Design of robust optimal PI controller for PMSM servo drives

Abstract

Vector controlled PMSM servo drive is a MIMO full state feedback system. Since only the measurable quantities are used as the feedback to the controller. the whole problem is treated as a linear quadratic tracker (LQT) with output feedback for the purpose of designing the optimum controller to meet the given specifications. The performance of the optimal controller is evaluated by studying the transient and steady state response to step changes in reference speed. The sensitivity of each and speed loop controllers to changes in motor parameters and load torque are investigated. A torque ohserver is used for the feed forward torque control to mnke the optimal controller robust against load torque variations.