A Coil Misalignment Compensation Concept for Wireless Power Transfer Links in Biomedical Implants

Inductively coupled wireless links are attractive solutions for wireless powering of biomedical implants. One of the issues that negatively impacts the performance of wireless power transfer (WPT) links in implants, is the misalignment between the primary and secondary coils, which could naturally occur as a result of body movement or changes in the biological environment. An immediate effect of coil misalignment is the reduction in the power delivered to the load. In this paper, we present a design concept that could be implemented on the transmitter side, to mitigate this effect while keeping the driver to work at its optimum operating condition. Specifically, we will demonstrate, analytically and through simulations, that tuning the shunt capacitor and the supply voltage at the transmitter side could be a promising approach for compensating the performance degradation induced by coil misalignment in WPT links.