Smooth speed control of motor drives with asymptotic disturbance compensation

For electrical drive speed control, this paper presents a scheme of jerk-constrained time-optimal control (JCTOC) that guarantees a minimum-time output response of the nominal drive under a magnitude constraint on machine jerk. By confining the machine jerk to the admissible range, smooth machine operations are achieved. Furthermore, the JCTOC is augmented with a novel disturbance observer (DOB) that ensures asymptotic rejection of an unknown disturbance with multiple frequency components. This is attained by incorporating a lowpass filter and several bandpass filters into the DOB structure, which is tuned based on the knowledge of the disturbance frequencies. The effectiveness of the proposed scheme is demonstrated through experimental studies of a permanent-magnet synchronous motor drive suffering from multiple-frequency disturbances.