Control of Wireless Power Transfer Systems under Large Coil Misalignments

Coil misalignment in wireless power transfer systems causes variation in self- and mutual inductances, resulting in reduction in power throughput at increased losses. This paper proposes a P-Q based primary side controller that regulates output voltage while minimizing losses under coil misalignment or load variations. The proposed controller varies the frequency of the converter to restore the tuned operation under coil misalignment while avoiding bifurcation and simultaneously regulating the output voltage through primary phase-shift modulation. Both theoretical analysis and simulation results are presented to show the validity of the proposed control method, which does not require a secondary controller or a dedicated communication link.