Structural and Control System Design of a Homopolar Single-Stator Doubly Salient Permanent Magnet Motor

Electrified transport demands reliable and high-performance motor drives. Homopolar single-stator doubly salient permanent-magnet (DSPM) motors feature a simple rotor without windings or permanent magnets and stator-mounted excitation. However, during operation, problems such as large cogging torque, significant torque fluctuations, and disturbance to speed regulation performance are prone to occur. This study develops a three-phase homopolar single-stator DSPM motor with integrated Hall-effect rotor-position sensing. Sensing poles are machined directly into the shaft and maintain a fixed one-to-one circumferential correspondence with the rotor poles, avoiding the need for separate rotating sensing components. Four structural variables were optimized by three-dimensional finite-element analysis and a four-factor, four-level L16 orthogonal array. Absolute peak cogging torque decreased from 89.02 to 64.20 mN·m (27.88%), and the mean absolute value decreased from 23.83 to 13.56 mN·m (43.10%). An improved LADRC speed loop, using reconstructed observer error and continuous nonlinear feedback, was combined with FCS-MPCC. Simulated settling times for startup, speed-step, and 5 N·m load-step tests were 0.017, 0.012, and 0.006 s, with overshoots of 0%, 0%, and 0.43%. Prototype tests on a TMS320F28335 platform demonstrated no-load startup, speed tracking, and steady-state current regulation, whereas load-disturbance rejection remains to be experimentally validated.