Composite Control Of Permanent Magnet Synchronous Motor Based On A New Sliding Mode Control Metho

Permanent magnet synchronous motor(PMSM)has been widely used in industrial fields due to high efficiency,high power density,and wide speed regulation range.In the vector control of PMSM,the proportional-integral(PI)method is used to design the controller.However,the requirements for PMSM control are getting higher and higher,and the PI control cannot meet the actual needs.In order to improve the control quality of the PMSM speed control system,a series of explorations and researches have been carried out around the new sliding mode control of the permanent magnet synchronous motor.Combined with backstepping control,model-free control,disturbance compensation technology,etc,the PMSM controller is designed.The main research contents of this paper are as follows:(1)Firstly,in order to improve the speed regulation performance of PMSM,a composite control method based on disturbance observer(DO)and fast non-singular terminal sliding mode control(FNTSMC)is proposed.The controller adopts the speedcurrent non-cascade control to replace the traditional double closed-loop control.Firstly,by introducing a fast non-singular terminal sliding mode surface,a sliding mode controller is designed to realize the fast-tracking control for PMSM.Then,in order to improve the anti-disturbance ability of the PMSM,a nonlinear disturbance observer(NDO)and a dual disturbance observer(DDO)are designed to estimate the disturbance during the motor operation,which are used for the feed-forward compensation control.Finally,the stability is proved based on Lyapunov stability theory.And the experiment further proves that the proposed method has the advantages of fast convergence and strong robustness against parameter variations and external disturbances.(2)The backstepping nonsingular terminal sliding mode control(BNTSMC)based on motor equivalent model and recursive principle is designed for PMSM,which ensure excellent tracking control.The benefits of this method are that the controller has asymptotic stability based on backstepping control design.Using sliding mode control has good dynamic response and anti-disturbance performance to matched disturbance.Then,a finite time disturbance observer(FTDO)is designed to improve the antidisturbance performance of the motor drive system for the mismatched disturbance such as external load torque.Finally,the effectiveness of the method is proved by experiments.(3)Finally,the above methods are all based on the motor mathematical model to design the controller,but it is difficult to obtain accurate motor parameters in the actual motor operation process.To solve this problem,a model-free integral sliding mode control(MFISMC)based on fast reaching law is designed.Firstly,according to the motor input and output variables,an ultra-local mode without the motor parameters is established.Then,an integral sliding mode controller with a fast reaching law is proposed to achieve fast convergence.The system disturbance compensation is realized by dual disturbance observer.Finally,the experimental results show that the proposed method has faster convergence speed and stronger anti-disturbance ability.