Single Phase Converter with Power Decoupling and Reactive Power Control for Bi-directional EV Charger

Abstract

In traditional single phase converters for EV chargers used in private cars, the power flow is only unidirectional, and the bulky and short-lifetime electrolytic capacitors are usually used to issue the second-order ripple power between the AC and DC side. To address the problem, this paper proposes a control strategy to enable the single phase EV charger to achieve both four-quadrant operation and power decoupling control at the same time so that the EVs can respond dispatching commands from the future smart grid as distributed energy resources, meanwhile the size of the charger can be reduced. This control method is based on our previous work, proposed novel topology of single phase converter using a small film capacitor to decouple the second-order power. The operation principle of the proposed control strategy is analyzed in detail, and the design method of decoupling capacitance for both power decoupling and reactive power control purposes is provided. Simulation results by MATLAB/Simulink are provided to verify the effectiveness of the proposed control strategy.