Design and Optimization of High-Gain Bidirectional DC–DC Converter for Electric Vehicles

To better leverage and cope with the characteristics of low-voltage electric vehicle battery pack, this work optimizes the design of on-board bidirectional dc–dc converter. Based on the dual active half-bridge (DAHB) converter, combined with partial switch sharing, a high-gain bidirectional dc–dc converter is proposed. This converter has 48-V and 24-V output voltage levels, and the multiple voltage levels, which are often required by new energy vehicles, are able to reduce the number of on-board converters. The theoretical part of this work analyzes the design process of the converter, and in parallel, establishes the mathematical models of transmission power, soft switching, current stress, and reactive backflow loss. Under the condition of high gain, the system has good soft-switching characteristics and low reactive backflow loss. In the experimental part, a prototype with an input voltage of 400 V is built under an operating frequency of 100 kHz. The voltage of the two output ports is stable and a peak efficiency of 94.7% is achieved. The experimental results verify the validity of the theoretical analysis.