Study of Axial Electromagnetic Force of Variable Flux Motor with Draw-Out Mechanism

Abstract

　With the recent trend toward electrification of automobiles, traction motors are also required to have a wide range operation and high efficiency. Currently, an interior permanent magnet synchronous motor (IPMSM) is mainly used. However, the improvement of the efficiency in the high-speed area is expected. Therefore, we have focused on a variable flux motor with a draw-out mechanism to achieve a high efficiency in high-speed areas. In our previous study, we proposed a structure that combines two rotors with different torque constants, and verified that the efficiency and variable flux characteristics can be improved. In this paper, we investigate the effect of the rotor structure on the axial electromagnetic force generated in the stator during a draw-out operation. This investigation indicated that the axial electromagnetic force is influenced by the draw-out rotor and the radial electromagnetic force during a draw-out operation.