A Bidirectional Power Converter for Electric Vehicles in V2G Systems

Focused on the rational utilization of large-scale electric vehicle energy storage medium, the bidirectional and efficient power converter technique is important for the vehicle-to-grid (V2G) system. This paper explores the structure design ways of reducing electrical stress of LLC resonant circuit components, presents a novel power converter topology with two-stage architecture and its control strategy. The voltage source PWM converter (VSC) is used as the front-stage, and the post-stage is composed of the symmetrical half-bridge (SHB) LLC resonant converter. The power flow is bidirectional between electric vehicle (EV) and the grid through the power converter proposed in this paper. It also has the advantages such as isolated, high efficiency, high power density, small size, wide output voltage range, good dynamic performance and low cost. The operational theory and control strategy of the power converter are introduced respectively. The validity of the proposed concept is verified by simulations and experimental results.