Simultaneous two-axis position estimation of receiver coil using different radii of transmitter coils in WPT

Wireless power transmission (WPT) is a major technology and is mainly used in transmitting power to small electronic devices. WPT is also expected to be used for larger, higher-power devices such as EVs. One of the problems with the use of WPT is the loss of efficiency due to the misalignment of the transmitter and receiver coils. Previous studies focus on circuital methods to prevent efficiency loss such as impedance matching or frequency tuning. However, these methods do not solve the coil misalignment itself. The purpose of this paper is to propose a two-axis position estimation method in order to eliminate the misalignment. The two axes mean the parallel and vertical directions of the coils. Knowing coil position information in two axes will contribute significantly to position adjustment between coils, compared to the case of only one axis position information. This paper also verified the accuracy of the proposed method experimentally.