Enhanced Buck-Boost Three-Level Neutral-Point-Clamped Inverters
DEFF Research Database (Denmark)
Tan, K. K.; Gao, F.; Chiang Loh, Poh
2009-01-01
In traditional three-level neutral-point-clamped (NPC) inverters, a major issue is capacitor voltage imbalance, which results in low order harmonics. The compensation of the capacitor voltages often require additional control complexity, which cannot be conveniently implemented. The "alternative...... method, with the ability to easily adjust for capacitor voltage imbalances. To further improve the boost capability of the three-level NPC inverters, another new topology introduces 2 additional diodes,achieving higher boost performance while totally eliminating thepossibility of capacitor voltage...
Topological Design and Modulation Strategy for Buck-Boost Three-Level Inverters
DEFF Research Database (Denmark)
Gao, Feng; Loh, Poh Chiang; Teodorescu, Remus;
2009-01-01
To date, designed topologies for dc-ac inversion with both voltage buck and boost capabilities are mainly focused on two-level circuitries with extensions to three-level possibilities left nearly unexplored. Contributing to this area of research, this paper presents the design of a number of viable...
Topological Design and Modulation Strategy for Buck-Boost Three-Level Inverters
DEFF Research Database (Denmark)
Teodorescu, Remus; Gao, F.; Blaabjerg, Frede;
2007-01-01
To date, designed topologies for dc-ac inversion with both voltage-buck and boost capabilities are mainly focused on two-level circuitries with extensions to three-level possibilities left nearly unexplored. Contributing to this area of research, this paper presents the design of a number of viable...
Diode-Assisted Buck-Boost Voltage-Source Inverters
DEFF Research Database (Denmark)
Gao, Feng; Loh, Poh Chiang; Teodorescu, Remus;
2009-01-01
This paper proposes a number of diode-assisted buck-boost voltage-source inverters with a unique X-shaped diode-capacitor network inserted between the inverter circuitry and dc source for producing a voltage gain that is comparatively higher than those of other buck-boost conversion techniques...
Component-Minimized Buck-Boost Voltage Source Inverters
DEFF Research Database (Denmark)
Gao, F.; Loh, P.C.; Blaabjerg, Frede;
2007-01-01
the additional voltage relationship between dc input and ac output which is beyond the expectation when continuous inductor current is assumed. These theoretical findings, together with the inverter practicality, have been confirmed in Matlab/PLECS simulations and experimentally using laboratory implemented......This paper presents the design of buck-boost B4 inverters that can be derived from either Ćuk- or SEPIC-derived buck-boost B6 inverters. Unlike traditional inverters, the integration of front-end voltage boost circuitry and inverter circuitry allows it to perform buck-boost voltage inversion....... In order to form a distinct neutral potential in the corresponding voltage boost circuitry for correct B4 inverter operation, necessary modifications are derived step by step. The resulted dc networks with symmetrical placement of passive components allow complete charging and equal energy distribution...
Diode-Assisted Buck-Boost Current Source Inverters
DEFF Research Database (Denmark)
Gao, F.; Cai, Liang; Loh, P.C.
2007-01-01
This paper presents a couple of novel current source inverters (CSIs) with the enhanced current buckboost capability. With the unique diode-inductor network added between current source inverter circuitry and current boost elements, the proposed buck-boost current source inverters demonstrate...... a double current boost capability when comparing with the recently reported buckboost CSIs. For modulating the presented CSIs, two modulation schemes are proposed for achieving either optimized harmonic performance or minimal commutation count, meanwhile keeping the important current buck-boost operation...
Non-Inverting Buck-Boost Converter for Fuel Cell Applications
DEFF Research Database (Denmark)
Schaltz, Erik; Rasmussen, Peter Omand; Khaligh, Alireza
2008-01-01
Fuel cell DC/DC converters often have to be able to both step-up and step-down the input voltage, and provide a high efficiency in the whole range of output power. Conventional negative output buck-boost and non-inverting buck-boost converters provide both step-up and step-down characteristics....... In this paper the non-inverting buck-boost with either diodes or synchronous rectifiers is investigated for fuel cell applications. Most of previous research does not consider the parasitic in the evaluation of the converters. In this study, detailed analytical expressions of the efficiencies for the system...... composed of fuel cell system and interfacing converter, considering the parasitics, are presented. It is concluded that the implementation with synchronous rectifiers provides the highest efficiency in the whole range of the fuel cell power, and its efficiency characteristic is more suitable for fuel cell...
Pulse width modulated buck-boost five-level current source inverters
DEFF Research Database (Denmark)
Blaabjerg, Frede; Gao, F.; Loh, P.C.;
2008-01-01
This paper presents new five-level current source inverters (CSIs) with voltage/current buck-boost capability. Being different from the existing multilevel CSI, the proposed CSIs were first designed to regulate the flowing path of dc input current by controlling two additional active switches, re...
Non-Inverted Buck-Boost Converters with Dual Delta Sigma Modulators
Kobori, Yasunori; Kono, Masashi; Shimizu, Toshihiko; Kobayashi, Haruo
This paper presents a new control circuit to create high-performance non-inverted Buck-Boost converter with dual ⊿∑ modulations. Experimental load regulation, corresponding to load current steps of ±0.5A, is within 45mVpp, and the efficiency without synchronized rectifier is 83% at input voltage 2.5V and load current 0.8A.
Single stage buck-boost DC-AC neutral point clamped inverter
DEFF Research Database (Denmark)
Mo, Wei; Loh, Poh Chiang; Andrew, A.;
2012-01-01
This paper proposes a new single stage buck-boost DC-AC neutral point clamped inverter topology which integrates the cascaded configurations of recently introduced inductor-capacitor-capacitor-transformer impedance source network (by Adamowicz) and classic NPC configuration. As a consequence...... windings thus preventing the core from saturation; lowers the voltage stresses and power losses of inverter switches and reduces the sizes of filtering devices and as well as obtains better output performance compared to the original two-level Z-source inverters. A phase disposition pulse width modulation...
Ahmed, Nabil A.
2011-06-01
This paper presents an advanced power converter employs a sinusoidal voltage absolute value tracking buck-boost DC-DC converter in the first power processing stage and a polarity changing full-bridge inverter in the second stage. The proposed power conversion system has the capability of delivering sinusoidal output and input current with unity power factor and good output voltage regulation. Consequently, the complete voltage regulator system, which is mainly suitable for new energy generation systems as well as energy storage systems, can be constructed compactly and inexpensively without DC link electrolytic capacitor. Also, the paper presents an auxiliary passive resonant circuit for soft switching operation. Simulation results using PSIM software are presented to verify the operation principles and feasibility of the proposed power conversion system.
Closed-loop analysis and control of a non-inverting buck-boost converter
Chen, Zengshi; Hu, Jiangang; Gao, Wenzhong
2010-11-01
In this article, a cascade controller is designed and analysed for a non-inverting buck-boost converter. The fast inner current loop uses sliding mode control. The slow outer voltage loop uses the proportional-integral (PI) control. Stability analysis and selection of PI gains are based on the nonlinear closed-loop error dynamics incorporating both the inner and outer loop controllers. The closed-loop system is proven to have a nonminimum phase structure. The voltage transient due to step changes of input voltage or resistance is predictable. The operating range of the reference voltage is discussed. The controller is validated by a simulation circuit. The simulation results show that the reference output voltage is well-tracked under system uncertainties or disturbances, confirming the validity of the proposed controller.
A Comparison between Buck-Boost Inverter with and without Buffer Inductor
Directory of Open Access Journals (Sweden)
Purwadi Agus Darwito
2012-05-01
Full Text Available The electric vehicle inverter requires an induction motor drive with a high output of voltage and current to reduce the number of batteries used and in turn reduce the vehicle’s weight. In this paper compared two single Phase BuckBoost Inverter (SPBBI, that is between the SPBBI conventional topology with SPBBI new topology uses a buffer inductor. The results of comparison are expected that the new inverter topology can strengthen the voltage greater than the conventional inverter topology. The inverter’s components of capacitor and inductor were reconfigured. The circuit was simulated for various carrier and signal frequencies with various load. The simulation results of the proposed topology compared with the simulation results of conventional topologies commonly used in a variety of frequency and load values. It is shown that the output voltage and current can be strengthened significantly, with a value of more than five times of the output voltage compared to the conventional inverter. The new inverter topology is useful to be implemented for the electric vehicle.
Almasi, Omid Naghash; Fereshtehpoor, Vahid; Khooban, Mohammad Hassan; Blaabjerg, Frede
2017-03-01
In this paper, a new modified fuzzy Two-Level Control Scheme (TLCS) is proposed to control a non-inverting buck-boost converter. Each level of fuzzy TLCS consists of a tuned fuzzy PI controller. In addition, a Takagi-Sugeno-Kang (TSK) fuzzy switch proposed to transfer the fuzzy PI controllers to each other in the control system. The major difficulty in designing fuzzy TLCS which degrades its performance is emerging unwanted drastic oscillations in the converter output voltage during replacing the controllers. Thereby, the fuzzy PI controllers in each level of TLCS structure are modified to eliminate these oscillations and improve the system performance. Some simulations and digital signal processor based experiments are conducted on a non-inverting buck-boost converter to support the effectiveness of the proposed TLCS in controlling the converter output voltage.
Comparison of the Impedance-Source Networks for Two and Multilevel Buck-Boost Inverter Applications
DEFF Research Database (Denmark)
Husev, Oleksandr; Blaabjerg, Frede; Roncero-Clemente, Carlos
2016-01-01
Impedance-source networks are an increasingly popular solution in power converter applications, especially in single-stage buck–boost power conversion to avoid additional front-end dc–dc power converters. In the survey papers published, no analytical comparisons of different topologies have been...... described, which makes it difficult to choose the best option. Thus, the aim of this paper is to present a comprehensive analytical comparison of the impedance-source-based buck–boost inverters in terms of passive component count and semiconductor stress. Based on the waveform of the input current, i...
Space Vector Pulse Width Modulation Strategy for Single-Phase Three-Level CIC T-source Inverter
DEFF Research Database (Denmark)
Shults, Tatiana E.; Husev, Oleksandr O.; Blaabjerg, Frede
2016-01-01
This paper presents a novel space vector pulse-width modulation strategy for a single-phase three-level buck-boost inverter based on an impedance-source network. The case study system is based on T-source inverter with continuous input current. To demonstrate the improved performance of the inver......This paper presents a novel space vector pulse-width modulation strategy for a single-phase three-level buck-boost inverter based on an impedance-source network. The case study system is based on T-source inverter with continuous input current. To demonstrate the improved performance...... of the inverter, the strategy was compared the traditional pulse-width modulation. It is shown that the approach proposed has fewer switching states and does not suffer from neutral point misbalance....
Aalborg Inverter - A New Type of “Buck in Buck, Boost in Boost” Grid-Tied Inverter
DEFF Research Database (Denmark)
Wu, Weimin; Ji, Junhao; Blaabjerg, Frede
2015-01-01
is larger than the magnitude of the ac voltage, it is a voltage-source inverter, and on the contrary it is current-source inverter in the other mode. A 220 V/50 Hz/ 2000 W prototype has been constructed. Simulations and experiments show that it has a good control and system performance....
Aalborg Inverter - A new type of “Buck in Buck, Boost in Boost” Grid-tied Inverter
DEFF Research Database (Denmark)
Wu, Weimin; Blaabjerg, Frede
2013-01-01
, the minimum filtering inductance in the power loop is achieved to reduce the conduction power loss whether in “Boost” or “Buck” mode. In theory, it can achieve higher efficiency than other inverters under the same condition of input DC voltage. The principle of operation is fully illustrated through...
Modulation Schemes of Multi-phase Three-Level Z-Source Inverters
DEFF Research Database (Denmark)
Gao, F.; Loh, P.C.; Blaabjerg, Frede;
2007-01-01
This paper investigates the modulation schemes of three-level multiphase Z-source inverters with either two Z-source networks or single Z-source network connected between the dc sources and inverter circuitry. With the proper offset added for achieving both desired four-leg operation and optimized...... harmonic performance, the proposed modulation schemes of four-leg three-level Z-source inverters can satisfy the expected buck-boost operation under unbalanced modulation conditions. Except of the modulation complexity hidden in the four-leg inverters, five-phase three-level Z-source inverters show totally...... different modulation requirement and output performance. For clearly illustrating the detailed modulation process, time domain analysis instead of the traditional multi-dimensional space vector demonstration is assumed which reveals the right way to insert shoot-through durations in the switching sequence...
Half Load-Cycle Worked Dual Buck-Boost Single-Stage Inverter%半周控制双Buck-Boost单级逆变器
Institute of Scientific and Technical Information of China (English)
嵇保健; 洪峰
2011-01-01
本文提出了一种新颖的双Buck-Boost单级逆变器。单级式逆变器相比传统的两级式逆变器,拓扑结构大大简化,减小了体积重量,降低了损耗,在中小功率场合中的应用具有明显的优势。同时传统单级逆变器不能直接实现升压逆变,在输入母线电压较低时必须增加前级升压电路。针对以上情况,本文通过将两个Buck-Boost电路采用输入串联、输出并联的方式组合,得到一种新型的双Buck-Boost逆变器,并采用半周工作方式使其正常可靠工作,可实现单级直接升压逆变。文中对该电路的工作原理和控制策略进行了详细的分析。仿真和实验验证了新型电路的可行性。该电路在输入母线电压低于输出电压的宽电压范围内均能正常逆变,并取得了较好的波形质量和较高的变换效率。%A novel half load-cycle worked dual Buck-Boost single-stage inverter is presented in this paper.Compared with the traditional two-stage inverter,the single-stage inverter is smaller and lighter due to the structure is greatly simplified as well as the circuit components are reduced a lot.Direct boost DC-AC converter can not be realized by most traditional inverter,so one DC-DC converter has to be added in the front of traditional inverter when input bus voltage is low.In order to obtain one single-stage inverter which can make direct boost inverter come true,two Buck-Boost topologies are combined which are series-wound in input side and parallel connected in output side.Special half load-cycle control mode is used in this new inverter.No matter the input bus voltage is higher or lower than the output voltage,the new inverter works normally and reliably and the output waveform is good,the converter efficiency is high at the same time.Simulation and Experiment verifies those analysis.
Institute of Scientific and Technical Information of China (English)
徐坤; 杨宇; 吴春华; 许富强
2011-01-01
针对功率变换器现有调制方法的不足,提出了一种用于非反相Buck-Boost功率变换器的调制方法,结合脉冲宽度调制和脉冲频率调制,使该功率变换器平滑地在Buck、Buck-Boost、Boost三种模式之间切换,从而在输入电压低于、高于或近似等于输出电压给定值的情况下,使输出电压稳定在给定电压.试验结果验证了该算法的可行性和有效性.%Aiming at the drawbacks of modulation method for power converter, a modulation method which combines pulse width modulation (PWM) with pulse frequency modulation (PFM) for the non-inverting buck-boost converter is proposed in the paper.The power converter can switch smoothly among buck working mode, buck boost working mode and boost working mode in order to regulate the output voltage to the desired output voltage regardless of that the input voltage is less than, greater than or equal to the desired output voltage.The experimental results verify the feasibility and efficiency of the proposed algorithm.
Research on a Three-Phase DC/AC Inverter Based on Buck-Boost Circuit%基于升降压斩波电路的三相DC/AC逆变器研究
Institute of Scientific and Technical Information of China (English)
陈荣
2013-01-01
In order to solve the problems brought about by the common inverter,we propose a novel three-phase DC/AC inverter topology based on buck-boost circuit,and describes how it works.The implementation method applied for three-phase DC/AC inverter using single phase inverter is given.The single-phase inverter and threephase inverter are studied using PSIM software.The parameters adopted in the realistic simulation,waveforms such as load current,voltage of modulation reference and load were given.The simulation results proved that adopting the three-phase DC/AC inverter could achieve a good performance with wide input voltage range and the output voltage of it can gain a line frequency as 50 Hz and the correctness of theoretical analysis.%为了解决常用的逆变器所带来的问题,我们提出一种新型的带升降压功能的三相DC/AC变换器拓扑,并介绍了其工作原理.借助于PSIM仿真软件,对单相和三相电路进行了仿真研究,提出了由单相组成三相电压输出的构成方法.在列出仿真参数的前提下,给出了负载电压,负载电流以及调制给定电压和逆变器输出电压的仿真结果.仿真结果表明三相DC/AC逆变器可以实现50 kHz高频功率变换下宽输入电压范围工频逆变输出,证明了理论分析的正确性.
2013-01-01
This paper analyzes and simulates the Li-ion battery charging process for a solar powered battery management system. The battery is charged using a non-inverting synchronous buck-boost DC/DC power converter. The system operates in buck, buck-boost, or boost mode, according to the supply voltage conditions from the solar panels. Rapid changes in atmospheric conditions or sunlight incident angle cause supply voltage variations. This study develops an electrochemical-based equivalent circuit mod...
Research of an active Buck-Boost Inverter Under Dual Mode Modulation%有源升降压逆变器双模式调制策略研究
Institute of Scientific and Technical Information of China (English)
何耀华; 汤雨; 董仙美
2014-01-01
The inverter used in new energy power generation system should have the ability to adapt a wide range of DC input voltage. Based on the active buck-boost inverter which consists of a full bridge and Boost AC/AC part, two modulation methods were compared: constant boost ratio modulation and dual mode modulation. Along with the relationship of the input DC voltage and the reference AC voltage, the converter completes buck or boost inversion with different equivalent circuits and there are fewer switches working at high frequency in dual mode modulation, which is in favor of the system with high efficiency. The current of the inductor and the current stress of the switches was analyzed in this paper. Experimental results were presented to verify that the proposed topology can achieve dual mode operation with wide range of input voltage.%新能源发电系统要求逆变器具有宽输入电压适应能力，该文基于有源升降压逆变器拓扑，对恒升压比调制和双模态调制两种调制方法进行对比。双模态调制根据不同的直流输入与瞬时的交流输出电压大小关系，使电路呈现出不同的等效电路结构，且每种结构均只有部分开关管高频工作，有利于提高变换效率。还对两种调制下电感电流、开关管电流应力进行分析比较。实验结果表明，该变换器可双模式工作，具有宽输入电压适应能力。
Smooth-Transition Simple Digital PWM Modulator for Four-Switch Buck-Boost Converters
Rodriguez, Alberto; Rodriguez, Miguel; Vazquez, Aitor; Maija, Pablo F.; Sebastian, Javier
2014-08-01
Four Switch non-inverting Buck-Boost (4SBB) converters are extensively used in non-isolated applications where voltage step-up and step-down are required. In order to achieve high efficiency operation it is preferred to control the 4SBB as a Buck or Boost converter, depending on the input/output voltage ratio. However, when input and output voltages are close this approach requires near- unity conversion ratios, which are difficult to achieve in practice. Several alternative operating modes have been proposed in the literature to overcome this issue. In particular, operating the 4SBB as a Buck and Boost at the same time (Buck+Boost mode) has proven to be adequate to achieve near-unity conversion ratios.This paper proposes a simple, hardware-efficient digital pulse width modulator for a 4SBB that enables operation in Buck, Boost and Buck+Boost modes, thus allowing near-unity conversion ratios, while achieving smooth transitions between the different modes. The proposed modulator is simulated with Simulink and experimentally demonstrated using a 500W 4SBB converter with 24V input voltage and 12V-36V output voltage range.
A new Zero Voltage Switching three-level NPC inverter
DEFF Research Database (Denmark)
He, Ning; Chen, Yenan; Xu, Dehong
2015-01-01
A novel Zero Voltage Switching (ZVS) three-level NPC inverter topology using a new ZVS Space Vector Modulation (SVM) scheme is proposed. A detailed operation analysis of ZVS three-level NPC inverter is given. The ZVS condition of the proposed ZVS inverter is derived and it can be achieved of all...... switches in the proposed inverter, which include both the main switches and the auxiliary switches. The design of resonant circuits parameters is also provided. Finally the proposed circuit and ZVS SVM scheme are verified by experimental results and demonstrate a superior performance....
Trans-Z-source Neutral Point Clamped inverter
DEFF Research Database (Denmark)
Mo, W.; Loh, P. C.; Li, D.;
2012-01-01
Transformer based Z-source (trans-Z-source) inverters are recently proposed by extending the traditional Z-source inverter with higher buck-boost capability as well as reducing the passive components at the same time. Multi-Level Z-source inverters are single-stage topological solutions used...... modulation scheme, the three-level trans-Z-source inverter can function with minimum of six device commutations per half carrier cycle (same as the traditional buck NPC inverter), while maintaining to produce the designed volt-sec average and inductive voltage boosting at ac output terminals. The designed...... for buck-boost energy conversion with all the favourable advantages of multi-level switching retained. This paper presents three-level trans-Z-source Neutral Point Clamped (NPC) inverter topology, which achieves both the advantages of trans-Z-source and three-level NPC inverter configuration. With proper...
Directory of Open Access Journals (Sweden)
Chien-Wei Ma
2013-03-01
Full Text Available This paper analyzes and simulates the Li-ion battery charging process for a solar powered battery management system. The battery is charged using a non-inverting synchronous buck-boost DC/DC power converter. The system operates in buck, buck-boost, or boost mode, according to the supply voltage conditions from the solar panels. Rapid changes in atmospheric conditions or sunlight incident angle cause supply voltage variations. This study develops an electrochemical-based equivalent circuit model for a Li-ion battery. A dynamic model for the battery charging process is then constructed based on the Li-ion battery electrochemical model and the buck-boost power converter dynamic model. The battery charging process forms a system with multiple interconnections. Characteristics, including battery charging system stability margins for each individual operating mode, are analyzed and discussed. Because of supply voltage variation, the system can switch between buck, buck-boost, and boost modes. The system is modeled as a Markov jump system to evaluate the mean square stability of the system. The MATLAB based Simulink piecewise linear electric circuit simulation tool is used to verify the battery charging model.
Γ-source Neutral Point Clamped Inverter
DEFF Research Database (Denmark)
Mo, Wei; Loh, Poh Chiang; Blaabjerg, Frede
Transformer based Z-source inverters are recently proposed to achieve promising buck-boost capability. They have improved higher buck-boost capability, smaller size and less components count over Z-source inverters. On the other hand, neutral point clamped inverters have less switching stress...... and better output performance comparing with traditional two-level inverters. Integrating these two types of configurations can help neutral point inverters achieve enhanced votlage buck-boost capability....
2015-01-01
This paper presents a buck-boost converter which is modified to utilize new 600 V gallium nitride (GaN) power semiconductor devices in an application requiring 1200 V devices. The presented buck-boost converter is used as a part of a dc/dc stage in an all-GaN photovoltaic (PV) inverter and it provides a negative voltage for the 3-level neutral-point-clamped (NPC) PWM inverter which is connected to the utility grid. Since in this application the transistor and the diode of ...
Trans-Z-source and Γ-Z-source neutral-point-clamped inverters
DEFF Research Database (Denmark)
Wei, Mo; Loh, Poh Chiang; Blaabjerg, Frede
2015-01-01
Z-source neutral-point-clamped (NPC) inverters are earlier proposed for obtaining voltage buck-boost and three-level switching simultaneously. Their performances are, however, constrained by a trade-off between their input-to-output gain and modulation ratio. This trade-off can lead to high...
Computer simulations of optimum boost and buck-boost converters
Rahman, S.
1982-01-01
The development of mathematicl models suitable for minimum weight boost and buck-boost converter designs are presented. The facility of an augumented Lagrangian (ALAG) multiplier-based nonlinear programming technique is demonstrated for minimum weight design optimizations of boost and buck-boost power converters. ALAG-based computer simulation results for those two minimum weight designs are discussed. Certain important features of ALAG are presented in the framework of a comprehensive design example for boost and buck-boost power converter design optimization. The study provides refreshing design insight of power converters and presents such information as weight annd loss profiles of various semiconductor components and magnetics as a function of the switching frequency.
Computer simulations of optimum boost and buck-boost converters
Rahman, S.
1982-09-01
The development of mathematicl models suitable for minimum weight boost and buck-boost converter designs are presented. The facility of an augumented Lagrangian (ALAG) multiplier-based nonlinear programming technique is demonstrated for minimum weight design optimizations of boost and buck-boost power converters. ALAG-based computer simulation results for those two minimum weight designs are discussed. Certain important features of ALAG are presented in the framework of a comprehensive design example for boost and buck-boost power converter design optimization. The study provides refreshing design insight of power converters and presents such information as weight annd loss profiles of various semiconductor components and magnetics as a function of the switching frequency.
Buck-boost converter feedback controller design via evolutionary search
Sundareswaran, K.; Devi, V.; Nadeem, S. K.; Sreedevi, V. T.; Palani, S.
2010-11-01
Buck-boost converters are switched power converters. The model of the converter system varies from the ON state to the OFF state and hence traditional methods of controller design based on approximate transfer function models do not yield good dynamic response at different operating points of the converter system. This article attempts to design a feedback controller for a buck-boost type dc-dc converter using a genetic algorithm. The feedback controller design is perceived as an optimisation problem and a robust controller is estimated through an evolutionary search. Extensive simulation and experimental results provided in the article show the effectiveness of the new approach.
Integrated buck-boost converter with Matrix-POL architecture
2013-01-01
In this study, integrated buck-boost converter with the Matrix-POL power supply system is proposed. From the simulation results, the validity of the Matrix-POL is revealed. The results revealed that the fast response to the load current and the voltage change can be done with duty and parallel number control by the proposed system.
Series-Connected Buck Boost Regulators
Birchenough, Arthur G.
2005-01-01
A series-connected buck boost regulator (SCBBR) is an electronic circuit that bucks a power-supply voltage to a lower regulated value or boosts it to a higher regulated value. The concept of the SCBBR is a generalization of the concept of the SCBR, which was reported in "Series-Connected Boost Regulators" (LEW-15918), NASA Tech Briefs, Vol. 23, No. 7 (July 1997), page 42. Relative to prior DC-voltage-regulator concepts, the SCBBR concept can yield significant reductions in weight and increases in power-conversion efficiency in many applications in which input/output voltage ratios are relatively small and isolation is not required, as solar-array regulation or battery charging with DC-bus regulation. Usually, a DC voltage regulator is designed to include a DC-to-DC converter to reduce its power loss, size, and weight. Advances in components, increases in operating frequencies, and improved circuit topologies have led to continual increases in efficiency and/or decreases in the sizes and weights of DC voltage regulators. The primary source of inefficiency in the DC-to-DC converter portion of a voltage regulator is the conduction loss and, especially at high frequencies, the switching loss. Although improved components and topology can reduce the switching loss, the reduction is limited by the fact that the converter generally switches all the power being regulated. Like the SCBR concept, the SCBBR concept involves a circuit configuration in which only a fraction of the power is switched, so that the switching loss is reduced by an amount that is largely independent of the specific components and circuit topology used. In an SCBBR, the amount of power switched by the DC-to-DC converter is only the amount needed to make up the difference between the input and output bus voltage. The remaining majority of the power passes through the converter without being switched. The weight and power loss of a DC-to-DC converter are determined primarily by the amount of power
Directory of Open Access Journals (Sweden)
SRDIC, S.
2015-08-01
Full Text Available This paper presents a buck-boost converter which is modified to utilize new 600 V gallium nitride (GaN power semiconductor devices in an application requiring 1200 V devices. The presented buck-boost converter is used as a part of a dc/dc stage in an all-GaN photovoltaic (PV inverter and it provides a negative voltage for the 3-level neutral-point-clamped (NPC PWM inverter which is connected to the utility grid. Since in this application the transistor and the diode of the buck-boost converter need to block the sum of the PV string voltage (which is normally in the range from 150 to 350 V and the dc bus voltage (which is in the order of 400 V, the 1200 V devices or series connection of 600 V devices need to be employed. Currently, 1200 V GaN power semiconductor devices are not commercially available. Therefore, the standard buck-boost converter is modified to enable the use of 600 V GaN devices in this particular application. Based on the proposed converter topology, a PSpice simulation model and a 600 W converter prototype were developed. Both simulation and experimental results show successful operation of the converter.
2014-01-01
The power converter is one of the essential elements for effective use of renewable power sources. This paper focuses on the development of a circuit simulation model for maximum power point tracking (MPPT) evaluation of solar power that involves using different buck-boost power converter topologies; including SEPIC, Zeta, and four-switch type buck-boost DC/DC converters. The circuit simulation model mainly includes three subsystems: a PV model; a buck-boost converter-based MPPT system; and ...
Modeling and Simulation of Buck-Boost Converter with Voltage Feedback Control
2015-01-01
In order to design the control system, it is necessary to have an exact model of buck-boost converter. This paper put forward the transfer function model of buck-boost converter by the state-space average method. The open-loop transfer function model of uncompensated system is deduced according to the mathematic model of the buck-boost converter, the controller is designed according to frequency domain. The phase and magnitude margin of the open-loop system of the buck-boost converter with co...
Nonlinear Phenomena in Buck-Boost Power Factor Correction Converter
Directory of Open Access Journals (Sweden)
Mehrnoosh Vatani
2013-01-01
Full Text Available Buck-Boost Power-Factor-Correction (PFC converter with Average-Current-Model (ACM control is a nonlinear circuit because of the multiplier using and large change in the duty cycle, so its stability analysis must be studied by nonlinear model. In this paper double averaging method is used for describing the model of this converter. By this model we would be able to explain the low frequency dynamics of the system and identify stability boundaries according to circuit parameters and also nonlinear phenomena of this converter are detected.
Schoenfeld, A. D.; Yu, Y.
1973-01-01
Versatile standardized pulse modulation nondissipatively regulated control signal processing circuits were applied to three most commonly used dc to dc power converter configurations: (1) the series switching buck-regulator, (2) the pulse modulated parallel inverter, and (3) the buck-boost converter. The unique control concept and the commonality of control functions for all switching regulators have resulted in improved static and dynamic performance and control circuit standardization. New power-circuit technology was also applied to enhance reliability and to achieve optimum weight and efficiency.
Diode-assisted buck-boost voltage source inverters
DEFF Research Database (Denmark)
Gao, F.; Loh, P.C.; Teodorescu, Remus
2007-01-01
charging and discharging processes of passive components reveals that the dc-link voltage can alternate between two levels, which therefore demonstrate the phenomena that the specified modulation schemes should note. A modulation scheme that can achieve optimized harmonic switching is first designed...... with symmetrical state placement in each switching sequence to avoid unnecessary voltage stress across both passive and active components. To reduce the total commutation count, the designed modulation scheme is then modified without increasing voltage stress. All theoretical findings were verified experimentally...... using a number of scale-down laboratory prototypes....
A TEG Efficiency Booster with Buck-Boost Conversion
Wu, Hongfei; Sun, Kai; Zhang, Junjun; Xing, Yan
2013-07-01
A thermoelectric generator (TEG) efficiency booster with buck-boost conversion and power management is proposed as a TEG battery power conditioner suitable for a wide TEG output voltage range. An inverse-coupled inductor is employed in the buck-boost converter, which is used to achieve smooth current with low ripple on both the TEG and battery sides. Furthermore, benefiting from the magnetic flux counteraction of the two windings on the coupled inductor, the core size and power losses of the filter inductor are reduced, which can achieve both high efficiency and high power density. A power management strategy is proposed for this power conditioning system, which involves maximum power point tracking (MPPT), battery voltage control, and battery current control. A control method is employed to ensure smooth switching among different working modes. A modified MPPT control algorithm with improved dynamic and steady-state characteristics is presented and applied to the TEG battery power conditioning system to maximize energy harvesting. A 500-W prototype has been built, and experimental tests carried out on it. The power efficiency of the prototype at full load is higher than 96%, and peak efficiency of 99% is attained.
Modeling of SVM Diode Clamping Three-Level Inverter Connected to Grid
DEFF Research Database (Denmark)
Guo, Yougui; Zeng, Ping; Zhu, Jieqiong
2011-01-01
PLECS is used to model the diode clamping three-level inverter connected to grid and good results are obtained. First the output voltage SVM is described for diode clamping three-level inverter with loads connected to Y. Then the output voltage SVM of diode clamping three-level inverter is simply...... is very powerful tool to real power circuits and it is very easy to simulate them. They have also verified that SVM control strategy is feasible to control the diode clamping three-level inverter....
Cascaded Buck-Boost AC/AC converter%级联式Buck-Boost AC/AC变换器
Institute of Scientific and Technical Information of China (English)
张友军; 丁明昌; 任永保; 王阿敏; 翁振明
2010-01-01
详细分析了Buck型和Boost型AC/AC变换器的工作原理及其控制方法,在此基础上提出了一种新型级联式Buck-Boost AC/AC变换器及其三模式控制策略.三模式控制策略是比较输入电压与基准输出电压的大小,使得变换器只有3种工作模式:Buck模式、Boost模式和滤波模式.该电路虽然由Buck型和Boost型AC/AC变换器2级变换器级联而成,并采用2级占空比调制,但实际上最多只存在一级功率变换,具有控制简单、变换效率高、开关管电压应力低等优点.仿真结果证明了级联式Buck-Boost AC/AC变换器及其控制策略的可行性和理论分析的正确性.
High Efficient Universal Buck Boost Solar Array Regulator SAR Module
Kimmelmann, Stefan; Knorr, Wolfgang
2014-08-01
The high efficient universal Buck Boost Solar Array Regulator (SAR) module concept is applicable for a wide range of input and output voltages. The single point failure tolerant SAR module contains 3 power converters for the transfer of the SAR power to the battery dominated power bus. The converters are operating parallel in a 2 out of 3 redundancy and are driven by two different controllers. The output power of one module can be adjusted up to 1KW depending on the requirements. The maximum power point tracker (MPPT) is placed on a separate small printed circuit board and can be used if no external tracker signal is delivered. Depending on the mode and load conditions an efficiency of more than 97% is achievable. The stable control performance is achieved by implementing the magnetic current sense detection. The sensed power coil current is used in Buck and Boost control mode.
Buck-Buck- Boost Regulatr (B3R)
Mourra, Olivier; Fernandez, Arturo; Landstroem, Sven; Tonicello, Ferdinando
2011-10-01
In a satellite, the main function of a Power Conditioning Unit (PCU) is to manage the energy coming from several power sources (usually solar arrays and battery) and to deliver it continuously to the users in an appropriate form during the overall mission. The objective of this paper is to present an electronic switching DC-DC converter called Buck-Buck-Boost Regulator (B3R) that could be used as a modular and recurrent solution in a PCU for regulated or un- regulated 28Vsatellite power bus classes. The power conversion stages of the B3R topology are first described. Then theoretical equations and practical tests illustrate how the converter operates in term of power conversion, control loops performances and efficiency. The paper finally provides some examples of single point failure tolerant implementation using the B3R.
Performance Evaluation of Three-Level Z-Source Inverters Under Semiconductor Failure Conditions
DEFF Research Database (Denmark)
Gao, Feng; Loh, P.C.; Vilathgamuwa, D.M.;
2007-01-01
This paper proposes various compensation methods for three-level Z-source inverters under semiconductor failure conditions. Unlike the traditional fault tolerant techniques in three-level inverter by using either an additional phase-leg or collective switching states, the proposed methods simply ...
Performance Evaluation of Three-Level Z-Source Inverters Under Semiconductor-Failure Conditions
DEFF Research Database (Denmark)
Gao, Feng; Loh, Poh Chiang; Blaabjerg, Frede;
2009-01-01
This paper evaluates and proposes various compensation methods for three-level Z-source inverters under semiconductor-failure conditions. Unlike the fault-tolerant techniques used in traditional three-level inverters, where either an extra phase-leg or collective switching states are used......, the proposed methods for three-level Z-source inverters simply reconfigure their relevant gating signals so as to ride-through the failed semiconductor conditions smoothly without any significant decrease in their ac-output quality and amplitude. These features are partly attributed to the inherent boost...... characteristics of a Z-source inverter, in addition to its usual voltage-buck operation. By focusing on specific types of three-level Z-source inverters, it can also be shown that, for the dual Z-source inverters, a unique feature accompanying it is its extra ability to force common-mode voltage to zero even...
Design and comparison of three-level three-phase T-source inverters
DEFF Research Database (Denmark)
Shults, T.; Husev, Oleksandr; Blaabjerg, Frede
2015-01-01
This paper presents guidelines for component design of recently proposed topologies of the three-level three-phase T-source inverters. Two different topologies are considered: T-source inverters with discontinuous input current and T-source inverters with continuous input current. Steady state...
Analysis of Non-minimum Phase in Buck-Boost Converter
2016-01-01
In this paper, relations among the parameters of the non-minimum phase for the Buck-Boost converter are studied. It is demonstrated that when the Buck-Boost converter works in Buck mode, the negative regulation voltage is determined by the converter with the pre-designed inductor and load as the duty ratio D0.382, and the duty ratio has a limited effect on the negative regulation voltage of the converter; when the Buck-Boost converter works in Boost mode，the negative regulation voltage is det...
Common voltage eliminating of SVM diode clamping three-level inverter connected to grid
DEFF Research Database (Denmark)
Guo, Yougui; Zeng, Ping; Zhu, Jieqiong
2011-01-01
A novel method of common voltage eliminating is put forward for SVM diode clamping three-level inverter connected to grid by calculation of common voltage of its various switching states. PLECS is used to model this three-level inverter connected to grid and good results are obtained. First...... analysis of common mode voltage for switching states of diode clamping 3-level inverter is given in detail. Second the common mode voltage eliminating control strategy of SVM is described for diode clamping three-level inverter. Third, PLECS is briefly introduced. Fourth, the modeling of diode clamping...... three-level inverter is presented with PLECS. Finally, a series of simulations are carried out. The simulation results tell us PLECS is a very powerful tool to real power circuits modeling. They have also verified that proposed common mode voltage eliminating control strategy of SVM is feasible...
Modeling and Simulation of Buck-Boost Converter with Voltage Feedback Control
Directory of Open Access Journals (Sweden)
Zhou Xuelian
2015-01-01
Full Text Available In order to design the control system, it is necessary to have an exact model of buck-boost converter. This paper put forward the transfer function model of buck-boost converter by the state-space average method. The open-loop transfer function model of uncompensated system is deduced according to the mathematic model of the buck-boost converter, the controller is designed according to frequency domain. The phase and magnitude margin of the open-loop system of the buck-boost converter with compensator have both been increased. After compensating, this control system has the advantages of small overshoot and short settling time. It can also improve control system’s real time property and anti-interference ability.
Nonlinear program based optimization of boost and buck-boost converter designs
Rahman, S.; Lee, F. C.
1981-01-01
The facility of an Augmented Lagrangian (ALAG) multiplier based nonlinear programming technique is demonstrated for minimum-weight design optimizations of boost and buck-boost power converters. Certain important features of ALAG are presented in the framework of a comprehensive design example for buck-boost power converter design optimization. The study provides refreshing design insight of power converters and presents such information as weight and loss profiles of various semiconductor components and magnetics as a function of the switching frequency.
Three Level Diode Clamped Inverter Fed Induction Motor with Dtc-Svm
Directory of Open Access Journals (Sweden)
V. Ranjith Kumar
2013-09-01
Full Text Available This project presents a three-level diode-clamped inverter feeding an asynchronous motor drive with direct torque control (DTC. The control method is based on DTC operating principles. The stator voltage vector reference is computed from the stator flux and torque errors imposed by the flux and torque controllers. This voltage reference is then generated using a diode-clamped inverter, where each phase of the inverter can be implemented using a dc source, which would be available from fuel cells, batteries, or ultra capacitors. This inverter provides nearly sinusoidal voltages with very low distortion, even without filtering, using fewer switching devices. In addition, the multilevel inverter can generate a high and fixed switching frequency output voltage with fewer switching losses, since only the small power cells of the inverter operate at a high switching rate. Therefore, a high performance and also efficient torque and flux controllers are obtained, enabling a DTC solution for multilevel-inverter-powered motor drives. The Pulse Width modulation technique for an inverter permits to obtain three phase system voltages, which can be applied to the controlled output. Space Vector Modulation (SVPWM principle differs from other PWM processes in the fact that all three drive signals for the inverter will be created simultaneously. The implementation of SVPWM process in digital systems necessitates less operation time and also less program memory. This project uses SVPWM technique for generation of pulses for three-level diode clamped inverter. Simulation is carried out on MATLAB-Simulink software.
Three-Level Z-Source Inverters Using a Single LC Impedance Network
DEFF Research Database (Denmark)
Loh, Poh Chiang; Lim, Sok Wei; Gao, Feng
2007-01-01
two LC impedance networks and two isolated dc sources, which can significantly increase the overall system cost and require a more complex modulator for balancing the network inductive voltage boosting. Offering a number of less costly alternatives, this letter presents the design and control of two...... three-level Z-source inverters, whose output voltage can be stepped down or up using only a single LC impedance network connected between the dc input source and either a neutral-point-clamped (NPC) or dc-link cascaded inverter circuitry. Through careful design of their modulation scheme, both inverters...... can function with the minimum of six device commutations per half carrier cycle (similar to that needed by a traditional buck three-level NPC inverter), while producing the correct volt-sec average and inductive voltage boosting at their ac output terminals. Physically, the designed modulation scheme...
An Effective Wind Energy System based on Buck-boost Controller
Directory of Open Access Journals (Sweden)
N. Prakash
2013-06-01
Full Text Available In Domestic Wind Machines, if the wind speed is low, the output voltage is not sufficient to charge the battery as it is lower than the rated charging voltage of the battery. This limits the overall efficiency of the Wind Machine to 20%. This study proposed to design and develop a Buck Boost Controller for the effective utilization of the wind machine. By implementing a controller based Buck Boost converter, the voltage produced at the lower wind speeds can also be utilized effectively by boosting it to the rated charging voltage of the battery. Also if the wind speed is high (>14 m/s, the DC output voltage will increase to more than 65 V. The converter bucks this high voltage to the nominal battery charging voltage (52 V, thereby protecting the battery from over charging voltage. Thus the effective utilization of the wind machine has been achieved by the use of the proposed Buck Boost Controller.
Modeling and Analysis of Transformerless High Gain Buck-boost DC-DC Converters
Directory of Open Access Journals (Sweden)
Vu Tran
2014-12-01
Full Text Available This paper proposes a transfomerless switched capacitor buck boost converter model, which provides higher voltage gain and higher efficiency when compared to the conventional buck boost converter. The averaged model based on state-space description is analyzed in the paper. The simulation results are presented to confirm the capability of the converter to generate high voltage ratios. The comparison between the proposed model and the traditional model is also provided to reveal the improvement. The proposed converter is suitable for for a wide application which requires high step-up DC-DC converters such as DC micro-grids and solar electrical energy.
A Novel Single Switch Transformerless Quadratic DC/DC Buck-Boost Converter
DEFF Research Database (Denmark)
Mostaan, Ali; A. Gorji, Saman; N. Soltani, Mohsen
2017-01-01
A novel quadratic buck-boost DC/DC converter is presented in this study. The proposed converter utilizes only one active switch and can step-up/down the input voltage, while the existing single switch quadratic buck/boost converters can only work in step-up or step-down mode. First, the proposed ...... converter is analyzed in steady-state. Then, its performance is validated using simulations in MATLAB/SIMULINK software. Finally, an experimental prototype is built for further verification....
Study on Nonlinear Phenomena in Buck-Boost Converter with Switched-Inductor Structure
2013-01-01
The switched-inductor structure can be inserted into a traditional Buck-Boost converter to get a high voltage conversion ratio. Nonlinear phenomena may occur in this new converter, which might well lead the system to be unstable. In this paper, a discrete iterated mapping model is established when the new Buck-Boost converter is working at continuous conduction current-controlled mode. On the basis of the discrete model, the bifurcation diagrams and Poincare sections are drawn and then used t...
PWM Technique for Non-Isolated Three-Phase Buck-Boost PFC Converter
Morizane, Toshimitsu; Shimomori, Wataru; Taniguchi, Katsunori; Kimura, Noriyuki; Ogawa, Masanori
The buck-boost power factor corrected (PFC) converter has the wide range of the dc output voltage. A new non-isolated three-phase hard-switching and a soft-switching buck-boost PFC converter are proposed. Removing the three-phase transformer from the converters makes their size more compact and their costs lower. In addition, the new control method based on the PWM technique is proposed in this paper to achieve the high power factor. Complete soft-switching is also achieved under the discontinuous current mode (DCM) operation.
BLDCM Control System Based on Buck-Boost Converter%基于Buck-Boost变换器驱动的无刷直流电动机控制系统
Institute of Scientific and Technical Information of China (English)
孟武胜; 王波; 何博
2011-01-01
An improved topology of brushless DC motor drive with a Buck-Boost converter before 3 phase inverter,The motor can be controlled by technique-multi-loop. This method can reduce switching losses,the inverter size and cost. Effectiveness and feasibility of the proposed control method was verified by MATLAB/Simulink.%提出在无刷直流电动机的驱动三相逆变桥的输入端加前级降压-升压(Buck-Boost)变换器,采用转速和直流母线电流的多环反馈控制方法实现电机的控制.该方法减少了开关损耗,逆变器尺寸和成本.通过MAT-LAB/Simulink仿真验证了该方法的有效性和可行性.
Control of Grid Connected Photovoltaic System Using Three-Level T-Type Inverter
Zorig, Abdelmalik; Belkeiri, Mohammed; Barkat, Said; Rabhi, Abdelhamid
2016-08-01
Three-level T-Type inverter (3LT2I) topology has numerous advantageous compared to three-level neutral-point-clamped (NPC) inverter. The main benefits of 3LT2I inverter are the efficiency, inverter cost, switching losses, and the quality of output voltage waveforms. In this paper, a photovoltaic distributed generation system based on dual-stage topology of DC-DC boost converter and 3LT2I is introduced. To that end, a decoupling control strategy of 3LT2I is proposed to control the current injected into the grid, reactive power compensation, and DC-link voltage. The resulting system is able to extract the maximum power from photovoltaic generator, to achieve sinusoidal grid currents, and to ensure reactive power compensation. The voltage-balancing control of two split DC capacitors of the 3LT2I is achieved using three-level space vector modulation with balancing strategy based on the effective use of the redundant switching states of the inverter voltage vectors. The proposed system performance is investigated at different operating conditions.
Elimination of zero sequence circulating current between parallel operating three-level inverters
DEFF Research Database (Denmark)
Li, Kai; Wang, Xiaodong; Dong, Zhenhua;
2016-01-01
In order to suppress the zero sequence circulating currents (ZSCCs) between parallel operating three level voltage source inverters with common AC and DC buses, a common mode voltage reduction PWM (CMVR-PWM) technique and neural point potentials (NPPs) control based method is proposed in this paper...
Directory of Open Access Journals (Sweden)
S. Sengottaian
2015-08-01
Full Text Available This study deals with a five phase three level Neutral Point Clamped (NPC inverter fed PMSM drive application. The motor performances depend upon mathematical model so the parameters vary are: noise, common mode voltage, flux variation and harmonic levels of the inverter or motor. Voltage saturation is one of the major problems of a motor which occurs due to speed oscillations, more current fluctuations. This problem can be solved by using PWM technique depends on the reference motor torque and flux. In this study Indirect Field Oriented Control (IFOC NPC inverter is suggested to reduce the voltage saturation. The three level neutral point clamped inverter is widely used for medium and high level applications. Compared with standard two level inverter, this type of NPC inverters have more merits. It generates greater number of levels output waveform in lower harmonic content at the same switching frequency and less voltage stress across the semiconductor switches; finally motor performance and control schemes are verified by using MATLAB/SIMULINK.
Modelling and Simulation of Three Level Inverters for Main Drive of the Plate Mill Rolling Stand
Directory of Open Access Journals (Sweden)
Gasiyarov Vadim R.
2016-01-01
Full Text Available This paper addresses a modelling and a simulation of three level inverters for main drive of the plate mill rolling stand. The main purpose of the article is to develop of a mathematical description of the three level voltage source inverter based on a space vector pulse width modulation and to simulate a consumption current by the main electric drive based on 18-pulse rectification circuit. A twelve-megawatt synchronous motor as a load has been used. The modelling results were simulated at the Matlab/Simulink program. It can allow us to estimate an electromagnetic compatibility of the main electric drive based on transients of the consumption current. The research results can be used to assess the electromagnetic compatibility of powerful three level natural point clamped converters with different types of the space vector pulse width modulation on a load or a grid.
Directory of Open Access Journals (Sweden)
Jaw-Kuen Shiau
2014-08-01
Full Text Available The power converter is one of the essential elements for effective use of renewable power sources. This paper focuses on the development of a circuit simulation model for maximum power point tracking (MPPT evaluation of solar power that involves using different buck-boost power converter topologies; including SEPIC, Zeta, and four-switch type buck-boost DC/DC converters. The circuit simulation model mainly includes three subsystems: a PV model; a buck-boost converter-based MPPT system; and a fuzzy logic MPPT controller. Dynamic analyses of the current-fed buck-boost converter systems are conducted and results are presented in the paper. The maximum power point tracking function is achieved through appropriate control of the power switches of the power converter. A fuzzy logic controller is developed to perform the MPPT function for obtaining maximum power from the PV panel. The MATLAB-based Simulink piecewise linear electric circuit simulation tool is used to verify the complete circuit simulation model.
