Novel Bidirectional Isolated DC/DC Converter with High Gain Ratio and Wide Input Voltage for Electric Vehicle Storage Systems

Abstract

This study proposes a novel bidirectional isolated DC/DC converter with a high gain ratio and wide input voltage for electric vehicle (EV) storage systems. The DC bus of an EV can be used to charge its battery, and the battery pack can discharge energy to the DC bus through the bidirectional converter when the DC bus lacks power. The input voltage range of the proposed converter is 24 to 58 V on the low-voltage side, which meets the voltage specifications of most servers and batteries on the market. The proposed topology is verified through design, simulation, and implementation, and voltage gain, voltage stress, and current stress are investigated. The control bidirectional converter is simple. Only one set of complementary signals is required for step-up and step-down modes, which greatly reduces costs. The converter also features a continuous current at the low-voltage side, a leakage inductance function for energy recovery, and zero-voltage switching (ZVS) on certain switches, which can prevent voltage spikes on the switches and increase the efficiency of the proposed converter. A bidirectional converter with a total power of 1 kW is used to verify the topology’s feasibility and practicability. The power at the low-voltage side was 24–58 V, and the maximum efficiency in step-up mode was 94.5%, 96.5%, and 94.8%, respectively; the maximum efficiency in step-down mode was 94.4%, 95.4%, and 93.7%, respectively.