Microstructure design and analysis of rotor and stator in three-phase permanent magnet brushless direct current electric motor with low rare earth material

Abstract

Various hemicycle groove microstructures of surface permanent magnets and tooth surface stators are simulated to improve the motor performance by a finite-element analysis software in this study for designing, analysing and optimising and observation of the magnetic field strength distribution and to reduce the cogging torque in the permanent magnet brushless direct current motors. The output torque variation in the surface permanent magnet brushless direct current motor does not vary much or varies by a no more than 10% decrement in the situation of decreasing magnetic field strength while reducing the permanent magnet volume. The cogging torque of the optimal combination of the surface permanent magnet brushless direct current motor can be abated 62·4%, but the output torque is only decreased by 6·5% approximately because the usage amount of the rare earth permanent magnet volume in the designed surface permanent magnet brushless direct current motor is reduced by 5·3%. Finally, a prototype of the three-phase radial-flux surface permanent magnet brushless direct current motor with low rare earth material has been manufactured to verify the optimal simulation design.