A Novel Quadratic Buck-Boost DC-DC Converter without Floating Gate-Driver
DEFF Research Database (Denmark)
Mostaan, Ali; A. Gorji, Saman; N. Soltani, Mohsen
2016-01-01
for floating gate driver. In addition, the voltage stress of one of the switches is lower than the existing quadratic buck-boost converters. Performance of the analytical results is validated using both simulation in MATLAB/SIMULINK and experimental tests where the proposed converter is evaluated in both buck...
Analysis of Non-minimum Phase in Buck-Boost Converter
Directory of Open Access Journals (Sweden)
Huang Jinfeng
2016-01-01
Full Text Available In this paper, relations among the parameters of the non-minimum phase for the Buck-Boost converter are studied. It is demonstrated that when the Buck-Boost converter works in Buck mode, the negative regulation voltage is determined by the converter with the pre-designed inductor and load as the duty ratio D0.382, and the duty ratio has a limited effect on the negative regulation voltage of the converter; when the Buck-Boost converter works in Boost mode，the negative regulation voltage is determined jointly by the converter with its pre-designed inductor, load and duty cycle, for which performs that the higher the output voltage is (i.e., the greater the duty ratio is，the more severe undershoot of the voltage will be. The conclusion of this paper has a guidance meaning for decreasing the negative regulation voltage of the Buck-Boost converter. Finally the correctness of the analysis for the non-minimum phase is verified by simulations and experiments.
Analisys of Current-Bidirectional Buck-Boost Based Automotive Switch-Mode Audio Amplifier
DEFF Research Database (Denmark)
Bolten Maizonave, Gert; Andersen, Michael A. E.; Kjærgaard, Claus;
2011-01-01
The following study was carried out in order to assess quantitatively the performance of the buck-boost converter when used as switch-mode audio amplifier. It comprises of, to begin with, the delimitation of design criteria based on the state-ofthe- art solution, which is based in a differential ...
Three-Level AC-DC-AC Z-Source Converter Using Reduced Passive Component Count
DEFF Research Database (Denmark)
Loh, Poh Chiang; Gao, Feng; Tan, Pee-Chin;
2007-01-01
This paper presents a three-level ac-dc-ac Z-source converter with output voltage buck-boost capability. The converter is implemented by connecting a low cost front-end diode rectifier to a neutral-point-clamped inverter through a single X-shaped LC impedance network. The inverter is controlled...... to switch with a three-level output voltage, where the middle neutral potential is uniquely tapped from the star-point of a wye-connected capacitive filter placed before the front-end diode rectifier for input current filtering. Through careful control, the resulting converter can accurately produce...... the correct volt-sec average at its output, while simultaneously achieving inductive voltage boosting. More interestingly, these performance features are achieved with no increase in the number of semiconductor commutations, and hence no increase in switching losses. The proposed converter therefore offers...
DEFF Research Database (Denmark)
Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael A. E.
2011-01-01
In this paper, a circuit-level decoupling modulation strategy is proposed for the three-level (TL) neutral-point-clamped (NPC) inverters. With the proposed modulation scheme, the TL-NPC inverter can be decoupled into two three-level Buck converters in each defined operating section, which makes...... without any feedback control. The simulation results show the validity of theoretical analysis....
Directory of Open Access Journals (Sweden)
S. Radha Krishna Reddy
2012-06-01
Full Text Available Multilevel inverters are increasingly being used in high-power medium voltage applications due to their superior performance compared to two-level inverters. Among various modulation techniques for a multilevel inverter, the space vector pulse width modulation (SVPWM is widely used. This paper deals with the three-phase three-level inverter fed induction motor drive. The proposed scheme deals with the development and implementation of three phase three level inverter to improve the efficiency and reliability of the inverter. Simulation tests have been carried out to examine the operating characteristics of the completed three-phase three-level inverter driving induction motor and an RL load with different switching devices and are compared
Direct Torque Control for Three-Level Neutral Point Clamped Inverter-Fed Induction Motor Drive
Directory of Open Access Journals (Sweden)
M. K. Sahu
2012-04-01
Full Text Available Direct torque control (DTC is a control technique in AC drive systems to obtain high performance torque control. The classical DTC drive contains a pair of hysteresis comparators and suffers from variable switching frequency and high torque ripple. These problems can be solved by using space vector depending on the reference torque and flux. In this paper the space vector modulation technique is applied to the three-level Neutral Point Clamped (NPC inverter control in the proposed DTC-based induction motor drive system, resulting to a significant reduce of torque ripple. Three-level neutral point clamped inverters have been widely used in medium voltage applications. This type of inverters have several advantages over standard two-level VSI, such as greater number of levels in the output voltage waveforms, less harmonic distortion in voltage and current waveforms and lower switching frequencies. This paper emphasizes the derivation of switching states using the Space Vector Pulse Width Modulation (SVPWM technique. The control scheme is implemented using Matlab/Simulink. Experimental results using dSPACE validate the steady-state and the dynamic performance of the proposed control strategy.
A new approach to improve dynamic characteristics of digitally controlled buck-boost dc-dc converter
2010-01-01
This paper presents a new digital control buck-boost dc-dc converter with bias model to improve dynamic characteristics. The buck-boost converter needs to respond appropriately to changing input voltage and load change with wide input voltage. This approach makes adjustment to the bias value by input voltage and output current. As a result, it is revealed that not only the dynamic characteristics but also static characteristics can be improved and it is effective for wide range input voltage.
Fractional order Buck-Boost converter in CCM: modelling, analysis and simulations
Wang, Faqiang; Ma, Xikui
2014-12-01
In this paper, the modelling, analysis and the power electronics simulator (PSIM) simulations of the fractional order Buck-Boost converter operating in continuous conduction mode (CCM) operation are investigated. Based on the three-terminal switch device method, the average circuit model of the fractional order Buck-Boost converter is established, and the corresponding DC equivalent circuit model and AC small signal equivalent circuit model are presented. And then, the equilibrium point and the transfer functions are derived. It is found that the equilibrium point is not influenced by the inductor's or the capacitor's order, but both these orders are included in the derived transfer functions. Finally, the comparisons between the theoretical analysis and the PSIM simulations are given for confirmation.
Directory of Open Access Journals (Sweden)
Sreedhar Madichetty
2014-02-01
Full Text Available In this paper it proposes a high efficient soft-switching scheme based on zero-voltage-switching (ZVS and zero-current-switching(ZCS principle operated with a simple auxiliary circuit extended range for the front-end isolated DC-AC-DC-AC high power converter with an three phase three level diode clamped multi level inverter by using Minority Charge Carrier inspired optimization technique (MCI with Total Harmonic Distortion(THD,Switching losses, Selective harmonic elimination maintaining with its fundamental as an objective function. Input to the inverter is obtained by the photo voltaic cells and with battery bank. The switching scheme is optimized by MCI technique, analyzed and executed in Matlab and implemented with a digital signal processor (DSP .Experimental results with different loads have observed and shows its effectives, robustness of the applied technique.
Buck-Boost/Forward Hybrid Converter for PV Energy Conversion Applications
2014-01-01
This paper presents a charger and LED lighting (discharger) hybrid system with a PV array as its power source for electronic sign indicator applications. The charger adopts buck-boost converter which is operated in constant current mode to charge lead-acid battery and with the perturb and observe method to extract maximum power of PV arrays. Their control algorithms are implemented by microcontroller. Moreover, forward converter with active clamp circuit is operated in voltage regulation cond...
Comparative Analysis of PWM Techniques for Three Level Diode Clamped Voltage Source Inverter
Directory of Open Access Journals (Sweden)
Zulkifilie Bin Ibrahim
2014-07-01
Full Text Available Multilevel inverters are increasingly being used in high-power medium voltage industrial drive applications due to their superior performance compared to conventional two-level inverters. Thre are a number of Pulse width modulation (PWM techniques applied in recent years. The most widely applied PWM techniques are Sine Pulse Width Modulation (SPWM and Space Vector Pulse Width Modulation (SVPWM. SPWM is the most simple modulation technique that can realize easily in analog circuit. However, it has some drawbacks such as higher total harmonic distortion (THD, lower effective DC utilization and lower switching frequency. Space vector pulse width modulation (SVPWM is widely used because of their easier digital realization and better DC bus utilization and lower THD. The complexity is due to the difficulty in determining the reference vector location, on times calculation, and switching states selection. This paper presents a simple SVPWM algorithm for diode clamped three level inverters based on standard two-level SVPWM which can easily determine the location of reference vector, calculate the on-times, the selection of switching states. Three level diode clamped inverter (3LDCI using space vector modulation technique has been modeled and simulated using MATLAB/SIMULINK and Origin 6.1 with a passive R-L load that can be extended to any level. Simulation results are presented to verify the proposed SVPWM control in terms of THD. The results are compared with conventional sinusoidal pulse width modulation (SPWM where SVPWM shows better performance than SPWM in terms of THD.
Modeling of Busbars in High Power Neutral Point Clamped Three-Level Inverters
Institute of Scientific and Technical Information of China (English)
YI Rung; ZHAO Zhengming; ZHONG Yulin
2008-01-01
The busbars in high power neutral point clamped three-level inverters are modeled using the Maxwell Q3D Extractor software, which is based on the partial element equivalent circuits method. The equivalent circuits of the busbars and devices model are simulated in the electric simulator PSIM to analyze the effects of the parasitic inductance on the switching characteristics of the integrated gate commutatedthyristor (IGCT) in different topology positions. The simulation results agree well with the measured imped-ance analyzer results and the IGCT test results, which proves the effectiveness of the modeling method for the large, complex busbars.
Space vector modulation strategy for neutral-point voltage balancing in three-level inverter systems
DEFF Research Database (Denmark)
Choi, Uimin; Lee, Kyo Beum
2013-01-01
This study proposes a space vector modulation (SVM) strategy to balance the neutral-point voltage of three-level inverter systems. The proposed method is implemented by combining conventional symmetric SVM with nearest three-vector (NTV) modulation. The conventional SVM is converted to NTV...... modulation by properly adding or subtracting a minimum gate-on time. In addition, using this method, the switching frequency is reduced and a decrease of switching loss would be yielded. The neutral-point voltage is balanced by the proposed SVM strategy without additional hardware or complex calculations...
DEFF Research Database (Denmark)
Loh, P.C.; Blaabjerg, Frede; Wong, C.P.
2007-01-01
Z-source neutral-point-clamped (NPC) inverter has recently been proposed as an alternative three-level buck-boost power conversion solution with an improved output waveform quality. In principle, the designed Z-source inverter functions by selectively "shooting through" its power sources, coupled...... to the inverter using two unique Z-source impedance networks, to boost the inverter three-level output waveform. Proper modulation of the new inverter would therefore require careful integration of the selective shoot-through process to the basic switching concepts to achieve maximal voltage-boost, minimal...... that have been presented. The presented strategies are also comparatively evaluated to identify their individual advantages and disadvantages, which are subsequently summarized in a comprehensive reference table. Last, simulation and experimental results are included for validating the performances...
Achalhi, A.; Bezza, M.; Belbounaguia, N.; Boujoudi, B.
2017-03-01
The performances of Direct Torque Control (DTC) of Induction machine are highly related to the inverter used therewith. The purpose of this paper is to highlight the efficiency of the space vector modulation (SVM) control of three level inverter associated with the direct torque control. The first part of this work is devoted to present the mathematical models of the DTC associated with 2-levels inverter then 3-levels inverter. Simulations on Matlab/Simulink will allow a comparative study to highlight advantages of the use of three levels inverter. The second part is devoted to the improvement of the DTC associated with a 3-levels inverter by application of the space vector modulation strategy (SVM) in order to manage the switching frequency and reduce harmonics. The efficiency of this solution will be attested by simulation on Matlab/Simulink.
BUCK-BOOST DC/DC变换器RHP零点研究%Right Half Plane Zero Spot Research of BUCK-BOOST DC/DC Converter
Institute of Scientific and Technical Information of China (English)
周习祥
2010-01-01
对于BUCK-BOOST DC/DC变换器,如何获得较大的稳定裕度和良好的高频瞬态性能一直以来都是令研究人员棘手的问题.要使这种变换器稳定工作,往往需要在一个很低的频率下就滑离控制电路的增益,文章基于变换器的占空比控制方式与电流控制公式分析了右半平面零点的动态特性,为提高电源系统的稳定性提供了理论依据.
级联Buck-Boost PFC变换器建模及仿真%Modeling and Simulation of Cascaded Buck-Boost AC-DC Converter
Institute of Scientific and Technical Information of China (English)
郭学军; 刘以建
2016-01-01
文中采用状态空间平均法对级联Buck-Boost AC-DC变换器进行了小信号建模分析,提出了一种基于瞬时功率守恒的新的平均电流控制(ACC)技术.通过这种新的控制技术能够使得输入电流波形接近正弦波且与输入电压同相位,总的谐波扰动小于3％.最后通过PSIM仿真实验,验证了这种新的控制方法的可行性和优越性.
Current Sensorless Control Algorithm for Single-Phase Three-Level NPC Inverter
Directory of Open Access Journals (Sweden)
Suzdalenko Alexander
2014-12-01
Full Text Available The current measurement is becoming a challenging task in power converters operating at high switching frequencies, moreover traditional control system requires two control loops - first (slow regulates DC-link voltage, second (fast controls the shape of current, that all together results in complicated transfer function and long transition periods. The current sensorless control (CSC allows neglecting the mentioned problems. This research for the first time presents the solution of CSC implementation in single-phase three-level neutral point clamped inverter. Mathematical equations were defined for inductor current peaks and transistor conduction time during discontinuous and continuous conduction modes, as well as major problem of current fitting between different voltage levels (consequently with different current peak-to-peak values was solved, providing two solutions - pre-fitting and post-fitting trajectories. The verification of our theoretical assumptions and analytical equations was confirmed by the simulation analysis. Challenges of real experiments are discussed in the conclusion.
Analysis of current-bidirectional buck-boost based switch-mode audio amplifier
DEFF Research Database (Denmark)
Bolten Maizonave, Gert; Andersen, Michael A. E.; Kjærgaard, Claus;
2011-01-01
in a differential mode buckbased amplifier with a boost converter as power supply. The averaged switch modelling of the differential mode current bidirectional topology is also used, in order to analyze the steady state and frequency-wise behaviour of this converter and parameterize it to meet the design criteria......The following studdy was carried out in order to assses quantitatively the performannce of the buck--boost converter whhen used as swiitch-mode audio amplifier. It comprises of, to beggin with, the de limitation of design criteria bassed on the state of-the-art solution, which is based...
Evaluation of Arm Processor-based Bionic Intelligent Controller for a Buck-boost Converte
Directory of Open Access Journals (Sweden)
M.V. Mini
2015-07-01
Full Text Available This study focuses on performance-comparison of different tuning methods for a PI controller applied to a buck-boost converter. Comparison between the controllers is made by analysis of design methodology implementation issues and empirically measured performance. Design of PI controller is based on frequency response of the converter. The optimization of PI controller is based on ant colony algorithm. Experimental results show that, tuning the PI controller using ACO algorithm gave better performance than the conventional algorithm. This is mainly due to the fact ACO is capable of reducing the overshoot without oscillation.
Analysis and design of an adaptive multi-loop controlled two winding buck/boost regulator
Mahmoud, M. F.; Lee, F. C.
1979-01-01
Small signal low frequency linear average model is derived for a multi-loop controlled two-winding buck/boost converter employing average techniques and the describing function method. The model reveals that a well-designed multi-loop control can provide a second-order zero adaptive to output filter parameter changes due to component tolerances, temperature changes, aging, and the effect of duty cycle modulation. It also can provide stabilization effect by shifting the positive zero to the left-half S-plane. Design guidelines are formulated to optimize regulator-loop dependent characteristics.
A New Approach for High Efficiency Buck-Boost DC/DC Converters Using Series Compensation
Itoh, Jun-Ichi; Fujii, Takashi
This paper proposes a novel concept for non-isolated buck-boost DC/DC converter and control method. The proposed concept uses a series connection converter that only regulates the differential voltage between the input and output voltage. As a result, the power converter capacity is decreased. Moreover, the proposed circuit has advantages such as improved efficiency and losses reduction. The fundamental operation, control method, and design method of the proposed circuit are described in this paper. In addition, the validity of the proposed circuit is confirmed by carrying out simulations and experiments.
Study on Nonlinear Phenomena in Buck-Boost Converter with Switched-Inductor Structure
Directory of Open Access Journals (Sweden)
Hongchen Liu
2013-01-01
Full Text Available The switched-inductor structure can be inserted into a traditional Buck-Boost converter to get a high voltage conversion ratio. Nonlinear phenomena may occur in this new converter, which might well lead the system to be unstable. In this paper, a discrete iterated mapping model is established when the new Buck-Boost converter is working at continuous conduction current-controlled mode. On the basis of the discrete model, the bifurcation diagrams and Poincare sections are drawn and then used to analyze the effects of the circuit parameters on the performances. It can be seen clearly that various kinds of nonlinear phenomena are easy to occur in this new converter, including period-doubling bifurcation, border collision bifurcation, tangent bifurcation, and intermittent chaos. Value range of the circuit parameters that may cause bifurcations and chaos are also discussed. Finally, the time-domain waveforms, phase portraits, and power spectrum are obtained by using Matlab/Simulink, which validates the theoretical analysis results.
High-accuracy current sensing circuit with current compensation technique for buck-boost converter
Rao, Yuan; Deng, Wan-Ling; Huang, Jun-Kai
2015-03-01
A novel on-chip current sensing circuit with current compensation technique suitable for buck-boost converter is presented in this article. The proposed technique can sense the full-range inductor current with high accuracy and high speed. It is mainly based on matched current mirror and does not require a large proportion of aspect ratio between the powerFET and the senseFET, thus it reduces the complexity of circuit design and the layout mismatch issue without decreasing the power efficiency. The circuit is fabricated with TSMC 0.25 µm 2P5M mixed-signal process. Simulation results show that the buck-boost converter can be operated at 200 kHz to 4 MHz switching frequency with an input voltage from 2.8 to 4.7 V. The output voltage is 3.6 V, and the maximum accuracy for both high and low side sensing current reaches 99% within the load current ranging from 200 to 600 mA.
DEFF Research Database (Denmark)
Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael A. E.
2013-01-01
inverters, but also reduces the switching loss of the inverter along with an inherent neutral point (NP) voltage control. Based on a circuit-level decoupling concept, the NPC inverter can be decoupled into two three-level Buck converters in every defined operating section, and thereby the controller design...... carrier wave needed for pulse width modulating. Same as a space vector modulation, the maximum modulation index, 1.1547, can be attainable by the proposed scheme. Moreover, compared to conventional continuous sinusoidal pulse width modulation, using this technique here the switching losses of the devices...
Dual Z-Source Inverter With Three-Level Reduced Common-Mode Switching
DEFF Research Database (Denmark)
Gao, Feng; Loh, Poh Chiang; Blaabjerg, Frede;
2007-01-01
. Modulationwise, the dual inverter can be controlled using a carefully designed carrier-based pulsewidth-modulation (PWM) scheme that will always ensure balanced voltage boosting of the Z-source network while simultaneously achieving reduced common-mode switching. Because of the omission of dead-time delays...... in the dual-inverter PWM scheme, its switched common-mode voltage can be completely eliminated, unlike in traditional inverters, where narrow common-mode spikes are still generated. Under semiconductor failure conditions, the presented PWM schemes can easily be modified to allow the inverter to operate......This paper presents the design of a dual Z-source inverter that can be used with either a single dc source or two isolated dc sources. Unlike traditional inverters, the integration of a properly designed Z-source network and semiconductor switches to the proposed dual inverter allows buck...
DEFF Research Database (Denmark)
Mira Albert, Maria del Carmen; Zhang, Zhe; Knott, Arnold
2015-01-01
DC microgrids or nanogrids have attracted increasing research interest in recent years. Therefore, as a critical component, dc-dc converters with multiple inputs are required. In this paper, a dual-input interleaved buck/boost converter is proposed and its corresponding power flow control methods...
Current control of 6-phases 100kW interleaved buck/boost converter for railway application
2009-01-01
The purpose of this paper is to present a 6-phases interleaved buck-boost converter of 100kW de-signed for a hybrid locomotive. The IGBT’s are working partially in continuous and discontinuous con-duction mode. Experiments show the effectiveness of the digital current control, current sharing and discontinuous-continuous transition with only one current sensor
Funabiki, Shigeyuki; Yamamoto, Masayoshi
Renewable energy such as wind force and solar light has collected the attention as alternative energy sources of fossil fuel. An energy storage system with an electric double-layer capacitor (EDLC), which balances the demand and supply power, is required in order to introduce the electric power generating system that utilizes renewable energy. Currently, the research and development of these energy storage systems are actively carried out. In the energy storage system with an EDLC, the DC/DC converter having the function of the bidirectional power flow and the buck/boost performance is essential as an interface and power control circuit. There are two types of the bidirectional buck/boost DC/DC converters. One type consists of two buck/boost DC/DC converters with one reactor. The other type consists of two sets of two-quadrant DC/DC converters with one reactor. This paper discusses the comparison of these types of DC/DC converters with bidirectional power flow and buck/boost performance. The two types of DC/DC converters are estimated for their application to the energy storage system with the EDLC. As the voltage endurance of the device is lower and the mean current is smaller in the latter type of converter despite of having twice the number of devices compared to the former, the latter type of converter has the advantage of a smaller reactor, i.e., core volume and loss, and lower loss in the converter.
DEFF Research Database (Denmark)
Panfilov, Dmitry; Husev, Oleksandr; Blaabjerg, Frede;
2016-01-01
This study compares a three-phase three-level voltage source inverter with an intermediate dc-dc boost converter and a quasi-Z-source inverter in terms of passive elements values and dimensions, semiconductor stresses, and overall efficiency. A comparative analysis was conducted with relative...... parameters to evaluate converter parameters for any application. The equations obtained were confirmed by simulation and experimental setup. Field of application has been discussed....
Design of Three-Phase Three-Level CIC T-Source Inverter with Maximum Boost Control
DEFF Research Database (Denmark)
Shults, Tatiana; Husev, Oleksandr; Roncero-Clemente, Carlos
2015-01-01
This paper presents guidelines for component design of the three-level three-phase T-source inverter with continuous input current under maximum boost control proposed recently. Steady state analysis under low-frequency current and voltage ripples in the dc side was made. Component sizes for both...
DEFF Research Database (Denmark)
Ma, Ke; Blaabjerg, Frede
2016-01-01
This letter investigates the loss and thermal behaviors of a three-level neutral-point-clamped (3L-NPC) inverter undergoing moderate modulation index, which is typically presented during minor voltage sags of the power grid or speed changes of the electric machines. A series of new space vector m...
A New Zero Voltage Switching Buck-Boost Type DC-DC Converter
Directory of Open Access Journals (Sweden)
Majid Delshad
2010-03-01
Full Text Available In this paper, a new zero voltage switching isolated buck-boost DC-DC converter with active clamp circuit is proposed. The active clamp circuit in this converter not only absorbs voltage spikes across the main switch but also provides soft switching conditions for all switches. All switches are PWM controlled which simplifies the control implementation. One of the main advantages of this converter is the that it operating can operate at high power levels while soft switching conditions exist in both buck and boost modes of converter operation. Since this converter can operate over a wide input voltage range, it can be employed in power factor correction. The experimental results obtained from a 150W prototype circuit operating at 100KHz are presented to confirm the integrity of the proposed circuit.
Stability Analysis of the Buck-Boost Type Solar Array Regulator
Yang, Jeong-Hwan; Yoon, Seok-Teak; Park, Hee-Sung; Park, Sung-Woo; Koo, Ja-Chun; Jang, Jin-Baek; Lee, Sang-Kon
2014-08-01
The SAR (Solar Array Regulator) is different from a general DC-DC Converter. The input of the SAR is connected to the solar array and the output is connected to the battery. So, the output voltage of the SAR is constant and the input voltage of the SAR is variable. And the solar array current which is the SAR input current is variable according to the solar array voltage. Therefore, the SAR is influenced by the electrical characteristic of the solar array. For these reasons, a small signal model for a general DC-DC converter cannot be applied to the SAR for the stability analysis. In this paper, the small signal model of the BUCK-BOOST type SAR (BBSAR) is introduced and its transfer functions are induced. Using small signal transfer functions, the stability analysis is performed and its results are compared to the simulation result.
DEFF Research Database (Denmark)
Maheshwari, Ram Krishan; Munk-Nielsen, Stig; Busquets-Monge, S.
2013-01-01
A Neutral-Point-Clamped (NPC) three-level inverter with small dc-link capacitors is presented in this paper. The inverter requires zero average neutral-point current for stable neutral-point voltage. The small dc-link capacitors may not maintain capacitor voltage balance, even with zero neutral-point...... current. This may happen due to nonlinearities present in the circuit. This requires a fast control of the neutral-point voltage. A simple carrier based modulation strategy which allows modeling of the neutral-point voltage dynamics as a continuous function of power drawn from the inverter is proposed....... This continuous model shows that the neutral-point current is proportional to the power drawn from the inverter, and it enables the use of well established classical control theory for the neutral-point voltage controller design. A simple PI (proportional integral) controller is designed for the neutral-point...
Diagnosis and Tolerant Strategy of an Open-Switch Fault for T-type Three-Level Inverter Systems
DEFF Research Database (Denmark)
Choi, Uimin; Lee, Kyo Beum; Blaabjerg, Frede
2014-01-01
-tolerant strategy is explained by dividing into two cases: the faulty condition of half-bridge switches and the neutral-point switches. The performance of the T-type inverter system improves considerably by the proposed fault tolerant algorithm when a switch fails. The roposed method does not require additional......This paper proposes a new diagnosis method of an open-switch fault and fault-tolerant control strategy for T-type three-level inverter systems. The location of faulty switch can be identified by the average of normalized phase current and the change of the neutral-point voltage. The proposed fault...
Carrier-Based Common Mode Voltage Control Techniques in Three-Level Diode-Clamped Inverter
Directory of Open Access Journals (Sweden)
Pradyumn Chaturvedi
2012-01-01
Full Text Available Switching converters are used in electric drive applications to produce variable voltage, variable frequency supply which generates harmful large dv/dt and high-frequency common mode voltages (CMV. Multilevel inverters generate lower CMV as compared to conventional two-level inverters. This paper presents simple carrier-based technique to control the common mode voltages in multilevel inverters using different structures of sine-triangle comparison method such as phase disposition (PD, phase opposition disposition (POD by adding common mode voltage offset signal to actual reference voltage signal. This paper also presented the method to optimize the magnitude of this offset signal to reduce CMV and total harmonic distortion in inverter output voltage. The presented techniques give comparable performance as obtained in complex space vector-based control strategy, in terms of number of commutations, magnitude, and rate of change of CMV and harmonic profile of inverter output voltage. Simulation and experimental results presented confirm the effectiveness of the proposed techniques to control the common mode voltages.
Novel Family of modified qZS buck-boost multilevel inverters with reduced switch count
DEFF Research Database (Denmark)
Husev, Oleksandr; Strzelecki, Ryszard; Blaabjerg, Frede
2015-01-01
of levels with all possible sequences: reduced THD, reduced voltage stress on the transistors and size of the output filter. Also their modulation techniques are proposed and described. Simulation results have confirmed all theoretical predictions. The pros and cons are discussed in the conclusions....
Institute of Scientific and Technical Information of China (English)
Bao Bo-Cheng; Xu Jian-Ping; Liu Zhong
2009-01-01
By establishing the discrete iterative mapping model of a current mode controlled buck-boost converter, this paper studies the mechanism of mode shift and stability control of the buck-boost converter operating in discontinuous conduction mode with a ramp compensation current. With the bifurcation diagram, Lyapunov exponent spectrum, timedomain waveform and parameter space map, the performance of the buck-boost converter circuit utilizing a compensating ramp current has been analysed. The obtained results indicate that the system trajectory is weakly chaotic and strongly intermittent under discontinuous conduction mode. By using ramp compensation, the buck-boost converter can shift from discontinuous conduction mode to continuous conduction mode, and effectively operates in the stable period-one region.
Bao, Bo-Cheng; Xu, Jian-Ping; Liu, Zhong
2009-11-01
By establishing the discrete iterative mapping model of a current mode controlled buck-boost converter, this paper studies the mechanism of mode shift and stability control of the buck-boost converter operating in discontinuous conduction mode with a ramp compensation current. With the bifurcation diagram, Lyapunov exponent spectrum, time-domain waveform and parameter space map, the performance of the buck-boost converter circuit utilizing a compensating ramp current has been analysed. The obtained results indicate that the system trajectory is weakly chaotic and strongly intermittent under discontinuous conduction mode. By using ramp compensation, the buck-boost converter can shift from discontinuous conduction mode to continuous conduction mode, and effectively operates in the stable period-one region.
DEFF Research Database (Denmark)
Anthon, Alexander; Zhang, Zhe; Andersen, Michael A. E.
2016-01-01
. The first solution directly replaces the 1200 V primary Si IGBT switches with lower loss 1200 V SiC MOSFETs. The second solution strategically adds 600 V CoolMos FET devices to the conventional Si T-Type inverter to reduce the primary commutation losses. Semiconductor loss models, experimentally verified...
DEFF Research Database (Denmark)
Anthon, Alexander; Zhang, Zhe; Andersen, Michael A. E.
2016-01-01
. The first solution directly replaces the 1200V primary Si IGBT switches with lower loss 1200V SiC MOSFETs. The second solution strategically adds 600V CoolMos FET devices to the conventional Si T-Type inverter to reduce the primary commutation losses. Semiconductor loss models, experimentally verified...
Institute of Scientific and Technical Information of China (English)
Yang Ning-Ning; Liu Chong-Xin; Wu Chao-Jun
2012-01-01
In this paper,the fractional-order mathematical model and the fractional-order state-space averaging model of the Buck-Boost converter in continuous conduction mode (CCM) are established based on the fractional calculus and the Adomian decomposition method.Some dynamical properties of the current-mode controlled fractional-order BuckBoost converter are analysed.The simulation is accomplished by using SIMULINK.Numerical simulations are presented to verify the analytical results and we find that bifurcation points will be moved backward as α and β vary.At the same time,the simulation results show that the converter goes through different routes to chaos.
Directory of Open Access Journals (Sweden)
Ningning Yang
2016-01-01
Full Text Available In recent days, fractional calculus (FC has been accepted as a novel modeling tool that can extend the descriptive power of the traditional calculus. Fractional-order descriptiveness can increase the flexibility and degrees of freedom of the model by means of fractional parameters. Based on the fact that real capacitors and inductors are “intrinsic” fractional order, fractional calculus is introduced into the modeling process to establish a fractional-order state-space averaging model of the Buck-Boost converter in pseudo-continuous conduction mode (PCCM. Orders of the model are considered as extra parameters, and these parameters have significant influences on the performance of the model. The inductor current, the inductor current ripple, the amplitude of the output voltage, and the transfer functions of the fractional-order model are all related to orders. The contrast simulation experiments are conducted to investigate the performance of integer-order and fractional-order Buck-Boost converters in PCCM. Results of numerical and circuit simulations demonstrate that the proposed theoretical analysis is effective; the fractional-order model of the Buck-Boost converter in PCCM has certain theoretical and practical significance for modeling and performance analysis of other electrical or electronic equipment.
A Tapped-Inductor Buck-Boost Converter for a Dielectric ElectroActive Polymer Generator
DEFF Research Database (Denmark)
Dimopoulos, Emmanouil; Munk-Nielsen, Stig
2014-01-01
Energy harvesting applications based on Dielectric ElectroActive Polymer (DEAP) generators have been in the spotlight in recent years after the latter ones’ documented advantages against competing electromagnetic and field-activated technologies. Yet, the need for bidirectional energy flow under ...... energy harvesting of 0.42 J, at 0.75 Hz and 60 % delta-strain, characterized by a world-first; energy density equal to 2 J per kg of active material.......Energy harvesting applications based on Dielectric ElectroActive Polymer (DEAP) generators have been in the spotlight in recent years after the latter ones’ documented advantages against competing electromagnetic and field-activated technologies. Yet, the need for bidirectional energy flow under...... of commercially-available, high-efficient, high-voltage, low-power semiconductor devices. In this paper, a high-efficient bidirectional tapped-inductor buck-boost converter, addressing high step-up and high step-down voltage conversion ratios, is proposed for energy harvesting applications based on DEAP...
Buck-Boost/Forward Hybrid Converter for PV Energy Conversion Applications
Directory of Open Access Journals (Sweden)
Sheng-Yu Tseng
2014-01-01
Full Text Available This paper presents a charger and LED lighting (discharger hybrid system with a PV array as its power source for electronic sign indicator applications. The charger adopts buck-boost converter which is operated in constant current mode to charge lead-acid battery and with the perturb and observe method to extract maximum power of PV arrays. Their control algorithms are implemented by microcontroller. Moreover, forward converter with active clamp circuit is operated in voltage regulation condition to drive LED for electronic sign applications. To simplify the circuit structure of the proposed hybrid converter, switches of two converters are integrated with the switch integration technique. With this approach, the proposed hybrid converter has several merits, which are less component counts, lighter weight, smaller size, and higher conversion efficiency. Finally, a prototype of LED driving system under output voltage of 10 V and output power of 20 W has been implemented to verify its feasibility. It is suitable for the electronic sign indicator applications.
A New Transformerless Single-Phase Buck-Boost AC Voltage Regulator
Directory of Open Access Journals (Sweden)
YALCIN, F.
2016-05-01
Full Text Available Voltage regulation is one of the important goals for electrical sources and consumers. In this paper a new transformerless single-phase AC voltage regulator based on buck-boost converter topology is presented. The regulator circuit has a simple structure using only two bidirectional active switches, one inductor and one capacitor. A closed loop control system is implemented for the proposed regulator operation. A control law depending on the instantaneous values of the regulator's real input and desired output voltage is obtained and supports the PI controller. The control law allows the controller to obtain efficient pulse width modulation (PWM switching duty ratio for the desired output voltage when the input voltage has surges or fluctuations and the output load is changed. An experimental laboratory setup has been implemented for the proposed AC voltage regulator. The obtained results demonstrate that the proposed topology is capable of and efficient for both bucking and boosting the input AC voltage to a high quality output voltage with a low total harmonic distortion (THD for different input voltage and load conditions.
Start Up Current Control of Buck-Boost Convertor-Fed Serial DC Motor
Directory of Open Access Journals (Sweden)
Yusuf SÖNMEZ
2009-02-01
Full Text Available Generally, DC motors are given preference for industrial applications such as electric locomotives, cranes, goods lifts. Because of they have high starting moment; they initially start with high current. This high start-up current must be decreased since it may damage windings of the motor and increases power consumption. It could be controlled by an appropriate driver system and controller. The nature of fuzzy logic control has adaptive characteristics that can achieve robust response to a system with uncertainty, parameter variation, and load disturbance. In this paper, fuzzy logic based control of start-up current of a Buck-Boost Converter fed serial DC motor is examined through computer simulation. In order to see the advantages of fuzzy logic control, classical PI control has applied to the same motor, under same circumstances and has been compared. C++ Builder software has been used for the simulation. According to the simulation results, plainly, fuzzy logic control has stronger responses than classical PI control and uses lower current at starting moment.
Birchenough, Arthur G.
2003-01-01
Improvements in the efficiency and size of DC-DC converters have resulted from advances in components, primarily semiconductors, and improved topologies. One topology, which has shown very high potential in limited applications, is the Series Connected Boost Unit (SCBU), wherein a small DC-DC converter output is connected in series with the input bus to provide an output voltage equal to or greater than the input voltage. Since the DC-DC converter switches only a fraction of the power throughput, the overall system efficiency is very high. But this technique is limited to applications where the output is always greater than the input. The Series Connected Buck Boost Regulator (SCBBR) concept extends partial power processing technique used in the SCBU to operation when the desired output voltage is higher or lower than the input voltage, and the implementation described can even operate as a conventional buck converter to operate at very low output to input voltage ratios. This paper describes the operation and performance of an SCBBR configured as a bus voltage regulator providing 50 percent voltage regulation range, bus switching, and overload limiting, operating above 98 percent efficiency. The technique does not provide input-output isolation.
Institute of Scientific and Technical Information of China (English)
Jie ZHANG; Ryuichi YOKOYAMA; Jinhua SHE; Win WU
2013-01-01
One problem with a single source three-level inverter is the drafting of its neutral-point voltage. This may occur during transition or when unbalanced loads are connected to the inverter system. Variation of neutral-point voltage may greatly deteriorate the power quality. In this paper, we employ an equivalent-input-disturbance approach to deal with this problem. By adding an extra neutral leg, the control problem of neutral-point voltage is converted to a disturbance rejection problem. This method suppresses the variation of the neutral-point voltage to a low level and reduces the capacity of DC-link capacitors. Simulation results show the effectiveness of the method.
DEFF Research Database (Denmark)
Loh, Poh Chiang; Duan, Na; Liang, Chao;
2007-01-01
can only either perform voltage-buck or boost operation with buck-boost operation usually attained by adding additional actively controlled dc-dc converters. Although effective, the adding of dc-dc converters introduces additional active switches, which somehow dilute advantages associated...... with a reduced component count topology. Proposing alternative configurations with a reduced active semiconductor count, this paper discusses the systematic design of a number of Z-source B4 inverters, whose buck-boost capability is attained passively by inserting LC elements and clamping diodes. Visually...
Analysis and carrier-based modulation of Z-source NPC inverters
Dehghan, Seyed Mohammad; Mohamadian, Mustafa; Gharekhani, Reza
2012-08-01
Multi-level neutral-point-clamped (NPC) inverters are widely used in high and medium voltage applications. However, these inverters are only buck-type converters. Recently z-source NPC inverters have been proposed as the buck-boost three-level inverter. New inverters use a z-source network as the input stage. This article analyses the features and limitations of two main topologies of z-source NPC inverters (dual z-source network NPC inverter and single z-source network NPC inverter). The low-frequency ripple of the inductor current and the capacitor voltage of the z-source networks in the z-source NPC inverters are surveyed. This article also proposes two novel PWM methods for the z-source NPC inverters, which can be easily implemented experimentally. In the proposed methods, generated switching signals for the conventional NPC inverter are modified for the z-source NPC inverter using a simple logic circuit considering the boost factors and the power sharing ratio. The performance of the proposed simple PWM methods is verified by simulation and experimental results.
Institute of Scientific and Technical Information of China (English)
SONG Wen-xiang; YAO Gang; CHEN Chen; CHEN Guo-cheng
2008-01-01
A new modulation approach was presented for the control of neutral-point (NP) voltage variation in the three-level NP-clamped voltage source inverter, and the average NP current model was established based on vector diagram partition. Thus, theory base was built for balancing control of NP potential. Theoretical analysis and experimental results indicate that the proposed method for NP balancing control vector synthesizing concept based can make the average NP current zero, and do not influence NP potential within every sample period. The effectiveness of proposed research approach was verified by simulative and experimental results.
DEFF Research Database (Denmark)
Choi, Uimin; Lee, June-Seok; Lee, Kyo-Beum
2014-01-01
and medium switching states are employed to help the neutral-point voltage balancing. This method little bit increases the switching events and output total harmonic distortion. However, this method has a strong balancing ability at all regions. Further, it is very simple to implement in both space vector......This paper proposes a new modulation strategy that balances the neutral-point voltage for three-level neutral-clamped inverter systems. The proposed modulation replaces the P-type or N-type small switching states with other switching states that do not affect the neutral-point voltage. The zero...
DEFF Research Database (Denmark)
Lee, Kyo-Beum; Huh, Sung-Hoe; Yoo, Ji-Yoon;
2005-01-01
A stable sensorless controller for DTC of induction motor fed by three-level inverter using the Radial Basis Function Network (RBFN) is presented in this paper. The torque ripple can be drastically reduced and low speed performance can be obtained in the DTC system for high performance induction...... motor drives. However, speed control performance is still influenced by the lumped uncertainties of the system such as parameter variations, external load disturbances, and unmodeled dynamics which make it difficult to obtain an exact mathematical model. In this paper, the lumped uncertainties...
DEFF Research Database (Denmark)
Maheshwari, Ram Krishan; Munk-Nielsen, Stig; Busquets-Monge, S.
2012-01-01
The size of passive components in an adjustable speed drive can be reduced by using small dc-link capacitors. The EMI filter in the drive also consists of passive components. The size of the filter can be reduced by using a three-level inverter, which can have low output voltage distortion. However......, the three-level inverter based on small dc-link capacitors requires a PWM strategy to maintain neutral-point voltage balance. In this paper, the common mode voltage, which is the determining factor for the EMI filter size, is analyzed for a virtual-vector-based PWM strategy. The common mode voltage....... Results show that the conducted emission from the three-level inverter is lower than that of the two-level inverter. Thus, a three-level inverter requires a smaller EMI filter in motor drives with small dc-link capacitors....
Institute of Scientific and Technical Information of China (English)
马化盛; 张波; 郑健超; 梁少毅
2004-01-01
以AC/DC Buck-Boost PFC变换器为主拓扑,提出滑模变结构电流内环控制与PI调节器电压外环控制相结合的综合控制系统,以实现变换器高性能的单位功率因数校正.仿真和实验研究结果表明,这种控制系统设计兼有滑模控制动态性能、鲁棒性好与PI调节器稳定性好的优点.
2015-01-01
In this paper, a design and control for the buck-boost converter, i.e., 1-plus-D converter with a positive output voltage, is presented, which combines the 1-plus-D converter and the synchronous rectified (SR) buck converter. By doing so, the problem in voltage bucking of the 1-plus-D converter can be solved, thereby increasing the application capability of the 1-plus-D converter. Since such a converter operates in continuous conduction mode inherently, it possesses the nonpulsating output cu...
Directory of Open Access Journals (Sweden)
Muhammad Taufiq Ramadhan
2015-03-01
Full Text Available Penggunaan mobil listrik secara umum terkendala pada beban, kecepatan aktual, serta efisiensi energi. Pemanfaatan Fuzzy Logic Controller untuk pengaturan kecepatan motor DC pada mobil listrik diperlukan untuk meraih kecepatan aktual yang lebih presisi sehingga diperoleh efisiensi energi. Selain itu perlu juga menggunakan Bidirectional Buck-Boost Cascade Converter untuk pengaturan motor DC secara bidirectional, yakni pengaturan saat motoring dan saat pengereman regeneratif (regenerative braking. Hal ini berdasar pada energi yang terbuang percuma, baik itu rugi elektris maupun rugi mekanis saat pengereman.
DEFF Research Database (Denmark)
Maheshwari, Ram Krishan; Munk-Nielsen, Stig; Busquets-Monge, S.
2012-01-01
In a voltage source inverter, overmodulation is required to extend the range of operation and enhance the dc-link voltage utilization. A carrier-based implementation of a modulation strategy for the three-level neutral-point-clamped inverter is proposed for the overmodulation region. The modulati...
Institute of Scientific and Technical Information of China (English)
修瑞仙; 张士宇
2015-01-01
This paper introduced the working state of single switch quadratic Buck-Boost converter in continuous-discontinuous conduction mode, researched the photovoltaic cells model and maximum power tracking theory,through the simulation analysis,obtained the quadratic CDCM Buck-Boost converter applied to photovoltaic power generation system could realize the maximum power point tracking and wide range maximum power tracking,and was not affected by load change.%介绍了单开关二次型Buck-Boost变换器在连续—断续导电模式下的工作状态，研究了光伏电池模型及最大功率跟踪原理，通过仿真分析，得出将二次型CDCM Buck-Boost变换器应用到光伏发电系统中可实现最大功率点跟踪与宽范围的最大功率跟踪，并且不受负载变化影响。
Li, Peng; Zhang, Chongxiao; Kim, Junyoung; Yu, Liangyao; Zuo, Lei
2014-04-01
Regenerative semi-active suspensions can capture the previously dissipated vibration energy and convert it to usable electrical energy for powering on-board electronic devices, while achieve both the better ride comfort and improved road handling performance at the same time when certain control is applied. To achieve this objective, the power electronics interface circuit connecting the energy harvester and the electrical loads, which can perform simultaneous vibration control and energy harvesting function is in need. This paper utilized a buck-boost converter for simultaneous semi-active vibration control and energy harvesting with electromagnetic regenerative shock absorber, which utilizes a rotational generator to converter the vibration energy to electricity. It has been found that when the circuit works in discontinuous current mode (DCM), the ratio between the input voltage and current is only related to the duty cycle of the switch pulse width modulation signal. Using this property, the buck-boost converter can be used to perform semi-active vibration control by controlling the load connected between the terminals of the generator in the electromagnetic shock absorber. While performing the vibration control, the circuit always draw current from the shock absorber and the suspension remain dissipative, and the shock absorber takes no additional energy to perform the vibration control. The working principle and dynamics of the circuit has been analyzed and simulations were performed to validate the concept.
Directory of Open Access Journals (Sweden)
Yap Hoon
2016-07-01
Full Text Available A new control technique known as inverted error deviation (IED control is incorporated into the main DC-link capacitor voltage regulation algorithm of a three-level neutral-point diode clamped (NPC inverter-based shunt active power filter (SAPF to enhance its performance in overall DC-link voltage regulation so as to improve its harmonics mitigation performances. In the SAPF controller, DC-link capacitor voltage regulation algorithms with either the proportional-integral (PI or fuzzy logic control (FLC technique have played a significant role in maintaining a constant DC-link voltage across the DC-link capacitors. However, both techniques are mostly operated based on a direct voltage error manipulation approach which is insufficient to address the severe DC-link voltage deviation that occurs during dynamic-state conditions. As a result, the conventional algorithms perform poorly with large overshoot, undershoot, and slow response time. Therefore, the IED control technique is proposed to precisely address the DC-link voltage deviation. To validate effectiveness and feasibility of the proposed algorithm, simulation work in MATLAB-Simulink and experimental implementation utilizing a TMS320F28335 Digital Signal Processor (DSP are performed. Moreover, conventional algorithms with PI and FLC techniques are tested too for comparison purposes. Both simulation and experimental results are presented, confirming the improvement achieved by the proposed algorithm in terms of accuracy and dynamic response in comparison to the conventional algorithms.
Institute of Scientific and Technical Information of China (English)
孙孝峰; 仇江峰; 栗晓华; 骆志伟
2016-01-01
研究一种集成Buck-Boost LLC(integrated Buck-Boost LLC，IBBLLC)变换器。该变换器适用于宽输入电压范围场合的应用，通过开关管的共用变换器减少了开关管数量。通过采用PWM+Phase-Shift控制，使得原边各个开关管在全输入电压和全负载范围内均能够实现零电压开通(zero voltage switching，ZVS)。文中首先介绍变换器的拓扑结构及直流增益。其次详细分析变换器的工作模式及前级电感Lb对变换器性能的影响，为变换器参数的选取提供了理论依据。此外，研究变换器的ZVS特性，给出变换器能够实现 ZVS 的工作区域。最后搭建一台200~450 V 输入、14 V/80 A 输出的实验样机，实验结果验证了理论分析的正确性及方案的可行性。%An integrated Buck-Boost LLC (IBBLLC) converter which is a good candidate for wide input voltage applications was researched. By sharing the switches, the amount of the switches is reduced. In order to make all primary switches realize ZVS under whole input voltage range and load conditions, PWM+Phase-Shift control strategy is employed in this converter. Firstly, the topology and DC gain of the converter was introduced. Then the operations modes and the influence of inductor was introduced which can provide theoretical foundation for the parameters selection. Besides, the ZVS conditions were analyzed and the ZVS operation area of the converter was given. Finally, a prototype with 200~450V input voltage, 14V output voltage and 80A output current was established to verify the correctness of the theoretical analysis and the feasibility of the control strategy.
A tapped-inductor buck-boost converter for a multi-DEAP generator energy harvesting system
DEFF Research Database (Denmark)
Dimopoulos, Emmanouil; Munk-Nielsen, Stig
2014-01-01
the effective operational range of the power electronic converter. In this paper, a bidirectional tapped-inductor buck-boost converter is proposed, addressing high-efficient high step-up and high step-down voltage conversion ratios, for energy harvesting applications based on DEAP generators. The effective...... operational range of the converter is extended, by replacing its high-side switch with a string of three serialized MOSFETs, to accommodate the need for high-efficient high-voltage operation. Experiments conducted on a single DEAP generator - part of a quadruple DEAP generator energy harvesting system...... with all elements installed sequentially in the same circular disk with a 90 phase shift - validate the applicability of the proposed converter, demonstrating energy harvesting of 0.26 J, at 0.5 Hz and 60 % delta-strain; characterized by an energy density of 1.25 J per kg of active material....
Li, Qing; Zhang, Xiao-ping; Chen, Qi
2011-12-01
The dynamic performance of a novel Buck-Boost matrix converter (BBMC) based on double-loop control strategy is put forward in this paper. The fundamental principle of BBMC has been elaborated and the method of the double-loop control strategy has been built with Matlab, and then the dynamic performances of BBMC based on the double-loop control strategy are discussed. The results show that the output voltage and frequency can be almost constant with the BBMC and double-loop control strategy despite of the changeable input voltage and frequency. Moreover, a high-quality sine output wave with low harmonic distortion can be directly obtained without filtering. So it can be drawn that the BBMC based on the double-loop control strategy has perfectly dynamic performance and practical importance to the engineering.
