| Summary: | 碩士 === 國立中央大學 === 電機工程研究所 === 93 === Three-phase ac voltage regulator is capable of providing regulated power source, and one of the important issues of it is to stabilize the power quality. In this paper, a novel switching strategy called phase-shift pulse width modulation is applied to the three-phase four-wire ac voltage regulator（AVR）which utilizes a YY connection for the purpose of enhancing output power rating. The system is made up of three ac choppers with reversible voltage, AVR motherboards and transformers for series voltage compensation. The switching strategy is to match up the components of the system as mentioned above such that the compensation voltage with the same or opposite polarity for the input utility voltage can be simply obtained by controlling the duty cycle of power devices. Consequently, variations of the output voltage would be compensated or restrained. The fast sensing technique is adopted toward output voltage and the control law is implemented through the fixed-point digital signal microcontroller（DSM）（dsPIC30F2010）. The system is able to improve reliability, response, efficiency, power factor and reduce cost. It is shown via the experimental results that the system achieves the expected goal of fast voltage regulation.
|
|---|
