Analysis for Axial Force of Slotted-Type Axial-Flux Magnetic Coupler

The mechanical properties have an important effect on the stability and optimization of magnetic coupler. Therefore, axial force as part of mechanical properties is necessary to be explored in-depth. In order to calculate the axial force of slotted-type axial-flux magnetic coupler (SAM C), the magnetic flux density is derived by using the equivalent magnetic circuit method. Based on that, the formulas for the axial force are obtained by utilizing the equivalent magnetic charge method. The axial forces under different angular displacements are analyzed by using the discrimination method, then the influence of number of poles and air-gap lengths on the maximum axial force are studied. The results derived from analytical model are compared with those obtained from finite elements simulations. Calculations and simulations show that the maximum axial force appears at angular displacement is 0°, and the maximum value rises sharply when the air-gap length is below 3 mm. As the number of poles increases, the maximum axial force decreases gradually.