Design And Analysis Of Permanent Magnet Motor

Compared with electrical excitation motor, permanent magnet (PM) motor has great advantages, such as simple structure, high efficiency, small volume, reliable operation, and etc, which is widely applied in aerospace, national defense, agriculture, industry, and our daily life. Motors with Nd-Fe-B materials are proposed to replace original electrical equipments because of the high efficiency and the low energy consumption. Designers are faced with the high challenge to design and optimize the motor.Firstly, the structure and operation principle of the PM Brushless DC motor (BLDCM) are analyzed in this paper. Based on the equivalent magnetic circuit method, a preliminary design program is presented for a BLDCM. With the electromagnetic FEM software, the original model is built and its parameters are verified.Secondly, an optimization analysis of the motor is fulfilled. The contrasts are performed in different tooth width of the stator and different rotor types. Larger tooth width of the stator can reduce the magnetic saturation level. Four types of rotor structures are compared. The influences of PM shapes and rotor types on motor performances are analyzed among surface-mounted and internal BLDCMs.Finally, with the electromagnetic FEM software, magnetic field and the characteristic curves are simulated in2D field and3D field in both steady and transient state of the motor. The distribution of the magnetic field around the motor’s edge is analyzed and the torque ripple is studied in detail under current commutation. Load test results on the prototype prove that the design of PMBLDCM meets the demands.