Studying the Influence of Parameters in a Lumped Tooth Force Based Noise Assessment of a Permanent Magnet Synchronous Machine

Kurzfassung

The generation of noise in permanent magnet synchronous machines (PMSMs) depends on the forces acting in the air gap resulting from the interaction between the magnetic flux density of the winding in the stator and the permanent magnets in the rotor. One approach to determine these forces is the Maxwell Stress Tensor (MST) method. It is used to obtain the force density in the air gap, which is then projected onto the stator teeth and the resulting forces are derived. Using the Lumped Tooth Force (LTF) method, these forces are integrated over a slot pitch and applied to the stator tooth at one or more points. In addition, the flux density, and therefore the force density, is calculated at defined radial positions in the air gap. In this work, the LTF method is used and the number of force points on the stator teeth is varied. The forces are then applied to the stator model within a finite element analysis (FEA) and the equivalent radiated power (ERP) is determined. By comparing these sound power levels, the sensitivity of the results to the number of force points and the selected radial positions in the air gap is analysed.