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

This article presents a hybrid full-bridge for high efficiency in a wide output voltage range, 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 a 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 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.