Experimental Investigation of Decoupled Discontinuous PWM Strategies in Open-End Winding Induction Motor Supplied by a Common DC-link

© 2023 IEEE. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1109/JESTPE.2023.3258799Currently, open-end winding induction motors fed by a dual inverter (OEWIM-DI) present an innovative approach to enhance the performance of modern electric drive systems, such as electrical vehicles and electric aircraft applications. However, the DI topology requires a proper switching control strategy to enable the OEWIM drive to fully achieve its performance. This work aims to investigate experimentally the impact of different decoupled discontinuous pulsewidth modulation (DDPWM) control strategies on the performance of the OEWIM-DI supplied by a common dc-link. The criteria performances adopted in this study are: 1) the total harmonic distortion (THD) of the current and voltage; 2) the zero sequence voltage (ZSV); 3) the common mode voltage (CMV); and 4) the DI losses. The various DDPWM control schemes for the 1.5-kW OEWIM-DI motor drive are implemented on a dSPACE 1104 board, and the results are compared with the popular and widely used space-vector PWM (SVPWM) strategy. From the results, it can be concluded that the optimized DDPWM technique gives the best performance. This technique has reduced the CMV by one level and reduces the losses by 50% while having the same THD and ZSV obtained with the SVPWM technique.Peer reviewe

Design and Control of Power Converters 2019

In this book, 20 papers focused on different fields of power electronics are gathered. Approximately half of the papers are focused on different control issues and techniques, ranging from the computer-aided design of digital compensators to more specific approaches such as fuzzy or sliding control techniques. The rest of the papers are focused on the design of novel topologies. The fields in which these controls and topologies are applied are varied: MMCs, photovoltaic systems, supercapacitors and traction systems, LEDs, wireless power transfer, etc

Modulation and Control Techniques for Performance Improvement of Micro Grid Tie Inverters

The concept of microgrids is a new building block of smart grid that acts as a single controllable entity which allows reliable interconnection of distributed energy resources and loads and provides alternative way of their integration into power system. Due to its specifics, microgrids require different control strategies and dynamics of regulation as compared to ones used in conventional utility grids. All types of power converters used in microgrid share commonalities which potentially affect high frequency modes of microgrid in same manner. There are numerous unique design requirements imposed on microgrid tie inverters, which are dictated by the nature of the microgrid system and bring major challenges that are reviewed and further analyzed in this work. This work introduces, performs a detailed study on, and implements nonconventional control and modulation techniques leading to performance improvement of microgrid tie inverters in respect to aforementioned challenges

Controle coordenado em microrredes de baixa tensão baseado no algoritmo power-based control e conversor utility interface

