Wireless Power Transfer System With Adaptive Current Following of Repeater Coils

In this paper, an exciter-quadrature-repeaters transmitter pad is proposed to achieve high two-dimensional misalignment tolerance of the wireless power transfer system. In the proposed wireless power transfer system, an inverter unit is needed to energize the exciter coil, which is magnetically coupled to three quadrature repeater coils. The currents in the three repeater coils naturally adjust based on the two-dimensional misalignment of the receiver pad to reduce the leakage flux density around the charging zone. The system can maintain the phase shift close to zero between excitation voltage and current and achieve constant current charging conditions with fixed compensation capacitors in the ± 50 mm two-dimensional misalignment range. According to the simulation results, the proposed wireless power transfer system has a near system efficiency and lower leakage flux density in extreme ± 50 mm two-dimensional misalignment case compared to the two-coil system.