Core Design and Optimization for Better Misalignment Tolerance and Higher Range of Wireless Charging of PHEV

In this paper, a design and optimization method of ferrite core is proposed for wireless charging system of plug-in hybrid electric vehicle to improve its misalignment tolerance and minimize the core loss. While optimizing for higher misalignment tolerance, the primary focus is given to maintain uniform flux density in the core to minimize the core loss. An excessive use of core increases the weight and loss of the system, which need to be minimized through optimal design. Moreover, the flux density changes with misalignment, and the misalignment probability for car parking could be different in different direction. Hence the directional probability of misalignment needs to be considered during core design. In this paper, a core structure is proposed for a circular and bar-shaped core to achieve uniform flux density and an optimization method is proposed based on sequential nonlinear programming algorithm in FEA. Compared to typical uniform thickness core structure, in an optimized core, the core loss per unit volume is reduced by 30% for circular core and by 39% for bar-shaped core and the core volume per unit core loss is reduced by 17.5% in optimized circular shaped core.