Research On Control Method Of Low Speed DC Motor

With the advantages of simple structure,high energy density and controllability,permanent magnet synchronous motors are widely used in electric vehicles,CNC machine tools,satellite antenna control and other applications.With the development of PM synchronous motor control theory,the control performance of PM synchronous motor has been improved in a wide range of speed regulation,but there is still room to improve the speed output performance of PM synchronous motor at low speed.This project focuses on the speed output stability and dynamic response performance of PM synchronous motor in low speed operation,builds an experimental platform for PM synchronous motor,and improves the speed output servo performance of the motor from the perspective of observer and controller improvement.First,the basic structure and classification of permanent magnet synchronous motor are introduced,and the mathematical model inside the permanent magnet synchronous motor is described.The vector transformation and the process of vector control are introduced.The MATLAB/simulink-based permanent magnet synchronous motor model is built,and simulation experiments at low speed are conducted,and the reasons affecting the speed servo performance of the permanent magnet synchronous motor at low speed are briefly analyzed.After that,the hardware platform of the PM synchronous motor experiment is built.The software design process of PM synchronous motor control based on STM32 main control board is introduced,and the technical implementation of phase current sampling,encoder angle measurement,SVPWM output,PI controller and other modules are described respectively.In the latter,the Kalman filter is designed to improve the stability of the speed output at low speed,and the variable parameter Kalman filter is improved and designed based on the original filter according to the speed pulsation characteristics of the permanent magnet synchronous motor at low speed.In order to improve the dynamic response performance of the speed output at low speed,a second-order self-turbulence controller is designed to replace the original cascaded PI controller.Finally,low-speed control experiments were conducted on the completed permanent magnet synchronous motor experimental platform to compare the effect of speed output under the original cascaded PI control.The experimental results verified the effect of the proposed improved algorithm on the speed servo performance of the permanent magnet synchronous motor at low speed.