Design of IPMSM Considering Shaft Voltage and AC Copper Loss for EV Propulsion with Wide Operating Range

This study investigates the interrelationship between shaft voltage (SV) and AC copper loss (ACCL) based on design variables that influence both characteristics. In previous works, issues with SV and ACCL have been reported in electric vehicle propulsion motors operating at high speeds. While methods to individually reduce these characteristics are well established, the correlation between them with respect to design variables has not yet been explored. To analyze this correlation, an analysis of the equations related to parasitic capacitances and ACCL is conducted to identify the key design variables affecting both SV and ACCL. These variables include the distance between the winding and the rotor, slot opening width, and winding width. Based on these design variables, a correlation analysis is conducted to confirm how these characteristics change simultaneously, and the results are verified through finite element analysis. Finally, an optimization process is implemented to minimize SV and ACCL while achieving the target average torque. The results are validated experimentally.