Frequency Splitting Research of Series-Parallel Type Magnetic Coupling Resonant Wireless Power Transfer System

Frequency splitting has been widely observed in resonant wireless power transfer. However, there are some misunderstandings concerning this phenomenon in the series-parallel compensation structure. Based on the circuit theory, this paper adopts the mutual inductance model to analyze the relationship above load power, load resistance and the coupling coefficient in frequency splitting phenomenon, demonstrates that the splitting point is resonant point and split frequency solution of the equation is given. And then, the system quality factor of frequency split point is further defined, system impedance angle derived by inverter in the operative mode of the system frequency splitting is discussed, the limitations of suppressing measures of frequency splitting phenomenon is analyzed. Additional, the applicable range of suppressing measures is pointed out. Finally, the calculations and the experiments confirm these conclusions.