Electric Vehicles wireless charging system compensation based on the Magnetic Energy Recovery Switch

Abstract

A revised Electric Vehicle (EV) wireless charging system based on the Magnetic Energy Recovery Switch (MERS) is proposed in this paper. In order to achieve a better separation between the primary and secondary coils, bilateral compensated detachable transformer instead of the conventional coupling inductance is used in the system. It is clear that the mutual inductance of the detachable transformer is very sensitive to the relative position between the device on the EV and the device at the charging station, which causes some reactive power and harmonic currents. However, by the joint modulation of the frequency of the transmit circuit and the phase shifting angle of the introduced MERS circuit, the maximum efficiency can be maintained. The paper firstly describes the magnetic energy recovery switch circuit, and the mathematical model determines the magnetic energy recovery switch (MERS) circuit can be equivalent to a variable capacitor; Then puts forward the bilateral compensation strategy for the detachable transformer, in which the MERS circuits are introduced as the compensational capacitors, and mathematically proved the feasibility of the strategy; Next, by means of the above model, presents a method of PLL detection on the both sides of the phase errors between the voltages and the corresponding currents, to determine the magnitude of the phase shifting angles of the MERS circuits and the frequency of the inverter circuit; Finally, the proposed idea is validated by simulation results.