| Summary: | 碩士 === 國立臺灣科技大學 === 電子工程系 === 98 === This thesis aims to study a dual-mode boost-type active power factor corrector (PFC), Under light-load condition. the circuit is operated at a Quasi-Resonant (QR) mode or a Boundary Conduction Mode (BCM) to reduce switching losses. Otherwise. the circuit is operated at Continuous Conduction Mode (CCM) under heavy load condition to reduce the device current stresses.
Firstly, the operation principles and the zero-voltage switching condition for an ideal power factor correction are analyzed and discussed. Then, two 300W dual-mode boost-type power factor correctors are built and tested to verify the above theoretical analysis, The control circuits of the laboratory prototypes are implemented by using the Texas Instruments chip UC 3854 and external auxiliary circuits, The experimental results are shown to verify the feasibility of the studied schemes. High conversion efficiency can be achieved under light-load conditions and device current stresses can be reduced effectively under heavy-load conditions.
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