A high power density and efficiency bi-directional DC/DC converter for electric vehicles

In electric vehicle systems, bi-directional DC/DC converters are used to interface the battery bank with the high voltage DC bus of the inverter. The high power density and high efficiency are required for bidirectional DC/DC converters. This paper discusses the relationship between switching frequency, inductor value and passive components volume. First, the topologies of the system and the converter are presented. Then, the loss breakdown model is provided. A selection for the switching frequency is presented and an option of inductor value is provided to reduce the converter size and to keep the converter efficient. Then the converter layout which further enhances the power density is discussed. Finally, a high power density and high efficiency converter prototype is built, and the efficiency and thermal performance evaluation of the converter at different operating conditions is given.