Wireless power transfer for deep cycle lithium-ion batteries in electric vehicles using inductive coupling

Abstract

This study presents designing and evaluating a reliable wireless power transfer (WPT) mechanism to charge electric vehicle (EV) batteries using resonant coupling. The EV wireless system was created applying the principles of mutual inductance whereby the receiving and transmitting coils were interlinked and connected to their circuits. Significant mathematical work was also done to obtain the equations for the impedance, the power input, and output power. Proteus software was employed to draw a Printed Circuit Board (PCB) for the reception of the receiver and the transmitter circuits. The simulations were conducted using ANSYS Maxwell and MATLAB softwares, utilizing the key parameters of the transmitter and the receiver coils. The experimental setup included an EV installed with transmitter and receiver circuits, copper coils, a compensation network of capacitors, and a 12 V battery voltage monitor. The study showed that the efficiency of wireless power transfer was 78% with the enhanced power density for the gap ranging between 6 and 20 cm. The innovations presented in this paper are a new lower operating frequency of 70 kHz, coil optimization, and a dynamic study on coil misalignment all of which enhance the efficiency and reduce cost of the proposed system.