Partial element equivalent circuit modeling and design for wireless power transfer system via magnetic resonant coupling

To study the characteristics of wireless power transfer (WPT) resonators via magnetic resonant coupling (MRC), distributed parameter models based on partial element equivalent circuit (PEEC) are built for MRC-WPT resonators and coupling link between two resonators, which is essential to design a MRC-WPT system. The track of one turn in WPT coil is modeled as a complete ring carrying constant current, and the parasitic parameters and high-frequency losses are considered in this modeling method. The circuit parameters of PEEC network are calculated by numerical integrals and analytical formulas. This modeling method can predict resonant frequency and power transfer capability for MRC-WPT system. Impedance and scattering parameter S-21 of circular spiral resonators are also calculated by method of moments (MoM), and the proposed modeling method shows good agreement with the simulated results and has high calculation efficiency. Two types of WPT resonators are designed in laboratory. Impedance and scattering parameter S21 are measured for each of the cases, and the results show that the PEEC modeling method has a better accuracy and can predict resonant frequency and power transfer capacity for MRC-WPT system.