Directory of Open Access Journals (Sweden)
Shi-Zhou Xu
2015-01-01
Full Text Available The high-power three-level explosion-proof inverters demand high thermal stability of power devices, and a set of theories and methods is needed to achieve an accurate power-loss calculation of power devices, to establish heat dissipation model, and ultimately to reduce the power loss to improve thermal stability of system. In this paper, the principle of neutral point clamped three-level (NPC3L inverter is elaborated firstly, and a fourth-order RC equivalent circuit of IGBT is derived, on which basis the power-loss model of IGBT and the optimized maternal power-loss thermal model, using an optimized power-loss algorithm, are established. Secondly, in accordance with the optimized maternal power-loss thermal model, the generic formulas of power-loss calculation are deduced to calculate the power-loss modification values of NPC3L and soft switching three-level (S3L inverters, which will be the thermal sources during thermal analysis for maternal power-loss thermal models. Finally, the experiment conducted on the 2.1 MW experimental platform shows that S3L inverter has the same excellent output characteristics with NPC3L inverter, reduces the power loss significantly by 213 W in each half-bridge, and decreases the temperature by 10°C, coinciding with the theoretical calculation, which verifies the accuracy of optimized power-loss algorithm and the effectiveness of the improvement.
Institute of Scientific and Technical Information of China (English)
赵犇; 马瑞卿
2015-01-01
An additional DC?DC converter is needed for traditional boost power factor correction ( PFC) converter to obtain low output voltage. When using buck type topology, the distortion of input current is large because no pow?er is transferred to output when gird voltage is lower than output voltage. Thus, the buck?boost type topology be?comes priority in the low output voltage application. Compared with the classic cascaded buck?boost PFC converter, the proposed single stage bridgeless buck?boost topology has lower semiconductors counts, and lower devices counts in the conduction loop which means less conduction losses. The tapped inductor is employed to achieve more attenu?ation. Thus, the proposed topology suits the low output voltage application very well. The One Cycle Control ( OCC) is adopted to achieve good dynamic performance and the elimination of multiplier can simplify the control circuit and reduce the cost. The simulated results and their analysis show preliminarily that:(1) the proposed topology is feasible and has the merits of simple structure and less conduction losses; ( 2 ) the power factor correction using OCC is reliable and has the advantages of low current distortion and high power factor.%传统的boost型功率因数校正变换器需要额外1级DC?DC变换器才能实现低电压输出,而buck型拓扑由于在电网电压低于输出电压时没有输入电流而导致电流畸变很大,因此buck?boost型拓扑就成为在低电压输出场合实现单级式功率因数校正的优先选择. 相较于经典的级联式buck?boost功率因数校正变换器,文中所提出的单级式无桥buck?boost拓扑所需的半导体器件数量更少,且导通回路中的功率器件个数也大大减小,从而可以降低导通损耗;加上引入了耦合电感提高了电压衰减率,因此特别适合低电压输出场合;采用了单周期控制作为功率因数校正的控制方法,具有更好的动态性能,而且电路实现中无需乘法
Institute of Scientific and Technical Information of China (English)
张斐; 许建平; 杨平; 陈章勇
2012-01-01
A novel two-switch Buck-Boost power factor correction （PFC） converter operating in pseudo continuous conduction mode （PCCM） and its corresponding control strategy were proposed in this paper. The two-switch PCCM Buck-Boost PFC topology provides an additional degree of control freedom to realize PFC control, which can offer significant performance improvements over single-switch Buck-Boost PFC converters or two-switch Buck-Boost PFC converters in continuous conduction mode （CCM） and discontinuous conduction mode （DCM）. The additional degree of control freedom introduced by inductor current freewheeling stage helps to achieve unity power factor control. Besides, inductor current ripple of the two-switch PCCM Buck-Boost PFC converter, which is lower than that of the two-switch DCM Buck-Boost PFC converter, can be obtained. Analysis, simulation and experiment results of the two-switch PCCM Buck-Boost PFC converter were presented. The experiment results show that the dynamic response of the two-switch PCCM Buck-Boost PFC converter is significantly faster than that of the two-switch CCM and DCM Buck-Boost PFC converter.%提出两开关伪连续导电模式（pseudocontinuousconductionmode，PCCM）Buck-Boost功率因数校jE（powerfactorcorrection，PFC）变换器及其控制策略。利用两开关PCCMBuck．BoostPFC变换器电感惯性模态所提供的一个额外控制自由度，可实现单位功率因数控制，并明显改善传统单开关Buck-BoostPFC变换器、两开关连续导电模式（continuousconductionmode，CCM）Buck．BoostPFC变换器和两开关不连续导电模式（discontinuousconductionmode，DCM）Buck-BoostPFC变换器的性能。与两开关DCMBuck．BoostPFC变换器相比，两开关PCCMBuck．BoostPFC变换器减小了电感电流纹波。仿真与实验结果表明，两开关PCCMBuck-BoostPFC变换器的负载动态响应速度明显快于传统的两开关CCM和DCMBuck-BoostPFC变换器。
Institute of Scientific and Technical Information of China (English)
张斐; 许建平; 董政; 舒立三
2013-01-01
研究了两开关伪连续导电模式(pseudo continuous conduction mode,PCCM) Buck-Boost功率因数校正(power factor correction,PFC)变换器的工作原理,为了简化两开关PCCM Buck-Boost PFC变换器的控制器设计,在分析单相PFC变换器输出电压纹波的基础上,提出了输出电压纹波反馈控制算法.该算法采样PFC变换器的输出电压,通过计算得到输出电压纹波值来实时调整电流控制环的补偿系数,无需增加额外的硬件电路,利用数字信号处理器的编程方式即可实现.仿真与实验结果表明,当负载功率发生大范围变化时所设计的系统具有快速动态响应能力.
Diagnosis method of an open-switch fault for a grid-connected T-type three-level inverter system
DEFF Research Database (Denmark)
Choi, U. M.; Lee, K. B.; Blaabjerg, Frede
2012-01-01
This paper proposes a diagnosis method of an open-switch fault and fault-tolerant control algorithm for a grid-connected T-type three-level inverter. The location of the faulty switch is identified by using the changes of average phase current and the neutral-point voltage. The fault-tolerant con......This paper proposes a diagnosis method of an open-switch fault and fault-tolerant control algorithm for a grid-connected T-type three-level inverter. The location of the faulty switch is identified by using the changes of average phase current and the neutral-point voltage. The fault......-tolerant control algorithm can be used when the open switch fault occurs in the middle switches. It is achieved by simply modifying the conventional SVM method. The proposed methods are advantageous as they do not require additional sensors and they do not involve complex calculations. Therefore, this method...
Chebabhi, Ali; Fellah, Mohammed Karim; Kessal, Abdelhalim; Benkhoris, Mohamed F
2016-07-01
In this paper is proposed a new balancing three-level three dimensional space vector modulation (B3L-3DSVM) strategy which uses a redundant voltage vectors to realize precise control and high-performance for a three phase three-level four-leg neutral point clamped (NPC) inverter based Shunt Active Power Filter (SAPF) for eliminate the source currents harmonics, reduce the magnitude of neutral wire current (eliminate the zero-sequence current produced by single-phase nonlinear loads), and to compensate the reactive power in the three-phase four-wire electrical networks. This strategy is proposed in order to gate switching pulses generation, dc bus voltage capacitors balancing (conserve equal voltage of the two dc bus capacitors), and to switching frequency reduced and fixed of inverter switches in same times. A Nonlinear Back Stepping Controllers (NBSC) are used for regulated the dc bus voltage capacitors and the SAPF injected currents to robustness, stabilizing the system and to improve the response and to eliminate the overshoot and undershoot of traditional PI (Proportional-Integral). Conventional three-level three dimensional space vector modulation (C3L-3DSVM) and B3L-3DSVM are calculated and compared in terms of error between the two dc bus voltage capacitors, SAPF output voltages and THDv, THDi of source currents, magnitude of source neutral wire current, and the reactive power compensation under unbalanced single phase nonlinear loads. The success, robustness, and the effectiveness of the proposed control strategies are demonstrated through simulation using Sim Power Systems and S-Function of MATLAB/SIMULINK.
Directory of Open Access Journals (Sweden)
Jeevan Naik
2015-06-01
Full Text Available In this paper, a design and control for the buck-boost converter, i.e., 1-plus-D converter with a positive output voltage, is presented, which combines the 1-plus-D converter and the synchronous rectified (SR buck converter. By doing so, the problem in voltage bucking of the 1-plus-D converter can be solved, thereby increasing the application capability of the 1-plus-D converter. Since such a converter operates in continuous conduction mode inherently, it possesses the nonpulsating output current, thereby not only decreasing the current stress on the output capacitor but also reducing the output voltage ripple. Above all, both the 1-plus-D converter and the SR buck converter, combined into a buck–boost converter with no right-half plane zero, use the same power switches, thereby causing the required circuit to be compact and the corresponding cost to be down. Furthermore, during the magnetization period, the input voltage of the 1-plus-D converter comes from the input voltage source, whereas during the demagnetization period, the input voltage of the 1-plus-D converter comes from the output voltage of the SR buck converter.
Demirbaş, Şevki; Fidanboy, Hikmet; Kurt, Erol
2016-08-01
In this paper, detailed analyses of the chaotic behavior observed in a buck-boost converter are presented. Although this basic converter system is already known world-wide for the purpose of dc-dc conversion of the output of renewable energy systems, it indicates certain chaotic regimes where both the output amplitude and frequency change randomly. This chaotic regime can yield an unstable output over the resistive or resistive/inductive electrical loads. This study presents a detailed map for the regular and chaotic regions in terms of material parameters, such as converter capacitance C, resistive load R, and inductive load L. Thus, the stable area of operation for efficient and renewable electricity production will be ascertained for the studied converter system. We emphasize that the material parameters C, R, and L play important roles in generating energy from the solar cell; indeed, the stability increases with higher values of the converter capacitor and load inductance, whereas it decreases according to the resistive load. A number of periodic windows have been observed and the output frequency gives a broad-band spectrum of up to 50 kHz.
A tapped-inductor buck-boost converter for a multi-DEAP generator energy harvesting system
Dimopoulos, Emmanouil; Munk-Nielsen, Stig
2014-03-01
Interest on Dielectric ElectroActive Polymer (DEAP) generators has aroused among scientists in recent years, due to the former ones' documented advantages against competing electromagnetic and field-activated technologies. Yet, the need for bidirectional energy flow under high step-up and high step-down voltage conversion ratios, accompanied by low-average but relatively high-peak currents, imposes great challenges on the design of the employed power electronic converter. On top of that, the shortage of commercially-available, high-efficient, high-voltage, low-power semiconductor devices limits the effective operational range of the power electronic converter. In this paper, a bidirectional tapped-inductor buck-boost converter is proposed, addressing high- efficient high step-up and high step-down voltage conversion ratios, for energy harvesting applications based on DEAP generators. The effective operational range of the converter is extended, by replacing its high-side switch with a string of three serialized MOSFETs, to accommodate the need for high-efficient high-voltage operation. Experiments conducted on a single DEAP generator - part of a quadruple DEAP generator energy harvesting system with all elements installed sequentially in the same circular disk with a 90° phase shift - validate the applicability of the proposed converter, demonstrating energy harvesting of 0.26 J, at 0.5 Hz and 60% delta- strain; characterized by an energy density of 1.25 J per kg of active material.
Uno, Masatoshi; Tanaka, Koji
Series connections of energy-storage modules such as electric double-layer capacitors (EDLCs) and lithium-ion batteries result in voltage imbalance because of the nonuniform properties of individual modules. Conventional voltage equalizers based on traditional dc-dc converters require numerous switches and/or transformers, and therefore, their costs and complexity tend to increase. This paper proposes a novel single-switch equalization charger using multiple stacked buck-boost converters. The single-switch operation not only reduces the circuit complexity but also contributes to increasing the reliability. The fundamental operating principles and design procedures of key components are presented in detail. An experimental charge test using a 25W prototype of the proposed equalization charger was performed for four series-connected EDLC modules whose initial voltages were intentionally imbalanced. Experimental results demonstrated that the proposed equalization charger could charge the series-connected modules preferentially in the order of increasing module voltage and that all the modules could be charged up to a uniform voltage level.
Directory of Open Access Journals (Sweden)
Soumyadeep Ray
2014-07-01
Full Text Available This article proposes a newly proposed highly effective Zero Voltage and Zero Current switching based Front end converter with a High Frequency Transformer with a Three Phase Three Level Diode Clamped Inverter in photovoltaic applications. The switching scheme is implemented in MATLAB/ Simulink condition. ZVZCS condition is achieved. This type of converter shows high efficiency and very negligible switching loss. Finally ZVZCS based High Frequency Link Diode Clamped Inverter is connected to Grid. An MCI optimized Current controller is used with SVM switching technique. In This article, responses with three types of controllers (I, PI, PID have been examined and compared. Simulation results show the effectiveness, and validity of this technique.
基于模糊PI的buck-boost变换器控制%Fuzzy PI Control for Buck-boost Converter
Institute of Scientific and Technical Information of China (English)
王磊
2012-01-01
For the strong nonlinearity of the DC/DC converter, this paper proposes a new fuzzy PI con⁃troller, which combines fuzzy control method with traditional PI dual loop control method. All the details about the fuzzy PI controller are provided, including the key structure, working principle, design process and parame⁃ter tuning method. The overall software and hardware solutions for the controller are designed where TMS320F240 DSP is the control core device. Then as an example, a simulation of buck-boost converter under given parameters is run to verify the close loop behavior of the controller. Simulation results show that the new fuzzy PI controller may greatly enhance the static and dynamic performance of the converter system.% 针对DC/DC变换器的强非线性，提出了一种新的模糊PI控制器，将模糊控制方法与传统线性PI的电压、电流双环控制方法结合形成闭环系统。给出了模糊PI控制器的结构原理、设计过程和参数整定方法，并对给定参数的buck-boost变换器作为实例进行了仿真验证，同时以TMS320F2812DSP为核心控制器件，设计了系统整体实现的软硬件方案。仿真结果表明，新的模糊PI控制器能够较大地提升系统的动、静态性能。
Yang, Fengping; Xiao, Fangfei
2017-03-01
Current control methods include hardware control and software control corresponding to the inherent unbalance problem of neutral point voltage in three level NPC inverter. The hardware control is rarely used due to its high cost. In this paper, a new compound control method has been presented based on the vector method of virtual space and traditional hysteresis control of neutral point voltage, which can make up the shortcoming of the virtual control without the feedback control system of neutral point voltage and the blind area of hysteresis control and control the deviation and wave of neutral point voltage. The accuracy of this method has been demonstrated by simulation.
Directory of Open Access Journals (Sweden)
Benlafkih Abdessamad
2013-01-01
Full Text Available this paper presents comparative performance between Analog and digital controller on DC/DC buck-boost converter four switch. The design of power electronic converter circuit with the use of closed loop scheme needs modeling and then simulating the converter using the modeled equations. This can easily be done with the help of state equations and MATLAB/SIMULINK as a tool for simulation of those state equations. DC/DC Buckboost converter in this study is operated in buck (step-down and boost (step-up modes.
Institute of Scientific and Technical Information of China (English)
吴捷; 刘明建; 杨苹
2002-01-01
This paper studies the bifurcation and chaos in current-mode controlled Buck-Boost converter. The discrete model for Buck-Boost converter in continuous conduction mode (CCM) is derived. The bifurcation and chaos phenomena of Buck-Boost converter have been investigated with input voltage E, reference current Iref, resistor R, inductor L and capacitor C as bifurcation parameters.%研究了电流控制型Buck-Boost变换器中的分叉与混沌问题.首先,对连续模式下的Buck-Boost变换器建立了离散数学模型,在此基础上,在输入电压E、参考电流Iref、电阻R、电感L和电容C等分叉参数作用下,通过数值方法对Buck-Boost变换器中的分叉与混沌进行了详细的仿真研究.仿真研究结果表明:Buck-Boost变换器具有丰富的非线性行为--分叉与混沌,随着各个分叉参数的变化系统会遵循倍周期分叉的规律走向混沌.
Directory of Open Access Journals (Sweden)
Bharati Raja
2012-12-01
Full Text Available This work presents the comparative study of the different PWM techniques to reduce the common-mode voltage (CMV at the output of neutral point diode clamped inverter for variable speed drives. Here the comparative study is done by the phase opposition disposed (POD, sinusoidal pulse width modulation (SPWM, phase disposition (PD, phase shift (PS space vector modulation (SVM techniques are proposed. A good trade-off between the quality of the output voltage and the partial magnitude of the CMV is achieved in this work. The scheme is proposed for three-level inverter. This work realizes the implementation of Three-level diode clamped MLI for three-phase (Y-Δ induction motor with the implementation of a space vector modulation technique without any additional control algorithm to reduce CMV within the range + Vdc/6. The Simulation with a 1HP induction motor drive system is setup in Matlab-2011b and the same results validated effectively by hardware – FPGA-SPARTEN III processor and its shows that the CM voltage is effectively reduced and the maximum output voltage is not affected.
Institute of Scientific and Technical Information of China (English)
殷立; 王顺强
2012-01-01
The inner intrinsic safety of BUCK-BOOST convert is analyzed by minimum ignition curve. The worst-case energy of BUCK-BOOST is calculated. Comparing with the minimum ignition curve, the intrinsic safety of BUCK-BOOST convert is implemented. Through calculation, the maximum load capacitor and inductance are obtained.%从最小点燃曲线角度分析BUCK-BOOST变换器内部本质安全性能,推算出BUCK-BOOST最恶劣情况下的能量,与火花点燃曲线相比较,得到本安输出的BUCK-BOOST变换器,并通过计算得出最大负载电容及负载电感。
Energy Technology Data Exchange (ETDEWEB)
Widyan, M.S.
2010-07-01
Photovoltaic (PV) cells for powering direct current (DC) motors are designed to provide maximum output power at the rated conditions of the motors. This paper presented the dynamic and steady-state characteristics of DC shunt, series and permanent-magnet motors fed by PV cells via a DC-DC buck-boost (step up-step down) switch mode converter. It considered the nonlinearities of the output characteristics of the PV cells and that of the magnetization curve of the machines. In order to address the problem of voltage regulation of the PV cells and the variation in solar illumination, the duty cycle controls the output voltage of the DC-DC converter to maintain a fixed voltage across the terminals of the motors at any realistic loading conditions. In this study, the DC-DC buck-boost switch mode converter achieved a fixed voltage across the terminals of the motors and therefore good speed regulation under a wide range of loading conditions and solar intensities. The entire study was carried out using the Matrix Laboratory Program MATLAB{sup TM} software.
Computer Simulation Based Study of a Buck-Boost Circuit%基于计算机仿真的Buck-Boost电路研究
Institute of Scientific and Technical Information of China (English)
王利清; 魏学业; 温伟刚
2004-01-01
Buck-Boost电路中含有丰富的非线性现象.它工作过程中电路拓扑结构的循环切换导致了谐波、分叉和混沌等非线性行为.基于PSPICE仿真,研究了电流控制DC/DC Buck-Boost开关转换器中的倍周期现象.而且,建立了开关转换器的数学模型和叠代映射来解释这种非线性现象.基于MATLAB仿真,从叠代映射中得到了系统分叉图.%A buck-boost circuit is rich in nonlinear dynamics. Its operation is characterized by cyclic switching of circuit topologies, which gives rise to a variety of nonlinear, such as subharmonics, bifurcation and chaos. Based on PSPICE, the period-doubling phenomena exhibited by a current-programmed DC/DC buck-boost switching converter are studied. Furthermore, the system model and the iterative map of the converter are derived to explain the nonlinear phenomena. Based on MATLAB, the numerical simulation with this iterative map has led to the bifurcation diagram.
Paulkovich, J.; Rodriguez, G. E. (Inventor)
1981-01-01
A voltage regulated DC to DC converter uses an inductor and a capacitor as storage elements. The inductor is composed of two windings having a common junction. A transformer with a center tap connected to the common junction of the two windings is connected at either end of its winding to ground through controlled switches. One winding of the inductor and either end of the transformer winding are connected by power diodes to the capacitor which supplies the output voltage to a load. The other winding of the inductor is connected to a fourth power diode as a clamping diode. Input voltage is supplied to the inductor through a third controlled switch. A pulse width modulator connected to the output of the converter alternately closes and opens the switches connected to either end of the transformer winding and also closes the switch supplying input voltage to the inductor each time either of the switches connected to the ends of the transformer winding are closed. The duty cycle of the closing and opening of the several switches is adjusted by the pulse modulator to regulate the output voltage.
Dead-time Effects and Compensation of Three-level Inverters%三电平逆变器中的死区效应与补偿
Institute of Scientific and Technical Information of China (English)
杨兵建; 杨波; 何湘宁; 邓焰
2011-01-01
Based on the analysis of the dead-time effects on the fundamental and low order harmonic components of the neutral point clamped three-level inverter output voltage, a pulse based dead-time compensation method applied to the neutral point clamped three-level inverter is presented.The output currents are detected at every starting and middie of the carrier wave cycle respectively and the PWM pulses are adjusted according to the polarity of the output currents to make the actual pulse time identical to the ideal pulse time, so that the dead-time effect can be well compensated.This method significantly reduces the output distortion and regains the output RMS value.The experimental results are given to demonstrate the validity of this method.%分析了二极管箱位型三电平逆变器的死区效应对输出电压基波和低次谐波的影响,提出了适用于二极管箝位型三电平逆变器的死区补偿方法.该方法分别在载波的开始和中间采样输出电流,根据检测到的输出电流方向调整功率器件的开关动作时刻,最终使得输出电压波形与理论波形一致,达到良好的补偿效果.该方法能有效减小输出谐波含量,并恢复由死区效应引起的有效值损失.最后通过实验证实了该方法的有效性.
Modeling and design of DCM Buck-Boost converter%DCM Buck-Boost变换器的建模与控制设计
Institute of Scientific and Technical Information of China (English)
方露; 党幼云; 康朋飞
2015-01-01
DC converter has the characteristics of nonlinear and multi modal .The model building of Buck-Boost converter is the key to design its closed-loop control system. The reliable output voltage and perfect dynamic characteristic of the Buck-Boost converter was greatly influenced by it. The AC small signal model is build on the basis of Buck-Boost converter's average switch model. Then get the transfer function of system. The voltage loop was also designed based on it. The design details for voltage loop were given and zero-pole compensation method from classic control theory was applied to the field of power electronics. The design of closed-loop control system and the model were verified through the analysis of the result of simulation in MATLAB software.%直流变换器一般具有非线性、多模态等特点。 Buck-Boost变换器的建模是其闭环控制设计的关键，对于Buck-Boost变换器输出可靠的电压和良好的动态响应特性具有非常重要的影响。本文是在Buck-Boost变换器断续模式的平均开关模型基础上建立其小信号交流模型，并推导出系统传递函数。在此基础上设计了电压闭环控制系统，进行了电压闭环参数设计的研究，实现了控制理论中零极点补偿法在电力电子中的应用。利用MATLAB软件进行仿真分析，验证了模型和闭环控制设计的正确性。
Modelling and Control Design of a Dual Buck-Boost AC/DC Converter Used in the DC Nano-Grid
DEFF Research Database (Denmark)
Wu, Weimin; Liu, Yuan; Wang, Houqing;
2016-01-01
like the low voltage AC power system. In this paper, a dual Buck-Boost AC/DC converter for use in the united grounding configuration based DC Nano-grid with three terminal outputs is proposed. It will be much easy to construct an efficient DC Nano-grid based on the existing low AC power system by using......Due to widely used DC characterized loads and more distributed power generation sources, the DC Nano-grid becomes more and more popular and seen as an alternative to the AC-grid in future. For the safety considerations, the DC Nano-grid should provide reliable grounding for the residential loads...... the proposed converter. The working principle of this converter and the system modeling are presented in detail. Simulations are carried out to verify the theoretical analysis....
Directory of Open Access Journals (Sweden)
Faqiang Wang
2011-01-01
Full Text Available The influence of switching frequency on the low-frequency oscillation in the voltage-controlled buck-boost converter is studied in this paper. Firstly, the mathematical model of this system is derived. And then, a glimpse at the influence of switching frequency on the low-frequency oscillation in this system by MATLAB/Simulink is given. The improved averaged model of the system is established, and the corresponding theoretical analysis is presented. It is found that the switching frequency has an important influence on the low-frequency oscillation in the system, that is, the low-frequency oscillation is easy to occur when the switching frequency is low. Finally, the effectiveness of the improved averaged model and the theoretical analysis are confirmed by circuit experiment.
Institute of Scientific and Technical Information of China (English)
谢莉; 蒋伟
2015-01-01
本文研究了储能设备的均衡充电方法。采用垂直 Buck-Boost 电路作为均衡器的基本交换单元。在不同的负载条件下，用状态空间平均法和小信号分析法获得对应的开关单元模型。通过电压控制均衡方案，利用电压环补偿设备端电压，电流内环使得电荷定向移动。实验结果表明，所提出的均衡器能实现电荷最快移动并能有效地收敛到零电压差，本地控制器能快速、准确地跟踪参考值。%This paper investigates the active charge equalization method for energy storage devices. The vertical buck-boost circuit is used as the basic switching cell of this equalizer. By applying state-space averaging and small signal analysis, the model of the switching cell is obtained under different load condition. A voltage controlled equalization scheme is presented, which is featured with voltage loop to equalize the terminal voltage and inner current loop for charge shuttling. The simulation and experimental results indicate that the proposed equalizer can effectively converge to zero voltage difference condition by offering a maximized charge shuttling effort, and the local controller can react fast and precisely to the reference command.
Institute of Scientific and Technical Information of China (English)
吴捷; 刘明建; 杨苹
2002-01-01
研究了电流控制型Buck-Boost变换器中的分叉与混沌问题.在连续模式下的Buck-Boost变换器的离散数学模型基础上,从不动点及稳定性理论的角度对Buck-Boost变换器的第一分叉点进行了严格的数值分析,得到了三维参数空间曲面图.此外,建立了实验硬件电路,实验结果验证了理论分析.%The first flip bifurcation point of Buck-Boost converter has been studied in detail by using fixed point and stability theory. 3-D parameter space of stable region is given. Furthermore, the hardware of 20kHz current-moxe controlled BuckBoost converter has been built and the experiment results verify the theoretical analysis which has been presented in our other papers.
Institute of Scientific and Technical Information of China (English)
张伦健; 卢春艳; 陈利萍
2013-01-01
研究了一种具有升降压能力的中点箝位型(NPC)三电平Z源逆变器(ZSI),给出三电平ZSI拓扑结构,并分析其工作原理.基于传统三电平逆变器的空间矢量调制原理,设计了一种不需要死区延时的三电平ZSI空间矢量调制法,通过对两个阻抗网络进行选择性直通控制,使三电平ZSI对直流输入电压进行升压的同时,不会产生额外的器件换流.基于Matlab/Simulink搭建仿真模型对所设计的空间矢量调制法进行仿真分析,仿真结果表明所设计的调制法具有有效性.%A neutral-point-clamped (NPC) three level Z source inverter with both voltage-buck and voltage-boost capabilities was studied in this paper.The topologic of three level Z source inverter was provided,and its basic principle was analyzed.Based on space vector modulation algorithm of conventional three level inverter,an appropriate pulse width modulation (PWM) algorithm with no requirement for deadtime delay was designed for three level Z source inverter by short circuiting two impendence network selectively,it made the Z source inverter have the minimal device commutations per switching cycle when ZSI boosted the voltage.In order to verify the designed SVPWM algorithm,the simulation model of three level Z source inverter was built.The simulation results demonstrate that the designed SVPWM algorithm was valid.
Novel, Four-Switch, Z-Source Three-Phase Inverter
DEFF Research Database (Denmark)
Antal, Robert; Muntean, Nicolae; Boldea, Ion
2010-01-01
) value as in six switch standard three-phase inverter. The article presents the derivation of the equations describing the operation of the converter based on space vector analysis, validation through digital simulations in PSIM and preliminary experimental results on a laboratory setup with a dsPIC30F......, besides the self-boost property, has low switch count and it can operate as a buck-boost inverter. In contrast to standard four-switch three-phase inverter which operates at half dc input voltage the proposed four-switch z-source inverter, by self boosting, brings the output voltage at same (or higher...
Institute of Scientific and Technical Information of China (English)
刘文江; 张晓军; 王旭光
2006-01-01
提出和设计了一种新型BUCK-BOOST AC-AC变换电路,详细阐述了其结构和工作原理.该电路采用ARM嵌入式处理器和先进的控制策略,实现了全数字控制.实验结果表明,该电路具有很好的调压效果.
George, Libin; Gargiulo, Gaetano Dario; Lehmann, Torsten; Hamilton, Tara Julia
2016-06-01
This paper presents the design of a reconfigurable buck-boost switched-capacitor DC-DC converter suitable for use in a wide range of biomedical implants. The proposed converter has an extremely small footprint and uses a novel control method that allows coarse and fine control of the output voltage. The converter uses adaptive gain control, discrete frequency scaling and pulse-skipping schemes to regulate the power delivered to a range of output voltages and loads. Adaptive gain control is used to implement variable switching gain ratios from a reconfigurable power stage and thereby make coarse steps in output voltage. A discrete frequency scaling controller makes discrete changes in switching frequency to vary the power delivered to the load and perform fine tuning when the output voltage is within 10% of the target output voltage. The control architecture is predominately digital and it has been implemented as part of a fully-integrated switched-capacitor converter design using a standard bulk CMOS 0.18 μm process. Measured results show that the converter has an output voltage range of 1.0 to 2.2 V, can deliver up to 7.5 mW of load power and efficiency up to 75% using an active area of only 0.04 mm (2), which is significantly smaller than that of other designs. This low-area, low-complexity reconfigurable power converter can support low-power circuits in biomedical implant applications.
Nine Level Inverter with Boost Converter from Renewable Energy Source
Directory of Open Access Journals (Sweden)
Maruthu Pandiyan.R
2015-01-01
Full Text Available A new single phase nine level multilevel inverter is proposed. The input to the proposed nine level multilevel inverter is obtained from solar panel . The solar energy obtained from the solar panel is not constant and it varies with times. In order to maintain the constant voltage obtained from the solar panel the boost converter is used to maintain the constant output voltage using MPPT ( Perturb and observe algorithm algorithm. Then the buck boost converter output voltage is stored in the battery bank. Finally the battery energy is connected to the 9 level inverter circuits. The harmonics in the inverter is eliminated by using the fuzzy logic controller. The gate pulse for the multilevel inverter is given by the fuzzy logic controller which in turn reduces the harmonics in the inverter. Then the inverter output is connected to the grid are some application.
Magnetically Coupled Impedance-Source Inverters
DEFF Research Database (Denmark)
Loh, Poh Chiang; Blaabjerg, Frede
2013-01-01
input-to-output gain and the presence of an impedance network. The former means a high dc-link voltage, which can stress the semiconductor switches unnecessarily. The latter leads to increases in cost and size, which similarly are undesirable. To lessen these concerns, an interesting approach is to use......Z-source inverters are a new class of inverters proposed with output voltage or current buck-boost ability. Despite their general attractiveness, there are some present limitations faced by existing Z-source inverters, most of which are linked to their requirement for low modulation ratio at high...... magnetically coupled transformers or inductors to raise the gain and modulation ratio simultaneously, while reducing the number of passive components needed. A study of the approach is now presented to show how various existing magnetically coupled inverters can be derived by applying a generic methodology...
Magnetically coupled impedance-source inverters
DEFF Research Database (Denmark)
Loh, Poh Chiang; Blaabjerg, Frede
2012-01-01
input-to-output gain, and the presence of an impedance network. The former means a high dc-link voltage, which can stress the semiconductor switches unnecessarily. The latter leads to increases in cost and size, which similarly are undesirable. To lessen these concerns, an interesting approach is to use......Z-source inverters are a new class of inverters proposed with output voltage or current buck-boost ability. Despite their general attractiveness, there are some present limitations faced by existing Z-source inverters. Most of which are linked to their requirement for low modulation ratio at high...... magnetically coupled transformers or inductors to raise the gain and modulation ratio simultaneously, while reducing the number of passive components needed. A study of the approach is now presented to show how various existing magnetically coupled inverters can be derived by applying a generic methodology...
DEFF Research Database (Denmark)
Ma, Ke; Blaabjerg, Frede
2012-01-01
investigates the loss and thermal performances of a 10 MW 3L-NPC wind power inverter undergoing Low Voltage Ride Through (LVRT) operation. A series of new space vector modulation methods are then proposed to relocate the thermal loading among the power switching devices. It is concluded that, with the proposed...
Energy Technology Data Exchange (ETDEWEB)
Erdman, W.; Keller, J.; Grider, D.; VanBrunt, E.
2014-11-01
A high-efficiency, 2.3-MW, medium-voltage, three-level inverter utilizing 4.5-kV Si/SiC (silicon carbide) hybrid modules for wind energy applications is discussed. The inverter addresses recent trends in siting the inverter within the base of multimegawatt turbine towers. A simplified split, three-layer laminated bus structure that maintains low parasitic inductances is introduced along with a low-voltage, high-current test method for determining these inductances. Feed-thru bushings, edge fill methods, and other design features of the laminated bus structure provide voltage isolation that is consistent with the 10.4-kV module isolation levels. Inverter efficiency improvement is a result of the (essential) elimination of the reverse recovery charge present in 4.5-kV Si PIN diodes, which can produce a significant reduction in diode turn-off losses as well as insulated-gate bipolar transistor (IGBT) turn-on losses. The hybrid modules are supplied in industry-standard 140 mm x 130 mm and 190 mm x 130 mm packages to demonstrate direct module substitution into existing inverter designs. A focus on laminated bus/capacitor-bank/module subassembly level switching performance is presented.
NPC型三电平逆变器供电的永磁同步电机矢量控制系统%PMSM vector control system by NPC three-level inverter-fed
Institute of Scientific and Technical Information of China (English)
谢剑云; 徐华勒
2014-01-01
Because three -level neutral point clamped ( NPC ) inverter has less distorted output , good control performance and other advantages , a new vector control method for the permanent magnet synchronous motor ( PMSM) based on a three-level NPC inverter is presented .Firstly, the three-level NPC inverter space voltage vector pulse width modulation ( SVPWM ) technique is analyzed in detail . Then, this NPC inverter is applied in PMSM vector control .Finally, a simulation experiment of the pro-posed control algorithm is carried out .The simulation results show the proposed method can effectively suppress the torque ripple and improve driving performance for the PMSM driver system .%在分析永磁同步电机矢量控制理论的基础上，结合三电平中点钳位（ NPC）逆变器输出谐波含量低、控制性能好等优点，提出了一种基于NPC型三电平逆变器的永磁同步电机（ PMSM ）矢量控制方法。深入分析了三电平逆变器空间电压矢量脉宽调制（ SVPWM ）技术，并利用Matlab/Simulink进行了基于三电平逆变器SVPWM算法的PMSM矢量控制仿真实验，结果表明三电平逆变器SVPWM和PMSM矢量控制的有机结合，有效地抑制了转矩脉动，提高了驱动性能。
Research on Three-phase and Three-level PV's Inverter Based on SVPWM%基于SVPWM的三相三电平光伏并网逆变器的研究
Institute of Scientific and Technical Information of China (English)
张雪; 曹勇; 胡艳美; 邢峰华
2015-01-01
For two-stage grid-connected inverter of photovoltaic system, the controlling method of a three-phase and three-level inverter was introduced based on voltage space vector, so it can achieve a lower switching frequency, weaken the waveform distortion of line current in the AC side, and improve power factor in the AC side. The structure of a three-phase and three-level photovoltaic grid inverter was designed and the system incremental method was used to achieve maximum power tracking; The grid inverter control mode selects SVPWM. In addition, this paper sets up the simulation model through Matlab/Simulink to verify the feasibility system and improve the power quality of grid inverter.%针对两级式光伏发电系统的并网逆变器，提出基于电压空间矢量作为三相三电平逆变器的控制方式，实现了降低开关频率，减弱了交流侧线电流的波形畸变，提高交流侧的功率因数。设计了三相三电平光伏并网逆变器系统的结构，采用导纳增量法实现最大功率跟踪，并网逆变器的控制方式选用 SVPWM ，并通过Matlab/Simulink搭建仿真模型，验证了系统可行性，改善了并网逆变器的电能质量。
Institute of Scientific and Technical Information of China (English)
刘悦新; 王磊
2016-01-01
非隔离型交错并联双向Buck/Boost变换器普遍存在轻载效率低的难题。以多相交错并联Buck/Boost变换器Boost模式为研究对象，分别对其工作在DCM和CCM模式下的功率损耗进行综合性分析研究。根据变换器轻载运行时降低频率可以提高效率的原则，提出最优化调频原则，对其不同负载下开关频率进行调整，以达到提高效率的目的。针对降低频率会带来纹波恶化的缺陷，将磁集成技术应用到交错并联双向Buck/Boost变换器，有效改善通道电感电流纹波及输出电压纹波，并给出磁集成后滤波电容优化设计原则，以最大程度减小损耗，提高轻载效率。最后通过仿真和实验验证了理论分析的正确性，为交错并联双向Buck/Boost 变换器轻载效率优化提供了新的理论依据，推动了全负载高效率双向Buck/Boost变换器的设计实现。%The non-isolated interleaving bi-directional Buck-Boost converter is faced with a widespread problem of low underloading efficiency. The Boost model of the multi-phase interleaving Buck/Boost converter is adopted as the research object in this paper, and a comprehensive analysis of power loss is conducted under the DCM and CCM model. According to the principle that efficiency can be increased through reduced frequency during underloading operation of the transformer, and the principle of optimized frequency modulation is put forward to adjust the switching frequency under different loads so as to realize the goal of increasing efficiency. Concerning the defect of worsening ripples caused by reduced frequency, the magnetic integration technique is applied to the interleaving bi-directional Buck/Boost converter to efficiently improve the channel’s inductive current ripples and the output voltage ripples. Besides, the filter capacitor optimized design principle after magnetic integration is given at an attempt to minimize loss and increase underloading
Institute of Scientific and Technical Information of China (English)
王菲; 王勇; 傅旻帆
2014-01-01
三电平逆变器因为电压应力只有两电平逆变器的一半，并且具有损耗小、谐波含量低的特点，所以在风能、太阳能等新能源发电系统中得到了越来越多的应用和研究。文中从新能源的功率随机波动特点出发，首先，评估了应用于新能源系统的传统三电平逆变器拓扑的损耗特点，然后，针对应用于光伏发电系统的三电平并网逆变器提出了硬件和控制策略上的改进，最后，利用一台样机验证了所提出的改进措施。试验证明，所提改进措施能够有效改善和提高三电平逆变器的效率，尤其是在中低功率范围内的效率。%By virtue of its remarkably low voltage stress,low harmonics and low power loss,the three-level inverter is increasingly applied in renewable energy systems such as the solar and wind power system.Anyway,the manifest feature of the new energy generating system is power fluctuation.Proceeding from the stochastic power fluctuation,the conventional three-level inverter is evaluated in terms of its topological power loss first.Then,some new schemes of hardware and control strategies are proposed for a three-level inverter applied in a solar inverter. Finally, a prototype is built to verify the improvement.Test results show the proposed schemes can improve the efficiency of the three-level inverter,especially the efficiency in the low and medium power range.
Institute of Scientific and Technical Information of China (English)
王学梅; 易根云; 丘东元; 张波
2012-01-01
针对现有＂电力电子技术＂教材中普遍存在的对Buck-Boost变换器的分析不完整等问题,本文基于伏秒平衡原理对Buck-Boost变换器进行了全面分析,推导出变换器全范围的输入输出电压关系,电流连续模式（CCM）和断续模式（DCM）的临界工作条件以及电路各参数对电流纹波和电压纹波的影响等。本文一方面有助于更全面深入地理解Buck-Boost变换器的工作原理及特性,另一方面有助于DC-DC变换器分析方法的统一,具有一定的教学指导意义。%There are some incomplete analyses of buck-boost converters in current materials of power electronics. Based on the principle of volt-second balance, this paper analyzes the buck-boost converter comprehensively. Next, the ratio of input and output voltage in full range is derived, and the critical working conditions in continuous conduction mode and discontinuous conduction mode are analyzed. Last, the effects of circuit parameters on current and voltage rip- ple are illustrated. On the one hand, this paper can help to understand thoroughly the operating principle of buck-boost converter, and on the other hand, it also can help to analyses DC-DC converters uniformly, which has certain signifi- cance in the teachings of power electronics.
Institute of Scientific and Technical Information of China (English)
李萍; 刘国忠
2012-01-01
二极管箝位型(NPC)三电平逆变器在中、高压大容量功率变换装置中的需求越来越迫切,目前已成为研究的热点.讨论利用功率开关所生成的不同电压矢量优化合成旋转参考空间电压矢量及各矢量作用时间分配的方案,实现SVPWM控制策略驱动逆变器；讨论实时改变控制负小矢量作用时间的系数以平衡直流侧母线中点电位的问题.仿真结果验证了NPC三电平逆变器SVPWM控制策略的正确性及中点电位平衡控制的有效性.%Diode NPC (neutral -point -clamped) three-level inverter is increasingly and urgently needed for medium to high-voltage and large-capacity power conversion devices, and becomes a research hot spot at present. Three voltage vectors generated by power switches are used to optimally synthesize space rotary reference voltage victors by assigned action time to each voltage vector to realize SVPWM inverter. Meanwhile, the DC neutral -point voltage of inverter is balanced thorough real-time adjusting action time of small negative vectors. The simulation results validate that the SVPWM scheme is correct for controlling NPC three -level inverter and the balance of neural-point voltage is effective.
Institute of Scientific and Technical Information of China (English)
赵犇; 马瑞卿
2015-01-01
单周期控制由于其动态响应好、抗干扰性强、控制电路实现简单,被广泛运用在传统Boost类PFC变换器中.针对一种新型的无桥Buck-Boost PFC变换器拓扑,研究了单周期控制与传统平均电流控制在该类型拓扑中的应用.通过原理分析,证明了在无桥类拓扑中单周期控制可以避免平均电流控制所必须采用的输入电压检测,其电路实现更容易,成本更低廉;同时,通过仿真验证了单周期控制比平均电流控制的动态响应更快.证明了在无桥Buck-Boost类PFC变换器中,单周期控制比平均电流控制更具优势,性价比更高.
Design of isolated Buck-Boost DC/DC converter%Buck-Boost隔离直流转换器设计
Institute of Scientific and Technical Information of China (English)
王雪丹; 李文鹤
2012-01-01
在Buck-Boost隔离直流转换器宽范围输入电压的条件下,分析了典型的全桥Boost转换器拓扑结构,由于存在的谐振电感包括漏电感,全桥Boost转换器只能采用双边沿调制.该转换器采用UC3895作为控制器,对全桥单元采用移相转换控制的方式,为了提高全桥Boost转换器系统的可靠性和效率,采用三模式两频率控制方式,在输入宽范围电压的情况下,最高500 V输入,360 V输出.在此采用Matlab软件进行仿真,实验结果表明输入电压平均效率范围是96.2％,最高效率能达到97.5％.%The topology structure of a typical FB Boost converter was analyzed under the condition of wide range input voltage of isolated Buck-Boost DC/DC converter. The FB Boost converter can only adopt two-edge-modulation (TEM) due to the resonant induction including the leakage induction. The converter takes UC3895 available in market as the controller to control the FB-cell with phase-shifted. In order to improve the reliability and efficiency of the FB-Boost converter, a three-mode dual-frequency control mode was used. The maximum input voltage is 500 V and the output'is 360 V in the case of the wide range input voltage. The Matlab software was adopted for simulation. The result shows the the average efficiency range of the input-voltage is 96. 2% and the highest efficiency can reach to 97. 3%.
基于不同调制方式的三电平逆变器仿真研究%Research and simulation of three-level inverter based on different modulations
Institute of Scientific and Technical Information of China (English)
牛海伟; 任永峰; 刘峰; 关勇; 丛雨
2013-01-01
首先讨论了三电平二极管中点箝位型PWM逆变器电路拓扑,其次分析了空间电压矢量脉宽调制(SVPWM)的基本原理,并在Matlab/simulink中对三电平逆变器进行了仿真,然后分析了载波相移调制(CPS-SPWM)技术的基本原理,并利用这种调制方式在PSIM仿真软件中对三电平逆变器进行了仿真,仿真结果证实了SVPWM算法和CPS-SPWM实现方法是正确可行的.%The circuit topology of the three-phase,three-level,and diode neutral-point-clamped PWM inverter was discussed,and the basic principle of the SVPWM was analyzed.The vector space was divided into six large areas,and each large one was divided into six small areas.The simulation model of the control system for the three-phase three-level PWM inverter was established in the Matlab simulation environment.The simulation results verify that the proposed vector PWM algorithm and realizing method are valid and feasible.
Institute of Scientific and Technical Information of China (English)
张佩炯
2011-01-01
空间矢量脉宽调制在多电平逆变器的控制中应用广泛,但是随着电平数增加,控制算法渐趋复杂化。提出了三电平空间矢量脉宽调制控制方法,将三电平电压矢量区变换为由两电平空间矢量区构成,从而通过使用两电平空间矢量脉宽调制方法简化了控制算法。该方法理论上可应用于更高电平逆变器的控制中,仿真验证了方法的可行性。%Space vector pulse width modulation is widely applied in control of multi-level inverters, but following increasing of level number, the control algorithm becomes more and more complicated. Three-level space vector pulse width modulation control method was raised to transfer three-level voltage vector zone to two-level space vector zones, so as to simplify the control algorithm with two-level space vector pulse modulation method. The method on the theory can be used to control much higher level inverters and simulation has verified feasibility of the method.
Institute of Scientific and Technical Information of China (English)
李文娟; 王超; 冯杰; 周美兰; 高晗璎
2016-01-01
Aiming at the problems of open-loop three-level inverter circuit poor stability,slow dynamic response,weak carrying capacity,the voltage-current double closed-loop control scheme is proposed.The diode-clamped three-level inverter circuit is regarded as the controlled object.The math model of inverter circuit on two-phase synchronous rotating coordinates is established.The designs of current loop and voltage loop are carried out respectively.The current loop includes the inductance current feed-forward decoupling based on dq axis and the design of corresponding PI parameters. Voltage loop includes the capacitance voltage feed-forward decoupling based on dq axis and the design of controller parameters.The simulation model of three-level inverter circuit with double closed-loop control is built in the Simulink simulation platform.The waveforms of the output voltage and current of the double closed-loop control under the condition mutation loads are analyzed.%针对开环的三电平逆变电路稳定性差、动态响应慢、带载能力弱等问题，提出了电压、电流双闭环的控制方案。选取二极管箝位式三电平逆变电路作为被控对象，建立其在同步旋转坐标系下的数学模型，分别对电流环和电压环进行设计。电流环包括基于 d 、q 轴的电感电流前馈解耦及 PI 参数的设计；电压环包括基于 d 、q 轴的电容电压前馈解耦及控制器参数的设计。在 Simulink 仿真实验平台上，建立了双闭环控制的三电平逆变电路的仿真模型，分析了突变负载情况下双闭环控制的逆变输出电压和电流的仿真波形。
Operational analysis and comparative evaluation of embedded Z-Source inverters
DEFF Research Database (Denmark)
Blaabjerg, Frede; Gao, F.; Loh, P.C.;
2008-01-01
This paper presents various embedded Z-source (EZ-source) inverters broadly classified as shunt or parallel embedded Z-source inverter. Being different from the traditional Z-source inverter, EZ-source inverters are constructed by inserting dc sources into the X-shaped impedance network so...... that the dc input current flows smoothly during the whole switching period unlike the traditional Z-source inverter. This feature is interesting when PV panels or fuel cells are assumed to power load since the continuous input current flow reduces control complexity of dc source and system design burden....... Carefully analyzing the operational principles for shoot-through and nonshoot-through switching, it is first revealed that the shunt-embedded Z-source inverters with capacitors partially or fully replaced by dc sources can appropriately perform buck-boost operation with rear-end current source inverter (CSI...
