Hybrid Method for Reducing Shaft Voltage Considering AC Copper Loss for IPMSM with Hairpin Winding

This paper presents a hybrid method that combines both analytical and finite-element methods to reduce shaft voltage (SV) considering AC copper loss. The proposed method consists of two stages. The first stage is a determination of design variables through the sensitivity analysis and the second one is an optimal design using a parasitic equivalent capacitance (PEC) and a finite-element method (FEM). To check the validity of the proposed method, it is applied to the design optimization of an interior permanent magnet synchronous motor. Also, the SV result gained by the PEC method is compared with that obtained by FEM.