Implementation of Identical Spiral Square Inductive Coils for Wireless EV Battery Charging Application

In recent years, the popularity of wireless inductive power transfer (WIPT) system for electric vehicle battery charging (EVBC) is always ever-increasing. In the WIPT inductively coupled coil structure is the heart of the system and the mutual inductance (MI) between the coupled coils is the key factor for effective power transfer. This paper presents the analysis of mutual inductance between the spiral square coils based on the cross-sectional area ratio of spiral circular and spiral square coupled coils. The analytical computed MI values are compared with FEM (Ansys Maxwell) simulation and Experimental computed values. Finally, the designed spiral square coils are implemented in a laboratory prototype model and at the receiver side for effective electric vehicle (EV) battery charging a closed-loop PID controller is implemented for DC-DC buck converter. The effectiveness of the proposed controller has been tested by providing sudden changes in mutual coupling and change in reference value. The proposed system is suitable for both stationary and dynamic wireless EVBC.