analyses for power supply by IPS are given in comparison to a conventional fully diesel power supply. (author)

Hydrogen Gas Production in a Stand-Alone Wind Farm

Directory of Open Access Journals (Sweden)

M. Naziry Kordkandy

2017-04-01

Full Text Available This paper is analyzing the operation of a stand-alone wind farm with variable speed turbines, permanent magnet synchronous generators (PMSG and a system for converting wind energy during wind speed variations. On this paper, the design and modeling of a wind system which uses PMSG’s to provide the required power of a hydrogen gas electrolyzer system, is discussed. This wind farm consists of three wind turbines, boost DC-DC converters, diode full bridge rectifiers, permanent magnet synchronous generators, MPPT control and a hydrogen gas electrolyzer system. The MPPT controller based on fuzzy logic is designed to adjust the duty ratio of the boost DC-DC converters to absorb maximum power. The proposed fuzzy logic controller assimilates, with (PSF MPPT algorithm which generally used to absorb maximum power from paralleled wind turbines and stores it in form of hydrogen gas. The system is modeled and its behavior is studied using the MATLAB software.

Offshore wind farm harmonic resonance analysis, part I : Converter harmonic model

NARCIS (Netherlands)

Sun, Yin; De Jong, Erik; Cobben, J. F.G.; Cuk, Vladimir

2017-01-01

Offshore wind power technology has matured significantly and now directly competes with conventional and onshore wind power generation. Thanks to continuous technological developments and significant cost reduction, offshore wind power is closing the gap with the onshore wind power about the

A Unified Voltage Harmonic Control Strategy for Coordinated Compensation with VCM and CCM Converters

DEFF Research Database (Denmark)

Zhao, Xin; Meng, Lexuan; Xie, Chuan

2018-01-01

-controlled mode (VCM) and current-controlled mode (CCM), need to cooperatively provide the compensation function. Aiming at this objective, this paper proposes a unified voltage harmonic mitigation strategy for VCM and CCM converters with high harmonic current sharing accuracy. Another advantage of the proposal......Harmonics have been considered as one of the major issues in modern power grids. Considering the high penetration level of power electronic converter interfaced distributed generators (DGs), it is of interest to provide ancillary services through DG interfacing converters, such as harmonic...... compensation. In case of that, multiple DG interfacing converters are utilized to compensate harmonics, and the compensation effort should be properly shared among these converters. However, it is rarely considered in existing literatures that converters operating in different modes, such as voltage...

Y-Source Boost DC/DC Converter for Distributed Generation

DEFF Research Database (Denmark)

Siwakoti, Yam P.; Loh, Poh Chiang; Blaabjerg, Frede

2015-01-01

This paper introduces a versatile Y-source boost dc/dc converter intended for distributed power generation, where high gain is often demanded. The proposed converter uses a Y-source impedance network realized with a tightly coupled three-winding inductor for high voltage boosting that is presently...

Effect of wind generation system types on Micro-Grid (MG) fault performance during both standalone and grid connected modes

International Nuclear Information System (INIS)

Kamel, Rashad M.

2014-01-01

Highlights: • This paper evaluated the effects of different wind system types on fault performance of Micro-Grid. • Both standalone and grid connected modes are considered. • The MG earthing system configuration is taken in consideration. - Abstract: Recently, there are three wind generation (WG) system types. The first type is called Fixed Speed Wind Generation (FSWG) system, which employs squirrel cage induction generators. Double Fed Induction Generator (DFIG) is utilized in the second type. The third type is called Full Converter Wind Generation (FCWG) system, which is interfaced with Micro-Grid (MG) through a back to back converter. During fault occurrence, each WG has its performance and characteristics which are determined by the generator physical characteristics and the MG earthing system configuration. For some WG types, the fault current depends also on the control algorithm of the power converter. The main target of this paper is to investigate and estimate how the fault performance of MG during both standalone and grid-connected modes is influenced by the type of WG. It is found during standalone mode that the type of the employed WG has a dominant impact on the MG performance under fault disturbance. On the contrary, the type of the employed WG has a negligible effect on the MG fault performance during grid-connected mode. This is because the main grid contributes most of the fault current. Effects of earthing system type on MG performance are highlighted

Modeling and Control of Grid Side Converter in Wind Power Generation System Based on Synchronous VFDPC with PLL

DEFF Research Database (Denmark)

Guo, Yougui; Zeng, Ping; Li, Lijuan

2011-01-01

Virtual flux oriented direct power control (VFDPC) is combined space vector modulation (SVM) with PI of DC-link voltage, active power and reactive power to control the grid side converter in wind power generation system in this paper. VFDPC has reached good performances with PLL (phase lock loop......, LCL filter, transformer grid, and control parts, such as PI controllers of DC-link voltage, active power, reactive power, and SVM, and so on. The simulation results have verified that the control strategy is feasible to fit for control of gird currents, active power, reactive power and DC-link voltage...

Advanced Load Alleviation for Wind Turbines using Adaptive Trailing Edge Flaps: Sensoring and Control

DEFF Research Database (Denmark)

Andersen, Peter Bjørn

The purpose of wind turbines and their predecessors the windmill, is to convert the energy in the wind to usable energy forms. Whereas windmills of the past focused on the conversion of wind power to torque for grinding, pumping and winching, modern wind turbines convert the wind energy...... into electric power. They do so through incorporation of generators, which convert mechanical torque into electricity. Wind turbines are designed to keep the overall cost per produced Kilo Watt hour as low as possible. One way of improving the performance and lifetime of the wind turbine is through active flow...

High Voltage Power Converter for Large Wind Turbine

DEFF Research Database (Denmark)

Sztykiel, Michal

and the feeder cable sections, careful investigation for the relay selective operation has been made, which distinguishes ground faults located at the wind turbine terminals from faults within the protected cables. The obtained results from the computer simulations in EMTDC/PSCAD software show, that the best...... also for different grounding schemes, which impact is the result of the removed step-up transformer. Finally, the ground fault detection scheme for feeder cable system is proposed - with the usage of current differential relay. Due to lack of the galvanic separation between the wind turbines...

Performance comparison of wind park configurations

Energy Technology Data Exchange (ETDEWEB)

Lundberg, Stefan

2003-07-01

In this report, layouts of various large-scale wind parks, both AC as well as DC, are investigated. Loss modelling of the wind park components as well as calculations of the energy capture of the turbines using various electrical systems are performed, and the energy production cost of the various park configurations is determined. It was found that from an energy capture point of view, the difference in energy production between various wind turbine systems is very small. In addition, a study of the suitability of various DC/DC-converters is made. Three DC/DC-converters, Boost, Full Bridge and Full Bridge Isolated Boost, are found to be interesting candidates as the 'transformer' component in potential DC-based wind parks. Of all the investigated wind park configurations, the wind park with the series connected DC wind turbines seems to have the best potential to give the lowest energy production cost, if the transmission distance is longer then 10-20 km.

A review of Indirect Matrix Converter Topologies

Directory of Open Access Journals (Sweden)

Salem Rahmani

2015-08-01

Full Text Available Abstract—Matrix Converter (MC is a modern direct AC/AC electrical power converter without dc-link capacitor. MC is operated in four quadrant, assuring a control of the output voltage, amplitude and frequency. The matrix converter has recently attracted significant attention among researchers and it has become increasing attractive for applications of wind energy conversion, military power supplies, induction motor drives, etc. Recently, different MC topologies have been proposed and developed which have their own advantages and disadvantages. Matrix converter can be classified as direct and indirect structures. The direct one has been elaborated in previous work. In this paper the indirect MCs are reviewed. Different characteristics of the indirect MC topologies are mentioned to show the strengths and weaknesses of such converter topologies.

A Survey of Control Issues in PMSG-Based Small Wind-Turbine Systems

DEFF Research Database (Denmark)

Orlando, Natalia Angela; Liserre, Marco; Mastromauro, Rosa Anna

2013-01-01

/position estimation, pitch control, braking chopper control, dc/dc converter control, and grid converter control. Specific issues for small wind-turbines arise in the wind energy extraction optimization and limitation and in the innovative concept of “universal” wind-turbine operation, that leads these system...... generators directly connected to the grid, while recently permanent magnet synchronous generators (PMSG) with power converter, either partially or fully controlled, became popular. This paper reviews the control issues related to these small wind-turbine systems: generator torque control, speed...

A TECHNIQUE OF EXPERIMENTAL INVESTIGATIONS OF LINEAR IMPULSE ELECTROMECHANICAL CONVERTERS

Directory of Open Access Journals (Sweden)

V.F. Bolyukh

2017-04-01

Full Text Available Purpose. Development of a technique of experimental studies linear pulse electromechanical converters parameters, which are used as shock-power devices and electromechanical accelerators, and comparing the experimental results with the calculated indices obtained using the mathematical model. Methodology. Method of experimental investigations of linear electromechanical converter is that the electrical parameters are recorded simultaneously (inductor winding current and mechanical parameters characterizing the power and speed indicators of the joke with actuator. Power indicators are primarily important for shock-power devices, and high velocity - for electromechanical accelerators. Power indices were investigated using piezoelectric sensors, a system of strain sensors, pressure pulsation sensor and high-speed videorecording. Velocity indicators were investigated using a resistive movement sensor which allows to record character of the armature movement with actuating element in each moment. Results. The technique of experimental research, which is the simultaneous recording of electrical and mechanical power and velocity parameters of the linear electromechanical converter pulse, is developed. In the converter as a shock-power device power indicators are recorded using a piezoelectric transducer, strain sensors system, pressure pulsation sensor and high-speed video. The parameters of the inductor winding current pulse, the time lag of mechanical processes in relation to the time of occurrence of the inductor winding current, the average speed of the joke, the magnitude and momentum of electrodynamics forces acting on the plate strikes are experimentally determined. In the converter as an electromechanical accelerator velocity performance recorded using resistive displacement sensors. It is shown that electromechanical converter processes have complex spatial-temporal character. The experimental results are in good agreement with the calculated

Smart Wind Turbine : Analysis and Autonomous Flap

NARCIS (Netherlands)

Bernhammer, L.O.

2015-01-01

Wind turbines convert kinetic energy of the wind into electrical energy. Unfortunately, this process is everything but constant, as the wind source shows large fluctuations with high and low frequencies. This turbulence, together with the wind shear and yawed inflow, excites the turbine structure,

Magnetic integration of the harmonic filter inductor for dual-converter fed open-end transformer topology

DEFF Research Database (Denmark)

Gohil, Ghanshyamsinh Vijaysinh; Bede, Lorand; Teodorescu, Remus

2016-01-01

Many high power converter systems are often connected to the medium voltage network using a step-up transformer. In such systems, the converter-side windings of the transformer can be configured as an open-end and multi-level voltage waveforms can be achieved by feeding these open-end windings from...

Electromechanical converters for electric vehicles

Science.gov (United States)

Ambros, T.; Burduniuc, M.; Deaconu, S. I.; Rujanschi, N.

2018-01-01

The paper presents the analysis of various constructive schemes of synchronous electromechanical converters with permanent magnets fixed on the rotor and asynchronous with the short-circuit rotor. Various electrical stator winding schemes have also been compared, demonstrating the efficiency of copper utilization in toroidal windings. The electromagnetic calculus of the axial machine has particularities compared to the cylindrical machine, in the paper is presented the method of correlating the geometry of the cylindrical and axial machines. In this case the method and recommendations used in the design of such machines may be used.

Grid-friendly wind power systems based on the synchronverter technology

International Nuclear Information System (INIS)

Zhong, Qing-Chang; Ma, Zhenyu; Ming, Wen-Long; Konstantopoulos, George C.

2015-01-01

Highlights: • A grid-friendly wind power system that uses the synchronverter technology is proposed. • Both the rotor-side and the grid-side converters act as synchronverters. • The complete generator–motor–generator system improves the performance under grid faults. • Real-time digital simulation results verify the effectiveness of the proposed method. - Abstract: Back-to-back PWM converters are becoming a realistic alternative to conventional converters in high-power wind power applications. In this paper, a control strategy based on the synchronverter technology is proposed for back-to-back PWM converters. Both converters are run as synchronverters, which are mathematically equivalent to the conventional synchronous generators. The rotor-side converter is responsible for maintaining the DC link voltage and the grid-side converter is responsible for the maximum power point tracking (MPPT). As the two converters are operated using the synchronverter technology, the formed wind power system becomes more friendly to the grid. Extensive real-time digital simulation results are presented to verify the effectiveness of the proposed method under normal operation and grid-fault scenarios

Wind Energy

Energy Technology Data Exchange (ETDEWEB)

Beurskens, H.J.M. [SET Analysis, Kievitlaan 26, 1742 AD Schagen (Netherlands); Brand, A.J. [Energy research Centre of the Netherlands ECN, Unit Wind Energy, P.O. Box 1, 1755 ZG Petten (Netherlands)

2013-02-15

Over the years, wind energy has become a major source of renewable energy worldwide. The present chapter addresses the wind resource, which is available for exploitation for large-scale electricity production, and its specific physical properties. Furthermore, the technical options available to convert the energy of the air flow into mechanical energy and electricity are described. Specific problems of large-scale integration of wind energy into the grid as well as the present and future market developments are described in this chapter. Finally, environmental aspects are discussed briefly.

Wind tower service lift

Science.gov (United States)

Oliphant, David; Quilter, Jared; Andersen, Todd; Conroy, Thomas

2011-09-13

An apparatus used for maintaining a wind tower structure wherein the wind tower structure may have a plurality of legs and may be configured to support a wind turbine above the ground in a better position to interface with winds. The lift structure may be configured for carrying objects and have a guide system and drive system for mechanically communicating with a primary cable, rail or other first elongate member attached to the wind tower structure. The drive system and guide system may transmit forces that move the lift relative to the cable and thereby relative to the wind tower structure. A control interface may be included for controlling the amount and direction of the power into the guide system and drive system thereby causing the guide system and drive system to move the lift relative to said first elongate member such that said lift moves relative to said wind tower structure.

Integration of Magnetic Components in a Step-Up Converter for Fuel Cell

DEFF Research Database (Denmark)

Klimczak, Pawel; Munk-Nielsen, Stig

2009-01-01

converter is a critical part. The input voltage of the converter decreases while the output power increases. It creates challenges in design of the converter's magnetic components. Scope of this paper is integration of the dc inductor and the transformer on a single core. Such integration improve...... utilization of the core and windings. It leads to size reduction of the converter....

Wind-driven stand-alone DFIG with battery and pumped hydro ...

Indian Academy of Sciences (India)

Renewable energy electric conversion system; induction generators; wind power generation; energy storage; power converters. ... converter, (ii) wide speed operation of wind-driven DFIG, (iii) reduced battery capacity, (iv) high energy storage using PHSP and (v) availability of continuous power to the isolated loads.

A Feedback Passivation Design for DC Microgrid and Its DC/DC Converters

Directory of Open Access Journals (Sweden)

Feifan Ji

2016-12-01

Full Text Available There are difficulties in analyzing the stability of microgrids since they are located on various network structures. However, considering that the network often consists of passive elements, the passivity theory is applied in this paper to solve the above-mentioned problem. It has been formerly shown that when the network is weakly strictly positive real (WSPR, the DC microgrid is stable if all interfaces between the microgrid and converters are made to be passive, which is called interface passivity. Then, the feedback passivation method is proposed for the controller design of various DC–DC converters to achieve the interface passivity. The interface passivity is different from the passivity of closed-loop systems on which the passivity based control (PBC concentrates. The feedback passivation design is detailed for typical buck converters and boost converters in terms of conditions that the controller parameters should satisfy. The theoretical results are verified by a hardware-in-loop real-time labotray (RTLab simulation of a DC microgrid with four generators.

Dynamic modeling of wind turbine based axial flux permanent magnetic synchronous generator connected to the grid with switch reduced converter

Directory of Open Access Journals (Sweden)

Ali Reza Dehghanzadeh

2018-03-01

Full Text Available This paper studies the power electronic converters for grid connection of axial flux permanent magnetic synchronous generators (AFPMSG based variable speed wind turbine. In this paper, a new variable speed wind turbine with AFPMSG and Z-source inverter is proposed to improve number of switches and topology reliability. Besides, dynamic modeling of AFPMSG is presented to analyze grid connection of the proposed topology. The Z-source inverter controls maximum power point tracking (MPPT and delivering power to the grid. Therefore other DC–DC chopper is not required to control the rectified output voltage of generator in view of MPPT. As a result, the proposed topology requires less power electronic switches and the suggested system is more reliable against short circuit. The ability of proposed energy conversion system with AFPMSG is validated with simulation results and experimental results using PCI-1716 data acquisition system.

Reactive power influence on the thermal cycling of multi-MW wind power inverter

DEFF Research Database (Denmark)

Ma, Ke; Liserre, Marco; Blaabjerg, Frede

2012-01-01

converter system are first presented at different wind speeds. Furthermore, the interaction between paralleled converter systems in a wind park is also considered and analyzed. By controlling the reactive power circulated among paralleled converters, a new concept is then proposed to stabilize the thermal...

Wind Penetration with different wind turbine technologies in a weak grid

International Nuclear Information System (INIS)

Santos Fuentefria, Ariel; Castro Fernandez, Miguel A.; Martínez García, Antonio

2012-01-01

The insertion of wind energy into electric network may provoke stability problems due to stochastic character of wind. The variation in the wind causes voltage variation in the Point of Common Coupling (PCC). In a weakest system that variation is high. Another important factor is wind turbine technology. The use of grid-connected fixed speed wind generator introduces a great consumption of reactive power that can be compensated using different devices as capacitors bank or static var compensator (SVC or STATCOM). In the other hand the variable speed wind turbine have an electronic converter to control the reactive consumption to maintain the PCC voltage more stable. In this paper a comparison between the different types of wind turbines technology is show. It's analyzing the impact in wind power limit for different wind turbine technologies in a weak system. (author)

Understanding delta-sigma data converters

CERN Document Server

Pavan, Shanti; Temes, Gabor C

2017-01-01

This new edition introduces novel analysis and design techniques for delta-sigma (ΔΣ) converters in physical and conceptual terms, and includes new chapters that explore developments in the field over the last decade. This book explains the principles and operation of delta-sigma analog-to-digital converters (ADCs) in physical and conceptual terms in accordance with the most recent developments in the field. The interest of ΔΣ converter designers has shifted significantly over the past decade, due to many new applications for data converters at the far ends of the frequency spectrum. Continuous-time delta-sigma A/D converters with GHz clocks, of both lowpass and bandpass types, are required for wireless applications. At the other extreme, multiplexed ADCs with very narrow (sometimes 10 Hz wide) signal bandwidths, but very high accuracy are needed in the interfaces of biomedical and environmental sensors. To reflect the changing eeds of designers, the second edition includes significant new material on bo...

Probabilistic Harmonic Modeling of Wind Power Plants

DEFF Research Database (Denmark)

Guest, Emerson; Jensen, Kim H.; Rasmussen, Tonny Wederberg

2017-01-01

A probabilistic sequence domain (SD) harmonic model of a grid-connected voltage-source converter is used to estimate harmonic emissions in a wind power plant (WPP) comprised of Type-IV wind turbines. The SD representation naturally partitioned converter generated voltage harmonics into those...... with deterministic phase and those with probabilistic phase. A case study performed on a string of ten 3MW, Type-IV wind turbines implemented in PSCAD was used to verify the probabilistic SD harmonic model. The probabilistic SD harmonic model can be employed in the planning phase of WPP projects to assess harmonic...

Realization and control of a wind turbine connected to the grid by using PMSG

International Nuclear Information System (INIS)

Dahbi, Abdeldjalil; Hachemi, Mabrouk; Nait-Said, Nasreddine; Nait-Said, Mohamed-Said

2014-01-01

Highlights: • Realization and control of a wind turbine. • Control of the system. • Injection to grid. - Abstract: This paper studies the control of a variable-speed wind turbine using the permanent magnet synchronous generator (PMSG) driven by a wind turbine emulator. The wind turbine is realized by imposing the wind profile on emulator to behave as the real wind turbine when it receives the same wind profile. This wind turbine is connected to the grid by means of a two back-to-back voltage-fed pulse width-modulation (PWM) converters to interface the generator and the grid. This paper has three main objectives, the first is realization of the wind turbine emulator, the second is extracting and exploiting the maximum power from the wind, the third is feeding the grid by high-power and good electrical energy quality; to achieve that, we applied the strategies of maximum power point tracking (MPPT) using optimal torque control which allows the PMSG to operate at an optimal speed. The inverter is used for delivering power to the grid, controlled in a way to deliver only the active power into the grid, thus we have unit power factor. DC-link voltage is also controlled by the inverter. This paper shows the dynamic performances of the complete system by its simulation using Matlab Simulink. Experimental results has verified and validated the wind turbine emulator and the efficiency of MPPT control method using a variable wind profile

A Review of Power Electronics for Wind Power

Institute of Scientific and Technical Information of China (English)

Zhe CHEN

2011-01-01

The paper reviews the power electronic applications for wind energy systems.Main wind turbine systems with different generators and power electronic converters are described.The electrical topologies of wind farms with power electronic conversion are discussed.Power electronic applications for improving the performance of wind turbines and wind farms in power systems have been illustrated.

SWITCH MODE PULSE WIDTH MODULATED DC-DC CONVERTER WITH MULTIPLE POWER TRANSFORMERS

DEFF Research Database (Denmark)

2009-01-01

A switch mode pulse width modulated DC-DC power converter comprises at least one first electronic circuit on a input side (1) and a second electronic circuit on a output side (2). The input side (1) and the output side (2) are coupled via at least two power transformers (T1, T2). Each power...... transformer (T1, T2) comprises a first winding (T1a, T2a) arranged in a input side converter stage (3, 4) on the input side (1) and a second winding (T1 b, T2b) arranged in a output side converter stage (5) on the output side (2), and each of the windings (T1a, T1 b, T2a, T2b) has a first end and a second end....... The first electronic circuit comprises terminals (AO, A1) for connecting a source or a load, at least one energy storage inductor (L) coupled in series with at least one of the first windings (T1a, T2a) of the power transformers (T1, T2), and for each power transformer (T1, T2), an arrangement of switches...

