An Efficiency Optimization-Based Asymmetric Tuning Method of Double-Sided LCC Compensated WPT System for Electric Vehicles

Compensation topologies play an essential role in wireless power transfer systems for electric vehicles. Specifically, the double-sided LCC compensated (DS-LCC) topology has been widely adopted, owing to its inherent advantages, such as load-independent constant current (CC) output, low sensitivity to load variation, and high freedom in parameter design. However, large resonant devices in the DS-LCC topology lower the system efficiency and increase the complexity of optimal parameter tuning. Therefore, in this article, the parameters of the DS-LCC compensation topology are reconfigured by adjusting the ratios of its two compensation inductances without changing the specified system-level parameters, such as the loosely coupled transformer, operating frequency, and specified CC outputs. The system performance under each case is analyzed and compared in detail, based on which, an asymmetric parameter-design method is proposed to optimize the system efficiency. To verify the reasonability of the proposed tuning method, a 6.6-kW experimental prototype is configured, and comparative experiments are conducted. The experimental results indicate that, compared with the conventional method, the proposed parameter-tuning method improves the system efficiency under overall load conditions, especially under light loads.