This paper addresses the switching transients in multibranch thyristor-switched capacitors (TSCs). The current transients following the addition of a branch to a group of already connected ones are analyzed. Expressions for both its fundamental and its oscillatory components are given in terms of the power network voltage, frequency, short-circuit level, and the switching angle. The relations include also the compensator parameters such as its total reactive power rating, total number of branches, the number of already connected branches, and the initial voltage on the capacitor involved in the switching transient. An expression for the distortion of the supply current is also given. A minimization procedure is presented for identifying the optimal switching angle leading to the least magnitude of the oscillatory current. Switching when the instantaneous supply voltage is equal to the initial voltage will result in the least oscillatory current only in the two special cases of a single-branch compensator, or in the switching of the first branch of a multi-branch TSC. The effect of both the total number of branches and the branch switching steps on the oscillatory current and on the optimal switching angle is also discussed. The advantage of the suggested procedure is demonstrated by investigating several case studies.
{"title":"Analysis and Minimization of the Oscillatory Currents in Multibranch Thyristor-Switched Capacitors","authors":"M. Saied","doi":"10.1155/2012/643716","DOIUrl":"https://doi.org/10.1155/2012/643716","url":null,"abstract":"This paper addresses the switching transients in multibranch thyristor-switched capacitors (TSCs). The current transients following the addition of a branch to a group of already connected ones are analyzed. Expressions for both its fundamental and its oscillatory components are given in terms of the power network voltage, frequency, short-circuit level, and the switching angle. The relations include also the compensator parameters such as its total reactive power rating, total number of branches, the number of already connected branches, and the initial voltage on the capacitor involved in the switching transient. An expression for the distortion of the supply current is also given. A minimization procedure is presented for identifying the optimal switching angle leading to the least magnitude of the oscillatory current. Switching when the instantaneous supply voltage is equal to the initial voltage will result in the least oscillatory current only in the two special cases of a single-branch compensator, or in the switching of the first branch of a multi-branch TSC. The effect of both the total number of branches and the branch switching steps on the oscillatory current and on the optimal switching angle is also discussed. The advantage of the suggested procedure is demonstrated by investigating several case studies.","PeriodicalId":412593,"journal":{"name":"Advances in Power Electronic","volume":"2012 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129647724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents an investigation of voltage-and-frequency-(VF-) based battery energy storage system (BESS) controller used in micro grid for analyzing the optimum capability of plant. Microgrid is formed by using three hydropower plants feeding three-phase four-wire load. The proposed controller is used for load balancing, harmonic elimination, load leveling, and neutral current compensation. The proposed BESS controller permits the selection of an optimum voltage level of battery and allows independent current control of each phase. The main emphasis is given on maintaining constant voltage and frequency within the micro grid during transient conditions. Micro grid with power plant and its controller is modeled in MATLAB/Simulink using Power System Blockset (PSB) toolboxes.
研究了基于电压频率的电池储能系统(BESS)控制器在微电网中的应用，以分析电站的最优发电能力。微电网由3座水电站馈电三相四线制负荷组成。该控制器用于负载平衡、谐波消除、负载均衡和中性点电流补偿。所提出的BESS控制器允许选择电池的最佳电压水平，并允许每个相位的独立电流控制。主要的重点是在瞬态状态下保持微电网内的恒定电压和频率。利用电力系统块集(power System Blockset, PSB)工具箱，在MATLAB/Simulink中对带电厂的微电网及其控制器进行建模。
{"title":"Analysis of a Microgrid under Transient Conditions Using Voltage and Frequency Controller","authors":"M. Jain, Sushma Gupta, D. Masand, G. Agnihotri","doi":"10.1155/2012/208231","DOIUrl":"https://doi.org/10.1155/2012/208231","url":null,"abstract":"This paper presents an investigation of voltage-and-frequency-(VF-) based battery energy storage system (BESS) controller used in micro grid for analyzing the optimum capability of plant. Microgrid is formed by using three hydropower plants feeding three-phase four-wire load. The proposed controller is used for load balancing, harmonic elimination, load leveling, and neutral current compensation. The proposed BESS controller permits the selection of an optimum voltage level of battery and allows independent current control of each phase. The main emphasis is given on maintaining constant voltage and frequency within the micro grid during transient conditions. Micro grid with power plant and its controller is modeled in MATLAB/Simulink using Power System Blockset (PSB) toolboxes.","PeriodicalId":412593,"journal":{"name":"Advances in Power Electronic","volume":"178 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124429576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper describes and demonstrates the principle and efficacy of a novel direct current fault interruption scheme using a reactor in series with a controlled rectifier and a conventional AC circuit breaker. The presence of the series reactor limits the capacitive discharge current from the DC filter capacitor at the output terminals of the phase-controlled rectifier. In addition, the series reactor along with the filter capacitor forms an underdamped series RLC circuit which forces the fault current to oscillate about zero. This synthetic alternating current can then be interrupted using a conventional AC circuit breaker. The selection criteria for the series reactor and overcurrent protection are presented as well. Using the proposed scheme for an example case, a DC fault current magnitude is reduced from 56 kA to 14 kA, while the interruption time is reduced from 44 ms to 25 ms.