Harmonic Resonances in Wind Power Plants

DEFF Research Database (Denmark)

Fernandez, Francisco Daniel Freijedo; Chaudhary, Sanjay; Teodorescu, Remus

2015-01-01

This work reviews the state-of-the-art in the field of harmonic resonance problems in Wind Power Plants (WPPs). Firstly, a generic WPP is modeled according to the equivalent circuits of its passive and active components. Main focus is put on modeling active components, i.e. the ones based on power...... converters. Subsequently, pros and cons of frequency and time domain analysis methods are outlined. The next sections are devoted to mitigation methods implemented in the power electronics converters. From the wind turbine perspective, different techniques to enhance the robustness of the controller...... are analyzed. Subsequently, the suitability for active damping of harmonics using STATCOM devices is assessed, with focus both on control techniques and power converter technologies....

Reducing Harmonic Instability and Resonance Problems in PMSG Based Wind Farms

DEFF Research Database (Denmark)

Ebrahimzadeh, Esmaeil; Blaabjerg, Frede; Wang, Xiongfei

2018-01-01

Unlike conventional power systems where harmonic resonances are coming from passive inductive and capacitive elements, large-scale power electronic systems like wind farms present a more complex system, where the fast dynamics of the power electronic converters may present an inductive or capacit......Unlike conventional power systems where harmonic resonances are coming from passive inductive and capacitive elements, large-scale power electronic systems like wind farms present a more complex system, where the fast dynamics of the power electronic converters may present an inductive...... or capacitive behavior. Therefore, the interactions between the fast controllers of the power converters and the passive elements may lead to harmonic instability and new resonances at various frequencies. This paper presents an optimum design technique for the Wind Turbine (WT) inner controllers in a PMSG...... based wind farm in order to reduce the number of resonances and to mitigate harmonic instability. In the approach, a PMSG based wind farm is modeled as a Multi-Input Multi-Output (MIMO) dynamic system by modeling the high bandwidth control loops of the power converters. Resonance frequencies...

A Review of Power Electronics for Wind Power

DEFF Research Database (Denmark)

Chen, Zhe

2011-01-01

The paper reviews the power electronic applications for wind energy systems. Main wind turbine systems with different generators and power electronic converters are described. The electrical topologies of wind farms with power electronic conversion are discussed. Power electronic applications...

Effect of Short-Circuit Faults in the Back-to-Back Power Electronic Converter and Rotor Terminals on the Operational Behavior of the Doubly-Fed Induction Generator Wind Energy Conversion System

Directory of Open Access Journals (Sweden)

Dimitrios G. Giaourakis

2015-02-01

Full Text Available This paper deals with the operational behavior of the Doubly-Fed Induction Generator Wind Energy Conversion System under power electronic converter and rotor terminals faulty conditions. More specifically, the effect of the short-circuit fault both in one IGBT of the back-to-back power electronic converter and in rotor phases on the overall system behavior has been investigated via simulation using a system of 2 MW. Finally, the consequences of these faults have been evaluated.

A novel proton exchange membrane fuel cell based power conversion system for telecom supply with genetic algorithm assisted intelligent interfacing converter

International Nuclear Information System (INIS)

Kaur, Rajvir; Krishnasamy, Vijayakumar; Muthusamy, Kaleeswari; Chinnamuthan, Periasamy

2017-01-01

Highlights: • Proton exchange membrane fuel cell based telecom tower supply is proposed. • The use of diesel generator is eliminated and battery size is reduced. • Boost converter based intelligent interfacing unit is implemented. • The genetic algorithm assisted controller is proposed for effective interfacing. • The controller is robust against input and output disturbance rejection. - Abstract: This paper presents the fuel cell based simple electric energy conversion system for supplying the telecommunication towers to reduce the operation and maintenance cost of telecom companies. The telecom industry is at the boom and is penetrating deep into remote rural areas having unreliable or no grid supply. The telecom industry is getting heavily dependent on a diesel generator set and battery bank as a backup for continuously supplying a base transceiver station of telecom towers. This excessive usage of backup supply resulted in increased operational expenditure, the unreliability of power supply and had become a threat to the environment. A significant development and concern of clean energy sources, proton exchange membrane fuel cell based supply for base transceiver station is proposed with intelligent interfacing unit. The necessity of the battery bank capacity is significantly reduced as compared with the earlier solutions. Further, a simple closed loop and genetic algorithm assisted controller is proposed for intelligent interfacing unit which consists of power electronic boost converter for power conditioning. The proposed genetic algorithm assisted controller would ensure the tight voltage regulation at the DC distribution bus of the base transceiver station. Also, it will provide the robust performance of the base transceiver station under telecom load variation and proton exchange membrane fuel cell output voltage fluctuations. The complete electric energy conversion system along with telecom loads is simulated in MATLAB/Simulink platform and

DFIG-based offshore wind power plant connected to a single VSC-HVDC operated at variable frequency: Energy yield assessment

International Nuclear Information System (INIS)

De-Prada-Gil, Mikel; Díaz-González, Francisco; Gomis-Bellmunt, Oriol; Sumper, Andreas

2015-01-01

The existence of HVDC (High Voltage Direct Current) transmission systems for remote offshore wind power plants allows devising novel wind plant concepts, which do not need to be synchronized with the main AC grid. This paper proposes an OWPP (offshore wind power plant) design based on variable speed wind turbines driven by DFIGs (doubly fed induction generators) with reduced power electronic converters connected to a single VSC-HVDC converter which operates at variable frequency and voltage within the collection grid. It is aimed to evaluate the influence of the power converter size and wind speed variability within the WPP on energy yield efficiency, as well as to develop a coordinated control between the VSC-HVDC converter and the individual back-to-back reduced power converters of each DFIG-based wind turbine in order to provide control capability for the wind power plant at a reduced cost. To maximise wind power generation by the OWPP, an optimum electrical frequency search algorithm for the VSC-HVDC converter is proposed. Both central wind power plant control level and local wind turbine control level are presented and the performance of the system is validated by means of simulations using MATLAB/Simulink ® . - Highlights: • Influence of converter size and wind speed variability on energy capture efficiency. • Coordinated control between a VSC-HVDC and DFIG WTs with reduced power converters. • Static and dynamic analysis of the performance of the implemented control scheme. • Optimal variable frequency operation to maximize WPP generation at a reduced cost

Reliability of Power Electronic Converter Systems

DEFF Research Database (Denmark)

-link capacitance in power electronic converter systems; wind turbine systems; smart control strategies for improved reliability of power electronics system; lifetime modelling; power module lifetime test and state monitoring; tools for performance and reliability analysis of power electronics systems; fault...... for advancing the reliability, availability, system robustness, and maintainability of PECS at different levels of complexity. Drawing on the experience of an international team of experts, this book explores the reliability of PECS covering topics including an introduction to reliability engineering in power...... electronic converter systems; anomaly detection and remaining-life prediction for power electronics; reliability of DC-link capacitors in power electronic converters; reliability of power electronics packaging; modeling for life-time prediction of power semiconductor modules; minimization of DC...

WindWaveFloat (WWF): Final Scientific Report

Energy Technology Data Exchange (ETDEWEB)

Weinstein, Alla; Roddier, Dominique; Banister, Kevin

2012-03-30

Principle Power Inc. and National Renewable Energy Lab (NREL) have completed a contract to assess the technical and economic feasibility of integrating wave energy converters into the WindFloat, resulting in a new concept called the WindWaveFloat (WWF). The concentration of several devices on one platform could offer a potential for both economic and operational advantages. Wind and wave energy converters can share the electrical cable and power transfer equipment to transport the electricity to shore. Access to multiple generation devices could be simplified, resulting in cost saving at the operational level. Overall capital costs may also be reduced, provided that the design of the foundation can be adapted to multiple devices with minimum modifications. Finally, the WindWaveFloat confers the ability to increase energy production from individual floating support structures, potentially leading to a reduction in levelized energy costs, an increase in the overall capacity factor, and greater stability of the electrical power delivered to the grid. The research conducted under this grant investigated the integration of several wave energy device types into the WindFloat platform. Several of the resulting system designs demonstrated technical feasibility, but the size and design constraints of the wave energy converters (technical and economic) make the WindWaveFloat concept economically unfeasible at this time. Not enough additional generation could be produced to make the additional expense associated with wave energy conversion integration into the WindFloat worthwhile.

Mission profile resolution effects on lifetime estimation of doubly-fed induction generator power converter

DEFF Research Database (Denmark)

Zhang, Guanguan; Zhou, Dao; Blaabjerg, Frede

2017-01-01

, and the corresponding thermal modeling of power semiconductors are discussed. Accordingly, effects of different mission profiles on the consumed lifetime of the power converter are evaluated. In the above three thermal cycles, the IGBT of the grid-side converter and the diode of the rotor-side converter are more...... fragile, and the total consumed lifetimes are higher. Moreover, the short-term thermal cycles with milliseconds resolution induce the unbalance of the lifetime between the diode and IGBT of the grid-side converter, while thermal cycles with hour, second, and millisecond resolution consumes the similar......In the wind energy generation system, mission profiles are complicated, which range from seconds to years. In order to estimate the consumed lifetime of the power converter, wind speed profiles with the time resolution of 1 hour, 1 second and 0.5 millisecond are studied in this paper...

A Technique for Mitigating Thermal Stress and Extending Life Cycle of Power Electronic Converters Used for Wind Turbines

Directory of Open Access Journals (Sweden)

Canras Batunlu

2015-11-01

Full Text Available Over the last two decades, various models have been developed to assess and improve the reliability of power electronic conversion systems (PECs with a focus on those used for wind turbines. However, only few studies have dealt with mitigating the PECs thermo-mechanical effects on their reliability taking into account variations in wind characteristics. This work critically investigates this issue and attempts to offer a mitigating technique by, first, developing realistic full scale (FS and partial scale (PS induction generator models combined with two level back-to-back PECs. Subsequently, deriving a driving algorithm, which reduces PEC’s operating temperature by controlling its switching patterns. The developed switching procedure ensures minimum temperature fluctuations by adapting the variable DC link and system’s frequency of operation. It was found for both FS and PS topologies, that the generator side converters have higher mean junction temperatures where the grid side ones have more fluctuations on their thermal profile. The FS and PS cycling temperatures were reduced by 12 °C and 5 °C, respectively. Moreover, this led to a significant improvement in stress; approximately 27 MPa stress reduction for the FS induction generator PEC.

A Review of the State of the Art of Power Electronics for Wind Turbines

DEFF Research Database (Denmark)

Chen, Zhe; Guerrero, Josep M.; Blaabjerg, Frede

2009-01-01

are summarized and the possible uses of power electronic converters with wind farms are shown. Finally, the possible methods of using the power electronic technology for improving wind turbine performance in power systems to meet the main grid connection requirements are discussed.......This paper reviews the power electronic applications for wind energy systems. Various wind turbine systems with different generators and power electronic converters are described, and different technical features are compared. The electrical topologies of wind farms with different wind turbines...

A New Application of the Multi-Resonant Zero-Current Switching Buck Converter: Analysis and Simulation in a PMSG Based WECS

Directory of Open Access Journals (Sweden)

Tiara Freitas

2015-09-01

Full Text Available A new application of the three-phase buck-resonant converter is presented in this paper. It is shown that the analyzed converter is suitable to operate as the rectifier stage in low power wind energy conversion systems (WECS based on permanent magnet synchronous generators (PMSG with variable wind speed. As main features, it presents a single controlled switch, simple implementation and control, and operates with a high power factor and low harmonic distortion over all wind speed ranges. The converter topology, its design equations and its operation are presented, as well as the simulation results of the PMSG based conversion system. From the analysis carried out in the paper it is concluded that the converter is indicated to be employed in distributed generation and hybrid systems where wind generation is associated with other sources.

Reactive power control methods for improved reliability of wind power inverters under wind speed variations

DEFF Research Database (Denmark)

Ma, Ke; Liserre, Marco; Blaabjerg, Frede

2012-01-01

method to relieve the thermal cycling of power switching devices under severe wind speed variations, by circulating reactive power among the parallel power converters in a WTS or among the WTS's in a wind park. The amount of reactive power is adjusted to limit the junction temperature fluctuation...

Advanced load alleviation for wind turbines using adaptive trailing edge flaps: Sensoring and control

Energy Technology Data Exchange (ETDEWEB)

Andersen, Peter Bjoern

2010-02-15

The purpose of wind turbines and their predecessors the windmill, is to convert the energy in the wind to usable energy forms. Whereas windmills of the past focused on the conversion of wind power to torque for grinding, pumping and winching, modern wind turbines convert the wind energy into electric power. They do so through incorporation of generators, which convert mechanical torque into electricity. Wind turbines are designed to keep the overall cost per produced Kilo Watt hour as low as possible. One way of improving the performance and lifetime of the wind turbine is through active flow control. Active control is often considered costly but if the lifespan of the components can be increased it could be justifiable. This thesis covers various aspects of 'smart control' such as control theory, sensoring, optimization, experiments and numerical modeling. (author)

Generators for gearless wind energy converters

Energy Technology Data Exchange (ETDEWEB)

Grauers, A. [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Electric Power Engineering

1996-12-01

This paper discusses some design alternatives for directly driven generators, and one specific generator type is investigated for a wide range of rated power. First, the specification for a directly driven generator is presented, then different design alternatives are discussed. A radial-flux permanent magnet generator for frequency converter connection has been chosen for a more detailed investigation. The design, optimization and performance of that generator type are presented. Generators from 30 kW to 3 MW are designed and compared with conventional four-pole generators with gear. It is found that a directly driven generator can be more efficient than a conventional generator and gear and have a rather small diameter and a low active weight. 8 refs, 7 figs, 2 tabs

A review on DC/DC converter architectures for power fuel cell applications

International Nuclear Information System (INIS)

Kolli, Abdelfatah; Gaillard, Arnaud; De Bernardinis, Alexandre; Bethoux, Olivier; Hissel, Daniel; Khatir, Zoubir

2015-01-01

Highlights: • Different DC/DC power converter topologies for Fuel Cell systems are presented. • Advantages and drawbacks of the DC/DC power converter topologies are detailed. • Wide-BandGap semiconductors are attractive candidates for design of converters. • Wide-BandGap semiconductors improve efficiency and thermal limits of converters. • Different semiconductor technologies are assessed. - Abstract: Fuel cell-based power sources are attractive devices. Through multi-stack architecture, they offer flexibility, reliability, and efficiency. Keys to accessing the market are simplifying its architecture and each components. These include, among others, the power converter enabling the output voltage regulation. This article focuses on this specific component. The present paper gives a comprehensive overview of the power converter interfaces potentially favorable for the automotive, railways, aircrafts and small stationary domains. First, with respect to the strategic development of a modular design, it defines the specifications of a basic interface. Second, it inventories the best architecture opportunities with respect to these requirements. Based on this study, it fully designs a basic module and points out the outstanding contribution of the new developed silicon carbide switch technology. In conclusion, this review article exhibits the importance of choosing the right power converter architecture and the related technology. In this context it is highlighted that the output power interface can be efficient, compact and modular. In addition, its features enable a thermal compatibility with many ways of integrating this component in the global fuel cell based power source.

Model-Based Fault Detection and Isolation of a Liquid-Cooled Frequency Converter on a Wind Turbine

DEFF Research Database (Denmark)

Li, Peng; Odgaard, Peter Fogh; Stoustrup, Jakob

2012-01-01

advanced fault detection and isolation schemes. In this paper, an observer-based fault detection and isolation method for the cooling system in a liquid-cooled frequency converter on a wind turbine which is built up in a scalar version in the laboratory is presented. A dynamic model of the scale cooling...... system is derived based on energy balance equation. A fault analysis is conducted to determine the severity and occurrence rate of possible component faults and their end effects in the cooling system. A method using unknown input observer is developed in order to detect and isolate the faults based...... on the developed dynamical model. The designed fault detection and isolation algorithm is applied on a set of measured experiment data in which different faults are artificially introduced to the scaled cooling system. The experimental results conclude that the different faults are successfully detected...

Wake Effects on Lifetime Distribution in DFIG-based Wind Farms

DEFF Research Database (Denmark)

Tian, Jie; Zhou, Dao; Su, Chi

2017-01-01

With the increasing size of the wind farms, the impact of the wake effect on the energy yields and lifetime consumption of wind turbine can no longer be neglected. In this paper, the affecting factors like the wind speed and wind direction are investigated in terms of the single wake and multiple...... wakes. As the power converter is the most fragile component among the turbine system, its lifetime estimation can be calculated seen from the thermal stress of the power semiconductor. On the basis of the relationship of the power converter in a 5 MW Doubly-Fed Induction Generator (DFIG) wind turbine...... system and the wind speed, the lifetime consumption of the individual turbine in a 10-turbine and an 80-turbine wind farms can be calculated by considering the real distributions of the wind speed and direction. It can be seen that there is significant lifetime difference among individual turbines...

Power-hardware-in-the-loop test of VSC-HVDC connection for off-shore wind power plants

Energy Technology Data Exchange (ETDEWEB)

Sharma, Ranjan [Siemens Wind Power A/S, Brande (Denmark); Technical Univ. of Denmark (Denmark). Center for Electric Technology; Cha, Seung T.; Wu, Qiuwei; Rasmussen, Tonny W.; Oestergaard, Jacob [Technical Univ. of Denmark (Denmark). Center for Electric Technology; Jensen, Kim H. [Siemens Wind Power A/S, Brande (Denmark)

2011-07-01

This paper present a power-hardware-in-the-loop (PHIL) test of an off-shore wind power plant (WPP) interconnected to the on-shore grid via a VSC-HVDC connection. The intention of the PHIL test is to verify the hardware interaction and the control co-ordination between the plant side VSC of the HVDC system and the wind turbines within the WPP in order to ensure smooth operation of the WPP under both normal and fault operating condition. The PHIL test platform is comprised of a real time digital simulator (RTDS), a Spitzenberger Spies three phase 7,5 kW power amplifier, a purpose built VSC and a DC chopper. The WPP is simulated in the RTDS as a single full-scale wind turbine. The simulated WPP interacts with the WPP side VSC through the power amplifier. The interface between the RTDS and the power amplifier is done via an analogue GTAO I/O card of the RTDS and the input channel of the amplifier. The amplifier scales up the voltages at the point of connection of the WPP in the RTDS to the voltage level for the WPP side VSC. The WPP side VSC converter is equipped with a DC chopper. The test results show the successful control coordination between the WPP and the plant side VSC converter of the HVDC connection of the WPP. (orig.)

Power control for wind turbines in weak grids: Concepts development

DEFF Research Database (Denmark)

Bindner, H.

1999-01-01

will make wind power more firm and possible to connect to weaker grids. So, when the concept is matured, theexpectation is that for certain wind power installations, the cost of the power control is paid back as added wind power capacity value and saved grid reinforcement costs. Different systems...... and analyze methods and technologies for making it viable to utilize more of the wind potential in remote areas. The suggestion is to develop a power control concept for wind turbines which will even out thepower fluctuations and make it possible to increase the wind energy penetration. The main options...... are to combine wind power with a pumped hydro power storage or with an AC/DC converter and battery storage. The AC/DC converter can either be an "add-on" typeor it can be designed as an integrated part of a variable speed wind turbine. The idea is that combining wind power with the power control concept...

A Root-Locus Design Methodology Derived from the Impedance/Admittance Stability Formulation and Its Application for LCL Grid-Connected Converters in Wind Turbines

DEFF Research Database (Denmark)

Freijedo Fernandez, Francisco Daniel; Diaz, Enrique Rodriguez; Golsorkhi, Mohammad

2017-01-01

This paper presents a systematic methodology for design and tuning of the current controller in LCL gridconnected converters for wind turbine applications. The design target is formulated as a minimization of the current loop dominant time constant, which is in accordance with standard design......, it has been also proved to be very suitable for system level studies in applications with a high penetration of renewable energy resources. The tuning methodology is as follows: firstly, the physical system is modelled in terms of the converter admittance and its equivalent grid impedance; then......, a sensitivity transfer function is derived, from which the closed-loop eigenvalues can be calculated; finally, the set of control gains that minimize the dominant time constant are obtained by direct search optimization. A case study that models the target system in a low power scale is provided...

Voltage-current characteristics of multiterminal HVDC-VSC for offshore wind farms

Energy Technology Data Exchange (ETDEWEB)

Gomis-Bellmunt, Oriol [Centre d' Innovacio Tecnologica en Convertidors Estatics i Accionaments (CITCEA-UPC), Universitat Politecnica de Catalunya UPC, Av. Diagonal, 647, Pl. 2., 08028 Barcelona (Spain); IREC Catalonia Institute for Energy Research, Barcelona (Spain); Liang, Jun; Ekanayake, Janaka; Jenkins, Nicholas [School of Engineering, Cardiff University, Queen' s Buildings, The Parade, Cardiff CF24 3AA, Wales (United Kingdom)

2011-02-15

Voltage-current characteristics and equilibrium points for the DC voltages of multiterminal HVDC systems using voltage source converters are discussed. The wind farm rectifiers and grid connected inverters are analyzed through their operating modes, governing equations and graphical characteristics. Using the converter equations and the HVDC grid conductance matrix the equilibrium voltages and currents are found. Case studies are presented considering wind power generation, loss of a converter and voltage sags in the AC grid. (author)

Gas tube-switched high voltage DC power converter

Science.gov (United States)

She, Xu; Bray, James William; Sommerer, Timothy John; Chokhawala, Rahul

2018-05-15

A direct current (DC)-DC converter includes a transformer and a gas tube-switched inverter circuit. The transformer includes a primary winding and a secondary winding. The gas tube-switched inverter circuit includes first and second inverter load terminals and first and second inverter input terminals. The first and second inverter load terminals are coupled to the primary winding. The first and second inverter input terminals are couplable to a DC node. The gas tube-switched inverter circuit further includes a plurality of gas tube switches respectively coupled between the first and second inverter load terminals and the first and second inverter input terminals. The plurality of gas tube switches is configured to operate to generate an alternating current (AC) voltage at the primary winding.

