Accurate Modeling, Design, and Load Estimation of LCC-S Based WPT System With a Wide Range of Load

Modeling of the wireless power transfer (WPT) system is the premise to design and control it. First harmonic analysis (FHA) is a simple and effective method to model theWPT system, but its accuracy may decrease with the variation of load in a wide range. In this article, harmonics are analyzed in the primary side of an LCC-S compensation network based WPT system, depicting a waveform of the output current of the inverter much closer to the real one compared with FHA-based model. In the secondary side, the time-domain analysis is conducted both in continuous conduction mode and discontinuous conduction mode of the rectifier, deriving an equivalent input impedance featuring the nonlinear characteristics of the system. Based on the proposed model, the parameters of the LCC network are designed, proving to tune the ZVS condition better than the FHA-based method. Finally, the load of the system is estimated, achieving a high accuracy (with the estimating error less than 5%) in a wide range with a simple sampling method.