Institute of Scientific and Technical Information of China (English)
Manfred W. Gekeler
2013-01-01
The Soft Switching Three Level Inverter (S3L) was first presented in 2011. It represents a novel topology for pulse width modulation (PWM) inverters that are used in electrical drives, in grid supply inverters for photovoltaic and wind power plants and for power supplies. It has a rather simple structure and is thus economically priced. It is completely operated in soft switching mode and consequently only displays very low switching losses. As a result, the efficiency rate is very high and particularly high switching frequency values can be achieved. In the present paper, the functionality is described, prototypes with output power from 20 kVA to 90 kVA are presented and results are specified.% 软开关三电平逆变器(soft switching three-level inverter，S3L)于2011年首次推出。它代表了脉宽调制(pulse width modulation，PWM)逆变器的一种新的拓扑结构，应用于电力驱动，光伏和风力发电厂的并网逆变器，以及用于供电领域。因其结构非常简单，所以价格相当低廉。它完全在软切换模式下运行，并且持续表现出极低的切换损耗。其结果是，效率非常高，而且可以实现特别高的切换频率。该论文对其功能进行描述，还展示一部输出电源为20~90 kVA 的逆变器样品，并对测试结果作详细说明。
Institute of Scientific and Technical Information of China (English)
洪峰; 刘周成; 万运强; 尹培培; 赵鑫; 王成华
2014-01-01
漏电流降低了非隔离型并网逆变装置的安全性和可靠性。已有研究通过将双极性调制全桥逆变器或半桥逆变器三电平化解决该问题。提出基于三电平双Buck逆变器的新思路，并重点研究其中的三电平双Buck全桥电路。该拓扑是将双Buck半桥逆变器中的输入均压电容用一个工频开关的桥臂取代得到，使得对地寄生电容电压在半周期内保持不变，有效地抑制漏电流至几乎可以忽略的程度。同时，该拓扑保持了双Buck电路无桥臂直通、体二极管不工作等特点，又降低了器件电压应力，使得桥臂输出变为单极性调制波。通过与各种无漏电流结构的综合比较可知，该拓扑除在器件总量上比H5结构多一个功率管外，在有源器件数量、通态电流经过器件数量、高频开关器件数量、是否需要均压控制等方面，均有一定优势，有助于降低系统复杂度，提高可靠性与变换效率。仿真与实验验证了上述分析。%Leakage currents reduce the reliability and the security of non-isolated grid-connected inverters. Three-level topologies based on the dual-polarity modified full bridge inverter or the half bridge inverter were the existing methods to resolve this problem. The use of three-level topologies based on the dual buck inverter is a new way proposed by this paper. As the input divider capacitors of the dual buck half bridge inverter have been replaced by one working period switching bridge, a so-called three-level dual buck full bridge inverter is obtained. Because the voltage of stray capacitor remains unchanged in each half period, there is no leakage current. And there is no shoot-through problem, and none of the body-diodes in this topology needs to work. At the same time, the stresses of devices were reduced, and the outputs of bridge-legs become uni-polarity. The new topology was compared with no leakage current existed topologies. The total
Institute of Scientific and Technical Information of China (English)
孙孝峰; 刘飞龙; 熊亮亮; 王宝诚
2016-01-01
In this paper, Dual Buck/Boost integrated dual active bridge (DAB) three-port DC-DC converter combines the conventional DAB and two bidirectional Buck/Boost circuits. Hence power switches are shared, and the power density is improved. The PV-battery hybrid power system is taken as an example to analyze the proposed converter topology. The phase shift plus PWM control is adopted here. The phase shift angle is used to control the power flow between the input port and the output port, while the duty cycle is employed to match the input voltages. Thus the maximum power point tracking (MPPT) can be achieved and the power flow between PV and battery can be balanced. The basic operation principles, steady state characteristics and zero voltage switching (ZVS) conditions are analyzed. The ZVS conditions for the conventional DAB operating in small phase shift angle can be greatly improved, and thus the converter can operate under ZVS in a wide operation range. A 300 W converter prototype is built to verify all considerations.%在传统的双有源桥变换器的基础上集成两个双向 Buck/Boost 电路，提出了一种双Buck/Boost 集成双有源桥三端口 DC-DC 变换器，该变换器实现了桥臂开关管的复用，提高了功率密度。以光伏-蓄电池混合发电系统为例对该变换器拓扑进行分析，采用移相+PWM进行控制，通过控制移相角实现输入与输出端口间功率传输，通过调节占空比来匹配输入端口电压等级，以实现光伏端口的最大功率点跟踪和平衡蓄电池端口的能量传递。分析了该变换器的工作原理、稳态与软开关特性，该变换器较大程度地改善了传统移相控制下 DAB 在移相角较小时的软开关条件，使得在宽工作范围内能够实现所有功率开关管的软开关。最后建立300W实验样机进行方案验证。
A Novel Average Model for Unified Buck-Boost DC/DC Converter%一种新型的升-降压型直流变换器电路仿真平均模型
Institute of Scientific and Technical Information of China (English)
康婉莹; 沈淼森; 钱江; 钱照明
2001-01-01
提出了一种新型的单开关升-降压式(Buck-Boost)直流变换器的电路仿真平均模型.这种模型可通过输入参数的选择实现对Buck-Boost电路的电压控制、峰值及平均电流控制,以及对DCM-CCM工作方式的统一.它是一种实用的仿真模型,可方便地进行稳态和动态分析.在保证准确的基础上,大幅度提高了仿真的速度,通常比用实际器件开关电路的仿真速度提高两到三个数量级.
基于Buck-Boost变换器的T-S模糊建模和仿真研究%T-S fuzzy modeling and simulation of Buck-Boost converter
Institute of Scientific and Technical Information of China (English)
王艳; 吴正成; 纪志成
2008-01-01
根据Buck-Booat变换器的工作原理及其非线性特征,在电感电流连续导通模式和断续导通模式下,分别对Buck-Boost 电路构建T-S模糊模型,在断续导通模式下,引入切换函数,统一了两种模式下电路状态方程和T-S模糊模型.仿真结果表明,Buck-Boost变换器经T-S建模后,输出电压平均值和电感电流的平均值的误差均在2%以内,符合实际应用的要求.T-S模糊建模的有效性和可行性得到验证.
Institute of Scientific and Technical Information of China (English)
苟斌; 冯晓云
2011-01-01
With the development of high-express electric multiple units, the design and application of three-level inverter are more and more extensive.The traditional space vector pulse width modulation(SVPWM) method for the three-level inverter needs to estimate the sectors and calculate a lot of trigonometric functions. As a result,the calculating quantity of micro-processor is increased. Because the basic three-level space vector is a regular hexagon,the algorithm based on 60°coordinate system avoids a lot of trigonometric operations.The indirect field oriented control strategy is introduced. And a DSP-based induction motor control platform is built to verify the simple SVPWM algorithm. Experimental results show that the adopted method can omit a lot of trigonometric functions, and reduce the calculating burden of the control system.%随着高速动车组的发展,三电平逆变器的研究和应用越来越广泛,其传统的空间矢量脉宽调制(SVPWM)方法需要进行大量的三角函数运算及扇区判定,增大了控制器的计算工作量.由于α,β坐标系中,三电平基本空间矢量图为正六边形,基于60°坐标系下的SVPWM算法,在计算基本矢量作用时间时避免了大量的三角函数运算.采用间接磁场定向矢量控制策略,搭建了一个基于DSP的异步电机矢量控制平台来验证60°坐标系下SVPWM方法的可行性.实验结果表明,该方法在基本矢量作用时间的计算中避免了大量的三角函数运算,减少了控制系统计算时间.
Wind-Photovoltaic Hybrid Double-Input Buck-Boost DC/DC Converter%风光互补双输入Buck-Boost直流变换器的研究
Institute of Scientific and Technical Information of China (English)
廖志凌; 徐艳杰; 施卫东
2014-01-01
Instability and intermittency are two main drawbacks of independent solar energy generation. Therefore, it is essential to use a double-input DC/DC converter, which combines wind with solar to form a hybrid energy system. The paper proposes a new double-input Buck-Boost DC/DC converter with the following advantages: simple circuit, high voltage gain, and allowance of individual or simultaneous power delivery of the two sources. The operation principle of the double-input Buck-Boost DC/DC converter is analyzed, and the steady-state relation between convert input and output is presented. Finally, simulation results with PSPICE software are used to verify the theoretical analysis.%采用双输入直流变换器将太阳能和风能联合构成双输入供电系统，可避免独立光伏发电系统电力供应不稳定和不连续的缺点。本文提出一种新的双输入Buck-Boost直流变换器，具备电路结构简单、电压增益高特点，联合供电系统既可同时向负载供电，又可分体单独向负载供电。分析双输入Buck-Boost直流变换器的工作原理，给出变换器的输入/输出稳态关系式，并通过PSPICE软件进行仿真。仿真结果验证了理论分析的正确性。
Institute of Scientific and Technical Information of China (English)
郭思雯; 任家敏; 段迎娟; 王义; 马骥; 张斌; 王聪
2016-01-01
讨论了一种用于辅助电力电子技术理论教学的光伏发电系统实验演示装置的研制，重点分析了中点钳位三电平光伏逆变器的设计。该逆变电路通过SPWM控制方法，将直流电压转换成负载所需的交流电压，具有谐波少、效率高等一系列优点。基于光伏发电实验演示装置通过模块化的形式，将光伏发电的过程清晰地呈现出来，同时通过改变光伏板的倾斜程度可以完成各种演示实验，使理论教学过程更直观，更富有活力。%This paper discusses the development of an experimental demonstration device for the power electronic technology theory teaching, focusing on the design of the neutral point clamped three level photovoltaic inverter. The inverter circuit through the SPWM control method, the DC voltage is converted into the AC voltage required to load, with a series of advantages of low harmonic and high efifciency. Based on the discussion of photovoltaic power generation experimental demonstration device through the modular form, the process of photovoltaic power generation is clear, and the degree of tilt of the PV panels can be completed by various experiments, the theory teaching process is more intuitive, more dynamic.
Institute of Scientific and Technical Information of China (English)
周熙炜; 梅芳; 陈金平; 林海
2016-01-01
深入分析基本空间矢量SV与特定谐波消去SHEPWM之间的内在联系，提出三电平NPC逆变器的一种基于空间分区矢量提取的SHEPWM调制策略,推导出空间电压矢量PWM的三相等效调制波规则采样的开关角矩阵，得出基本空间矢量SV的选用与规则采样的运算关系以及SHEPWM的脉冲状态由基本SV组成的矢量序列特殊解。在此基础上，在三电平NPC逆变器的矢量空间六边形所分区的两电平六边形中，研究SHEPWM脉冲序列的空间电压矢量组成的扇区分布，并提取相应的基本SV，求解作用时间。 SHEPWM的脉冲状态由空间分区提取的基本SV矢量序列运算合成而实现，避开了其开关角非线性超越方程组的求解，并具有同样的消谐效果且便于实现。%According to the studies of internal relation for the basic space vector(SV) and the selective harmonic elimination PWM (SHEPWM), this paper puts forward a kind of SHEPWM implementation strategy based on the space partition vector SV extraction to the three-level NPC inverter, deduces the space voltage vector switch angle matrix of the three-phase equivalent modulation wave regulation sampling and the operation relationship. So, on the basis of the switch angle trajectory characteristics of SHEPWM and its realization by regulation sampling, the SHEPWM waveform pulse state can be gained by the vectors sequence special solution which composed of basic SV vector. To the three-level inverter, on the Two level small hexagon which be partitioned from space vector hexagon, the work sector allocation of SHEPWM pulse state be researched, and the corresponding basic SV vector and its action time also be achieved by the experiment and FFT analysis. This method avoid the solution of SHEPWM switch angle nonlinear transcendental equations, and it has the same effect of harmonic elimination and to facilitate online implementation.
Institute of Scientific and Technical Information of China (English)
宋文祥; 张旭
2012-01-01
在电机控制过程中,死区和管压降的存在导致逆变器输出波形畸变.为了消除电压和电流的畸变,死区和管压降补偿是必要的.本文给出了一种简洁高效的三电平电压型逆变器死区补偿方法,用以改善电机的输出波形,详细分析了死区产生机理,利用电流矢量对死区进行准确补偿.根据PWM状态和电流矢量的位置分析功率器件压降的变化,结合电流方向进行补偿.最后基于F2812DSP芯片的三电平逆变器实验平台对该方法进行了开环和闭环实验研究,验证了理论分析的正确性和实际可行性.%In order to prevent the output waveforms distortion due to dead-time and forward voltage, we must add the dead-time and forward voltage compensation in the process of motor control. This paper introduced a simple and efficient dead-time compensation method for three-level inverter to improve output waveforms. The cause of dead-time was analysed in detail, and dead-time can be compensated accurately using current vector. We analyse the changes in forward voltage of power devices based on PWM state and the position of current vector, and then compensate according to the current direction. Finally open and closed loop experiments are done to prove the proposed strategy through experiment on a three-level model inverter developed with F2812DSP. We can prove that the analysis is correct and the method can be used in practice.
Directory of Open Access Journals (Sweden)
Yap Hoon
2017-02-01
Full Text Available In this paper, a refined reference current generation algorithm based on instantaneous power (pq theory is proposed, for operation of an indirect current controlled (ICC three-level neutral-point diode clamped (NPC inverter-based shunt active power filter (SAPF under non-sinusoidal source voltage conditions. SAPF is recognized as one of the most effective solutions to current harmonics due to its flexibility in dealing with various power system conditions. As for its controller, pq theory has widely been applied to generate the desired reference current due to its simple implementation features. However, the conventional dependency on self-tuning filter (STF in generating reference current has significantly limited mitigation performance of SAPF. Besides, the conventional STF-based pq theory algorithm is still considered to possess needless features which increase computational complexity. Furthermore, the conventional algorithm is mostly designed to suit operation of direct current controlled (DCC SAPF which is incapable of handling switching ripples problems, thereby leading to inefficient mitigation performance. Therefore, three main improvements are performed which include replacement of STF with mathematical-based fundamental real power identifier, removal of redundant features, and generation of sinusoidal reference current. To validate effectiveness and feasibility of the proposed algorithm, simulation work in MATLAB-Simulink and laboratory test utilizing a TMS320F28335 digital signal processor (DSP are performed. Both simulation and experimental findings demonstrate superiority of the proposed algorithm over the conventional algorithm.
Institute of Scientific and Technical Information of China (English)
蒋丹; 刘福鑫; 毛韵雨; 阮新波
2014-01-01
In the hybrid renewable power system,a multi-port DC-DC converter can be introduced instead of the numerous individual DC-DC converters,leading to a simpler configuration and a lower cost.In high current applications,a Buck/Boost integrated three-port DC-DC converter with coupled inductors is proposed.Two interleaved inductors are introduced to obtain a symmetrical structure and achieve an inherent current sharing.For further optimization of the converter,two inductors can be coupled in an inverse manner.The converter topology is described,along with its control strategy and operating principle.The influence on the current ripples of the coupled inductors is discussed.The effective values of the current of switches and the zero voltage switching range with variable coupling coefficients are analyzed under ideal conditions.Finally,the theoretical analysis is validated by experimental results from a 1 kW prototype.%新能源联合供电系统中，多端口直流变换器可代替原有多个分立变换器，以简化系统结构、降低成本。针对大电流应用场合，提出一种采用耦合电感的 Buck/Boost 集成型三端口直流变换器，通过电感交错并联使桥臂结构一致，同时实现电流扩容与纹波抑制，将两电感反向耦合，进一步改善变换器性能。文中给出其拓扑结构与控制策略，讨论其工作原理，重点分析了电感电流脉动、开关管软开关实现范围及开关管电流有效值与耦合系数的关系，并通过一台1 kW的原理样机进行了实验验证。
Directory of Open Access Journals (Sweden)
S. Suresh Kumar,
2014-01-01
Full Text Available A modified pulse width modulation technique for Z-source inverter based BLDC motor is proposed and analyzed in this project.The Z-source inverter can be used as Buck/Boost converter with lower cost and high efficiency. BLDC motors are used in electric vehicles where portability and efficiency are required. This drive system provides advantages of both BLDC motors and Z-source inverter, and can be used in fuel cell system and other adjustable speed drive application. In this project principle of modified pulse width modulation technique is implemented and simulated. The model of a three phase Z-source inverter has been discussed based on modified pulse with modulation technique. The simulation of Z-source inverter based BLDC motor is done using the MATLAB/SIMULINK.
Institute of Scientific and Technical Information of China (English)
杜恩利; 何礼高; 李旭; 马彦林
2011-01-01
A significant problem with diode neutral point clamped three-level inverter is the fluctuation in the neutral-point voltage.The causes of the neutral point potential unbalance based on space vector pulse width modulation are analyzed. And then a strategy based on parameters self-tuning fuzzy logic control is presented which could solve the problems of some commonly used control strategies. For time-variable nonlinear system,this algorithm has better robustness and adaptability.Also there are small static and dynamic error in controlling of the neutral point voltage.The effectiveness of the proposed control approach is verified by simulation and experimental results.%中点电位平衡对二极管箝位三电平逆变器而言非常重要.在此深入分析了空间矢量调制中引起中点电位偏移的原因,提出了基于参数自整定模糊控制的中点平衡控制策略.该算法对三电平逆变器中点电位这一非线性时变对象有较好的适应性和鲁棒性,其静态及动态误差都能控制在较低范围,达到中点电位平衡的效果.仿真和实验结果证明了该算法的正确性和有效性.
Directory of Open Access Journals (Sweden)
Germán E. Melo
2014-08-01
Full Text Available Las lámparas fluorescentes compactas o CFL (compact fluorescent lamp se han convertido en uno de los tipos de iluminación más usados en la actualidad. Sin embargo, las CFL comerciales poseen en su mayoría balastros electrónicos de bajo factor de potencia. Esto genera un aumento en los niveles de distorsión del sistema de generación y distribución debido al uso masivo de estas lámparas. En el presente artículo se presenta el diseño y simulación de un balastro electrónico con corrección de factor de potencia para lámparas fluorescentes compactas. La propuesta busca evaluar la viabilidad de integrar el correcto funcionamiento, tamaño y costo de este dispositivo. La topología propuesta es una etapa buck-boost operando en modo de conducción discontinua integrada a un inversor alimentado por corriente. La alta factibilidad de implementación de esta topología es mostrada mediante simulaciones que logran un factor de potencia de 0.998 y una distorsión total armónica menor de 5 %.
Directory of Open Access Journals (Sweden)
Germán E. Melo
2014-05-01
Full Text Available Las lámparas fluorescentes compactas o CFL (compact fluorescent lamp se han convertido en uno de los tipos de iluminación más usados en la actualidad. Sin embargo, las CFL comerciales poseen en su mayoría balastros electrónicos de bajo factor de potencia. Esto genera un aumento en los niveles de distorsión del sistema de generación y distribución debido al uso masivo de estas lámparas. En el presente artículo se presenta el diseño y simulación de un balastro electrónico con corrección de factor de potencia para lámparas fluorescentes compactas. La propuesta busca evaluar la viabilidad de integrar el correcto funcionamiento, tamaño y costo de este dispositivo. La topología propuesta es una etapa buck-boost operando en modo de conducción discontinua integrada a un inversor alimentado por corriente. La alta factibilidad de implementación de esta topología es mostrada mediante simulaciones que logran un factor de potencia de 0.998 y una distorsión total armónica menor de 5 %.
Institute of Scientific and Technical Information of China (English)
徐文城; 刘尧; 王秀荣
2012-01-01
设计了一种宽输出电压的AC DC开关电源,其主要特征是输出电压可以在较大范围内任意调节,解决了传统的开关电源只能输出几个特定电压值的问题.该设计的核心是反激变换电路和Buck-Boost电路.分析了这两种电路的工作原理及其应用,并且给出了具体的设计.实验表明,设计的电源能较好地实现了输出电压的宽范围调节.%AC-DC switching power supply with a wide range voltage output was designed. Its main feature is that the output voltage can be adjusted in a wide range. The problem that the traditional switching power supplies only have few specific voltage outputs is solved in the design. The flyback convert circuit and Buck-Boost circuit are the cores of the design. The working principle and applications of these two circuits are analyzed. The concrete design is given in this paper. The experiments show that a wide range regulation of the output voltage has been more successfully achieved in the design of the power supply.
Power decoupling with autonomous reference generation for single-phase differential inverters
DEFF Research Database (Denmark)
Yao, Wenli; Zhang, Xiaobin; Wang, Xiongfei
2015-01-01
. However, the performance of existing active power decoupling methods depends heavily on certain control references, which unfortunately are parameter dependent. In this paper an autonomous reference generation technique is proposed for single phase differential inverter without relying on the system......The second-harmonic power ripple in single-phase inverter may introduce the issue of low reliability and low power density. In order to replace the bulky dc-link capacitor, an alternative approach is to use active power decoupling so that the ripple power can be diverted into other energy storages...... are used for realizing an improved power decoupling control, capacitor voltage and inductor current regulation. By substituting the corresponding parameter into unified model, the proposed control loop can be applied to different inverter types (Buck, Buck-Boost and Boost). Finally, detailed laboratory...
Institute of Scientific and Technical Information of China (English)
江才; 宋文胜; 王顺亮; 韩坤; 冯晓云
2014-01-01
针对电力牵引三电平中性点钳位(NPC)逆变器系统，首先分析了因调制算法引起的中点电位振荡现象。然后分别比较两种传统空间矢量脉宽调制(SVPWM)算法对中点电位振荡及负载电流总谐波畸变率(THD)的影响；在此基础上，以中点电位平衡控制和最小负载电流THD含量为目的，提出了一种基于中点电位环宽控制的 SVPWM算法。最后，通过 MALTAB/Simulink 软件仿真和dSPACE半实物平台实验研究，对3种调制算法下中点电位及负载电流 THD值进行对比分析。计算机仿真与半实物实验结果表明，中点电位环宽控制方法不但能平衡直流侧中点电位，而且能有效地减小负载电流THD含量。%The neutral-point voltage oscillation due to the modulation method is analyzed first for the three-level neutral-point-clamped (NPC) traction inverter.Then,the characteristics of the neutral-point voltage oscillation and the total harmonic distortion(THD)of load current due to two traditional space vector pulse width modulation(SVPWM)methods are compared with each other,respectively.On the basis of this,a SVPWM method with adj ustment of neutral-point hysteresis-loop width is proposed to balance the neutral-point and reduce the THD value of load current.Finally,both the amplitude of neutral-point oscillation and the THD value of load current are compared and analyzed via MATLAB/Simulink simulation and dSPACE hardware-in-the-loop experiment when the three modulation methods are adopted.Simulation and experimental results show that the adopted SVPWM method with neutral-point loop width control is efficient for balancing neutral-point voltage and reducing the THD value of load current.
Institute of Scientific and Technical Information of China (English)
姚川; 阮新波; 曹伟杰; 陈沛琳
2013-01-01
The two-switch Buck-Boost (TSBB) converter is suitable for wide input voltage applications, and a two-mode control scheme with two modulation signals and one carrier can be adopted to achieve high efficiency and automatic modes-switching over the entire input voltage range. The corresponding operating modes are the Buck mode with high input voltages and the Boost mode with low input voltage. In order to reduce the influence of the input voltage disturbance on the output voltage, input voltage feed-forward (IVFF) functions based on the small-signal models of different operating modes were derived, and the effect of the variable circuit parameters on the IVFF functions was analyzed, then a two-mode control scheme with IVFF compensation was proposed. With this proposed control scheme for the TSBB converter, automatic selections of operating modes and the corresponding IVFF functions can be achieved simultaneously. Besides, nearly smooth switching between Buck and Boost modes is guaranteed. Then, high efficiency and improved input transient response over the entire input voltage range are both achieved. For exhibiting the advantages of the proposed control scheme clearly, comparisons between the two-mode control with and without IVFF compensation had been presented in this paper. Finally, a suitable power prototype was fabricated to validate the effectiveness of the control scheme.% 双管Buck-Boost变换器适用于宽输入电压范围场合。采用双调制–单载波的两模式控制策略可实现其整个输入电压范围内的高效率和工作模式的自动平滑切换，其工作模式即为高输入电压区间的 Buck 模式和低输入电压区间的Boost模式。为抑制输入电压扰动对输出电压的影响，通过建立双管Buck-Boost变换器不同工作模式下的小信号模型，推导相应的输入电压前馈函数，并分析电路参数变化对前馈函数的影响，进而提出一种带输入电压前馈的两模式控制
Institute of Scientific and Technical Information of China (English)
孙孝峰; 申彦峰; 李午英; 王宝诚
2016-01-01
将交错并联双向 Buck/Boost 电路与全桥 LLC 谐振电路通过共用全桥开关单元集成在一起，提出了一种新型的三端口直流变换器，实现了器件共享，降低了体积和成本。该三端口变换器包括两个双向端口和一个隔离的单向输出端口，通过PWM+PFM的混合调制策略，可实现端口间功率流的灵活控制。与传统的移相全桥集成型三端口直流变换器相比，提出的变换器输入电流纹波小，可在宽电压和功率范围内实现一次侧开关管的零电压软开关（ZVS）和二次侧整流二极管的零电流软开关（ZCS）关断，开关损耗小，而且不存在占空比丢失、变压器直流偏磁等问题。研究了该三端口变换器的工作原理、工作模式和端口功率传输模式，并对其增益、软开关等特性进行了深入分析，最后搭建了一台500W的实验样机，实验结果验证了变换器的实用性和理论分析的正确性。%By integrating the two-phase interleaved bidirectional Buck/Boost circuit with the full-bridge LLC resonant circuit, a novel three-port converter (TPC) is proposed. Thus, the full-bridge switching unit is shared and the cost is reduced. The proposed TPC consists of two bidirectional DC ports and an isolated unidirectional DC port. With PWM plus PFM modulation strategy, flexible power flow control can be easily achieved. All primary power switches operate with ZVS and all secondary diodes can achieve ZCS-off in wide voltage and power ranges, thus the switching losses are reduced. In addition, the duty cycle loss and transformer DC bias current inherently existed in conventional phase shift full-bridge integrated TPCs, can be well eliminated in the proposed TPC combined with the LLC resonant tank. The basic operation principle, operation modes and power transfer modes of the proposed TPC are investigated. Then both the gain and the ZVS characteristics are analyzed in detail. Finally, the
Push-Pull Converter Fed Three-Phase Inverter for Residential and Motor Load
Directory of Open Access Journals (Sweden)
Samuel Rajesh Babu
2015-06-01
Full Text Available The proposed paper is an new approach for power conditioning of a PV (photo-voltaic cell array. The main objective is to investigate an approach to provide and improve the delivered electric energy by means of power conditioning structures with the use of alternative renewable resources (ARRs for remote rural residential or industrial non-linear loads. This approach employs a series-combined connected boost and buck boost DC-DC converter for power conditioning of the dc voltage provided by a photo-voltaic array. The input voltage to the combined converters is 100 V provided from two series connected PV cells, which is converted and increased to 200 V at the dc output voltage. Series-combined connected boost and buck-boost DC-DC converters operate alternatively. This helps to reduce the input ripple current and provide the required 400 Vdc on a sinusoidal PWM three-phase inverter. Analysis of the two series-combined DC-DC converters is presented along with simulation results. Simulations of the series-combined DC-DC converters are presented with an output DC voltage of 200 V and a maximum output load of Po = 600 W.
Institute of Scientific and Technical Information of China (English)
李雪莉
2011-01-01
针对有源无损缓冲电路结构和控制复杂的缺陷,开发了一种基于无源无损缓冲技术和谐振技术组合并在Buck/Boost变换器上实现,以此来设计具有非最小电压应力缓冲结构的软开关,通过对其7种工作模式下的工作流程分析,得到NMVS无源无损软开关电路单元并将缓冲元件的能量回馈给变换器的输入输出端,实现了无损的效果,并通过理论计算给出其具体的参数.与硬开关条件下的开关电流电压实验波形仿真对比,证实了其开关范围更广、效率更高、结构简单、性价比高,易于控制等优点.%Considering the shortcoming of active lossles snubber circuits and complicated control, a soft switching method which has voltage stress (MVS) passive lossless switching technology and resonant technology combined and implemented in Buck/Boost converters was proposed to develop a NMVS passive lossless soft switching. Through analyzing its working process in 7 different modes, the NMVS passive loss1ess soft switching circuit cell can feed back the energy of buffers to the converter input and output sides to achieve a loss1ess effect. The experimental result proves the success of theoretical analysis.
Institute of Scientific and Technical Information of China (English)
陈琪; 李旋
2013-01-01
针对一种具有优良电气特性的新型Buck-Boost矩阵变换器（BBMC）采用基于模糊PI的双闭环控制策略进行控制。阐述了该变换器的基本原理，研究了基于模糊PI的双闭环控制的具体设计方法。并采用MATLAB对其控制效果进行了仿真验证。结果表明：当BBMC输入侧电压发生突变时，模糊控制器能有效调节PI参数，使输出电压有效的跟随输入电压的变化而变化，从而系统迅速达到稳定。%According to a new Buck-Boost matrix converter (BBMC) having excellent electrical performance,uses the double closed loop control strategy based on fuzzy PI. This paper expounds the basic principle of the converter, studies the design method of double closed loop control based on fuzzy PI, and uses the MATLAB for the simulation of the control effect. The results show that, when the BBMC input voltage change, the fuzzy controller can effectively adjust the PI parameters, making the change of the output voltage effectively follow the change of the input voltage, thus the system rapidly reaches stable.
Directory of Open Access Journals (Sweden)
A. Santhi Mary Antony
2015-06-01
Full Text Available Current fed Quasi Z-Source Inverters (qZSI have the advantages of voltage buck-boost capability, improved reliability, reduced passive component ratings, continuous input current, a common dc rail between source and inverter and unique regeneration capability. This current-fed qZSIs are bidirectional with an additional diode, unlike the voltage-fed ZSI that needs a switch to achieve bidirectional power flow. Since current fed quasi Z Source Inverter has many advantages it can be employed for motor drive applications such as Brushless DC motor (BLDC drive. Therefore this study proposes the use of qZSI for BLDC motor. The simulation results for the same are presented in this study.
A Non-isolated Bidirectional Three-port Buck-Boost Converter%一种非隔离双向三端口升降压变换器
Institute of Scientific and Technical Information of China (English)
张君君; 吴红飞; 曹锋; 朱励厉; 邢岩
2014-01-01
A non-isolated three-port bidirectional DC-DC converter and its power control were proposed. The converter was derived from three bidirectional Buck/Boost switching cells cascaded with each other with DC-link capacitor removed. Compared with conventional solution of multiple bidirectional converters connected with a shared common DC bus, the proposed converter has the advantage of reduced size, lower cost and better reliability from DC-link capacitor eliminated, and it also greatly improved the efficiency and power density from single-stage step-up/-down conversion between any two of the multiple ports. The operational principles were analyzed in detail with power control and PWM strategy given. Finally, the topology and analysis were verified with the experimental results.%提出一种非隔离双向三端口升降压变换器拓扑及其功率控制策略。该变换器由3个双向Buck/Boost开关单元不通过直流母线电容级联组合而成；相对于传统多个变换器通过公共直流母线连接的解决方案，该变换器完全消除了中间母线电容，可减小变换器体积、重量和成本，提高系统可靠性，且任意两个端口之间均为单级升降压变换，大大提高了变换器的变换效率和功率密度。详细分析变换器的工作原理，给出相应的脉宽调制(pulse width modulation，PWM)和功率控制策略，最后通过实验验证理论分析的正确性。
Institute of Scientific and Technical Information of China (English)
杨晨; 谢少军; 毛玲; 秦岭
2012-01-01
Based on the control requirements of photovoltaic interface in the distributed DC power system, a control strategy for photovoltaic converter is proposed. Taking two-switch Buck-Boost converter for example, the control system structure for the converter is introduced and the small signal model is established. The operating principle is analyzed and how to select the close-loop control parameters is discussed. Finally, the control strategy was carried out on a 3 kW two-switch Buck-Boost converter. The experimental results show that the photovoltaic interface can work effectively to match the basic control requirements.%分析了分布式直流供电系统中光伏接口单元的控制要求,给出了相应的控制策略。以双管Buck-Boost变换器型接口单元为例,介绍了其控制系统结构和小信号模型的建立,分析了接口变换器的工作过程,讨论了闭环控制参数选取依据。最后,在一台3kW的双管Buck-Boost变换器实验样机上,对理论分析进行了验证,实现了分布式直流供电系统光伏接口单元的基本控制功能。
DEFF Research Database (Denmark)
Alrøe, Hugo Fjelsted
2016-01-01
This paper presents a second-order semiotic framework for ontological levels, which is based on the structure of semiosis in a more fundamental way than other existing approaches to semiotic levels. Building on the key semiotic concept of representation, three levels are posited: (1) non- or proto-semiotic...... processes, without representation, such as physical or causal processes, (2) semiotic processes, with representation, such as the processes of life and cognition, and (3) second-order semiotic processes, with representation of representation, such as self-conscious and self-reflexive communicative processes....... This semiotic framework for ontological levels is compared with recent discussions of different ontological kinds of kinds such as indifferent and interactive kinds. This leads to the distinction between not two, but three kinds of kinds: indifferent, adaptive and reflexive kinds, of which the last two hitherto...
具有大范围升-降压功能的新型单级逆变电路%A Novel High Voltage Ratio Single-Stage Inverter with Buck-Boost Ability
Institute of Scientific and Technical Information of China (English)
丁新平; 张承慧; 薛必翠; 张民
2014-01-01
提出一种具有大范围升-降压功能的单级逆变电路,简称高升压增益单级逆变器(HVRSSI).研究了其具体的工作模式和升-降压功能的实现机理,推导了电路各部分的电压关系.该变换器利用独特的LC结构代替了传统电压源逆变器直流侧的电容,利用逆变器上下管的“直通”实现了直流链电压VPN的大范围升压功能,同时提高了逆变器的可靠性.和现有单级逆变电路(譬如ZSIs)不同,HVRSSI电路的升压比B和直通占空比Dsh成反比,在较小的直通占空比时能够得到较高的升压比,克服了Z源逆变器等受“直通占空比Dsh和调制因子M相互制约”的限制而升压能力不足的缺陷.高升压增益逆变电路输出交流电压随调制因子M的变化趋势和传统电压源逆变器一致,随M的增大而增大,不同于其他单级逆变器,该一致性使得调节更快捷.通过实验室设计的lkW样机对所提电路进行相关性能检测,实验结果与理论分析和仿真研究完全符合,验证了所提变换器的有效性和实用性.
Institute of Scientific and Technical Information of China (English)
肖华锋; 谢少军
2010-01-01
双管Buck-Boost变换器拥有输入输出电压同极性和可升降压等特性,适合于两级式光伏并网逆变器中前级直流变换,但其同步开关方式需要较大的储能电感,且组合式开关方式控制电路复杂、实现工作模式无缝切换较困难.提出一种交错开关型双管Buck-Boost变换器,可使储能电感最小、控制电路简单,并实现无工作模式切换.分析了该变换器的工作原理和特性,比较3种开关方式下几个主要特性的优劣.最后通过一台3kW两级式并网逆变器,验证了所提变换器工作原理的正确性.
Institute of Scientific and Technical Information of China (English)
陈国呈; 宋文祥; 武慧; 孙承波
2006-01-01
This paper proposes a novel SVPWM ( space vector pulse width modulation) strategy for the three-level neutral-point-clamped voltage source inverter, based on the particular disposition of all the redundant voltage vectors. The new modulation approach shows superior performance for harmonic voltage and balancing control of neutral-point potential compared to the popular eight-stage centered SVPWM. It realizes suppression of inverter neutral-point potential variation by accurately modifying redundant factor of small vectorspairs, only requiring information of DC-link capacitor voltages and three-phase load currents. This is convenient to apply and is compatible of digital computer realization. Feasibility of the proposed control approach is verified by simulation and experimental results.
A Robust Chattering-Avoiding Sliding Mode Control for Buck-Boost Converter%一种鲁棒无抖颤滑模控制的Buck-Boost变换器
Institute of Scientific and Technical Information of China (English)
皇甫宜耿; 吴宇; 马瑞卿
2014-01-01
In the process of power generation by new energy sources, such as wind, light and hydrogen, the ran-domness of energy input and power output often appear;this puts forward higher requirements for the robust design of power converters. The power converter based on traditional sliding mode, due to its discrete control law, makes chattering phenomenon inevitable. In order to suppress the above problem, this paper presents a novel chattering-avoiding converter based on the super-twisting sliding modes. The core idea is to transfer the discrete control law to high order sliding manifold, essentially eliminating the impact of chattering effect. To remove the intermittent dis-turbance in the new energy power generation, this paper compares the effect of the converter controlled by super-twisting sliding mode controller with the classic PI controller in a typical Buck-Boost power converter as an example. The simulation results and their analysis show preliminarily that: (1) under the condition of large disturbances in input and output, the converter controlled by super-twisting sliding mode has stronger robustness;(2) in response tracking, the converter has a faster convergence;the frequency response can reach more than 20 Hz, far superior to the classic PI control.%利用风、光、氢等新能源发电过程中，经常遇到能量输入和功率输出的随机性，这对电源变换器鲁棒性设计提出了更高要求。针对传统滑模控制变换器由于自身控制律的离散型存在不可避免的抖颤问题，基于一种Super-Twisting控制算法设计无抖颤滑模变换器，其核心思想是将离散控制律转移至更高阶的滑模面，从本质上消除抖颤的影响。以电源变换器Buck-Boost为例，针对新能源发电中存在的间歇性扰动问题，与典型PI控制效果进行对比试验。仿真结果表明：1）动态滑模控制变换器在输入、输出大扰动下具有很强的鲁棒性；2）在频响跟踪方面具
基于LCL滤波器的三电平光伏并网逆变器控制策略%Control Strategy of Grid-connected Three-level PV Inverter with LCL Filter
Institute of Scientific and Technical Information of China (English)
段文燕
2013-01-01
In order to meet the requirement of grid-connected current harmonics with the IEEE Std. 1547 standard, the LCL filter is generally used in the grid-connected PV inverter applications to deeply attenuate high-frequency harmonics. However, the introduction of LCL filters will reduce the stability of system. In order to solve this problem, a novel passive damping control strategy is presented in this paper. Then parallel passive damping and system operation theory are analyzed in detail, and the stability is also studied. In the end, the presented control scheme is simulated by the MATLAB/Simulink. Simulation results show that the instability issue caused by LCL harmonics can be effectively resolved by proposed scheme, which guarantee the grid-connected current harmonics to conform to the IEEE. standards.%为了满足IEEE Std.1547标准对并网电流谐波的要求,光伏并网逆变器输出通常采用LCL滤波器抑制高频谐波.然而,LCL滤波器的引入导致系统稳定性降低.为了解决该问题,本文提出一种电感并联型无源阻尼控制方案.文中详细分析了并联无源阻尼和系统运行工作原理,并进行了稳定性分析.最后在MATLAB/Simulink环境下对控制方案进行验证.仿真结果表明,该方案可有效解决LCL谐振引起的不稳定问题,同时保证并网电流谐波含量满足IEEE标准.
Institute of Scientific and Technical Information of China (English)
陈艳慧; 陈道炼
2012-01-01
The combined DC-DC converter mode inverters with high frequency link is composed of two same isolated bi-directional DC-DC converters which are connected in parallel on the input side and reversely connected in series on the output side including Buck, Boost, and Buck-Boost mode. The circuit topology, control strategy, input current ripple, output voltage ripple, key parameters and test waveforms of three kinds of inverter were comparatively studied and an important conclusion was obtained.%组合直流变换器型高频环节逆变器是由两个相同的隔离双向直流变换器输入侧并联、输出侧反向串联构成,包括Buck、Boost、Buck-Boost型三类。主要对Buck、Boost、Buck-Boost组合直流变换器型高频环节逆变器的电路拓扑、控制策略、输入电流纹波、输出电压纹波、关键电路参数、原理实验波形等方面进行了比较研究,获得了重要结论。
Sano, Kenichiro; Fujita, Hideaki
This paper proposes a new voltage-balancing circuit for the split dc voltages in a diode-clamped five-level inverter. The proposed circuit is based on a resonant switched-capacitor converter (RSCC), which consists of two half-bridge inverters, a resonant inductor and a resonant capacitor. A new phase-shift control of the RSCC is proposed to improve voltage balancing performance. Theoretical analysis reveals the rating of the RSCC and stored energy in the resonant inductor. Experimental results confirm the reduction of the inductor to one tenth in volume as compared to a conventional voltage-balancing circuit based on buck-boost topology. Moreover, the proposed phase-shift control has demonstrated that it is possible to eliminate the voltage deviation between the dc capacitors.
Directory of Open Access Journals (Sweden)
Meenakshi T.
2016-09-01
Full Text Available This paper presents the modeling and simulation of a novel topology of quasi Z-Multilevel Inverter with stepped DC input. The proposed inverter incorporates a simple switching technique with reduced component count and is aimed at producing boosted multilevel output AC voltage. The inverter consists of two stages and the buck /boost operation is obtained by varying the shoot through period of the pulses obtained by maximum constant boost control with third harmonic injection. With all the advantages of the quasi Z-network, the proposed inverter eliminates the fly back diodes and capacitors present in a conventional Z-Multilevel Inverter. Further the stress on the devices is less which leads to reduction in component value and hence the cost. The novel stepped DC coupled Single Phase quasi Z-Multilevel Inverter is modeled and simulated in the MATLAB - SIMULINK environment and its performance is analyzed for varying input and switching conditions. The voltage and current waveforms across each stage of the inverter is analyzed and the results are presented for different levels of input.
Institute of Scientific and Technical Information of China (English)
毛惠丰; 孔德鹏; 陈增禄; 杨旭; 王兆安
2015-01-01
提出了一种单相 H 桥电压型逆变器三电平滞环电流跟踪控制方法。该控制方法具有载波移相PWM调制效果以及无死区效应的特点。在稳态条件下，误差电流被严格限制在内环中。当指令电流发生突变并且达到外环的上或下阈值时，逆变器输出最高或最低电平以使误差电流以最快速度趋近于0。与传统的三电平滞环电流控制方法相比，该控制方法能进一步改善逆变器输出电流的波形。通过仿真和实验结果验证了该方法的有效性。%ABSTRACT:A new three-level hysteresis current controller for single-phase H-bridge voltage source inverters (VSI) is proposed here. The proposed hysteresis current controller has successfully combined the advantage of the symmetrical unipolar carrier-based PWM and no dead-time effects. Under steady-state conditions, the current error will be confined within the inner band. When the commanded current step changes so that the current error exceeds the outer hysteresis band, the extreme voltage level is selected to force the current error towards zero quickly. Compared with the conventional three-level hysteresis current controller, the proposed hysteresis current controlled single-phase H-bridge voltage source inverters can further improve the inverter output current waveform. Simulated and experimental results have been given to demonstrate the validity and features of the novel hysteresis current controller with the improved switching scheme.
Institute of Scientific and Technical Information of China (English)
张旭辉; 温旭辉; 赵峰
2012-01-01
The DC bus voltage fluctuation suppression in the motor drive system with a bi-directional Buck/Boost converter was studied. The disadvantage that the power feed-forward control scheme cannot effectively suppress bus voltage fluctuation was analyzed. A novel direct power control scheme with bus capacitor energy outer control loop and output power inner control loop for the bi-directional Buck/Boost converter was presented. Moreover, in order to improve the dynamic response of converters, a feed-forward term which reflects the changing trends of output power was added on its duty cycle calculation node. The essential difference between the above two control schemes was compared. Results and simulations of the small-signal model analysis and experimental results show the direct power control scheme has good performance in voltage fluctuation suppression.%对电机驱动系统前置双向Buck/Boost变换器后直流母线电压的波动抑制问题进行研究.分析功率前馈控制策略抑制母线电压波动能力较弱的原因.对双向Buck/Boost变换器提出一种母线电容能量外环、输出功率内环的直接功率控制策略,并将输出功率的变化趋势反映到双向Buck/Boost变换器的发波环节,进一步提高了变换器的动态响应特性.基于小信号模型分析上述两种控制策略的本质区别.小信号模型分析结果、仿真和实验结果都证实,提出的直接功率控制策略比功率前馈控制策略有更好的抑制母线电压波动的能力.
Control of Cascaded Multilevel Inverters
Institute of Scientific and Technical Information of China (English)
无
2004-01-01
Abstract-A new type of multilevel inverter is introduced which is created by cascading two three-phase three-level inverters using the load connection, but requires only one DC voltage source. This new inverter can operateas a seven-level inverter and naturally splits the power conversion into a higher-voltage lower-frequency inverter and a lower-voltage higher-fre-quency inverter. This type of system presents particular advantages to Naval ship propulsion systems which rely on high power quality, survivable drives. New control methods are described involving both joint and separate control of the individual three-level inverters. Simulation resuits demonstrate the effectiveness of both controls. A laboratory set-up at the Naval Surface Warfare Center power electronics laboratory was used to validate the proposed joint-inverter control. Due to the effect of compounding levels in the cascaded inverter, a high number of levels are available resulting in a voltage THD of 9% (without filtering). Index Terms-Cascaded inverter, multilevel inverter, three-level inverter.
Institute of Scientific and Technical Information of China (English)
杨晨; 谢少军; 秦岭
2012-01-01
A control mode of two-switch Buck-boost converter using the coupling inductor to reduce the diodes reverse recover losses was proposed. The operation principle was analyzed and the theoretical calculation was iUustrated. Finally, the simulation and experiment result shows that the proposed asynchronous control mode could not only reduce the diodes reverse recovery losses and the additional switch on losses, but also improve the converter efficiency further.%提出了采用耦合电感的双管Buck-boost变换器的一种非同步控制方式。讨论了采用耦合电感降低续流二极管反向恢复损耗的原理，对比分析了同步与非同步工作方式下电路的工作原理和电路中各电流的理论计算结果．并通过仿真和实验进行了验证。研究表明，与同步控制方式相比，所提出的非同步控制方式可以减小双管Buck-boost变换器续流二极管反向恢复损耗，可以进一步提升变换器效率。
Institute of Scientific and Technical Information of China (English)
无
2005-01-01
A comparative study of hybrid system monitoring based on bond graph and Petri net modelling,A comparison of high-power converter topologies for the implementation of FACTS controllers,A Configuration and Control Method of DC Loop Type Distribution System - Including Distributed Generators,A Cost Effective Three-Level MOSFET Inverter for Low Power Drives,A discrete sliding mode control of a buck-boost inverter
Arctic research at three levels.
McNabb, Steven
2004-01-01
This paper is a posthumous publication of a Steven McNabb's presentation to the 1993 annual meeting of the American Anthropological Association. In it he described how the Social Transitions in the North research project involved explicit cross-cultural contact or participation at three levels: between scientists and public agencies; between scientists and study populations; and between research teams themselves. He explored a few of the entanglements and opportunities that arise in those interactions. Dr. McNabb urged northern researchers to avoid embracing rigid standards, for they will result in more entanglements and fewer opportunities. On the otherhand, if researchers are open-minded, they will be able to treat each dilemma as an opportunity that will make for better science.
Directory of Open Access Journals (Sweden)
E.Rajendran
2013-10-01
Full Text Available Wind energy is a leader area of application for variable-speed generators operating on the constant grid frequency. This paper depicts the power quality enhancement in wind power system using permanent magnet synchronous generator (PMSG and Quasi Z-source Inverter. The PMSG is connected to the power network by means of a quasi z-source inverter (qZSI. The PMSG are used by these technologies due to extraordinary characteristics such as a smaller amount weight and volume, superior performance, eradicate the gear box and no need of peripheral power in permanent magnet excitation. The PMSG overcome the induction generator and other generators, because of their splendid performances without take up the grid power. But Induction Generator always needs the grid connectionfor getting power to start. In this paper the quasi Z-source inverter is a present that is a novel topology conjugated from the traditional Z source Inverter. The qZSI inherits all the advantages of the ZSI, that is performs buck-boost, inversion and power control in wind energy conversion system (WECS Moreover, the proposed qZSI the matchless advantages of less component ratings and stable dc current from the source. All over boost control methods are built for the ZSI can be used by the qZSI .This Paper presents hysteresis current control technique for the quasi Z- source inverter.
Institute of Scientific and Technical Information of China (English)
胡存刚; 芮涛; 马大俊; 王群京; 罗方林
2016-01-01
The active neutral point clamped (ANPC) topology enable additional switch states and commutations compared to the neutral point clamped (NPC) topology. ANPC topology can overcome disadvantages of unequal semiconductor loss distribution in NPC topology. This paper investigated the control strategy of the neutral-point potential (NP) balancing and the switching loss (SL) reduction for three-level ANPC inverters. An novel three-level space vector pulse width modulation (SVM) was proposed to control the NP imbalance and to reduce the SL simultaneously. The novel virtual medium vectors were redefined, which were synthesized by the original medium vector and the adjacent two pairs of small vectors. Therefore, using the proposed VSVM, there are two pairs of small vectors in any region of the space vector diagram, which one pair of small vectors can be used to control the NP, and another pair of small vectors can be used for reducing the SL. The coordinately selected small vectors consider both the NP charge and the pulse sequence, so that the minimized NP ripple and switching events are guaranteed in one switching cycle. The simulation and experimental results are provided to verify the effectiveness of the proposed control strategy.%有源中点钳位型拓扑通过选择冗余开关状态和不同的电流通路能够有效控制器件的损耗平衡。论文对三电平有源中点钳位型逆变器中点电压平衡和开关损耗减少的控制策略进行研究，提出一种中点电压平衡和减小损耗的三电平空间矢量调制方法。将虚拟中矢量重新定义，新的虚拟中矢量由原中矢量和邻近的两对小矢量合成，因此参考矢量在空间矢量图的任何区域都有两个成对的正负小矢量参与合成，其中一个优先用于控制中点电压的平衡，另外一个可以用于其他控制目标。在每个开关周期内根据中点电压波动和开关序列选择合适的小矢量，在控
Institute of Scientific and Technical Information of China (English)
肖飞; 谢桢; 吕昊
2013-01-01
In order to improve the wave of voltage, a delay signal cancel(DSC) method has been used to distinguish and control the positive and negative sequence components. However, while reinforcing the voltage waveform, the method increases the imbalance of the current, which results in seriously neutral-point voltage oscillating, under the space vector pulse width modulation (SVPWM). Thus, impact of the negative sequence current to neutral-point voltage oscillation is calculated. The results show that the neutral-point control ability could be increased or decreased with the negative sequence component increasing, which is mostly depended on the power factor. When the modulate proportion is bigger than 0. 5, the neutral-point control ability can be descend to zero because of the inconsonance between the power factor and negative sequence gene. Moreover, the boundary of the ability to control the unbalance by controlling the redundant voltage small vectors is found. Therefore the neutral-point control SVPWM is built. Plus, a integrate control strategy for three-level neutral-point clamped (NPC) voltage source inverter with unbalanced load based on distinguishing and controlling the positive and negative sequence components by DSC is put forward. Simulation exhibit that by the presented method, the negative sequence voltage can be restrained, and the negative sequence current makes the neutral-point unbalanced, while the voltage fluctuation at the neutral-point is controlled by the integrate control strategy. It is proved that under the integrated control strategy, three-level NPC voltage source inverter( VSI) performs well with unbalance load.%为了改善不平衡负载条件下三电平中点钳位型(NPC)电压型逆变器的输出电压波形,采用了延迟信号撤销法(DSC)分离出正序和负序电压分量分别进行控制.但此方法在修正了电压波形的同时,会进一步增加输出电流的不对称性,导致在空间矢量脉宽调制算法(SVPWM)
Enhanced Z-source Inverters%增强型Z源逆变器
Institute of Scientific and Technical Information of China (English)
蔡春伟; 曲延滨; 盛况
2011-01-01
Z源逆变器利用特殊的X型LC网络实现升降压功能,同桥臂允许直通,提高了逆变器的可靠性.但传统Z源逆变器的升压能力有限,不适用于需要高升压增益的场合.提出一种增强型Z源逆变器拓扑,其具有以下优点:显著增强了逆变器的升压能力,扩大了Z源逆变器的应用场合；实现高调制因子,提高整个逆变器输出的电能质量；有效地降低Z源网络电容的电压应力,有助于减小系统的体积和成本.对增强型拓扑进行了稳态分析,仿真和实验结果验证了该逆变器拓扑的特点.%With a unique X-shaped LC network connected between its dc power source and inverter topology, a Z-source inverter can gain buck-boost ability and improve the reliability utilizing the shoot-through states which cannot be realized by a traditional inverter. However, the boosting capability of traditional Z-source inverter is limited and not be suitable for applications requiring very high boost inversion ability. An enhanced Z-source inverter topology with strong voltage boost inversion ability was proposed to expand the scope of application. Only a short shoot-through interval is required to obtain high voltage conversion ratios, so the modulation factor can be higher, which is conductive to improve the output power quality. Further more, the Z-source capacitor voltage stress is reduced greatly and thus can help to reduce the system cost and volume. The topology was analyzed in steady state, and simulation and experimental results were presented to validate the performances of the enhanced topology.