Modeling and Identification of Harmonic Instability Problems In Wind Farms

DEFF Research Database (Denmark)

Ebrahimzadeh, Esmaeil; Blaabjerg, Frede; Wang, Xiongfei

2016-01-01

In power electronics based power systems like wind farms, the interactions between the inner control systems of the power converters and the passive components may lead to high frequency oscillations, which can be called harmonic instability. In this paper, a simple methodology is presented...... to identify harmonic instability problems in wind farms, where many wind turbines, cables, transformers, capacitor banks, shunt reactors, etc, typically are located. This methodology introduces the wind farm as a Multi-Input Multi-Outpur (MIMO) control system, where the linearized models of fast inner control....../EMTDC software environment for a 400-MW wind farm. The proposed analytical analysis method and time-domain simulation results show that both dynamics of the power electronic converter and the parameters of the passive component can effect on the wind farm stability....

Smart Wind Turbine: Analysis and Autonomous Flap

OpenAIRE

Bernhammer, L.O.

2015-01-01

Wind turbines convert kinetic energy of the wind into electrical energy. Unfortunately, this process is everything but constant, as the wind source shows large fluctuations with high and low frequencies. This turbulence, together with the wind shear and yawed inflow, excites the turbine structure, thereby driving the loads and the design of turbines in general and blades in particular. In response to this, several control mechanisms have been applied to wind turbines since the generation of s...

Soft switching PWM isolated boost converter for fuel cell application

Energy Technology Data Exchange (ETDEWEB)

Rezaei, M.; Adib, E. [Isfahan Univ. of Technology, Isfahan (Iran, Islamic Republic of)

2009-07-01

This presentation introduced a newly developed soft switching, isolated boost type converter for fuel cell applications. With a simple PWM control circuit, the converter achieves zero voltage switching the main switch. Since the auxiliary circuit is soft switched, the converter can operate at high powers which make it suitable for fuel cell applications. In particular, the converter is suitable for the interface of fuel cell and inverters because of its high voltage gain and isolation between input and output sources. In addition, the input current of the converter (current drained from the fuel cell) is almost constant since it is a boost type converter. The converter was analyzed and the simulation results validate the theoretical analysis.

Direct Drive Synchronous Machine Models for Stability Assessment of Wind Farms

Energy Technology Data Exchange (ETDEWEB)

Poeller, Markus; Achilles, Sebastian [DIgSILENT GmbH, Gomaringen (Germany)

2003-11-01

The increasing size of wind farms requires power system stability analysis including dynamic wind generator models. For turbines above 1MW doubly-fed induction machines are the most widely used concept. However, especially in Germany, direct-drive wind generators based on converter-driven synchronous generator concepts have reached considerable market penetration. This paper presents converter driven synchronous generator models of various order that can be used for simulating transients and dynamics in a very wide time range.

Wind generator with electronic variable-speed drives

Energy Technology Data Exchange (ETDEWEB)

David, A.; Buchheit, N.; Jakobsen, H.

1996-12-31

Variable speed drives have been inserted between the network and the generator on certain recent wind power facilities. They have the following advantages: the drive allows the wind generator to operate at low speed with a significant reduction in acoustic noise, an important point if the facilities are sited near populated areas; the drive optimizes energy transfer, providing a gain of 4 to 10 %; the drive can possibly replace certain mechanical parts (the starting system and it in some cases, the reduction gear); the drive not only provides better transient management in relation to the network for less mechanical stress on the wind generator, it is also able to control reactive power. One commercial drive design sold by several manufacturers has already been installed on several wind generators with outputs of between 150 and 600 kw. In addition, such a solution is extremely well suited to mixed renewable energy systems. This design uses two inverse rectifier type converters and can therefore exchange energy in both directions. The equivalent drive with a single IGBT converter on the motor side and a diode converter on the network side is the solution most widely adopted throughout industry (with more than 50, 000 units installed in France per year). It still remains to be seen whether such a solution could be profitable in wind generator application (since the cost of the drive is quite high). This technical analysis is more destined for the converter-machine assembly specialists and is presented in this document, paying particular attention as it does to the modelling of the `wind energy - generator - drive - network` assembly, the associated drive command and control strategies and the simulations obtained during various transients. A 7.5 kW test bed has been installed in the Laboratoire d`Electronique de Puissance de Clamart, enabling tests to be carried out which emulate the operation of a wind generator.

Reduced-Capacity Inrush Current Suppressor Using a Matrix Converter in a Wind Power Generation System with Squirrel-Cage Induction Machines

Directory of Open Access Journals (Sweden)

Sho Shibata

2016-03-01

Full Text Available This paper describes the reduced capacity of the inrush current suppressor using a matrix converter (MC in a large-capacity wind power generation system (WPGS with two squirrel-cage induction machines (SCIMs. These SCIMs are switched over depending on the wind speed. The input side of the MC is connected to the source in parallel. The output side of the MC is connected in series with the SCIM through matching transformers. The modulation method of the MC used is direct duty ratio pulse width modulation. The reference output voltage of the MC is decided by multiplying the SCIM current with the variable control gain. Therefore, the MC performs as resistors for the inrush current. Digital computer simulation is implemented to confirm the validity and practicability of the proposed inrush current suppressor using PSCAD/EMTDC (power system computer-aided design/electromagnetic transients including DC. Furthermore, the equivalent resistance of the MC is decided by the relationship between the equivalent resistance and the capacity of the MC. Simulation results demonstrate that the proposed inrush current suppressor can suppress the inrush current perfectly.

Digitally-controlled PC-interfaced Boost Converter for Educational Purposes

DEFF Research Database (Denmark)

Ljusev, Petar; Andersen, Michael A. E.

2004-01-01

This paper describes implementation of a simple digital PID control algorithm for a boost converter using a cheap fixed-point 8-bit microcontroller. Serial communication to a PC server program is established for easier downloading of compensator parameters and current and voltage waveform...

Four Quadrants Integrated Transformers for Dual-input Isolated DC-DC Converters

DEFF Research Database (Denmark)

Ouyang, Ziwei; Zhang, Zhe; Andersen, Michael A. E.

2012-01-01

A common limitation of power coupling effect in some known multiple-input dc-dc converters has been addressed in many literatures. In order to overcome this limitation, a new concept for decoupling the primary windings in the integrated multiple-winding transformers based on 3-dimensional (3D...... perpendicular primary windings, a name of “four quadrants integrated transformers” (FQIT) is therefore given to the proposed construction. Since the two primary windings are uncoupled, the FQIT allows the two input power stages to transfer the energy into the output load simultaneously or at any...

Converter applications and their influence on large electrical machines

CERN Document Server

Drubel, Oliver

2013-01-01

Converter driven applications are applied in more and more processes. Almost any installed wind-farm, ship drives, steel mills, several boiler feed water pumps, extruder and many other applications operate much more efficient and economic in case of variable speed solutions. The boundary conditions for a motor or generator will change, if it is supplied by a converter. An electrical machine, which is operated by a converter, can no longer be regarded as an independent component, but is embedded in a system consisting of converter and machine. This book gives an overview of existing converter designs for large electrical machines. Methods for the appropriate calculation of machine phenomena, which are implied by converters are derived in the power range above 500kVA. It is shown how due to the converter inherent higher voltage harmonics and pulse frequencies special phenomena are caused inside the machine which can be the reason for malfunction. It is demonstrated that additional losses create additional tempe...

Fault Tolerant Control of Wind Turbines

DEFF Research Database (Denmark)

Odgaard, Peter Fogh; Stoustrup, Jakob; Kinnaert, Michel

2013-01-01

This paper presents a test benchmark model for the evaluation of fault detection and accommodation schemes. This benchmark model deals with the wind turbine on a system level, and it includes sensor, actuator, and system faults, namely faults in the pitch system, the drive train, the generator......, and the converter system. Since it is a system-level model, converter and pitch system models are simplified because these are controlled by internal controllers working at higher frequencies than the system model. The model represents a three-bladed pitch-controlled variable-speed wind turbine with a nominal power...

High Efficiency Boost Converter with Three State Switching Cell

DEFF Research Database (Denmark)

Klimczak, Pawel; Munk-Nielsen, Stig

2009-01-01

is on performance improvement of this type of the converter. Use of foil windings helps to reduce conduction losses in magnetic components and to reduce size of these components. Also it has been demonstrated that the regulation range of this type of converter can be increased by operation with duty cycle lower......The boost converter with the three-state switching cell seems to be a good candidate for a dc-dc stage for non-isolated generators based on alternative energy sources. It provides a high voltage gain, a reduced voltage stress on transistors and limited input current ripples. In this paper the focus...

Controllable Grid Interface for Testing Ancillary Service Controls and Fault Performance of Utility-Scale Wind Power Generation: Preprint

Energy Technology Data Exchange (ETDEWEB)

Gevorgian, Vahan; Koralewicz, Przemyslaw; Wallen, Robb; Muljadi, Eduard

2017-02-01

The rapid expansion of wind power has led many transmission system operators to demand modern wind power plants to comply with strict interconnection requirements. Such requirements involve various aspects of wind power plant operation, including fault ride-through and power quality performance as well as the provision of ancillary services to enhance grid reliability. During recent years, the National Renewable Energy Laboratory (NREL) of the U.S. Department of Energy has developed a new, groundbreaking testing apparatus and methodology to test and demonstrate many existing and future advanced controls for wind generation (and other renewable generation technologies) on the multimegawatt scale and medium-voltage levels. This paper describes the capabilities and control features of NREL's 7-MVA power electronic grid simulator (also called a controllable grid interface, or CGI) that enables testing many active and reactive power control features of modern wind turbine generators -- including inertial response, primary and secondary frequency responses, and voltage regulation -- under a controlled, medium-voltage grid environment. In particular, this paper focuses on the specifics of testing the balanced and unbalanced fault ride-through characteristics of wind turbine generators under simulated strong and weak medium-voltage grid conditions. In addition, this paper provides insights on the power hardware-in-the-loop feature implemented in the CGI to emulate (in real time) the conditions that might exist in various types of electric power systems under normal operations and/or contingency scenarios. Using actual test examples and simulation results, this paper describes the value of CGI as an ultimate modeling validation tool for all types of 'grid-friendly' controls by wind generation.

Wind energy conversion system

Science.gov (United States)

Longrigg, Paul

1987-01-01

The wind energy conversion system includes a wind machine having a propeller connected to a generator of electric power, the propeller rotating the generator in response to force of an incident wind. The generator converts the power of the wind to electric power for use by an electric load. Circuitry for varying the duty factor of the generator output power is connected between the generator and the load to thereby alter a loading of the generator and the propeller by the electric load. Wind speed is sensed electro-optically to provide data of wind speed upwind of the propeller, to thereby permit tip speed ratio circuitry to operate the power control circuitry and thereby optimize the tip speed ratio by varying the loading of the propeller. Accordingly, the efficiency of the wind energy conversion system is maximized.

Reduced Cost of Reactive Power in Doubly Fed Induction Generator Wind Turbine System with Optimized Grid Filter

DEFF Research Database (Denmark)

Zhou, Dao; Blaabjerg, Frede; Franke, Toke

2014-01-01

The modern grid requirement has caused that the wind power system behaves more like conventional rotating generators and it is able to support certain amount of the reactive power. For a typical doubly-fed induction generator wind turbine system, the reactive power can be supported either through...... for the generator and the wind power converter in terms of the reactive power done by the rotor-side converter or the grid-side converter with various grid filters. Afterwards, the annual energy loss is also estimated based on yearly wind profile. Finally, experimental results of the loss distribution are performed...... the rotor-side converter or the grid-side converter. This paper firstly compares the current ripples and supportive reactive power ranges between the conventional L and optimized LCL filter, if the reactive power is injected from the grid-side converter. Then, the loss distribution is evaluated both...

Reduced Cost of Reactive Power in Doubly Fed Induction Generator Wind Turbine System With Optimized Grid Filter

DEFF Research Database (Denmark)

Zhou, Dao; Blaabjerg, Frede; Franke, Toke

2015-01-01

The modern grid requirement has caused that the wind power system behaves more like conventional rotating generators, and it is able to support certain amount of the reactive power. For a typical doubly fed induction generator (DFIG) wind turbine system, the reactive power can be supported either...... for the generator and the wind power converter in terms of the reactive power done by the rotor-side converter or the grid-side converter with various grid filters. Afterward, the annual energy loss is also estimated based on yearly wind profile. Finally, experimental results of the loss distribution are performed...... through the rotor-side converter or the grid-side converter. This paper first compares the current ripples and supportive reactive power ranges between the conventional L and optimized LCL filter, if the reactive power is injected from the grid-side converter. Then, the loss distribution is evaluated both...

Power quality issues of 3MW direct-driven PMSG wind turbine

OpenAIRE

Ahmed, IA; Zobaa, AF; Taylor, GA

2015-01-01

This paper presents power quality issues of a grid connected wind generation system with a MW-class direct-driven permanent magnet synchronous generator (PMSG). A variable speed wind turbine model was simulated and developed with the simulation tool of PSCAD/EMTDC. The model includes a wind turbine with one mass-model drive train model, a PMSG model and a full-scale voltage source back to back PWM converter. The converter controller model is employed in the dq-synchronous rotating reference f...

A control strategy for multi-functional converter to improve grid power quality

DEFF Research Database (Denmark)

Li, Fei; Wang, Xiongfei; Chen, Zhe

2011-01-01

The extensive use of converter-interfacing distributed energy resources (DER), combined with a large amount of nonlinear and unbalanced loads connected to the distribution power system, has led to power quality problem. This paper proposes a control strategy for a three-phase four-leg multi-funct......) for multi-functional converter is described. Simulation and hardware in the loop real time test results carried on a three-phase four-wire distributed generation system illustrate the effectiveness of the proposed control strategy.......The extensive use of converter-interfacing distributed energy resources (DER), combined with a large amount of nonlinear and unbalanced loads connected to the distribution power system, has led to power quality problem. This paper proposes a control strategy for a three-phase four-leg multi......-functional converter which can compensate reactive power, harmonic currents, unbalance, and neutral current simultaneously under distorted voltage conditions, besides the active power exchange. The capacity of the converter is taken into account. The proposed control strategy based on synchronous reference frame (SRF...

Analysis of the Drivetrain Performance of a Large Horizontal-Axis Wind Turbine: An Aeroelastic Approach

DEFF Research Database (Denmark)

Gebhardt, Cristian; Preidikman, Sergio; Massa, Julio C

2010-01-01

by means of the rotor blades, and then converting the rotational energy of the rotor blades into electrical energy by using a generator. The amount of available energy which the wind transfers to the rotor depends on the mass density of the air, the sweep area of the rotor blades, and the wind speed...... to generate electricity from the kinetic energy of the wind. In order to capture this energy and convert it to electrical energy, one needs to have a device that is capable of extracting the energy available in the wind stream. This device, or turbine, is usually composed of three major parts: the ‘rotor...... blades’, the drivetrain and the generator. The blades are the part of the turbine that touches energy in the wind and rotates about an axis. Extracting energy from the wind is typically accomplished by first mechanically converting the velocity of the wind into a rotational motion of the wind turbine...

Dynamic Models for Wind Turbines and Wind Power Plants

Energy Technology Data Exchange (ETDEWEB)

Singh, M.; Santoso, S.

2011-10-01

The primary objective of this report was to develop universal manufacturer-independent wind turbine and wind power plant models that can be shared, used, and improved without any restrictions by project developers, manufacturers, and engineers. Manufacturer-specific models of wind turbines are favored for use in wind power interconnection studies. While they are detailed and accurate, their usages are limited to the terms of the non-disclosure agreement, thus stifling model sharing. The primary objective of the work proposed is to develop universal manufacturer-independent wind power plant models that can be shared, used, and improved without any restrictions by project developers, manufacturers, and engineers. Each of these models includes representations of general turbine aerodynamics, the mechanical drive-train, and the electrical characteristics of the generator and converter, as well as the control systems typically used. To determine how realistic model performance is, the performance of one of the models (doubly-fed induction generator model) has been validated using real-world wind power plant data. This work also documents selected applications of these models.

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.

Wind power potential and integration in Africa

Directory of Open Access Journals (Sweden)

Agbetuyi, A.F.

2013-03-01

Full Text Available Wind energy penetration into power networks is increasing very rapidly all over the world. The great concern about global warming and continued apprehensions about nuclear power around the world should drive most countries in Africa into strong demand for wind generation because of its advantages which include the absence of harmful emissions, very clean and almost infinite availability of wind that is converted into electricity. This paper shows the power available in the wind. It also gives an overview of the wind power potential and integration in some selected Africa countries like Egypt, Morocco, South Africa and Nigeria and the challenges of wind power integration in Africa’s continent are also discussed. The Northern part of Africa is known to be Africa’s Wind pioneers having installed and connected the Wind Energy Converters (WEC to the grid. About 97% of the continent’s total wind installations are located in Egypt, Morocco and Tunisia. Research work should commence on the identified sites with high wind speeds in those selected Africa countries, so that those potential sites can be connected to the grid. This is because the ability of a site to sufficiently accommodate wind generation not only depends on wind speeds but on its ability to interconnect to the existing grid. If these wind energy potentials are tapped and connected to the grid, the erratic and epileptic power supply facing most countries in Africa will be reduced; thereby reducing rural-urban migration and more jobs will be created.

Transient analysis of variable-speed wind turbines at wind speed disturbances and a pitch control malfunction

International Nuclear Information System (INIS)

Melicio, R.; Mendes, V.M.F.; Catalao, J.P.S.

2011-01-01

As wind power generation undergoes rapid growth, new technical challenges emerge: dynamic stability and power quality. The influence of wind speed disturbances and a pitch control malfunction on the quality of the energy injected into the electric grid is studied for variable-speed wind turbines with different power-electronic converter topologies. Additionally, a new control strategy is proposed for the variable-speed operation of wind turbines with permanent magnet synchronous generators. The performance of disturbance attenuation and system robustness is ascertained. Simulation results are presented and conclusions are duly drawn.

Transient analysis of variable-speed wind turbines at wind speed disturbances and a pitch control malfunction

Energy Technology Data Exchange (ETDEWEB)

Melicio, R. [Department of Electromechanical Engineering, University of Beira Interior, R. Fonte do Lameiro, 6201-001 Covilha (Portugal); Mendes, V.M.F. [Department of Electrical Engineering and Automation, Instituto Superior de Engenharia de Lisboa, R. Conselheiro Emidio Navarro, 1950-062 Lisbon (Portugal); Catalao, J.P.S. [Department of Electromechanical Engineering, University of Beira Interior, R. Fonte do Lameiro, 6201-001 Covilha (Portugal); Center for Innovation in Electrical and Energy Engineering, Instituto Superior Tecnico, Technical University of Lisbon, Av. Rovisco Pais, 1049-001 Lisbon (Portugal)

2011-04-15

As wind power generation undergoes rapid growth, new technical challenges emerge: dynamic stability and power quality. The influence of wind speed disturbances and a pitch control malfunction on the quality of the energy injected into the electric grid is studied for variable-speed wind turbines with different power-electronic converter topologies. Additionally, a new control strategy is proposed for the variable-speed operation of wind turbines with permanent magnet synchronous generators. The performance of disturbance attenuation and system robustness is ascertained. Simulation results are presented and conclusions are duly drawn. (author)

Wind energy in the built environment : Concentrator effects of buildings

NARCIS (Netherlands)

Mertens, S.

2006-01-01

This thesis deals with wind energy conversion in the built environment. It gives a description of the wind resources in the built environment that can be converted into energy by a wind turbine. With a focus on maximum energy yield of the wind turbine, it especially deals with the integration of

Development of a Wind Directly Forced Heat Pump and Its Efficiency Analysis

OpenAIRE

Jwo, Ching-Song; Chien, Zi-Jie; Chen, Yen-Lin; Chien, Chao-Chun

2013-01-01

The requirements of providing electric energy through the wind-forced generator to the heat pump for water cooling and hot water heating grow significantly by now. This study proposes a new technique to directly adopt the wind force to drive heat pump systems, which can effectively reduce the energy conversion losses during the processes of wind force energy converting to electric energy and electric energy converting to kinetic energy. The operation of heat pump system transfers between chil...

Voltage Quality of Grid Connected Wind Turbines

DEFF Research Database (Denmark)

Chen, Zhe; Blaabjerg, Frede; Sun, Tao

2004-01-01

Grid connected wind turbines may cause quality problems, such as voltage variation and flicker. This paper discusses the voltage variation and flicker emission of grid connected wind turbines with doubly-fed induction generators. A method to compensate flicker by using a voltage source converter...

A Review on Direct Power Control for Applications to Grid Connected PWM Converters

Directory of Open Access Journals (Sweden)

T. A. Trivedi

2015-08-01

Full Text Available The Direct Power Control strategy has become popular as an alternative to the conventional vector oriented control strategy for grid connected PWM converters. In this paper, Direct Power Control as applied to various applications of grid connected converters is reviewed. The Direct Power Control for PWM rectifiers, Grid Connected DC/AC inverters applications such as renewable energy sources interface, Active Power Filters, Doubly Fed Induction Generators and AC-DC-AC converters are discussed. Control strategies such as Look-Up table based control, predictive control, Virtual Flux DPC, Model based DPC and DPC-Space Vector Modulation are critically reviewed. The effects of various key parameters such as selection of switching vector, sampling time, hysteresis band and grid interfacing on performance of direct power controlled converters are presented.

Saturation wind power potential and its implications for wind energy.

