Optimized design of a fully soft-switched boost-converter suitable for power factor correction

A fully soft-switched boost-converter using a one auxiliary switch is presented here. It uses the minimum number of components in the auxiliary circuit with minimum current stress of the main switch. Since the resonant capacitor charges only through an inductor and a diode, the circuit conduction losses are minimized. The main and auxiliary insulated gate bipolar transistor (IGBT) switches share a common emitter connection, facilitating direct drive to them. Various operating modes of the converter are presented in detail and analysed. The choice of the resonating capacitor and inductor has been done through an optimization process based on the guiding equations working under different modes. In this optimization process, emphasis has been given on minimum voltage stress on the auxiliary switch for a wide duty cycle range of operation. Based on the design, the principle of operation has been verified with computer simulation. Experimental results from a laboratory prototype with active power factor correction confirms the operation of this converter.