Study on Parallel Operation for Distributed Generation Inverter based on Droop control Kim Hyun-jun Department of Electrical Engineering Graduate School, Myongji University

Study on Parallel Operation for Distributed Generation Inverter based on Droop control Kim Hyun-jun Department of Electrical Engineering Graduate School, Myongji University Directed by Professor Han Byung-moon

 When the droop control is conducted through the inverter for distributed generation, active/reactive power coupling occurs because of the resistive component of the output impedance. In case of long distance distribution line, the voltage drop caused by the line impedance between the PCC and output voltage changes initially designed property curves of the Q-V droop. So, the control performance of Q-V droop is deteriorated and it causes an error of reactive power control and distribution. Therefore, a new droop control, which is to improve the power coupling and the accuracy of reactive power, is proposed in this paper. Its effectiveness is proved by the performance evaluation that relates to unbalanced power compensation, which should be prepared by the inverter for distributed power, random switch and system reconnection that are required when the drive mode is converted. In general, the droop control is used for the high voltage system, so that resistive component of line impedance is ignored because of significant inductive However, the line impedance has more significance in resistive component than inductive component in the low power distribution system, so that the power coupling occurs. To solve this problem, many of the improved droop control method have been proposed in various ways. Most typical method is the virtual impedance type. The virtual impedance type readjusts the output impedance to have inductivity, even though there is a significant resistive component caused by the output impedance of the inverter and low voltage line impedance. Therefore, it is effective to remove the power coupling that is generated by the resistive component. However, increased virtual impedance can also increase reactive power control or distribution error. In addition, though the virtual impedance type prevents power coupling, the reactive power control or distribution error caused by the line impedance can not be compensated. Therefore, there should be an additional control method to improve the reactive method and distribution accuracy influenced by the line impedance. There are two types of general methods; One is Q-VPCC droop control type, which directly measure the PCC voltage using the communication and conduct droop control. The other is indirect Q-V voltage droop control type that estimates the drop control of line impedance and compensated it. In the Q-VPCC droop control type, each inverter is controlled by identical PCC voltage, so that it is not influenced by the line impedance and enables accurate reactive power control and distribution. However, additional voltage sensor to measure PCC voltage should be installed, and inverters for distributed power are located far away from the PCC, thereby requiring communication line to deliver the information of PCC voltage. Therefore, indirect voltage droop control method has been proposed to make up for the defect of direct voltage type. The approximated value of the voltage drop component caused by the line impedance is calculated by active/reactive power, so that the PCC voltage can be estimated and it enables accurate reactive power control and distribution. However, most indirect voltage types use approximated value of voltage drop caused by active/reactive power, so that it is only effective for small line impedance. Since the large value of line impedance can lead to significant error of approximated voltage drop value, reactive power control and distributed error cannot be completely improved. It also requires the information of the line impedance. Therefore, a new droop control, which is to solve defects of the power coupling, reactive power control, and distribution is proposed in this paper. The proposed method conducts the droop control using the dq transformation. Since the droop control is conducted on the dq coordinate, the Q-V droop voltage control method becomes similar to the DC droop control and the power coupling is removed. Therefore, output impedance component in the normal condition, since the DC voltage value is controlled. In other words, the power decoupling is enabled without adding virtual impedance to the droop controller. In addition, errors of reactive power control and distribution that occurs because of the error of voltage drop in the line impedance can be compensated by calculating accurate voltage drop value on the dq coordinate. Using the proposed droop control method, unbalanced load compensation, random switch performance, and system reconnection issues were handled that were also fundamental performance index for the inverter of distributed power. Finally, the PSCAD/EMTDC simulation and two of 5 kw prototype inverters for distributed power were produced and utilized in the experiment of theoretical verification.

