A bipolar receiver pad in a lumped IPT system for electric vehicle charging applications

Inductive Power Transfer (IPT) has proved its capability as a safe, convenient and efficient solution for electric vehicle (EV) charging systems by providing sufficient power levels with tolerance to lateral displacement. The magnetic design of the receiver/secondary and transmitter/primary pads is the most critical part of an IPT system design. This paper presents the performance of a Bipolar Pad (BPP) receiver in a lumped IPT system for EV charging systems and compares it against the performance of a recently proposed receiver design, Double-D Quadrature Pad (DDQP). A 3D finite element modeling tool, which has shown good agreement between measured and simulated results in the past, is used to simulate all the models presented in this paper. The prototype models are also built and tested to verify the simulated results. Although it has been shown that the polarized single sided flux pad design, Double-D Pad (DDP), has much better performance than the non-polarized single sided flux pad design, Circular Pad (CP), still the ability of a receiver pickup to interoperate with both types of transmitters is considered to be highly desirable. In this paper the performance of a BPP receiver is compared against the performance of a DDQP receiver when used with either a DDP transmitter or a CP transmitter. The results show that the BPP receiver approximately matches the output levels provided by a DDQP receiver while using less amount of copper. Finally, the possibility of improving the ability of both the BPP and DDQP receivers to interoperate with both DDP and CP transmitters by changing the receiver ferrite structure is investigated. The results however indicate that for both the BPP and the DDQP receiver designs, the traditional ferrite structure exhibits best material usage efficiency amongst the design possibilities considered in this paper.