Improved interoperability evaluation method for magnetic coupler of wireless EV charging

Abstract:

The interoperability of different assemblies is an essential factor affecting the popularization of wireless electric vehicle charging technology. Interoperability refers to the ability of the system to output rated power with specified efficiency when different ground and vehicle assemblies are paired. Aiming at the problems of incomplete evaluation criteria and low accuracy of evaluation results, this paper introduces the detuning factor and load factor representing the system resonance and load, respectively, and proposes an interoperability evaluation method based on two factors. Firstly, the limitations of the traditional evaluation method based on interface impedance are revealed. Secondly, the relationship between the detuning/load factors and system power, efficiency, and current limits are established. Then, according to the limits specified in national standards, the two factors’ interoperable region and its boundary functions are deduced, and the interoperability evaluation criterion based on the two factors is obtained. Experiments show that the proposed method can evaluate interoperability comprehensively from output power, system efficiency, and current limits. It not only solves the problem of incomplete evaluation criteria in the traditional method, but also improves the accuracy of interoperability evaluation results.