Development of Digital Control for High Power Permanent-Magnet Synchronous Motor Drives

This paper is concerned with the development of digital control system for high power permanent-magnet synchronous motor (PMSM) to yield good speed regulation, low current harmonic and stable output speed. The design of controller is conducted by digitizing the mathematical model of PMSM using impulse invariance technique. The regulation and limitation of control parameters are also studied. In addition, a predicted current estimator, which is insensitive to motor feedback currents, is proposed to function under stationary frame for harmonic current suppression. A digital control system for 75kW PMSM is realized with digital signal processor (R5F5630EDDFP). Experimental results indicate that the total harmonic distortion of current is reduced from 4.1% to 2.8% for 50kW output power by the proposed predicted current estimator technique.