Orientadores: José Antenor Pomilio, Fernando Pinhabel MarafãoTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de ComputaçãoResumo: Esta tese apresenta uma possível arquitetura e sua respectiva estratégia de controle para microrredes de baixa tensão, considerando-se a existência de geradores distribuídos pela rede. A técnica explora totalmente a capacidade dos geradores distribuídos em ambos os modos de operação: conectado à rede e ilhado. Quando conectado à rede, sob o modo de otimização global, o controle busca a operação quase ótima da microrrede, reduzindo as perdas de distribuição e os desvios de tensão. Quando em modo ilhado, a técnica regula de forma eficaz os geradores distribuídos disponíveis, garantindo a operação autônoma, segura e suave da microrrede. A estratégia de controle é aplicada a uma estrutura de microrrede completamente despachável, baseada em uma arquitetura de controle mestre-escravo, em que as unidades distribuídas são coordenadas por meio do recém-desenvolvido algoritmo Power-Based Control. As principais vantagens da arquitetura proposta são a expansividade e a capacidade de operar sem sincronização ou sem conhecimento das impedâncias de linha. Além disso, a microrrede regula as interações com a rede por meio do conversor chamado de Utility Interface, o qual é um inversor trifásico com armazenador de energia. Esta estrutura de microrrede permite algumas vantagens como: compensação de desbalanço e reativo, rápida resposta aos transitórios de carga e de rede, e suave transição entre os modos de operação. Em contrapartida, para compartilhar a potência ativa e reativa proporcionalmente entre as unidades distribuídas, controlar a circulação de reativos, e maximizar a operação, a comunicação da microrrede requer em um canal de comunicação confiável, ainda que sem grandes exigências em termos de resolução ou velocidade de transmissão. Neste sentido, foi demonstrado que uma falha na comunicação não colapsa o sistema, apenas prejudica o modo de otimização global. Entretanto, o sistema continua a operar corretamente sob o modo de otimização local, que é baseado em um algoritmo de programação linear que visa otimizar a compensação de reativos, harmônicos e desbalanço de cargas por meio dos gerador distribuído, particularmente, quando sua capacidade de potência é limitada. Esta formulação consiste em atingir melhores índices de qualidade de energia, definidos pelo lado da rede e dentro de uma região factível em termos de capacidade do conversor. Baseado nas medições de tensão e corrente de carga e uma determinada função objetiva, o algoritmo rastreia as correntes da rede ótima, as quais são utilizadas para calcular os coeficientes escalares e finalmente estes são aplicados para encontrar as referências da corrente de compensação. Finalmente, ainda é proposta uma técnica eficiente para controlar os conversores monofásicos conectados arbitrariamente ao sistema de distribuição trifásico, sejam conectados entre fase e neutro ou entre fase e fase, com o objetivo de compensar o desbalanço de carga e controlar o fluxo de potência entre as diferentes fases da microrrede. Isto melhora a qualidade da energia elétrica no ponto de acoplamento comum, melhora o perfil de tensão nas linhas, e reduz as perdas de distribuição. A arquitetura da microrrede e a estratégia de controle foi analisada e validada através de simulações computacionais e resultados experimentais, sob condições de tensão senoidal/simétrica e não-senoidal/assimétrica, avaliando-se o comportamento em regime permanente e dinâmico do sistema. O algoritmo de programação linear que visa otimizar a compensação foi analisado por meio de resultados de simulaçãoAbstract: This thesis presents a flexible and robust architecture and corresponding control strategy for modern low voltage microgrids with distributed energy resources. The strategy fully exploits the potential of distributed energy resources, under grid-connected and islanded operating modes. In grid-connected mode, under global optimization mode, the control strategy pursues quasi-optimum operation of the microgrid, so as to reduce distribution loss and voltage deviations. In islanded mode, it effectively manages any available energy source to ensure a safe and smooth autonomous operation of the microgrid. Such strategy is applied to a fully-dispatchable microgrid structure, based on a master-slave control architecture, in which the distributed units are coordinated by means of the recently developed power-based control. The main advantages of the proposed architecture are the scalability (plug-and-play) and capability to run the distributed units without synchronization or knowledge of line impedances. Moreover, the proposed microgrid topology manages promptly the interaction with the mains by means of a utility interface, which is a grid-interactive inverter equipped with energy storage. This allows a number of advantages, including compensation of load unbalance, reduction of harmonic injection, fast reaction to load and line transients, and smooth transition between operating mode. On the other hand, in order to provide demand response, proportional power sharing, reactive power control, and full utilization of distributed energy resources, the microgrid employs a reliable communication link with limited bit rate that does not involve time-critical communications among distributed units. It has been shown that a communication failure does not jeopardize the system, and just impairs the global optimization mode. However, the system keeps properly operating under the local optimization mode, which is managed by a linear algorithm in order to optimize the compensation of reactive power, harmonic distortion and load unbalance by means of distributed electronic power processors, for example, active power filters and other grid-connected inverters, especially when their capability is limited. It consists in attain several power quality performance indexes, defined at the grid side and within a feasible power region in terms of the power converter capability. Based on measured load quantities and a certain objective function, the algorithm tracks the expected optimal source currents, which are thereupon used to calculate some scaling coefficients and, therefore, the optimal compensation current references. Finally, the thesis also proposes an efficient technique to control single-phase converters, arbitrarily connected to a three-phase distribution system (line-to-neutral or line-to-line), aiming for reduce unbalance load and control the power flow among different phases. It enhances the power quality at the point-of-common-coupling of the microgrid, improve voltage profile through the lines, and reduce the overall distribution loss. The master-slave microgrid architecture has been analyzed and validated by means of computer simulations and experimental results under sinusoidal/symmetrical and nonsinusoidal/asymmetrical voltage conditions, considering both the steady-state and dynamic performances. The local optimization mode, i.e., linear algorithm for optimized compensation, has been analyzed by simulation resultsDoutoradoEnergia EletricaDoutor em Engenharia Elétrica2012/24309-8, 2013/21922-3FAPES

