Abstract:

Wireless electric vehicle charging (WEVC) emerges as a promising technology due to convenience characteristics and the mitigation of range anxiety to enable e-mobility. Recently, the safety issues on WEVC systems have drawn considerable attention. In light of thermal safety, the most critical part of WEVC systems is the surface of ground assembly (GA). During the charging process, its temperature increases due to the power losses, possibly resulting in cutaneous injury to living bodies and the ignition of foreign objects. Especially when there are evitable misalignments between the GA and vehicle assembly, its temperature rise will be higher as a penalty of efficiency deterioration of WEVC systems. Unfortunately, it has rarely been deemed as a safety hazard yet. Taking a commercialized WEVC system rated at 6.6 kW as an example, this paper focuses on the safety assessment of GA surface. The temperature distribution of GA surface is obtained using transient-state FEM (finite element method) simulations. Four hazard thresholds are recommended as evaluation criteria, based on IEC requirements. Finally, the calculated accuracy is experimentally validated. The findings indicate a clear impact of misalignments on the increase in temperature. Sensitivity to the temperature increase of various misalignments is also analyzed.