Switching Loss Reduction of AC-AC Converter using Three-level Rectifier and Inverter for UPS. Kazuki Yoneda, Hiroki Takahashi and Jun-ichi Itoh Dept. of Electrical, Electronics and Information Engineering Nagaoka University of Technology Nagaoka, Niigata, Japan

Abstract— This paper proposes an AC-AC converter, which consists of T-type three-level rectifier and inverter, for an on-line UPS. The switching loss of the proposed AC-AC converter is drastically reduced because the proposed converter is driven at a very low switching frequency which is six times of input side frequency. The T-type rectifier separates the maximum phasevoltage, medium phase-voltage and minimum phase-voltage from the input voltage. Next the output waveform is built by the T-type inverter from each maximum phase-voltage, middle phasevoltage and minimum phase-voltage. The proposed circuit can achieve not only high efficiency, but also short instantaneous interruption time. Furthermore, the proposed AC-AC converter compensates a voltage dip with changing an operation mode of a rectifier. In this paper, the fundamental operation of the proposed converter is confirmed by simulations and experiments. In addition, the power loss of the proposed converter is compared to a conventional on-line UPS and the efficiency of the proposed converter is 97.1% at rated load in an experiment.

FULL PAPER  LINK ORIGINAL NA WEB
http://itohserver01.nagaokaut.ac.jp/itohlab/paper/2014/141105_peac2014/yoneda.pdf
LINK ALTERNATIVO
https://copy.com/LkWFpaxB26DaKPAI

A Novel Single-Phase Cascaded Multilevel AC-AC Converter Without Commutation Problem Kim, Sang-hun Department of Electrical Engineering Graduate School, Kyungpook National University Daegu, Korea

ABSTRACT
A Novel Single-Phase Cascaded Multilevel AC-AC Converter Without Commutation Problem Kim, Sang-hun Department of Electrical Engineering Graduate School, Kyungpook National University Daegu, Korea (Supervised by Professor Kim, Heung-Geun) Abstract) This paper presents a novel cascaded multilevel PWM ac-ac converter that can solve commutation problem. By cascading the single-phase PWM ac-ac converter that uses basic switching cell structure and coupled inductors, the proposed converter does not need to sense the voltage or current polarity for safe commutation. When many unit-cells are cascaded, the proposed converter has more output voltage levels and can obtain high ac output voltage by using low voltage rating switching devices. By applying phase-shifted PWM technique, the proposed converter can reduce output filter size significantly. A 2 kW prototype converter having four unit-cell structure is built and tested to verify the performance.

Novel Current-Mode AC/AC Converters With High-Frequency AC Link-Daolian Chen-Power Electronics Research Institute, Fuzhou University, Fuzhou

Abstract—A novel circuit-topology family of the current-mode ac/ac converter with high-frequency ac link, based on a Flyback converter, is proposed. These circuit topologies, which can transfer one unregulated sinusoidal voltage with high total harmonic distortion (THD) into another regulated constant-frequency sinusoidal voltage with low THD, are composed of input cycloconverter, high-frequency storage transformer, and output cycloconverter. The circuit-topology family includes single fourquadrant power switch mode, push–pull mode, half-bridge mode, and full-bridge mode circuits. The single four-quadrant power switch mode and push–pull mode converters are suitable for low input voltage fields, but the half-bridge mode and full-bridge mode converters are suitable for high input voltage fields. The operational mode, steady principle, and transient voltage feedback control strategy of the kind of converter are investigated. The output characteristic curve, its relation to internal resistance, and the design criteria for the key circuit parameters are given. The theoretical analysis and the test result of the 500 VA 220 V ± 15% 50 HzAC/220 V 50 HzAC prototype have shown that the converters have advantages such as high-frequency galvanic isolation, simple topology, two-stage power conversion [low frequency alternating current (LFAC)/high frequency alternating current (HFAC)/LFAC], bidirectional power flow, high efficiency, high power density, low THD of the output voltage, strong adaptability to various loads, higher line power factor, low audio,noise, etc.

POWER ELECTRONICS M.D. SINGH - K.B. KHANCHANDANI

LINK DEMO BOOK GOOGLE:
http://books.google.co.in/books?id=0_D6gfUHjcEC&lpg=PP1&hl=pt-BR&pg=PP1#v=onepage&q&f=false
LINK DEMO BOOK  google PDF
https://copy.com/pb0Jh0TNRfHk4nZ0

ESS- Engineering Simulation and Scientific Software

A Engineering Simulation and Scientific Software surgiu com o objetivo de estabelecer um elo entre a produção científica desenvolvida nas universidades e a aplicação deste conhecimento na indústria, trazendo ao mercado o dinamismo e o espírito investigativo do meio científico, além da busca constante pela excelência na qualidade de seus serviços. Criada em 1995, a partir do Laboratório de Simulação Numérica em Mecânica dos Fluidos e Transferência de Calor da UFSC, renomada universidade federal brasileira, a ESSS iniciou suas operações com o desenvolvimento de softwares customizados para diversos setores do Centro de Pesquisas da Petrobras, com o qual realiza até hoje atividades de P&D nas áreas de exploração, produção, refino e distribuição de petróleo e derivados. Atualmente, mais de 300 profissionais de 50 departamentos da Petrobras utilizam as soluções fornecidas pela ESSS e uma média de 200 profissionais da estatal participam anualmente dos treinamentos oferecidos pelo Instituto ESSS de Pesquisa, Desenvolvimento e Educação. No total, a ESSS possui mais de 500 instituições como clientes nos mais diversos segmentos da indústria sul-americana, entre os quais de óleo e gás, aeroespacial, automotivo, metal-mecânico, geração de energia, turbomáquinas, processos químicos e mineração.

ATUAÇÃO INTERNACIONAL Desde que surgiu, a ESSS mantém um crescimento orgânico e vem conquistando importantes prêmios de inovação tecnológica. Além disso, realizou parcerias técnicas e comerciais com empresas globais de Computer Aided Engineering (CAE) e tornou-se o centro de excelência ANSYS no Brasil e na América do Sul. Ao longo dos anos, a ESSS ganhou destaque internacional por oferecer ao mercado soluções completas de modelagem matemática e simulação computacional e expandiu suas instalações para Argentina, Chile, Colômbia, Estados Unidos e PERU.
LINK
http://www.esss.com.br/empresa_conheca_a_esss.php