Research About Fixed-time Control Of PMSM

Permanent magnet synchronous motor(PMSM)has been widely recognized in various fields of industrial production and control because of its advantages of high power density,high stability,relatively simpler physical structure and relatively smaller floor space.However,PMSM system is a multivariable and strongly coupled nonlinear system,so it's difficult to guarantee the control performance of PMSM in actual industrial production because of the change of system parameters due to external disturbance such as temperature.Only when a robust and fast response control law is designed for PMSM mathematical model,the stability and fast response ability of PMSM drive system can be guaranteed.Firstly,this paper introduces the mathematical model of PMSM in different coordinate systems,and the conversion principles between them are analyzed.Then,the finite time control theory is introduced in detail,including its definition,forms,advantages and disadvantages.In addition,a detailed and systematic construction method for the finite time control of PMSM is given by using the backstepping method.Moreover,the advantages and disadvantages of PMSM using different vector control are introduced in detail,and the expected value of stator currents under different vector control is deduced.Secondly,the mathematical model of PMSM is de dimensionalized and reconstructed.At this time,for driving PMSM and response PMSM with different initial conditions,the stability function is constructed based on nonsingular fast terminal sliding mode control and Lyapunov stability theory.Then the adaptive fixed time controller required for error system and the fixed time adaptive laws of system uncertain parameters are derived.Finally,the fixed-time synchronization of two PMSMs is realized.In view of the theories above,the speed of PMSM is regulated.On the basis of sliding mode control,a nonsingular fast terminal sliding mode-fixed time load torque observer is constructed.For the dual anti-interference of nonsingular fast terminal sliding mode control and fixed time control,the stability of motor against load disturbance is guaranteed.At the same time,the chattering problem of sliding mode control is effectively weakened or even removed.In addition,the stator resistance R which is the internal system parameter of the motor also has obvious uncertainty,so the stator resistance is identified and compensated on-line adaptively to ensure that the PMSM system is not affected by the fluctuation of the stator resistance;finally,the backstepping integration fixed time control is adopted for the PMSM,and the finite time stability of PMSM is realized based on the Lyapunov stability theory.In the end,the control scheme is verified by Matlab.The simulation results show that the adaptive fixed time synchronization scheme proposed for PMSM with different initial conditions and the fixed time control strategy designed for PMSM speed control have obvious advantages,such as fast convergence speed,strong robustness and high control accuracy.The thesis has 28 figures,and 73 references.