Torque control of a brushless DC motor using multivariable sliding mode extremum seeking PI tuning

Abstract

In this paper, a novel Multivariable Sliding-mode Extremum Seeking (MSES) Proportional-Integral (PI) tuning method is proposed and its application is studied for torque control in a Permanent Magnet Synchronous Motor (PMSM). To this end, the stator three-phase currents are characterized by their maximum amplitude which directly controls the shaft torque. Hence, a PI controller is applied for controlling the maximum amplitude of the stator three phase currents. Due to requiring only one control loop to control the stator phase currents, the computational and implemental costs of the system reduce significantly when compared with conventional current controllers. Here, multivariable sliding-mode extremum seeking method is proposed as an optimization technique to tune parameters of the PI controller. This makes the PI current controller more efficient in terms of disturbance rejection and transient conditions. Furthermore, rotor position detection is conducted by applying Hall Effect sensors and using a continuous estimation method. This affects the switching sequence of a three-phase inverter connected to PMSM. The simulation results demonstrate the advantages of the proposed controller in terms of fast and precise convergence and robust performance in face of disturbances and uncertainties.