Pareto optimization of circular power pads for contactless electric vehicle battery charger

Design optimization of circular power pads for inductive power transfer (IPT) systems with applications in electric vehicle battery charger is proposed. A multi-objective optimization coupled with 2D finite element analysis (FEA) is used to find the Pareto-optimal solutions for circular magnetic structures considering different objective functions, such as power transfer efficiency, material cost, and horizontal misalignment tolerance of the IPT system. 2D FEA is used to calculate self and mutual inductances between primary and secondary pads, ohmic loss in coils, core loss in ferrites, stray loss in aluminum shields and electromagnetic field (EMF) emissions of the system. Practical limitations of the power electronic converters such as frequency, VA rating, operating quality factor, and EMF emissions are all considered in the proposed optimization. A 10 kW electric vehicle battery charger IPT system with circular power pads is investigated as the case study and Pareto-optimal solutions for this system are presented. Experimental test results on one of the Pareto-optimal solutions are in good agreement with the calculations using the proposed method. The proposed design optimization method provides a tool for finding highly efficient, flexible and cost-effective solutions for contactless electric vehicle battery charger.