Research On PMSM Control Strategy Based On Deadbeat Current Prediction

Permanent magnet synchronous motor(PMSM)is superior to other types of motor because of its small size,light weight,high power density and simple control structure.The traditional three-PI control has shown better control performance in PMSM control system,and has been widely used in servo control motor and other fields.At present,PMSM is gradually applied to the servo control field of new energy vehicles with its excellent structure and easy control characteristics,so higher requirements are put forward for its control accuracy,dynamic response and robustness.Aiming at the problem of low control accuracy of previous control strategies,this paper takes tabulated PMSM as the research object,deeply analyzes the defects of speed response and current static difference in triple PI control algorithm,and by introducing a new control algorithm,completes the research of optimal control strategy of PMSM.The main work done is as follows:First,by studying the basic structure and working principle of PMSM,the mathematical model of PMSM is established,and the coordinates are transformed to the two-phase stationary coordinate system and the synchronous rotating coordinate system.Space vector pulse width modulation(SVPWM)is briefly introduced,and the simulation model of traditional control system is built and analyzed under MATLAB/Simulink combined with triple PI control.Second,aiming at the low control efficiency of PI speed loop,the sliding mode variable structure control strategy is introduced.Aiming at the problems of sliding mode chatter-out,large overshoot,poor anti-disturbance ability and so on when the traditional sliding mode control algorithm is used in permanent magnet synchronous motor,a new sliding mode variable structure control strategy with mixed reaching rate is proposed.Firstly,in order to reduce the overshoot phenomenon of no-load start and speed up the approach speed,a logarithmic function of rotational speed error was introduced into the isokinetic term of the traditional exponential approach rate.Secondly,a smoother hyperbolic tangent function was used to replace the sign function,which effectively suppressed the chattering of the system,and Lyapunov function was used to verify the stability of the new approach rate.Finally,it is introduced into the control of permanent magnet synchronous motor,and a new controller is designed.Third,aiming at the problems of complex parameter setting and large static current difference in the current loop,the deadbeat predictive current control algorithm is firstly introduced into the motor control system,which successfully replaces the double PI current control loop and produces more superior control performance.However,the predictive control algorithm is easy to be affected by the motor parameter mismatch.A sliding mode disturbance observer based on log reaching rate is designed to compensate the disturbance collected to the voltage link,which reduces the static current error caused by the parameter mismatch and effectively improves the robustness of the motor control system.Lastly,a system simulation platform through MATLAB/Simulink is built to verify the feasibility of the scheme from the theoretical perspective,and a DSP experiment platform is built to verify the superiority of the control algorithm from the experimental perspective.Figure [48] Table [4] reference [70]...