A Novel ZCS/ZVS Bidirectional DC-DC Converter for Energy Storage Applications

In this paper, a new soft-switched non-isolated bidirectional converter is proposed. This proposed converter is operated with soft-switching (zero current switching / zero voltage switching). It is implemented during the turn-on of main switching devices, with the addition of auxiliary resonant circuit that consists of an auxiliary switch, diode, capacitor and an inductor. The switching losses are significantly reduced due to soft-switching operation of the main switches. Therefore, the efficiency of this topology is improved. The additional benefit of this topology is that the auxiliary switches are also operated with soft-switching. The proposed topology observes ZCS turn-on for boost mode and ZVS turn-on for buck mode operations. The principles of operation, design analysis and simulation verifications are discussed in detail. The soft-switching capabilities are obtained from design simulations on the 150V/250V/500W converter system.