State and Parameter Estimation of Brushless DC Motor Based on H∞ Filter
The back electromotive force(EMF)is an essential parameter in the speed control of brushless DC motor.The pa-per presents a method of back EMF estimation based on extended H∞filter which the statistical characteristics of noise are unknown,by establishing an augmented model under the stationary coordinate system of two-phase stator,the back EMF,the stator current,inductance and resistance as the state vector.A Lyapunov function of the state error and Jacobian matrices of nonlinear function is constructed,and a full-rank matrix is designed to index the change of the Jacobian matrices.Based on the boundedness of the ran-dom process,sufficient conditions for the estimated error of the algorithm are given.The simulation results show that,the extended H∞ filter can always have good convergence speed and high precision of parameters estimation whenever the motor is running at a constant or accelerated speed,which can realize the precise control of the motor.
brushless DC motorstate and parameter estimationextended H∞filterconvergence analysis