Study on three level system population transfer
Institute of Scientific and Technical Information of China (English)
Shan Yang(杨山); Ye Kuang(旷冶)
2003-01-01
Stimulated-Raman-adiabatic-passage (STIRAP) process provides an effective technique to transfer electronpopulation from an initial state (e.g. ground state) to excited final state for both atoms and molecules. Inthis paper, we present the results of the study on electron population transfer in three level system. Wehave analyzed the effects of various conditions on the transfer process, such as the time delay of the twolaser beams, two-photon off-resonance, one-photon off-resonance and the change of relative laser intensity.The numerical result is compared with experiment, and the reasons for the effects are also given.
Control and design of full-bridge three-level converter for renewable energy sources
DEFF Research Database (Denmark)
Yao, Zhilei; Xu, Jing; Guerrero, Josep M.
2015-01-01
of rectifier diodes is high and filter is large in traditional voltage-source converters in a wide input-voltage range. In order to solve the aforementioned problems, a full-bridge (FB) three-level (TL) converter is proposed. It can operate at both two-level and three-level modes, so it is suitable for wide......Output voltage of renewable energy sources, such as fuel cell and PV cell, is often low and varies widely with load and environmental conditions. Therefore, the high step-up DC-DC converter is needed between renewable energy sources and the grid-connected inverter. However, voltage stress...
Three-level cervical disc herniation
Directory of Open Access Journals (Sweden)
St. Iencean Andrei
2015-09-01
Full Text Available Multilevel cervical degenerative disc disease is well known in the cervical spine pathology, with radicular syndromes or cervical myelopathy. One or two level cervical herniated disc is common in adult and multilevel cervical degenerative disc herniation is common in the elderly, with spinal stenosis, and have the same cause: the gradual degeneration of the disc. We report the case of a patient with two level cervical disc herniation (C4 – C5 and C5 – C6 treated by anterior cervical microdiscectomy both levels and fusion at C5 – C6; after five years the patient returned with left C7 radiculopathy and MRI provided the image of a left C6 – C7 disc herniation, he underwent an anterior microsurgical discectomy with rapid relief of symptoms. Three-level cervical herniated disc are rare in adults, and the anterior microdiscectomy with or without fusion solve this pathology.
Hybrid-source impedance network and its generalized cascading concepts
DEFF Research Database (Denmark)
Li, Ding; Gao, Feng; Loh, Poh Chiang;
2009-01-01
. It is anticipated that these concepts and their formed inverters can find applications in photovoltaic and other renewable systems, which in turn motivate the investigation initiated here on two-level and three-level generalized cascading concepts. In addition to their theoretical performance merits, practical......Hybrid-source impedance networks have attracted attention among researchers because of their flexibility in performing buck-boost energy conversion. To date, three distinct types of impedance networks can be summarized for implementing voltage-type inverters, with another three types summarized...
Periodically driven three-level systems
Kenmoe, M. B.; Fai, L. C.
2016-09-01
We study the dynamics of a three-level system (ThLS) sinusoidally driven in both longitudinal and transverse directions and in the presence of a uniaxial anisotropy D entering the generic Hamiltonian through the zero-energy splitting term D (Sz)2 where Sz is the projection of the spin vector along the quantization direction. As a consequence of the addition of this term, the order of the symmetry group of the Hamiltonian is increased by a unit and we observe a sequence of cascaded SU(3) Landau-Zener-Stückelberg-Majorana (LZSM) interferometers. The study is carried out by analytically and numerically calculating the probabilities of nonadiabatic and adiabatic evolutions. For nonadiabatic evolutions, two main approximations based on the weak and strong driving limits are discussed by comparing the characteristic frequency of the longitudinal drive with the amplitudes of driven fields. For each of the cases discussed, our analytical results quite well reproduce the gross temporal profile of the exact numerical probabilities. This allows us to check the range of validity of analytical results and confirm our assumptions. For adiabatic evolutions, a general theory is constructed allowing for the description of adiabatic passages in arbitrary ThLSs in which direct transitions between states with extremal spin projections are forbidden. A compact formula for adiabatic evolutions is derived and numerically tested for some illustrative cases. Interference patterns demonstrating multiple LZSM transitions are reported. Applications of our results to the nitrogen vacancy center in diamond are discussed.
Synchronised PWM Schemes for Three-level Inverters with Zero Common-mode Voltage
DEFF Research Database (Denmark)
Oleschuk, Valentin; Blaabjerg, Frede
2002-01-01
PWM with synchronous smooth pulses-ratio changing and a quarter-wave symmetry of the voltage waveforms. Three basic versions of both algebraic and trigonometric synchronised PWM have been analysed. Simulations give the behaviour of the proposed methods and show some advantage of synchronised PWM...
DEFF Research Database (Denmark)
Oleschuk, Valentin; Blaabjerg, Frede
2002-01-01
of the voltage waveforms during the whole control range including overmodulation. Continuous, discontinuous and "direct-direct" schemes of synchronous PWM with both algebraic and trigonometric control functions have been analysed and compared. Simulations give the behaviour of the proposed methods and show some...
DEFF Research Database (Denmark)
Oleschuk, Valentin; Blaabjerg, Frede
2002-01-01
of the voltage waveforms during the whole control range including overmodulation. Continuous, discontinuous and "direct-direct" schemes of synchronous PWM with both algebraic and trigonometric control functions have been analysed and compared. Simulations give the behaviour of the proposed methods and show some...
Institute of Scientific and Technical Information of China (English)
贺文婷
2015-01-01
This paper discusses the issue related to Inverted Order. There are two forms of Inversion, which are Partial Inversion and Complete Inversion. I analyze three main reasons of Inversion and its usages in details. And what’s more, under what conditions should we use Inverted construction? How can we distinguish the different usages of Complete Inversion and Partial Inversion? In this paper, I will talk more details about Inversion.%本篇论文讨论有关倒装语序的问题。倒装有两种形式，即部分倒装和完全倒装。文中分析了倒装的三个原因及其用法。具体的，在什么情况下需要使用倒装结构？我们如何区分完全倒装和部分倒装的不同用法？本篇论文将作具体阐述。
Directory of Open Access Journals (Sweden)
K.Mohan Krishna
2015-12-01
Full Text Available Multilevel inverter topology has developed recently as a very important alternative in the area of high power medium voltage energy control. In multilevel inverter, thethree basic types of topologies used are diode clamped inverter (neutral point clamped, capacitorclamped (flying capacitor and cascaded multi cell with separate dc sources. Multilevel inverters are used in medium voltage and high power applications with less harmonic contents. This paper proposes a software implementation of neutral point clamped (NPC three level voltage source inverter using space vector pulse width modulation (SVPWM techniques. The inverter feeds an electrical system which is controlled by field oriented control (FOC.The improvement of the control technique is achieved using intelligence techniques. The operation of the electrical system is verified in steady state and transient state responses. This software implementation is performed by using matlab/Simulink software. This paper gives comparison between SVPWM three phase three level with neutral point clamped and without neutral point clamped. Finally, the comparative study of different techniques was implemented.
Sliding mode control of solid state transformer using a three-level hysteresis function
Institute of Scientific and Technical Information of China (English)
刘宝龙; 査亚兵; 张涛
2016-01-01
The solid state transformer (SST) can be viewed as an energy router in energy internet. This work presents sliding mode control (SMC) to improve dynamic state and steady state performance of a three-stage (rectifier stage, isolated stage and inverter stage) SST for energy internet. SMC with three-level hysteresis sliding functions is presented to control the input current of rectifier stage and output voltage of inverter stage to improve the robustness under external disturbance and parametric uncertainties and reduce the switching frequency. A modified feedback linearization technique using isolated stage simplified model is presented to achieve satisfactory regulation of output voltage of the isolated stage. The system is tested for steady state operation, reactive power control, dynamic load change and voltage sag simulations, respectively. The switching model of SST is implemented in Matlab/ Simulink to verify the SST control algorithms.
Three-Level AC-DC-AC Z-Source Converter Using Reduced Passive Component Count
DEFF Research Database (Denmark)
Loh, Poh Chiang; Gao, Feng; Tan, Pee-Chin;
2009-01-01
to switch with a three-level output voltage, where the middle neutral potential is uniquely tapped from the star-point of a wye-connected capacitive filter placed before the front-end diode rectifier for input current filtering. Through careful control, the resulting converter can produce the correct volt......-second average at its output, while simultaneously achieving inductive voltage boosting by shooting through either an appropriately selected inverter phase-leg or two phase-legs being commanded simultaneously. More interestingly, these performance features are achieved with no increase in the number...
INVERTER MULTI LEVEL TIPE JEMBATAN SATU FASA TIGA TINGKAT DENGAN MIKROKONTROLER AT89S51
Directory of Open Access Journals (Sweden)
A. Warsito A. Warsito
2012-02-01
Full Text Available Inverter is a power electronics circuit which is used to convert DC voltage and current to AC voltage andcurrent. In conventional inverter, most commonly used, only has three level voltage, those are +Vdc, -Vdc,and zero. Meanwhile both square inverters and SWPM inverter has big harmonic distortion. In SPWMinverter scheme, high frequency switching must be used to minimize total harmonic distortion (THD. Multilevel inverter is a type of inverter that has more than one level of voltage and current output.The major advantages of multi level inverters are a good voltage waveform, small harmonic dirtortion,switching component operated under low frequency, and it can supply a big power.This paper will discuse the construction of single phase three level multi level inverters, hardware testinginclude output waveform THD, and the comparisson of multilevel inverter with other conventional invertersscheme suc as PWM inverters modulation, and square waveform inverter. Atmel’s AT89S51 microcontrollerused to control switching scheme in this multi level inverter. By this power electronic circuit, it is expected alow cost and reliable multi level inverters prototipe.
Analytic Solutions of Three-Level Dressed-Atom Model
Institute of Scientific and Technical Information of China (English)
WANG Zheng-Ling; YIN Jian-Ping
2004-01-01
On the basis of the dressed-atom model, the general analytic expressions for the eigenenergies, eigenstates and their optical potentials of the A-configuration three-level atom system are derived and analysed. From the calculation of dipole matrix element of different dressed states, we obtain the spontaneous-emission rates in the dressed-atom picture. We find that our general expressions of optical potentials for the three-level dressed atom can be reduced to the same as ones in previous references under the approximation of a small saturation parameter. We also analyse the dependences of the optical potentials of a three-level 85Rb atom on the laser detuning and the dependences of spontaneous-emission rates on the radial position in the dark hollow beam, and discuss the probability (population) evolutions of dressed-atomic eigenstates in three levels in the hollow beam.
Sliding Mode Control of Three Levels Back-To-Back VSC-HVDC System Using Space Vector Modulation
Directory of Open Access Journals (Sweden)
Bouafia Saber
2014-03-01
Full Text Available In this study, a sliding mode strategy proposed to control a three levels Back-to-Back High Voltage Direct Current (HVDC system based on the three-level voltage source converter (VSC. The voltage-balancing control of two split DC capacitors of the VSC-HVDC system is achieved using three-level space vector modulation with balancing strategy based on the effective use of the redundant switching states of the inverter voltage vectors. Finally, a complete simulation of the VSC-HVDC system validates the efficiency of the proposed strategy law. Compared to the conventional control, Sliding Mode Control scheme for the VSC-HVDC system shows the attractive advantages such as offering high tracking accuracy, fast dynamic response and good robustness.
Superradiant phase transitions with three-level systems
Baksic, Alexandre; Nataf, Pierre; Ciuti, Cristiano
2013-02-01
We determine the phase diagram of N identical three-level systems interacting with a single photonic mode in the thermodynamical limit (N→∞) by accounting for the so-called diamagnetic term and the inequalities imposed by the Thomas-Reich-Kuhn (TRK) oscillator strength sum rule. The key role of transitions between excited levels and the occurrence of first-order phase transitions is discussed. We show that, in contrast to two-level systems, in the three-level case the TRK inequalities do not always prevent a superradiant phase transition in the presence of a diamagnetic term.
Superradiant phase transitions with three-level systems
Baksic, Alexandre; Ciuti, Cristiano
2013-01-01
We determine the phase diagram of $N$ identical three-level systems interacting with a single photonic mode in the thermodynamical limit ($N \\to \\infty$) by accounting for the so-called diamagnetic term and the inequalities imposed by the Thomas-Reich-Kuhn (TRK) oscillator strength sum rule. The key role of transitions between excited levels and the occurrence of first-order phase transitions is discussed. We show that, in contrast to two-level systems, in the three-level case the TRK inequalities do not always prevent a superradiant phase transition in presence of a diamagnetic term.
40 CFR 761.346 - Three levels of sampling.
2010-07-01
... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Three levels of sampling. 761.346... PROHIBITIONS Sampling Non-Liquid, Non-Metal PCB Bulk Product Waste for Purposes of Characterization for PCB Disposal in Accordance With Â§ 761.62, and Sampling PCB Remediation Waste Destined for Off-Site...
Exploration and Planning in a Three-Level Cognitive Architecture
DEFF Research Database (Denmark)
Kraft, Dirk; Baseski, Emre; Popovic, Mila;
2008-01-01
We describe an embodied cognitive system based on a three-level architecture that includes a sensorimotor layer, a mid-level layer that stores and reasons about object-action episodes, and a high-level symbolic planner that creates abstract action plans to be realised and possibly further specifi...
On three-level problem of competitive pricing
Plyasunov, A.; Panin, A.
2016-10-01
We propose a new pricing model that are designed for the study of competitive pricing. As pricing strategies we use the uniform and discriminatory pricing. We formulate the model as a three-level quadratic programming problem with integer and boolean variables. To solve few cooperative formulations of this model we develop polynomial-time algorithms.
A Three-level 4 x 3 Conventinal Matrix Converter
DEFF Research Database (Denmark)
Rong, Runjie; Loh, Poh Chiang; Wang, Peter;
2007-01-01
This paper proposes a topology of a three-level 4 × 3 conventional matrix converter with 12 bi-directional switches. PWM control and modulation index compensation have been investigated. Operation theory has been verified by the simulation results using Matlab. The simulation results show that th...
Inverted organic photosensitive devices
Energy Technology Data Exchange (ETDEWEB)
Forrest, Stephen R.; Bailey-Salzman, Rhonda F.
2016-12-06
The present disclosure relates to organic photosensitive optoelectronic devices grown in an inverted manner. An inverted organic photosensitive optoelectronic device of the present disclosure comprises a reflective electrode, an organic donor-acceptor heterojunction over the reflective electrode, and a transparent electrode on top of the donor-acceptor heterojunction.
Energy Technology Data Exchange (ETDEWEB)
Zhao, Zilai [General Motors LLC, Detroit, MI (United States); Gough, Charles [General Motors LLC, Detroit, MI (United States)
2016-04-22
The goal of this Cooperative Agreement was the development of a Next Generation Inverter for General Motors’ electrified vehicles, including battery electric vehicles, range extended electric vehicles, plug-in hybrid electric vehicles and hybrid electric vehicles. The inverter is a critical electronics component that converts battery power (DC) to and from the electric power for the motor (AC).
升降式交流斩波器%Buck-Boost AC/AC Direct Converter
Institute of Scientific and Technical Information of China (English)
孙刚; 洪峰
2009-01-01
介绍了一种新颖的Buck-Boost型交流斩波器.该交流斩波器将Buck-Boost型DC/DC变换器的开关管双向化,可实现单级降压或升压的AC/AC直接变换和能量双向流动.该变换器使用较少的功率器件实现了单级功率变换和能量双向流动,有利于提高变换器的功率密度和变换效率.详细研究了其工作模态和原理.分析了该变换器的两种PWM调制策略,并指出采用第2种调制策略可降低开关损耗.采用滞环电流控制的Buck/Boost型交流斩波器可对输入电压畸变进行有效抑制,保持了输出电压波形的高度正弦化.仿真和实验验证了分析的正确性.
A New Buck-Boost Converter for a Hybrid-Electric Drive Stand
Directory of Open Access Journals (Sweden)
P. Mašek
2009-01-01
Full Text Available This paper describes work on the laboratory working stand for a hybrid-electric drive located in laboratory T2:H1-26.The basic idea is to operate the combustion engine in its optimal regime. In this regime the engine has the highest efficiency and minimal smoke exhaust. This optimal regime is only a small portion of its operation area. Because the engine has to operate in this area, it is necessary to add a new converter to the hybrid-electric stand. The new converter must be allowed to buck and boost and must operate as a current source in this regime.
一种新颖的Buck-Boost变换器%A Novel Buck-Boost Converter
Institute of Scientific and Technical Information of China (English)
方宇; 谢勇; 邢岩
2003-01-01
提出了一种新颖的两开关电路拓扑,它能工作在宽输入交流电压范围,并实现功率因数校正(PFC).新拓扑与单开关Buck-Boost变换器和传统的两开关串级Buck-Boost变换器及其它Buck-Boost变换器相比有显著的性能改善,如:器件应力及损耗较低,不需要解决浪涌电流问题,电感尺寸也较小.分析了拓扑工作原理,并给出了实验结果.
一种新型Buck-Boost变换器%A Novel Buck-Boost Converter
Institute of Scientific and Technical Information of China (English)
高飞; 蒋赢; 赵小妹; 潘俊民
2010-01-01
提出了一种新型Buck-Boost变换器,与传统的Buck-Boost变换器相比,该电路利用开关电容网络,能在相同的输入电压和开关管占空比情况下具有更好的降压效果.对该新型Buck-Boost变换器的工作原理进行了分析,并通过仿真和实验验证了该方案的可行性.实验表明,该新型Buck-Boost变换器能够实现较好的降压效果,输出效果良好.
Equivalent classes of closed three-level systems
Plenio, M. B.
2001-01-01
In recent years a significant amount of research in quantum optics has been devoted to the analysis of atomic three-level systems and for many physical quantities the same effects have been predicted for different configurations. These configurations can be split into essentially two classes. One for which the system contains a metastable state and another where the system has two close-lying levels and coherence effects become important. We demonstrate when and why for a wide range of parame...
Long-lasting inverted photon echo and optical memory
Energy Technology Data Exchange (ETDEWEB)
Akhmediev, N.N.; Borisov, B.S.; Zuikov, V.A.; Samartsev, V.V.; Stel' makh, M.F.
1988-06-01
Experimental results are presented on the formation of the long-lasting inverted stimulated photon echo in the LaF3:Pr(3+) crystal. The physics of this phenomenon is explained on the basis of a three-level model. The feasibility of using this echo effect in the development of optical-memory systems is considered. 18 references.
Vulnerability of complex networks under three-level-tree attacks
Hao, Yao-hui; Han, Ji-hong; Lin, Yi; Liu, Lin
2016-11-01
We investigate vulnerability of complex networks including model networks and real world networks subject to three-level-tree attack. Specifically, we remove three different three-level-tree structures: RRN (Random Root Node), MaxDRN (Max Degree Root Node) and MinDRN (Min Degree Root Node) from a network iteratively until there is no three-level-tree left. Results demonstrate that random network is more robust than scale-free network against three tree attacks, and the robustness of random network decreases as the increases. And scale-free network shows different characteristics in different tree attack modes. The robustness of scale-free is not affected by the parameters for RRN, but increases as the increases for MinDRN. The important thing is that MaxDRN is the most effective in the three tree attack modes, especially for scale-free network. These findings supplement and extend the previous attack results on nodes and edges, and can thus help us better explain the vulnerability of different networks, and provide an insight into more tolerant real complex systems design.
A Three-level BDDC algorithm for saddle point problems
Energy Technology Data Exchange (ETDEWEB)
Tu, X.
2008-12-10
BDDC algorithms have previously been extended to the saddle point problems arising from mixed formulations of elliptic and incompressible Stokes problems. In these two-level BDDC algorithms, all iterates are required to be in a benign space, a subspace in which the preconditioned operators are positive definite. This requirement can lead to large coarse problems, which have to be generated and factored by a direct solver at the beginning of the computation and they can ultimately become a bottleneck. An additional level is introduced in this paper to solve the coarse problem approximately and to remove this difficulty. This three-level BDDC algorithm keeps all iterates in the benign space and the conjugate gradient methods can therefore be used to accelerate the convergence. This work is an extension of the three-level BDDC methods for standard finite element discretization of elliptic problems and the same rate of convergence is obtained for the mixed formulation of the same problems. Estimate of the condition number for this three-level BDDC methods is provided and numerical experiments are discussed.
Directory of Open Access Journals (Sweden)
Nagarathna M
2015-06-01
Full Text Available Solar energy the most efficient, eco-friendly and abundantly available energy source in the nature. It can be converted into electrical energy in cost effective manner. In recent years, the interest in solar energy has risen due to surging oil prices and environmental concern. In many remote or underdeveloped areas, direct access to an electric grid is impossible and a photovoltaic inverter system would make life much simpler and more convenient. With this in mind, it is aimed to design, build, and test a solar panel inverter. This inverter system could be used as backup power during outages, battery charging, or for typical household applications. The main components of this solar system are solar cell, dc to dc boost converters, and inverter. Sine wave push pull inverter topology is used for inverter. In this topology only two MOSFETs are used and isolation requirement between control circuit and power circuit is also less which helps to decrease the cost of solar inverter.
DEFF Research Database (Denmark)
Zhang, Zhe; Anthon, Alexander; Andersen, Michael A. E.
2014-01-01
frequencyincreases due to high switching loss of the equipped high voltagepower switches. In order to reduce switching loss and herebyenhance efficiency, a newly proposed circuit-level decouplingmodulation (CLDM) scheme is applied for these two widely usedthree-phase three-level inverters, as well...... as their correspondingloss analyses are addressed. The switching loss reduction isevaluated comprehensively undervariant modulation indices andload power factors. The analysis results reveal that the CLDM isan alternative discontinuouspulse-width modulation (DPWM)approach for inverters with high switching frequencies...
Improved inverted Stepanov apparatus
Berkman, S.; Temple, H. E.
1979-01-01
Modifications in inverted Stepanov process improve heat transfer and energy efficiency in growing silicon ribbon crystals. Using system, silicon is directly heated by induction, minimizing heat transfer and contamination problems.
An EMTDC Model of a Three Level four MVAR Compensator
DEFF Research Database (Denmark)
Rasmussen, Tonny Wederberg
1997-01-01
The paper discusses the dynamic characteristics of a three level ±4mvar solid state var compensator which is built and will be used for dynamic reactive power compensation in a wind farm. An investigation has been carried out of the influence of the compensator reactor, the DC intermediate voltage...... capacitor and the losses of the compensator for its speed of control, specially its response to fast phase shift in the grid. Furthermore the need for DC midpoint control will be compared with the inherent stabilisation. The harmonics made by the midpoint control will be compared with the harmonics without...
DEFF Research Database (Denmark)
Siwakoti, Yam P.; Town, Graham; Loh, Poh Chiang;
2014-01-01
This paper introduces a new 3-phase Y-source inverter whose gain is presently not matched by classical impedance-network-based inverters operating at the same duty ratio. The proposed network uses a tightly coupled transformer with three windings. By squeezing the shoot-through range while keeping....... This design flexibility was proven mathematically, and is supported by simulations carried out to prove the concept and validate the analysis....
Semistar Invertibility on Integral Domains
Institute of Scientific and Technical Information of China (English)
Marco Fontana; Giampaolo Picozza
2005-01-01
A natural development of the recent work about semistar operations leads to investigate the concept of "semistar invertibility". Here, we show the existence of a "theoretical obstruction" for extending many results, proved for star-invertibility, to the semistar case. For this reason, we introduce two distinct notions of invertibility in the semistar setting (called *-invertibility and quasi-*-invertibility), we discuss the motivations of these "two levels" of invertibility and we extend, accordingly, many classical results proved for the d-, v-, t- and w-invertibility.
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.
Consciousness, Mind, and Spirit: Three Levels of Human Cognition
Directory of Open Access Journals (Sweden)
Andrej Ule
2015-10-01
Full Text Available The article elucidates three important concepts and realities that refer to cognitive phenomena and are often (mistakenly used as synonyms: consciousness (slo. zavest, mind (slo. um, and spirit (slo. duh. They present three levels of human cognition: individual-experiential, individual-mental, and trans-individual-mental. Simply put: the concept of consciousness pertains to the waking mental life of a human being, while the concept of mind pertains to the ability and activity to consciously comprehend and understand contents and objects of human activity. I delineate three “types” of spirit: personal spirit, objective spirit, and the objectification of spirit in productions of human culture; I have doubts, however, about the existence of cosmic or super-cosmic dimensions of spirit, although some interpretations of quantum physics and modern cosmology suggest that such dimensions are possible.
Three-level description of the domino cellular automaton
Czechowski, Zbigniew
2010-01-01
Inspired by the approach of kinetic theory of gases, a three-level description (microscopic, mesoscopic and macroscopic) of cellular automaton is presented. To provide an analytical treatment a simple domino cellular automaton with avalanches was constructed. Formulas concerning exact relations for density, clusters, avalanches and other parameters in an equilibrium state were derived. It appears that some relations are approximately valid for deviations from the equilibrium, so the adequate Ito equation could be constructed. The equation provides the time evolution description of some variable on the macroscopic level. The results also suggest a motive for applying of the procedure of construction of the Ito equation (from time series data) to natural time series.
Matched Pulse Propagation in a Three-Level System
Park, Q H
1997-01-01
The Bãcklund transformation for the three-level Maxwell-Bloch equation is presented in the matrix potential formalism. By applying the Bãcklund transformation to a constant electric field background, we obtain a general solution for matched pulses (a pair of solitary waves) which can emit or absorb a light velocity solitary pulse but otherwise propagate with their shapes invariant. In the special case, this solution describes a steady state pulse without emission or absorption, and becomes the matched pulse solution recently obtained by Hioe and Grobe. A nonlinear superposition rule is derived from the solitons as well as nonabelian breathers. Various new features of these solutions are addressed. In particular, we analyze in detail the scattering of "invertons", a specific pair of different wavelength solitons one of which moving with the velocity of light. Unlike the usual case of soliton scattering, the broader inverton changes its sign through the scattering. Surprisingly, the light velocity inverton re...
CONSTRUCTING UNIFORM DESIGNS WITH TWO- OR THREE-LEVEL
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
When the number of runs is large, to search for uniform designs in the sense of low-discrepancy is an NP hard problem. The number of runs of most of the available uniform designs is small (≤ 50). In this article, the authors employ a kind of the so-called Hamming distance method to construct uniform designs with two- or three-level such that some resulting uniform designs have a large number of runs. Several infinite classes for the existence of uniform designs with the same Hamming distances between any distinct rows are also obtained simultaneously. Two measures of uniformity, the centered L2-discrepancy (CD, for short) and wrap-around L2-discrepancy (WD, for short), are employed.
A Novel Space Vector Technique for the Direct Three-level Matrix Converter
Directory of Open Access Journals (Sweden)
C. Agees Kumar
2014-10-01
Full Text Available This study proposes a novel Direct Torque Control (DTC method for the Direct Three level Matrix Converter (DTMC, which uses both the input phase voltage vectors (short vectors and the input line voltage vectors (long vectors. The problem of voltage imbalance at the input filter capacitance due to the use of the short vectors is addressed with an additional voltage hysteresis comparator. With the errors of torque, flux, sin Ψ and the neutral point voltage, an Optimum Switching Table (OST is designed for the DTMC. The OST generates the necessary switching signals for the DTC of the DTMC. The DTMC topology with the modified ISVM technique reduces the THD at the output. The proposed DTMC Indirect Space Vector pulse width Modulation (ISVM technique uses the idea of multilevel inverter SVM technique along with the proposed neutral current balancing strategy for generating the firing pulses. The switching loss model for the DTMC is developed and the performance of the DTMC is compared with that of the Conventional Matrix Converter (CMC. The performance of the proposed DTC technique for the DTMC is evaluated through simulation to explain the reduced torque ripple characteristics. To validate the proposed DTMC ISVM technique, a 3 kVA direct multilevel matrix converter prototype was developed.
Energy Technology Data Exchange (ETDEWEB)
Mozaffari Niapour, S.A.KH., E-mail: s.a.kh.mozaffari.niapour@gmail.com [Faculty of Electrical and Computer Engineering, University of Tabriz, 51664 Tabriz (Iran, Islamic Republic of); Danyali, S.; Sharifian, M.B.B.; Feyzi, M.R. [Faculty of Electrical and Computer Engineering, University of Tabriz, 51664 Tabriz (Iran, Islamic Republic of)
2011-08-15
Highlights: {yields} Employing the BLDC motor in water pumping systems. {yields} Utilizing the ZSI as a single-stage power converter in the PV water pumping systems based on BLDC motor. {yields} Improvement of the conventional IC MPPT method with the fuzzy logic control scheme to save more energy from the PV array. {yields} Taking the advantages of the DTC drive of the BLDC motor. {yields} Optimizing the water pumping system speed response characteristic by PSO. - Abstract: This paper discusses operation performance of a water pumping system consist of a brushless dc (BLDC) motor coupled a centrifugal pump and accompanying a Z-source inverter (ZSI) fed by a photovoltaic (PV) array, to be improved. Despite conventional double-stage power converters, this paper proposes utilizing a single-stage ZSI to extract the maximum power of the PV array and supply the BLDC motor simultaneously. Utilizing the ZSI provides some inherent advantages such as high efficiency and low cost, which is very promising for PV systems due to its novel voltage buck/boost capability. In addition, in order to precisely perform the maximum power point tracking (MPPT) of the PV array the fuzzy logic-incremental conductance (FL-IC) MPPT scheme is proposed. The proposed FL-IC MPPT scheme provides enough modification to the conventional IC method to enjoy an appropriate variable step size MPPT control signal for the ZSI. Moreover, direct torque control (DTC) is found more effective in comparison with hysteresis current control with current shaping to drive the BLDC motor, because it benefits from faster torque response, reduced torque ripple, less sensitivity to parameters variations, and simple implementation. In the mean time, due to the frequently variations of the PV power generation; delivered mechanical power to the centrifugal pump is variable. Thus, the BLDC motor should be driven with variable reference speed. In order to improve the speed transient response of the BLDC motor and enhance
Inverter communications using output signal
Energy Technology Data Exchange (ETDEWEB)
Chapman, Patrick L.
2017-02-07
Technologies for communicating information from an inverter configured for the conversion of direct current (DC) power generated from an alternative source to alternating current (AC) power are disclosed. The technologies include determining information to be transmitted from the inverter over a power line cable connected to the inverter and controlling the operation of an output converter of the inverter as a function of the information to be transmitted to cause the output converter to generate an output waveform having the information modulated thereon.
Inverting the Linear Algebra Classroom
Talbert, Robert
2014-01-01
The inverted classroom is a course design model in which students' initial contact with new information takes place outside of class meetings, and students spend class time on high-level sense-making activities. The inverted classroom model is so called because it inverts or "flips" the usual classroom design where typically class…
Inverted organic photovoltaic cells.
Wang, Kai; Liu, Chang; Meng, Tianyu; Yi, Chao; Gong, Xiong
2016-05-21
The advance in lifestyle, modern industrialization and future technological revolution are always at high expense of energy consumption. Unfortunately, there exist serious issues such as limited storage, high cost and toxic contamination in conventional fossil fuel energy sources. Instead, solar energy represents a renewable, economic and green alternative in the future energy market. Among the photovoltaic technologies, organic photovoltaics (OPVs) demonstrate a cheap, flexible, clean and easy-processing way to convert solar energy into electricity. However, OPVs with a conventional device structure are still far away from industrialization mainly because of their short lifetime and the energy-intensive deposition of top metal electrode. To address the stability and cost issue simultaneously, an inverted device structure has been introduced into OPVs, bridging laboratory research with practical application. In this review, recent progress in device structures, working mechanisms, functions and advances of each component layer as well their correlations with the efficiency and stability of inverted OPVs are reviewed and illustrated.
A Three Level Autonomous Software System for Increased Science Return
Robinson, P. I.; Mancinelli, R. L.; Landheim, R.
2005-12-01
The development of smart science instruments for autonomous operation (on Earth or in space) has the potential to increase science return and reduce the risk of experiment failure. When researchers are confronted with unexpected data/results of the experimental test system, they must determine whether the experimental setup has failed, or scientific discovery is being made. These two classes of events could have the same time series signature. To directly address this issue, we have developed a three-level software system referred to as E3, which consists of an engineering level, an experiment level, and an executive level. Each level of the software system is designed in a modular fashion using model based feedback controllers. The same feedback control mechanism is used for each level; the model itself determines the level. To determine if failure of the experimental setup can explain the data/results, researchers run calibration tests for hardware (e.g., sensors and actuators) as well as verify that the software (e.g., controls and analog to digital conversion routines) is running as planned. If anomalies are found, then modifications are made to the experimental setup, or the anomaly is accepted as the new baseline state of the instrument. The engineering level of the E3 software system is responsible for this process. To determine if scientific discovery, as opposed to failure, can explain the data/results, a researcher tries to explain the difference between the observed and expected results. These explanations are terms of the basic processes of nature to determine the rate limiting step(s) of a complex set of processes, where the flux could be due to heat transfer, mass transfer, momentum transfer, or chemical reaction processes. Once the differences are understood, modifications are made to the software control of the experiment, as well as to the model the researcher is building over the course of repeated experiments. The experiment level of the E3
Energy Technology Data Exchange (ETDEWEB)
Blackmon, J.B.
1979-07-01
Implications of employing a non-inverting heliostat design with a lower capital cost relative to an inverting design are considered from three standpoints: (1) effects of dust buildup, corresponding cleaning frequencies, and resultant cleaning costs; (2) effects of hail impact; and (3) refleccted beam safety issues. It is concluded that elimination of the inverting stow hardware and addition of reflector area in the slot required for inverting the reflector provides a direct subsystem cost savings. Since the non-inverting heliostat must be stowed face-up during high winds, reflectance degradation rates due to dust buildup are increased. The economic optimum cleaning frequency and allowed loss of reflectance due to dust buildup are determined so as to minimize the total system cost, and it is found that an overall cost savings of 12-13 percent results if the inverting capability is eliminated. Hail impact damage and probability of occurrence for the United States are determined within the accuracy of available data. Analysis indicates that the commercial heliostat laminate glass design considered will survive 1 1/2 inch hailstones and is suitable for installation over most of the US with low to negligible risk from hail damage. Reflected beam safety hazards are analyzed for the non-inverting design relative to the inverting design. No compelling reason is found to require an inverting stow capability, and therefore, a non-inverting stow heliostat is concluded to be a viable, cost-effective option.
DEFF Research Database (Denmark)
Anthon, Alexander
Renewable energies have experienced a significant growth and importance in the last two decades, of which energy from photovoltaic plants are a major contributor. Since solar cells have low efficiencies themselves, however, the necessity of high efficiency power converters at low cost...... and preferably low complexity leads to new research demands. This is especially true in the field of low cost residential PV inverters where efficiencies are used as major selling arguments. Traditional converter topologies equipped with conventional Silicon based semiconductors to date reach their limitations...
Asymmetrical Γ-Source Inverters
DEFF Research Database (Denmark)
Wei, Mo; Poh Chiang, Loh; Blaabjerg, Frede
2014-01-01
, inverters with coupled transformers have been introduced, but they usually lead to high turns ratio, and hence many winding turns, at high gain. An alternative would then be the asymmetrical Γ-source inverters proposed in this paper, whose gain is raised by lowering their turns ratio toward unity. The input...... current drawn by the proposed inverters is smoother and, hence, more adaptable by the source. Theories and experimental results have been presented in this paper for validating the concepts proposed....
Comparison of Modulation Techniques for Multilevel Inverter fed Permanent Magnet Synchronous Motor
Directory of Open Access Journals (Sweden)
V. NAGA BHASKAR REDDY
2010-10-01
Full Text Available Multilevel inversion is a power conversion strategy in which the output voltage is obtained in steps thus bringing the output closer to a sine wave and reduces the Total Harmonic Distortion. Multilevel inverter structures have been developed to overcome shortcomings in solid-state switching device ratings so that they can be applied to higher voltage systems. In recent years, the multilevel inverters have drawn tremendous interest in the area of high-power medium-voltage energy control. Three different topologies have been proposed for multilevel inverters like Diode-Clamped Inverter, Capacitor Clamped Inverter and Cascaded Multi cell Inverter. In addition, several modulation and control strategies have been developed or adopted for multilevel inverters including the following multilevel Sinusoidal Pulse Width Modulation (SPWM, and Space Vector Modulation. In this paper, simulation of various modulating techniques i.e., Pulse Width Modulate techniques such as Sinusoidal PWM, Trapezoidal PWM, Stepped PWM, Stair case PWM, third harmonicinjected PWM, Modified SVPWM are applied for both Diode Clamped Three-Level Inverter and Diode Clamped Five-Level Inverter, and Space Vector PWM technique are analyzed for DC3LI. The best modulationtechnique are extended to Permanent Magnet Synchronous Motor.
DEFF Research Database (Denmark)
Chiang Loh, Poh; Gao, Feng; Blaabjerg, Frede
2010-01-01
of embedded EZ-source inverters that can produce the same gain as the Z-source inverters but with smoother and smaller current/voltage maintained across the dc input source and within the impedance network. These latter features are attained without using any additional passive filter, which surely...... is a favorable advantage, since an added filter will raise the system cost and, at times, can complicate the dynamic tuning and resonant consideration of the inverters. The same embedded concept can also be used for designing a full range of voltage- and current-type inverters with each of them tested...
DEFF Research Database (Denmark)
Blaabjerg, Frede; Loh, Poh Chiang; Gao, F.
2008-01-01
-voltage oscillations to the system. Therefore, Z-source inverters are in effect safer and less complex, and can be implemented using only passive elements with no additional active semiconductor needed. Believing in the prospects of Z-source inverters, this paper contributes by introducing a new family of embedded EZ...... since an added filter will raise the system cost, and at times can complicate the dynamic tuning and resonant consideration of the inverters. The same embedded concept can also be used for designing a full range of voltage and current-type inverters with each of them tested experimentally using a number...
Applications of cascade multilevel inverters
Institute of Scientific and Technical Information of China (English)
彭方正; 钱照明
2003-01-01
Cascade multilevel inverters have been developed for electric utility applications. A cascade M-level inverter consists of (M-1)/2 H-bridges in which each bridge's dc voltage is supported by its own dc capacitor. The new inverter can: (1) generate almost sinusoidal waveform voltage while only switching one time per fundamental cycle; (2) dispense with multi-pulse inverters' transformers used in conventional utility interfaces and static var compensators; (3) enables direct parallel or series transformer-less connection to medium- and high-voltage power systems. In short, the cascade inverter is much more efficient and suitable for utility applications than traditional multi-pulse and pulse width modulation (PWM) inverters. The authors have experimentally demonstrated the superiority of the new inverter for power supply, (hybrid) electric vehicle (EV) motor drive, reactive power (var) and harmonic compensation. This paper summarizes the features, feasibility, and control schemes of the cascade inverter for utility applications including utility interface of renewable energy, voltage regulation, var compensation, and harmonic filtering in power systems. Analytical, simulated, and experimental results demonstrated the superiority of the new inverters.
Applications of cascade multilevel inverters
Institute of Scientific and Technical Information of China (English)
彭方正; 钱照明
2003-01-01
Cascade multilevel inverters have been developed for electric utility applications. A cascade M-level inverter consists of (M-1)/2 H-bridges in which each bridge's dc voltage is supported by its own de ca-pacitor. The new inverter can : ( 1 ) generate almost sinusoidal waveform voltage while only switching one timeper fundamental cycle ; (2) dispense with multi-pulse inverters' transformers used in conventional utility in-terfaces and static var compensators; (3) enables direct parallel or series transformer-less connection to medium- and high-voltage power systems. In short, the cascade inverter is much more efficient and suitable for utility applications than traditional multi-pulse and pulse width modulation (PWM) inverters. The authors have experimentally demonstrated the superiority of the new inverter for power supply, (hybrid) electric vehicle (EV) motor drive, reactive power (var) and harmonic compensation. This paper summarizes the features,feasibility, and control schemes of the cascade inverter for utility applications including utility interface of renewable energy, voltage regulation, var compensation, and harmonic filtering in power systems. Analytical,simulated, and experimental results demonstrated the superiority of the new inverters.
Simulation of inverter dominated minigrids
Energy Technology Data Exchange (ETDEWEB)
Engler, A.; Osika, O. [Inst. fuer Solare Energieversorgungstechnik (ISET) e.V., Kassel (Germany)
2003-07-01
In order to assess the load flow, the transient behaviour and the stability of inverter dominated minigrids, a model for inverters and a transmission system has been developed. The inverters are represented by a frequency and voltage controlled three phase voltage source and the transmission systems consists of switches, overhead lines ({pi}-equivalent), transformers and a load. The inverters operate in parallel via the MV-distribution system and supply an active load. The contribution of each inverter is determined by the setting of the applied droops (similar to conventional power plants). Furthermore an approach for stability assessment of such systems is introduced. This research work is related to the EC-funded project MicroGrids. (orig.)
Single-Phase 3L PR Controlled qZS Inverter Connected to the Distorted Grid
DEFF Research Database (Denmark)
Makovenko, Elena; Husev, Oleksandr; Roncero-Clemente, Carlos
2016-01-01
This paper presents a single-phase three-level NPC qZS inverter connected to a distorted grid using PID and PR regulators. A case study system along with the control strategy are described. Tuning approaches for PID and PR regulators are addressed and validated by means of simulation results...
Analyze and Improve Lifetime in 3L-NPC Inverter from Power Cycle and Thermal Balance
DEFF Research Database (Denmark)
Chen, Quan; Chen, Zhe; Wang, Qunjing
2014-01-01
Three-level Neutral-point-clamped (3L-NPC) topology is becoming a realistic alternative to the conventional one in high-voltage and high-power application. Studies show that the power cycling mean time to failure (MTTF) of the semiconductor bond wire in 3L-NPC inverter system may be very short un...
Transformerless PV inverters. Final report
Energy Technology Data Exchange (ETDEWEB)
Borup, U.
2009-12-15
Since the start of the project the market for grid connected PV inverters have developed further. When the project started three - phase inverter were only available in high power systems. The technology developed within this project will enable three phase technology also to be implemented in string inverters for system down to 10 kW. We expect this to be very attractive due to the increased demand for symmetrical feed-in to the grid. The project relevance is therefore high and the sector continues to develop very much driven by technology. Especially the inverter technology is getting a lot of focus. The inverter systems are expected to take a much larger role in supporting the electrical grid in the future. The technology platform developed within the project is prepared to be extended with these utility functionalities. The main results of the project were: 1) A new technology concept for transformer-less inverters has been demonstrated with a number of prototypes. 2) Efficiency above 97,7% has been proven. 3) Efficiency and Maximum power point tracking has been optimized to ensure that almost all energy produced of the panels is transferred to the grid. 4) The platform is developed with a very fast control board, which enables extended functionality as demanding grid supporting functions in the future. Details about cost price and details about the control loop implementation is excluded from the report due to the competitive situation for Danfoss Solar Inverters A/S. (LN)
Modulation of Current Source Inverter
Directory of Open Access Journals (Sweden)
Golam Reza Arab Markadeh
2011-04-01
Full Text Available Direct torque control with Current Source Inverter (CSI instead of voltage source inverter is so appropriate because of determining the torque of induction motor with machine current and air gap flux. In addition, Space-Vector Modulation (SVM is a more proper method for CSI because of low order harmonics reduction, lower switching frequency and easier implementation. This paper introduces the SVM method for CSI and uses the proposed inverter for vector control of an induction motor. The simulation results illustrate fast dynamic response and desirable torque and speed output. Fast and accurate response to changes of speed and load torque reference completely proves the prominence of this method.
Institute of Scientific and Technical Information of China (English)
DAIHong-Yi; KUANGLe-Man; LICheng-Zu
2005-01-01
We propose a scheme to probabilistically teleport an unknown arbitrary three-level two-particle state by using two partial entangled two-particle states of three-level as the quantum channel. The classical communication cost required in the ideal probabilistic teleportation process is also calculated. This scheme can be directly generalized to teleport an unknown and arbitrary three-level K-particle state by using K partial entangled two-particle states of three-level as the quantum channel.
Directory of Open Access Journals (Sweden)
Jelena Loncarski
2015-04-01
Full Text Available The standard solution for the traction system in battery powered electric vehicles (EVs is a two-level (2L inverter feeding a three-phase motor. A simple and effective way to achieve a three-level (3L inverter in battery-supplied electric vehicles consists of using two standard three-phase 2L inverters with the open-end winding connection of standard three-phase ac motors. The 3L inverter solution can be usefully adopted in EVs since it combines several benefits such as current ripple reduction, increment of phase motor voltage with limited voltage ratings of the two battery banks, improvement in system reliability, etc. The reduction in current ripple amplitude is particularly relevant since it is a source of electromagnetic interference and audio noise from the inverter-motor power connection cables and from the motor itself. By increasing the inverter switching frequency the ripple amplitude is reduced, but the drive efficiency decreases due to the proportionally increased switching losses. In this paper the peak-to-peak ripple amplitude of the dual-2L inverter is evaluated and compared with the corresponding ripple of the single-2L inverter, considering the same voltage and power motor ratings. The ripple analysis is carried out as a function of the modulation index to cover the whole modulation range of the inverter, and the theoretical results are verified with experimental tests carried out by an inverter-motor drive prototype.
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)
Inverter Ground Fault Overvoltage Testing
Energy Technology Data Exchange (ETDEWEB)
Hoke, Andy [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Nelson, Austin [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Chakraborty, Sudipta [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Chebahtah, Justin [SolarCity Corporation, San Mateo, CA (United States); Wang, Trudie [SolarCity Corporation, San Mateo, CA (United States); McCarty, Michael [SolarCity Corporation, San Mateo, CA (United States)
2015-08-12
This report describes testing conducted at NREL to determine the duration and magnitude of transient overvoltages created by several commercial PV inverters during ground fault conditions. For this work, a test plan developed by the Forum on Inverter Grid Integration Issues (FIGII) has been implemented in a custom test setup at NREL. Load rejection overvoltage test results were reported previously in a separate technical report.
Invertibility in L-Topological Spaces
Directory of Open Access Journals (Sweden)
Anjaly Jose
2014-03-01
Full Text Available In this paper, we extend the concept of invertibility to L-topological spaces and delineate its properties. Then, we study further completely invertible L-topological spaces and introduce two types of invertible L-topologies based on the inverting maps, studying their sums, subspaces and simple extensions.
Control and Modeling of Push-Pull Forward Three-Level Converter for Microgrid
DEFF Research Database (Denmark)
Yao, Zhilei; Xu, Jing; Guerrero, Josep M.
2015-01-01
Renewable energy sources are widely used in microgrid. Output voltage of them is often low and varies widely. Because diodes in three-level legs in traditional three-level (TL) converter are substituted by MOSFETs, the push-pull forward (PPF) TL converter is very suitable for wide and low...
THD Reduction in Performance of Cascaded Multi-Level Inverter Fed Induction Motor Drive
Directory of Open Access Journals (Sweden)
Naveen Kumar Verma
2013-12-01
Full Text Available The multilevel inverter power structure plays a vital role in the power industry. It is easier to produce a high-power, high-voltage inverter with the multilevel structure. The topologies of multilevel inverter have several advantages such as lower total harmonic distortion (THD, lower electromagnetic interference (EMI generation, reduction of voltage ratings of the power semiconductor switching devices and high output voltage. This paper presents a universal control scheme based on multicarrier PWM methods and its implementation in three-level, five-level and nine-level cascaded inverters feeding a three phase induction motor. This paper compares total harmonic distortion values of voltage and current waveforms of induction motors between different levels.
