A Hybrid Bridge Push-Pull Forward Resonant Converter With Fixed Frequency PWM Control for High-Reliability Application

This paper proposes a high reliability push-pull forward resonant converter for space power supply systems. The primary side of the converter consists of two series-connected forward converter units, and the secondary side incorporates a resonant tank in the semiactive variable-structure rectifier (SA-VSR), which adjusts the voltage gain range through fixed-frequency PWM control. By controlling the duty cycle of the bidirectional switch in SA-VSR, the proposed converter can operate in three modes: voltage doubling rectification (VDR) mode, full bridge rectification (FBR) mode, and PWM control mode, which can achieve a regulation of twice the voltage gain range. This paper provides a detailed working principle and voltage gain analysis of the converter. All switches of the proposed converter can achieve ZVS, and there is no issue of direct short-circuiting through the switches, making it highly reliable and appropriate for applications in aerospace. Finally, a prototype with a rated input voltage of 90-180V, output voltage of 400V, and output power of 800W is built to verify the effectiveness of the proposed converter.