Variable structure sliding mode based unknown input observer for speed identification of brushless DC motors

Abstract

A variable structure sliding mode unknown input observer (VSSM-UIO) is investigated to estimate the speed of permanent magnet brushless DC motor (BLDC) in this paper, which features in very good robustness to the parameters uncertainty and disturbance. Using the phase voltage mathematical model of BLDC, the observer is deduced by supposing back-EMF as an input disturbance, which has a good performance of speed and rotor position identification. By means of the designed Lyapunov function, the observer is proved to be stable in the infinite time and robust, even if the load torque disturbance, the parameter uncertainties exist. Simulation results show the validity of the proposed strategy.

Hybrid field oriented and direct torque control for sensorless BLDC motors used in aerial drones

“…This estimation technique is very important because the quality of the estimation directly impacts the performance of the overall control scheme. The majority of the previous techniques used sliding mode observers (SMOs) because they are robust to noise and parameter uncertainties [20][21][22][23][24][25][26][27][28]. Reduced order observers have been also used due to their computational efficiency and simpler structure [29].…”

“…The most popular estimation technique of the back‐EMF signals is theSMO technique because of its many advantages including good robustness to parameter uncertainty and variation, and low computational complexity, which in turn leads to fast convergence and dynamic response [26, 27]. The SMO technique uses currents and voltages expressed in the () frame.…”