Analysis and Experimental Verification of an Isolated Half-Bridge Bidirectional DC-DC Converter

This article describes the analysis of a zero voltage switched isolated bidirectional half-bridge active-clamp current-fed push--pull converter for a power in the range of 1 kW. Combining the beneficial characteristics of active-clamping and advanced control scheme, this converter realizes soft-switching features for a hard-switching converter design. The technique utilizes the inductance and the clamp capacitor on the lower voltage (LV) side to create zero voltage switching conditions for the transistors on the higher voltage (HV) side. Additional overvoltage stress, voltage spikes, and reverse-recovery for the transistors on the LV side are reduced. By using the advanced control scheme, the effective turns ratio can be increased. The operating principles are analyzed in time-domain and validated by measurements.