A soft-switching high gain DC–DC converter for renewable energy systems

Abstract

ABSTRACT In order to improve the efficiency of high gain DC-DC converter using MOSFET as switching device, a novel zero-voltage soft-switching high gain DC-DC converter is presented. A main switch tube is used to replace the output diode in the conventional boost converter, and an auxiliary network is added to make the two switches realise true ZVS soft turn-on and all diodes realise true ZCS soft turn-off, which improves the efficiency and effectively suppresses the negative effect of diode reverse recovery. Furthermore, the output end of the converter is composed of three output capacitors in series, which avoids the converter working at the limit duty cycle, increases the voltage gain and reduces the switch voltage stress. Therefore, MOSFET with low voltage level and low on resistance can be selected as switching devices. The resonant capacitor and leakage inductance are used to reduce the current at the turn-off time of the switch. The operating principle and steady-state characteristics of the converter are analysed in detail. The design idea of the main parameters is given, and the efficiency and loss of the converter are evaluated. Finally, the experimental results on a 100 W prototype show that the efficiency reaches 95.79% at rated power.