{"title":"Interrupting Short-Circuit Direct Current Using an AC Circuit Breaker in Series with a Reactor","authors":"S. Kulkarni, S. Santoso","doi":"10.1155/2012/805958","DOIUrl":"https://doi.org/10.1155/2012/805958","url":null,"abstract":"This paper describes and demonstrates the principle and efficacy of a novel direct current fault interruption scheme using a reactor in series with a controlled rectifier and a conventional AC circuit breaker. The presence of the series reactor limits the capacitive discharge current from the DC filter capacitor at the output terminals of the phase-controlled rectifier. In addition, the series reactor along with the filter capacitor forms an underdamped series RLC circuit which forces the fault current to oscillate about zero. This synthetic alternating current can then be interrupted using a conventional AC circuit breaker. The selection criteria for the series reactor and overcurrent protection are presented as well. Using the proposed scheme for an example case, a DC fault current magnitude is reduced from 56 kA to 14 kA, while the interruption time is reduced from 44 ms to 25 ms.","PeriodicalId":412593,"journal":{"name":"Advances in Power Electronic","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126076905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wide-input, low-voltage, and high-current applications are addressed. A single-ended isolated topology which improves the power efficiency, reduces both switching and conduction losses, and heavily lowers the system cost is presented. During each switching cycle, the transformer core reset is provided. The traditional tradeoff between the maximum allowable duty-cycle and the reset voltage is avoided and the off-voltage of active switches is clamped to the input voltage. Therefore, the system cost is heavily reduced and the converter is well suited for wide-input applications. Zero-voltage switching is achieved for active switches, and the power efficiency is greatly improved. In the output mesh, an inductor is included making the converter suitable for high-current, low-voltage applications. Since the active clamp forward converter is the closest competitor of the proposed converter, a comparison is provided as well. In this paper, the steady-state and small-signal analysis of the proposed converter is presented. Design examples are provided for further applications. Simulation and experimental results are shown to validate the great advantages brought by the proposed topology.
{"title":"A High-Efficiency, Low-Cost Solution for On-Board Power Converters","authors":"V. Boscaino, G. Capponi","doi":"10.1155/2012/259756","DOIUrl":"https://doi.org/10.1155/2012/259756","url":null,"abstract":"Wide-input, low-voltage, and high-current applications are addressed. A single-ended isolated topology which improves the power efficiency, reduces both switching and conduction losses, and heavily lowers the system cost is presented. During each switching cycle, the transformer core reset is provided. The traditional tradeoff between the maximum allowable duty-cycle and the reset voltage is avoided and the off-voltage of active switches is clamped to the input voltage. Therefore, the system cost is heavily reduced and the converter is well suited for wide-input applications. Zero-voltage switching is achieved for active switches, and the power efficiency is greatly improved. In the output mesh, an inductor is included making the converter suitable for high-current, low-voltage applications. Since the active clamp forward converter is the closest competitor of the proposed converter, a comparison is provided as well. In this paper, the steady-state and small-signal analysis of the proposed converter is presented. Design examples are provided for further applications. Simulation and experimental results are shown to validate the great advantages brought by the proposed topology.","PeriodicalId":412593,"journal":{"name":"Advances in Power Electronic","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129988222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The ferroresonance or nonlinear resonance is a complex phenomenon, which may cause overvoltage in the electrical power system and endangers the system reliability and operation. The ability to predict the ferroresonance in the transformer depends on the accuracy of the transformer model used. In this paper, the effect of the new suggested ferroresonance limiter on the control of the chaotic ferroresonance and duration of chaotic transients in a potential transformer including nonlinear core losses is studied. To study the proposed ferroresonance limiter, a single phase 100 VA, 275 kV potential transformer is simulated. The magnetization characteristic of the potential transformer is modeled by a single-value two-term polynomial. The core losses are modeled by third order power series in terms of voltage and include core nonlinearities. The simulation results show that the ferroresonance limiter has a considerable effect on the ferroresonance overvoltage.
