A Hybrid Inductive Power Transfer System With Misalignment Tolerance Using Quadruple-D Quadrature Pads

Pad misalignments are almost inevitable in most inductive power transfer (IPT) systems. It tends to cause parameter variations and, thus, significantly affects the performance of the IPT system. In this article, a hybrid IPT system with misalignment tolerance using the quadruple-D quadrature pads (QDQPs) is proposed to tolerate the x, y, z, and diagonal misalignments with load-independent output voltage, simplifying or even canceling control schemes. Besides, the proposed approach can restrict the increase of the primary current when the secondary side moves out of the operating region. Moreover, a new parametric design method is presented according to the misalignment characteristics of QDQPs. The method can limit the output voltage fluctuation to a certain range, given a predetermined misalignment distance. A 3.5-kW prototype was built to verify the proposed hybrid IPT system. The primary and secondary coil sizes are 400 mm x 400 mm, and the air gap is 150 mm. Experimental results demonstrate that the proposed hybrid system can tolerate -150 to +150 mm x-misalignment,-150 to + 150 mmy-misalignment,-20 to + 35 mm z-misalignment, and -100 to +100 mm diagonal misalignment with load-independent output voltage. Within the predetermined misalignment range, the output voltage fluctuation is less than 5%.