Quasi-resonant Zero Voltage Switching Modified Boost Converter

Abstract

To reduce the switching losses in a DC/DC converter the quasi-resonant concept can be applied to the converter. With an additional resonant capacitor and an additional resonant inductor, the voltage across or the current through the electronic switch is influenced, so that the switching of the transistor can be done at zero voltage or zero current. The zero voltage switching concept is applied to the modified Boost converter. The modification concerns the position of the bulk capacitor. It is not connected between the output terminals but between the positive input and output connectors. This reduces the voltage stress of the capacitor and avoids the inrush current when connected to a stable DC grid or large batteries. The converter is explained step by step with the help of equivalent circuits and calculations. A very instructive method to analyze resonant circuits is the uZi diagram which is also applied. LTSpice simulations are used to prove these considerations.