| Summary: | 碩士 === 國立成功大學 === 電機工程學系碩博士班 === 94 === Recently, high-frequency active power factor correction (PFC) circuits have been extensively applied to various electric products, such as switching power supply and various lighting equipments. High frequency PFC circuits provide benefits such as small size, high power factor, low total harmonics distortion, etc. However, there are several inherent drawbacks, e.g. serious electromagnetic interference (EMI) problems and complex compensator design. The regulation of the power quality for home appliances such as air conditioner, refrigerator, washing machine, etc., is not as strict as lighting equipments. Therefore, the high frequency PFC circuits may not be the best solution when considers the cost, volume, and regulation for most variable speed control home appliances. This thesis presents a high power factor and low current harmonic distortion PFC circuit based on the so-called low-frequency asymmetric pulse width modulation (Asy-PWM). Compared with the high frequency PFC circuit, the proposed method has several advantages, such as easy to control/implement, high reliability, and elimination of the heavy EMI filters. Moreover, it is complied with the IEC 1000-3-2 regulation. These attractive features suggest that the proposed method is very suitable for most variable speed control home appliances. The theoretical analysis, computer simulation and experimental results have demonstrated the effectiveness of the proposed method.
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