Simultaneous estimation of two parameters based on secondary-side information for wireless power transfer via magnetic resonance coupling

A dynamic wireless power transfer system is expected to extend the limited driving distance of electric vehicles. Because the transmitting efficiency changes according to the vehicle motion with dynamic charging, developing a control strategy for maximizing the efficiency is one of the most important issues. Previous research has proposed secondary-side control based on estimating the coupling coefficient between a transmitter and receiver to simplify the ground facilities, which would be applied to rugged roadways over long distances. However, the primary voltage and internal resistance of the transmitter have to be strictly designed to achieve maximum efficiency control on the secondary side. In order to ease these restrictions, this paper proposes a multi-parameter estimation method based on secondary-side information. Simultaneous estimation of the primary voltage and mutual inductance mitigates voltage control on the primary side and ensures compatibility with different systems. Simultaneous estimation of the transmitter resistance and mutual inductance tolerates a variety of transmitter specifications. The effectiveness of the proposed method and its applicability to secondary-side control were demonstrated in simulations and experiments.