Development of Wireless Power Transfer

Abstract

Wireless power transfer in simple terms is the transferring of power (electrical power) from one source of power to the electrical load without using any type of man-made interconnection. Wireless power transfer can be said as a system of transferring electrical power through the air. The basic component used in wireless power transfer is the primary coil and secondary coil by using the induction theory. Where, AC current flow in the primary coil will induce amount of AC voltage in the secondary coil through the electromagnetic field between both coils. The AC voltage then can be used to power a device or charge a battery after converting the AC to DC voltage using bridge rectifier. Resonant circuits are used to enhance the inductive power transfer. Normally, simple inductions between two coils have a low coupling value and resonant capacitors are placed on the primary coil and secondary coil to improve its performance. The resonant coupling effect between two coils can be explained by using two identical objects. When the first object (as primary coil) vibrate at a certain frequency within close contact with the second object, then the second object (as secondary coil) resonates at the same frequency as the first. By using the resonant circuits, the process of wireless power transfer can be increased to centimeter distance.