 Keyword Droop Control, Seamless Transfer, Inverter-based distributed generator(DG), Reconnection, Energy Storage System, Reactive power sharing compensation Unbalanced Voltage compensation

Seminário Mecanismos de Qualidade no Setor Fotovoltaico 10/08/2018 - Tarde

Seminário Mecanismos de Qualidade no Setor Fotovoltaico 10/08/2018 - Manhã

Transmissão de energia elétrica em corrente contínua - Prof. Dr. Kleber -Departamento de engenharia elétrica da UNIVERSIDADE FEDERAL DE CEARA-BRASIL

VAE 9 - Microprocessadores - PIC16F628A MPLAB IDE

A Lacerda Sistemas de Energia marcou presença no Seminário Mecanismos de Qualidade no Setor Fotovoltaico-Instituto de Energia e Ambiente da Universidade de São Paulo-IEE-USP-SÃO PAULO

 Esquerda/ Direita: Eng.Armando Cavero Miranda(Lacerda Sistemas de energia) Shaw O'Brien (NABCEP, Certificadora nos EUA de Sistemas Fotovoltaicos).
Hoje se realizou com sucesso o Seminário Mecanismos de Qualidade no Setor Fotovoltaico,com aassistencia de representantes da Pesquisa Académica das Universidades,Empresas de energia,Engenheiros Eletricos e Eletronicos,Convidados internacionais.

O Serviço Técnico de Sistemas Fotovoltaicos do Instituto de Energia e Ambiente da Universidade de São Paulo, em conjunto com ABENS (Associação Brasileira de Energia Solar); ABINEE (Associação Brasileira da Indústria Elétrica e Eletrônica); ABGD (Associação Brasileira de Geração Distribuída); ABSOLAR (Associação Brasileira de Energia Solar Fotovoltaica); SENAI (Serviço NAcional de Aprendizagem Industrial) e GIZ (Agência de Cooperação Alemã) organizarom o evento.
O Seminário discutiu questões estruturais que contribuem para promover a qualidade nas instalações fotovoltaicas. Ele será baseado no conceito Quality Infrastructure da Agência Internacional de Energias Renováveis (IRENA) que envolve três mecanismos, que são:
 a) Normas e Regulamentação;
b) Certificação de Produtos;
 c) Certificação de Pessoas

 Os palestrantes convidados são renomados atores chave do Setor Fotovoltaico incluindo a participação internacional do diretor da certificadora americana NABCEP, Shawn O'Brien.

Seminário Mecanismos de Qualidade no Setor Fotovoltaico-10 agosto de 2018 9h00 às 17h00 Auditório do IEE/USP - Av. Prof. Luciano Gualberto, 1.289 - Cidade Universitária, São Paulo-BRASIL

Seminário Mecanismos de Qualidade no Setor Fotovoltaico Data: sexta-feira, 10 Agosto, 2018 - 09:00 até 17:00
O Serviço Técnico de Sistemas Fotovoltaicos do Instituto de Energia e Ambiente da Universidade de São Paulo, em conjunto com ABENS (Associação Brasileira de Energia Solar); ABINEE (Associação Brasileira da Indústria Elétrica e Eletrônica); ABGD (Associação Brasileira de Geração Distribuída); ABSOLAR (Associação Brasileira de Energia Solar Fotovoltaica); SENAI (Serviço NAcional de Aprendizagem Industrial) e GIZ (Agência de Cooperação Alemã) convidam para o Seminário MECANISMOS DE QUALIDADE NO SETOR FOTOVOLTAICO 10 agosto de 2018 9h00 às 17h00 Auditório do IEE/USP - Av. Prof. Luciano Gualberto, 1.289 - Cidade Universitária, São Paulo

INSCRIÇÕES ENCERRADAS Haverá transmissão via Youtube, pelo canal IEE/USP Oficial
https://www.youtube.com/channel/UCzwv5TA7-ASIpXExAx-aazg 

