Speed Response Analysis of Servo Motor and Control Strategy for Fast Transient Response

This paper presents an analysis of the speed transient performance of a servo motor, including their physical limit and a nominal speed response frequency. A new indicator of transient performance for servo drives is also introduced, which eis obtained from the measured speed response frequency using a proposed scaling method. This method reduces the dependency on changes in speed reference in case of step response analysis. The proposed transient performance indicator is the ratio of this scaled value to the nominal speed response frequency, which reflects how close the servo drive’s transient performance is to the limit transient performance of the servo motor. This paper also proposes the control strategy to fully utilize the physical limit of the speed transient performance. A strategy includes the predictive current control with finite-control-set to utilize the maximum output voltage, as well as a criterion for smooth transition of the current to the steady state. Additionally, the torque feedforward method is proposed to achieve the fast transient response of speed. The proposed control strategy is verified by experimental results and analyzed by the new transient performance indicator.