Novel Salient Stator Pole-Shoe Structure for Reducing the Shaft Voltage of the PMSM

The permanent magnet synchronous motors (PMSMs) are exposed to harmful bearing currents and shaft voltage which affect their lifetime. This study suggests a novel salient stator pole-shoe structure (SSPS) to suppress the shaft voltage and bearing current. The SSPS interferes with the effect of the electric field between the coil and the rotor, thereby reducing winding-to-rotor capacitance C
wer
, which is a major factor for the shaft voltage. The electrostatic finite element analysis (FEA) is performed to calculate the parasitic capacitance and compare the difference between the SSPS and the classical pole shoe model. To validate the effectiveness of the SSPS, the magnetic field transient FEA is performed comparing with classical model. Finally, the shaft voltage of two prototypes (SSPS and classical model) is verified by experiment.