 O Seminário pretende discutir questões estruturais que contribuem para promover a qualidade nas instalações fotovoltaicas. Ele será baseado no conceito Quality Infrastructure da Agência Internacional de Energias Renováveis (IRENA) que envolve três mecanismos, que são: a) Normas e Regulamentação; b) Certificação de Produtos; c) Certificação de Pessoas Os palestrantes convidados são renomados atores chave do Setor Fotovoltaico incluindo a participação internacional do diretor da certificadora americana NABCEP, Shawn O'Brien. O público alvo do evento é composto por stakeholders e agentes do setor fotovoltaico como concessionárias, seguradoras, instituições financeiras, instituições de ensino, integradoras e fabricantes. PROGRAMAÇÃO 09h00 - Abertura dos Trabalhos Representantes das instituições organizadora do evento (IEE/USP, ABINEE, ABSOLAR, ABGD, ABENS, SENAI/SSCP e GIZ Mecanismos de Qualidade no Setor Fotovoltaico 09h30 - Apresentação do conceito IRENA - Infraestrutura/Mecanismos de Qualidade no Setor Fotovoltaico Roberto Zilles, IEE/USP Normas e Regulamentação 10h00 - ABNT CB-03/IEC 60364-7: Instalações elétricas de baixa tensão: Arranjos Fotovoltaicos Marcelo Pinho, IEE/USP 10h30 - Experiências das Distribuidoras com Geração Distribuída/Sistemas de Compensação Ciceli Martins Luiz, CEMIG 11h00 - Visão das Distribuidoras sobre Geração Distribuída/Sistemas de Compensação Elio Vicentini, ABRADEE 11h30 - Roda de perguntas e discussão em plenário 12h00 - Intervalo de almoço Certificação de Produtos 14h00 - Critérios de Qualidade em Módulos Fotovoltaicos Marcelo Sousa, Jinko Solar 14h20 - Critérios de Qualidade em Cabos Fotovoltaicos Thiago Ferreira, Prysmian 14h40 - Critérios de Qualidade em Dispositivos de Proteção contra Surto (DPS) para Sistemas Fotovoltaicos Bruno Sacute, Finder 15h00 - Roda de perguntas e discussão em plenário Certificação de Pessoas 15h30 - Experiências Internacionais com Certificação de Instaladores de Sistemas Fotovoltaicos Shaw O'Brien, NABCEP, Certificadora nos EUA 16h00 - Certificação de Instaladores de Sistemas Fotovoltaicos SENAI/SSCP no Brasil Fernando Gusmão, SENAI/SSCP 16h30 - Roda de perguntas e discussão em plenário 17h00 - Encerramento

Solar Power System Modeling and Performance Analysis Jiaqi Wang Faculty of Engineering and Computer Science University of Denver

Solar Power System Modeling and Performance Analysis Jiaqi Wang Faculty of Engineering and Computer Science University of Denver Author: Jiaqi Wang Title: Solar Power System Modeling and Performance Analysis Advisors: WenZhong Gao Degree Date: August 2011 Abstract At present the main source of our power and energy needs are from fossil fuel; almost all transportation tools and nearly 70% of electrical power are produced by fossil fuel. But unfortunately these materials are limited in our planet, with obvious drawback such as pollution. So looking for new kinds of energy supply is an urgent matter. Solar-powered photovoltaic system provides a clean energy solution to this problem. It is developing fast all over the world in terms of both research work and actual applications. It is estimated that the power supplied by solar energy can provide 10 percent of United States power needs. This thesis mainly discusses photovoltaic system modeling from the beginning of site selection to system sizing. Some tools are used during the project. A GIS application is used to help developers in the preliminary studies. Photovoltaic system simulation software PVsyst involves the system components setting and sizing process. Two types of systems are built in this study: stand-alone system and grid connected system; the location is set at Denver, Colorado. For each system the array mounting, analysis of loads and modules selection are studied. The simulation is performed after the system model is completed, the results includes loss diagrams, system energy yields and system efficiencies. At last the economic analysis and comparison between the two types of PV systems is analyzed.

