Research on Impedance Matching Method of Four-coil Wireless Power Transfer System

Abstract:
Compared with the traditional two-coil wireless power transfer (WPT) system, the resonant coil in the four-coil WPT system is not affected by the source and the load terminal to a large extent, and when the transmission distance (the distance between the receiving coil and the transmitting coil) is fixed, there is no need to change the original electrical parameters of the system. By flexibly adjusting the distance between the driving coil and the transmitting coil or the load coil and the receiving coil, the system power supply matching and impedance matching can be realized, so that the transmission efficiency of the system is always at a high level. Based on the four-coil wireless power transfer system, a novel adaptive impedance matching method of rotation angle is proposed in this paper. By constructing and designing the embedded receiving-load coil, the impedance matching of the system can be achieved flexibly by adjusting the angle. At the same time, based on the traditional PCB technology, the mutual inductance analytical calculation method under different angles is analyzed in detail. In addition, the simulation results agree well with the experimental results. By changing the angle between the receiving coil and the load coil, the maximum efficiency of the system can be improved by 10% compared with before optimization, which fully verifies the scientific property and practicability of the method.