Design And Optimization Of Permanent Magnet Synchronous Motor Servo System

The servo system is a feedback control system used to accurately follow a process.It is widely used in high-end fields such as CNC machine tools,aerospace,and robot control.The typical servo control system consists of a driver and a motor.AC permanent magnet synchronous motor(PMSM)has become the main executive component of the servo system due to its advantages in control performance.The field weakening algorithm is a common method to improve the performance of the servo system;the sensorless control can significantly improve the adaptability and fault tolerance of the servo system.This article first introduces the basic structure of a permanent magnet synchronous motor,and analyzes the mathematical model of the motor’s motion through coordinate transformation theory.Subsequently,a vector control system of permanent magnet synchronous motor with three feedback closed loops was designed,and the design of current,speed,and position regulators was emphasized.In this paper,by analyzing the current and voltage limits on the d-q current plane,a weak flux algorithm for dual current regulators based on feedforward is proposed.This algorithm is a closed-loop control and contains two current regulators.Based on the speed and reference current,it adjusts the currents of the d and q axes to achieve field weakening.This algorithm can make the motor reach the maximum torque on the basis of meeting the current and voltage limits,and in theory can reach the maximum speed range.This paper also applies extended Kalman filtering(EKF)to the motion of permanent magnet synchronous motors,and proposes an EKF-based state estimation algorithm.And optimize the EKF algorithm,decompose and combine the matrix in the operation process,reduce the order of the matrix operation,simplify the operation process,enable the microprocessor to meet the operation needs,and improve the practicality of the EKF algorithm.The EKF algorithm enhances the adaptability and fault tolerance of the servo system.Finally,the simulation model and the actual software and hardware platform of the permanent magnet synchronous motor servo control system were built respectively.Through simulation and specific experiments,the effectiveness of the vector control system was verified and the control performance was tested.Through simulation and experimental results,it is found that the speed control of the control system can reach the set speed within0.1s;the convergence time of the position control is less than 2s,and the error of the final stability is less than 0.001%,which can meet the basic needs of the servo system.Subsequently,the effectiveness of the field weakening algorithm and the sensorless control algorithm proposed in this paper are verified,and it is found that the field weakening algorithm can increase the torque and increase the speed range by 10%;the sensorless control algorithm can replace the position sensor to perform the rotor position It is estimated that the system’s adaptability and fault tolerance are enhanced.The position error always does not exceed 0.2rad,the speed error is slightly larger at the beginning,and it does not exceed 3% after stabilization.