PMSM fed by 3-level NPC sinusoidal inverter with discrete state feedback controller

In this paper new discrete non-stationary linear-quadratic speed regulator for PMSM fed by 3-level NPC sinusoidal inverter is presented. Controlled sinus wave inverter with an output LC filter was used in order to reduce electromagnetic torque ripple of the motor. The novelty of the proposed control system consists in one state feedback controller using in order to control the angular velocity of the motor as well as to provide true sine wave of the motor voltages. It was found that some gains of the designed discrete controller are non-stationary and depends on the angular velocity of the motor. Use of non-stationary controller causes, that linearization and decoupling process of the motor with LC filter is not needed. Simulation test results of the designed control system are compared with results obtained for PMSM fed by classical 2-level inverter. Proposed control system can be used in industrial applications where torque ripple minimization is needed instead high dynamic performance.