Continuously-Variable-Pole Induction Machine Drive for Electric Vehicles

This paper presents an operational methodology for continuous pole sharing in variable pole induction motors (VPIMs) to minimize machine and drive power loss. An optimization problem is formulated to determine torque sharing among poles, revealing that combining two-pole and six-pole components yields minimum losses and enhances magnetic material utilization for a typical machine, particularly at intermediate torquespeed operating points. A modulation method that incorporates common-mode voltage injection is introduced to maximize dc bus utilization. A proposed control architecture enables one pole to operate under vector control and the other under scalar control, thereby reducing parameter dependence for synchronization and reference generation. The proposed approach supports dynamic loss minimization using the dc bus current and by varying the scalar-controlled pole magnitude. Experimental results conducted on a toroidally wound 36-slot machine validate the effectiveness of the proposed approach.