内置式永磁同步电机不同转子拓扑结构的电磁性能及电磁振动噪声分析

Electromagnetic performance and electromagnetic vibration noise analysis of different rotor topologies of interior permanent magnet synchronous motor

为了研究转子拓扑结构对内置式永磁同步电机(IPMSM)电磁性能以及电磁振动噪声的影响,以8极48槽永磁同步电机为例,根据设计指标,分别建立单层和双层永磁体两种内置式转子的永磁同步电机有限元模型,两个模型在定子、绕组、永磁体用量及轴向长度上完全一致。首先,从磁路结构的角度分析交直轴电感的区别,并分别对电机的交直轴电感参数、转矩波动、空载反电势及其谐波含量和输出外特性进行有限元分析比较。其次,根据麦克斯韦张量法推导出径向电磁力密度的解析表达式,并分别将两台电机的气隙磁密和径向电磁力密度及经过傅里叶分解后的谐波含量进行分析比较。最后,建立电机的三维有限元模型,计算定子铁心和定子组件径向模态的振型及固有频率,并对两台电机的电磁振动噪声特性进行仿真分析比较。结果表明,对于内置式永磁同步电机,在永磁体用量相同的情况下,双层永磁体比单层永磁体的转子结构具有更加良好的电磁特性及电磁振动噪声表现。

To study the effect of rotor topology on the electromagnetic performance and electromagnetic vibration and noise of the interior permanent magnet synchronous motor(IPMSM), an IPMSM with 48 slots and 8 poles was modelled. Based on the design requirements, the finite-element models of the two IPMSMs with single-layer and double-layer permanent magnets were established. The two models were analyzed with the same stator, winding, amount of permanent magnet and axial length. Firstly, the difference of the d-axis and q-axis inductance was analyzed from the angle of the magnetic circuit structure, and the parameters of the d-axis and q-axis inductance, the torque ripple, the no-load back electromotive force, its harmonic content and the output characteristics of the motor were compared by the finite element analysis. Secondly, the analytical expression of radial electromagnetic force density was deduced based on maxwell tensor method, and the air-gap flux density, radial electromagnetic force density and the harmonic content after Fourier decomposition of the two motors were analyzed and compared. Finally, the 3D finite-element model of the motor was established, and the radial mode of vibration and natural frequency about stator core and stator assembly were calculated. Then the electromagnetic vibration noise characteristics of the two motors were simulated and compared. The results show that for the IPMSM, when the amount of permanent magnet is the same, the rotor structure of double-layer permanent magnet has better electromagnetic characteristics and electromagnetic vibration noise performance than that of single-layer permanent magnet.