New Fully Soft-Switched Boost-Converter with Reduced Conduction Losses

A new fully soft-switched boost-converter is proposed here, using only one auxiliary switch. All switches used in this converter turn on and turn off under fully soft-switched condition. The diodes also commutate softly. The converter uses minimum number of components in the auxiliary circuit without additional current stress of the main switch. The circuit conduction losses are also minimised, since the resonant capacitor charging current flows only through an inductor and a diode. The main and auxiliary IGBT share a common emitter connection, facilitating direct drive to them. The circuit is suitable for application to active power factor correction. Various operating modes of the converter are presented and analysed. The principle of operation has been verified with computer simulation and experimental results.