デュアルインバータ駆動オープン巻線誘導電動機の位相制御変調を用いた低負荷領域における高調波低減に関する研究

国立大学法人長岡技術科学大

Power Electronics Applications in Renewable Energy Systems

The renewable generation system is currently experiencing rapid growth in various power grids. The stability and dynamic response issues of power grids are receiving attention due to the increase in power electronics-based renewable energy. The main focus of this Special Issue is to provide solutions for power system planning and operation. Power electronics-based devices can offer new ancillary services to several industrial sectors. In order to fully include the capability of power conversion systems in the network integration of renewable generators, several studies should be carried out, including detailed studies of switching circuits, and comprehensive operating strategies for numerous devices, consisting of large-scale renewable generation clusters

Advances in Control of Power Electronic Converters

This book proposes a list of contributions in the field of control of power electronics converters for different topologies: DC-DC, DC-AC and AC-DC. It particularly focuses on the use of different advanced control techniques with the aim of improving the performances, flexibility and efficiency in the context of several operation conditions. Sliding mode control, fuzzy logic based control, dead time compensation and optimal linear control are among the techniques developed in the special issue. Simulation and experimental results are provided by the authors to validate the proposed control strategies

Advanced Converter Control Techniques for Improving the Performances of DFIG based Wind Turbines

