Research And Implementation Of Sensorless Control Strategy For NC Machine Tools Permanent Magnet Synchronous Motor

The processing of precision components in intelligent manufacturing industry depends on advanced CNC(Computer Numerical Control)machine tools,and one of the core of CNC machine tools is servo system.At present,the research focus of high performance servo system is permanent magnet synchronous motor servo system.Therefore,this thesis takes CNC machine tool as the engineering research background,and permanent magnet synchronous motor as the specific research object.Through the mathematical model of permanent magnet synchronous motor,the vector control system is constructed.Through the research of speed loop control method,current loop control method and speed sensorless technology,the robustness of servo system and the precision of system control are improved.Firstly,the development status of control strategy and control method of servo system is introduced.Then,a suitable coordinate system is selected to establish a mathematical model of permanent magnet synchronous motor.Combined with voltage space transformation technology,vector control strategy,speed loop and current loop controller,a double closed-loop servo system model of permanent magnet synchronous motor is constructed.Secondly,the speed loop controller is designed,and the sliding mode variable structure algorithm is used to improve the system’s susceptibility to internal parameter perturbation.In order to improve the chattering problem of traditional sliding mode control,a dynamic sliding mode control algorithm with exponential reaching law and new switching function is introduced.In order to improve the anti-interference ability of dynamic sliding mode controller,a linear active disturbance rejection dynamic sliding mode coordination function control algorithm is designed.Thirdly,an adaptive sliding mode current loop controller is designed to further improve the performance of the system in adjusting time.At the same time,the unscented Kalman algorithm is designed to accurately track the sensorless rotor speed.Through Matlab/Simulink simulation,the stability and anti-interference of the control system and the effectiveness of sensorless technology are verified.Finally,the experiment platform of DSP controller is built,which includes hardware circuit and software design.It proves the effectiveness of the control strategy designed for permanent magnet synchronous motor.