3-Coil resonance structure wireless power transfer for 5kV implantable device

Compared to 2-coil structure wireless power transfer (WPT), the 3-coil resonance structure WPT for an implantable device has a lower primary current when output the same voltage. An output voltage curve is drawn based on the changes of the primary and secondary coil inductances using the simulation software. In this WPT system, the primary side employs the resonant structure to enhance the electromagnetic field and the secondary side employs an inductive coupled structure to avoid huge heat. 3-coil structure is proved to have a higher efficiency compared to the 2-coil structure from the simulation result. The DC output voltage reaches up to 5kV and the efficiency is more than 35% when the transfer distance is 3cm.