Unter den alternativen erneuerbaren Energiequellen hat Windenergie in den letzten zehn Jahren den größten Stellenwert im Energieerzeugungssystem erlangt. Die Erhaltung bzw. die Verbesserung der Zuverlässigkeit des Stromversorgungsnetzes mit zunehmenden Windenergieanlagen und deren optimale Nutzung ist eine der wichtigsten Aufgaben. Die Windenergieanlagen sind im Netzbetrieb bestimmten in Netzanschlussrichtlinien angegebenen Anschlussregeln unterworfen. Dies erfordert eine detaillierte Untersuchung von Windenergieanlagen in verschiedenen operativen Szenarien, so dass geeignete Lösungen empfohlen werden können, insbesondere bezüglich Umrichter-Regelung, die die Hauptrolle im Gesamtsystem spielen. In dieser Forschung wurde der doppelt-gespeiste Asynchrongenerator, der immer noch am häufigsten verwendeter Windturbinentyp ist, für eine detaillierte Untersuchung ausgewählt. Sowohl das Betriebsverhalten im stationären Betrieb allgemein als auch unter Berücksichtigung von zwei alternativen Pulsweiten-Modulation (PWM)-Typen und verschiedenen Umrichter-Topologie, untersucht. Vergleichskriterien sind die erzeugte maschinenseitige „common mode“ Spannung, Gesamtverzerrung der Stromwelle im Niederspannungsnetz, Umrichter-Leistungsverluste und Blindleistung-Einspeisefähigkeit. Zusätzlich werden die Anzahl der Komponenten im kompletten Umrichter-System und die geschätzten Kosten als Vergleichskriterien herangezogen. Bezüglich des ersten Szenarios, der Einfluss unterschiedlicher PWM-Typen auf Umrichter Verlustleistung, die Blindleistung-Einspeisefähigkeit und die gesamte harmonische Verzerrung wurden im Detail untersucht, und der am besten geeignete PWM-Typ bezüglich optimaler Leistungskriterien sowie Drehzahlbereiche vorgeschlagen. Im zweiten Szenario wurden zwei verschiedene Umrichter-Topologie, nämlich zweistufiger „Back-to-Back“ Umrichter und dreistufiger „Neutral-Point-Clamped (NPC)“ „Back-to-Back“ Umrichter wurden im Simulationsmodell implementiert, und auf der Grundlage der Simulation Ergebnisse ihre Eignung in Bezug auf Kosten gegen die anfallenden Betriebsvorteile verglichen. Schließlich wurde ein neues Schutzschema für „Fault-Ride-Through“ im dreistufigen „Backto- Back“ NPC-Umrichter als Alternative zum konventionellen Schutzschema mit Chopper im Gleichspannung-Zwischenkreis vorgeschlagen. Das vorgeschlagene Schema zeigt ein sehr ähnliches dynamisches Verhalten wie das konventionelle Schema, wenn die inneren IGBTs des maschinenseitigen Wechselrichters (MWR) für etwa zweifachen Nennstrom der Überstromschutzgrenze ausgelegt werden. Außerdem ermöglicht eine einfachere Bedienung ohne höhere Anzahl von Komponenten. Die Verwendung von inneren IGBTs mit höherem Nennstrom erhöht die Kosten der MWR. Jedoch werden die Gesamt Kosten um etwa 15% weniger, da der Chopper im Gleichspannung-Zwischenkreis dadurch überflüssig gemacht wird.Among the renewable energy alternatives, wind energy has made the biggest impact on the total energy production in the last decade. Maintaining or improving the reliability of the wind turbine system in power generation sector with optimal performances is one of the important tasks. Especially the wind turbines connected to the grid are subjected to certain electricity grid connection regulations specified in grid codes. A detailed study of the performance of wind turbine systems in various case scenarios is necessary, so that appropriate solutions can be recommended, especially in the converter controls which play the major role in the overall system. In this thesis, the doubly fed induction generator (DFIG) which is still the most widely used wind turbine type is selected for detailed investigation. Its performances during steady state operation in two alternative scenarios, namely, using different pulse width modulation (PWM) types and using different converter topologies, are investigated. The performance criteria include generated common mode voltage at machine side converter (MSC), current total harmonic distortion in the low voltage network, converter power losses and reactive power capability. Additionally, the component counts in the converter and its estimate cost are compared. Regarding the first scenario, the influence of different PWM types on the converter power losses, the reactive power capability and the total harmonic distortion has been investigated in detail, and the most suitable PWM type depending on the optimal performance criteria as well as operational speed range is proposed. In the second scenario, two different converter topologies, namely back-to-back two-level converter and back-to-back three-level neutral point clamped (NPC) converter were implemented in the simulation model, and on the basis of the simulation results their performances in terms of cost against the accruing operational advantages are compared. Finally, a new protection scheme for fault ride-through in back-to-back three-level NPC converter is proposed as an alternative to conventional protection scheme using DC-link chopper. The proposed scheme shows a very similar dynamic behaviors with the conventional scheme when the inner IGBTs of the MSC are designed for about two times higher current rating than the over-current protection limit. Furthermore, it implements simpler operation without higher component count. The need for the inner IGBTs with higher current rating significantly increases the cost of the MSC. However, the total cost of the DFIG system is slightly reduced about 15% by the elimination of the DC-link chopper circuit

Power Converters in Power Electronics

In recent years, power converters have played an important role in power electronics technology for different applications, such as renewable energy systems, electric vehicles, pulsed power generation, and biomedical sciences. Power converters, in the realm of power electronics, are becoming essential for generating electrical power energy in various ways. This Special Issue focuses on the development of novel power converter topologies in power electronics. The topics of interest include, but are not limited to: Z-source converters; multilevel power converter topologies; switched-capacitor-based power converters; power converters for battery management systems; power converters in wireless power transfer techniques; the reliability of power conversion systems; and modulation techniques for advanced power converters