Comparison of Compensation Topologies for Wireless Charging Systems in EV Applications

The core device of wireless power transfer system (WPTS) is a coupling transformer. The air gap between the primary and secondary coils will produce leakage inductance and magnetizing inductance, which reduces the output power and transmission efficiency. To compensate for leakage inductance and magnetizing inductance, a compensation network is needed. According to the different compensation methods, common compensation topologies are series-series (SS), double-side Inductor-Capacitor-Inductor (LCL) and double-side Inductor-Capacitor-Capacitor (LCC) compensation. In this paper, for these three common compensation topologies, through Matlab/Simulink, their transmission characteristics and anti-offset performance were analyzed, the results show that the SS-type compensation topology is suitable for high-frequency environments. The LCL-type compensation topology is more robust but not suitable for large power systems, while the LCC-type compensation topology maintains better robustness while the transmission power is significantly improved. Experimental platform is built to verify the transmission characteristics of the SS compensation topology.

I Introduction

With the development of power electronics technology, Wireless power transfer (WPT) enjoyed more attention and provided a new solution for energy harvesting of power equipment. [1]. The rapid development of power electronic devices enables wireless charging to be applied in real-world scenarios [2]. WPT system generally which adopts the principle of magnetic coupling resonance transfer the high-frequency AC electric power by magnetic couplers in space. And the compensation circuit is used to achieve high-efficiency transmission characteristics.