In this study, a novel rotor structure for V-shaped interior permanent magnet (IPM) motors was proposed. V-shaped magnet arrangement enables the generation of concentrated magnetic flux on the d-axis, resulting in a high torque density. However, reducing the leakage flux generated in the outer bridge was an important design issue. In the proposed motor, trapezoidal magnets were inserted into the rotor core instead of conventional rectangular ones. By gradually narrowing the width of the magnets in the radial direction, the magnets can be supported by the rotor core without outer bridges. In this study, numerical verification was performed to verify its effectiveness. The numerical verification confirmed that the volume of magnets required to obtain the desired torque was reduced by 10.2% compared with that of conventional V-shaped IPM motors. In addition, a prototype was used to demonstrate the effectiveness of numerical verification. It was anticipated that the positional variation of the magnets in the rotor core would be a problem with this structure; however, during prototype production, it was demonstrated that this issue could be resolved by using a jig to fix the magnet position.
Minami et al. (2026) studied this question.