Research of Optitmum Design of Surfaced-Mounted-PMSM by Finite Element Method

1. 2000年获得政府资助购买的微机，构建了考虑永磁电机内铁和永磁的非线性磁路的有限元分析系统，对永磁电机内涡流分布进行了详细的仿真。对于电动汽车的实际运行模式，即恒转矩运行和恒功率（弱磁场运行），电机中涡流的损失是定量明确的。另一方面，利用商业有限元软件对永磁电机的三维磁场进行了分析，明确了定子绕组的磁场分布，并通过转子永磁偏斜显示了制动力的减小。在钕铁硼等稀土磁体上涂覆Ni或Al，研究了涂覆Al和Ni的永磁有限元网格和Ni涂层的磁饱和度对永磁涡流的影响。得到了表面安装式永磁转子的可行设计方案。并对凸极式永磁电机进行了优化设计，确定其适合于无位置传感器电机。在上述设计理念的基础上，于2001年设计并制造了1.3 kW永磁试验电机。测试电机有8个极，转子由分段的pm组成。采用稀土磁体钕铁硼制备转子永磁材料，并涂覆Ni。目前设计的可行性已通过试验电机得到验证。

1. FEM Simulation of Surfaced-Mounted-PM SMPersonal computer was purchased by grant-in-aid in 2000, FEM analytical system taking into account of nonlinear magnetic circuit of iron and PM in PM motors was constructed, and then eddy currents distribution inside the surfaced-mounted-PM motor was simulated in detail. For real operation patterns of electric vehicles, which are the constant torque operation and the constant power (field weakening operation), the loss of eddy currents was clear quantitatively in the motor. In results the reduction of the loss was confirmed due to the insulated PM' s. On the other hand, the three dimensional magnetic field of PM motor was analyzed by commercial FEM soft, the magnetic field inendcoi1ofstatorwinding was made clear and the reduction of detent force was shown by the rotor PM skew.2. Establishment of optimum design for PM motorThe rare earth magnet such as NdFeB is coated with Ni or Al. An influence of Al- and Ni-coating FEM mesh of coated-PM and magnetic saturation of Ni-coatingon eddy currents in PM was investigated. In results, the available design of surfaced-mounted-PM rotor was obtained. Also the optimum design of salient type PM motor was investigated, and found suitable as a position-sensorless motor.3. Construction of the surface-mounted-PM motorOn the base of the above design concepts, 1.3 kW PM test motor was designed and constructed in 2001. The test motor has 8poles, and the rotor consists of segmented PMs. The PM of rotor was made from the rare-earth-magnet NdFeB and coated with Ni. Now the availability of design has been verifying by test motor.