SIMPLIFIED SVPWM ALGORITHM BASED DIODE CLAMPED 3-LEVEL INVERTER FED DTC-IM DRIVE
Directory of Open Access Journals (Sweden)
C. HARI KRISHNA
2012-05-01
Full Text Available This paper presents a simplified space vector pulse width modulation (SVPWM based diode clamped threelevel inverter fed direct torque controlled (DTC induction motor drive. The space vector diagram of three-level inverter is simplified into two-level inverter. So the selection of switching sequences is done as conventional two-level SVPWM method. Thus, the proposed algorithm reduces the complexity involved in the PWM algorithm. To validate the proposed PWM lgorithm, several simulation studies have been carried and resultsare presented. From the results, it can be observed that the proposed algorithm reduces the total harmonic distortion (THD of the line current and line voltages when compared with the 2-level inverter fed induction motor drive.
2016-01-01
In recent days, fractional calculus (FC) has been accepted as a novel modeling tool that can extend the descriptive power of the traditional calculus. Fractional-order descriptiveness can increase the flexibility and degrees of freedom of the model by means of fractional parameters. Based on the fact that real capacitors and inductors are “intrinsic” fractional order, fractional calculus is introduced into the modeling process to establish a fractional-order state-space averaging model of the...
π型Buck-Boost交流变换器%π Type Buck-Boost AC/AC Converter
Institute of Scientific and Technical Information of China (English)
张友军; 翁振明; 王阿敏; 项家希
2012-01-01
提出一种对称结构π型Buck-Boost交流变换器及其变结构控制策略.该变换器由Buck交流单元和Boost交流单元组成,与级联式两级电路相比,省去前级LC输出滤波器,简化了电路结构.根据前、后单元的工作与否,π型交流变换器存在4种工作模式:Buck模式、Boost模式、直通模式和Buck -Boost模式.通过等效改变电路结构,变结构控制策略使得π型Buck-Boost交流变换器只有3种工作模式:Buck模式、Boost模式和直通模式.π型Buck -Boost交流变换器虽然具有两个独立的控制对象、采用两级占空比调制,但实际上最多只有一级功率变换,且存在直接功率传递通路,适用于稳压或调压应用场合.
零纹波输入电流Buck-Boost变换器%Zero Rippled Input Current Buck-Boost Converter
Institute of Scientific and Technical Information of China (English)
陆治国; 林贤贞; 胡红琼; 邓文东
2008-01-01
针对传统Buck-Boost输入输出电流断续的缺点,提出一种基于独立电感零纹波输入电流和输出电流连续的Buck-Boost变换器,详细分析了变换器的稳态工作原理.采用状态空间平均法,建立了变换器动态小信号模型,给出了小信号特征Matlab仿真波形.并对其进行交错并联优化,最后Saber电路仿真证明了理论分析的正确性.
The Simulation Research of Buck-Boost Converter%Buck-Boost变化器的仿真分析
Institute of Scientific and Technical Information of China (English)
李雪莉
2010-01-01
PSpice是一款功能强大的电路仿真软件,仿真结果十分接近电路的真实状态.应用PSpice对Buck-Boost变换器的全部工作过程进行了仿真与分析,Buck-Boost电路的工作过程包括电路启动时的瞬态工作过程和稳态工作过程.对电路中储能元件的各种工作状态进行了分析,给出了大量直观的仿真波形,从而更进一步了解了Buck-Boost变换器.
Directory of Open Access Journals (Sweden)
Latha. S. C
2014-11-01
Full Text Available The portable devices development of semiconductor manufacturing technology, conversion efficiency, power consumption, and the size of devices have become the most important design criteria of switching power converters. For portable applications better conveniences extension of battery life and improves the conversion efficiency of power converters .It is essential to develop accurate switching power converters, which can reduce more wasted power energy. The proposed topology can achieve faster transient responses when the supply voltages are changed for the converter by making use of the feed forward network .With mode select circuit the conduction & switching losses are reduced the positive buck–boost converter operate in buck, buck–boost, or boost converter. By adding feed-forward techniques, the proposed converter can improve transient response when the supply voltages are changed. The designing, modeling & experimental results were verified in MATLAB/ Simulink. The fuzzy logic controller is used as controller.
Energy Technology Data Exchange (ETDEWEB)
Lee, H. [Kyungnam University (Korea, Republic of)
1996-10-27
A soft switching method with small switching loss was proposed for the purpose of increasing the efficiency of a DC-DC boost converter which converted a DC current generated by solar cells to a variable DC current. Existing current converters are supplemented by using a snubber circuit around the switch so as to protect the switch by a hard switching action. However, with an increase of the output current, snubber loss is increased, reducing the efficiency. In order to solve this problem, the partial resonant switch method was applied to the converter; with this method of partially forming a resonant circuit only at the time of turning on/off of the switch, the switching loss was reduced through the soft switching, thereby making the proposed converter operate with high efficiency. Moreover, the resonant element of the partial resonant circuit using a snubber condenser, the energy accumulated in the condenser was regenerated on the power supply side without loss of snubber. With the regenerated energy, the proposed converter was provided with a smaller ratio of switching to use than the conventional converter. 4 refs., 7 figs., 1 tab.
Institute of Scientific and Technical Information of China (English)
刘国海; 钱鹏; 陈兆岭; 沈跃; 廖志凌
2013-01-01
A NPC three-level inverter is suitable to be used in the field of high power, high voltage. A DC side neutral-point N and three-phase bridge arm neutral-point O of a traditional NPC three-level inverter were linked together. The voltage of the three-phase bridge arm neutral-point would fluctuate, because of the DC side neutral-point voltage fluctuation. It would influence the efficiency of the NPC three-level inverter’s work. The neutral-point voltage excessive fluctuation of the traditional neutral point clamped (NPC) three-level inverter would cause the total harmonic distortion (THD) of output voltage increase and switch devices damage. This problem limits its engineering applications in the field of agriculture. A NPC three-level inverter topology with a neutral-point voltage self-balancing function was proposed. It consisted of two parts. Part 1 was the traditional NPC three-level inverter. Part 2 was the active compensation voltage device, and was composed of a single-phase full-bridge inverter circuit, which was used to compensate for the voltage fluctuation of a three-phase bridge arm neutral-point in a traditional NPC three-level inverter. The active compensation voltage device is similar to a controllable voltage source. It was used in a series between point O and point N in a traditional NPC three-level inverter. The three-phase bridge arm neutral-point real-time voltage value was detected and compared with a given value. Then, a real-time compensation voltage was generated by the active compensation voltage device. The voltage of the three-phase bridge arm neutral-point was uo, the voltage of the DC side neutral-point was un, and the voltage of the DC side was us. The real-time compensation voltage was ub, o n bu =u −u . When the neutral-point voltage of part 1 fluctuates excessively, the active compensation voltage device would generate a real-time compensation voltage to keep neutral-point voltage stability, o su =0.5u . Because coordinate
Grid Connected WECS with A Five Level DCMLI using PID Controller
Directory of Open Access Journals (Sweden)
G.Balaji
2014-07-01
Full Text Available This paper deals with the analysis, modeling and control system for permanent magnet synchronous generator (PMSG based wind turbine connected to the grid. A wind energy conversion using DC-DC Buck- Boost Converter for permanent magnet synchronous generator (PMSG based variable speed wind energy conversion system (WECS has been proposed which is integrated with grid using five-level diode clamped multilevel (DCMLI inverter. In this work the instantaneous values of input side current and voltage of DC-DC buck-boost converter are utilized for implementing the PID controller. The proposed work is verified by the simulation in Powersim.
Directory of Open Access Journals (Sweden)
Rashmi S
2014-03-01
Full Text Available This paper proposes the Dynamic modeling and performance analysis of Permanent magnet synchronous generator (PMSG based Wind Generation System (WGS. This system consists of Wind Turbine, PMSG, Diode Rectifier, Buck- Boost converter, Voltage source Inverter (VSI. PMSG and Buck Boost converter are employed in WGS to get efficient output according to the load requirement without damaging the system. The output of the VSI is injected to the grid and used for Home Application. The proposed model dynamic simulation results are tested in MATLAB Simulink
Simplified design of switching power supplies
Lenk, John
1996-01-01
Simplified Design of Switching Power Supplies is an all-inclusive, one-stop guide to switching power-supply design. Step-by-step instructions and diagrams render this book essential for the student and the experimenter, as well as the design professional.Simplified Design of Switching Power Supplies concentrates on the use of IC regulators. All popular forms of switching supplies, including DC-DC converters, inverters, buck, boost, buck-boost, pulse frequency modulation, pulse width modulation, current-mode control and pulse skipping, are described in detail. The design examples may
Electromagnetically induced absorption in a non-degenerate three-level ladder system
Whiting, Daniel J; Keaveney, James; Zentile, Mark A; Adams, Charles S; Hughes, Ifan G
2015-01-01
We investigate, theoretically and experimentally, the transmission of light through a thermal vapour of three-level ladder-type atoms, in the presence of 2 counter-propagating control fields. A simple theoretical model predicts the presence of electromagnetically induced absorption (EIA) in this pure three-level system when the control field is resonant. Experimentally, we use $^{87}$Rb in a large magnetic field of 0.62~T to reach the hyperfine Paschen-Back regime and realise a non-degenerate three-level system. Experimental observations verify the predictions over a wide range of detunings.
Schemes for Probabilistic Teleportation of an Unknown Three-Particle Three-Level Entangled State
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
In this paper, two schemes for teleporting an unknown three-particle three-level entangled state are proposed. In the first scheme, two partial three-particle three-level entangled states are used as the quantum channels, while in the second scheme, three two-particle three-level non-maximally entangled states are employed as quantum channels.It is shown that the teleportation can be successfully realized with certain probability, for both two schemes, if a receiver adopts some appropriate unitary transformations. It is shown also that the successful probabilities of these two schemes are different.
Preparation of inverted medium and processing in the inverted medium
Energy Technology Data Exchange (ETDEWEB)
Zafarullah, Ijaz [Department of Physics, Montana State University, Bozeman, MT 59717 (United States)]. E-mail: ijaz@montana.edu; Tian Minghzen [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Chang Tiejun [The Spectrum Laboratory, Montana State University, Bozeman, MT 59717 (United States); Randall Babbitt, W. [Department of Physics, Montana State University, Bozeman, MT 59717 (United States)
2007-11-15
The processing of weak optical signals in spatial-spectral holographic (SSH) materials coherently inverted with optical frequency chirped pulses were investigated. Simulations and experimental studies in Tm{sup 3+}:YAG were conducted to characterize the parameters of the frequency chirped laser pulse used to invert the SSH material in order to obtain high photon echo efficiency for SSH lidar processing. Collinear and angled beam geometries and single shot and accumulated processes were investigated. Echo efficiencies as high as 450% were measured, significantly higher than the typical stimulated photon echo efficiency of 10%.
Accelerating development of advanced inverters :
Energy Technology Data Exchange (ETDEWEB)
Neely, Jason C.; Gonzalez, Sigifredo; Ropp, Michael; Schutz, Dustin
2013-11-01
The high penetration of utility interconnected photovoltaic (PV) systems is causing heightened concern over the effect that variable renewable generation will have on the electrical power system (EPS). These concerns have initiated the need to amend the utility interconnection standard to allow advanced inverter control functionalities that provide: (1) reactive power control for voltage support, (2) real power control for frequency support and (3) better tolerance of grid disturbances. These capabilities are aimed at minimizing the negative impact distributed PV systems may have on EPS voltage and frequency. Unfortunately, these advanced control functions may interfere with island detection schemes, and further development of advanced inverter functions requires a study of the effect of advanced functions on the efficacy of antiislanding schemes employed in industry. This report summarizes the analytical, simulation and experimental work to study interactions between advanced inverter functions and anti-islanding schemes being employed in distributed PV systems.
Reverse engineering of a Hamiltonian for a three-level system via the Rodrigues’ rotation formula
Kang, Yi-Hao; Huang, Bi-Hua; Lu, Pei-Min; Xia, Yan
2017-02-01
We propose a scheme to reversely construct a three-level Hamiltonian via the Rodrigues’ rotation formula and an auxiliary unitary transformation. The main goal of the scheme is designing feasible pulses to drive a three-level system to evolve rapidly from an arbitrary initial state to a desired final state. Numerical simulations demonstrate that the scheme is not only fast but also robust against the decoherence caused by fluctuations of control parameters and some dissipation factors. Besides, we apply the idea to implement a Hadamard gate in a three-level system, and the results show the present scheme is much faster compared with stimulated Raman adiabatic passage (STIRAP). Therefore, the scheme may be useful to find out an effective shortcut to the adiabatic passage in a three-level system.
Teruya, Daisuke; Masukawa, Shigeo; Iida, Shoji
We propose a novel inverter that can be operated either as a Current Source Inverter (CSI) or as a Voltage Source Inverter (VSI) by changing only the control signals. It is proper to apply it to the interconnecting system with renewal energy, such as photovoltaic cells or wind generation systems, to a grid. This inverter is usually operated as the CSI connected to the grid. Even if the energy source has a lower voltage than the grid, the energy can be supplied to the grid through the proposed inverter. The power factor can be briefly maintained at almost unity. When power supply from the grid is interrupted, the proposed circuit should be operated as the VSI in the stand-alone operation mode. In this way, the circuit can maintain a constant output voltage to the loads. In this paper, the proposed circuit configuration and the control schemes for both the CSI and the VSI are described. Further, the circuit characteristics for both are discussed experimentally.
Using a PFET To Commutate an SCR
Edwards, D. B.; Ripple, W. E.
1984-01-01
Accidental turn-on prevented. PFET diverts load current around SCR to prevent false SCR triggering from current and voltage switching transients. New circuit used in all types of single phase and polyphase inverters and in buck-boost-, and flyback regulators.
Advanced Modular Inverter Technology Development
Energy Technology Data Exchange (ETDEWEB)
Adam Szczepanek
2006-02-04
Electric and hybrid-electric vehicle systems require an inverter to convert the direct current (DC) output of the energy generation/storage system (engine, fuel cells, or batteries) to the alternating current (AC) that vehicle propulsion motors use. Vehicle support systems, such as lights and air conditioning, also use the inverter AC output. Distributed energy systems require an inverter to provide the high quality AC output that energy system customers demand. Today's inverters are expensive due to the cost of the power electronics components, and system designers must also tailor the inverter for individual applications. Thus, the benefits of mass production are not available, resulting in high initial procurement costs as well as high inverter maintenance and repair costs. Electricore, Inc. (www.electricore.org) a public good 501 (c) (3) not-for-profit advanced technology development consortium assembled a highly qualified team consisting of AeroVironment Inc. (www.aerovironment.com) and Delphi Automotive Systems LLC (Delphi), (www.delphi.com), as equal tiered technical leads, to develop an advanced, modular construction, inverter packaging technology that will offer a 30% cost reduction over conventional designs adding to the development of energy conversion technologies for crosscutting applications in the building, industry, transportation, and utility sectors. The proposed inverter allows for a reduction of weight and size of power electronics in the above-mentioned sectors and is scalable over the range of 15 to 500kW. The main objective of this program was to optimize existing AeroVironment inverter technology to improve power density, reliability and producibility as well as develop new topology to reduce line filter size. The newly developed inverter design will be used in automotive and distribution generation applications. In the first part of this program the high-density power stages were redesigned, optimized and fabricated. One of the main
Solar Charged Stand Alone Inverter
Directory of Open Access Journals (Sweden)
M.Vasugi
2014-07-01
Full Text Available This paper deals with solar powered stand alone inverter which converts the variable dc output of a photovoltaic solar panel into ac that can be fed to loads. Stand alone inverters are used in systems where the inverter get its energy from batteries charged by photo voltaic arrays. A charge controller limits the rate at which electric current is added to or drawn from electric batteries. This charge discharge controller is needed to prevent the battery from being overcharged or discharged thus prolonging its life. The charge/discharge control is necessary in order to achieve safety and increase the capacity of the battery. The project has been tested according its operational purposes. Maximum power rating of the experimented solar charge controller is 100W according battery capacities. Cost effective solar charge controller has been designed and implemented to have efficient system and much longer battery lifetime. The dc output is given to inverter and then it is supplied to loads. This method is very cheap and cost effective.
DEFF Research Database (Denmark)
Guo, Xiaoqiang; Cavalcanti, Marcelo C.; Farias, Alexandre M.;
2013-01-01
Modulation strategy is one of the most important issues for three-level neutral-point-clamped inverters in three-phase transformerless photovoltaic systems. A challenge for modulation is how to keep the common-mode voltages constant to reduce the leakage currents. A single-carrier modulation...
21 CFR 184.1859 - Invert sugar.
2010-04-01
... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Invert sugar. 184.1859 Section 184.1859 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1859 Invert sugar. (a) Invert sugar (CAS Reg. No. 8013-17-0) is an...
Single-electron differential-amplifier/inverter/non-inverter
Hung, K.-M.; Chen, C.-S.; Lin, T.-W.
2006-07-01
This work presents a single-electron differential amplifier (SEDA), inverter, and non-inverter based on the triple single-dopant quantum-dot (TSDQD) configuration, with new structures. The competition between the field-induced and confinement-related shifts in the wavefunction of the quantum dots yields a field-controllable spatial-displacement single-electron transistor. Deeper impurity levels in quantum dots promise a higher operating temperature and higher on/off current ratios. The I- V characteristics of the device, studied using the transfer Hamiltonian approach (THA), show that the ratio of on/off currents is >80 000 and the voltage gain is >4 eV/Ry, where V is the applied voltage.
Grid Integration of Single Stage Solar PV System using Three-level Voltage Source Converter
Hussain, Ikhlaq; Kandpal, Maulik; Singh, Bhim
2016-08-01
This paper presents a single stage solar PV (photovoltaic) grid integrated power generating system using a three level voltage source converter (VSC) operating at low switching frequency of 900 Hz with robust synchronizing phase locked loop (RS-PLL) based control algorithm. To track the maximum power from solar PV array, an incremental conductance algorithm is used and this maximum power is fed to the grid via three-level VSC. The use of single stage system with three level VSC offers the advantage of low switching losses and the operation at high voltages and high power which results in enhancement of power quality in the proposed system. Simulated results validate the design and control algorithm under steady state and dynamic conditions.
Dynamic Behavior of Lambda-Type Three-Level Atoms and Two-Mode Cavity Field
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
A system comprising of Lambda-type three-level atoms and the two-mode cavity field is considered in this paper. Under the adiabatical approximation and the large detuning condition, the effective Hamiltonian of the system in the interaction picture can be given out. If the two identical three-level atoms pass through the cavity in turn, the entangled state atoms can be generated. When the interaction time is taken to an appropriate value, the maximally entangled states are created. At the same time, the dynamic behaviors of the system are studied in detail.
A Component-Reduced Zero-Voltage Switching Three-Level DC-DC Converter
DEFF Research Database (Denmark)
Qin, Zian; Pang, Ying; Wang, Huai;
2016-01-01
The basic Zero-Voltage Switching (ZVS) three-level DC-DC converter has one clamping capacitor to realize the ZVS of the switches, and two clamping diodes to clamp the voltage of the clamping capacitor. In order to reduce the reverse recovery loss of the diode as well as its cost, this paper...... proposes to remove one of the clamping diodes in basic ZVS three-level DC-DC converter. With less components, the proposed converter can still have a stable clamping capacitor voltage, which is clamped at half of the dc link voltage. Moreover, the ZVS performance will be influenced by removing the clamping...
A Comparative analysis of three level VSC based multi-pulse STATCOM
Directory of Open Access Journals (Sweden)
Smruti Ranjan Barik
2014-07-01
Full Text Available This paper presents a comparative analysis among different models of three level NPC (Neutral point clamped VSC (Voltage source converter based STATCOMs. Here separate models of 12- pulse, 24-pulse, 36-pulse, 48-pulse VSC based STATCOMs are configured in MATLAB environment. These individual models are synthesized using appropriate number of three level converters which are switched at fundamental frequency and their gate pulse pattern are properly phase shifted to get desired number of pulses. The simulation results of each individual model are analyzed in three different modes: inductive, capacitive and floating mode. Harmonic content of the proposed higher pulse models are limited as per IEEE 519 standards.
Cascaded Multicell Trans-Z-Source Inverters
DEFF Research Database (Denmark)
Li, Ding; Chiang Loh, Poh; Zhu, Miao
2013-01-01
Inverters with high-output voltage gain usually face the problem of high-input current flowing through their components. The problem might further be exaggerated if the inverters use high-frequency magnetic devices like transformers or coupled inductors. Leakage inductances of these devices must....... Simulation and experimental results have shown that the multicell inverters can produce the same high-voltage gain, while keeping currents and voltages of the components low. The inverters can also step down their output voltages like a traditional voltage-source inverter without compromising waveform...
Advancement in solar PV Inverter
Directory of Open Access Journals (Sweden)
Devendra Doda
2012-09-01
Full Text Available This teardown article will delve into the architectural design and components of a solar inverter card starting from the Solar panel DC inputs and working through the DC to AC conversion process to the AC output that is sent out to the power grid. Features needed to be implemented into such a design to meet various safety and other performance standards as well as stringent power company demands upon the signal that is put onto their grid will be shown. In the process, major elements and component choices made in the design of the series of solar inverters, from the EMI suppression capacitors with a special emphasis on isolation and protection, through the smart use of optically isolated MOSFETgatedrivers.
Transformerless dc-Isolated Converter
Rippel, Wally E.
1987-01-01
Efficient voltage converter employs capacitive instead of transformer coupling to provide dc isolation. Offers buck/boost operation, minimal filtering, and low parts count, with possible application in photovoltaic power inverters, power supplies and battery charges. In photovoltaic inverter circuit with transformerless converter, Q2, Q3, Q4, and Q5 form line-commutated inverter. Switching losses and stresses nil because switching performed when current is zero.
Intensity correlations and anticorrelations in a three-level cascade system
Indian Academy of Sciences (India)
SHAIK AHMED; PREETHI N WASNIK; SUNEEL SINGH; P ANANTHA LAKSHMI
2016-12-01
We study the intensity–intensity correlations of the radiation emitted on probe transition in a three level cascade electromagnetically-induced transparency (EIT) scheme. Further, we show that by applying even a very weak incoherent pump, the nature of the emitted radiation can be switched from classical to non-classicalwithout significantly affecting the probe transparency
Integrated Differential Three-Level High-Voltage Pulser Output Stage for CMUTs
DEFF Research Database (Denmark)
Llimos Muntal, Pere; Larsen, Dennis Øland; Jørgensen, Ivan Harald Holger;
2015-01-01
A new integrated differential three-level highvoltage pulser output stage to drive capacitive micromachined ultrasonic transducers (CMUTs) is proposed in this paper. A topology comparison between the new differential output stage and the most commonly used single-ended topology is performed...
Radiation forces on a three-level atom in the high-order Bessel beams
Institute of Scientific and Technical Information of China (English)
Wang Zheng-Ling; Yin Jian-Ping
2008-01-01
The general expressions of the average dissipative and dipole forces acting on a A-configuration three-level atom in an arbitrary light field are derived by means of the optical Bloch equations based on the atomic density matrix elements, and the general properties of the average dissipative and dipole forces on a three-level atom in the linearly-polarized high-order Bessel beams (HBBs) are analysed. We find a resonant property (with two resonant peaks) of the dissipative force and a non-resonant property (with two pairs of non-resonant peaks) of the dipole force on the three-level atom, which are completely different from those on the two-level atom. Meanwhile we find a saturation effect of the average dissipative force in the HBB, which comes from the saturation of the upper-level population. Our study shows that the general expressions of the average dissipative and dipole forces on the three-level atom will be simplified to those of the two-level atom under the approximation of large detuning. Finally, we study the axial and azimuthal Doppler cooling of atoms in 1D optical molasses composed of two counter-propagating HBBs and discuss the azimuthal influence of the HBB on the Doppler cooling limit. We also find that the Doppler limit of atoms in the molasses HBB is slightly below the conventional Doppler limit of hг/(2кB) due to the orbital angular momentum lh of the HBB.
High-Speed Generation of Entangled States for Two Three-Level Atoms
Institute of Scientific and Technical Information of China (English)
ZHENG Shi-Biao
2007-01-01
A scheme is presented for generating entangled states for two three-level atoms in a cavity. In the scheme two atoms simultaneously interact with a cavity mode with a small detuning. Thus, the operation time is very short,which is important in view of decoherence.
Carrier-based modulation schemes for various three-level matrix converters
DEFF Research Database (Denmark)
Blaabjerg, Frede; Loh, P.C.; Rong, R.C.;
2008-01-01
Matrix converters with three-level phase switching and five-level line switching characteristics have recently been proposed as improved ldquoall semiconductorrdquo ac-ac power processors. For their control, different modulation schemes have also been developed with different researchers claiming...... be implemented on a single common hardware platform....
Kramers-Kronig relation in a Doppler-broadenedΛ-type three-level system
Institute of Scientific and Technical Information of China (English)
王梦; 庞兆广; 王如泉; 左战春; 芦小刚; 白金海; 裴丽娅; 缪兴绪; 高艳磊; 吴令安; 傅盘铭; 杨世平
2015-01-01
We measure the absorption and dispersion in a Doppler-broadenedΛ-type three level system by resonant stimulated Raman spectroscopy with homodyne detection. Through studying the dressed state energies of the system, it is found that the absorption and dispersion satisfy the Kramers–Kronig relation. The absorption and dispersion spectra calculated by employing this relation agree well with our experimental observations.
Why do we need three levels to understand the molecular optical response?
Perez-Moreno, Javier; Clays, Koen; Kuzyk, Mark G.
2011-10-01
Traditionally, the nonlinear optical response at the molecular level has been modeled using the two-level approximation, under the assumption that the behavior of the exact sum-over-states (SOS) expressions for the molecular polarizabilities is well represented by the contribution of only two levels. We show how, a rigorous application of the Thomas-Kuhn sum-rules over the SOS expression for the diagonal component of the first-hyperpolarziability proves that the two-level approximation is unphysical. In addition, we indicate how the contributions of potentially infinite number of states to the SOS expressions for the first-hyperpolarizability are well represented by the contributions of a generic three-level system. This explains why the analysis of the three-level model in conjugation with the sum rules has lead to successful paradigms for the optimization of organic chromophores.
Testing strong factorial invariance using three-level structural equation modeling.
Jak, Suzanne
2014-01-01
Within structural equation modeling, the most prevalent model to investigate measurement bias is the multigroup model. Equal factor loadings and intercepts across groups in a multigroup model represent strong factorial invariance (absence of measurement bias) across groups. Although this approach is possible in principle, it is hardly practical when the number of groups is large or when the group size is relatively small. Jak et al. (2013) showed how strong factorial invariance across large numbers of groups can be tested in a multilevel structural equation modeling framework, by treating group as a random instead of a fixed variable. In the present study, this model is extended for use with three-level data. The proposed method is illustrated with an investigation of strong factorial invariance across 156 school classes and 50 schools in a Dutch dyscalculia test, using three-level structural equation modeling.
Vacuum-Induced Quantum Interference in a Trapped ∧-Configuration Three-Level System
Institute of Scientific and Technical Information of China (English)
WANG Zheng-Ling; YIN Jian-Ping
2005-01-01
@@ In consideration of quantization of centre-of-mass motion, we derive the second-order solution of the dynamic equation of a ∧-configuration three-level atom confined in an approximately harmonic trap by using the timedependent perturbation theory. It is found that there are a series of dark lines in the second-order probability spectrum with multi-peak structures, which is the result of the quantum interference from the same vacuum mode in the spontaneous decay process of the trapped atom from the upper level to the two nearby lower levels. Our study shows that the second-order spectrum may be modified by the oscillation frequency Ω of the trap and the frequency difference △ between two lower levels of the three-level atom, and the depth of the dark lines from the vacuum-induced quantum interference effect is strongly dependent on the above two parameters (Ω and △).
A three-level framework for performance-based railway timetabling
DEFF Research Database (Denmark)
Goverde, Rob M P; Bešinović, Nikola; Binder, Anne
2016-01-01
The performance of railway operations depends highly on the quality of the railway timetable. In particular for dense railway networks it can be challenging to obtain a stable robust conflict-free and energy-efficient timetable with acceptable infrastructure occupation and short journey times....... This paper presents a performance-based railway timetabling framework integrating timetable construction and evaluation on three levels: microscopic, macroscopic, and a corridor fine-tuning level, where each performance indicator is optimized or evaluated at the appropriate level. A modular implementation...... of the three-level framework is presented and demonstrated on a case study on the Dutch railway network illustrating the feasibility of this approach to achieve the highest timetabling design level....
Testing strong factorial invariance using three-level structural equation modeling
Directory of Open Access Journals (Sweden)
Suzanne eJak
2014-07-01
Full Text Available Within structural equation modeling, the most prevalent model to investigate measurement bias is the multigroup model. Equal factor loadings and intercepts across groups in a multigroup model represent strong factorial invariance (absence of measurement bias across groups. Although this approach is possible in principle, it is hardly practical when the number of groups is large or when the group size is relatively small. Jak, Oort and Dolan (2013 showed how strong factorial invariance across large numbers of groups can be tested in a multilevel structural equation modeling framework, by treating group as a random instead of a fixed variable. In the present study, this model is extended for use with three-level data. The proposed method is illustrated with an investigation of strong factorial invariance across 156 school classes and 50 schools in a Dutch dyscalculia test, using three-level structural equation modeling.
Some studies of the interaction between N-two level atoms and three level atom
Directory of Open Access Journals (Sweden)
D.A.M. Abo-Kahla
2016-07-01
Full Text Available In this paper, we present the analytical solution for the model that describes the interaction between a three level atom and two systems of N-two level atoms. The effect of the quantum numbers on the atomic inversion and the purity, for some special cases of the initial states, are investigated. We observe that the atomic inversion and the purity change remarkably by the change of the quantum numbers.
Nonlinear Theory of Light Speed Reduction in a Three-Level A System
Institute of Scientific and Technical Information of China (English)
王德重; 李代军; 刘夏姬; 李师群; 王育竹
2001-01-01
We present a nonlinear theory of light velocity reduction in a three-level A system based on electromagneticllyinduced transparency. Analysis shows that the probe field propagates with a velocity that is quite strongly dependent on its intensity instead of being merely approximately dependent on the coupling intensity. Moreover,the minimum group velocity of the probe field is analytically given for a given input power.
Goos-Hanchen-like shift of three-level matter wave incident on Raman beams
Duan, Zhenglu; Hu, Liyun; Xu, XueXiang; Liu, Cunjin
2013-01-01
When a three-level atomic wavepacket is obliquely incident on a "edium slab" consisting of two far-detuned laser beams, there exists lateral shift between reflection and incident points at the surface of a "medium slab", analogous to optical Goos-Hanchen effect. We evaluate lateral shifts for reflected and transmitted waves via expansion of reflection and transmission coefficients, in contrast to the stationary phase method. Results show that lateral shifts can be either positive or negative ...
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
We propose a scheme for generating a maximally entangled state of two three-level superconducting quantum interference devices (SQUIDs) by using a quantized cavity field and classical microwave pluses in cavity. In this scheme, no quantum information will be transferred from the SQUIDs to the cavity since the cavity field is only virtually excited. Thus, the cavity decay is suppressed during the entanglement generation.
Entanglement and coherence of a three-level atom in Λ configuration interacting with two fields
Institute of Scientific and Technical Information of China (English)
Zhang Jian-Song; Xu Jing-Bo
2009-01-01
We investigate the entanglement of a three-level atom in A configuration interacting with two quantized field modes by using logarithmic negativity. Then, we study the relationship of the atomic coherence and the entanglement between two fields which are initially prepared in vacuum or thermal states. We find that if the two fields are prepared in thermal states, the atomic coherence can induce the entanglement between two thermal fields. However, there is no coherence-induced entanglement between two vacuum fields.
Gavryusev, V.; Signoles, A.; Ferreira-Cao, M.; Zürn, G.; Hofmann, C. S.; Günter, G.; Schempp, H.; Robert-de-Saint-Vincent, M.; Whitlock, S.; Weidemüller, M.
2016-08-01
We present combined measurements of the spatially resolved optical spectrum and the total excited-atom number in an ultracold gas of three-level atoms under electromagnetically induced transparency conditions involving high-lying Rydberg states. The observed optical transmission of a weak probe laser at the center of the coupling region exhibits a double peaked spectrum as a function of detuning, while the Rydberg atom number shows a comparatively narrow single resonance. By imaging the transmitted light onto a charge-coupled-device camera, we record hundreds of spectra in parallel, which are used to map out the spatial profile of Rabi frequencies of the coupling laser. Using all the information available we can reconstruct the full one-body density matrix of the three-level system, which provides the optical susceptibility and the Rydberg density as a function of spatial position. These results help elucidate the connection between three-level interference phenomena, including the interplay of matter and light degrees of freedom and will facilitate new studies of many-body effects in optically driven Rydberg gases.
Gavryusev, V; Ferreira-Cao, M; Zürn, G; Hofmann, C S; Günter, G; Schempp, H; Robert-de-Saint-Vincent, M; Whitlock, S; Weidemüller, M
2016-01-01
We present combined measurements of the spatially-resolved optical spectrum and the total excited-atom number in an ultracold gas of three-level atoms under electromagnetically induced transparency conditions involving high-lying Rydberg states. The observed optical transmission of a weak probe laser at the center of the coupling region exhibits a double peaked spectrum as a function of detuning, whilst the Rydberg atom number shows a comparatively narrow single resonance. By imaging the transmitted light onto a charge-coupled-device camera, we record hundreds of spectra in parallel, which are used to map out the spatial profile of Rabi frequencies of the coupling laser. Using all the information available we can reconstruct the full one-body density matrix of the three-level system, which provides the optical susceptibility and the Rydberg density as a function of spatial position. These results help elucidate the connection between three-level interference phenomena, including the interplay of matter and li...
Multilevel Inverters for Electric Vehicle Applications
Energy Technology Data Exchange (ETDEWEB)
Habetler, T.G.; Peng, F.Z.; Tolbert, L.M.
1998-10-22
This paper presents multilevel inverters as an application for all-electric vehicle (EV) and hybrid-electric vehicle (HEV) motor drives. Diode-clamped inverters and cascaded H-bridge inverters, (1) can generate near-sinusoidal voltages with only fundamental frequency switching; (2) have almost no electromagnetic interference (EMI) and common-mode voltage; and (3) make an EV more accessible/safer and open wiring possible for most of an EV'S power system. This paper explores the benefits and discusses control schemes of the cascade inverter for use as an EV motor drive or a parallel HEV drive and the diode-clamped inverter as a series HEV motor drive. Analytical, simulated, and experimental results show the superiority of these multilevel inverters for this new niche.
Selection of Carrier Waveforms for PWM Inverter
Institute of Scientific and Technical Information of China (English)
陈国呈; 屈克庆; 许春雨; 孙承波
2003-01-01
In this paper the influence of different carrier waveforms upon the output characteristics of PWM inverter is described in detail. When a triangular carrier waveform is used in hard-switching PWM inverters, harmonics exist in the neighborhood of the output frequency of the inverter output voltage and current due to the dead time. The triangular carrier waveform used in soft-switching PWM inverter will cause difficulties in controlling resonance-trigger time, higher loss in the resonant circuit, and less utilization of the DC bus voltage. If a sawtooth carrier is used in hard-switching PWM inverter, there will be severe distortion in the current waveform. When sawtooth carriers with alternate positive and negative slopes are used in soft-switching PWM inverters, the resonancetrigger time is easy to control, and distortion in the output voltage and current caused by the dead time will not appear.
Cascaded trans-z-source inverters
DEFF Research Database (Denmark)
Li, Ding; Loh, Poh Chiang; Zhu, Miao;
2011-01-01
Z-source inverter is a recently proposed single-stage inverter with added voltage-boost capability for complementing the usual voltage-buck operation of a traditional voltage-source inverter. As long as the transformer element added in to the z-source concept, a trans-z-source inverter with one...... transformer and one capacitor is reported recently. This paper has adapted the cascaded concept into the trans-z-source and trans-quasi-z-source inverters to extend each to the cascaded topologies before combination is made with allowing more sources embedded which reduces the capacitor voltage and enhanced...... the compatibility for distributed sources. Unlike existing techniques, voltage stresses within the proposed inverters are better distributed among the passive components. Theoretical analysis for explaining these operating features has already been discussed before simulation were performed and an experimental...
Inverting the central limit theorem
Navascues, Miguel; Villanueva, Ignacio
2011-01-01
The central limit theorem states that the sum of N independently distributed n-tuples of real variables (subject to appropriate normalization) tends to a multivariate gaussian distribution for large N. Here we propose to invert this argument: given a set of n correlated gaussian variables, we try to infer information about the structure of the discrete microscopic probability distributions whose convolution generated such a macroscopic behavior. The techniques developed along the article are applied to prove that the classical description of certain macroscopic optical experiments is infinitely more complex than the quantum one.
Thirteen-level inverter for photovoltaic applications
Directory of Open Access Journals (Sweden)
Lasanthika Dissawa
2016-03-01
Full Text Available With the recent cost reduction and efficiency improvement of solar photovoltaic (PV cells, there is a growing interest towards PV systems in different applications. One promising application is solar PV powered electric vehicles. When they are moving on roads, the whole or some parts of the PV system might be shaded by trees, high buildings, etc.; which result in non-uniform insolation conditions. As a remedial measure, this paper presents a development of a cascaded multi-level inverter based PV system for electric vehicle applications. The basic architecture and switching of the converter switches are described. A laboratory prototype of the proposed architecture was implemented using MOSFETs and harmonic performance under different shading conditions was evaluated. It was found, that under shaded conditions, the 3rd harmonic content can increase and that it depends on the number of modules shaded and the loading condition. The shading performance, losses and power utilization of the cascaded multi-level inverter are compared with that of a conventional Pulse Width Modulated (PWM inverter architecture. The proposed inverter shows better immunity for shading than a PWM inverter. Furthermore, it was found that the switching losses of the proposed inverter are one 10th to one 20th of that of a PWM inverter. Additionally, by properly selecting the switches, it is also possible to reduce the conduction losses compared to that of a PWM inverter. Even though the power utilization is compromised at full insolation, the power utilization performance of the proposed inverter is superior under shading conditions, thus ideally suited for the selected application. As the modular nature of the proposed inverter allows cascading of more H-bridges with fewer cells, the harmonic, shading, loss and power utilization performance of the proposed inverter can be enhanced with more number of steps in the output waveform.
A coordination theoretic model for three level supply chains using contracts
Indian Academy of Sciences (India)
Arshinder; Arun Kanda; S G Deshmukh
2009-10-01
Typically, supply chain members are dependent on each other to manage various resources and information. The conﬂicting objectives and lack of coordination between supply chain members may often cause uncertainties in supply and demand. The basic elements of coordination theory like interdependency, coherency and mutuality may help in effective ﬂow of information and material between the dependent supply chain members. Supply chain contract can be an effective coordination mechanism to motivate all the members to be a part of the entire supply chain. There are different types of supply chain contracts such as buy back and quantity ﬂexibility contracts. Supply chain performance may be substantially improved by properly designing the contracts to share risks and rewards. The objective of this paper is to explore the applicability of coordination elements through an analytical model in three-level (Manufacturer–distributor–retailer) serial supply chains using contracts. The model evaluates the impact of supply chain contracts on various performance measures. The impact of some contract may be on some speciﬁc performance measure only, which helps managers to choose the type of contract if there is an objective of improving certain performance measure before hand. In three-level supply chains, the contracts are designed at two distinct interfaces: Manufacturer–distributor and distributor–retailer. The model demonstrates the complexity in evaluating the decision variables of three level supply chains. The proposed model is a novel approach to apply coordination theory at various levels of supply chain. The model also presents how the coordination elements are related to each other in various coordination cases.
Cooling and trapping of three-level atoms in a bichromatic standing wave
Pu, H.; Cai, T.; Bigelow, N. P.; Grove, T. T.; Gould, P. L.
1995-02-01
We show that a three-level atom in the cascade configuration can be stably trapped and cooled in one dimension by an intense bichromatic standing wave. At the two-photon resonance, rectified dipole forces result in a deep potential well which can be used to localize the atoms in space. In the vicinity of the rectified potential minimum, the spatial dependence of the dressed state energies can lead to a velocity dependence of the force which produces damping of the atomic motion. Consideration of the heating effects of momentum diffusion indicates that cooling and stable trapping at low temperatures is possible in such a bichromatic field.
Observation of three-level rectified dipole forces acting on trapped atoms
Grove, T. T.; Duncan, B. C.; Sanchez-Villicana, V.; Gould, P. L.
1995-06-01
We have observed rectified dipole forces acting on three-level atoms in the cascade configuration. Laser cooled and trapped rubidium atoms are illuminated with an intense bichromatic standing wave (780 and 776 nm) tuned near resonance with the 5S1/2-->5P3/2-->5D5/2 transitions. The resulting rectified forces produce periodic potential wells (71-μm period), which localize the cold atoms. Experimental results are in reasonable agreement with theoretical predictions. These forces may be useful in atom optics and laser traps.
THE CONSTRUCTIONS OF ALMOST BINARY SEQUENCE PAIRS WITH THREE-LEVEL CORRELATION BASED ON CYCLOTOMY
Institute of Scientific and Technical Information of China (English)
Peng Xiuping; Xu Chengqian
2012-01-01
In this paper,a new class of almost binary sequence pair with a single zero element is presented.The almost binary sequence pairs with three-level correlation are constructed based on cyclotomic numbers of order 2,4,and 6.Most of them have good correlation and balance property,whose maximum nontrivial correlation magnitudes are 2 and the difference between the numbers of occurrence of +1's and -1's are 0 or 1.In addition,the corresponding binary sequence pairs are investigated as well and we can also get some kinds of binary sequence pairs with optimum balance and good correlation.
Coherent Phase Control of Ultrafast Polarization Beats in Reverse V-Type Three-Level System
Institute of Scientific and Technical Information of China (English)
LI Ling; NIE Zhi-Qiang; JIANG Tong; ZHANG Yan-Peng; LI Pei-Zhe; GAN Chen-Li; SONG Jian-Ping; LI Yuan-Yuan
2007-01-01
We investigate the third-order nonlinear absorption and dispersion of femto- and atto-second polarization beats between the one-photon degenerate four-wave mixing process and the two-photon nondegenerate four-wave mixing process in the pure homogeneously-broadened reverse V-three-level using twin noisy Gelds. The third-order nonlinear response can be controlled and modified by the colour-locked correlation of twin noisy fields. Most importantly, the coherent phase control in optical heterodyne detection for studying the phase dispersion of the third-order susceptibility is demonstrated. The radiation-matter detuning oscillation is also considered in the frequency domain.
Realization of a holonomic quantum computer in a chain of three-level systems
Energy Technology Data Exchange (ETDEWEB)
Gürkan, Zeynep Nilhan, E-mail: nilhan.gurkan@gediz.edu.tr [Department of Industrial Engineering, Gediz University, Seyrek, 35665 Menemen, Izmir (Turkey); Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, 117543 Singapore (Singapore); Sjöqvist, Erik, E-mail: erik.sjoqvist@kemi.uu.se [Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala (Sweden); Department of Quantum Chemistry, Uppsala University, Box 518, SE-751 20 Uppsala (Sweden)
2015-12-18
Holonomic quantum computation is the idea to use non-Abelian geometric phases to implement universal quantum gates that are robust to fluctuations in control parameters. Here, we propose a compact design for a holonomic quantum computer based on coupled three-level systems. The scheme does not require adiabatic evolution and can be implemented in arrays of atoms or ions trapped in tailored standing wave potentials. - Highlights: • We develop a novel scheme for universal holonomic quantum computation. • The scheme involves non-Abelian geometric phases in a spin-chain. • The resources scale linearly with the number of logical qubits. • The scheme does not require adiabatic evolution.
Exact solution to laser rate equations: three-level laser as a Morse-like oscillator
León-Montiel, R. de J.; Moya-Cessa, Héctor M.
2016-08-01
It is shown how the rate equations that model a three-level laser can be cast into a single second-order differential equation, whose form describes a time-dependent harmonic oscillator. Using this result, we demonstrate that the resulting equation can be identified as a Schrödinger equation for a Morse-like potential, thus allowing us to derive exact closed-form expressions for the dynamics of the number of photons inside the laser cavity, as well as the atomic population inversion.
Single molecule photon emission statistics of driven three-level systems.
Peng, Yonggang; Zheng, Yujun; Brown, Frank L H
2007-03-14
We study the statistics of photon emission from three-level single molecule systems. The generating function method [Y. Zheng and F. L. H. Brown, Phys. Rev. Lett. 90, 238305 (2003)] is used to calculate steady state absorption line shapes and Mandel's Q parameter as a function of excitation frequency, as well as the time dependence associated with approach to the steady state. The line shape calculations confirm known results derived via other methods, while the Q parameter results display complex frequency dependences not amenable to simple interpretation. This study confirms the applicability of the generating function formalism to multilevel quantum systems, including the proper modeling of quantum coherence effects.
Coherent control of a V-type three-level system in a single quantum dot.
Wang, Q Q; Muller, A; Cheng, M T; Zhou, H J; Bianucci, P; Shih, C K
2005-10-28
In a semiconductor quantum dot, the IIx and IIy transitions to the polarization eigenstates, |x> and |y>, naturally form a three-level V-type system. Using low-temperature polarized photoluminescence spectroscopy, we have investigated the exciton dynamics arising under strong laser excitation. We also explicitly solved the density matrix equations for comparison with the experimental data. The polarization of the exciting field controls the coupling between the otherwise orthogonal states. In particular, when the system is initialized into \\Y>, a polarization-tailored pulse can swap the population into |x>, and vice versa, effectively operating on the exciton spin.
Kramers-Kronig relation in a Doppler-broadened Λ-type three-level system
Wang, Meng; Lu, Xiao-Gang; Bai, Jin-Hai; Pei, Li-Ya; Miao, Xing-Xu; Gao, Yan-Lei; Wu, Ling-An; Fu, Pan-Ming; Yang, Shi-Ping; Pang, Zhao-Guang; Wang, Ru-Quan; Zuo, Zhan-Chun
2015-11-01
We measure the absorption and dispersion in a Doppler-broadened Λ-type three level system by resonant stimulated Raman spectroscopy with homodyne detection. Through studying the dressed state energies of the system, it is found that the absorption and dispersion satisfy the Kramers-Kronig relation. The absorption and dispersion spectra calculated by employing this relation agree well with our experimental observations. Project supported by the National Basic Research Program of China (Grant Nos. 2013CB922002 and 2010CB922904), the National Natural Science Foundation of China (Grant Nos. 11274376 and 61308011), and the Natural Science Foundation of Hebei Province, China (Grant No. A2015205161).
Controlling Single-Photon Transport along an Optical Waveguide by using a Three-Level Atom
Institute of Scientific and Technical Information of China (English)
TIAN Wei; CHEN Bin; XU Wei-Dong
2012-01-01
We theoretically investigate the single-photon transport properties in an optical waveguide embedded with a V-type three-level atom (VTLA) based on symmetric and asymmetric couplings between the photon and the VTLA.Our numerical results show that the transmission spectrum of the incident photon can be well controlled by virtue of both symmetric and asymmetric coupling interactions.A multifrequency photon attenuator is realized by controlling the asymmetric coupling interactions.Furthermore,the influences of dissipation of the VTLA for the realistic physical system on single-photon transport properties are also analyzed.
Detecting non-Abelian geometric phases with three-level {Lambda} systems
Energy Technology Data Exchange (ETDEWEB)
Du Yanxiong; Xue Zhengyuan; Zhang Xinding; Yan Hui [Laboratory of Quantum Information Technology, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006 (China)
2011-09-15
We show that a non-Abelian gauge potential in two nearly degenerated dressed states may be induced by two laser beams interacting with a three-level {Lambda} atomic system. We demonstrate that the populations of the atomic states at the end of a composed path formed by two closed loops are dependent on the order of those two loops, showing an unambiguous signature of the non-Abelian geometric phase. Through numerical calculations, we show that the non-Abelian feature of the geometric phases can be tested under realistic conditions.
Coherent Phase Control of Multiphoton Ionization in Three-Level Ladder-Type System
Institute of Scientific and Technical Information of China (English)
ZHANG Shi-An; CHEN Yu-Ting; WANG Zu-Geng; SUN Zhen-Rong
2009-01-01
We present the theoretical investigation of photoelectron spectroscopy resulting from the strong field induced multiphoton ionization in a typical three-level ladder-style system.Our theoretical results show that the photoelectron spectral structure can be alternatively steered by spectral phase modulation.This physical mechanism for strong field quantum control is explicitly exploited by the time-dependent dressed state population.It is concluded that the phase-shaped laser pulses can be used to selectively manipulate the multiphoton ionization process in complicated quantum systems.
