Zero-voltage and zero-current hybrid soft-switching phase-shifted PWM DC-DC power converter for high power applications

This paper presents a novel prototype version of zero-voltage switching (ZVS) PWM DC-DC power converter with a high frequency transformer link, which incorporates zero-current switching (ZCS) mode synchronous active power switches in series with each rectifier diode in high-frequency transformer secondary side. This converter circuit with an isolated high-frequency transformer link can achieve ZVS in transformer primary side and ZCS in transformer secondary side under the wide load variations. Using the proposed converter, switching and conduction losses of all the active power devices are reduced as well as circulating current flowing through a transformer link as compared with the previously-developed soft-switching converter with a phase-shifted PWM scheme in the high-frequency transformer primary side. The steady-state operating principle of this converter in the open loop system and voltage regulation characteristics are described and evaluated on the basis of the simulation analysis and some experimental results of 2 kW-40 kHz breadboard.