Improvement in the Transmission Efficiency of EV Wireless Power Transfer System Using a Magnetoplated Aluminum Pipe

The wireless power transfer (WPT) system in an electric vehicle charger uses a litz copper wire (LCW) in the transmission coil to reduce the high-frequency loss at 81-90 kHz. The litz wire improves the performance of the WPT system by increasing the number of strand wires and reducing the diameter while simultaneously increasing the cost. Using a solid wire coil reduces cost, but it causes a high frequency loss that reduces the efficiency. Therefore, this paper proposes the use of a magnetoplated aluminum pipe (MAP) in a transmission coil. Compared to the solid wire, the MAP is light and cheap to manufacture. In our prototype, the transmission efficiencies between coils were 95.67%, 94%, and 92.6% for the LCW, MAP, and aluminum pipe coils, respectively. Therefore, the MAP coil can effectively be used as a replacement for the LCW coil in the transmission coil.