A new interleaved double-input three-level boost converter
DEFF Research Database (Denmark)
Chen, Jianfei; Hou, Shiying; Sun, Tao
2016-01-01
. The operating principle of the DITLB converter under the individual supplying power (ISP) and simultaneous supplying power (SSP) mode is analyzed. In addition, closed-loop control strategies composed of a voltage-current loop and a voltage-balance loop, have been researched to make the converter operate......This paper proposes a new interleaved double-input three-level Boost (DITLB) converter, which is composed of two boost converters indirectly in series. Thus, a high voltage gain, together with a low component stress and a small input current ripple due to the interleaved control scheme, is achieved...
Emission Probability of the Cascade Three-Level-Atom Mazer with Injected Atomic Coherence
Institute of Scientific and Technical Information of China (English)
熊锦; 张智明
2002-01-01
We investigate the effects of the injected atomic coherence on the atomic emission probability of the micromaser injected with ultracold cascade three-level atoms by considering that the atoms are initially in the coherent superposition states of the two upper levels. We show that there is no interference between the transitions from the two upper levels to the lowest level. In the large atom-field-detuning case, the atomic emission probability decreases as the coherent parameter increases. In the zero atom-field-detuning case, the atomic emission probability has three sets of resonance peaks. The reason for these results has been explained.
Radiotherapy for inverted papilloma: a case report
Energy Technology Data Exchange (ETDEWEB)
Levendag, P.C.; Annyas, A.A.; Escajadillo, J.R.; Elema, J.D. (Rijksuniversiteit Groningen (Netherlands). Academisch Ziekenhuis)
1984-06-01
Inverted papilloma is an infrequent tumour of the nasal cavity and paranasal sinuses associated with controversy. The incidence of carcinoma in situ associated with inverted papilloma, has not been very well documented until now. Therefore the authors present a case report characterized by an aggressive clinical behaviour, treated by extensive surgery and ultimately controlled by radiotherapy.
Radiotherapy for inverted papilloma: a case report.
Levendag, P C; Annyas, A A; Escajadillo, J R; Elema, J D
1984-06-01
Inverted papilloma is an infrequent tumour of the nasal cavity and paranasal sinuses associated with controversy. The incidence of carcinoma in situ associated with inverted papilloma, has not been very well documented until now. Therefore, we present a case report characterized by an aggressive clinical behaviour, treated by extensive surgery and ultimately controlled by radiotherapy.
On Invertible Sampling and Adaptive Security
DEFF Research Database (Denmark)
Ishai, Yuval; Kumarasubramanian, Abishek; Orlandi, Claudio
2011-01-01
sampling algorithm A, obtain another sampling algorithm B such that the output of B is computationally indistinguishable from the output of A, but B can be efficiently inverted (even if A cannot). This invertible sampling problem is independently motivated by other cryptographic applications. We show...
Circuit controls transients in SCR inverters
Moore, E. T.; Wilson, T. G.
1964-01-01
Elimination of starting difficulties in SCR inverters is accomplished by the addition of two taps of the output winding of the inverter. On starting or under transient loads, the two additional taps deliver power through diodes without requiring quenching of SCR currents in excess of normal starting load.
Characterization of interface traps on MOS transistor submicronic by the three level charge pumping
Sellami, M.; Bouchemat, M.; Kahouadji, M.; Djahli, F.
2005-05-01
Because of its efficiency, its high precision and its easy use regarding to classical techniques of Si-Sio2 (C-V, DLTS, Conductanceldots), interface characterization, the charge pumping technique has seen a large evolution these years. Many improvements have been made other, derivation techniques have been developed (at three-level charge pumping, spectroscopic charge pumping ldots) This technique is particularly used for very slight geometry MOS transistors damaging, where other techniques have no utility. This damaging often leads to the creation of a fixed trapped charge in the oxide coat and active electronically defaults in the oxide Semi-conductor interface after the application of ageing constraint (ionizing radiation, injection carrier). This ageing is so pronounced when the dimensions are slight this represents the main obstacle that the microelectronics must face. In this article we simulate the three-level charge pumping technique with SPICE3F4 simulator. This simulation will permit the obtaining of spatial and energetic spread of defaults at the interface.
B-MIC: An Ultrafast Three-Level Parallel Sequence Aligner Using MIC.
Cui, Yingbo; Liao, Xiangke; Zhu, Xiaoqian; Wang, Bingqiang; Peng, Shaoliang
2016-03-01
Sequence alignment is the central process for sequence analysis, where mapping raw sequencing data to reference genome. The large amount of data generated by NGS is far beyond the process capabilities of existing alignment tools. Consequently, sequence alignment becomes the bottleneck of sequence analysis. Intensive computing power is required to address this challenge. Intel recently announced the MIC coprocessor, which can provide massive computing power. The Tianhe-2 is the world's fastest supercomputer now equipped with three MIC coprocessors each compute node. A key feature of sequence alignment is that different reads are independent. Considering this property, we proposed a MIC-oriented three-level parallelization strategy to speed up BWA, a widely used sequence alignment tool, and developed our ultrafast parallel sequence aligner: B-MIC. B-MIC contains three levels of parallelization: firstly, parallelization of data IO and reads alignment by a three-stage parallel pipeline; secondly, parallelization enabled by MIC coprocessor technology; thirdly, inter-node parallelization implemented by MPI. In this paper, we demonstrate that B-MIC outperforms BWA by a combination of those techniques using Inspur NF5280M server and the Tianhe-2 supercomputer. To the best of our knowledge, B-MIC is the first sequence alignment tool to run on Intel MIC and it can achieve more than fivefold speedup over the original BWA while maintaining the alignment precision.
Directory of Open Access Journals (Sweden)
Amado González Moga
Full Text Available ABSTRACT Objective: To present the results of treatment of patients with cervical discopathy by anterior cervical approach, discectomy and placement of a PEEK interbody cage without anterior plate fixation. Methods: Retrospective, cross-sectional study from March 2013 to March 2015. Sixteen patients with radiculopathy or clinical signs of myelopathy were included; all patients underwent cervical surgery through anterior approach, discectomy, and placement of PEEK cages on three levels. Decompression levels were determined according to the correlation between preoperative radiological and clinical findings. Results: Sixteen patients predominantly male were included, with mean age of 50 years at the onset of the condition. Ten patients had involvement of C4-C5, C5-C6, C6-C7 levels, and six patients C3-C4, C4-C5 and C5-C6. Fourteen patients had cervicobrachialgia and two myelopathy. The preoperative visual analog scale average was 8/10 and the average postoperative value at 6 months was 3/10. At 6 months, there was no radiological evidence of recurrence. One patient had non-fatal complications. Conclusions: The treatment of cervical discopathy by anterior approach with interbody fusion with PEEK cage on three levels, with no plate fixation seemed to be safe and effective with better long-term results in terms of pain and myelopathy. The clinical results compare favorably with other similar series and, most importantly, the complications associated with anterior fixation plate are avoided.
Fully robust qubit in atomic and molecular three-level systems
Aharon, N.; Cohen, I.; Jelezko, F.; Retzker, A.
2016-12-01
We present a new method of constructing a fully robust qubit in a three-level system. By the application of continuous driving fields, robustness to both external and controller noise is achieved. Specifically, magnetic noise and power fluctuations do not operate within the robust qubit subspace. Whereas all the continuous driving based constructions of such a fully robust qubit considered so far have required at least four levels, we show that in fact only three levels are necessary. This paves the way for simple constructions of a fully robust qubit in many atomic and solid state systems that are controlled by either microwave or optical fields. We focus on the NV-center in diamond and analyze the implementation of the scheme, by utilizing the electronic spin sub-levels of its ground state. In current state-of-the-art experimental setups the scheme leads to improvement of more than two orders of magnitude in coherence time, pushing it towards the lifetime limit. We show how the fully robust qubit can be used to implement quantum sensing, and in particular, the sensing of high frequency signals.
Multilevel Inverter by Cascading Industrial VSI
DEFF Research Database (Denmark)
Teodorescu, Remus; Blaabjerg, Frede; Pedersen, John Kim
2002-01-01
In this paper the modularity concept applied to medium-voltage adjustable speed drives is addressed. First, the single-phase cascaded voltage-source inverter that uses series connection of IGBT H-bridge modules with isolated dc-buses is presented. Next, a novel three-phase cascaded voltage...... of the motor rated kVA. The concept of using cascaded inverters is further extended to a new modular motor-modular inverter system where the motor winding connections are reconnected into several three-phase groups, either six-lead or 12-lead connection according to the voltage level, each powered...... by a standard triphase IGBT inverter module. Thus, a high fault tolerance is being achieved and the output transformer requirement is eliminated. A staggered space-vector modulation technique applicable to three-phase cascaded voltage-source inverter topologies is also demonstrated. Both computer simulations...
Leakage current measurement in transformerless PV inverters
DEFF Research Database (Denmark)
Kerekes, Tamas; Sera, Dezso; Mathe, Laszlo
2012-01-01
to be used in commercial PV inverters for the measurement of leakage and fault ground currents. The German VDE0126–1–1 standard gives the limit for fault and leakage ground currents and all grid connected PV inverters have to comply with these limits and disconnect from the grid in case of a fault.......Photovoltaic (PV) installations have seen a huge increase during the last couple of years. Transformerless PV inverters are gaining more share of the total inverter market, due to their high conversion efficiency, small weight and size. Nevertheless safety should have an important role in case...... of these tranformerless systems, due to the missing galvanic isolation. Leakage and fault current measurement is a key issue for these inverter topologies to be able to comply with the required safety standards. This article presents the test results of two different current measurement sensors that were suggested...
DEFF Research Database (Denmark)
Choi, Uimin; Blaabjerg, Frede; Lee, Kyo-Beum
2014-01-01
To improve the efficiency of the photovoltaic (PV) system, the centralized topology using three-level inverters are widely used. In this system, PV modules are separately connected to the split DC-links. This causes a decrease of maximum power point tracking (MPPT) efficiency under the partial...
A high-resolution time-to-digital converter using a three-level resolution
Dehghani, Asma; Saneei, Mohsen; Mahani, Ali
2016-08-01
In this article, a three-level resolution Vernier delay line time-to-digital converter (TDC) was proposed. The proposed TDC core was based on the pseudo-differential digital architecture that made it insensitive to nMOS and pMOS transistor mismatches. It also employed a Vernier delay line (VDL) in conjunction with an asynchronous read-out circuitry. The time interval resolution was equal to the difference of delay between buffers of upper and lower chains. Then, via the extra chain included in the lower delay line, resolution was controlled and power consumption was reduced. This method led to high resolution and low power consumption. The measurement results of TDC showed a resolution of 4.5 ps, 12-bit output dynamic range, and integral nonlinearity of 1.5 least significant bits. This TDC achieved the consumption of 68.43 µW from 1.1-V supply.
Berry phases in the three-level atoms driven by quantized light fields
Indian Academy of Sciences (India)
Mai-Lin Liang; Zong-Cheng Xu; Bing Yuan
2008-03-01
A theoretical analysis of Berry's phases is given for the three-level atoms interacting with external one-mode and two-mode quantized light fields. Three main results are obtained: (i) There is a Berry phase which vanishes in the classical limit or this Berry phase is completely induced by the field quantization; (ii) Berry's phases for the one-mode field and the two-mode field can be equal so long as the photon numbers of the two-mode field are properly chosen; (iii) In the two-mode case, Berry phases of the atom interacting with one mode is affected by the other mode even if the photon number of the other mode is zero.
Negative and positive hysteresis in double-cavity optical bistability in three-level atom
Babu, H Aswath
2010-01-01
We present novel hysteretic behaviour of a three-level ladder atomic system exhibiting double-cavity optical bistability in the mean-field limit. The two fields coupling the atomic system experience feedback via two independent, unidirectional, single mode ring cavities and exhibit cooperative phenomena, simultaneously. The system displays a range of rich dynamical features varying from normal switching to self pulsing and a period-doubling route to chaos for both the fields. We focus our attention to a new hump like feature in the bistable curve arising purely due to cavity induced inversion, which eventually leads to negative hysteresis in the bistable response. This is probably the only all-optical bistable system that exhibits positive as well as negative bistable hysteresis in different input field intensity regimes. For both the fields, the switching times, the associated critical slowing down, the self-pulsing characteristics, and the chaotic behaviour can be controlled to a fair degree, moreover, all ...
Optimal Control of Population Transfer in Three-Level A System with Genetic Algorithms
Institute of Scientific and Technical Information of China (English)
ZHANG Xiang-Yun; SUN Zhen-Rong; CHEN Guo-Liang; WANG Zu-Geng; XU Zhi-Zhan; LI Ru-Xin
2004-01-01
Population transfer in a three-level A system is simulated numerically and optimized. Almost complete population transfer from |1〉 to |3〉 is achieved by a genetic algorithm while the population in state |2〉 reached minimum over the entire evolution at the same time. The result shows that the optimal pulse sequence is the well-known stimulated Raman adiabatic passage (STIRAP) scheme. The detuning of pump pulse and Stokes pulse △p and △s with the opposite sign and the chirps χp and χs with the same sign are in favour of the complete and robust population transfer for few-cycle laser pulse. Rabi frequencies Ωp and Ωs have insensitive effects on the complete population transfer during a large scope of their ratio when they are large enough.
Goos-Hänchen-like shift of three-level matter wave incident on Raman beams
Duan, Zhenglu; Hu, Liyun; Xu, XueXiang; Liu, Cunjin
2014-07-01
When a three-level atomic wavepacket is obliquely incident on a "edium slab" consisting of two far-detuned laser beams, there exists lateral shift between reflection and incident points at the surface of a "medium slab", analogous to optical Goos-Hanchen effect. We evaluate lateral shifts for reflected and transmitted waves via expansion of reflection and transmission coefficients, in contrast to the stationary phase method. Results show that lateral shifts can be either positive or negative dependent on the incident angle and the atomic internal state. Interestingly, a giant lateral shift of transmitted wave with high transmission probability is observed, which is helpful to observe such lateral shifts experimentally. Different from the two-level atomic wave case, we find that quantum interference between different atomic states plays crucial role on the transmission intensity and corresponding lateral shifts.
Absorption Spectra of a Three-Level Atom Embedded in a PBG Reservoir
Institute of Scientific and Technical Information of China (English)
ZHANG Ke; ZHANG Han-Zhuang
2007-01-01
We introduce the 'decay rate' terms into the density matrix equations of an atom embedded in a photonic band gap (PSG)reservoir successfully.By utilizing the master equations,the probe absorption spectra and the refractivity properties of a three-level atom in the PBG reservoir are obtained.The interaction between the atom and the PBG reservoir as well as the effects of the quantum interference on the absorption of the atom has also been taken into account.It is interesting that two different types of the anomalous dispersion relations of refractivity are exhibited in one dispersion line.The methodology used here can be applied to theoretical investigation of quantum interference effects of other atomic models embedded in a PBG reservoir.
Radiation pressure and laser cooling of a three-level atom in a ladder configuration
Institute of Scientific and Technical Information of China (English)
Tan Lei; Wang Zhi-Cheng; Gu Huai-Qiang
2004-01-01
Radiation pressure and laser cooling of a moving three-level ladder-type atom in bichromatic travelling fields are considered. The dependence of the force on parameters such as detunings, Rabi frequencies and spontaneous decay rates is calculated numerically and shown graphically, and analytical expressions for the force are obtained for some special parameter values. It is shown that the radiation pressure shows Doppler-shifted resonance peaks resulting respectively from one-photon and two-photon transitions. Using the present scheme, Doppler cooling of sodium exploiting the 3 2S1/2-3 2P3/2-3 2D5/2 cascade transitions is investigated. It is found that temperatures lower than the Doppler limit can be achieved.
Statistics of scattered photons from a driven three-level emitter in 1D open space
Energy Technology Data Exchange (ETDEWEB)
Roy, Dibyendu [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Div. and Center for Nonlinear Studies; Bondyopadhaya, Nilanjan [Visva-Bharati University, Santiniketan (India). Integrated Science Education and Research Centre
2014-01-07
We derive the statistics of scattered photons from a Λ- or ladder-type three-level emitter (3LE) embedded in a 1D open waveguide. The weak probe photons in the waveguide are coupled to one of the two allowed transitions of the 3LE, and the other transition is driven by a control beam. This system shows electromagnetically induced transparency (EIT) which is accompanied with the Autler-Townes splitting (ATS) at a strong driving by the control beam, and some of these effects have been observed recently. We show that the nature of second-order coherence of the transmitted probe photons near two-photon resonance changes from bunching to antibunching to constant as strength of the control beam is ramped up from zero to a higher value where the ATS appears.
Photon scattering by a three-level emitter in a one-dimensional waveguide
Witthaut, D
2010-01-01
We discuss the scattering of photons from a three-level emitter in a one-dimensional waveguide, where the transport is governed by the interference of spontaneously emitted and directly transmitted waves. The scattering problem is solved in closed form for different level structures. Several possible applications are discussed: The state of the emitter can be switched deterministically by Raman scattering, thus enabling applications in quantum computing such as a single photon transistor. An array of emitters gives rise to a photonic band gap structure, which can be tuned by a classical driving laser. A disordered array leads to Anderson localization of photons, where the localization length can again be controlled by an external driving.
Temperature limits in laser cooling of free atoms with three-level cascade transitions
Cruz, Flavio C; Magno, Wictor C
2013-01-01
We employ semiclassical theoretical analysis to study laser cooling of free atoms using three-level cascade transitions, where the upper transition is much weaker than the lower one. This represents an alternate cooling scheme, particularly useful for group II atoms. We find that temperatures below the Doppler limits associated with each of these transitions are expected. The lowest temperatures arise from a remarkable increase in damping and reduced diffusion compared to two-level cooling. They are reached at the two-photon resonance, where there is a crossing between the narrow and the partially-dark dressed states, and can be estimated simply by the usual Doppler limit considering the decay rate of the optical coherence between these states.
Spatial Four Wave Mixing, Probe Images, and Fluorescence Signals in Dressed Three-Level System
Lan, Huayan; Sun, Jia; Wu, Zhenkun; Zhang, Dan; Zhang, Yiqi; Zheng, Huaibin; Zhang, Yanpeng
2013-10-01
We investigate the spatial images of the probe, generated four wave mixing (FWM) signal and the accompanying fluorescence spectrum signal simultaneously in FWM process in a cascade three-level atomic system for the first time. We experimentally observe and theoretically investigate the three spectrum signals versus the probe field as well as the dressing field frequency detunings. Utilizing the experimental results of spectrum signals, the cross phase modulation and the relative position between the weak and strong beams, we analyze the characteristics indicated in the spatial images of probe transmission and FWM, such as focusing or defocusing, shift and splitting in detail. Such studies can be used in all-optical controlled spatial signal transmission.
Dynamics of cascade three-level system interacting with the classical and quantized ﬁeld
Indian Academy of Sciences (India)
Mihir Ranjan Nath; Surajit Sen; Gautam Gangopadhyay
2003-12-01
We study the exact solutions of the cascade three-level atom interacting with a single mode classical and quantized ﬁeld with different initial conditions ofthe atom. For the semiclassical model, it is found that if the atom is initially in the middle level, the time-dependent populations of the upper and lower levels are always equal. This dynamical symmetry exhibited by the classical ﬁeld is spoiled on quantization of the ﬁeld mode. To reveal this non-classical effect, a Euler matrix formalism is developed to solve the dressed states of the cascade Jaynes–Cummings model (JCM). Possible modiﬁcation of such an effect on the collapse and revival phenomenon is also discussed by taking the quantized ﬁeld in a coherent state.
A Novel Neutral Point Voltage Control Strategy for Three-Level NPC APF Based on SVPWM
Directory of Open Access Journals (Sweden)
Yao Xiaolong
2015-01-01
Full Text Available The unbalance of the neutral point voltage is an inherent problem of three-level neutral-point-clamped (NPC Active Power Filter (APF; this paper analyzes the causes of unbalanced neutral point voltage and studies the reason of the unbalance of the neutral point voltage. A novel neutral point voltage control strategy using Space Vector Pulse Width Modulation (SVPWM is proposed. The proposed strategy is based on the traditional SVPWM, by controlling the effect time of small vector, which can change the state of the midpoint voltage fluctuation, and the neutral point voltage can be maintained balance. The influence of the vector on neutral point balance is investigated in depth. Simulation results show the neutral point voltage balancing control strategy based on SPWM is effective.
Social Influence Study in Online Networks：A Three-Level Review
Institute of Scientific and Technical Information of China (English)
李辉; 崔江涛; 马建峰
2015-01-01
Social network analysis (SNA) views social relationships in terms of network theory consisting of nodes and ties. Nodes are the individual actors within the networks; ties are the relationships between the actors. In the sequel, we will use the term node and individual interchangeably. The relationship could be friendship, communication, trust, etc. These reason is that these relationships and ties are driven by social influence, which is the most important phenomenon that distinguishes social network from other networks. In this paper, we present an overview of the representative research work in social influence study. Those studies can be classified into three levels, namely individual, community, and network levels. Throughout the study, we are able to unveil a series of research directions in future and possible applications based on the state-of-the-art study.
Wang, Zhiping; Cao, Dewei; Yu, Benli
2016-05-01
We present a new scheme for three-dimensional (3D) atom localization in a three-level atomic system via measuring the absorption of a weak probe field. Owing to the space-dependent atom-field interaction, the position probability distribution of the atom can be directly determined by measuring the probe absorption. It is found that, by properly varying the parameters of the system, the probability of finding the atom in 3D space can be almost 100%. Our scheme opens a promising way to achieve high-precision and high-efficiency 3D atom localization, which provides some potential applications in laser cooling or atom nano-lithography via atom localization.
Jerger, Markus; Macha, Pascal; Hamann, Andrés Rosario; Reshitnyk, Yarema; Juliusson, Kristinn; Fedorov, Arkady
2016-07-01
Binary-outcome measurements allow one to determine whether a multilevel quantum system is in a certain state while preserving quantum coherence between all orthogonal states. In this paper, we explore different regimes of the dispersive readout of a three-level superconducting quantum system coupled to a microwave cavity in order to implement binary-outcome measurements. By designing identical cavity-frequency shifts for the first and second excited states of the system, we realize strong projective binary-outcome measurements onto its ground state with a fidelity of 94.3%. Complemented with standard microwave control and low-noise parametric amplification, this scheme enables the quantum nondemolition detection of leakage errors and can be used to create sets of compatible measurements to reveal the contextual nature of superconducting circuits.
Directory of Open Access Journals (Sweden)
Ahmad Jaafarnehad
2015-09-01
Full Text Available The role and importance of supply chain management, has faced with many challenges and problems. Although a comprehensive model of supply chain issues, has not been explained, we have to indicate that issues such as reviewing the theoretical foundations of information systems, marketing, financial management, logistical and organizational relations have been considered by many researchers. The objective of supply chain management is to improve various activities and components to increase overall supply chain system benefits. In order to achieve the overall objectives, many contradictions may occur between the components and different levels of supply chain and the contradictions that these disorders over time, result in decreased strength and competitiveness of the supply chain. Such conflicts, like marketing costs (advertising, pricing and inventory can occur during the supply chain life cycle. A Game Theory approach with respect to property is the appropriate tool for collaboration in the supply chain. This tool is used for collaborative making in any kind of supply chain such as cooperative supply chain and non-cooperative supply chain. In the present study and assuming a lack of cooperation between different levels of a supply chain, a dynamic game with complete information has been generated. In addition identifying appropriate leaders of various levels of the supply chain is considered. Non-Cooperative dynamic game mode (Stackelberg Game, for each of the three levels of supply chain including retailers, suppliers and manufacturers are modeled. Depending on the bargaining power and its position in the market, any level of supply chain can make a leader of the following rule. In the present study, the equilibrium model to play Stackelberg game may be led by a leader or leading players and ultimately identifying and modeling the appropriate unlimited three level supply chain are determined.
Analysis and identification of two reconstituted tobacco sheets by three-level infrared spectroscopy
Wu, Xian-xue; Xu, Chang-hua; Li, Ming; Sun, Su-qin; Li, Jin-ming; Dong, Wei
2014-07-01
Two kinds of reconstituted tobacco (RT) from France (RTF) and China (RTC) were analyzed and identified by a three-level infrared spectroscopy method (Fourier-transform infrared spectroscopy (FT-IR) coupled with second derivative infrared spectroscopy (SD-IR) and two-dimensional infrared correlation spectroscopy (2D-IR)). The conventional IR spectra of RTF parallel samples were more consistent than those of RTC according to their overlapped parallel spectra and IR spectra correlation coefficients. FT-IR spectra of both two RTs were similar in holistic spectral profile except for small differences around 1430 cm-1, indicating that they have similar chemical constituents. By analysis of SD-IR spectra of RTFs and RTCs, more distinct fingerprint features, especially peaks at 1106 (1110), 1054 (1059) and 877 (874) cm-1, were disclosed. Even better reproducibility of five SD-IR spectra of RTF in 1750-1400 cm-1 could be seen intuitively from their stacked spectra and could be confirmed by further similarity evaluation of SD-IR spectra. Existence of calcium carbonate and calcium oxalate could be easily observed in two RTs by comparing their spectra with references. Furthermore, the 2D-IR spectra provided obvious, vivid and intuitive differences of RTF and RTC. Both two RTs had a pair of strong positive auto-peaks in 1600-1400 cm-1. Specifically, the autopeak at 1586 cm-1 in RTF was stronger than the one around 1421 cm-1, whereas the one at 1587 cm-1 in RTC was weaker than that at 1458 cm-1. Consequently, the RTs of two different brands were analyzed and identified thoroughly and RTF had better homogeneity than RTC. As a result, three-level infrared spectroscopy method has proved to be a simple, convenient and efficient method for rapid discrimination and homogeneousness estimation of RT.
Passive synchronized Q-switching between a quasi-three-level and a four-level laser
DEFF Research Database (Denmark)
Cheng, Haynes Pak Hay; Tidemand-Lichtenberg, Peter; Jensen, Ole Bjarlin;
2011-01-01
Synchronized Q-switching between quasi-three-level and four-level lasers is interesting for sum-frequency generation into the blue and ultraviolet. We report, for the first time, stable synchronized Q-switching between a quasi-three-level laser at 946 nm and a four-level laser at 1064 nm in an al...
Zou, Xubo; Mathis, W.
2004-09-01
We propose an experimental scheme for one-step implementation of maximally entangled states of many three-level atoms in microwave cavity QED. In the scheme, many three-level atoms initially prepared in the same superposition states are simultaneously sent through one superconducting cavity, and maximally entangled states can be generated without requiring the measurement and individual addressing of the atoms.
Switching Characteristics of Ferroelectric Transistor Inverters
Laws, Crystal; Mitchell, Coey; MacLeod, Todd C.; Ho, Fat D.
2010-01-01
This paper presents the switching characteristics of an inverter circuit using a ferroelectric field effect transistor, FeFET. The propagation delay time characteristics, phl and plh are presented along with the output voltage rise and fall times, rise and fall. The propagation delay is the time-delay between the V50% transitions of the input and output voltages. The rise and fall times are the times required for the output voltages to transition between the voltage levels V10% and V90%. Comparisons are made between the MOSFET inverter and the ferroelectric transistor inverter.
Static Characteristics of the Ferroelectric Transistor Inverter
Mitchell, Cody; Laws, crystal; MacLeond, Todd C.; Ho, Fat D.
2010-01-01
The inverter is one of the most fundamental building blocks of digital logic, and it can be used as the foundation for understanding more complex logic gates and circuits. This paper presents the characteristics of an inverter circuit using a ferroelectric field-effect transistor. The voltage transfer characteristics are analyzed with respect to varying parameters such as supply voltage, input voltage, and load resistance. The effects of the ferroelectric layer between the gate and semiconductor are examined, and comparisons are made between the inverters using ferroelectric transistors and those using traditional MOSFETs.
Inverted CERN School of Computing
IT Department
2011-01-01
The 5th edition of the Inverted CERN School of Computing (iCSC, “Where students turn into teachers”) will take place next Thursday and Friday (3 and 4 of March) at CERN, Building 31 - IT Amphitheatre - Third Floor. Attendance is free and open to everyone. The programme is designed so that you can attend the lectures that interest you. This year highlights: Cloud Computing, Software Engineering, Cryptography Registration is not mandatory, but will allow you to obtain a copy of the full booklet (first registered, first served). Programme overview: Thursday 3 March 2011 10:00 - 10:15 Introduction School opening 10:15 - 11:10 Lecture 1 Virtualization: what it is, how it works – Luigi Gallerani 11:20 - 12:15 Lecture 2 Server Virtualization at work – Carlos Garcia Fernandez 14:00 - 14:55 Lecture 3 Unweaving Clouds: Principles and Practice – Belmiro Moreira 15:30 - 16:25 Lecture 4 Understanding Cryptography: From Caesar to Public-Key – Nicola...
Directory of Open Access Journals (Sweden)
Sandhya Seelam
2015-08-01
Full Text Available MATLABbasedsingle-phase three-level topology for a transformer less photovoltaic system is presented in this paper. Compared with the conventional H-bridge topology, it only needs two additional asymmetrically distributed switches, and the system common-mode voltage can be kept constant with a simple modulation scheme. Family of H6 transformer less inverter topologies with low leakage currents is proposed and highly efficient and reliable inverter concept (HERIC topology is also presented in this paper. The proposed inverter can also operate with high frequency by retaining high efficiency which enables reduced cooling system. Finally, the proposed new topology is simulated by MATLAB/Simulink software to validate the accuracy of the theoretical explanation.
Directory of Open Access Journals (Sweden)
Nor Faezah Alias
2013-12-01
Full Text Available Three-level Neutral Point Clamped (NPC inverter allows the configuration of switching devices to operate at high voltage and produce lower current/voltage harmonics. It is known that, DTC of induction machine which employs hysteresis controller has major drawbacks namely larger torque ripple and variable switching frequency. This paper aims to propose a suitable voltage vector selection to provide better torque regulation and lower switching frequency by employing DTC with 3-level NPC multilevel inverter. A simple switching strategy was formulated using 7-level torque hysteresis and 2-level flux hysteresis controllers to give more options in selecting an appropriate voltage vector, inherently, according the motor operation conditions. The improvements offered were verified through simulations.
Harmonics Study and Comparison of Z-source Inverter with Traditional Inverters
Directory of Open Access Journals (Sweden)
B. Justus Rabi
2005-01-01
Full Text Available This paper presents an Impedance Source Inverter for A.C electrical drives. The impedance source inverter employs a unique impedance network cable with inverter main circuit and rectifier. By controlling the shoot-through duty cycle, the z-source inverter system using MOSFETS provide ride-through capability during voltage sags, reduces line harmonics, improves power factor and high reliability, and extends output voltage range. Analysis, simulation, and experimental results will be presented to demonstrate these new features. It reduces harmonics, electromagnetic interference noise and it has low common mode noise.
Kobesova, Alena; Kolar, Pavel
2014-01-01
Three levels of sensorimotor control within the central nervous system (CNS) can be distinguished. During the neonatal stage, general movements and primitive reflexes are controlled at the spinal and brain stem levels. Analysis of the newborn's spontaneous general movements and the assessment of primitive reflexes is crucial in the screening and early recognition of a risk for abnormal development. Following the newborn period, the subcortical level of the CNS motor control emerges and matures mainly during the first year of life. This allows for basic trunk stabilization, a prerequisite for any phasic movement and for the locomotor function of the extremities. At the subcortical level, orofacial muscles and afferent information are automatically integrated within postural-locomotor patterns. Finally, the cortical (the highest) level of motor control increasingly becomes activated. Cortical control is important for the individual qualities and characteristics of movement. It also allows for isolated segmental movement and relaxation. A child with impaired cortical motor control may be diagnosed with developmental dyspraxia or developmental coordination disorder. Human ontogenetic models, i.e., developmental motor patterns, can be used in both the diagnosis and treatment of locomotor system dysfunction.
Spontaneous emission spectrum of a three-level atom embedded in photonic crystal
Institute of Scientific and Technical Information of China (English)
刘国强; 王健; 张汉壮
2005-01-01
The two models of three-level (one upper level and two lower levels, or two upper levels and one lower level) atom embedded in a double-band photonic crystal are adopted. The atomic transitions from the upper levels to the lower levels are assumed to be coupled by the same reservoir which are respectively the isotropic photonic band gap (PBG)modes, the anisotropic PBG modes and the free vacuum modes. The effects of the fine structure of the atomic ground state levels in the model with one upper level and two lower levels, and the quantum interferences in the model with two upper levels and one lower level on the spontaneous emission spectrum of an atom are investigated in detail. Most interestingly, it is shown that new spontaneous emission lines are produced from the fine splitting of atomic ground state levels in the isotropic PBG case. The quantum interferences induce additional narrow spontaneous lines near the transition from the empty upper level to the lower level.
Two-mode mazer injected with V-type three-level atoms
Institute of Scientific and Technical Information of China (English)
梁文青; 张智明; 谢绳武
2003-01-01
The properties of the two-mode mazer operating on V-type three-level atoms are studied. The effect of the oneatom pumping on the two modes of the cavity field in number-state is asymmetric, that is, the atom emits a photon into one mode with some probability and absorbs a photon from the other mode with some other probability. This effect makes the steady-state photon distribution and the steady-state photon statistics asymmetric for the two modes. The diagram of the probability currents for the photon distribution, given by the analysis of the master equation, reveals that there is no detailed balance solution for the master equation. The computations show that the photon statistics of one mode or both modes can be sub-Poissonian, that the two modes can have anticorrelation or correlation, that the photon statistics increases with the increase of thermal photons, and that the resonant position and strength of the photon statistics are influenced by the ratio of the two coupling strengths of the two modes. These properties are also discussed physically.
Coupling of a nano mechanical oscillator and an atomic three-level medium
Sanz-Mora, A; Wüster, S; Rost, J -M
2015-01-01
We theoretically investigate the coupling of an ultracold three-level atomic gas and a nano-mechanical mirror via classical electromagnetic radiation. The radiation pressure on the mirror is modulated by absorption of a probe light field, caused by the atoms which are electromagnetically rendered nearly transparent, allowing the gas to affect the mirror. In turn, the mirror can affect the gas as its vibrations generate opto-mechanical sidebands in the control field. We show that the sidebands cause modulations of the probe intensity at the mirror frequency, which can be enhanced near atomic resonances. Through the radiation pressure from the probe beam onto the mirror, this results in resonant driving of the mirror. Controllable by the two photon detuning, the phase relation of the driving to the mirror motion decides upon amplification or damping of mirror vibrations. This permits direct phase locking of laser amplitude modulations to the motion of a nano-mechanical element opening a perspective for cavity-f...
Analysis of three level supply chain of inventory with deterioration for multi-items
Directory of Open Access Journals (Sweden)
Narayan Singh
2014-05-01
Full Text Available The objective of this work is to generalize the three echelon supply chain model proposed by Jaber and Goyal (2008 [Jaber, M. Y., & Goyal, S. K. (2008. Coordinating a three-level supply chain with multiple suppliers, a vendor and multiple buyers. International Journal Production Economics, 116, 95-103.] for multi-items where single item was considered in production and distribution. This paper develops the coordination amongst different parties in a three-echelon supply chain with a centralized decision process. Producer, suppliers and retailers are the parties of the supply chain where multiple suppliers deliver various types of raw materials to a producer; producer produces different types of items, multi-items, in different units of the factory and supplies the items to multiple retailers. Different deterioration rates for finished items and raw materials are also considered. The model developed of this paper guarantees that the local costs for the members either remain the same as before coordination, or decrease as a result of coordination. A numerical example along with graphical illustrations is considered and the sensitivity analysis is provided to test the feasibility of the proposed model.
Variable universe adaptive fuzzy control on the quadruple inverted pendulum
Institute of Scientific and Technical Information of China (English)
李洪兴; 苗志宏; 王家银
2002-01-01
This paper focuses on the control problem of the quadruple inverted pendulum by variable universe adaptive fuzzy control.First,the mathematical model on the quadruple inverted pendulum is described and its controllability is versified.Then,an efficient controller on the quadruple inverted pendulum is designed by using variable universe adaptive fuzzy control theory.Finally the simulation of the quadruple inverted pendulum is shown in detail.Besides,the experimental results on the hardware systems,i.e.real object systems,on a single inverted pendulum,a double inverted pendulum and a triple inverted pendulum are briefly introduced.``
Directory of Open Access Journals (Sweden)
Ivan Enrici
Full Text Available Parkinson's disease (PD is characterised by well-known motor symptoms, whereas the presence of cognitive non-motor symptoms, such as emotional disturbances, is still underestimated. One of the major problems in studying emotion deficits in PD is an atomising approach that does not take into account different levels of emotion elaboration. Our study addressed the question of whether people with PD exhibit difficulties in one or more specific dimensions of emotion processing, investigating three different levels of analyses, that is, recognition, representation, and regulation.Thirty-two consecutive medicated patients with PD and 25 healthy controls were enrolled in the study. Participants performed a three-level analysis assessment of emotional processing using quantitative standardised emotional tasks: the Ekman 60-Faces for emotion recognition, the full 36-item version of the Reading the Mind in the Eyes (RME for emotion representation, and the 20-item Toronto Alexithymia Scale (TAS-20 for emotion regulation.Regarding emotion recognition, patients obtained significantly worse scores than controls in the total score of Ekman 60-Faces but not in any other basic emotions. For emotion representation, patients obtained significantly worse scores than controls in the RME experimental score but no in the RME gender control task. Finally, on emotion regulation, PD and controls did not perform differently at TAS-20 and no specific differences were found on TAS-20 subscales. The PD impairments on emotion recognition and representation do not correlate with dopamine therapy, disease severity, or with the duration of illness. These results are independent from other cognitive processes, such as global cognitive status and executive function, or from psychiatric status, such as depression, anxiety or apathy.These results may contribute to better understanding of the emotional problems that are often seen in patients with PD and the measures used to test
Average Dissipative and Dipole Forces on a Three-Level Atom in a Laguerre-Gaussian Beam
Institute of Scientific and Technical Information of China (English)
WANG Zheng-Ling; YIN Jian-Ping
2005-01-01
@@ By means of the optical Bloch equations based on the atomic density matrix elements, the general expressions of the average dissipative force, dipole force and the mechanical torque acting on a A-configuration three-level atom in a linearly-polarized Laguerre-Gaussian beam (LGB) with an angular momentum of lh are derived, and the general properties of the average dissipative and dipole force on the three-level atom in the linearly-polarized LGB are analysed. We find a resonant property (with two resonant peaks) of the dissipative force and a non-resonant property (with two pairs of non-resonant peaks) of the dipole force on the three-level atom, which are completely different from those on the two-level atom. Our study also shows that all of general expressions on the three-level atom will be simplified to those on the two-level atom in the approximation of large detuning.
Institute of Scientific and Technical Information of China (English)
2011-01-01
A single phase three-level converter （shown in Fig. 1） has been widely applied in high-speed railway electrical traction drive systems. But the main technical drawback of the three-level converter is DC-link neutral point voltage drift. In order to solve this problem, it is important to understand the cause of DC-link neutral point voltage drift.
Performance analysis of new type grid-tied inverter-Aalborg Inverter
DEFF Research Database (Denmark)
Wu, Weimin; Wang, Zhen; Ji, Junhao;
2014-01-01
Aalborg Inverter is a grid-tied DC/AC inverter. In order to optimize the design, its power losses are analyzed in detail, combined with a description of the single-phase operating principle and the modulation strategy. A 2 kW / 220 V experimental prototype is constructed to verify the theoretical...
Directory of Open Access Journals (Sweden)
Kil To Chong
2013-10-01
Full Text Available The main objective of the present work is to apply a sliding mode controller (SMC to medium voltage and high power output energy recovery Li-ion power accumulator battery pack testing systems (ERLPABTSs, which are composed of a three-level neutral-point-clamped (NPC three-phase voltage source inverter (VSI and a two-level buck-boost converter without an isolating transformer. An inner current decoupled control scheme for the aforementioned system is proposed and two sliding mode planes for active and reactive current control are designed based on the control scheme. An optimized switching table for current convergence is used according to the error sign of the equivalent input voltage and feedback voltage. The proposed ERLPABTS could be used to integrate discharging energy into the power grid when performing high accuracy current testing. The active and reactive power references for the grid-connected inverter are determined based on the discharging energy from the DC-DC converter. Simulations and experiments on a laboratory hardware platform using a 175 kW insulated gate bipolar transistor (IGBT-based ERLPABTS have been implemented and verified, and the performance is found satisfactory and superior to conventional ERLPABPTS.
An SCR inverter for electric vehicles
Latos, T.; Bosack, D.; Ehrlich, R.; Jahns, T.; Mezera, J.; Thimmesch, D.
1980-01-01
An inverter for an electric vehicle propulsion application has been designed and constructed to excite a polyphase induction motor from a fixed propulsion battery source. The inverter, rated at 35kW peak power, is fully regenerative and permits vehicle operation in both the forward and reverse directions. Thyristors are employed as the power switching devices arranged in a dc bus commutated topology. This paper describes the major role the controller plays in generating the motor excitation voltage and frequency to deliver performance similar to dc systems. Motoring efficiency test data for the controller are presented. It is concluded that an SCR inverter in conjunction with an ac induction motor is a viable alternative to present dc vehicle propulsion systems on the basis of performance and size criteria.
Power inverter implementing phase skipping control
Somani, Utsav; Amirahmadi, Ahmadreza; Jourdan, Charles; Batarseh, Issa
2016-10-18
A power inverter includes a DC/AC inverter having first, second and third phase circuitry coupled to receive power from a power source. A controller is coupled to a driver for each of the first, second and third phase circuitry (control input drivers). The controller includes an associated memory storing a phase skipping control algorithm, wherein the controller is coupled to receive updating information including a power level generated by the power source. The drivers are coupled to control inputs of the first, second and third phase circuitry, where the drivers are configured for receiving phase skipping control signals from the controller and outputting mode selection signals configured to dynamically select an operating mode for the DC/AC inverter from a Normal Control operation and a Phase Skipping Control operation which have different power injection patterns through the first, second and third phase circuitry depending upon the power level.
Maskless inverted pyramid texturization of silicon.
Wang, Yan; Yang, Lixia; Liu, Yaoping; Mei, Zengxia; Chen, Wei; Li, Junqiang; Liang, Huili; Kuznetsov, Andrej; Xiaolong, Du
2015-06-02
We discovered a technical solution of such outstanding importance that it can trigger new approaches in silicon wet etching processing and, in particular, photovoltaic cell manufacturing. The so called inverted pyramid arrays, outperforming conventional pyramid textures and black silicon because of their superior light-trapping and structure characteristics, can currently only be achieved using more complex techniques involving lithography, laser processing, etc. Importantly, our data demonstrate a feasibility of inverted pyramidal texturization of silicon by maskless Cu-nanoparticles assisted etching in Cu(NO3)2 / HF / H2O2 / H2O solutions and as such may have significant impacts on communities of fellow researchers and industrialists.
Cascaded impedance networks for NPC inverter
DEFF Research Database (Denmark)
Li, Ding; Gao, Feng; Loh, Poh Chiang;
2010-01-01
would have a higher output voltage gain. It is anticipated that it would help the formed inverters find applications in photovoltaic and other renewable systems, where a high voltage gain is usually requested. Experimental testing has already been conducted and verifies the theory. ©2010 IEEE....... they are subject to the renewable sources. To date, three distinct types of impedance networks can be summarized for implementing a hybrid source impedance network, which can in principle be combined and cascaded before connected to a NPC inverter by proposed two ways. The resulting cascaded impedance network NPC...
Decoupling Control Strategy for Single Phase SPWM Parallel Inverters
Institute of Scientific and Technical Information of China (English)
Shun-Gang Xu; Jian-Ping Xu; Tai-Qiang Cao
2009-01-01
A decoupling control strategy of inverter parallel system is proposed based on the equivalent output impedance of single phase voltage source SPWM (sinusoidal pulse width modulation) inverter. The active power and reactive power are calculated in terms of output voltage and current of the inverter, and sent to the other inverters in the parallel system via controller area network (CAN) bus. By calculating and decoupling the circumfluence of the active power and reactive power, the inverters can share load current via the regulation of the reference-signal phase and amplitude. Experimental results of an 110V/2kVA inverter parallel system show the feasibility of the decoupling control strategy.
Biess, J. J.; Inouye, L. Y.; Shank, J. H.
1974-01-01
A high-voltage, high-power LC series resonant inverter using SCRs has been developed for an Ion Engine Power Processor. The inverter operates within 200-400Vdc with a maximum output power of 2.5kW. The inverter control logic, the screen supply electrical and mechanical characteristics, the efficiency and losses in power components, regulation on the dual feedback principle, the SCR waveforms and the component weight are analyzed. Efficiency of 90.5% and weight density of 4.1kg/kW are obtained.
The Controller Based on the Buck/Boost solar LED street lamp%基于Buck/Boost太阳能LED路灯控制器
Institute of Scientific and Technical Information of China (English)
曲帅帅; 王志坤
2014-01-01
本系统以STC12C5410AD单片机为核心，以两只VMOS管为基本控制单元，在电路极为简单自身功耗很小的情况下实现了对太阳能路灯系统的智能化管理；系统采用了一种自适应性算法的MPP最大功率追踪控制法，实现了在同样光照条件下太阳能电池发电量最大化的控制，设计了电池板智能追光与自动清洁板面的机械结构，使各个时间段的光线与电池板都能保持最佳角度，同时做到了强光时降压防过充、弱光时升压继续充的全功能充电控制。%this system with STC12C5410AD MCU as the core,with two VMOS tube as a basic control unit,in the circuit is extremely simple to very smal self power consumption under the condition of realization of solar streetlight system intel igent management;system using an adaptive algorithm of the MPP maximum power tracking control method,realized in the same light under the condition of maximum power output of the solar battery control,design of intel igent light battery plate with automatic cleaning surface mechanical structure,so that each time the light and battery plate can keep the best angle,at the same time to light pressure overcharge protection,weak light booster continue to charge the ful functionality of the charging control.
Understanding USB-C Buck-Boost battery charging%解密USB-C升压-降压电池充电
Institute of Scientific and Technical Information of China (English)
魏佳
2016-01-01
本文分析了传统PC电源架构，描述了随着可反转USB Type-CTM线缆连接器的USB-C输电的广泛应用，PC电源架构将发生较大的变化。通过探讨不同的电池充电方法，解释了USB-C升压-降压充电拓扑如何才能提供设计工程师要求的灵活性、高效率和小解决方案尺寸。
Digital DC-DC Converter Based on Buck-Boost Topology%基于Buck Boost拓扑的数字DC DC变换器设计
Institute of Scientific and Technical Information of China (English)
杜英; 郝茂森
2014-01-01
针对常规DC DC变换器输出电压调整困难、反馈实现复杂、智能化程度低的问题，提出了一种新型的能够根据用户要求快速改变输出电压的DC DC变换器，并且能够根据电源输入的电压变化情况实时调整控制参数，实现稳定的电压输出，且输出电压不受输入电压变化的影响。通过对不同负载和电源输入变化的实验验证，该DC DC变换器具有输出电压稳定精确、纹波率小、反馈快速准确的特点，对于某些对输入电压稳定性要求高的场合有实际应用意义。%Against the fact that the voltage values of DC-DC converter is difficult to adjust due to complex feedback and low degree of in-telligence,this paper proposes a new type of DC-DC converter that can be adjusted easily.This converter can adjust the control parame-ters along with the input voltage,keeping the output voltage stable.Experiments of different loads and input voltage show that this DC-DC converter has the advantage of stable output voltage,low voltage fluctuation,quick and accurate feedback.It has practical meaning in terms of requiring stable output voltage.
Simulated Analysis of APFC for BUCK- BOOST Converter with Matlab%用Matlab实现BUCK-BOOST变换器 APFC的仿真分析
Institute of Scientific and Technical Information of China (English)
刘宇; 谢品芳; 周雒维
2001-01-01
本文分析了用BUCK-BOOST电路进行功率因素校正的原理和变换过程,给出了BUCK-BOOS电路的Matlab仿真分析的模型.通过对变换器工作在DCM模式下的电路仿真,验证了此方法具有良好的效果.
新颖的Buck-Boost高频环节AC/AC变换器%Novel Buck-Boost AC/AC Converters with High Frequency Link
Institute of Scientific and Technical Information of China (English)
刘剑; 陈道炼; 尹春
2004-01-01
提出了Buck-Boost高频环节AC/AC变换器电路拓扑,该电路拓扑由输入周波变换器、高频储能式变压器、输出周波变换器构成.分析研究了该变换器工作模式和电压瞬时值反馈控制策略.理论分析和试验表明,该变换器具有两级功率变换(LFAC/HFAC/LFAC)、双向功率流、网侧电流波形可得到改善、负载适应能力强、音频噪音小等优点.
A Novel Four Switch Buck-Boost Converter%一种新颖的四开关Buck-Boost变换器
Institute of Scientific and Technical Information of China (English)
任小永; 唐钊; 阮新波; 危建; 华桂潮
2008-01-01
提出一种新颖的四开关Buck-Boost变换器及其控制策略.该变换器由Buck变换器和Boost变换器级联等效而成,其可以将宽范围的输入电压高效率变换到额定电压附近,这样对后级变换器而言输入就是一个窄范围,从而保证了后级变换器的优化设计;与此同时,四开关Buck-Boost变换器的滤波工作模式还保证了额定输入电压附近效率的最高.实验结果表明:采用文中提出的四开关Buck-Boost变换器作为前级的两级式变换器可以满足未来通信电源模块高效率、高功率密度以及宽输入范围的要求.