 LINK
https://digitalcommons.du.edu/cgi/viewcontent.cgi?article=1688&context=etd

Performance of a Single-Stage UPS System for Single-Phase Trapezoidal-Shaped AC-Voltage Supplies Praveen K. Jain, Senior Member, IEEE, Jos´e R. Espinoza, Student Member, IEEE, and Hua Jin, Member, IEEE

Performance of a Single-Stage UPS System for Single-Phase Trapezoidal-Shaped AC-Voltage Supplies Praveen K. Jain, Senior Member, IEEE, Jos´e R. Espinoza, Student Member, IEEE, and Hua Jin, Member, IEEE

 Abstract— A high-performance single-stage UPS system for single-phase ac power supply systems is presented. The topology generates a trapezoidal-shaped load voltage that is synchronized with the ac supply, therefore, a small dc-link capacitor is required. This feature leads to a high-input power factor (0.94 at nominal voltage), and due to the single-stage structure, high efficiency (93% at nominal voltage) is also achieved. Moreover, in both cases the supply current spectrum presents low-order harmonics, all of which satisfy IEC 555. The high performance is validated using both resistive (linear) and diode RC (nonlinear) loads. The dynamic performance of the UPS system is also analyzed under different transient conditions. Specifically, the supply to battery, battery to supply transition, load transient, and supply/battery-voltage transients are performed. They show a transfer time of 500 s (from ac supply to battery) and overvoltages of at most 15%. The dynamic and static evaluations are performed on a 1-kVA UPS system. The design guidelines for the key components and control parameters are also included.
Index Terms— AC mains synchronization, PWM inverter, single-phase single-stage conversion topology, trapezoidal-shaped ac output voltage, UPS.

LINK ORIGINAL
http://www.lcda.cl/descargas/Jain_Espinoza_Jin_.pdf

Simulation and Implementation of Γ-Z Source Inverter G.V.Sreekanth Reddy*, J.N.Chandrasekhar** *(M.Tech, Department of EEE, Sri Venkateswara university College of Engineering, Tirupati ** (Assistant Professor, Department of EEE,Sri Venkateswara university College of Engineering, Tirupati

Simulation and Implementation of Γ-Z Source Inverter

 G.V.Sreekanth Reddy*, J.N.Chandrasekhar** *(M.Tech, Department of EEE, Sri Venkateswara university College of Engineering, Tirupati ** (Assistant Professor, Department of EEE,Sri Venkateswara university College of Engineering, Tirupati

ABSTRACT
This venture "Simulation and Implementation of Γ-Z-Source Inverters" is made out of Voltage-sort Γ-Z source inverters are proposed in this letter. They utilize a remarkable Γ-molded impedance arrange for boosting their yield voltage notwithstanding their standard voltage buck conduct. Contrasting them and different topologies, the proposed inverters utilize lesser parts and a coupled transformer for delivering the high-pick up and regulation proportion all the while. The got pick up can be tuned by changing the turns proportion γΓZ of the transformer inside the limited scope of 1 < γΓZ ≤ 2. This prompts to lesser twisting turns at high pick up, as compared to other related topologies.

 Keywords - Embedded-Z-source, quasi-Z-source, T-source, Trans-Z-source, Z-source, Γ-Z-source inverters.

LINK
http://www.ijera.com/papers/Vol7_issue1/Part-5/A0701050105.pdf

Line-Interactive Transformerless Uninterruptible Power Supply (UPS) with a Fuel Cell as the Primary Source Muhammad Iftikhar , Muhammad Aamir, Asad Waqar , Naila, Fahad Bin Muslim and Imtiaz Alam Department of Electrical Engineering, University of Engineering and Technology,Peshawar, Pakistan

Line-Interactive Transformerless Uninterruptible Power Supply (UPS) with a Fuel Cell as the Primary Source 
 Muhammad Iftikhar , Muhammad Aamir, Asad Waqar , Naila, Fahad Bin Muslim and Imtiaz Alam Department of Electrical Engineering, University of Engineering and Technology,Peshawar, Pakistan

 Abstract: This paper presents line-interactive transformerless Uninterruptible Power Supply (UPS) with a fuel cell as the prime energy source. The proposed UPS consists of three major parts (i.e., an output inverter, a unidirectional DC–DC converter, and a battery charger/discharger). Non-isolated topologies of both the unidirectional converter and battery charger/discharger ensure transformerless operation of the UPS system. A new topology of high gain converter is employed for boosting the low voltage of the fuel cell to a higher DC link voltage, with minimum semiconductor count, and high efficiency. A high-gain battery charger/discharger realizes the bidirectional operation between the DC link and the battery bank. Besides, it regulates the DC link voltage during the cold start of fuel cells and keeps the battery bank voltage to only 24 V. A new inverter control scheme is introduced that regulates the output voltage and minimizes the total harmonic distortion for non-linear loading condition. The proposed control scheme integrates proportional-resonant control with slide mode control, which improves the controller’s performance in transient conditions. The proposed UPS system is validated by developing a 1-kVA experimental prototype.

