Research On Control Strategy Of Permanent Magnet Synchronous Motor Based On Sliding Mode Algorith

Permanent magnet synchronous motors are widely used in industrial production,aerospace,new energy vehicles and other fields,and have the advantages of high efficiency,stable operation,low loss,low environmental pollution,small size and flexibility.In view of the growing demand for high control performance,the traditional control needs to be further improved,so it is significant to study the control strategy of permanent magnet synchronous motor.With the unique advantages of strong anti-interference capability and good robustness,the sliding-mode algorithm is introduced into the control system of permanent magnet synchronous motor.The main research work of this thesis includes:1.Analyzing the key link coordinate transformation and Space Vector Pulse Width Modulation(SVPWM)technique in vector control.Introduce three coordinate systems and establish the mathematical model of permanent magnet synchronous motor under three coordinate systems.Focus on the analysis and design of PI speed controller module,PI current controller module and SVPWM module in the vector control system of the permanent magnet synchronous motor under the traditional dual PI controller,and construct the corresponding simulation model in the simulation platform MATLAB/Simulink,and finally construct the simulation model of the overall vector control system to verify the feasibility and correctness of this control strategy.2.In order to solve the problems of overshoot and insufficient anti-interference ability of traditional PI speed controller,the integral sliding mode speed controller is designed.To further suppress the jitter phenomenon,a new sliding-mode speed controller based on the integral sliding-mode speed controller is designed based on a new convergence law,and the amount of system state variable correlation is introduced in the convergence law to make the new convergence law adapt to the change of the sliding-mode surface and the system state.By comparing the designed integral sliding mode speed controller,the new sliding mode speed controller and the traditional PI speed controller in the simulation platform,the problems of the traditional PI controller in terms of speed overshoot and insufficient anti-interference ability are verified,and the proposed controller can solve this problem well.3.Sliding mode algorithm is used as the basis to study the control without position sensor.Based on the traditional Sliding Mode Observer(SMO),a super-twisting sliding mode observer combining the super-twisting algorithm and the sliding mode algorithm is proposed to further reduce the jitter problem of the control system for the high performance requirements of the position sensor-less control system of the permanent magnet synchronous motor.Simulation results show that the proposed control method can provide accurate observation of rotor position and speed under the conditions of motor start with load,sudden speed change and sudden load change,which can overcome the speed overshoot problem and also provide effective suppression of torque,three-phase current pulsation and the inherent vibration of the sliding mode with good anti-interference capability and robustness.Through the analysis of simulation and hardware platform test results,this research work proves that the proposed control strategy is feasible,expands the application scope of permanent magnet synchronous motor,improves the control performance of permanent magnet synchronous motor control system,and can provide reference and reference role for the same type of motor controller and position sensorless control research.