ROBUST CONTROL OF LOW-COST DIRECT DRIVES BASED ON INTERIOR PERMANENT MAGNET SYNCHRONOUS MOTORS

Torque ripple compensation problem is considered for electrical drives, based on low-cost direct drive interior perma-nent magnet synchronous motors. Robustness properties of the speed and position control systems have been studied using time scale separation properties of the current, speed and position control loops. It is shown that system closed-loop dynamics according to new controller design has cascaded properties with speed and position control loops con-nected in series and therefore has potential of high frequency torque ripple compensation by increasing controllers gains. Experimental results are presented for two motors with similar rated data but significantly different level of the torque ripple. It is shown that despite of significand difference in parasitic torque amplitude, the similar position con-trol performance can be achieved. It makes proposed control algorithms suitable for both high dynamic performance and low-cost direct drive applications with medium performance requirements. References 13, figures 7.