Capacitor Tuning of LCC-LCC Compensated IPT System With Constant-Power Output and Large Misalignments Tolerance for Electric Vehicles

Inductive-power-transfer (IPT) is widely used in wireless charging of electric vehicle (EV). However, the output power and efficiency of the IPT system are often affected by misalignments. In this article, a double-side-
LCC
(
DLCC
) compensation network with switch-controlled-capacitors IPT topology is proposed to improve the misalignments tolerance for EV. First of all, the output power models of DLCC-SCC IPT system under tuned and detuned conditions are derived. Second, the best choice of selecting adjustable capacitors for regulating the output power is analyzed. Then, an optimal control strategy for DLCC-SCC IPT system that maintains constant-power (CP) output and zero-phase-angle (ZPA) under large misalignments is designed. Moreover, since the output control is only implemented in the transmitting side, wireless communication can be omitted. Finally, an experimental prototype with 330 W is built to verify the effectiveness of the proposed scheme. The results shows that the CP with ZPA can be achieved under significant misalignments, i.e., the coupling coefficient changing from 0.175 to 0.075, meanwhile, the measured efficiencies can be maintained at 88.13%–88.3%.