LAUSR

In inverter-fed electrical machines, the sideband current harmonics around the switching frequency introduce annoying vibration and noise that are difficult to predict by finite element method (FEM) due to their high frequency. This article proposes a semi-analytical method to calculate the high frequency electromagnetic force and vibration of permanent magnet synchronous machines (PMSMs), with particular attention to the sideband harmonics caused by the inverter. Based on the analytical expressions of electromagnetic force induced by current harmonics, an efficient field reconstruction (FR) technique that is the combination of an analytical approach and FEM is proposed. A case study for this technique is conducted on PMSMs, which shows that the simulation time is reduced to approximately a few hundredths of that of the FEM. This technique is followed by a mode superposition method for high frequency vibration prediction. An experiment is also performed. The results show that the proposed technique is very precise on the basis of high efficiency.