三相交流穩壓器具有穩定電源之功能，故電源品質的穩定是一個重要的課題。本論文應用一種新型相移脈波寬度調變的切換控制方式，並實現應用在Y-Y三相四線式架構之交流穩壓器上，以提高三相交流穩壓器之輸出功率。此系統包含三組電壓極性可逆之交流截波器、交流穩壓器主控電路板與串聯補償變壓器，並配合其切換方式，只需簡單地控制開關切換的責任週期，就可以得到與輸入市電同極性或反極性的電壓，進而補償或抑制市電的變動。並使用快速輸出電壓偵測、定點式數位訊號控制器（dsPIC30F2010）來實現控制法則，以提高本系統的可靠度、系統響應、效率、功率因素與降低成本。經實驗證明，本系統可以達到快速穩壓之預期目標。 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.
