Design, Analysis and Implementation of ZCS-ZVS Buck Converter with Auxiliary Circuit

Abstract

Now a day’s power converters are a basic need in technical fields. Power efficiency is the biggest challenge with the modern power converters. Higher efficiency, smaller size, and lighter weight modules lead to operate the converters in the high-frequency range. The problems generally associated with converters are switching and conduction losses. Converter operating at high frequency causes a high grade of power loss making it inefficient. These losses occur due to overlapping of voltage and current during the transition interval. In this thesis ZVS- ZCS soft switching skill is implemented using the buck converter along with auxiliary circuit for reducing the losses. The inclusion of auxiliary circuit improves the switching losses but at certain increased cost.
In this thesis a soft switching technique has been done including simulation and implication to improve the efficiency of isolated and non-isolated power converter operating in the highfrequency range. The designed converter uses two switches which operates in different switching schemes i.e., zero voltage switching (ZVS) and zero current switching(ZCS).both the switching schemes has advantage of increased efficiency of the buck converter with respect to hard switching. The pulse width modulated signals are generated sequentially with a delay circuit in open loop circuit. The auxiliary circuit has advantage of its operation in both isolated and non isolated converter. The operating principle, mathematical equations, MATLAB/SIMULINK simulation and results of ZCS-ZVS buck converter has been discussed. A 12 V, 35-watt buck converter has been implemented to validate the simulation results obtained.