Science.gov (United States)

Jacobson, Mark Z; Archer, Cristina L

2012-09-25

Wind turbines convert kinetic to electrical energy, which returns to the atmosphere as heat to regenerate some potential and kinetic energy. As the number of wind turbines increases over large geographic regions, power extraction first increases linearly, but then converges to a saturation potential not identified previously from physical principles or turbine properties. These saturation potentials are >250 terawatts (TW) at 100 m globally, approximately 80 TW at 100 m over land plus coastal ocean outside Antarctica, and approximately 380 TW at 10 km in the jet streams. Thus, there is no fundamental barrier to obtaining half (approximately 5.75 TW) or several times the world's all-purpose power from wind in a 2030 clean-energy economy.

Concept Study of Foundation Systems for Wave Energy Converters

DEFF Research Database (Denmark)

Molina, Salvador Devant; Vaitkunaite, Evelina; Ibsen, Lars Bo

Analysis of possible foundation solution for Wave Energy Converters (WEC) is presented by investigating and optimizing novel foundation systems recently developed for offshore wind turbines. Gravity based, pile and bucket foundations are innovative foundation systems that are analyzed. Concept...

Single stage grid converters for battery energy storage

DEFF Research Database (Denmark)

Trintis, Ionut; Munk-Nielsen, Stig; Teodorescu, Remus

2010-01-01

Integration of renewable energy systems in the power system network such as wind and solar is still a challenge in our days. Energy storage systems (ESS) can overcome the disadvantage of volatile generation of the renewable energy sources. This paper presents power converters for battery energy...

Wind Resource Assessment of Gujarat (India)

Energy Technology Data Exchange (ETDEWEB)

Draxl, C.; Purkayastha, A.; Parker, Z.

2014-07-01

India is one of the largest wind energy markets in the world. In 1986 Gujarat was the first Indian state to install a wind power project. In February 2013, the installed wind capacity in Gujarat was 3,093 MW. Due to the uncertainty around existing wind energy assessments in India, this analysis uses the Weather Research and Forecasting (WRF) model to simulate the wind at current hub heights for one year to provide more precise estimates of wind resources in Gujarat. The WRF model allows for accurate simulations of winds near the surface and at heights important for wind energy purposes. While previous resource assessments published wind power density, we focus on average wind speeds, which can be converted to wind power densities by the user with methods of their choice. The wind resource estimates in this study show regions with average annual wind speeds of more than 8 m/s.

Short circuit signatures from different wind turbine generator types

DEFF Research Database (Denmark)

Martinez, Jorge; Kjær, Philip C.; Rodriguez, Pedro

2011-01-01

Modern wind power plants are required and designed to ride through faults in the network, subjected to the fault clearance and following grid code demands. Beside voltage support during faults, the wind turbine fault current contribution is important to establish the correct settings for the relay...... of the protections. The following wind turbine generator during faults have been studied: (i) induction generator, (ii) induction generator with variable rotor resistance (iii) converter-fed rotor (often referred to as DFIG) and (iv) full scale converter. To make a clear comparison and performance analysis during...... faults, and the consequent effects on substation protections, the aforementioned configurations have been simulated using PSCAD/EMTDC, with the same power plant configuration, electrical grid and generator data. Additionally, a comparison of these wind turbine technologies with a conventional power plant...

A bidirectional soft switched ultracapacitor interface circuit for hybrid electric vehicles

Energy Technology Data Exchange (ETDEWEB)

Farzanehfard, Hosein; Beyragh, Dawood Shekari; Adib, Ehsan [Electrical and Computer Engineering Department, Isfahan University of Technology, Isfahan 84156 (Iran)

2008-12-15

Ultracapacitors are used as auxiliary elements beside batteries to increase peak power capability and battery life in hybrid electric vehicles. In such a configuration, a bidirectional high efficiency converter is required as an interface between ultracapacitors and batteries. Since the voltage level of ultracapacitors and batteries are different, the interface must be able to increase or decrease the voltage level in each power flow direction while limiting the current. This paper presents a zero voltage transition (ZVT) buck-and-boost converter for ultracapacitors interface. All the switches in the proposed converter are soft switched to reduce switching losses and increase efficiency. The converter operational modes are analyzed and its performance is discussed. Finally, the experimental results from a 150 W laboratory prototype are presented which justify the theoretical analysis. (author)

Electrical Aspects of Wind Turbines

DEFF Research Database (Denmark)

Chen, Zhe; Blaabjerg, Frede

2009-01-01

This is the most authoritative single volume on offshore wind power yet published. Distinguished experts, mainly from Europe's leading universities, have contributed a collection of peer reviewed papers on the interfaces between wind power technology and marine engineering. The range of issues...

Loss of Synchronism of Wind Turbine Converters during Low Voltage Grid Faults

DEFF Research Database (Denmark)

Göksu, Ömer; Sørensen, Poul Ejnar; Iov, Florin

2014-01-01

In the recent grid codes, wind power plants are required to stay connected and inject reactive and active currents during grid short-circuit faults, even when the grid voltage drops down to zero. However, the physical fact, Loss of Synchronism (LOS) of wind turbines during these very low voltage ...... as whole. Additionally, existing methods to solve the LOS problem are briefly reviewed, and a closed loop frequency based solution is implemented within PowerFactory simulations of a detailed generic wind power plant model....

Modeling of asymmetrical boost converters

Directory of Open Access Journals (Sweden)

Eliana Isabel Arango Zuluaga

2014-01-01

Full Text Available The asymmetrical interleaved dual boost (AIDB is a fifth-order DC/DC converter designed to interface photovoltaic (PV panels. The AIDB produces small current harmonics to the PV panels, reducing the power losses caused by the converter operation. Moreover, the AIDB provides a large voltage conversion ratio, which is required to step-up the PV voltage to the large dc-link voltage used in grid-connected inverters. To reject irradiance and load disturbances, the AIDB must be operated in a closed-loop and a dynamic model is required. Given that the AIDB converter operates in Discontinuous Conduction Mode (DCM, classical modeling approaches based on Continuous Conduction Mode (CCM are not valid. Moreover, classical DCM modeling techniques are not suitable for the AIDB converter. Therefore, this paper develops a novel mathematical model for the AIDB converter, which is suitable for control-pur-poses. The proposed model is based on the calculation of a diode current that is typically disregarded. Moreover, because the traditional correction to the second duty cycle reported in literature is not effective, a new equation is designed. The model accuracy is contrasted with circuital simulations in time and frequency domains, obtaining satisfactory results. Finally, the usefulness of the model in control applications is illustrated with an application example.

Reliability Evaluation of Power Capacitors in a Wind Turbine System

DEFF Research Database (Denmark)

Zhou, Dao; Blaabjerg, Frede

2018-01-01

With the increasing penetration of wind power, reliable and cost-effective wind energy production is of more and more importance. The doubly-fed induction generator based partial-scale wind power converter is still dominating in the existing wind farms. In this paper, the reliability assessment...... block diagram is used to bridge the gap between the Weibull distribution based component-level individual capacitor and the capacitor bank. A case study of a 2 MW wind power converter shows that the lifetime is significantly reduced from the individual capacitor to the capacitor bank. Besides, the dc...... of power capacitors is studied considering the annual mission profile. According to an electro-thermal stress evaluation, the time-to-failure distribution of both the dc-link capacitor and ac-side filter capacitor is detailed investigated. Aiming for the systemlevel reliability analysis, a reliability...

Wind turbines fundamentals, technologies, application, economics

CERN Document Server

Hau, Erich

2013-01-01

"Wind Turbines" addresses all those professionally involved in research, development, manufacture and operation of wind turbines. It provides a cross-disciplinary overview of modern wind turbine technology and an orientation in the associated technical, economic and environmental fields.  In its revised third edition, special emphasis has been given to the latest trends in wind turbine technology and design, such as gearless drive train concepts, as well as on new fields of application, in particular the offshore utilisation of wind energy. The author has gained experience over decades designing wind energy converters with a major industrial manufacturer and, more recently, in technical consulting and in the planning of large wind park installations, with special attention to economics.

Co-ordinated voltage control of DFIG wind turbines in uninterrupted operation during grid faults

DEFF Research Database (Denmark)

Hansen, Anca Daniela; Michalke, G.; Sørensen, Poul Ejnar

2007-01-01

Emphasis in this article is on the design of a co-ordinated voltage control strategy for doubly fed induction generator (DFIG) wind turbines that enhances their capability to provide grid support during grid faults. In contrast to its very good performance in normal operation, the DFIG wind turbine...... concept is quite sensitive to grid faults and requires special power converter protection. The fault ride-through and grid support capabilities of the DFIG address therefore primarily the design of DFIG wind turbine control with special focus on power converter protection and voltage control issues....... A voltage control strategy is designed and implemented in this article, based on the idea that both converters of the DFIG (i.e. rotor-side converter and grid-side converter) participate in the grid voltage control in a co-ordinated manner. By default the grid voltage is controlled by the rotor...

A High-Efficiency Wind Energy Harvester for Autonomous Embedded Systems.

Science.gov (United States)

Brunelli, Davide

2016-03-04

Energy harvesting is currently a hot research topic, mainly as a consequence of the increasing attractiveness of computing and sensing solutions based on small, low-power distributed embedded systems. Harvesting may enable systems to operate in a deploy-and-forget mode, particularly when power grid is absent and the use of rechargeable batteries is unattractive due to their limited lifetime and maintenance requirements. This paper focuses on wind flow as an energy source feasible to meet the energy needs of a small autonomous embedded system. In particular the contribution is on the electrical converter and system integration. We characterize the micro-wind turbine, we define a detailed model of its behaviour, and then we focused on a highly efficient circuit to convert wind energy into electrical energy. The optimized design features an overall volume smaller than 64 cm³. The core of the harvester is a high efficiency buck-boost converter which performs an optimal power point tracking. Experimental results show that the wind generator boosts efficiency over a wide range of operating conditions.

A High-Efficiency Wind Energy Harvester for Autonomous Embedded Systems

Science.gov (United States)

Brunelli, Davide

2016-01-01

Energy harvesting is currently a hot research topic, mainly as a consequence of the increasing attractiveness of computing and sensing solutions based on small, low-power distributed embedded systems. Harvesting may enable systems to operate in a deploy-and-forget mode, particularly when power grid is absent and the use of rechargeable batteries is unattractive due to their limited lifetime and maintenance requirements. This paper focuses on wind flow as an energy source feasible to meet the energy needs of a small autonomous embedded system. In particular the contribution is on the electrical converter and system integration. We characterize the micro-wind turbine, we define a detailed model of its behaviour, and then we focused on a highly efficient circuit to convert wind energy into electrical energy. The optimized design features an overall volume smaller than 64 cm3. The core of the harvester is a high efficiency buck-boost converter which performs an optimal power point tracking. Experimental results show that the wind generator boosts efficiency over a wide range of operating conditions. PMID:26959018

A High-Efficiency Wind Energy Harvester for Autonomous Embedded Systems

Directory of Open Access Journals (Sweden)

Davide Brunelli

2016-03-01

Full Text Available Energy harvesting is currently a hot research topic, mainly as a consequence of the increasing attractiveness of computing and sensing solutions based on small, low-power distributed embedded systems. Harvesting may enable systems to operate in a deploy-and-forget mode, particularly when power grid is absent and the use of rechargeable batteries is unattractive due to their limited lifetime and maintenance requirements. This paper focuses on wind flow as an energy source feasible to meet the energy needs of a small autonomous embedded system. In particular the contribution is on the electrical converter and system integration. We characterize the micro-wind turbine, we define a detailed model of its behaviour, and then we focused on a highly efficient circuit to convert wind energy into electrical energy. The optimized design features an overall volume smaller than 64 cm3. The core of the harvester is a high efficiency buck-boost converter which performs an optimal power point tracking. Experimental results show that the wind generator boosts efficiency over a wide range of operating conditions.

Impact of Wind Shear and Tower Shadow Effects on Power System with Large Scale Wind Power Penetration

DEFF Research Database (Denmark)

Hu, Weihao; Su, Chi; Chen, Zhe

2011-01-01

presents a simulation model of a variable speed wind farm with permanent magnet synchronous generators (PMSGs) and fullscale back-to-back converters in the simulation tool of DIgSILENT/PowerFactory. In this paper, the impacts of wind shear and tower shadow effects on the small signal stability of power......Grid connected wind turbines are fluctuating power sources due to wind speed variations, the wind shear and the tower shadow effects. The fluctuating power may be able to excite the power system oscillation at a frequency close to the natural oscillation frequency of a power system. This paper...... systems with large scale wind power penetrations are investigated during continuous operation based on the wind turbine model and the power system model....

Power Oscillation Damping from VSC-HVDC Connected Offshore Wind Power Plants

DEFF Research Database (Denmark)

Zeni, Lorenzo; Eriksson, Robert; Goumalatsos, Spyridon

2016-01-01

The implementation of power oscillation damping service on offshore wind power plants connected to onshore grids by voltage-source-converter-based high voltage direct current transmission is discussed. Novel design guidelines for damping controllers on voltage-source converters and wind power plant...... regarding real wind power plants are discussed: 1) robustness against control/communication delays; 2) limitations due to mechanical resonances in wind turbine generators; 3) actual capability of wind power plants to provide damping without curtailing production; and 4) power-ramp rate limiters....... controllers are derived, using phasor diagrams and a test network model and are then verified on a generic power system model. The effect of voltage regulators is analyzed, which is important for selecting the most robust damping strategy. Furthermore, other often disregarded practical implementation aspects...

Optimization Control of Bidirectional Cascaded DC-AC Converter Systems

DEFF Research Database (Denmark)

Tian, Yanjun

in bidirectional cascaded converter. This research work analyses the control strategies based on the topology of dual active bridges converter cascaded with a three phase inverter. It firstly proposed a dc link voltage and active power coordinative control method for this cascaded topology, and it can reduce dc....... The connections of the renewable energy sources to the power system are mostly through the power electronic converters. Moreover, for high controllability and flexibility, power electronic devices are gradually acting as the interface between different networks in power systems, promoting conventional power...... the bidirectional power flow in the distribution level of power systems. Therefore direct contact of converters introduces significant uncertainties to power system, especially for the stability and reliability. This dissertation studies the optimization control of the two stages directly connected converters...

Cooperative control of VSC-HVDC connected offshore wind farm with Low-Voltage Ride-Through capability

DEFF Research Database (Denmark)

Liu, Yan; Wang, Xiongfei; Chen, Zhe

2012-01-01

The Low-Voltage Ride-Through (LVRT) has become an important grid requirement for offshore wind farms connecting with Voltage Source Converter based High Voltage Direct Current (VSC-HVDC) links. In this paper, a cooperative control strategy with LVRT ability is proposed for a VSC-HVDC connected...... variable speed Squirrel-Cage Induction Generator (SCIG) wind farm. The approach employs a DC-link voltage versus offshore AC-bus frequency droop control on the offshore converter of VSC-HVDC link. Thus, the back-to-back converters of SCIG wind turbines can adjust the generated active power based on the AC......-bus frequency deviations, so that a fast power reduction on the wind farm side can be achieved. The EMTDC/PSCAD simulations are performed on a 300 MW offshore variable speed SCIG wind farm. Simulation results confirm the effectiveness of the proposed control method....

A High-Efficient Low-Cost Converter for Capacitive Wireless Power Transfer Systems

Directory of Open Access Journals (Sweden)

Il-Oun Lee

2017-09-01

Full Text Available Growth of the Internet of Things (IoT spurs need for new ways of delivering power. Wireless power transfer (WPT has come into the spotlight from both academia and industry as a promising way to power the IoT devices. As one of the well-known WPT techniques, the capacitive power transfer (CPT has the merit of low electromagnetic radiation and amenability of combined power and data transfer over a capacitive interface. However, applying the CPT to the IoT devices is still challenging in reality. One of the major issues is due to the small capacitance of the capacitive interface, which results in low efficiency of the power transfer. To tackle this problem, we present a new step-up single-switch quasi-resonant (SSQR converter for the CPT system. To enhance the CPT efficiency, the proposed converter is designed to operate at low frequency and drive small current into the capacitive interfaces. In addition, by eliminating resistor-capacitor-diode (RCD snubber in the converter, we reduce the implementation cost of the CPT system. Based on intensive experimental work with a CPT system prototype that supports maximum 50 W (100 V/0.5 A power transfer, we demonstrate the functional correctness of the converter that achieves up to 93% efficiency.

Control Strategies for Smoothing of Output Power of Wind Energy Conversion Systems

Science.gov (United States)

Pratap, Alok; Urasaki, Naomitsu; Senju, Tomonobu

2013-10-01

This article presents a control method for output power smoothing of a wind energy conversion system (WECS) with a permanent magnet synchronous generator (PMSG) using the inertia of wind turbine and the pitch control. The WECS used in this article adopts an AC-DC-AC converter system. The generator-side converter controls the torque of the PMSG, while the grid-side inverter controls the DC-link and grid voltages. For the generator-side converter, the torque command is determined by using the fuzzy logic. The inputs of the fuzzy logic are the operating point of the rotational speed of the PMSG and the difference between the wind turbine torque and the generator torque. By means of the proposed method, the generator torque is smoothed, and the kinetic energy stored by the inertia of the wind turbine can be utilized to smooth the output power fluctuations of the PMSG. In addition, the wind turbines shaft stress is mitigated compared to a conventional maximum power point tracking control. Effectiveness of the proposed method is verified by the numerical simulations.

Desain Kontrol Multi – Input DC–DC Converter Sistem Hibrid Turbin Angin dan Sel Surya Menggunakan Kontrol Fuzzy Logic untuk Tegangan Rendah

Directory of Open Access Journals (Sweden)

Feby Agung Pamuji

2015-09-01

Full Text Available this paper describes a hybrid system that consist of Wind Turbines and Photovoltaic to supply electricity continuously for load. Output of Wind Turbines and Photovoltaic is controlled in order to generate maximum power. Multiple-input dc-dc converters is used to control power flow in order to have MPP (Maximum Power Point. Converter control using Fuzzy logic controller to control the output in order to be obtained MPP (Maximum Power Point from Wind Turbines and Photovoltaic, so the efficiency of wind turbines and photovoltaic can be improved.

SIG Galileo final converter technical summary report

International Nuclear Information System (INIS)

Hinderman, J.D.

1979-05-01

The report is primarily concerned with the work performed for DOE on converter development and fabrication for the NASA Galileo Jupiter mission as a DOE prime contractor with interface primarily with Teledyne Energy Systems. The activities reported on were directed toward design, analysis and testing of modules and converters SN-1 thru SN-7 and attendant Quality Control and Reliability effort. Although assembly and testing of SN-1 was not accomplished due to the stop work order, the design was virtually completed and a significant amount of subcontracting and manufacturing of both module and converter components was underway. These subcontracting and manufacturing activities were selectively closed down depending upon degree of completion and material or hardware potential usage in the Technology Program

Ripple Mitigation with Improved Line-Load Transients Response in Two-Stage DC-DC-AC Converter

DEFF Research Database (Denmark)

Gautam, Aditya R.; Gaurav, Kumar; Guerrero, Josep M.

2018-01-01

. The front-end boost converter in the considered two-stage converter interfaces a battery bank and single phase inverter fed loads. The control shapes the output impedance of boost converter to reduce the ripple component at battery input. Secondly, the proposed controller achieves good dynamic performance...

PV source based high voltage gain current fed converter

Science.gov (United States)

Saha, Soumya; Poddar, Sahityika; Chimonyo, Kudzai B.; Arunkumar, G.; Elangovan, D.

2017-11-01

This work involves designing and simulation of a PV source based high voltage gain, current fed converter. It deals with an isolated DC-DC converter which utilizes boost converter topology. The proposed converter is capable of high voltage gain and above all have very high efficiency levels as proved by the simulation results. The project intends to produce an output of 800 V dc from a 48 V dc input. The simulation results obtained from PSIM application interface were used to analyze the performance of the proposed converter. Transformer used in the circuit steps up the voltage as well as to provide electrical isolation between the low voltage and high voltage side. Since the converter involves high switching frequency of 100 kHz, ultrafast recovery diodes are employed in the circuitry. The major application of the project is for future modeling of solar powered electric hybrid cars.

Smart — STATCOM control strategy implementation in wind power plants

DEFF Research Database (Denmark)

Sintamarean, Nicolae Christian; Cantarellas, Antoni Mir; Miranda, H.

2012-01-01

High penetration of wind energy into the grid may introduce stability and power quality problems due to the fluctuating nature of the wind and the increasing complexity of the power system. By implementing advanced functionalities in power converters, it is possible to improve the performance...... of the wind farm and also to provide grid support, as it is required by the grid codes. One of the main compliance difficulties that can be found in such power plants are related to reactive power compensation and to keep the harmonics content between the allowed limits, even if the power of the WPP...... converters is increasing. This paper deals with an advanced control strategy design of a three-level converter performing STATCOM and Active Filter functionalities. The proposed system is called Smart-STATCOM since it has the capability of self-controlling reactive power and harmonic voltages at the same...

New Multiphase Hybrid Boost Converter with Wide Conversion Ratio for PV System

Directory of Open Access Journals (Sweden)

Ioana-Monica Pop-Calimanu

2014-01-01

Full Text Available A new multiphase hybrid boost converter, with wide conversion ratio as a solution for photovoltaic energy system, is presented in this paper. To ensure that all the phases of the converter operate at the same switching frequency we use interleaving topology. The proposed converter can be used as an interface between the PV system and the DC load/inverter. This multiphase converter has the advantage of reduced value and physical size of the input and output capacitor as well as the effort for the inductors. To validate the operation of the converter we provide the analyses and the simulation results of the converter.

Wind power plants the fuel savers

International Nuclear Information System (INIS)

Akbar, M.

