Efficient Hybrid Dual Full-Bridge DC–DC Converters for Pulsed Output Current Applications

Abstract

This paper presents a hybrid full-bridge DC-DC converter for a wide output voltage range in high efficiency, especially for pulsed output current applications. For the conventional phase-shift-full-bridge DC-DC converter, the hard switching and circulating current lower the efficiency in the wide output conversion ratio. To improve the efficiency of the DC-DC power supply for the pulsed output current, a hybrid DC-DC converter is proposed. On the primary side, two full bridges are integrated by sharing a bridge leg. The circuit on the secondary side is a hybrid rectifier stage. For the pulsed output current with a constant load resistor, a single full bridge works in the low output current. For the large output current, the hybrid two full bridges work together. The circulating current in the hybrid working mode is reduced by a blocking capacitor. The converter is controlled by the phase shift and duty cycle control. All the switches work in zero voltage switching. A prototype is built to verify the performance and control strategy of the converter.