An Integrated Power Decoupling Method for Single-Phase EV Onboard Charger in V2G Application

Instead of bulky passive filters, the active power decoupling (APD) method can be adopted to suppress the 2nd-order ripple power in the DC-bus of the single-phase electric vehicle (EV) onboard charging system. However, the traditional APD methods require additional power switches and energy storage devices, which increases the cost and significantly reduces the power conversion efficiency. To tackle these problems, an integrated method of utilizing the auxiliary power module to form a series-connected APD circuit is proposed in this paper. Without additional switches and energy storage devices, the APD circuit only needs to compensate less than 10% of the rated power, while realizing soft-switching operation. In addition, the corresponding control method can further reduce the voltage stress of the switches on the high-voltage side of the converter, and increase the efficiency of the system. Finally, a 2kW single-phase charging system prototype is built to verify the feasibility and effectiveness of the proposed method.