Prototype Experiments on a 1/32-Scale Model Via-Wheel Power Transfer Electric Vehicle

Abstract

SUMMARY Electric vehicles (EVs) are expected to play a leading role in the changeover from fossil fuels to clean energy. However, EVs are currently not very popular, owing to their short cruising distance and long charging time. Wireless power transfer from the infrastructure to running EVs is expected to be the solution to these problems. Electric vehicle and electrified roadway (EVER) has been proposed as a wireless power transfer system for EVs while in motion. Via-wheel power transfer (V-WPT) is expected to be a wireless power transfer scheme for EVER. We designed and prototyped a 1:32 scale model of a V-WPT system that consists of an RF inverter, an electrified roadway, a rectifier, and an EV with a dc motor. The output power of the prototype RF inverter was 5.9 W and the dc-RF conversion efficiency was 36.6%. The LC matching circuits for the V-WPT were designed with two-port conjugate matching because S11 of the V-WPT was intrinsically -0.06 dB. After matching, the S11 value was reduced to -21.5 dB. The power transmission efficiency of the V-WPT system was 75%. The RF-dc conversion efficiency of the rectifier was 62%. The total efficiency of the EVER system was 24.2%.