Torque Improvement with Trapezoidal Magnet Rotor for V-Shaped Interior Permanent Magnet Motors

In this paper, a novel rotor structure is proposed for V-shaped interior permanent magnet (IPM) motors. By using V-shaped IPM motors, concentrated flux can be generated on the d-axis, resulting in a high torque density. However, there was a design issue, which was the leakage flux generated on the outer bridge. In the proposed motor, trapezoidal magnets are inserted into the rotor core instead of the conventional rectangular magnets. The width of the magnet is gradually narrowed in the radial direction so that the magnet can be supported by the rotor core without outer bridges. In this study, numerical verification was conducted to validate its effectiveness. From the numerical results, it was confirmed that the volume of magnets required to obtain the desired torque was reduced by 10.2% compared to conventional V-shaped IPM motors."