A Parameter-Centric Approach for Enhancing Misalignment Tolerance in Wireless Power Transfer Systems

This article introduces a misalignment tolerance design method for wireless power transfer (WPT) systems by optimization of compensation network parameters. Leveraging the derivation of two-port impedance parameters and adjoint sensitivity analysis, the coupling misalignment characteristics of the system are assessed. Subsequently, a parameter-centric misalignment tolerant approach, independent of the coil structure, is established through a linear fitting method. The proposed approach ensures zero-voltage switching (ZVS) and facilitates efficient stable constant current (CC) output. Experimental validation is performed on a scaled-down 500-W rated SS-compensated WPT prototype equipped with nonspecialized square-shaped coils, demonstrating the effectiveness of the proposed approach. The proposed method enhances the SS-compensated system's ability to tolerate both horizontal and vertical misalignments, surpassing the performance of conventional SS topologies. Specifically, the system achieves over 85% efficiency within the misalignment tolerance range, with a peak efficiency of 93.2%. Additionally, the load current variation remains within 5.8% for 100 mm $x$-misalignment and $-$15 to $+$50 mm $z$-misalignment.