Design of Different Symmetrical Bidirectional WPT Topologies Based on CC and CV Operating Modes for V2G Applications

Abstract

Electric vehicles (EVs) usually consume energy from the grid, and can also act as a distributed energy resource and feed energy back to the grid (V2G). Bidirectional wireless power transfer (BiWPT) is a viable approach for such an application since it facilitates automatic, safe, and reliable operation. Usually, topologies like SS, LCL-LCL, and LCC-LCC are preferred for BiWPT due to their symmetrical primary and secondary side compensation structures. All these topologies also have load-independent resonance. However, the inverter current in LCL and LCC-based topologies contains harmonics, which leads to higher VA loading on the inverter. Also, due to the higher peak current, the required tuning inductor size increases. This paper reports the conventional designs of SS, LCL-LCL, and LCC-LCC compensated BiWPT topology, which can provide only constant current (CC) output. This paper proposes the constant voltage (CV) mode of design for the LCL topology with a novel design that ensures significantly lower harmonics in the inverter output current. Also, a comparative study based on the harmonic content in the inverter current of different BiWPT compensation topologies under CC and CV modes of design is included to show the superior performance of the proposed design for V2G applications.