Contactless Magnetic Plug for Convenient EV Charging with Closed-Loop Control

This work aims to design and develop a contactless magnetic plug for convenient and safe charging of electric vehicle batteries. This is achieved by introducing an insulation gap in the high-frequency transformer located between the DC-AC and AC-DC power conversion stages. The gap in the transformer core and windings constitute a detachable plug that is contactless, electrically safe, very convenient, and eliminates any possibility of arcing and aging of contact. The design parameters of the magnetic plug are derived analytically and then verified using COMSOL. Two different closed-loop control techniques have been discussed to regulate the output voltage. A 5 kW 400V DC input and 96V DC output charging circuit are analyzed, designed, and simulated in PowerSIM. A scaled-down lab prototype of 1.0 kW is developed to convert power from 240V DC input to 60V DC output. The experimental results obtained from the lab prototype verify the proposed converter design. Several dynamic response results are also included to show the performance of the closed-loop system. The proposed design can be scaled up easily to higher power levels for fast charging.