Electromagnetic Field and Energy Flux in Wireless Power Transfer System

Wireless Power Transfer (WPT) is proposed as a power supply method for electric vehicles. WPT has been currently being commercialized in the 85 kHz band, although it is considered for use in the 13.56 MHz band (ISM band) and other high frequencies where couplers can be made more compact in the future. Since there is a possibility of unexpected energy transmission in the high-frequency band, it is necessary to design couplers that consider it. Therefore, in this study, we evaluated the relation between circuit elements such as inductors, capacitors, resistors, and the electromagnetic field in space from the energy perspective and also elucidated the energy transmission mechanism. In addition, the effectiveness of the method was demonstrated by adapting it to the Inductive Power Transfer.