A Study on Shaft Voltage of IPMSM Applying Tapering for Reducing Cogging Torque

To mitigate cogging torque, a primary source of vibration and noise in the interior permanent magnet synchronous motors (IPMSM), the method of tapering to the rotor or stator is widely adopted. However, in the case of IPMSM applying a tapering model, the distance between the rotor-stator and coil-rotor varies. These variations have a significantly impact on the parasitic capacitance, the main factor in shaft voltage. Therefore, in this paper, the parasitic capacitance and the shaft voltage are analyzed when the tapering is applied to the rotor and stator. The electrostatic finite element analysis (FEA) is performed to obtain the parasitic capacitance of the tapering models. Then, the shaft voltage is verified by comparing the three prototypes (basic model, rotor tapering model, and stator tapering model) through the experiment.