几种新型的Buck-Boost变换器的合成%Synthesis of Several Novel Buck-Boost Converters
Institute of Scientific and Technical Information of China (English)
朱继承; 蔡丽娟
2008-01-01
从传输机制说明单管升降压变换器(如Buck-Boost、SPEIC、Cuk)中元件承受的电压和电流应力高的原因,并根据这一机制,采用变换器合成的方式,提出了一系列的双管Buck-Boost变换器.这类变换器根据输入输出条件,可以分别工作于Boost模式和Buck模式,起到降低元件应力的作用.
Design of isolated Buck-Boost DC/DC converter%Buck-Boost隔离直流转换器设计
Institute of Scientific and Technical Information of China (English)
王雪丹; 李文鹤
2013-01-01
在Buck-Boost隔离直流转换器宽范围输入电压的条件下,分析了典型的全桥boost转换器拓扑结构,由于存在的谐振电感包括漏电感,全桥Boost转换器只能采用双边沿调制[1],该转换器采用UC3895作为控制器,对全桥单元采用移相转换控制的方式,为了提高全桥boost转换器系统的可靠性和效率,采用三模式两频率控制方式[2],在输入宽范围电压的情况下,最高输入500V,输出360V,采用Matlab软件进行仿真,实验结果表明输入电压平均效率范围是96.2％,最高效率能达到97.5％.
高动态响应的Buck-Boost变换器的边界控制%Boundary Control of Buck-Boost Converter with Fast Response
Institute of Scientific and Technical Information of China (English)
马朋; 陆益民
2007-01-01
应用状态轨迹预测的方法,调节Buck-Boost变换器电压输出.根据在一个假定的开关动作后预测电压输出,设计二阶开关面,在一个开关周期内就可引导系统轨迹到达目标工作点,具有大信号稳定性,对负载扰动及电源扰动均有很强的自适应性,通过仿真验证了理论的正确性.
Buck-Boost变换器的环路补偿及仿真%Loop Compensation and Simulation of Buck-Boost Converter
Institute of Scientific and Technical Information of China (English)
于月森; 戚文艳
2014-01-01
设计DC-DC变换器时为了使其满足静态和动态指标的要求,一般需要设计良好的补偿网络,而变换器输出滤波电容的等效串联电阻ESR对补偿网络的影响是不可忽略的.为了探究等效串联电阻对补偿网络的影响,该文采用波特图法对工作在连续工作模式(CCM模式)下的Buck-Boost变换器的稳定性进行分析,并讨论了有无ESR时补偿器的设计方案,结果显示ESR不同,选用的补偿方案也不同;然后利用Matlab工具对补偿后的Buck-Boost变换器进行仿真,验证补偿网络设计的正确性.
Research on Buck-Boost Double Half Bridge DC/DC Converter%Buck-Boost型双半桥DC/DC变换器研究
Institute of Scientific and Technical Information of China (English)
施林涵; 林国庆; 徐质彬; 林威伟
2016-01-01
本文设计了一个应用于光伏系统中的Buck-Boost型双半桥DC/DC变换器,研究一种PWM控制与移相控制结合的充电与供电控制策略:通过移相控制实现光伏电池对负载的供电,通过PWM控制实现光伏电池对蓄电池的充电.最后结合仿真和实验结果,验证了该方案的可行性.
The Design and Implement of Digital Controller for Buck-Boost Converter%Buck-Boost变换器数字控制器的设计和实现
Institute of Scientific and Technical Information of China (English)
何炯; 吴定会; 纪志成
2008-01-01
利用分段线性电子电路仿真PLECS软件建立Buck-Boost变换器的仿真模型;采用幅值相位裕度方法设计控制器参数;基丁系统发生器提出了一种新的数字控制器实现方法,分析了负载扰动和电源扰动特性.并对其进行了实验.实验结果证明了PLECS建模和系统发生器设计的有效性,也为FPGA实现Buck-Boost变换器的数字控制器提供了新的设计流程.
PT controlled PCCM Buck-Boost converter with two control variables%两控制变量PT控制PCCM Buck-Boost变换器
Institute of Scientific and Technical Information of China (English)
秦明; 李芳芳
2016-01-01
为减小电感惯性模态期间电感电流下降对下一周期脉冲的影响,根据伪连续导电模式(Pseudo ContinuousConduction Mode,PCCM) Buck-Boost变换器的工作特点,提出一种新的脉冲序列(Pulse Train,PT)控制策略.控制策略中包含两个控制变量,使控制器根据不同能量的电压控制脉冲产生不同的电流控制脉冲.详细分析了新型PT控制策略下PCCM Buck-Boost变换器的工作过程,给出了高低能量电压控制脉冲比.仿真与实验结果验证了新型控制策略的可行性及理论分析的正确性.
Buck-Boost型变换器电路结构及其演化%Circuit Configuration and Derivation of the Buck-Boost Converter
Institute of Scientific and Technical Information of China (English)
张灵改; 陈道炼
2009-01-01
论述了基于Buck-Boost型变换器的DC/DC,DC/AC和AC/AC变换器电路结构及其演化过程,给出了各类变换器的电路拓扑实例、仿真和原理试验结果.理论分析、仿真和原理试验结果表明,Buck-Boost型变换器在中小容量的DC/DC.DC/AC和AC/AC电能变换中具有重要的应用价值.
基于MATLAB的Buck/Boost直流变换器仿真%The Simulation of Buck/Boost DC-DC Converter Based on MATLAB
Institute of Scientific and Technical Information of China (English)
韩学民
2006-01-01
对Buck和Boost直流变换器电路进行介绍,并且应用Matlab分别进行建模、仿真.在仿真过程中,改变触发脉冲的占空比,从而改变变换器的输出电压、电流,与理论分析结果进行比较.
Design of AC Regulator Based on Buck-Boost Converter%基于Buck-Boost的AC/AC变换器设计
Institute of Scientific and Technical Information of China (English)
张超华; 汤雨; 谢少军
2007-01-01
利用Buck-Boost电路输出电压理论上可以在零到无穷大之间变化的特点,将Buck- Boost斩波电路应用于交流电压变换,提出了一种变比可以连续变化的固态变压器.与传统的自耦调压器相比,基于Buck-Boost变换器的固态变压器具有输出电压范围宽、体积小的特点,并且由于采用了电压反馈控制,使得其输出电压不受负载变化的影响,外特性较硬.针对四象限开关存在的换流问题,提出了该变换器的换流策略,在理论分析的基础上,设计制作了一台AC/AC调压器,实验结果验证了该变换器的可行性.
The Passivity-based Current Control Method for BUCK-BOOST Converter%BUCK-BOOST变换器的无源性电流控制方法
Institute of Scientific and Technical Information of China (English)
廖鸿飞; 帅定新; 梁奇峰; 彭建宇
2013-01-01
为了简化系统控制结构,提高Buck-Boost变换器的控制性能,提出了一种通过直接控制电感电流间接控制输出电压的Buck-Boost变换器无源性电流控制方法.首先根据无源性控制方法建立了系统的欧拉一拉格朗日能量模型,然后基于无源性理论和Layapunov稳定性理论,推导出了系统的无源性控制规律.实验结果表明,系统输出电压稳定,鲁棒性较强,动态响应良好.
Dual Edge Modulated Four-switch Buck-Boost Converter%双沿调制的四开关Buck-Boost变换器
Institute of Scientific and Technical Information of China (English)
任小永; 阮新波; 李明秋; 钱海; 陈乾宏
2009-01-01
与传统的Buck-Boost变换器相比,四开关Buck-Boost变换器具有输入输出同极性、开关管电压应力低等优点.该文针对四开关Buck-Boost变换器在通信电源分布式系统中的应用,提出三模式双频双沿调制的控制策略.该控制策略将变换器分成Buck单元和Boost单元,此两单元分别采用后沿调制和前沿调制,并且在Buck.Boost工作模式时,开关频率由Buck以及Boost模式的200 kHz降到40 kHz,以提高变换器的效率.实验室制作了一台48V(33～75 V)输入48 V/6.25 A的样机,对所提出的控制策略进行验证.试验结果表明所得结论正确.
Fractional Order Modeling and Analysis of Buck-Boost Converter%基于分数阶Buck-Boost变换器建模与分析
Institute of Scientific and Technical Information of China (English)
伊利峰; 张开如; 刘军
2015-01-01
对Buck-Boost变换器应用相关分数阶微积分理论建立基于电感电流连续模式下分数阶数学模型,然后理论分析建立起来的分数阶数学模型.基于改进的分数阶微积分Oustaloup滤波器算法,建立电感电流连续模式下Buck-Boost变换器Matlab/Simulink分数阶仿真模型.最后,分数阶仿真结果与整数阶的结果进行分析比较,验证分数阶数学模型与理论分析的正确性.
Almeida, Pedro Santos
2012-01-01
Este trabalho apresenta um estudo acerca da alimentação de diodos emissores de luz (LEDs) a partir da rede elétrica empregando conversores eletrônicos com correção do fator de potência. O estudo visa o desenvolvimento de um conversor que pode ser aplicado em iluminação pública, que atenda às demandas típicas de alto fator de potência, alta eficiência, reduzido número de componentes, baixa distorção harmônica da corrente de entrada e possa atingir uma elevada vida útil, através ...
Teleporting N-qubit unknown atomic state by utilizing the Ⅴ-type three-level atom
Institute of Scientific and Technical Information of China (English)
ZHANG XinHua; YANG ZhiYong; XU PeiPei
2009-01-01
Realizing the teleportation of quantum state, especially the teleportation of N-qubit quantum state, is of great importance in quantum information. In this paper, Raman-interaction of the Ⅴ-type degenerate three-level atom and single-mode cavity field is studied by utilizing complete quantum theory. Then a new scheme for teleporting N-qubit unknown atomic state via Raman-interaction of the Ⅴ-type degen-erate three-level atom with a single-mode cavity field is proposed, which is based upon the complete quantum theory mentioned above.
Mohamed, A.-B. A.; Eleuch, H.
2017-02-01
An analytical description of a three-level atom in an optical cavity coupled to the environment is obtained. The Husimi function and the Wehrl density are calculated to investigate the information loss dynamics of the phase space. The Wehrl entropy and the atomic information entropy are explored to study the coherence loss of the three-level system. We show that these measures, as non-classical indicators, are very sensitive not only to the coupling strength to the reservoir but also to the initial state.
Teleporting N-qubit unknown atomic state by utilizing the V-type three-level atom
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
Realizing the teleportation of quantum state, especially the teleportation of N-qubit quantum state, is of great importance in quantum information. In this paper, Raman-interaction of the V-type degenerate three-level atom and single-mode cavity field is studied by utilizing complete quantum theory. Then a new scheme for teleporting N-qubit unknown atomic state via Raman-interaction of the V-type degenerate three-level atom with a single-mode cavity field is proposed, which is based upon the complete quantum theory mentioned above.
Strong Connections and Invertible Weak Entwining Structures
Institute of Scientific and Technical Information of China (English)
J.N.ALONSO (A)LVAREZ; J.M.FERN(A)NDEZ VILABOA; R.GONZ(A)LEZ RODR(I)GUEZ
2012-01-01
In this paper we obtain a criterion under which the bijectivity of the canonical morphism of a weak Galois extension associated to a weak invertible entwining structure is equivalent to the existence of a strong connection form.Also we obtain an explicit formula for a strong connection under equivariant projective conditions or under coseparability conditions.
The inverted pendulum : A singularity theory approach
Broer, H.W.; Hoveijn, I.; Noort, M. van; Vegter, G.
1999-01-01
The inverted pendulum with small parametric forcing is considered as an example of a wider class of parametrically forced Hamiltonian systems. The qualitative dynamics of the Poincaré map corresponding to the central periodic solution is studied via an approximating integrable normal form. At bifurc
[Inverted papiloma and its rare forms].
Bugová, G; Jeseňák, M; Wallenfels, P; Ondrušová, B; Hajtman, A
2014-01-01
Authors address the issue of a frequent benign tumour of the nasal cavity and paranasal sinuses - inverted papilloma. They analyse the available diagnostic methods and treatment options. On the background of selected case reports of a rare malignant transformation they emphasize the need for longterm dispensarization as a part of management plan for patients with this oncological disease.
Smart Inverters for Utility and Industry Applications
DEFF Research Database (Denmark)
Xue, Yaosuo; Guerrero, Josep M.
2015-01-01
Smart inverters are emerging with increasing renewable energy and smart grid development. While the recent work reviewed mostly focuses on defining standardized control functionalities and smart grid communication protocols, we take a holistic approach in this paper and propose a holon-type smart...
Solar Power Station Output Inverter Control Design
Directory of Open Access Journals (Sweden)
J. Bauer
2011-04-01
Full Text Available The photovoltaic applications spreads in these days fast, therefore they also undergo great development. Because the amount of the energy obtained from the panel depends on the surrounding conditions, as intensity of the sun exposure or the temperature of the solar array, the converter must be connected to the panel output. The Solar system equipped with inverter can supply small loads like notebooks, mobile chargers etc. in the places where the supplying network is not present. Or the system can be used as a generator and it shall deliver energy to the supply network. Each type of the application has different requirements on the converter and its control algorithm. But for all of them the one thing is common – the maximal efficiency. The paper focuses on design and simulation of the low power inverter that acts as output part of the whole converter. In the paper the design of the control algorithm of the inverter for both types of inverter application – for islanding mode and for operation on the supply grid – is discussed. Attention is also paid to the design of the output filter that should reduce negative side effects of the converter on the supply network.
Inverted porphyrins and expanded porphyrins: An overview
Indian Academy of Sciences (India)
S K Pushpan; S Venkatraman; V G Anand; J Sankar; H Rath; T K Chandrashekar
2002-08-01
Porphyrins and metallopophyrins have attracted the attention of chemists for the past 100 years or more owing to their widespread involvement in biology. More recently, synthetic porphyrins and porphyrin-like macrocycles have attracted the attention of researchers due to their diverse applications as sensitizers for photodynamic therapy, MRI contrasting agents, and complexing agents for larger metal ions and also for their anion binding abilities. The number of -electrons in the porphyrin ring can be increased either by increasing the number of conjugated double bonds between the pyrrole rings or by increasing the number of heterocyclic rings. Thus, 22 sapphyrins, 26 rubyrins, 30 heptaphyrins, 34 octaphyrins and higher cyclic polypyrrole analogues containing 40, 48, 64, 80 and 96 systems have recently been reported in the literature. These macrocycles show rich structural diversity where normal and different kinds of inverted structures have been identified. In this review, an attempt has been made to collect the literature of the inverted porphyrins and expanded porphyrins reported until December 2001. Since the meso aryl expanded porphyrins have tendency to form both inverted and non-inverted structures more emphasis has been given to meso aryl expanded porphyrins.
Operating temperatures of open-rack installed photovoltaic inverters
Energy Technology Data Exchange (ETDEWEB)
Zhang, Z.; Wang, L.; Kurtz, S.; Wu, J.; Quan, P.; Sorensen, R.; Liu, S.; Bai, J. B.; Zhu, Z. W.
2016-11-01
This paper presents a model for evaluating the heat-sink and component temperatures of open-rack installed photovoltaic inverters. These temperatures can be used for predicting inverter reliability. Inverter heat-sink temperatures were measured for inverters connected to three grid-connected PV (photovoltaic) test systems in Golden, Colorado, US. A model is proposed for calculating the inverter heat-sink temperature based on the ambient temperature, the ratio of the consumed power to the rated power of the inverter, and the measured wind speed. To verify and study this model, more than one year of inverter DC/AC power, irradiance, wind speed, and heat sink temperature rise data were collected and analyzed. The model is shown to be accurate in predicting average inverter temperatures, but will require further refinement for prediction of transient temperatures.
Study on inverter fault-tolerant operation of PMSM DTC
Institute of Scientific and Technical Information of China (English)
无
2008-01-01
This paper presents an investigation of inverter fault-tolerant operation for a permanent magnet synchronous motor (PMSM) direct torque control (DTC) system under various inverter faults. The performance of a faulty standard 6-switch inverter driven PMSM DTC system is analyzed. To avoid the loss or even disaster caused by the inverter faults, a topology-modified inverter with fault-tolerant capability is introduced, which is reconfigured as a 3-phase 4-switch inverter. The modeling of the 4-switch inverter is then analyzed and a novel DTC strategy with a unique nonlinear perpendicular flux observer and feedback compensation scheme is proposed for obtaining a continuous, disturbance-free drive system. The simulation and experimental results demonstrate that the proposed inverter fault-tolerant PMSM DTC system is able to operate stably and continuously with acceptable static and pretty good dynamic performance.
Inverter Anti-Islanding with Advanced Grid Support in Single- and Multi-Inverter Islands
Energy Technology Data Exchange (ETDEWEB)
Hoke, Andy
2016-08-16
As PV and other DER systems are connected to the grid at increased penetration levels, island detection may become more challenging for two reasons: 1. In islands containing many DERs, active inverter-based anti-islanding methods may have more difficulty detecting islands because each individual inverter's efforts to detect the island may be interfered with by the other inverters in the island. 2. The increasing numbers of DERs are leading to new requirements that DERs ride through grid disturbances and even actively try to regulate grid voltage and frequency back towards nominal operating conditions. These new grid support requirements may directly or indirectly interfere with anti-islanding controls. This report describes a series of tests designed to examine the impacts of both grid support functions and multi-inverter islands on anti-islanding effectiveness.
Invert muds : cost and disposal roadblocks
Energy Technology Data Exchange (ETDEWEB)
Garritty, N. [Engineered Drilling Solutions Inc., Calgary, AB (Canada)
2008-07-01
Since its inception, Engineered Drilling Solutions Incorporated (EDSI) has been focused on increasing drilling performance, increasing customer satisfaction, and decreasing drilling costs. Drilling fluid accounts for only 5 per cent of the cost to drill a well. It is necessary to look at how drilling fluid affects other aspects of drilling costs. Historically, the two main barriers to drilling with invert drilling fluids have been cost and disposal. EDSI's goal was to create an economical invert drilling fluid and develop an innovative way to dispose of the cuttings created while drilling it. This presentation discussed the costs and disposal roadblocks of invert muds. It provided a brief history of oil muds and the need for a new solution to the problem. Invert issues were identified. The presentation also discussed the removal of damaging components from the system and replacement of these materials with non-damaging alternatives which have allowed for the creation of a novel oil based drilling fluid formulation. The presentation discussed the development of 4G which was prepared with the use of a patent pending process using a colloid mill. The device achieved high levels of shear and, as a result, the fluid could be prepared to the consistency of paint. The 4G formulation was modified to 4GM in order to have a fluid that provided shear thinning at the bit for faster drilling, but that would gel up to provide for great hole cleaning. Shear thinning fluid also results in less fluid being lost over the shale shakers. 4GM was shown to enhance organophilic clay performance; significantly decrease maintenance; and decrease losses over the shaker. EDSI has also patented a solution that combines recycled tires and invert drill cuttings to create a product that replaces a portion of traditional aggregate in roads in order to offset the stresses on gravel road infrastructure as well as eliminating the waste going into landfills. figs.
Irby, Stefan M.; Phu, Andy L.; Borda, Emily J.; Haskell, Todd R.; Steed, Nicole; Meyer, Zachary
2016-01-01
There is much agreement among chemical education researchers that expertise in chemistry depends in part on the ability to coordinate understanding of phenomena on three levels: macroscopic (observable), sub-microscopic (atoms, molecules, and ions) and symbolic (chemical equations, graphs, etc.). We hypothesize this "level-coordination…
van Veldhoven, M; de Jonge, J; Broersen, S; Kompier, M; Meijman, T
2002-01-01
This cross-sectional questionnaire study presents a multi-level analysis on 2565 workers in 188 departments in 36 organizations in the Netherlands. A three-level model is used in which individual workers are nested within departments, which in turn are nested within organizations. Research questions
Institute of Scientific and Technical Information of China (English)
Jun Qian; Chengpu Liu; Shangqing Gong
2005-01-01
The effects of vacuum-induced coherence (VIC) on the properties of the absorption and gain of the probe field in an equispaced three-level ladder atomic system are investigated. It is found that lasing without inversion (LWI) is remarkably enhanced due to the effect of VIC in the case of the small incoherent pump rate.
Institute of Scientific and Technical Information of China (English)
PING Yun-Xia; LIU Lie; ZHANG Chao-Min; CHENG Ze
2011-01-01
Violations of Bell inequality, Cauchy-Schwarz inequality and entanglement in a two-mode three-level atomic system are investigated. It is shown that there are some states, which are entangled but do not violate Bell inequality in this system. Moreover, the relations of violations of Bell inequality, Cauchy-Schwarz inequality, and entanglement are discussed in detail.
Efficient three-wave mixing in a three-level atomic medium with an assisting microwave driven field
Institute of Scientific and Technical Information of China (English)
Li Jia-Hua; Luo Jin-Ming; Yang Wen-Xing; Zhan Zhi-Ming
2006-01-01
The potential for nonlinear conversion between two laser pulses in a three-level V-type medium with assistance of an auxiliary microwave resonant radiation is studied. The results show that microwave driven field can lead to the parametric generation of a new laser pulse with high conversion efficiency when a weak pump laser pulse is applied.
Chen, Jun Mian
2017-01-01
The extant literature on student migration flows generally focus on the traditional push-pull factors of migration at the individual level. Such a tendency excludes the broader levels affecting international student mobility. This paper proposes a hybrid of three levels of push-pull dynamics (micro-individual decision-making, meso-academic…
A scheme for conditional quantum phase gate via bimodal cavity and a Λ-type three-level atom
Institute of Scientific and Technical Information of China (English)
Cai Jian-Wu; Fang Mao-Fa; Liao Xiang-Ping; Zheng Xiao-Juan
2006-01-01
We propose a scheme to implement a two-qubit conditional quantum phase gate for the intracavity field via a single three-level Λ-type atom driven by two modes in a high-Q cavity. The quantum information is encoded on the Fock states of the bimodal cavity. The gate's averaged fidelity is expected to reach 99.8%.
Dong, Nianbo; Spybrook, Jessaca; Kelcey, Ben
2016-01-01
The purpose of this study is to propose a general framework for power analyses to detect the moderator effects in two- and three-level cluster randomized trials (CRTs). The study specifically aims to: (1) develop the statistical formulations for calculating statistical power, minimum detectable effect size (MDES) and its confidence interval to…
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 topo...
Long-lived entangled qudits in a trapped three-level ion beyond the Lamb-Dicke limit
Energy Technology Data Exchange (ETDEWEB)
Dermez, Rasim [Department of Physics, Afyon Kocatepe University, Afyonkarahisar 03200 (Turkey); Muestecaplioglu, Oezguer E [Department of Physics, Koc University, Sariyer, Istanbul 34450 (Turkey)], E-mail: dermez@aku.edu.tr
2009-01-15
Higher dimensional quantum entanglement in a trapped three-level ion interacting with two laser beams in {lambda} scheme is investigated beyond the Lamb-Dicke limit. It is shown that higher dimensional entanglement can be established in a single step, with a tunable dimensionality and duration via the Lamb-Dicke parameter.
Indian Academy of Sciences (India)
JAGHOURI HAKIMEH; SARBISHAEI MOHSEN; JAVIDAN KUROSH
2016-05-01
We solve the Nakajima–Zwanzig (NZ) non-Markovian master equation to study the dynamics of different types of three-level atomic systems interacting with bosonic Lorentzian reservoirs at zero temperature. Von Neumann entropy (S) is used to show the evolution of the degree of entanglement of the subsystems. The results presented are also compared with some recently published reports.
Online Variable Topology-Type Photovoltaic Grid-Connected Inverter
DEFF Research Database (Denmark)
Wu, Fengjiang; Sun, Bo; Duan, Jiandong
2015-01-01
and H-bridge inverter under the conditions of variable output voltage and power of the PV array. It is proved that, compared with the H-bridge inverter, the operation range of the cascaded inverter is wider, whereas the total loss is larger. Furthermore, a novel online variable topology-type grid...
Mobile Inverted Constructivism: Education of Interaction Technology in Social Media
Chai, Jia-Xiang; Fan, Kuo-Kuang
2016-01-01
The combination of social media and invert teaching is a new path to inverting interation technology education and reconstructing the curriculum of context. In this paper, based on the theory of constructivism learning, a model named Mobile Inverted Constructivism (MIC) is provided. Moreover, in view of the functional quality of social media in…
Hardware implementation of the quadruple inverted pendulum with single motor
Institute of Scientific and Technical Information of China (English)
LI Hongxing; WANG Jiayin; FENG Yanbin; GU Yundong
2004-01-01
Inverted pendulums are always used to verify some qualities and effect of certain control theory or method. Single or double inverted pendulum control system has been extensively studied for education and research purposes. However how to control a triple inverted pendulum is a difficult problem, which just a couple of control experts can solve including us. Undoubtedly, to implement controlling of a quadruple inverted pendulum is a very difficult problem, but we first successfully accomplished it using variable universe adaptive fuzzy control method in August, 2002. In this paper, a controller for a quadruple inverted pendulum is demonstrated using the variable universe adaptive fuzzy control theory.
Electronic Document Management Using Inverted Files System
Directory of Open Access Journals (Sweden)
Suhartono Derwin
2014-03-01
Full Text Available The amount of documents increases so fast. Those documents exist not only in a paper based but also in an electronic based. It can be seen from the data sample taken by the SpringerLink publisher in 2010, which showed an increase in the number of digital document collections from 2003 to mid of 2010. Then, how to manage them well becomes an important need. This paper describes a new method in managing documents called as inverted files system. Related with the electronic based document, the inverted files system will closely used in term of its usage to document so that it can be searched over the Internet using the Search Engine. It can improve document search mechanism and document save mechanism.
The invertible double of elliptic operators
DEFF Research Database (Denmark)
Booss-Bavnbek, Bernhelm; Lesch, Matthias; Zhu, Chaofeng
We construct a canonical invertible double for general first order elliptic differential operators over smooth compact manifolds with boundary and derive a natural formula for the Calderon projector which yields a generalization of the famous Cobordism Theorem. Assuming symmetric principal symbol...... of the tangential operator and unique continuation property (UCP) from the boundary, we obtain the continuous dependence of the Calderon projection on the data. The details of our results are available on arxiv arXiv:0803.4160 .......We construct a canonical invertible double for general first order elliptic differential operators over smooth compact manifolds with boundary and derive a natural formula for the Calderon projector which yields a generalization of the famous Cobordism Theorem. Assuming symmetric principal symbol...
Electronic Document Management Using Inverted Files System
Suhartono, Derwin; Setiawan, Erwin; Irwanto, Djon
2014-03-01
The amount of documents increases so fast. Those documents exist not only in a paper based but also in an electronic based. It can be seen from the data sample taken by the SpringerLink publisher in 2010, which showed an increase in the number of digital document collections from 2003 to mid of 2010. Then, how to manage them well becomes an important need. This paper describes a new method in managing documents called as inverted files system. Related with the electronic based document, the inverted files system will closely used in term of its usage to document so that it can be searched over the Internet using the Search Engine. It can improve document search mechanism and document save mechanism.
Solar Power Station Output Inverter Control Design
Bauer, J.; Lettl, J.
2011-01-01
The photovoltaic applications spreads in these days fast, therefore they also undergo great development. Because the amount of the energy obtained from the panel depends on the surrounding conditions, as intensity of the sun exposure or the temperature of the solar array, the converter must be connected to the panel output. The Solar system equipped with inverter can supply small loads like notebooks, mobile chargers etc. in the places where the supplying network is not present. Or the system...
Inverted temperature sequences: role of deformation partitioning
Grujic, D.; Ashley, K. T.; Coble, M. A.; Coutand, I.; Kellett, D.; Whynot, N.
2015-12-01
The inverted metamorphism associated with the Main Central thrust zone in the Himalaya has been historically attributed to a number of tectonic processes. Here we show that there is actually a composite peak and deformation temperature sequence that formed in succession via different tectonic processes. The deformation partitioning seems to the have played a key role, and the magnitude of each process has varied along strike of the orogen. To explain the formation of the inverted metamorphic sequence across the Lesser Himalayan Sequence (LHS) in eastern Bhutan, we used Raman spectroscopy of carbonaceous material (RSCM) to determine the peak metamorphic temperatures and Ti-in-quartz thermobarometry to determine the deformation temperatures combined with thermochronology including published apatite and zircon U-Th/He and fission-track data and new 40Ar/39Ar dating of muscovite. The dataset was inverted using 3D-thermal-kinematic modeling to constrain the ranges of geological parameters such as fault geometry and slip rates, location and rates of localized basal accretion, and thermal properties of the crust. RSCM results indicate that there are two peak temperature sequences separated by a major thrust within the LHS. The internal temperature sequence shows an inverted peak temperature gradient of 12 °C/km; in the external (southern) sequence, the peak temperatures are constant across the structural sequence. Thermo-kinematic modeling suggest that the thermochronologic and thermobarometric data are compatible with a two-stage scenario: an Early-Middle Miocene phase of fast overthrusting of a hot hanging wall over a downgoing footwall and inversion of the synkinematic isotherms, followed by the formation of the external duplex developed by dominant underthrusting and basal accretion. To reconcile our observations with the experimental data, we suggest that pervasive ductile deformation within the upper LHS and along the Main Central thrust zone at its top stopped at
Control Strategies of an Inverted Pendulum.
1981-09-01
AND PENDULUM --------- 12 2 FULL STATE VARIABLE FEEDBACK CONTROL SYSTEM - 31 3 CART QUARTER VIEW --------------------------- 34 4 CART TOP VIEW...system by moving the closed-loop poles to proper locations in the left-half plane. A feedback control system is one which attempts to main- tain a...pendulum angle oscillates on either side of zero. 30 x x x3 x 3 Figure 2. FULL STATE VARIABLE FEEDBACK CONTROL SYSTEM 31- IV. CONSTRUCTION OF INVERTED
High-efficiency Transformerless PV Inverter Circuits
Chen, Baifeng
2015-01-01
With worldwide growing demand for electric energy, there has been a great interest in exploring photovoltaic (PV) sources. For the PV generation system, the power converter is the most essential part for the efficiency and function performance. In recent years, there have been quite a few new transformerless PV inverters topologies, which eliminate the traditional line frequency transformers to achieve lower cost and higher efficiency, and maintain lower leakage current as well. With an ov...
Synthesizing Virtual Oscillators to Control Islanded Inverters
Energy Technology Data Exchange (ETDEWEB)
Johnson, Brian B.; Sinha, Mohit; Ainsworth, Nathan G.; Dorfler, Florian; Dhople, Sairaj V.
2016-08-01
Virtual oscillator control (VOC) is a decentralized control strategy for islanded microgrids where inverters are regulated to emulate the dynamics of weakly nonlinear oscillators. Compared to droop control, which is only well defined in sinusoidal steady state, VOC is a time-domain controller that enables interconnected inverters to stabilize arbitrary initial conditions to a synchronized sinusoidal limit cycle. However, the nonlinear oscillators that are elemental to VOC cannot be designed with conventional linear-control design methods. We address this challenge by applying averaging- and perturbation-based nonlinear analysis methods to extract the sinusoidal steady-state and harmonic behavior of such oscillators. The averaged models reveal conclusive links between real- and reactive-power outputs and the terminal-voltage dynamics. Similarly, the perturbation methods aid in quantifying higher order harmonics. The resultant models are then leveraged to formulate a design procedure for VOC such that the inverter satisfies standard ac performance specifications related to voltage regulation, frequency regulation, dynamic response, and harmonic content. Experimental results for a single-phase 750 VA, 120 V laboratory prototype demonstrate the validity of the design approach. They also demonstrate that droop laws are, in fact, embedded within the equilibria of the nonlinear-oscillator dynamics. This establishes the backward compatibility of VOC in that, while acting on time-domain waveforms, it subsumes droop control in sinusoidal steady state.
Energy Technology Data Exchange (ETDEWEB)
Agamy, Mohammed; Harfman-Todorovic, Maja; Elasser, Ahmed; Essakiappan, Somasundaram
2013-03-01
Photovoltaic architectures with distributed power electronics provide many advantages in terms of energy yield as well as system level optimization. As the power level of the solar farm increases it becomes more beneficial to increase the dc collection network voltage, which requires the use of power devices with higher voltage ratings, and thus making the design of efficient, low cost, distributed power converters more challenging. In this paper a simple partial power converter topology is proposed. The topology is implemented using a three-level switching cell, which allows the use of semiconductor devices with lower voltage rating; thus improving design and performance and reducing converter cost. This makes the converters suitable for use for medium to high power applications where dc-link voltages of 600V~1kV may be needed without the need for high voltage devices. Converter operation and experimental results are presented for two partial power circuit variants using three-level switching cells.
Institute of Scientific and Technical Information of China (English)
HU Wen-Hui; YUAN Kai-Jun; HAN Yong-Chang; Shu Chuang-Cun; CONG Shu-Lin
2007-01-01
The Autler-Townes (AT) splitting in femtosecond photoelectron spectrum of three-level Lii molecules is theoretically investigated using time-dependent quantum wave packet method. With proper femtosecond laser pulses, three peaks of the AT splitting can be observed in the photoelectron spectrum. The AT splitting stems from rapid Rabi oscillation caused by intense ultrashort laser pluses. The effects of laser parameters on the molecular ionization dynamics are also discussed.
DEFF Research Database (Denmark)
Pouresmaeil, Edris; Montesinos-Miracle, Daniel; Gomis-Bellmunt, Oriol
2011-01-01
This paper presents a control strategy of multilevel converters for integration of renewable energy resources into power grid. The proposed technique provides compensation for active, reactive, and harmonic current components of grid-connected loads. A three-level H-bridge converter is proposed a...... (THD) of grid current through Matlab/Simulink under proposed operating conditions. © 2011 EPE Association - European Power Electr....
Institute of Scientific and Technical Information of China (English)
PING Yun-Xia; CHENG Ze
2007-01-01
Continuous variable entanglement and violation of Bell inequality for two modes are investigated in a three-level cascade atomic system. Entanglement of the system is demonstrated according to the entanglement criterion [Phys. Rev. Lett. 84 (2000) 2722]. Violation of Bell inequality is studied within the framework of a quantum theory of multiwave mixing. It is shown that there are some states that are entangled but do not violate the Bell inequality.
Photon counting statistics of V-type three-level systems:Effects of the field fluctuations
Institute of Scientific and Technical Information of China (English)
彭勇刚; 郑雨军
2015-01-01
We investigate the infl uence of the filed fl uctuations to the emission photons of V three-level systems. The emission intensity I and Mandel’s Q parameter show stochastic resonance with respect to the pure dephasing constant γp. The amplitude fl uctuation of the field causes the systems lose their coherence, on the other way, the amplitude fl uctuation provides a new interference way for the systems. The quantum beats are shown in the orthogonal system.
Nonclasssical Properties in Two-Mode Fields Resonantly Interacting with a Three-Level [Ⅰ]-Type Atom
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
Some noclassical properties in electromagnetic Reid are investigated for the interaction of two-modes initially taken in coherent-state representation with the three-level [Ⅰ]-type atom, such as squeezing properties and violation of the Cauchy-Schwartz inequality. The enhancement of Geld squeezing is found by selective atomic measurement. The Cauchy-Schwartz inequality is violated by the application of the classical Geld followed by detection in excited state.
Institute of Scientific and Technical Information of China (English)
XU Jing-Bo; ZOU Xu-Bo; GAO Xiao-Chun; FU Jian
2004-01-01
With the help of an SU(3) dynamical algebraic structure, we find an exact solution of the Milburn equation for the system of a three-level atom in the Ξ configuration interacting with one quantized field mode with arbitrary detuning. The exact solution is then used to discuss the influence of the intrinsic decoherence on the nonclassical properties of the system, such as collapes and revivals of the atomic populations, oscillations of the photon number distribution, and squeezing of the radiation field.
DEFF Research Database (Denmark)
Choi, Ui-Min; Blaabjerg, Frede; Lee, Kyo-Beum
2015-01-01
The centralized topology with three-level inverters are widely used in photovoltaic (PV) systems due to their less installation costs and complexity. However, the common maximum power point tracking (MPPT) is a disadvantage of the centralized topology particularly under the partial shading...... and panel mismatch conditions. In this system, if PV modules are separately connected to the split capacitor voltage, the MPPT efficiency can be improved by the proposed control strategy. By the proposed method, the two capacitor voltages can be controlled asymmetrically to perform the separate MPPTs...
Design of inverters for the PHOTONERGY project
Energy Technology Data Exchange (ETDEWEB)
NONE
2003-08-01
The PHOTONERGY project (the former SolcelleInverter project) was initiated on the 1st of September 2001, with a state-of-the-art analysis, which concluded into specifications. Based on this 23 topologies were analyzed in for efficiencies. The results from this analysis was five candidates which all showed a somewhat good efficiency. These five topologies were in further investigated by means of an initial design-iteration and simulations. Two different solutions were picked up in due to their high efficiency and low cost. 1. The standard full-bridge phase shifted DC/DC converter together with a standard DC/AC inverter, 2. A modified version of the novel Shimizu topology. A patent is pending on this modified version. These two inverters are in this document developed and made ready for prototyping. This includes design and selection of reactive- and switching-components, e.g. filter- and bulk-capacitors, low- and high-frequency inductors, high frequency transformers, MOSFETs and diodes. The design of auxiliary circuits is also included, e.g. gate drivers for the MOSFETs, measuring circuits for the grid-current and -voltage, PV-module-current and voltage, protection circuits, hardware near controllers and finally a switch mode power supply. However, the design of the various controllers, except the hardware near PV-current controller for the full bridge phase shifted converter, is not documented in this report but will come later on. This includes all controllers, e.g. maximum power point tracking for the PV-module, utility grid current controller, DC-link voltage controller, phase locked loops, and detection of islanding operation. All of these control loops are to be implemented in a micro-controller. (au)
Novel T-Z source inverter with high voltage gain and reduced transformer turn ratio
DEFF Research Database (Denmark)
Mostaan, Ali; Sharifi Malfejani, Saeed; Soltani, Mohsen
2015-01-01
Novel voltage source inverter based on the Z source inverter structure is introduced in this paper. In this new inverter, two inductors of the impedance network in conventional Z source inverter are replaced with two transformers or coupled inductors, but unlike the T-Z source inverter that it's ...... cost. The proposed inverter is analyzed in steady state and its voltage gain is obtained. The performance of the proposed inverter is verified with simulation results using the MATLAB/SIMULINK software....
Generalized SVPWM Algorithm for Two Legged Three Phase Multilevel Inverter
Directory of Open Access Journals (Sweden)
Devisree Sasi
2013-07-01
Full Text Available This paper establishes the inherent fractal structure in the space vector representation of two legged three phase multilevel inverters. The established fractal structure is utilized to propose a generalized algorithm for space vector PWM generation for two legged multilevel inverters. The voltage space vectors of higher level inverters can be generated from the voltage space vectors of equivalent 2-level inverter. The proposed algorithm can be easily extended to n-level inverters without any computational complexity and it doesn’t use any look up table for sector identification. The paper explains the proposed method for 5-level inverter and simulation results are presented for 2-level, 3-level and 5-level configurations in MATLAB/SIMULINK.
Review of multilevel voltage source inverter topologies and control schemes
Energy Technology Data Exchange (ETDEWEB)
Colak, Ilhami [Department of Electrical Education, Faculty of Technical Education, Gazi University, Besevler, Ankara 06500 (Turkey); Kabalci, Ersan, E-mail: kabalci@nevsehir.edu.t [Department of Technical Programs, Vocational Collage of Haci Bektas, Nevsehir University, Hacibektas, Nevsehir 50800 (Turkey); Bayindir, Ramazan [Department of Electrical Education, Faculty of Technical Education, Gazi University, Besevler, Ankara 06500 (Turkey)
2011-02-15
In this study, the most common multilevel inverter topologies and control schemes have been reviewed. Multilevel inverter topologies (MLIs) are increasingly being used in medium and high power applications due to their many advantages such as low power dissipation on power switches, low harmonic contents and low electromagnetic interference (EMI) outputs. The selected switching technique to control the inverter will also have an effective role on harmonic elimination while generating the ideal output voltage. Intensive studies have been performed on carrier-based, sinusoidal, space vector and sigma delta PWM methods in open loop control of inverters. The selection of topology and control techniques may vary according to power demands of inverter. This paper and review results constitute a useful basis for matching of inverter topology and the best control scheme according to various application areas.
Multi-cell Trans-z-source Inverters
DEFF Research Database (Denmark)
Li, Ding; Loh, Poh Chiang; Zhu, Miao;
2011-01-01
Z-source inverter is a single-stage inverter with added voltage-boost capability for complementing the usual voltage-buck operation of a traditional voltage-source inverter. And it embedded with two capacitors and two inductors in its impedance network. As long as magnetically coupling components...... embedded within the network, the developed z-source inverters shows additional merits such as higher boosting ratio or using less passive device. The trans-z-source inverter with one transformer and one capacitor is reported recently. To increase the boosting ratio further a cascaded concept is proposed...... with adopting multi-winding transformer which provides a possibility for this paper to using coupled inductor instead of multi-winding transformer and remains the same voltage gain as cascaded trans-z-source inverter. Theoretical analysis for explaining these operating features has already been discussed before...
An Inverted Curriculum for CS1
DEFF Research Database (Denmark)
Caspersen, Michael Edelgaard
2003-01-01
present and discuss the inverted curriculum for our introductory object-oriented programming course, and our experiences from teaching this course for four years. We identify four levels for the systematic construction of programs, and the structure of our programming course is based on these four levels......Most introductory programming courses and textbooks are structured according to the constructs of the adopted programming language and not on the basis of those language independent concepts, principles and techniques of programming that the students should master by the end of the course. We...
MPPT algorithm for voltage controlled PV inverters
DEFF Research Database (Denmark)
Kerekes, Tamas; Teodorescu, Remus; Liserre, Marco;
2008-01-01
This paper presents a novel concept for an MPPT that can be used in case of a voltage controlled grid connected PV inverters. In case of single-phase systems, the 100 Hz ripple in the AC power is also present on the DC side. Depending on the DC link capacitor, this power fluctuation can be used t...... to track the MPP of the PV array, using the information that at MPP the power oscillations are very small. In this way the algorithm can detect the fact that the current working point is at the MPP, for the current atmospheric conditions....
Linear control of the flywheel inverted pendulum.
Olivares, Manuel; Albertos, Pedro
2014-09-01
The flywheel inverted pendulum is an underactuated mechanical system with a nonlinear model but admitting a linear approximation around the unstable equilibrium point in the upper position. Although underactuated systems usually require nonlinear controllers, the easy tuning and understanding of linear controllers make them more attractive for designers and final users. In a recent paper, a simple PID controller was proposed by the authors, leading to an internally unstable controlled plant. To achieve global stability, two options are developed here: first by introducing an internal stabilizing controller and second by replacing the PID controller by an observer-based state feedback control. Simulation and experimental results show the effectiveness of the design.
On the invertibility of elementary operators
Boudi, Nadia; Bračič, Janko
2013-01-01
Let $\\mathscr{X}$ be a complex Banach space and $\\mathcal{L}(\\mathscr{X})$ be the algebra of all bounded linear operators on $\\mathscr{X}$. For a given elementary operator $\\Phi$ of length $2$ on $\\mathcal{L}(\\mathscr{X})$, we determine necessary and sufficient conditions for the existence of a solution of the equation ${\\rm X} \\Phi=0$ in the algebra of all elementary operators on $\\mathcal{L}(\\mathscr{X})$. Our approach allows us to characterize some invertible elementary operators of length...
Directory of Open Access Journals (Sweden)
Jiraporn Janwised
2014-01-01
Full Text Available We introduce a new technique, a three-level average linear-implicit finite difference method, for solving the Rosenau-Burgers equation. A second-order accuracy on both space and time numerical solution of the Rosenau-Burgers equation is obtained using a five-point stencil. We prove the existence and uniqueness of the numerical solution. Moreover, the convergence and stability of the numerical solution are also shown. The numerical results show that our method improves the accuracy of the solution significantly.
Narrowband Biphoton Generation with Four-Wave Mixing in a Far-Detuning Three-Level System
Institute of Scientific and Technical Information of China (English)
CHEN Peng; ZHOU Shu-Yu; XU Zhen; DUAN Ya-Fan; CUI Guo-Dong; HONG Tao; WANG Yu-Zhu
2011-01-01
Non-classical paired photons are generated by a four-wave mixing process in a far-detuning three-level system with cold atoms.A violation of the Cauchy-Schwartz inequality of a factor of 310 is observed.This phenomenon shows that paired photons have a non-classical correlation. The experimental results are compared with theoretical results obtained using perturbation theory.The oscillation frequencies of the two-photon intensity correlation functions are in reasonable agreement with the effective Rabi frequencies of the coupling laser.However,we find that the dephasing rates (or decay rates) observed are far larger than the theoretical values.
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...... 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....
Institute of Scientific and Technical Information of China (English)
Zhu Ai-Dong; Zhang Shou
2004-01-01
The dynamical property of a cascade three-level atom is investigated in the condition of atomic motion. The influence of atomic motion on the population and dipole squeezing is discussed. The results show that atomic motion makes the amplitude of atomic population be steady and increasing the parameter ep which denotes the atomic motion and the structure of field mode can shorten the period of collapse-revivals. By choosing an appropriate paramenter ep, we can obtain a dipole squeezed atom of long standing.
Hawaiian Electric Advanced Inverter Test Plan - Result Summary
Energy Technology Data Exchange (ETDEWEB)
Hoke, Anderson; Nelson, Austin; Prabakar, Kumaraguru; Nagarajan, Adarsh
2016-10-14
This presentation is intended to share the results of lab testing of five PV inverters with the Hawaiian Electric Companies and other stakeholders and interested parties. The tests included baseline testing of advanced inverter grid support functions, as well as distribution circuit-level tests to examine the impact of the PV inverters on simulated distribution feeders using power hardware-in-the-loop (PHIL) techniques. hardware-in-the-loop (PHIL) techniques.
Research on Cascade Double Г-CL Resonant Inverter
Institute of Scientific and Technical Information of China (English)
ZhuJianhua; LuoFanglin
2004-01-01
A cascade double Г-CL current source resonant inverter (CSRI) is proposed in this paper, which overcomes the limitations of the conventional two or three energy-storage elements resonant inverters. Comparing with the counterparts, the novel inverter has larger current transfer gain with smooth waveforms. The simulation process is manipulated on the basis of the state-space averaging approach. The power transfer efficiency is studied in detail. Finally. the theoretical analysis is verified with the simulative and testing results.
Five-level Z-source diode-clamped inverter
DEFF Research Database (Denmark)
Gao, F.; Loh, Poh Chiang; Blaabjerg, Frede
2010-01-01
-source inverter are introduced here for operating the proposed inverter with voltage buck–boost energy conversion ability and five-level phase voltage switching. These characteristic features are in fact always ensured at the inverter terminal output by simply adopting a properly designed carrier modulation...... scheme, which always inserts two partial shoot-through states per half carrier cycle for smooth balanced operation. Theoretical findings and practical issues identified are eventually verified by constructing a scaled down laboratory prototype for testing....
Finishing report for the 'SolcelleInverter' project
Energy Technology Data Exchange (ETDEWEB)
Boekhoej Kjaer, S.
2005-03-01
The main objective for this research project was to develop an inverter for the AC module, where one PV module is equipped with its own dedicated inverter, and connected to the grid. A topology, among many different candidates, has been selected, based on analysis's. The inverter has been optimized in respect to cost, reliability, and efficiency, and a prototype has been build. (au)
Linear Maps Preserving Invertibility or Related Spectral Properties
Institute of Scientific and Technical Information of China (English)
Jin Chuan HOU; Peter SEMRL
2003-01-01
We survey some recent results on linear maps on operator algebras that preserve invert-ibility. We also consider related problems such as the problem of the characterization of linear mapspreserving spectrum, various parts of spectrum, spectral radius, quasinilpotents, etc. We present someresults on elementary operators and additive operators preserving invertibility or related properties. Inparticular, we give a negative answer to a problem posed by Gao and Hou on characterizing spectrum-preserving elementary operators. Several open problems are also mentioned.
Multilayer control for inverters in parallel operation without signal interconnection
DEFF Research Database (Denmark)
Hua, Ming; Hu, Haibing; Xing, Yan;
2011-01-01
by adjusting the phase and amplitude of the output voltage respectively. The second layer is to compensate the droop voltage caused by the droop control and thus improve the load regulation performance of the inverter. The third layer limits the phase deviation between the inverter and the shared ac bus......A multilayer control is proposed for inverters with wireless parallel operation in this paper. The control is embedded in every inverter respectively and consists of three layers. The first layer is based on an improved droop method, which shares the active and reactive power in each module...
Optimized Pulse Width Modulation for transformerless active-NPC inverters
DEFF Research Database (Denmark)
Achilladelis, Nikolaos; Koutroulis, Eftichios; Blaabjerg, Frede
2014-01-01
The transformerless DC/AC inverter topologies are employed in Photovoltaic systems in order to improve the power conversion efficiency, power density and cost. The Active-Neutral Point Clamped (Active-NPC) transformerless inverters have the advantage of achieving better thermal balance among...... their power semiconductors. In this paper, a new modulation technique is proposed for optimally controlling the power switches employed in transformerless Active-NPC inverters. The design results demonstrate that compared to the existing PWM strategies, using the proposed method results in lower total power...... losses and significantly better distribution of the power losses among the semiconductors of the Active-NPC inverter....