| Summary: | 博士 === 國立成功大學 === 電機工程學系碩博士班 === 90 === In this dissertation, various integrated AC/DC converters with power factor correction and nondissipative snubber are discussed. A novel integrated AC/DC converter with power factor correction and line-frequency ripple suppression is proposed. And a novel nondissipative snubber integrated with AC/DC converters is also proposed.
The proposed topology combines an integrated flyback and forward circuits with a post regulator. The integrated flyback and forward circuits function as two sub-converters that share the total output power. To maintain a high power factor, the flyback circuit delivers the major output power. The post-regulator with fast response to suppress line-frequency ripple controls the output voltage in constant. Therefore the proposed circuit can result in a good performance with fast dynamic response. Without the use of high voltage bulk capacitor or current sensor, the circuit features high power factor and low output line-frequency ripple in discontinuous conduction mode. The input voltage can be varied over the standard testing range (0.8-1.2 p.u.), it is suitable for home or industrial applications.
To improve the efficiency of AC/DC converters, especially operating in discontinuous conduction mode, an integrated nondissipative snubber is proposed. By the use of a multi-winding transformer, the novel nondissipative snubber can be integrated with flyback or proposed AC/DC converters. No additional magnetic core, active switching and driver are needed for the proposed integrated nondissipative snubber. Therefore the proposed topology improves the efficiency without over-dimensioning of parts and with very low cost. The theoretical analysis and experimental results are presented.
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