Coupling Coefficient and Load Estimation for Wireless Power Transfer Systems with Transmitter Side Input Current

This paper proposes a novel coupling coefficient and load estimation method in wireless power transfer (WPT) systems. First, the relationship among the harmonics of the transmitter side input current, the coupling coefficient, and the load is mathematically derived in detail. Afterwards, a state estimation based parameter identification algorithm is utilized to accurately estimate the coupling coefficient and the load, with full consideration of information redundancy. Compared to the existing methods, the proposed method only requires transmitter side input current, can accurately estimate the coupling coefficient and the load at the same time, and can be applied to rather complex WPT topologies. Simulation and hardware experiments in an example LCC-C compensated WPT system verify the validity of the proposed coupling coefficient and load estimation method.