Improved active power factor correction circuit using a fully soft-switched boost converter

An improved fully soft-switched boost converter for active power factor correction is presented here. The converter uses an auxiliary circuit consisting of a switch, one inductor, a resonating capacitor and a diode. Unlike several earlier solutions, all switches used in this converter turn on and turn off under fully soft-switched condition. The boost diode also commutates softly and the auxiliary diode operates under soft-switched condition. The main switch of the converter does not suffer from additional current stress. Moreover, the main and auxiliary switches share a common emitter connection, facilitating direct drive to them. Various operating modes of the converter are presented and analysed in detail. The performance of the converter has been verified by means of computer simulation and experimental results.