Efficiency improvement of two coil wireless power transfer system for biomedical implants

Wireless power transfer system is used to charge the batteries of biomedical implants. This article presents a design of two coil system which is able to transfer the power to the implanted battery without any tissue damage. One module consists of primary coil and alternating signal generator circuit and the other consists of secondary coil, DC-DC converter and control circuit. External coil is used to transfer the power through magnetic link. The whole idea is to recharge the battery of implants. In this research work two coil inductive system with two different strategies, one is field focusing element(repeater) and second is ferrite magnetic core to enhance the magnetic field at same distance and same frequency are compared. In the prototype of two coil power transfer system, 575 kHz and 700 kHz frequency with different signals are used for driving the primary coil with 68 mm diameter and coil distance 10 mm to 50 mm using 18 mm implanted coil diameter and achieved more than 40% efficiency at 30 mm distance which is better results compared by conventional two coil system.