2006-01-01

Wind is a converted from of solar energy. The Sun's radiation heats different parts of the earth at variable rates as the earth surfaces absorb or reflect at different rates. This in turn causes portions of the atmosphere to warm at varying levels. The hot air rises reducing atmospheric pressure at the earth's surface beneath, the cooler air rushes to replace it and in the process creates a momentum called wind. Air possesses mass and when it sets into motion, it contains the energy of that motion, called the Kinetic Energy. A part of the Kinetic Energy of the wind can be converted into other forms of energy i.e. mechanical force or electric power that can be used to perform work. The cost of electric energy from the wind system has dropped from the initial cost of 30 to 40 Cents per kWh to about 5 to 7 Cents/k Wh during the past 20 years. The costs are continually declining as the technology is advanced, the unit size is increased and larger plants are built. Wind power is now a viable, robust and fast growing industry. The cost of wind energy is expected to drop to 2 to 3 Cents / kWh during the next 5 to 10 years. Due to sky-rocketing prices of the fossil fuels, the competitive position of power generation technologies is rapidly changing. Wind energy is likely to emerge as the cheapest source of electric power generation in the global market in the near future. The current assessment of the global wind resources indicate that the wind energy potential is more than double the world's electricity needs. (author)

Modeling and control of PMSG-based variable-speed wind turbine

Energy Technology Data Exchange (ETDEWEB)

Kim, Hong-Woo; Ko, Hee-Sang [Wind Energy Research Center, Korea Institute of Energy Research, Yuseong-gu Jang-Dong 71-2,305-343 Daejeon (Korea); Kim, Sung-Soo [Chungbuk National University (Korea)

2010-01-15

This paper presents a control scheme of a variable-speed wind turbine with a permanent-magnetic synchronous generator (PMSG) and full-scale back-to-back voltage source converter. A comprehensive dynamical model of the PMSG wind turbine and its control scheme is presented. The control scheme comprises both the wind-turbine control itself and the power-converter control. In addition, since the PMSG wind turbine is able to support actively the grid due to its capability to control independently active and reactive power production to the imposed set-values with taking into account its operating state and limits, this paper presents the supervisory reactive power control scheme in order to regulate/contribute the voltage at a remote location. The ability of the control scheme is assessed and discussed by means of simulations, based on a candidate site of the offshore wind farm in Jeju, Korea. (author)

UDE-based control of variable-speed wind turbine systems

Science.gov (United States)

Ren, Beibei; Wang, Yeqin; Zhong, Qing-Chang

2017-01-01

In this paper, the control of a PMSG (permanent magnet synchronous generator)-based variable-speed wind turbine system with a back-to-back converter is considered. The uncertainty and disturbance estimator (UDE)-based control approach is applied to the regulation of the DC-link voltage and the control of the RSC (rotor-side converter) and the GSC (grid-side converter). For the rotor-side controller, the UDE-based vector control is developed for the RSC with PMSG control to facilitate the application of the MPPT (maximum power point tracking) algorithm for the maximum wind energy capture. For the grid-side controller, the UDE-based vector control is developed to control the GSC with the power reference generated by a UDE-based DC-link voltage controller. Compared with the conventional vector control, the UDE-based vector control can achieve reliable current decoupling control with fast response. Moreover, the UDE-based DC-link voltage regulation can achieve stable DC-link voltage under model uncertainties and external disturbances, e.g. wind speed variations. The effectiveness of the proposed UDE-based control approach is demonstrated through extensive simulation studies in the presence of coupled dynamics, model uncertainties and external disturbances under varying wind speeds. The UDE-based control is able to generate more energy, e.g. by 5% for the wind profile tested.

Control of Permanent Magnet Synchronous Generator for large wind turbines

DEFF Research Database (Denmark)

Busca, Cristian; Stan, Ana-Irina; Stanciu, Tiberiu

2010-01-01

Direct Torque Control (DTC) and Field Oriented Control (FOC) are the most dominant control strategies used in generators for wind turbines. In this paper both control methods were implemented on a Permanent Magnet Synchronous Generator (PMSG). The variable speed wind turbine with full scale power...... converter topology was chosen for design. Parameters from a 2 MW wind turbine were used for system modeling. All the components of the wind turbine system (WTS), except the DC-link and the grid site converter were implemented in MATLAB/Simulink. The pitch controller was used to limit the output power...... produced by the turbine. DTC and FOC strategies, using SVM were used to control the generator rotor speed. The performance of the two control strategies were compared after different tests have been carried out....

Application of Simplified Neutral Point Clamped Multilevel Converter in a Small Wind Turbine

Directory of Open Access Journals (Sweden)

Mlodzikowski Pawel

2014-05-01

Full Text Available In low power distributed generation systems low cost together with the energy quality requirements are a key element. It is known that quality of voltage waveforms generated from multilevel converters is better in comparison with those from two-level. Due to advancements in power electronics and microcontrollers, multilevel converters are being built with the use of integrated power modules thus this type of converters are getting more compact in size. This paper investigates performance of a derivation from the most popular multilevel topology - a neutral point clamped converter (NPC. Applying the idea for simplifying the topology by reducing the number of switches (what came from drives this NPC converter is capable of bidirectional AC/DC/AC operation. For the AC/DC part two schemes are tested: Direct Torque Control Space Vector Modulated and Field Oriented Control but for the DC/AC part a control scheme utilizing the proportional-resonant controller was chosen. Laboratory setup was based on a permanent magnet synchronous generator with control and acquisition completed with the help of dSpace 1005 control box. Experimental verification shows that system operates properly.

DC-DC power converter research for Orbiter/Station power exchange

Science.gov (United States)

Ehsani, M.

1993-01-01

This project was to produce innovative DC-DC power converter concepts which are appropriate for the power exchange between the Orbiter and the Space Station Freedom (SSF). The new converters must interface three regulated power buses on SSF, which are at different voltages, with three fuel cell power buses on the Orbiter which can be at different voltages and should be tracked independently. Power exchange is to be bi-directional between the SSF and the Orbiter. The new converters must satisfy the above operational requirements with better weight, volume, efficiency, and reliability than is available from the present conventional technology. Two families of zero current DC-DC converters were developed and successfully adapted to this application. Most of the converters developed are new and are presented.

On the Predictability of Hub Height Winds

DEFF Research Database (Denmark)

Draxl, Caroline

Wind energy is a major source of power in over 70 countries across the world, and the worldwide share of wind energy in electricity consumption is growing. The introduction of signicant amounts of wind energy into power systems makes accurate wind forecasting a crucial element of modern electrical...... grids. These systems require forecasts with temporal scales of tens of minutes to a few days in advance at wind farm locations. Traditionally these forecasts predict the wind at turbine hub heights; this information is then converted by transmission system operators and energy companies into predictions...... of power output at wind farms. Since the power available in the wind is proportional to the wind speed cubed, even small wind forecast errors result in large power prediction errors. Accurate wind forecasts are worth billions of dollars annually; forecast improvements will result in reduced costs...

Novel Modified Elman Neural Network Control for PMSG System Based on Wind Turbine Emulator

OpenAIRE

Lin, Chih-Hong

2013-01-01

The novel modified Elman neural network (NN) controlled permanent magnet synchronous generator (PMSG) system, which is directly driven by a permanent magnet synchronous motor (PMSM) based on wind turbine emulator, is proposed to control output of rectifier (AC/DC power converter) and inverter (DC/AC power converter) in this study. First, a closed loop PMSM drive control based on wind turbine emulator is designed to generate power for the PMSG system according to different wind speeds. Then, t...

Control of VSC-HVDC in offshore AC islands with wind power plants: Comparison of two alternatives

DEFF Research Database (Denmark)

Zeni, Lorenzo; Hesselbæk, Bo; Sørensen, Poul Ejnar

2015-01-01

The subject of this paper is the control of offshore AC collection and export networks behind a voltage source converter based high voltage direct current transmission system. The inertia-less nature of such grids makes the control of voltages and power flows potentially more flexible......, but at the same time more prone to instabilities. Focus in this paper is on a voltage source converter based high voltage direct current connected wind power plant. Two state-of-art controllers for the offshore high voltage direct current converter station are compared, both at no-load and when wind turbine...... converters are producing power and controlled with usual vector current control. Sensitivity analyses help identify critical factors influencing stability. The influence of lumping the wind power plant into one converter is assessed by comparison with the full model. The conclusions identify the preferred...

Voltage regulation and power losses reduction in a wind farm integrated MV distribution network

Science.gov (United States)

Fandi, Ghaeth; Igbinovia, Famous Omar; Tlusty, Josef; Mahmoud, Rateb

2018-01-01

A medium-voltage (MV) wind production system is proposed in this paper. The system applies a medium-voltage permanent magnet synchronous generator (PMSG) as well as MV interconnection and distribution networks. The simulation scheme of an existing commercial electric-power system (Case A) and a proposed wind farm with a gearless PMSG insulated gate bipolar transistor (IGBT) power electronics converter scheme (Case B) is compared. The analyses carried out in MATLAB/Simulink environment shows an enhanced voltage profile and reduced power losses, thus, efficiency in installed IGBT power electronics devices in the wind farm. The resulting wind energy transformation scheme is a simple and controllable medium voltage application since it is not restrained by the IGBT power electronics voltage source converter (VSC) arrangement. Active and reactive power control is made possible with the aid of the gearless PMSG IGBT power converters.

A Steady-State Analysis Method for Modular Multilevel Converters Connected to Permanent Magnet Synchronous Generator-Based Wind Energy Conversion Systems

Directory of Open Access Journals (Sweden)

Zhijie Liu

2018-02-01

Full Text Available Modular multilevel converters (MMCs have shown great potential in the area of multi-megawatt wind energy conversion system (WECS based on permanent magnet synchronous generators (PMSGs. However, the studies in this area are few, and most of them refer to the MMC used in high-voltage direct current (HVDC systems, and hence the characteristics of the PMSG are not considered. This paper proposes a steady-state analysis method for MMCs connected to a PMSG-based WECS. In the proposed method, only the wind speed (operating condition is required as input, and all the electrical quantities in the MMC, including the amplitudes, phase angles and their harmonics, can be calculated step by step. The analysis method is built on the proposed d-q frame mathematical model. Interactions of electrical quantities between the MMC and PMSG are comprehensively considered. Moreover, a new way to calculate the average switching functions are adopted in order to improve the accuracy of the analysis method. Applications of the proposed method are also presented, which includes the characteristic analysis of capacitor voltage ripples and the capacitor sizing. Finally, the accuracy of the method and the correctness of the analysis are verified by simulations and experiments.

High temperature co-axial winding transformers

Science.gov (United States)

Divan, Deepakraj M.; Novotny, Donald W.

1993-01-01

The analysis and design of co-axial winding transformers is presented. The design equations are derived and the different design approaches are discussed. One of the most important features of co-axial winding transformers is the fact that the leakage inductance is well controlled and can be made low. This is not the case in conventional winding transformers. In addition, the power density of co-axial winding transformers is higher than conventional ones. Hence, using co-axial winding transformers in a certain converter topology improves the power density of the converter. The design methodology used in meeting the proposed specifications of the co-axial winding transformer specifications are presented and discussed. The final transformer design was constructed in the lab. Co-axial winding transformers proved to be a good choice for high power density and high frequency applications. They have a more predictable performance compared with conventional transformers. In addition, the leakage inductance of the transformer can be controlled easily to suit a specific application. For space applications, one major concern is the extraction of heat from power apparatus to prevent excessive heating and hence damaging of these units. Because of the vacuum environment, the only way to extract heat is by using a cold plate. One advantage of co-axial winding transformers is that the surface area available to extract heat from is very large compared to conventional transformers. This stems from the unique structure of the co-axial transformer where the whole core surface area is exposed and can be utilized for cooling effectively. This is a crucial issue here since most of the losses are core losses.

Energy optimization for a wind DFIG with flywheel energy storage

Energy Technology Data Exchange (ETDEWEB)

Hamzaoui, Ihssen, E-mail: hamzaoui-ihssen2000@yahoo.fr [Laboratory of Instrumentation, Faculty of Electronics and Computer, University of Sciences and Technology Houari Boumediene, BP 32 El-Alia 16111 Bab-Ezzouar (Algeria); Laboratory of Instrumentation, Faculty of Electronics and Computer, University of Khemis Miliana, Ain Defla (Algeria); Bouchafaa, Farid, E-mail: fbouchafa@gmail.com [Laboratory of Instrumentation, Faculty of Electronics and Computer, University of Sciences and Technology Houari Boumediene, BP 32 El-Alia 16111 Bab-Ezzouar (Algeria)

2016-07-25

The type of distributed generation unit that is the subject of this paper relates to renewable energy sources, especially wind power. The wind generator used is based on a double fed induction Generator (DFIG). The stator of the DFIG is connected directly to the network and the rotor is connected to the network through the power converter with three levels. The objective of this work is to study the association a Flywheel Energy Storage System (FESS) in wind generator. This system is used to improve the quality of electricity provided by wind generator. It is composed of a flywheel; an induction machine (IM) and a power electronic converter. A maximum power tracking technique « Maximum Power Point Tracking » (MPPT) and a strategy for controlling the pitch angle is presented. The model of the complete system is developed in Matlab/Simulink environment / to analyze the results from simulation the integration of wind chain to networks.

Improved Adaptive Droop Control Design for Optimal Power Sharing in VSC-MTDC Integrating Wind Farms

Directory of Open Access Journals (Sweden)

Xiaohong Ran

2015-07-01

Full Text Available With the advance of insulated gate bipolar transistor (IGBT converters, Multi-Terminal DC (MTDC based on the voltage-source converter (VSC has developed rapidly in renewable and electric power systems. To reduce the copper loss of large capacity and long distance DC transmission line, an improved droop control design based on optimal power sharing in VSC-MTDC integrating offshore wind farm is proposed. The proposed approach provided a calculation method for power-voltage droop coefficients under two different scenarios either considering local load or not. The available headroom of each converter station was considered as a converter outage, to participate in the power adjustment according to their ability. A four-terminal MTDC model system including two large scale wind farms was set up in PSCAD/EMTDC. Then, the proposed control strategy was verified through simulation under the various conditions, including wind speed variation, rectifier outage and inverter outage, and a three-phase short-circuit of the converter.

Mission-profile based multi-objective optimization of power electronics converter for wind turbines

DEFF Research Database (Denmark)

Gohil, Ghanshyamsinh; Teodorescu, Remus; Kerekes, Tamas

2017-01-01

-objective optimization approach for designing power converter is presented. The objective is to minimize the energy loss for a given load profile as against the conventional approach of minimizing power loss at specific loading conditions. The proposed approach is illustrated by designing a grid-side power converter...

Stability Augmentation of Wind Farm using Variable Speed Permanent Magnet Synchronous Generator

Science.gov (United States)

Rosyadi, Marwan; Muyeen, S. M.; Takahashi, Rion; Tamura, Junji

This paper presents a new control strategy of variable speed permanent magnet wind generator for stability augmentation of wind farm including fixed speed wind turbine with Induction Generator (IG). A new control scheme is developed for two levels back-to-back converters of Permanent Magnet Synchronous Generator (PMSG), by which both active and reactive powers delivered to the grid can be controlled easily. To avoid the converter damage, the DC link protection controller is also proposed in order to protect the dc link circuit during fault condition. To evaluate the control capability of the proposed controllers, simulations are performed on two model systems composed of wind farms connected to an infinite bus. From transient and steady state analyses by using PSCAD/EMTDC, it is concluded that the proposed control scheme is very effective to improve the stability of wind farm for severe network disturbance and randomly fluctuating wind speed.

Discharging a DC bus capacitor of an electrical converter system

Science.gov (United States)

Kajouke, Lateef A; Perisic, Milun; Ransom, Ray M

2014-10-14

A system and method of discharging a bus capacitor of a bidirectional matrix converter of a vehicle are presented here. The method begins by electrically shorting the AC interface of the converter after an AC energy source is disconnected from the AC interface. The method continues by arranging a plurality of switching elements of a second energy conversion module into a discharge configuration to establish an electrical current path from a first terminal of an isolation module, through an inductive element, and to a second terminal of the isolation module. The method also modulates a plurality of switching elements of a first energy conversion module, while maintaining the discharge configuration of the second energy conversion module, to at least partially discharge a DC bus capacitor.

Optimization-based reactive power control in HVDC-connected wind power plants

OpenAIRE

Schönleber, Kevin; Collados Rodríguez, Carlos; Teixeira Pinto, Rodrigo; Ratés Palau, Sergi; Gomis Bellmunt, Oriol

2017-01-01

One application of high–voltage dc (HVdc) systems is the connection of remotely located offshore wind power plants (WPPs). In these systems, the offshore WPP grid and the synchronous main grid operate in decoupled mode, and the onshore HVdc converter fulfills the grid code requirements of the main grid. Thus, the offshore grid can be operated independently during normal conditions by the offshore HVdc converter and the connected wind turbines. In general, it is well known that optimized react...

Modelling and Simulation of VSC-HVDC Connection for Offshore Wind Power Plants

DEFF Research Database (Denmark)

Chaudhary, Sanjay Kumar; Teodorescu, Remus; Rodriguez, Pedro

2010-01-01

Several large offshore wind power plants (WPP) are planned in the seas around Europe. VSC-HVDC is a suitable means of integrating such large and distant offshore WPP which need long submarine cable transmission to the onshore grid. Recent trend is to use large wind turbine generators with full...... scale converters to achieve an optimal operation over a wide speed range. The offshore grid then becomes very much different from the conventional power system grid, in the sense that it is connected to power electronic converters only. A model of the wind power plant with VSC-HVDC connection...

Power Electronics for the Next Generation Wind Turbine System

DEFF Research Database (Denmark)

Ma, Ke

This book presents recent studies on the power electronics used for the next generation wind turbine system. Some criteria and tools for evaluating and improving the critical performances of the wind power converters have been proposed and established. The book addresses some emerging problems...

Performance of Doubly-Fed Wind Power Generators During Voltage Dips

DEFF Research Database (Denmark)

Aparicio, N.; Chen, Zhe; Beltran, H.

The growing of wind generation in Spain has forced its Transmission System Operator (TSO) to release new requirements that establish the amount of reactive power that a wind turbine has to supply to the grid during a voltage dip. Wind turbines equipped with doubly-fed induction generators (DFIG......) can regulate easily the reactive power generated in steady state. However, difficulties appear when reactive power has to be generated during voltage dips. Simulations have been carried out in order to check whether DFIG wind turbines can fulfill the reactive power requirements. Protection system...... commonly employed with DFIG in order to achieve ride-through capabilities including crowbar plays an important role to meet the requirements together with grid-side converter. Resistance associated with the crowbar and its connection duration are crucial at the beginning of the fault. Grid-side converter...

Quantifying offshore wind resources from satellite wind maps: Study area the North Sea

DEFF Research Database (Denmark)

Hasager, Charlotte Bay; Barthelmie, Rebecca Jane; Christiansen, Merete B.

2006-01-01

Offshore wind resources are quantified from satellite synthetic aperture radar (SAR) and satellite scatterometer observations at local and regional scale respectively at the Horns Rev site in Denmark. The method for wind resource estimation from satellite observations interfaces with the wind atlas...... of the Horns Rev wind farm is quantified from satellite SAR images and compared with state-of-the-art wake model results with good agreement. It is a unique method using satellite observations to quantify the spatial extent of the wake behind large offshore wind farms. Copyright © 2006 John Wiley & Sons, Ltd....... analysis and application program (WAsP). An estimate of the wind resource at the new project site at Horns Rev is given based on satellite SAR observations. The comparison of offshore satellite scatterometer winds, global model data and in situ data shows good agreement. Furthermore, the wake effect...

Heat generation by a wind turbine

Energy Technology Data Exchange (ETDEWEB)

Corten, G.P. [ECN Wind, Petten (Netherlands)

2001-01-01

It will be shown that an actuator disk operating in wind turbine mode extracts more energy from the fluid than can be transferred into useful energy. At the Lanchester-Betz limit the decrease of the kinetic energy in the wind is converted by 2 /3 into useful power and by 1 /3 into heat. Behind the wind turbine the outer flow and the flow that has passed the actuator disk will mix. In this process momentum is conserved but part of the kinetic energy will dissipate in heat via viscous shear. 7 refs.

Towards a Reactive Power Oscillation Damping Controller for Wind Power Plant Based on Full Converter Wind Turbines

DEFF Research Database (Denmark)

Knüppel, Thyge; Kumar, Sathess; Thuring, Patrik

2012-01-01

In this paper a power oscillation damping controller (POD) based on modulation of reactive power (Q POD) is analyzed where the modular and distributed characteristics of the wind power plant (WPP) are considered. For a Q POD it is essential that the phase of the modulated output is tightly...... contributes to a collective response. This ability is shown with a 150 wind turbine (WT) WPP with all WTs represented, and it is demonstrated that the WPP contributes to the inter-area damping. The work is based on a nonlinear, dynamic model of the 3.6 MW Siemens Wind Power WT....... controlled to achieve a positive damping contribution. It is investigated how a park level voltage, reactive power, and power factor control at different grid strengths interact with the Q POD in terms of a resulting phase shift. A WPP is modular and distributed and a WPP Q POD necessitate that each WT...

Direct measurements of wind-water momentum coupling in a marsh with emergent vegetation and implications for gas transfer estimates

Science.gov (United States)

Tse, I.; Poindexter, C.; Variano, E. A.

2013-12-01

Among the numerous ecological benefits of restoring wetlands is carbon sequestration. As emergent vegetation thrive, atmospheric CO2 is removed and converted into biomass that gradually become additional soil. Forecasts and management for these systems rely on accurate knowledge of gas exchange between the atmosphere and the wetland surface waters. Our previous work showed that the rate of gas transfer across the air-water interface is affected by the amount of water column mixing caused by winds penetrating through the plant canopy. Here, we present the first direct measurements of wind-water momentum coupling made within a tule marsh. This work in Twitchell Island in the California Delta shows how momentum is imparted into the water from wind stress and that this wind stress interacts with the surface waters in an interesting way. By correlating three-component velocity signals from a sonic anemometer placed within the plant canopy with data from a novel Volumetric Particle Imager (VoPI) placed in the water, we measure the flux of kinetic energy through the plant canopy and the time-scale of the response. We also use this unique dataset to estimate the air-water drag coefficient using an adjoint method.

