Analysis on the Spatial Impedance of the Wireless Power Transfer System in the Near Field

Abstract

In this paper, the spatial impedance of the wireless power transfer (WPT) system is analyzed, and a resistance tunnel is found. First, the definitions of the spatial impedance in the near field are discussed, and one definition is chosen. By using this definition, the concept of the resistance and the reactance are extended from a scaler form into a vector form. Under this definition and this concept, the spatial impedance is analyzed, and a resistance tunnel is found. The tunnel possesses an obvious direction which is from the receive coil to the transmit coil, and possesses a concave phenomenon on the resistance's magnitude curves. The reason for the forming of the tunnel is also analyzed by discussing the x-and z-components of the resistance. Second, the influences on the resistance tunnel by four factors are discussed. Only the current phase difference determines the existence of the resistance tunnel. The other factors only influence the magnitude and distribution of the resistance. The correctness of the theoretical calculation is verified by implementing an electromagnetic simulation via FEM. Since the WPT system is one of the typical coupling systems in the near field, one can infer that the resistance tunnel not only exists in the WPT system, but also exists in other coupling coil systems in the near field.

Research on Anti-offset Performance of the Wireless Power Transfer System with Asymmetric Coupling System

“…W ireless power transfer (WPT) is a new type of power transmission method in which the load and power supply are without contact, which has the advantages of safety, flexibility, and reliability compared with the traditional transmission methods [1][2][3][4][5][6]. WPT has a broad application in the fields of implantable medical devices [7,8], electric vehicles [9,10], etc.…”