"OBRIGADO DEUS PELA VIDA,PELA MINHA FAMILIA,PELO TRABALHO,PELO PÃO DE CADA DIA,PROTEGENOS DO MAL"
“SE SEUS PROJETOS FOREM PARA UM ANO,SEMEIE O GRÂO.SE FOREM PARA DEZ ANOS,PLANTE UMA ÁRVORE.SE FOREM PARA CEM ANOS,EDUQUE O POVO.”
“Sixty years ago I knew everything; now I know nothing; education is a progressive discovery of our own ignorance. Will Durant”
segunda-feira, 12 de agosto de 2013
domingo, 11 de agosto de 2013
quinta-feira, 8 de agosto de 2013
ÔNIBUS ELÉTRICOS são recarregados, sem fios, enquanto andam pelas ruas
Imagine um veículo elétrico que pode viajar por distâncias infinitas sem jamas ter que parar em uma estação de recarga. Parece impossível, certo? Porque veículos elétricos usam baterias e, em algum ponto, você precisa parar para recarregá-las. Mas não esta aqui.
Dois novos ônibus elétricos que começaram a rodar nas ruas da cidade de Gumi, Coreia do Sul, tiram energia do asfalto. Os chamados Veículos Elétricos Online (OLEV, na sigla em inglês) recebem energia, sem o auxílio de fios, vinda de cabos elétricos colocados embaixo da superfície das ruas usando a tecnologia Shaped Magnetic Field in Resonance (SMFIR). Os ônibus levam uma bateria que tem um terço do tamanho das tradicionalmente usadas por carros elétricos e a recarrega coletando o equivalente a 100 kW de eletricidade desses campos magnéticos criados pelos cabos elétricos — eles trafegam a cerca de 17cm da superfície das ruas.
Pesquisadores têm grandes expectativas para a tecnologia, originalmente desenvolvida pelo Instituto de Ciência e Tecnologia Avançada da Coreia (KAIST).
quarta-feira, 7 de agosto de 2013
segunda-feira, 5 de agosto de 2013
domingo, 4 de agosto de 2013
A High Performance DSP Voltage Controller with PWM Synchronization for Parallel Operation of UPS Systems
A High Performance DSP Voltage Controller with PWM Synchronization for Parallel
Operation of UPS Systems
Kyung-Hwan Kim
Hanyang University
Department of Electrical Engineering
17 Haengdang-dong, Seongdong-Gu, Seoul KOREA
Inverter system, which uses LC component as the output filter, is essential for a UPS (Uninterruptible Power supply), UPQC (Universal Custom Power Conditioner) and PCS (Power Conditioning System) for the photovoltaic power system. This paper presents DSP (Digital Signal Processor) controlled voltage controller for a 3-phase UPS inverter, which is able to compensate the voltage distortions due to unbalanced and nonlinear loads. The paper discussed the problem of conventional control schemes for the compensation of voltage distortion when they are applied to UPS inverter, and proposes advanced synchronous reference frame control scheme which is able to overcome the problem. In order to solve the problem of low damping ratio of LC filter, the inverter current feed-forward compensator including the selection of the feed-forward gain is proposed. And the digital filter for a compensation of the voltage distortion due to unbalanced and nonlinear loads is also proposed, which makes PI controllers in the synchronous reference frame are able to operate with DC values even under nonlinear and unbalanced load, likewise ensures PI controllers are able to provide zero steady state error. In order to improve the practical usability of the proposed scheme in the paper, the realization of the PLL and the parallel operation, which are essential for UPS, using the proposed controller is also presented. Especially, this paper shows that the feed-forward compensation of the inverter current and the PWM synchronization method proposed in the paper ensures a high precise load-sharing performance in parallel operation of inverter system.
Operation of UPS Systems
Kyung-Hwan Kim
Hanyang University
Department of Electrical Engineering
17 Haengdang-dong, Seongdong-Gu, Seoul KOREA
Inverter system, which uses LC component as the output filter, is essential for a UPS (Uninterruptible Power supply), UPQC (Universal Custom Power Conditioner) and PCS (Power Conditioning System) for the photovoltaic power system. This paper presents DSP (Digital Signal Processor) controlled voltage controller for a 3-phase UPS inverter, which is able to compensate the voltage distortions due to unbalanced and nonlinear loads. The paper discussed the problem of conventional control schemes for the compensation of voltage distortion when they are applied to UPS inverter, and proposes advanced synchronous reference frame control scheme which is able to overcome the problem. In order to solve the problem of low damping ratio of LC filter, the inverter current feed-forward compensator including the selection of the feed-forward gain is proposed. And the digital filter for a compensation of the voltage distortion due to unbalanced and nonlinear loads is also proposed, which makes PI controllers in the synchronous reference frame are able to operate with DC values even under nonlinear and unbalanced load, likewise ensures PI controllers are able to provide zero steady state error. In order to improve the practical usability of the proposed scheme in the paper, the realization of the PLL and the parallel operation, which are essential for UPS, using the proposed controller is also presented. Especially, this paper shows that the feed-forward compensation of the inverter current and the PWM synchronization method proposed in the paper ensures a high precise load-sharing performance in parallel operation of inverter system.
A New Equivalent Circuit Model of IGBT Current Sensors Chun-Chieh Tseng* Chia-Hsiung Kao**
A New Equivalent Circuit Model of IGBT Current Sensors
Chun-Chieh Tseng* Chia-Hsiung Kao**
ABSTRACT
A new equivalent circuit model for IGBT is presented. It takes into account both
electron and hole conduction in sensors and is incorporated with SPICE3 for the
simulation of three types of current sensors, namely active, bipolar, and MOS sensors.
It adopts a multi-MOS model to include the doping variation in the MOS body. The
results agree well with the current sensing measurements within an average error of
4.4%.
LINK FULL PAPER HERE :
Chun-Chieh Tseng* Chia-Hsiung Kao**
ABSTRACT
A new equivalent circuit model for IGBT is presented. It takes into account both
electron and hole conduction in sensors and is incorporated with SPICE3 for the
simulation of three types of current sensors, namely active, bipolar, and MOS sensors.
It adopts a multi-MOS model to include the doping variation in the MOS body. The
results agree well with the current sensing measurements within an average error of
4.4%.
quinta-feira, 11 de julho de 2013
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