Fuzzy logic based variable speed wind generation system

Energy Technology Data Exchange (ETDEWEB)

Simoes, M.G. [Sao Paulo Univ., SP (Brazil). Escola Politecnica. PMC - Mecatronica; Bose, B.K. [Tennessee Univ., Knoxville, TN (United States). Dept. of Electrical Engineering; Spiegel, Ronal J. [Environmental Protection Agency, Research Triangle Park, NC (United States). Air and Energy Engineering Research Lab.

1996-12-31

This work demonstrates the successful application of fuzzy logic to enhance the performance and control of a variable speed wind generation system. A maximum power point tracker control is performed with three fuzzy controllers, without wind velocity measurement, and robust to wind vortex and turbine torque ripple. A squirrel cage induction generator feeds the power to a double-sided PWM converter system which pumps the power to a utility grid or supplies to an autonomous system. The fuzzy logic controller FLC-1 searches on-line the generator speed so that the aerodynamic efficiency of the wind turbine is optimized. A second fuzzy controller FLC-2 programs the machine flux by on-line search so as to optimize the machine-converter system wind vortex. Detailed analysis and simulation studies were performed for development of the control strategy and fuzzy algorithms, and a DSP TMS320C30 based hardware with C control software was built for the performance evaluation of a laboratory experimental set-up. The theoretical development was fully validated and the system is ready to be reproduced in a higher power installation. (author) 7 refs., 3 figs., 1 tab.

Power Electronics as key technology in wind turbines

DEFF Research Database (Denmark)

Blaabjerg, Frede

2005-01-01

This paper discuss the development in wind turbines in a two-decade perspective looking at the technology based on track records. Different power electronic topologies for interfacing the wind turbine to the grid are discussed and related to the possibility for the wind turbine to act as a power...

Examining the feasibility of converting New York State’s all-purpose energy infrastructure to one using wind, water, and sunlight

International Nuclear Information System (INIS)

Jacobson, Mark Z.; Howarth, Robert W.; Delucchi, Mark A.; Scobie, Stan R.; Barth, Jannette M.; Dvorak, Michael J.; Klevze, Megan; Katkhuda, Hind; Miranda, Brian; Chowdhury, Navid A.; Jones, Rick; Plano, Larsen; Ingraffea, Anthony R.

2013-01-01

This study analyzes a plan to convert New York State's (NYS's) all-purpose (for electricity, transportation, heating/cooling, and industry) energy infrastructure to one derived entirely from wind, water, and sunlight (WWS) generating electricity and electrolytic hydrogen. Under the plan, NYS's 2030 all-purpose end-use power would be provided by 10% onshore wind (4020 5-MW turbines), 40% offshore wind (12,700 5-MW turbines), 10% concentrated solar (387 100-MW plants), 10% solar-PV plants (828 50-MW plants), 6% residential rooftop PV (∼5 million 5-kW systems), 12% commercial/government rooftop PV (∼500,000 100-kW systems), 5% geothermal (36 100-MW plants), 0.5% wave (1910 0.75-MW devices), 1% tidal (2600 1-MW turbines), and 5.5% hydroelectric (6.6 1300-MW plants, of which 89% exist). The conversion would reduce NYS's end-use power demand ∼37% and stabilize energy prices since fuel costs would be zero. It would create more jobs than lost because nearly all NYS energy would now be produced in-state. NYS air pollution mortality and its costs would decline by ∼4000 (1200–7600) deaths/yr, and $33 (10–76) billion/yr (3% of 2010 NYS GDP), respectively, alone repaying the 271 GW installed power needed within ∼17 years, before accounting for electricity sales. NYS's own emission decreases would reduce 2050 U.S. climate costs by ∼$3.2 billion/yr. - Highlights: ► New York State's all-purpose energy can be derived from wind, water, and sunlight. ► The conversion reduces NYS end-use power demand by ∼37%. ► The plan creates more jobs than lost since most energy will be from in state. ► The plan creates long-term energy price stability since fuel costs will be zero. ► The plan decreases air pollution deaths 4000/yr ($33 billion/yr or 3% of NYS GDP)

Reliability Modeling of Wind Turbines

DEFF Research Database (Denmark)

Kostandyan, Erik

Cost reductions for offshore wind turbines are a substantial requirement in order to make offshore wind energy more competitive compared to other energy supply methods. During the 20 – 25 years of wind turbines useful life, Operation & Maintenance costs are typically estimated to be a quarter...... for Operation & Maintenance planning. Concentrating efforts on development of such models, this research is focused on reliability modeling of Wind Turbine critical subsystems (especially the power converter system). For reliability assessment of these components, structural reliability methods are applied...... to one third of the total cost of energy. Reduction of Operation & Maintenance costs will result in significant cost savings and result in cheaper electricity production. Operation & Maintenance processes mainly involve actions related to replacements or repair. Identifying the right times when...

Control Strategies for the DAB Based PV Interface System.

Directory of Open Access Journals (Sweden)

Hadi M El-Helw

Full Text Available This paper presents an interface system based on the Dual Active Bridge (DAB converter for Photovoltaic (PV arrays. Two control strategies are proposed for the DAB converter to harvest the maximum power from the PV array. The first strategy is based on a simple PI controller to regulate the terminal PV voltage through the phase shift angle of the DAB converter. The Perturb and Observe (P&O Maximum Power Point Tracking (MPPT technique is utilized to set the reference of the PV terminal voltage. The second strategy presented in this paper employs the Artificial Neural Network (ANN to directly set the phase shift angle of the DAB converter that results in harvesting maximum power. This feed-forward strategy overcomes the stability issues of the feedback strategy. The proposed PV interface systems are modeled and simulated using MATLAB/SIMULINK and the EMTDC/PSCAD software packages. The simulation results reveal accurate and fast response of the proposed systems. The dynamic performance of the proposed feed-forward strategy outdoes that of the feedback strategy in terms of accuracy and response time. Moreover, an experimental prototype is built to test and validate the proposed PV interface system.

Techniques for a Wind Energy System Integration with an Islanded Microgrid

Science.gov (United States)

Goyal, Megha; Fan, Yuanyuan; Ghosh, Arindam; Shahnia, Farhad

2016-04-01

This paper presents two different techniques of a wind energy conversion system (WECS) integration with an islanded microgrid (MG). The islanded microgrid operates in a frequency droop control where its frequency can vary around 50 Hz. The permanent magnet synchronous generator (PMSG) based variable speed WECS is considered, which converts wind energy to a low frequency ac power. Therefore it needs to be connected to the microgrid through a back to back (B2B) converter system. One way of interconnection is to synchronize the MG side converter with the MG bus at which it is connected. In this case, this converter runs at the MG frequency. The other approach is to bring back the MG frequency to 50 Hz using the isochronization concept. In this case, the MG side converter operates at 50 Hz. Both these techniques are developed in this paper. The proposed techniques are validated through extensive PSCAD/EMTDC simulation studies.

Impact of Negative Sequence Current Injection by Wind Power Plants

DEFF Research Database (Denmark)

Chaudhary, Sanjay; Göksu, Ömer; Teodorescu, Remus

2013-01-01

This paper presents an analysis of the impact from negative sequence current injection by wind power plants in power systems under steady-state and short-term unbalanced conditions, including faults. The separate positive and negative sequence current control capability of the grid-side converters...... of full scale converter type wind turbines may be utilized to alter voltage imbalance at the point of connection and further into the grid, in turn changing the resultant negative sequence current flow in the grid. The effects of such control actions have been analyzed and discussed through theoretical...

InfraSound from wind turbines : observations from Castle River wind farm. Volume 1

International Nuclear Information System (INIS)

Edworthy, J.; Hepburn, H.

2005-01-01

Although infrasound has been discussed as a concern by groups opposed to wind farm facilities, there is very little information available about infrasound and wind turbines. This paper presented details of a project conducted by VisionQuest, the largest wind power producer in Canada. Three sensor types were used: precision sound analyzer, seismic geophones, and calibrated microphones to take measurements in low, medium and high winds. The project also measured infrasound when the wind farm was not operating. Acquisition geometry was presented, as well as details of apparent attenuations of wind noise. It was noted that high wind noise was a dominant factor and that there was little difference when the wind farm was not operational. It was suggested that turbines have no impact with high wind, since wind noise is not attenuated with distance. It was noted that increased geophone amplitudes indicate high wind coupled motion which is attenuated when the turbines are on. Results indicate that all frequencies showed attenuation with distance. Evidence showed that low frequency sound pressure levels were often lower when the turbines were switched on. Where turbines contributed to sound pressure levels, the magnitude of the contribution was below levels of concern to human health. Ambient sound pressure levels were much higher than contributions from wind turbines. It was concluded that wind itself generates infrasound. Wind turbines generate low levels of infrasound, detectable very close to facilities at low to medium wind speeds. Wind turbines may reduce ambient infrasound levels at high wind speeds by converting the energy from the wind into electricity. refs., tabs., figs

An overview of power electronic converter technology for renewable energy systems

DEFF Research Database (Denmark)

Chen, Zhe

2013-01-01

This chapter presents power electronic technology which is an enabling tool for modern wind and marine energy conversion systems. In this chapter, the main power electronic devices are described. Various power electronic converter topologies are represented, and commonly used modulation schemes...

Wind Velocity and Position Sensor-less Operation for PMSG Wind Generator

Science.gov (United States)

Senjyu, Tomonobu; Tamaki, Satoshi; Urasaki, Naomitsu; Uezato, Katsumi; Funabashi, Toshihisa; Fujita, Hideki

Electric power generation using non-conventional sources is receiving considerable attention throughout the world. Wind energy is one of the available non-conventional energy sources. Electrical power generation using wind energy is possible in two ways, viz. constant speed operation and variable speed operation using power electronic converters. Variable speed power generation is attractive, because maximum electric power can be generated at all wind velocities. However, this system requires a rotor speed sensor, for vector control purpose, which increases the cost of the system. To alleviate the need of rotor speed sensor in vector control, we propose a new sensor-less control of PMSG (Permanent Magnet Synchronous Generator) based on the flux linkage. We can estimate the rotor position using the estimated flux linkage. We use a first-order lag compensator to obtain the flux linkage. Furthermore‚we estimate wind velocity and rotation speed using a observer. The effectiveness of the proposed method is demonstrated thorough simulation results.

Microcontroller Based SPWM Single-Phase Inverter For Wind Power Application

Directory of Open Access Journals (Sweden)

Khin Ohmar Lin

2017-04-01

Full Text Available In this paper microcontroller based sinusoidal pulse width modulation SPWM single-phase inverter is emphasized to constant frequency conversion scheme for wind power application. The wind-power generator output voltage and frequency are fluctuated due to the variation of wind velocity. Therefore the AC output voltage of wind-generator is converted into DC voltage by using rectifier circuit and this DC voltage is converted back to AC voltage by using inverter circuit. SPWM technique is used in inverter to get nearly sine wave and reduce harmonic content. The rating of inverter is 500W single-phase 220V 50 Hz. The required SPWM timing pulses for the inverter are generated from the PIC16F877A microcontroller. Circuit simulation was done by using Proteus 7 Professional and MATLABR 2008 software. The software for microcontroller is implemented by using MPASM assembler.

A new configuration for multilevel converters with diode clamped topology

DEFF Research Database (Denmark)

Nami, A.; Zare, F.; Ledwich, G.

2008-01-01

Due to the increased use of renewable energy and power elctronic applications, more multilevel converters (MLC) are developed. A Neutral Point Clamped (NPC) inverter is one of the most used multilevel topologies for wind turbine (WT) and photovoltaic (PV) applications. One of the most crucial...... of load changes which can avoid neutral point balancing problem in such converters. In addition, the presented topology is suitable for renewable energy systems to boost the low rectified output-voltage. In order to verify the proposed topology, steady state analysis, modelling and simulations are carried...

Novel Modified Elman Neural Network Control for PMSG System Based on Wind Turbine Emulator

Directory of Open Access Journals (Sweden)

Chih-Hong Lin

2013-01-01

Full Text Available The novel modified Elman neural network (NN controlled permanent magnet synchronous generator (PMSG system, which is directly driven by a permanent magnet synchronous motor (PMSM based on wind turbine emulator, is proposed to control output of rectifier (AC/DC power converter and inverter (DC/AC power converter in this study. First, a closed loop PMSM drive control based on wind turbine emulator is designed to generate power for the PMSG system according to different wind speeds. Then, the rotor speed of the PMSG, the voltage, and current of the power converter are detected simultaneously to yield better power output of the converter. Because the PMSG system is the nonlinear and time-varying system, two sets online trained modified Elman NN controllers are developed for the tracking controllers of DC bus power and AC power to improve output performance of rectifier and inverter. Finally, experimental results are verified to show the effectiveness of the proposed control scheme.

Reversible thyristor converters of brushless synchronous compensators

Directory of Open Access Journals (Sweden)

А.М.Galynovskiy

2013-12-01

Full Text Available Behavior of models of three-phase-to-single-phase rotary reversible thyristor converters of brushless synchronous compensators in a circuit simulation system is analyzed. It is shown that combined control mode of opposite-connected thyristors may result in the exciter armature winding short circuits both at the thyristor feed-forward and lagging current delay angles. It must be taken into consideration when developing brushless compensator excitation systems.

Highly reliable wind-rolling triboelectric nanogenerator operating in a wide wind speed range

Science.gov (United States)

Yong, Hyungseok; Chung, Jihoon; Choi, Dukhyun; Jung, Daewoong; Cho, Minhaeng; Lee, Sangmin

2016-01-01

Triboelectric nanogenerators are aspiring energy harvesting methods that generate electricity from the triboelectric effect and electrostatic induction. This study demonstrates the harvesting of wind energy by a wind-rolling triboelectric nanogenerator (WR-TENG). The WR-TENG generates electricity from wind as a lightweight dielectric sphere rotates along the vortex whistle substrate. Increasing the kinetic energy of a dielectric converted from the wind energy is a key factor in fabricating an efficient WR-TENG. Computation fluid dynamics (CFD) analysis is introduced to estimate the precise movements of wind flow and to create a vortex flow by adjusting the parameters of the vortex whistle shape to optimize the design parameters to increase the kinetic energy conversion rate. WR-TENG can be utilized as both a self-powered wind velocity sensor and a wind energy harvester. A single unit of WR-TENG produces open-circuit voltage of 11.2 V and closed-circuit current of 1.86 μA. Additionally, findings reveal that the electrical power is enhanced through multiple electrode patterns in a single device and by increasing the number of dielectric spheres inside WR-TENG. The wind-rolling TENG is a novel approach for a sustainable wind-driven TENG that is sensitive and reliable to wind flows to harvest wasted wind energy in the near future. PMID:27653976

Output power control of two coupled wind generators

Directory of Open Access Journals (Sweden)

A Boukhelifa

2016-09-01

Full Text Available In this paper we are interested to the power control of two wind generators coupled to the network through power converters. Every energy chain conversion is composed of a wind turbine, a gearbox, a Double Fed Induction Generator (DFIG, two PWM converters and a DC bus. The power exchange and the DC voltage are controlled by the use of proportional integral correctors. For our study, initially we have modeled all the components of the one system energy conversion, and then we have simulated its behavior using Matlab/Simulink. In another part of this paper we present the analysis of the interaction and the powerflow between the two aerogenerators following a disturbance due to wind speed on every turbine. Also we have considered a connection fault to the DC bus. In each case the assessment of power brought into play is checked. Simulation tests are established.

Using H∞ to design robust POD controllers for wind power plants

DEFF Research Database (Denmark)

Mehmedalic, Jasmin; Knüppel, Thyge; Østergaard, Jacob

2012-01-01

Large wind power plants (WPPs) can help to improve small signal stability by increasing the damping of electromechanical modes of oscillation. This can be done by adding a power system oscillation damping (POD) controller to the wind power plants, similar to power system stabilizer (PSS......) controllers on conventional generation. Here two different design methods are evaluated for their suitability in producing a robust power system oscillation damping controller for wind power plants with full-load converter wind turbine generators (WTGs). Controllers are designed using classic PSS design and H......∞ methods and the designed controllers evaluated on both performance and robustness. It is found that the choice of control signal has a large influence on the robustness of the controllers, and the best performance and robustness is found when the converter active power command is used as control signal...

Novel wind powered electric vehicle charging station with vehicle-to-grid (V2G) connection capability

International Nuclear Information System (INIS)

Fathabadi, Hassan

2017-01-01

Highlights: • The only wind powered EV charging station reported in the literature. • The charging station maximally converts wind energy into electric energy. • Novel fast and highly accurate MPPT technique implemented in the EV charging station. • The charging station is grid-connected type with vehicle-to-grid (V2G) technology. • The charging station balances load demand in the grid connected to it. - Abstract: In this study, a novel grid-connected wind powered electric vehicle (EV) charging station with vehicle-to-grid (V2G) technology is designed and constructed. The wind powered EV charging station consists of a wind energy conversion system (WECS), a unidirectional DC/DC converter connected to the WECS, a maximum power point tracking (MPPT) controller, 15 bidirectional DC/DC converters dedicated to 15 charging stations provided for charging EVs, and a three-phase bidirectional DC/AC inverter connected to the grid. The contribution of this work is that the grid-connected wind powered EV charging station presented in this work is the only constructed EV charging station reported in the literature that uses wind energy as a renewable resource to produce electric energy for charging EVs, and moreover, it maximally converts wind energy into electric energy because it uses a novel fast and highly accurate MPPT technique proposed in this study. Other works are only simulated models without any new MPPT consideration. It is demonstrated that the constructed wind powered EV charging station is a perfect charging station that not only produces electric energy to charge EVs but also balances load demand in the grid connected to it.

Comparative study of a small size wind generation system efficiency for battery charging

Directory of Open Access Journals (Sweden)

Mayouf Messaoud

2013-01-01

Full Text Available This paper presents an energetic comparison between two control strategies of a small size wind generation system for battery charging. The output voltage of the direct drive PMSG is connected to the battery through a switch mode rectifier. A DC-DC boost converter is used to regulate the battery bank current in order to achieve maximum power from the wind. A maximum powertracking algorithm calculates the current command that corresponds to maximum power output of the turbine. The DC-DC converter uses this current to calculate the duty cycle witch is necessary to control the pulse width modulated (PWM active switching device (IGPT. The system overview and modeling are presented including characteristics of wind turbine, generator, batteries, power converter, control system, and supervisory system. A simulation of the system is performed using MATLAB/SIMULINK.

Laboratory development of wind turbine simulator using variable ...

African Journals Online (AJOL)

user

1*Department of Electronics Engineering, Prof. ... In this paper variable speed induction motor drive using scalar control is interfaced in wind energy conversion ... the wind turbine simulator is used as a necessary tool in research laboratories.

Possibilities and restrictions of wind energy use in one federal state in Germany

International Nuclear Information System (INIS)

Kaltschmitt, M.

1992-01-01

This paper discusses a current political topic, the request for increasing use of wind energy. The objectives of this paper are to evaluate this call in more detail in some parts of the Federal Republic of Germany by analyzing possibilities, restrictions, and production costs of electricity generation from wind energy in Baden-Wurttemberg, an inland state in the southwest of Germany. Based on zones with similar average wind velocities, the theoretical potential to install converters is assessed for each municipality, considering among other things residential areas, highways, roads, rivers, and nature conservation areas as not usable territories. The result is a technical area potential suitable for the installation of wind energy converters. Based on this area potential, a methodological approach is presented that allows the definition and the analysis of strategies of a wind energy use on a high spatial and timely resolution

Pulse-Width-Modulation of Neutral-Point-Clamped Sparse Matrix Converter

DEFF Research Database (Denmark)

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

2007-01-01

input current and output voltage can be achieved with minimized rectification switching loss, rendering the sparse matrix converter as a competitive choice for interfacing the utility grid to (e.g.) defense facilities that require a different frequency supply. As an improvement, sparse matrix converter...... with improved waveform quality. Performances and practicalities of the designed schemes are verified in simulation and experimentally using an implemented laboratory prototype with some representative results captured and presented in the paper....

Power electronic supply system with the wind turbine dedicated for average power receivers

Science.gov (United States)

Widerski, Tomasz; Skrzypek, Adam

2018-05-01

This article presents the original project of the AC-DC-AC converter dedicated to low power wind turbines. Such a set can be a good solution for powering isolated objects that do not have access to the power grid, for example isolated houses, mountain lodges or forester's lodges, where they can replace expensive diesel engine generators. An additional source of energy in the form of a mini-wind farm is also a good alternative to yachts, marinas and tent sites, which are characterized by relatively low power consumption. This article presents a designed low power wind converter that is dedicated to these applications. The main design idea of the authors was to create a device that converts the very wide range input voltage directly to a stable 230VAC output voltage without the battery buffer. Authors focused on maximum safety of using and service. The converter contains the thermal protection, short-circuit protection and overvoltage protection. The components have been selected in such a way as to ensure that the device functions as efficiently as possible.

A proposed national wind power R and D program. [offshore wind power system for electric energy supplies

Science.gov (United States)

Heronemus, W.

1973-01-01

An offshore wind power system is described that consists of wind driven electrical dc generators mounted on floating towers in offshore waters. The output from the generators supplies underwater electrolyzer stations in which water is converted into hydrogen and oxygen. The hydrogen is piped to shore for conversion to electricity in fuel cell stations. It is estimated that this system can produce 159 x 10 to the ninth power kilowatt-hours per year. It is concluded that solar energy - and that includes wind energy - is the only way out of the US energy dilemma in the not too distant future.