{"title":"Resistive Ferroresonance Limiter for Potential Transformers","authors":"H. Radmanesh, G. Gharehpetian, H. Fathi","doi":"10.1155/2012/529178","DOIUrl":"https://doi.org/10.1155/2012/529178","url":null,"abstract":"The ferroresonance or nonlinear resonance is a complex phenomenon, which may cause overvoltage in the electrical power system and endangers the system reliability and operation. The ability to predict the ferroresonance in the transformer depends on the accuracy of the transformer model used. In this paper, the effect of the new suggested ferroresonance limiter on the control of the chaotic ferroresonance and duration of chaotic transients in a potential transformer including nonlinear core losses is studied. To study the proposed ferroresonance limiter, a single phase 100 VA, 275 kV potential transformer is simulated. The magnetization characteristic of the potential transformer is modeled by a single-value two-term polynomial. The core losses are modeled by third order power series in terms of voltage and include core nonlinearities. The simulation results show that the ferroresonance limiter has a considerable effect on the ferroresonance overvoltage.","PeriodicalId":412593,"journal":{"name":"Advances in Power Electronic","volume":"96 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130321216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A dynamic voltage restorer (DVR) with no energy storage is studied. By using a matrix converter instead of the conventional AC/DC/AC converters, elimination of the DC-link capacitor is possible. The switching algorithm of matrix converter is the space vector modulation. There are different compensation algorithms to control the conventional DVR. These methods have been analyzed in this paper for the proposed matrix-converter-based DVR. A deep analysis through different diagrams would show the advantages or disadvantages of each compensation method. Equations for all methods are derived, and the characteristics of algorithms are compared with each other.
{"title":"Comparative Studies of Different Control Strategies of a Dynamic Voltage Restorer Based on Matrix Converter","authors":"A. Shabanpour, A. Seifi","doi":"10.1155/2012/327186","DOIUrl":"https://doi.org/10.1155/2012/327186","url":null,"abstract":"A dynamic voltage restorer (DVR) with no energy storage is studied. By using a matrix converter instead of the conventional AC/DC/AC converters, elimination of the DC-link capacitor is possible. The switching algorithm of matrix converter is the space vector modulation. There are different compensation algorithms to control the conventional DVR. These methods have been analyzed in this paper for the proposed matrix-converter-based DVR. A deep analysis through different diagrams would show the advantages or disadvantages of each compensation method. Equations for all methods are derived, and the characteristics of algorithms are compared with each other.","PeriodicalId":412593,"journal":{"name":"Advances in Power Electronic","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123895204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper investigates the numerical issue of a discrete-time induction-motor emulator implementation. The stability analysis of the finite-word-length implementation shows a coupling between required word length and the sample rate. We propose specific guidelines to analyze this coupling and to estimate the required data word length for both signals and coefficients of the model. To respect algorithm requirements, an FPGA-based implementation was used for architecture development. The direct torque control is implemented to verify in real time the AC-motor emulator prototype.
{"title":"FPGA-Based Fixed Point Implementation of a Real-Time Induction Motor Emulator","authors":"L. Charaabi","doi":"10.1155/2012/409671","DOIUrl":"https://doi.org/10.1155/2012/409671","url":null,"abstract":"This paper investigates the numerical issue of a discrete-time induction-motor emulator implementation. The stability analysis of the finite-word-length implementation shows a coupling between required word length and the sample rate. We propose specific guidelines to analyze this coupling and to estimate the required data word length for both signals and coefficients of the model. To respect algorithm requirements, an FPGA-based implementation was used for architecture development. The direct torque control is implemented to verify in real time the AC-motor emulator prototype.","PeriodicalId":412593,"journal":{"name":"Advances in Power Electronic","volume":"340 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130081515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper is concerned with performance of the current shaping network in Average Current Mode (ACM) Active Power Factor Correction (APFC) systems. Theoretical expressions for the ripple components are derived. Then, ripple interaction and impact on the current loop reference signal are investigated. A modification of the controller network is suggested that results in an improved Total Harmonic Distortion (THD). Design guidelines are suggested. The theoretical predictions were validated by simulation.
