Analysis and Design of Magnetic Cores for Rotary Wireless Power Transfer Applications

Power transfer in a wireless manner is a good solution in rotary applications for its high reliability and low maintenance. The magnetic design is a critical part of the system. This paper focuses on the modeling, analysis and design of different types of magnetic core sections from geometry, and discusses the factors that can improve the coupling coefficient. 3-D finite-elements method (FEM) is used to analysis the magnetic coupling characteristics of the system and rotation effects. For the same size of cores, the magnetizing inductance of U-shaped and E-shaped core are approximate, while the leakage inductance of E-shaped is almost 4 times the U-shaped. The structure with U-shaped cores has higher coupling coefficient and suffers from less rotation effects. However, E-shaped cores have lower electromagnetic radiations to surroundings. Finally, an experimental setup with U-shaped cores was designed and established. This paper provides the analysis and prejudgment for selection of cores of the magnetic system design.