Analysis of transmitter coil selection method for wireless power transfer system with multi-transmitter coils and one-receiver coil for high efficiency

Abstract

In a wireless power transfer system, if the receiver (RX) coil deviates from the transmitter (TX) area, the power transfer efficiency (PTE) drops rapidly. One of several method for solving the drawback is to expand the range of high PTE by arranging the multiple TX coils. If several TX coils are selectively activated according to the position and size of the RX coil, the power loss and leakage magnetic field generated in the TX coil having low influence can be reduced. However, research on the exact criteria for selecting an appropriate TX coil has not been conducted so far. Therefore, we proposed the TX coil selection criteria that can achieve the maximum PTE among several coils. Using the proposed criteria, it is possible to select the TX coils capable of maximizing PTE according to the position of the RX coil, and the proposed criteria can be applied to various cases regardless of the number and arrangement of activating TX coils. The criteria are derived through the mathematical analysis of the PTE according to the selection of the TX coil, and verified through simulation and experiment.