Multi-band coil design for wireless power transfer at 85 kHz and 6.78 MHz using high order resonant frequency of short end coil

摘要

Wireless power transfer is a popular research topic in recent years. Allowed frequencies for wireless power transfer (WPT) are limited by the industrial, scientific, and medical (ISM) radio bands and each country's law. Different applications of wireless power transfer need to use different frequency bands. A single transmitter coil which can adapt to multiple frequency bands is needed to reduce the number of transmitter coils. In this paper, transmitter coil design for two frequencies using high order resonant frequency of short end coil is proposed. First resonant frequency is allocated at 85 kHz for Electric Vehicles by using capacitor. Second resonant frequency is allocated at 6.78 MHz (ISM band) by designing the coil shape. Characteristics of a prototype coil is described and the feasibility is confirmed by experiment.