充磁方式对永磁无刷直流电机激振力波的影响

Influences of Magnetizing Modes on Exciting Force Waves of Permanent Magnet Brushless DC Motor

为降低水下航行器用永磁无刷直流电机(PM BLDCM)的振动与噪声影响,针对PM BLDCM在不同充磁方式下电磁激振力波存在差别的问题,建立了PM BLDCM的有限元分析模型,分别在空载和负载条件下,对比分析了径向和平行2种充磁方式下气隙磁密的分布特点。基于Maxwell应力张量法计算电磁力,完成了空载和负载条件下电机径向电磁激振力波的仿真,对比了2种充磁方式对径向电磁力波的影响,得到了其分布特点。研究结果表明,空载和负载条件下,电磁激振力波存在较大差异,为确定充磁方式对电磁激振力波的影响,需要在负载情况下完成分析;与平行充磁相比较,负载时径向充磁方式下,主要频率的幅值均有所增大,而其余频率的幅值有所降低。

In order to reduce the vibration and noise of the permanent magnet brushless DC motor（PM BLDCM） for underwater vehicle, a finite element analysis model is established for PM BLDCM to investigate the difference between an electromagnetic exciting force waves of PM BLDCM with two different magnetizing modes. And the distribution characteristics of flux density of air gap for parallel and radially magnetizing modes in both no-load and load conditions are obtained and compared. Then, the electromagnetic forces are derived via the Maxwell stress tensor,and the electro- magnetic force waves of PM BLDCM in both no-load and load conditions are simulated. The influences of two magnetizing modes on electromagnetic force waves are analyzed, and the distribution characteristics of the waves are achieved. The results show that in no-load and load conditions the electromagnetic exciting force waves are quite different, so the influence of load on exciting force waves must be considered in analyzing the influence of magnetizing mode on the exciting force waves; and compared with in parallel magnetizing mode, the amplitude of the main frequency increases in radially magnetizing mode but the amplitudes of other frequencies reduce.