Speed ??control Of Brushless DC Motor Based On Internal Model Principle

Brushless DC(BLDC)motor has been widely used in agriculture,aerospace and industry for its simple structure,high efficiency and reliability.With the deepening of people's un-derstanding of modern control theory,there are higher requirements for the performance and control accuracy of brushless DC motor.Therefore,it is of great significance to study how to improve the response speed and control accuracy of BLDC motor control system.In practi-cal application,BLDC motor is easily affected by the uncertainties of motor parameters and external disturbances.So how to design effective control methods to improve the control per-formance of BLDC motor has become an important research direction.In this paper,BLDC motor is taken as the research object.Based on the internal model principle,the problems of high precision speed tracking and robust tracking of BLDC motor under uncertain motor pa-rameters are studied under the framework of output regulation theory.Specific research work is as follows:First,the structure characteristics and practical operation principle of BLDC motor are analyzed in detail.Based on this,the mathematical model of BLDC motor can be established later.Then,the mathematical model of BLDC motor is established,and the speed control prob-lem of BLDC motor is described and analyzed.A static state feedback controller is designed without considering the uncertainties of motor parameters.In order to make the state matrix of the closed-loop system exponentially stable,the feedback gain calculation should be completed first,and then the feed-forward gain calculation should be completed.However,in practical en-gineering,the state variables of the system may not be easily obtained directly.In view of this situation,a dynamic output feedback controller is proposed,which mainly includes the design of an observer and a stabilization control law.Next,the problem of robust speed control for BLDC motor is studied.By establishing the mathematical model of BLDC motor with parameter perturbation,the speed control and load disturbance rejection of BLDC motor are transformed into a robust output regulation problem.According to the internal model principle,a dynamic state feedback controller is designed when the frequency information of the external system is known.The controller does not depend on the solution of the regulator equation.It mainly includes a compensator and a state feedback control law.Furthermore,when the state variables of the system are unmeasurable,a dynamic output feedback controller is designed based on the dynamic state feedback controller,and an observer is constructed to observe the states of the system.Finally,the effectiveness of the designed controllers is verified by simulation in MATLAB.