Analysis of the Radial Component of Electromagnetic Force Density and Vibration Behavior of an IPMSM With Multiple Three-Phase Winding Units

The unbalanced distribution of electromagnetic force density inside an electric machine's air gap is one of the leading causes of electromagnetic vibration along with associated noise. Many factors influence the unbalanced distribution of electromagnetic forces inside the machine air gap; however, this study focuses on the influence of armature reaction on the electromagnetic forces and the vibration and noise behaviour of an interior permanent magnet synchronous machine (IPMSM) having multiple three-phase sector winding units. Complete multi-physics model analysis is presented by investigating the distribution of the magnetic field density components generated due to the interactions between the magnetomotive force (MMF) generated by each independent three-phase winding unit, along with the radial force density components, and their impact on the overall vibration and noise of the prototype machine. Static 2-D Finite element analysis (FEA) using the frozen permeability technique with 2-D Fast Fourier Transform is used to analyze the magnetic flux density and the radial component of the electromagnetic force density distribution of the prototype machine under healthy and open-circuit fault conditions. Moreover, mechanical FEA is conducted using the multi-physics model technique to find the harmonic mode shapes of the prototype machine under different operating conditions to investigate the machine vibration behavior, which is finally verified by experimental tests. The findings of the high reliability systematic multi-physics analysis and the experimental results present useful information to understand the vibration behaviour of the prototype machine with multiple three-phase units.