Research On AC Servo System Of Permanent Magnet Synchronous Motor Based On ADRC

Permanent magnet synchronous motor(PMSM)is characterized by small size,high efficiency and low noise,and is widely used in aerospace,robot control and numerical control system.As the actuator of the servo system,PMSM servo system in the industrial field needs a real-time disturbance suppression control algorithm under the action of model parameter changes,load changes and inertia changes.ADRC technology is a new control technology that can replace PID in industry,with the characteristics of fast response speed,high control accuracy,strong anti-disturbance ability,and does not depend on the model characteristics.In this paper,ADRC is applied to the permanent magnet synchronous motor servo system,which can effectively improve the system’s anti-disturbance ability and control accuracy.(1)First,the mathematical model of permanent magnet synchronous motor is analyzed,and the state equation under rotating coordinate system is obtained by means of coordinate transformation.The motor mathematics of PMSM is decoupled by vector control with _di(28)0.In this paper,the design steps of ADRC for velocity loop and current loop are introduced.ADRC theory can be used to eliminate the disturbance caused by load disturbance and friction coefficient term in velocity loop.(2)In the analysis of SVPWM algorithm,the dead zone effect on the current loop is considered,the voltage error caused by the effect is compensated,and the current harmonic is eliminated.Finally,under the condition that the position loop is still PID,the PID controller of the velocity loop and the current loop is replaced by the first-order LADRC to complete the three-loop control.The system simulation model was established under Matlab/Simulink,and the superiority of LADRC in servo system can be seen through the comparison of PID and LADRC.(3)In terms of hardware structure,DSP28335 is the control core,and the controlled object is the 750W surface permanent magnet synchronous motor.Rectifier circuit,filter circuit,inverter circuit,as well as bus voltage,current and speed detection circuit are designed.The DSP peripheral function is configured on the software program,the control algorithm is written,and the simulation results are verified by experiments.