AC-DC Power Converter with Unity Power Factor

• Main Authors: Jhang Jian Jyun -Yi, 張簡駿逸
• Other Authors: Wu Jinn-Chang
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/42464490460403641181

碩士 === 國立高雄海洋科技大學 === 微電子工程研究所 === 101 === In this paper, an AC-DC power converter with unity power factor is proposed. The proposed AC-DC power converter is configured by two cascade–connected power factor correctors, a buck power converter and a forward power converter. One of power factor correctors is switched in high-frequency pulse-width modulation, and the other one is switched in the frequency the that of input AC voltage. Accordingly, the cascade operation of two power factor correctors can generate a five-level AC voltage in the input terminal so as to reduce the capacity of input filter. As compared with the conventional power factor corrector, the output voltage of power factor corrector in the proposed AC-DC converter is reduced by half. Thus, the switching voltage of high-frequency power factor corrector is also reduced by half. Hence, the switching power loss of high-frequency power factor corrector is reduced and the electromagnetic interference of AC-DC power converter is alleviated. In addition, the input current of AC-DC power converter will be controlled by the high-frequency power factor corrector to be a sinusoidal waveform in phase with the input AC voltage so as to attain unity power factor. The buck power converter and the forward power converter are applied to integrate the output voltages of power factor correctors to an output voltage supplying to the load. A prototype with a digital signal processor based controller is developed and tested to verify the performance of the proposed AC-DC power converter.