 Keywords: fuel cell; line-interactive; uninterruptible power supply; transformerless; DC–DC ORIGINAL LINK
https://www.mdpi.com/1996-1073/11/3/542/pdf

INPUT STAGE WITH DOUBLE FUNCTIONALITY APPLIED TO A HIGH PERFORMANCE THREE-PHASE UPS-William A. Venturini, Henrique Jank, Fábio E. Bisogno, Mário L. S. Martins, Humberto Pinheiro Universidade Federal de Santa Maria, Santa Maria – RS-BRASIL

ESTÁGIO DE ENTRADA COM DUPLA FUNCIONALIDADE APLICADO A UMA UPS TRIFÁSICA DE ALTO DESEMPENHO
 William A. Venturini, Henrique Jank, Fábio E. Bisogno, Mário L. S. Martins, Humberto Pinheiro Universidade Federal de Santa Maria, Santa Maria – RS, Brasil

 Resumo – Este trabalho apresenta uma configuração topológica que permite utilizar o estágio de entrada de uma UPS de dupla conversão como retificador trifásico, em modo normal de operação, e como conversor CC/CC elevador de tensão, em modo bateria. Dessa forma, evita-se o uso de um circuito específico para a descarga do banco de baterias, o qual deve ser dimensionado para a potência nominal da UPS. É apresentada a análise de funcionamento do estágio de entrada proposto, bem como a modelagem matemática e o sistema de controle que garantem a aplicabilidade na correção do fator de potência de entrada, no controle da tensão de barramento e ainda no equilíbrio das tensões sobre os capacitores de barramento. A metodologia desenvolvida e a boa performance do sistema proposto são validados através de resultados obtidos em uma plataforma hardware-in-theloop, modelo Typhoon HIL402. Os resultados são adquiridos para uma UPS trifásica de 20 kVA.

Abstract – This work presents a topological configuration that allows the input stage of a double conversion UPS to be used as a three-phase rectifier and a DC/DC voltage boost converter in normal and backup operating mode, respectively. Thus, the use of a specific circuit for the discharge of the battery bank, which would be rated for UPS nominal power, is avoided. The operation analysis of the proposed input stage is presented, as well as the mathematical modeling and the control system that guarantee the applicability in the input power factor correction, DC bus voltage control and for the DC bus capacitors voltage balance. Hardware-in-the-loop results are acquired for a 20 kVA three-phase UPS to validate the developed analysis besides to demonstrate the good performance of the system.

VII. CONCLUSÕES
 Este trabalho apresentou uma configuração topológica de estágio de entrada com dupla funcionalidade aplicado a uma UPS de alto desempenho. A característica de dupla funcionalidade é evidenciada pelo uso do mesmo circuito para condicionar a energia demandada pela carga, tanto em modo normal, quanto em modo bateria de operação, operando como um retificador trifásico e como um conversor CC/CC elevador de tensão para a descarga do banco de baterias, respectivamente. Esta característica não é observada na literatura, sendo usualmente utilizado um conversor específico para a descarga do banco de baterias, o qual deve ser dimensionado para a potência nominal da UPS. É apresentada a modelagem de pequenos sinais e o projeto dos controladores que garantem a funcionalidade do estágio de entrada proposto. A metodologia de projeto e o desempenho da topologia em questão são validados a partir de resultados obtidos através de uma plataforma
hardware-in-the-loop de alta fidelidade para uma UPS de 20 kVA.

AGRADECIMENTOS Os autores gostariam de agradecer ao CNPq, CAPES e grupo LEGRAND pelo suporte financeiro a esta pesquisa.

