The influence of magnetic properties of permanent magnet on the performance of IPMSM for automotive application

High power density is required for motors intended for automotive applications. Therefore, interior permanent magnet synchronous motors (IPMSMs) are commonly used in hybrid electric vehicles and electric vehicles. It is known that the characteristics of the magnetic materials are a significant factor with respect to the performance of the IPMSM, and the magnet is particularly important. In addition, currently, the high-performance magnets that have a high residual magnetic flux density are being developed, and technics for applying these magnets to motors are required. In this paper, three motors having different magnets with different residual magnetic flux densities are investigated for use in automotive applications. As a result, by using a strong magnet, the total torque and output power are increased, and the high-efficiency operating region is widened and shifted to the low-speed, high-torque range. Moreover, the maximum efficiencies at frequently used operating points are compared. In the city-driving, the efficiency is approximately the same. However, the efficiency in highway driving decreases when the strong magnet is used.