Non-linear Control Of Brushless DC Motor Based On Load Torque Observer

The traditional BLDCM adopts PID control and is driven by PWM square wave,which leads to the problems of slow speed response,large torque ripple and high noise.Meanwhile,the use of position sensor will make the structure of the motor more complex.Therefore,solving the above problems is of great significance for improving the performance of the BLDCM system.In this paper,Space Voltage Vector Pulse Width Modulation(SVPWM)is used to drive BLDCM,at the same time,the double sliding mode controller and load torque observer are designed to solve the problems of large torque ripple,slow speed response and weak anti-interference ability of the BLDCM.In order to solve the problem caused by the position sensor,the Kalman filter algorithm is used to study the sensorless control system of BLDCM.Firstly,the mathematical model is obtained according to the principle of BLDCM,and the SVPWM principle is introduced.The simulation model of BLDCM and its driving system is built by Matlab/Simulink according to the mathematical model and SVPWM principle.The simulation results verify that the BLDCM driven by SVPWM has good control effect.Secondly,the sliding mode control strategy are introduced in detail.On the premise of designing the BLDCM sliding mode controller and load torque observer,the simulation model of the BLDCM double closed-loop control system based on the sliding mode controller is established.Simulation results show that the BLDCM system has good performance under the load torque observer and sliding mode control.Compared with the traditional PID control scheme,this method has better operation effect,faster speed response,shorter time to reach the steady state,and better anti-load interference ability.In the last,the Kalman filter algorithm is introduced in detail,the simulation model of sensorless control system of BLDCM based on EKF is established combining the state equation.The simulation results show that the sensorless control system of BLDCM based on EKF is feasible.To sum up,in this paper,the control system of BLDCM is the research object,and realizes the speed control system of BLDCM by designing sliding mode controller,load torque observer and extended Kalman filter.The simulation results show that the designed in this paper improves the response speed and anti-interference ability of the BLDCM,and the sensorless control system based on EKF has better control effect.