  Palavras-Chave – Correção do Fator de Potência, Fonte Ininterrupta de Energia, Retificador Trifásico.
LINK FULL PAPER
https://www.sobraep.org.br/site/uploads/2018/06/rvol23no2p21.pdf

Optimal Design of Switching Power Supply Por Zhanyou Sha, Xiaojun Wang, Yanpeng Wang, Hongtao Ma

BOOK DEMO GOOGLE

Pulsed Plasma Thrusters for Small Satellites -Peter Vallis Shaw - Surrey Space Centre Faculty of Engineering & Physical Sciences University of Surrey -United Kingdom.

Pulsed Plasma Thrusters for Small Satellites Peter Vallis Shaw
 Submitted for the Degree of Doctor of Philosophy from the University of Surrey Surrey Space Centre Faculty of Engineering & Physical Sciences University of Surrey -United Kingdom.

 Abstract
 Since the Russian launch of the Zond-2 satellite in 1964 there have been over fifty years of research dedicated to the understanding of the first electric propulsion device to be flown in space, the Pulsed Plasma Thruster. The Pulsed Plasma Thruster originates from the evolution of the vacuum arc switch, but due to its microsecond operation time, the internal dynamics and nature of operation have remained unclear. The Pulsed Plasma Thruster is generally cheap to manufacture and to operate, which keeps it a popular device to research within institutes worldwide and has contributed to its longevity. As a satellite propulsion device it has unique capabilities that other propulsion systems cannot provide. The thruster operates by accelerating plasma formed in the accelerating electrodes (or nozzle) in short discrete packets of thrust or impulse. The pulsed nature of the thruster means that between pulses energy can be stored in capacitors, ready for the next discharge. The storage of energy over time means the power draw is variable and is only dependant on the frequency that the system is pulsed at. This property of the thruster makes the Pulsed Plasma Thruster extremely versatile, allowing the thruster to perform both velocity correction and control manoeuvres and attitude control manoeuvres. The Pulsed Plasma Thruster is mechanically scalable but the performance of the thruster has been shown to depend linearly on the energy storage ability of the thruster’s capacitor. The work presented here covers two areas. Firstly is the critical analysis of the physical mechanisms that occur within a Pulsed Plasma Thruster through a review of literature, experimentation and the development of a high current plasma flow model. The second area is the design, development, manufacture and evaluation of the Pulsed Plasma Thruster for use on a nanosatellite platform known as the CubeSat. Several novel observations and contributions were made during the critical analysis of the physical mechanisms of the Pulsed Plasma Thruster. The most significant was realising how the erosion of the metal electrodes affected the overall discharge process. It is postulated that the expulsion of material from emission sites (or cathode spots), the ionisation of that material and the resulting freed electrons, create a pinched plasma column between the electrodes. It is postulated that the interaction of the electrode sheath region and the intersecting plasma column cause the current flow to become limited. This was then shown to affect the efficiency with which the stored energy of the capacitor was converted to energy to accelerate the plasma. Understanding this issue is key in improving future designs of the Pulsed Plasma Thruster. The observations and conclusions made during this work were put into practice to create an eight µPPT propulsion module for a 3U CubeSat. Initial results show that a µPPT with a specific impulse of 321s, an impulse bit of 0.56µNs and a mass bit of 0.17µg has been developed. The thruster was developed for two technology demonstration CubeSats. STRaND-1 is a joint collaboration between Surrey Space Centre and Surrey Satellite Technology Limited and UKUBE-1 is a joint collaboration between Surrey Space Centre and the UK Space Agency. Both CubeSats are scheduled for launch late 2011, early 2012. The propulsion module for the STRaND-1 CubeSat will be the first to provide full axis control and the first to provide electric propulsion on this class of satellite, showing the advantages of the Pulsed Plasma Thruster for Small Satellites.
LINK THESIS
http://epubs.surrey.ac.uk/745999/1/Thesis_P_Shaw.pdf

Analog Electronic Circuits-Prof. Jeong, Deog-Kyoon-Electrical and Computer Engineering-SEOUL NATIONAL UNIVERSITY

LINK
http://ocw.snu.ac.kr/node/27126