Speed sensorless variable structure and event driven torque control of PMSM

In this paper the torque and speed sensorless permanent magnet synchronous motor (PMSM) control is presented. The main idea consists in merging the structures of the motor observer and the controller in such a way that electromotive force of machine determined in observer is used as a feedforward term in the controller. In addition the PMSM observer is using combination of the feedforward and feedback terms in order to enhance the sensitivity of the observer. Torque and flux control as well as the observer of PMSM are based on the sliding mode theory so guaranteeing high degree of robustness towards parameters variation and the external disturbances. Proposed control scheme is implemented on digital signal processor (DSP) system extended with field programmable gate array (FPGA) where event-driven current controlled modulator is realized. DSP serves for time discrete speed control and observer, while time critical current control is implemented on FPGA. Simulations and experimental results demonstrated high efficiency of the proposed estimation and control method