Robust measurement disturbance observer design for AC motor drive systems with current measurement errors

In the vector control, current measurement errors deteriorate the motor drive system since the vector control is based on the current control. In this paper, in order to obtain precise torque control and eliminate the speed ripple, an online measurement disturbance observer (MDO) is proposed. Based on parameter sensitivity analysis, a practical method of designing robust MDO gains is proposed. The proposed method is applied to a commercial 1.1-kW permanent magnet synchronous motor to show its effectiveness and applicability.