负载特性对不均匀气隙结构异步起动永磁同步电机退磁的影响

Influence of Load Characteristics on the Demagnetization of LSPMSM with Non-Uniform Air Gap Structure

不均匀气隙结构的异步起动永磁体同步电机是针对普通异步起动永磁川步电机由于气隙磁场谐波复杂而导致的运行过程中转矩脉动大、电磁噪声高等问题提出的，此结构电机的永磁体退磁情况与普通电机有较大不同。本文基于永磁体内各处的磁场矢量基本相同的原则，利用永磁体内部一点的磁密表征整个永磁体在运行过程中磁密的变化，对不均匀气隙结构异步起动永磁体同步电机永磁体工作点展开了理论研究与有限元仿真。分析了影响电机退磁的因素，研究了施加不同负载与转动惯量时永脱体的磁密变化情况，得到电机稳态运行时和起动过程中永磁体工作点的变化规律，提出了获得永磁体磁密最小工作点的研究方法。

Line-start permanent magnet synchronous motor （LSPMSM） with non- uniform air gap structure is proposed for reducing torque ripple, high electromagnetic noise caused by the complex harmonic distortion rate of air gap magnetic field of common LSPMSM. The demagnetization condition of the permanent magnet of the structure is different from that of the ordinary motor. In this paper, based on the principle that magnetic field vector in permanent magnet is almost the same, the magnetic flux density of the permanent magnet is characterized by the magnetic density of inner point of the magnet. Theoretical study and finite element simulation of line-start permanent magnet synchronous motor with non-uniform air gap structure are carried out. This article has analyzed the influence factors of the motor demagnetization, and relationship between load characteristic and demagnetization of permanent magnet has also been studied. In this paper, the variation law of permanent magnet working point during steady state operation and starting process is obtained, and research method of obtaining the minimum working point of permanent magnet is proposed.