Parameter Identification of a Six-Phase Permanent Magnet Synchronous Motor for Maximum Torque per Ampere Control

This paper proposes a parameter identification method for maximum torque per ampere (MTPA) control of an asymmetrical six-phase permanent magnet synchronous motor (PMSM) using a dual three-phase drive without additional motor-terminal voltage sensors. The proposed method measures the common-mode (CM) flux-linkage maps and identifies the CM dq-axis inductances and permanent-magnet flux linkage. For asymmetrical six-phase PMSMs, the CM subspace is equivalent to the fundamental torque-producing subspace in the vector space decomposition (VSD) model. An angle-scanning MTPA strategy is then implemented to determine the optimal current-vector angle. Finally, the identified parameters are validated through torque and power measurements obtained from dynamometer experiments. Experimental results demonstrate that the proposed method can accurately identify the MTPA operating point. The identified parameter model also provides accurate torque prediction, with an error of only 1% at the rated torque of 1363.5 N·m, while the measured torque at 600 rpm differs from the standstill value by only 19 N·m (1.4% of the rated torque).