{"title":"Controller Design Considerations for ACM APFC Systems","authors":"A. Abramovitz","doi":"10.1155/2012/286861","DOIUrl":"https://doi.org/10.1155/2012/286861","url":null,"abstract":"This paper is concerned with performance of the current shaping network in Average Current Mode (ACM) Active Power Factor Correction (APFC) systems. Theoretical expressions for the ripple components are derived. Then, ripple interaction and impact on the current loop reference signal are investigated. A modification of the controller network is suggested that results in an improved Total Harmonic Distortion (THD). Design guidelines are suggested. The theoretical predictions were validated by simulation.","PeriodicalId":412593,"journal":{"name":"Advances in Power Electronic","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126610290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An isolated bidirectional full-bridge DC-DC converter with flyback snubber for supplying a resistive load is simulated and experimentally verified. The DC-DC converter for high conversion ratio, high output power, and soft start-up capability is presented in this paper. The circuit consists of a capacitor, a diode, and a flyback converter. These components help to clamp the voltage spikes caused by the current difference between the current fed inductor and leakage inductance of the isolation transformer. The switches are operated by soft-switching technology. The suppression of inrush current which is usually found in the boost mode start-up transition is presented here. The simulated and experimental results for output voltage, output current, and power for both buck and boost modes are presented.
{"title":"Embedded Controlled Isolated Bidirectional Full-Bridge DC-DC Converter with Flyback Snubber","authors":"D. Kirubakaran, Rama Reddy Sathi","doi":"10.1155/2012/730473","DOIUrl":"https://doi.org/10.1155/2012/730473","url":null,"abstract":"An isolated bidirectional full-bridge DC-DC converter with flyback snubber for supplying a resistive load is simulated and experimentally verified. The DC-DC converter for high conversion ratio, high output power, and soft start-up capability is presented in this paper. The circuit consists of a capacitor, a diode, and a flyback converter. These components help to clamp the voltage spikes caused by the current difference between the current fed inductor and leakage inductance of the isolation transformer. The switches are operated by soft-switching technology. The suppression of inrush current which is usually found in the boost mode start-up transition is presented here. The simulated and experimental results for output voltage, output current, and power for both buck and boost modes are presented.","PeriodicalId":412593,"journal":{"name":"Advances in Power Electronic","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122172693","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The basic power quality problems in the distribution network are voltage sag (dip), voltage flickering, and the service interruptions. STATCOM is a Flexible AC Transmission Systems (FACTS) technology device which can independently control the flow of reactive power. This paper presents the simulation and analysis of a STATCOM for voltage dip and voltage flickering mitigation. Simulations are carried out in MATLAB/Simulink to validate the performance of the STATCOM. A comparison between the six-pulse inverter and the five-level diode-clamped inverter is carried out for the performance of 66/11 KV distribution system.
{"title":"Mitigation of Voltage Dip and Voltage Flickering by Multilevel D-STATCOM","authors":"M. Ballal, H. Suryawanshi, T. V. Reddy","doi":"10.1155/2012/871652","DOIUrl":"https://doi.org/10.1155/2012/871652","url":null,"abstract":"The basic power quality problems in the distribution network are voltage sag (dip), voltage flickering, and the service interruptions. STATCOM is a Flexible AC Transmission Systems (FACTS) technology device which can independently control the flow of reactive power. This paper presents the simulation and analysis of a STATCOM for voltage dip and voltage flickering mitigation. Simulations are carried out in MATLAB/Simulink to validate the performance of the STATCOM. A comparison between the six-pulse inverter and the five-level diode-clamped inverter is carried out for the performance of 66/11 KV distribution system.","PeriodicalId":412593,"journal":{"name":"Advances in Power Electronic","volume":"171 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123133019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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