Piecewise Stagger Poles With Continuous Skew Edge for Vibration Reduction in Surface-Mounted PM Synchronous Machines

The common method to mitigate the slot-frequency vibration and noise of the permanent magnet (PM) motors is skewing the stator slot or skewing the PM. However, the limitation of this method in pole-frequency vibration reduction exists. In this article, one method by adopting the piecewise stagger PM pole with a continuous skew edge is proposed to reduce the pole-frequency and slot-frequency vibration for surface-mounted permanent magnet (SPM) synchronous machines. First, the analysis of the radial force acting on the stator teeth is conducted. Basing on this, the limitation of the skewing slot method in reducing the vibration is revealed. In order to solve this problem, a piecewise stagger PM pole with a continuous skew edge for pole-frequency and slot- frequency vibration reduction is proposed and its principle of vibration reduction is presented in detail. The finite element models of three 6-pole/36-slot SPM motors are built to simulate the radial force. Finally, two 6-pole/36-slot SPM motors are manufactured and the experimental results validate the effectiveness of the proposed method.