Harmonic Mitigation Methods in Large Offshore Wind Power Plants

DEFF Research Database (Denmark)

Kocewiak, Łukasz Hubert; Chaudhary, Sanjay; Hesselbæk, Bo

2013-01-01

Various sources of harmonic problems in large wind power plants (WPPs) and optimized harmonic mitigation methods are presented in this paper. The harmonic problems such as sources of harmonic emission and amplification as well as harmonic stability are identified. Also modern preventive...... and remedial harmonic mitigation methods in terms of passive and active filtering are described. It is shown that WPP components such as long HVAC cables and park transformers can introduce significant low-frequency resonances which can affect wind turbine control system operation and overall WPP stability...... as well as amplification of harmonic distortion. It is underlined that there is a potential in terms of active filtering in modern grid-side converters in e.g. wind turbines, STATCOMs or HVDC stations utilized in modern large WPPs. It is also emphasized that the grid-side converter controller should...

Power density investigations for the large wind turbines' grid-side press-pack IGBT 3L-NPC-VSCs

DEFF Research Database (Denmark)

Senturk, Osman Selcuk; Helle, Lars; Munk-Nielsen, Stig

2012-01-01

-thermal models are required to be derived, implemented, and utilized. In this study, employed as a grid-side medium voltage full-scale voltage source converters (VSCs) in a multi-MW wind turbine, press-pack IGBT three-level neutral-point-clamped VSC (3L-NPC-VSC), 3L active NPC-VSC (3L-ANPC-VSC), and 3L neutral......Power density is the important design criterion in wind turbine converter design provided that satisfactory converter performance is guaranteed. In order to assess a converter in terms of power density, which is dependent on converter electrical and thermal behaviors, converter electro......-point-piloted VSC (3L-NPP-VSC) are characterized in terms of converter operating principles, physical structure, power loss, and DC bus capacitor size for establishing the basis for converter electro-thermal modeling. Via the practical implementations of the converter electro-thermal models in a computation...

Flicker Mitigation by Speed Control of Permanent Magnet Synchronous Generator Variable-Speed Wind Turbines

DEFF Research Database (Denmark)

Hu, Weihao; Zhang, Yunqian; Chen, Zhe

2013-01-01

operation. A new method of flicker mitigation by controlling the rotational speed is proposed. It smoothes the 3p active power oscillations from wind shear and tower shadow effects of the wind turbine by varying the rotational speed of the PMSG. Simulation results show that damping the 3p active power...... oscillation by using the flicker mitigation speed controller is an effective means for flicker mitigation of variable speed wind turbines with full-scale back-to-back power converters and PMSG during continuous operation.......Grid-connected wind turbines are fluctuating power sources that may produce flicker during continuous operation. This paper presents a simulation model of a MW-level variable speed wind turbine with a full-scale back-to-back power converter and permanent magnet synchronous generator (PMSG...

Small Wind Energy Systems

DEFF Research Database (Denmark)

Simões, Marcelo Godoy; Farret, Felix Alberto; Blaabjerg, Frede

2017-01-01

considered when selecting a generator for a wind power plant, including capacity of the AC system, types of loads, availability of spare parts, voltage regulation, technical personal and cost. If several loads are likely inductive, such asphase-controlled converters, motors and fluorescent lights......This chapter intends to serve as a brief guide when someone is considering the use of wind energy for small power applications. It is discussed that small wind energy systems act as the major energy source for residential or commercial applications, or how to make it part of a microgrid...... as a distributed generator. In this way, sources and loads are connected in such a way to behave as a renewable dispatch center. With this regard, non-critical loads might be curtailed or shed during times of energy shortfall or periods of high costs of energy production. If such a wind energy system is connected...

LCL-Filter Design for Robust Active Damping in Grid-Connected Converters

DEFF Research Database (Denmark)

Pena-Alzola, Rafael; Liserre, Marco; Blaabjerg, Frede

2014-01-01

in the grid inductance may compromise system stability, and this problem is more severe for parallel converters. This situation, typical of rural areas with solar and wind resources, calls for robust LCL-filter design. This paper proposes a design procedure with remarkable results under severe grid inductance......Grid-connected converters employ LCL-filters, instead of simple inductors, because they allow lower inductances while reducing cost and size. Active damping, without dissipative elements, is preferred to passive damping for solving the associated stability problems. However, large variations...

Design and development of direct drive generators for wind turbines

International Nuclear Information System (INIS)

Nagrial, M.; Hellany, A.

2011-01-01

This paper discusses various options for wind generators in modern wind turbines without any gearbox. Various power converter configurations are also discussed. The design of modern and efficient variable speed generators is also proposed. The design of a novel permanent magnet generator is also given. (author)

Analysis of horizontal axis wind turbine blade using CFD

African Journals Online (AJOL)

obtained from simulation are compared with the experimental work found in ... Wind turbine rotor interacts with the wind and converts its kinetic energy into ... To get additional information on the flow characteristics a CFD analysis was also ... surface it is better to use NREL 3-D values instead of 2-D experimental values.

Simulation of rectifier voltage malfunction on OWECS, four-level converter, HVDC light link: Smart grid context tool

International Nuclear Information System (INIS)

Seixas, M.; Melício, R.; Mendes, V.M.F.

2015-01-01

Highlights: • Floating offshore wind turbine in deep water. • DC link and voltage malfunction. • Converter topology considered is four-level. • Controllers are based on fractional-order. • Smart grid context. - Abstract: This paper presents a model for the simulation of an offshore wind system having a rectifier input voltage malfunction at one phase. The offshore wind system model comprises a variable-speed wind turbine supported on a floating platform, equipped with a permanent magnet synchronous generator using full-power four-level neutral point clamped converter. The link from the offshore floating platform to the onshore electrical grid is done through a light high voltage direct current submarine cable. The drive train is modeled by a three-mass model. Considerations about the smart grid context are offered for the use of the model in such a context. The rectifier voltage malfunction domino effect is presented as a case study to show capabilities of the model

Investigation of Efficiency and Thermal Performance of The Y-source Converters for a Wide Voltage Range

Directory of Open Access Journals (Sweden)

Brwene Salah Gadalla

2015-12-01

Full Text Available The Y-source topology has a unique advantage of having high voltages gain with small shoot through duty cycles. Furthermore, having the advantage of high modulation index which increase the power density and improve the performance of the converter. In this paper, a collective thermal and efficiency investigation has been performed in order to improve the reliability of the converter. Evaluation of relevant losses as ( switching, conduction, capacitor ESR, core and winding losses , and evaluation of the junction temperature of the devices under 25C ambient temperature. The analysis is done for different voltage gain factors (2, 3, and 4, and different winding factor (4, and 5 using PLECS toolbox. The results shows that the higher the voltage gain and winding factor, the higher power losses and rising in the junction temperature of the device.

Simulation of Lightning Overvoltage Distribution on Stator Windings of Wind Turbine Generators

Institute of Scientific and Technical Information of China (English)

LIU Rong; LIU Xue-zhong; WANG Ying; LI Dan-dan

2011-01-01

This paper analyzes lightning surge on the stator windings of wind turbine generators. The path of lightning in the wind turbines was analyzed. An equivalent circuit model for megawatt direct-driven wind turbine system was developed, in which high-frequency distributed parameters of the blade conducts, tower, power cables and stator windings of generator were calculated based on finite element method, and the models of converter, grounding, loads, surge protection devices and power grid were established. The voltage distribution along stator windings, when struck by lightning with 10/350 ~ts wave form and different amplitude current between 50 kA and 200 kA, was simulated u- sing electro-magnetic transient analysis method. The simulated results show that the highest coil-to-core voltage peak appears on the last coil or near the neutral of stator windings, and the voltage distribution along the windings is non- uniform initially. The voltage drops of each coil fall from first to last coil, and the highest voltage drop appears on the first coil. The insulation damage may occur on the windings under lightning overvoltage. The surge arresters can re- strain the lightning surge in effect and protect the insulation. The coil-to-core voltage in the end of windings is nearly 19.5 kV under the 200 kA lightning current without surge arresters on the terminal of generator, but is only 2.7 kV with arresters.

Comparison of VSC and Z-Source Converter: Power System Application Approach

Directory of Open Access Journals (Sweden)

Masoud Jokar Kouhanjani

2017-01-01

Full Text Available Application of equipment with power electronic converter interface such as distributed generation, FACTS and HVDC, is growing up intensively. On the other hand, various types of topologies have been proposed and each of them has some advantages. Therefore, appropriateness of each converter regarding to the application is a main question for designers and engineers. In this paper, a part of this challenge is responded by comparing a typical Voltage-Source Converter (VSC and Z-Source Converter (ZSC, through high power electronic-based equipment used in power systems. Dynamic response, stability margin, Total Harmonic Distortion (THD of grid current and fault tolerant are considered as assessment criteria. In order to meet this evaluation, dynamic models of two converters are presented, a proper control system is designed, a small signal stability method is applied and responses of converters to small and large perturbations are obtained and analysed by PSCAD/EMTDC.

Adaptive Controller for Drive System PMSG in Wind Turbine

OpenAIRE

Gnanambal; G.Balaji; M.Abinaya

2014-01-01

This paper proposes adaptive Maximum Power Point Tracking (MPPT) controller for Permanent Magnet Synchronous Generator (PMSG) wind turbine and direct power control for grid side inverter for transformer less integration of wind energy. PMSG wind turbine with two back to back voltage source converters are considered more efficient, used to make real and reactive power control. The optimal control strategy has introduced for integrated control of PMSG Maximum Power Extraction, DC li...

Towards a mature offshore wind energy technology - guidelines from the opti-OWECS project

Science.gov (United States)

Kühn, M.; Bierbooms, W. A. A. M.; van Bussel, G. J. W.; Cockerill, T. T.; Harrison, R.; Ferguson, M. C.; Göransson, B.; Harland, L. A.; Vugts, J. H.; Wiecherink, R.

1999-01-01

The article reviews the main results of the recent European research project Opti-OWECS (Structural and Economic Optimisation of Bottom-Mounted Offshore Wind Energy Converters'), which has significantly improved the understanding of the requirements for a large-scale utilization of offshore wind energy. An integrated design approach was demonstrated for a 300 MW offshore wind farm at a demanding North Sea site. Several viable solutions were obtained and one was elaborated to include the design of all major components. Simultaneous structural and economic optimization took place during the different design stages. An offshore wind energy converter founded on a soft-soft monopile was tailored with respect to the distinct characteristics of dynamic wind and wave loading. The operation and maintenance behaviour of the wind farm was analysed by Monte Carlo simulations. With an optimized maintenance strategy and suitable hardware a high availability was achieved. Based upon the experience from the structural design, cost models for offshore wind farms were developed and linked to a European database of the offshore wind energy potential. This enabled the first consistent estimate of cost of offshore wind energy for entire European regions.

A GRID-CONNECTED HYBRID WIND-SOLAR POWER SYSTEM

Directory of Open Access Journals (Sweden)

MAAMAR TALEB

2017-06-01

Full Text Available A hybrid renewable energy system consisting of a photovoltaic generator and a wind driven DC machine is interconnected with the power utilities grid. The interconnection is done through the use of two separate single phase full wave controlled bridge converters. The bridge converters are operated in the “inverter mode of operation”. That is to guaranty the extraction of the real powers from the wind driven generator as well as from the photovoltaic generator and inject them into the power utilities grid. At any pretended surrounding weather conditions, maximum extraction of powers from both renewable energy sources is targeted. This is done through the realization of self-adjusted firing angle controllers responsible of triggering the semiconductor elements of the controlled converters. An active power filter is shunted with the proposed setup to guaranty the sinusoid quality of the power utilities line current. The overall performance of the proposed system has been simulated in MATLAB/SIMULINK environment. Quite satisfactory and encouraging results have been obtained.

Wind Farm Grid Integration Using VSC Based HVDC Transmission - An Overview

DEFF Research Database (Denmark)

Chaudhary, Sanjay Kumar; Teodorescu, Remus; Rodriguez, Pedro

2008-01-01

The paper gives an overview of HVAC and HVDC connection of wind farm to the grid, with an emphasis on Voltage Source Converter (VSC)-based HVDC for large wind farms requiring long distance cable connection. Flexible control capabilities of a VSC-based HVDC system enables smooth integration of wind...... farm into the power grid network while meeting the Grid Code Requirements (GCR). Operation of a wind farm with VSC-based HVDC connection is described....

Gearless wind power generator

Energy Technology Data Exchange (ETDEWEB)

Soederlund, L.; Ridanpaeae, P.; Vihriaelae, H.; Peraelae, R. [Tampere Univ. of Technology (Finland). Lab. of Electricity and Magnetism

1998-12-31

During the wind power generator project a design algorithm for a gearless permanent magnet generator with an axially orientated magnetic flux was developed and a 10 kW model machine was constructed. Utilising the test results a variable wind speed system of 100 kW was designed that incorporates a permanent magnet generator, a frequency converter and a fuzzy controller. This system produces about 5-15% more energy than existing types and stresses to the blades are minimised. The type of generator designed in the project represents in general a gearless solution for slow-speed electrical drives. (orig.)

Flicker Mitigation of Grid Connected Wind Turbines Using STATCOM

DEFF Research Database (Denmark)

Sun, Tao; Chen, Zhe; Blaabjerg, Frede

2004-01-01

to the point of common coupling (PCC) to relieve the flicker produced by grid connected wind turbines and the corresponding control scheme is described in detail. Simulation results show that STATCOM is an effective measure to mitigate the flicker level during continuous operation of grid connected wind......Grid connected wind turbines may produce flicker during continuous operation. In this paper flicker emission of grid connected wind turbines with doubly fed induction generators is investigated during continuous operation. A STATCOM using PWM voltage source converter (VSC) is connected in shunt...

Transient and dynamic control of a variable speed wind turbine with synchronous generator

Energy Technology Data Exchange (ETDEWEB)

Jauch, Clemens [Riso National Laboratory, Wind Energy Department, PO Box 49, DK 4000 Roskilde, (Denmark)

2007-02-14

In this article, a controller for dynamic and transient control of a variable speed wind turbine with a full-scale converter-connected high-speed synchronous generator is presented. First, the phenomenon of drive train oscillations in wind turbines with full-scale converter-connected generators is discussed. Based on this discussion, a controller is presented that dampens these oscillations without impacting on the power that the wind turbine injects into the grid. Since wind turbines are increasingly demanded to take over power system stabilizing and control tasks, the presented wind turbine design is further enhanced to support the grid in transient grid events. A controller is designed that allows the wind turbine to ride through transient grid faults. Since such faults often cause power system oscillations, another controller is added that enables the turbine to participate in the damping of such oscillations. It is concluded that the controllers presented keep the wind turbine stable under any operating conditions, and that they are capable of adding substantial damping to the power system. (Author).

Reliability of wind turbine subassemblies

NARCIS (Netherlands)

Spinato, F.; Tavner, P.J.; Bussel, van G.J.W.; Koutoulakos, E.

2009-01-01

We have investigated the reliability of more than 6000 modern onshore wind turbines and their subassemblies in Denmark and Germany over 11 years and particularly changes in reliability of generators, gearboxes and converters in a subset of 650 turbines in Schleswig Holstein, Germany. We first start

Novel Power Electronics Systems for Wind Energy Applications: Final Report; Period of Performance: August 24, 1999 -- November 30, 2002

Energy Technology Data Exchange (ETDEWEB)

Erickson, R.; Angkititrakul, S.; Al-Naseem, O.; Lujan, G.

2004-10-01

The objective of this work was to develop new approaches to the power electronics of variable-speed wind power systems, with the goal of improving the associated cost of energy. Of particular importance is the converter efficiency at low-wind operating points. Developing converter approaches that maintain high efficiency at partial power, without sacrificing performance at maximum power, is desirable, as is demonstrating an approach that can use emerging power component technologies to attain these performance goals with low projected capital costs. In this report, we show that multilevel conversion is an approach that can meet these performance requirements. In the wind power application, multilevel conversion proves superior to conventional converter technologies because it is callable to high power and higher voltage levels, it extends the range of high converter efficiency to lower wind speeds, and it allows superior low-voltage fast-switching semiconductor devices to be used in high-voltage high-power applications.

Wind structure during mid-latitude storms and its application in Wind Energy

DEFF Research Database (Denmark)

Larsén, Xiaoli Guo; Du, Jianting; Bolanos, Rodolfo

2015-01-01

in Denmark. The extreme wind and wave conditions in the coastal area for wind energy application are important but have rarely been studied in the literature. Our experiments are done to the Danish coasts where the mid-latitude depression systems are causes of the extreme wind and wave conditions....... The numerical modeling is done through an atmosphere-wave coupled system, where the atmospheric model is the Weather Research and Forecasting (WRF) model and the wave model is the Simulating WAves Nearshore (SWAN) model. Measurements from offshore stations, Horns Rev and the FINO platform, as well as satellite...... and the modeling will be presented. Here the “key” is referring both to the application of wind energy and the wind-wave coupling system. The various parameterization of the interface parameter for the atmospheric and wave modeling, the roughness length, has been examined. Data analysis reveals the importance...

Wind-powered asynchronous AC/DC/AC converter system. [for electric power supply regulation

Science.gov (United States)

Reitan, D. K.

1973-01-01

Two asynchronous ac/dc/ac systems are modelled that utilize wind power to drive a variable or constant hertz alternator. The first system employs a high power 60-hertz inverter tie to the large backup supply of the power company to either supplement them from wind energy, storage, or from a combination of both at a preset desired current; rectifier and inverter are identical and operate in either mode depending on the silicon control rectifier firing angle. The second system employs the same rectification but from a 60-hertz alternator arrangement; it provides mainly dc output, some sinusoidal 60-hertz from the wind bus and some high harmonic content 60-hertz from an 800-watt inverter.

Levelized Cost of Energy of the Weptos wave energy converter

DEFF Research Database (Denmark)

Pecher, Arthur; Kofoed, Jens Peter

This report presents the cost of energy calculations of a wave energy array of 90 MW, consisting of 25 x 3.6 MW Weptos wave energy converters. The calculation has been made in analogy with a publically available document presented by the UK government, covering the case of a similar size wind...

Effect of pole zero location on system dynamics of boost converter for micro grid

Science.gov (United States)

Lavanya, A.; Vijayakumar, K.; Navamani, J. D.; Jayaseelan, N.

2018-04-01

Green clean energy like photo voltaic, wind energy, fuel cell can be brought together by microgrid.For low voltage sources like photovoltaic cell boost converter is very much essential. This paper explores the dynamic analysis of boost converter in a continuous conduction mode (CCM). The transient performance and stability analysis is carried out in this paper using time domain analysis and frequency domain analysis techniques. Boost converter is simulated using both PSIM and MATLAB software. Furthermore, state space model obtained and the transfer function is derived. The converter behaviour when a step input is applied is analyzed and stability of the converter is analyzed from bode plot frequency for open loop. Effect of the locations of poles and zeros in the transfer function of boost converter and how the performance parameters are affected is discussed in this paper. Closed loop performance with PI controller is also analyzed for boost converter.

Power system integration and control of variable speed wind turbines

Energy Technology Data Exchange (ETDEWEB)

Eek, Jarle

2009-12-15

A wind power plant is a highly dynamic system that dependent on the type of technology requires a number of automatic control loops. This research deals with modelling, control and analysis related to power system integration of variable speed, pitch controlled wind turbines. All turbine components have been modelled and implemented in the power system simulation program SIMPOW, and a description of the modelling approach for each component is given. The level of model detail relates to the classical modelling of power system components for power system stability studies, where low frequency oscillations are of special importance. The wind turbine model includes a simplified representation of the developed rotor torque and the thrust force based on C{sub p-} and C{sub t} characteristic curves. The mechanical system model represents the fundamental torsional mode and the first mode of blades and tower movements. Two generator technologies have been investigated. The doubly fed induction generator (DFIG) and the stator converter interfaced permanent magnet synchronous generator (PMSG). A simplified model of a 2 level voltage source converter is used for both machine types. The generator converter controllers have been given special attention. All model components are linearized for the purpose of control system design and power system interaction related to small signal stability analysis. Different control strategies discussed in the literature have been investigated with regard to power system interaction aspects. All control parameters are identified using the internal model control approach. The analysis is focused on three main areas: 1. Identification of low damped oscillatory modes. This is carried out by the establishment and discussion of wind turbine modelling. 2. Interaction between control loops. A systematic approach is presented in order to analyse the influence of control loops used in variable speed wind turbines. 3.Impact on power system performance

Optimal Design and Tradeoff Analysis of Planar Transformer in High-Power DC–DC Converters

DEFF Research Database (Denmark)

Ouyang, Ziwei; Thomsen, Ole Cornelius; Andersen, Michael A. E.

2012-01-01

The trend toward high power density, high operating frequency, and low profile in power converters has exposed a number of limitations in the use of conventional wire-wound magnetic component structures. A planar magnetic is a low-profile transformer or inductor utilizing planar windings, instead...... of the traditional windings made of Cu wires. In this paper, the most important factors for planar transformer (PT) design including winding loss, core loss, leakage inductance, and stray capacitance have individually been investigated. The tradeoffs among these factors have to be analyzed in order to achieve...

Critical Clearing Time and Wind Power in Small Isolated Power Systems Considering Inertia Emulation

Directory of Open Access Journals (Sweden)

Elías Jesús Medina-Domínguez

2015-11-01

Full Text Available The stability and security of small and isolated power systems can be compromised when large amounts of wind power enter them. Wind power integration depends on such factors as power generation capacity, conventional generation technology or grid topology. Another issue that can be considered is critical clearing time (CCT. In this paper, wind power and CCT are studied in a small isolated power system. Two types of wind turbines are considered: a squirrel cage induction generator (SCIG and a full converter. Moreover, the full converter wind turbine’s inertia emulation capability is considered, and its impact on CCT is discussed. Voltage is taken into account because of its importance in power systems of this kind. The study focuses on the small, isolated Lanzarote-Fuerteventura power system, which is expected to be in operation by 2020.

