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异步起动永磁同步电动机因其有较高的效率、功率因数和转矩密度而在高效节能场合的应用日益广泛,但由于其结构特点,在起动过程中定转子极数相同,会存在较大的发电制动转矩和脉动转矩,使得在起动过程中的最小转矩变小,严重影响电机的起动能力.该文基于一种新型6/8变极起动永磁同步电动机,实现起动时定子绕组6极、转子永磁体8极,以有效地削弱发电制动转矩和脉动转矩,提高起动能力;待一定时刻,定子绕组切换成8极完成牵入同步稳定运行.分别对该变极起动电机6极状态和8极状态下的电抗参数、磁场、转矩进行了分析及计算,得到6极起动情况下的各转矩分量-转速曲线,并与常规8极异步起动永磁同步电动机进行比较.结果表明,对于该变极起动电机6极起动过程中发电制动转矩和脉动转矩得到了有效地抑制,显著提高电机起动能力.最后,通过二维有限元模型仿真,以及对样机发电制动转矩的测量和空载起动实验,有效地验证了其正确性.“,”Line-start permanent magnet synchronous motors (LSPMSMs) have become widely applied in high efficiency and energy saving occasions for their high efficiency, power factor and torque density. But as the structural characteristics of that the motors have same pole numbers between stator winding and rotor permanent magnets (PMs), large braking torque and pulsating torque are exist which cause the minimum torque decreased and large fluctuation during starting process. The disadvantages have bad impact on motors' starting capability and in serious, the motors even cannot start-up. This paper presented a novel 6/8 pole changing LSPMSM to realize that stator winding are 6-pole, whereas rotor PMs are 8-pole at start-up so the braking torque and pulsating torque can get greatly decreased. And reach a certain state, stator winding change to 8-pole to pull into synchronization and stable running. The reactance parameters, magnetic fields and torques of the 6-pole state and 8-pole state of the proposed motor were analyzed and calculated, and the torque components-speed curves of conventional 8-pole LSPMSM and 6-pole state starting of the proposed motor were get in use of analytical method. The comparison results show that braking torque and pulsating torque get greatly decreased and the starting capability gets improved effectively. At last, the simulations in use of two-dimensional finite element method (FEM), the experimental measurements of braking torque of the prototype motor and the no-load starting experiment verify the validity of the design effectively.