Soft switched low stress high efficient ZVT PWM DC-DC converter for renewable energy applications

Abstract

With the growing global demand of green energy, the conversion of renewable energy sources into useful DC or AC power for residential and industrial applications is becoming more popular. To design and develop economic, high-efficient, compact and light weight power conversion systems is still a subject of research.Now-a-days, Power Electronic devices of smaller size are inevitable, which causes the switching frequency to jump from KHz to MHz range. The switching devices are made to turn on and turn off at high di/dt for the entire load current, and also to withstand high voltage stress across them. Due to these two effects, there occur increased power losses in the converters thus it reduces the efficiency significantly. In this paper a soft-switched low stress zero-voltage transition (ZVT) pulse width modulated (PWM) buck converter is proposed. Its operation modes are identified and analyzed. The developed converter can reduce the high voltage and high current stresses caused by the high input voltage across the resonant capacitor in the Zero Current Switching(ZCS) and Zero Voltage Switching (ZVS) converters. The proposed converter simulated in PSIM software and simulation results and waveforms for the proposed converter are presented. In addition, the proposed ZVT buck converter is compared with ZVS resonant buck-converter and the switching losses are compared under the same operating conditions and results are presented.