Improvement of Microgrid Dynamic Performance under Fault Circumstances using ANFIS for Fast Varying Solar Radiation and Fuzzy Logic Controller for Wind System

Directory of Open Access Journals (Sweden)

Izadbakhsh Maziar

2014-12-01

Full Text Available The microgrid (MG technology integrates distributed generations, energy storage elements and loads. In this paper, dynamic performance enhancement of an MG consisting of wind turbine was investigated using permanent magnet synchronous generation (PMSG, photovoltaic (PV, microturbine generation (MTG systems and flywheel under different circumstances. In order to maximize the output of solar arrays, maximum power point tracking (MPPT technique was used by an adaptive neuro-fuzzy inference system (ANFIS; also, control of turbine output power in high speed winds was achieved using pitch angle control technic by fuzzy logic. For tracking the maximum point, the proposed ANFIS was trained by the optimum values. The simulation results showed that the ANFIS controller of grid-connected mode could easily meet the load demand with less fluctuation around the maximum power point. Moreover, pitch angle controller, which was based on fuzzy logic with wind speed and active power as the inputs, could have faster responses, thereby leading to flatter power curves, enhancement of the dynamic performance of wind turbine and prevention of both frazzle and mechanical damages to PMSG. The thorough wind power generation system, PV system, MTG, flywheel and power electronic converter interface were proposed by using Mat-lab/Simulink.

Smoothing Control of Wind Farm Output by Using Kinetic Energy of Variable Speed Wind Power Generators

Science.gov (United States)

Sato, Daiki; Saitoh, Hiroumi

This paper proposes a new control method for reducing fluctuation of power system frequency through smoothing active power output of wind farm. The proposal is based on the modulation of rotaional kinetic energy of variable speed wind power generators through power converters between permanent magnet synchronous generators (PMSG) and transmission lines. In this paper, the proposed control is called Fluctuation Absorption by Flywheel Characteristics control (FAFC). The FAFC can be easily implemented by adding wind farm output signal to Maximum Power Point Tracking control signal through a feedback control loop. In order to verify the effectiveness of the FAFC control, a simulation study was carried out. In the study, it was assumed that the wind farm consisting of PMSG type wind power generator and induction machine type wind power generaotors is connected with a power sysem. The results of the study show that the FAFC control is a useful method for reducing the impacts of wind farm output fluctuation on system frequency without additional devices such as secondary battery.

Methodologies for Wind Turbine and STATCOM Integration in Wind Power Plant Models for Harmonic Resonances Assessment

DEFF Research Database (Denmark)

Freijedo Fernandez, Francisco Daniel; Chaudhary, Sanjay Kumar; Guerrero, Josep M.

2015-01-01

-domain. As an alternative, a power based averaged modelling is also proposed. Type IV wind turbine harmonic signature and STATCOM active harmonic mitigation are considered for the simulation case studies. Simulation results provide a good insight of the features and limitations of the proposed methodologies.......This paper approaches modelling methodologies for integration of wind turbines and STATCOM in harmonic resonance studies. Firstly, an admittance equivalent model representing the harmonic signature of grid connected voltage source converters is provided. A simplified type IV wind turbine modelling...... is then straightforward. This linear modelling is suitable to represent the wind turbine in the range of frequencies at which harmonic interactions are likely. Even the admittance method is suitable both for frequency and time domain studies, some limitations arise in practice when implementing it in the time...

Design and control of a point absorber wave energy converter with an open loop hydraulic transmission

International Nuclear Information System (INIS)

Fan, YaJun; Mu, AnLe; Ma, Tao

2016-01-01

Highlights: • Point absorber wave energy converter is presented. • Piston pump module captures and converts wave energy. • Hydraulic accumulator stores/releases the surplus energy. • Fuzzy controller adjusts the displacement of hydraulic motor. • Generator outputs meet the electricity demand precisely. - Abstract: In this paper, a point absorber wave energy converter combined with offshore wind turbine is proposed. In the system, the wave energy is captured and converted into hydraulic energy by a piston pump module, which is combined with a wind turbine floating platform, and then the hydraulic energy is converted into electricity energy by a variable displacement hydraulic motor and induction generator. In order to smooth and stabilize the captured wave energy, a hydraulic accumulator is applied to store and release the excess energy. In order to meet the demand power a fuzzy controller is designed to adjust the displacement of hydraulic motor and controlled the output power. Simulation under irregular wave condition has been carried out to verify the validity of the mathematical model and the effectiveness of the controller strategy. The results show that the wave energy converter system could deliver the required electricity power precisely as the motor output torque is controlled. The accumulator could damp out all the fluctuations in output power, so the wave energy would become a dispatchable power source.

Maximum power extraction under different vector-control schemes and grid-synchronization strategy of a wind-driven Brushless Doubly-Fed Reluctance Generator.

Science.gov (United States)

Mousa, Mohamed G; Allam, S M; Rashad, Essam M

2018-01-01

This paper proposes an advanced strategy to synchronize the wind-driven Brushless Doubly-Fed Reluctance Generator (BDFRG) to the grid-side terminals. The proposed strategy depends mainly upon determining the electrical angle of the grid voltage, θ v and using the same transformation matrix of both the power winding and grid sides to ensure that the generated power-winding voltage has the same phase-sequence of the grid-side voltage. On the other hand, the paper proposes a vector-control (power-winding flux orientation) technique for maximum wind-power extraction under two schemes summarized as; unity power-factor operation and minimum converter-current. Moreover, a soft-starting method is suggested to avoid the employed converter over-current. The first control scheme is achieved by adjusting the command power-winding reactive power at zero for a unity power-factor operation. However, the second scheme depends on setting the command d-axis control-winding current at zero to maximize the ratio of the generator electromagnetic-torque per the converter current. This enables the system to get a certain command torque under minimum converter current. A sample of the obtained simulation and experimental results is presented to check the effectiveness of the proposed control strategies. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Power oscillation damping capabilities of wind power plant with full converter wind turbines considering its distributed and modular characteristics

DEFF Research Database (Denmark)

Knüppel, Thyge; Nielsen, Jørgen N.; Jensen, Kim H.

2013-01-01

Wind power plants (WPP) are for power system stability studies often represented with aggregated models where several wind turbines (WT) are aggregated into a single up-scaled model. The advantage is a reduction in the model complexity and the computational time, and for a number of study types...... aggregation is investigated and it is shown that the level of WPP aggregation only has limited impact on the resulting modal damping. The study is based on a non-linear, dynamic model of the 3.6 MW Siemens Wind Power WT....... the accuracy of the results has been found acceptable. A large WPP is, however, both modular and distributed over a large geographical area, and feasibility of aggregating the WTs, thus, have to be reassessed when new applications are introduced for WPPs. Here, the power oscillation damping capabilities...

A control approach for the operation of DG units under variations of interfacing impedance in grid-connected mode

DEFF Research Database (Denmark)

Hoseini, S. Kazem; Pouresmaeil, E.; Hosseinnia, S. H.

2016-01-01

. However, the converter-based DG interface is subjected to the unexpected uncertainties, which highly influence performance of control loop of DG unit and operation of interfaced converter. The interfacing impedance seen by interfaced VSC may considerably vary in power grid, and the stability of interfaced...... converter is highly sensitive to the impacts of this impedance changes; then, DG unit cannot inject appropriate currents. To deal with the instability problem, a control method based on fractional order active sliding mode is proposed in this paper, which is less sensitive to variations of interfacing...... impedance. A fractional sliding surface, which demonstrates the desired dynamics of system is developed and then, the controller is designed in two phases as sliding and reaching phases to keep the control loop stable. Stability issues of the control method are discussed in details and the conditions...

Carbon price and wind power support in Denmark

International Nuclear Information System (INIS)

Gavard, Claire

2016-01-01

This paper aims at characterizing the conditions of wind power deployment in order to infer a carbon price level that would provide wind power with comparable advantage over fossil fuel technologies as effective wind support policies. The analysis is conducted on Denmark after the electricity market liberalization. Probit and tobit techniques are employed to take account of a potential threshold effect. I find that the level and type of the support policy are the dominant drivers of deployment. A feed-in tariff significantly brings more wind power in than a premium policy. The additional capacity installed monthly increases by more than 1 MW for each additional €/MWh of support. This is compared to the effect of the electricity price, investment cost, interest rate and general economic activity. If the policy is a premium, I find that 23€/MWh of support in addition to electricity price is needed to observe the connection of new turbines to the grid with a 0.5 probability. I convert this support level into a carbon price of 27€/ton if wind power competes with coal, and 48€/t if it competes with gas. - Highlights: •I analyze wind power development in Denmark between 2000 and 2010. •I use probit and tobit techniques to assess the determinants of this deployment. •The level and policy type of wind power support are the main drivers. •I deduct the critical level of premium needed to trigger wind power. •I convert this into an equivalent carbon price and I find that it is below 50€/ton.

Turbulent Structure Under Short Fetch Wind Waves

Science.gov (United States)

2015-12-01

maximum 200 words ) Momentum transfer from wind forcing into the ocean is complicated by the presence of surface waves. Wind momentum and energy are...1,520 m from the mouth of the river to the deployment site ). Map created in Google Earth, October 12, 2015, http://www.google.com/earth/. 33...Doppler processing electronics for each transducer uses 14 bit analog to digital converter to digitize the 1.2 MHz acoustic frequency from the four

AC-DC integrated load flow calculation for variable speed offshore wind farms

DEFF Research Database (Denmark)

Zhao, Menghua; Chen, Zhe; Blaabjerg, Frede

2005-01-01

This paper proposes a sequential AC-DC integrated load flow algorithm for variable speed offshore wind farms. In this algorithm, the variable frequency and the control strategy of variable speed wind turbine systems are considered. In addition, the losses of wind turbine systems and the losses...... of converters are also integrated into the load flow algorithm. As a general algorithm, it can be applied to different types of wind farm configurations, and the load flow is related to the wind speed....

Worldwide potential of wind energy

Energy Technology Data Exchange (ETDEWEB)

Flavin, C

1982-01-01

A well-documented discussion is presented dealing with the worldwide potential of wind energy as a source of electrical and mechanical power. It is pointed out that 2% of the solar insolation is converted to wind kinetic energy; it is constantly renewed and nondepletable. Efficiency of windmills are discussed (20 to 40%) and payback periods of less than 5 years are cited. Effects of wind velocity and site location are described. Wind pumps are reviewed and the need for wind pumps, particularly in the developing countries is stressed. The generation of electricity by windmills using small turbines is reviewed and appears promising in areas with wind velocities greater than 12 mi/hr. The development of large windmills and groups of windmills (windfarms) for large scale electrical power is discussed, illustrated, and reviewed (offshore sites included). Environmental and safety problems are considered as well as the role of electrical utilities, government support and research activities. It is concluded that the potential contribution of wind energy is immense and that mechanical windmills may become one of the most important renewable technologies. Electrical generating potential is estimated at 20 to 30% of electrical needs. International programs are discussed briefly. 57 references. (MJJ)

Reliability analysis of grid connected small wind turbine power electronics

International Nuclear Information System (INIS)

Arifujjaman, Md.; Iqbal, M.T.; Quaicoe, J.E.

2009-01-01

Grid connection of small permanent magnet generator (PMG) based wind turbines requires a power conditioning system comprising a bridge rectifier, a dc-dc converter and a grid-tie inverter. This work presents a reliability analysis and an identification of the least reliable component of the power conditioning system of such grid connection arrangements. Reliability of the configuration is analyzed for the worst case scenario of maximum conversion losses at a particular wind speed. The analysis reveals that the reliability of the power conditioning system of such PMG based wind turbines is fairly low and it reduces to 84% of initial value within one year. The investigation is further enhanced by identifying the least reliable component within the power conditioning system and found that the inverter has the dominant effect on the system reliability, while the dc-dc converter has the least significant effect. The reliability analysis demonstrates that a permanent magnet generator based wind energy conversion system is not the best option from the point of view of power conditioning system reliability. The analysis also reveals that new research is required to determine a robust power electronics configuration for small wind turbine conversion systems.

Control of the DC-DC Converter used into Energy Generation System

International Nuclear Information System (INIS)

Bizon, Nicu; Oproescu, Mihai

2006-01-01

This paper presents an investigation of the DC-DC Converter controller used into Energy Generation System. The full bridge is used into an Energy Generation System (EGS) as second power interface between the energy source and the high DC bus. The simulation results show that the DC-DC Converter behavior can be improved using a well designed PI control surface. The used Simulink models for the EGS blocks and some design considerations are presented, too. (authors)

Investigation of steel to dielectric transition using microminiature eddy-current converter

Directory of Open Access Journals (Sweden)

Malikov Vladimir

2018-01-01

Full Text Available The research aims to develop a microminiature converter for electrical steel investigation. The research topic is considered relevant due to the need for evaluation and forecasting of safe operating life of electric steel products. The authors determined the capability to study steel characteristics at different depths based on variations of eddy-current converter amplitude at the steel-dielectric boundary. A microminiature transformer-type converter was designed, which enables to perform local investigations of ferromagnetic materials using eddy-current method based on local studies of the steel electrical conductivity. Having the designed converter as a basis, a hardware-software complex was built to perform experimental studies of steel at the interface boundary. A system was developed for automated converter relocation above the studied object at a specified velocity. Test results are reported for a specimen with continuous and discrete measurements taken at different frequencies. Response dependence of eddy-current converter was found to demonstrate non-linear behavior at steel to dielectric transition. The effect of gap between the eddy-current converter and the test object is investigated.

Advanced control of a doubly-fed induction generator for wind energy conversion

Energy Technology Data Exchange (ETDEWEB)

Poitiers, F.; Bouaouiche, T.; Machmoum, M. [Institut de Recherche en Electronique et Electrotechnique de Nantes Atlantique, rue Christian Pauc, 44306 Nantes (France)

2009-07-15

The aim of this paper is to propose a control method for a doubly-fed induction generator used in wind energy conversion systems. First, stator active and reactive powers are regulated by controlling the machine inverter with three different controllers: proportional-integral, polynomial RST based on pole placement theory and Linear Quadratic Gaussian. The machine is tested in association with a wind-turbine emulator. Secondly a control strategy for the grid-converter is proposed. Simulations results are presented and discussed for each converter control and for the whole system. (author)

Off-shore wind power plant modelling precision and efficiency in electromagnetic transient simulation programs

Energy Technology Data Exchange (ETDEWEB)

Karaagac, U.; Saad, H.; Mahseredjian, J. [Ecole Polytechnique de Montreal, Montreal, QC (Canada); Jensen, S.; Cai, L. [REpower Systems AG, Hamburg (Germany)

2012-07-01

The large number of switching elements in the modular multilevel converter (MMC) is a challenging problem for modeling the MMC-HVDC systems in electromagnetic transient type (EMT-type) programs. The modeling complexity increases even further when MMC-HVDC systems are used to integrate offshore wind farms (OWFs) with power electronics based wind energy converters, such as doubly-fed induction generators (DFIGs). This paper compares the computational performances of various combinations of MMC-HVDC and OWF models. Practical onshore ac fault scenarios are simulated for an OWF composed of DFIG type wind turbines and connected to a practical ac grid through a point-to-point MMC-HVDC system. (orig.)

Flicker Mitigation by Speed Control of Permanent Magnet Synchronous Generator Variable-Speed Wind Turbines

Directory of Open Access Journals (Sweden)

Yanting Hu

2013-07-01

Full Text Available Grid-connected wind turbines are fluctuating power sources that may produce flicker during continuous operation. This paper presents a simulation model of a MW-level variable speed wind turbine with a full-scale back-to-back power converter and permanent magnet synchronous generator (PMSG developed in the simulation tool of PSCAD/EMTDC. Flicker emission of this system is investigated. The 3p (three times per revolution power oscillation due to wind shear and tower shadow effects is the significant part in the flicker emission of variable speed wind turbines with PMSG during continuous operation. A new method of flicker mitigation by controlling the rotational speed is proposed. It smoothes the 3p active power oscillations from wind shear and tower shadow effects of the wind turbine by varying the rotational speed of the PMSG. Simulation results show that damping the 3p active power oscillation by using the flicker mitigation speed controller is an effective means for flicker mitigation of variable speed wind turbines with full-scale back-to-back power converters and PMSG during continuous operation.

Control of offshore wind farms with HVDC grid connection

Energy Technology Data Exchange (ETDEWEB)

Weigel, Stefan; Weise, Bernd; Poeller, Markus [DIgSILENT GmbH, Gomaringen (Germany)

2010-07-01

This paper analyzes various aspects related to the operation of HVDC connected offshore wind farms. The main interest is on the behavior during on- and offshore faults. Different control strategies for VSC-HVDC and ''classical'' thyristor-based HVDC links are presented and analyzed via network simulations. Wind generators with fully-rated converters and wind generators with doubly-fed induction generators are considered as generator types. The feasibility, advantages and disadvantages of the various options are discussed in detail. (orig.)

Doubly Fed Induction Generator Wind Turbines with Fuzzy Controller: A Survey

Directory of Open Access Journals (Sweden)

J. S. Sathiyanarayanan

2014-01-01

Full Text Available Wind energy is one of the extraordinary sources of renewable energy due to its clean character and free availability. With the increasing wind power penetration, the wind farms are directly influencing the power systems. The majority of wind farms are using variable speed wind turbines equipped with doubly fed induction generators (DFIG due to their advantages over other wind turbine generators (WTGs. Therefore, the analysis of wind power dynamics with the DFIG wind turbines has become a very important research issue, especially during transient faults. This paper presents fuzzy logic control of doubly fed induction generator (DFIG wind turbine in a sample power system. Fuzzy logic controller is applied to rotor side converter for active power control and voltage regulation of wind turbine.

Doubly fed induction generator wind turbines with fuzzy controller: a survey.

Science.gov (United States)

Sathiyanarayanan, J S; Kumar, A Senthil

2014-01-01

Wind energy is one of the extraordinary sources of renewable energy due to its clean character and free availability. With the increasing wind power penetration, the wind farms are directly influencing the power systems. The majority of wind farms are using variable speed wind turbines equipped with doubly fed induction generators (DFIG) due to their advantages over other wind turbine generators (WTGs). Therefore, the analysis of wind power dynamics with the DFIG wind turbines has become a very important research issue, especially during transient faults. This paper presents fuzzy logic control of doubly fed induction generator (DFIG) wind turbine in a sample power system. Fuzzy logic controller is applied to rotor side converter for active power control and voltage regulation of wind turbine.

A New Very-High-Efficiency R4 Converter for High-Power Fuel Cell Applications

DEFF Research Database (Denmark)

Nymand, Morten; Andersen, Michael Andreas E.

2009-01-01

of fullbridge switching stages and power transformers, operate in parallel on primary side and in series on secondary side. Current sharing is guaranteed by series connection of transformer secondary windings and three small cascaded current balancing transformers on primary side. The detailed design of a 10 k......W prototype converter is presented. Input voltage range is 30-60 V and output voltage is 800 V. Test results, including voltage- and current waveforms and efficiency measurements, are presented. A record high converter efficiency of 98.2 % is achieved. The proposed R4 boost converter thus constitutes a low...

Modeling of wind turbines with doubly fed generator system

CERN Document Server

Fortmann, Jens

2014-01-01

Jens Fortmann describes the deduction of models for the grid integration of variable speed wind turbines and the reactive power control design of wind plants. The modeling part is intended as background to understand the theory, capabilities and limitations of the generic doubly fed generator and full converter wind turbine models described in the IEC 61400-27-1 and as 2nd generation WECC models that are used as standard library models of wind turbines for grid simulation software. Focus of the reactive power control part is a deduction of the origin and theory behind the reactive current requ

High frequent modelling of a modular multilevel converter using passive components

DEFF Research Database (Denmark)

El-Khatib, Walid Ziad; Holbøll, Joachim; Rasmussen, Tonny Wederberg

2013-01-01

). This means that a high frequency model of the converter has to be designed, which gives a better overview of the impact of high frequency transients etc. The functionality of the model is demonstrated by application to grid connections of off-shore wind power plants. Grid connection of an offshore wind power...... wind power plant employing HVDC. In the present study, a back to back HVDC transmission system is designed in PSCAD/EMTDC. Simulations and results showing the importance of high frequent modeling are presented....... plant using HVDC fundamentally changes the electrical environment for the power plant. Detailed knowledge and understanding of the characteristics and behavior of all relevant power system components under all conditions, including under transients, are required in order to develop reliable offshore...

A High Efficiency Wind Energy System

DEFF Research Database (Denmark)

Khan, M. Z.; Hussain, M. M.; Naveed, M. M.

2012-01-01

In this paper, a wind generator system that employs a Fourphase Interleaved Bi-directional DC / DC Converter, a Selective Harmonic Elimination Sinusoidal Pulse Width Modulation (SHE SPWM) based Inverter and a PermanentMagnet Synchronous Generator (PMSG) is studied. The merits of using the topolog...

Design and operating experience of an ac-dc power converter for a superconducting magnetic energy storage unit

International Nuclear Information System (INIS)

Boenig, H.J.; Nielsen, R.G.; Sueker, K.H.

1984-01-01

The design philosophy and the operating behavior of a 5.5 kA, +-2.5 kV converter, being the electrical interface between a high voltage transmission system and a 30 MJ superconducting coil, are documented in this paper. Converter short circuit tests, load tests under various control conditions, dc breaker tests for magnet current interruption, and converter failure modes are described

Comparison of wind pressure measurements on Silsoe ...

African Journals Online (AJOL)

user

and the over production of turbulent kinetic energy near the sharp edges. The various RANS ... can predict the general wind conditions around building reasonably well except those in the separation regions .... cable to a remote A/D converter.

Systems and methods for an integrated electrical sub-system powered by wind energy

Science.gov (United States)

Liu, Yan [Ballston Lake, NY; Garces, Luis Jose [Niskayuna, NY

2008-06-24

Various embodiments relate to systems and methods related to an integrated electrically-powered sub-system and wind power system including a wind power source, an electrically-powered sub-system coupled to and at least partially powered by the wind power source, the electrically-powered sub-system being coupled to the wind power source through power converters, and a supervisory controller coupled to the wind power source and the electrically-powered sub-system to monitor and manage the integrated electrically-powered sub-system and wind power system.