Research And Implementation Of Sensorless Sliding Mode Speed Control For Permanent Magnet Synchronous Motor

With the rapid development of new energy vehicles and the resource advantages of permanent magnet materials in our country,the application of permanent magnet synchronous motor has been popularized.With the advantages of high power density,wider speed range and light weight,the PMSM has been adopted by more and more electric vehicles and new energy cars and so on.Therefore,research on PMSM governing system becomes more and more hot.The application of classical control theory has developed into modern control theory.In the control system of permanent magnet synchronous motor,mechanical sensors are generally used to obtain the position information of the rotor.The sensors not only increase the volume of the motor,but also will be affected by the harsh environment,resulting in the poor accuracy of the sensors.Therefore,the sensorless control technology of the motor has important research significance.This paper will take permanent magnet synchronous motor as the research object to study its speed control and sensorless control technology.The details are as follows:Firstly,the relationship between the mathematical model of permanent magnet synchronous motor and the variables in the equation of state is studied,then the sensor vector control technology is studied,the traditional control system is established and the speed loop controller is analyzed,the linear control PI regulator is used to adjust the errors in the system,and the feasibility of the designed model is verified by simulation.Secondly,in view of the PI regulator’s problems such as poor anti-disturbance performance,fast response speed,low response overthrow and poor robustness,terminal sliding mode control was introduced,and a sliding mode speed controller based on non-singular and global fast terminal was designed to improve the controller of the speed loop.A load torque observer was designed to observe the load of the motor.The cost of torque sensor is saved.The simulation results show that the controller based on the sliding mode principle improves the speed control effect obviously.Then the sensorless control technology research,according to the mathematical model of the motor to design the traditional sliding mode observer,the use of arctangent mathematical method to calculate the rotor Angle of the motor.Then by improving the sliding mode function and using the saturation function,the tracking speed of the observer is accelerated,the time required for dynamic convergence is reduced,the chattering of the observed data is reduced,and the observation accuracy is improved.Finally,DSP is taken as the control core of the system,and the experimental platform is built by combining the driving circuit,switching power supply and permanent magnet synchronous motor.The control strategy studied in this paper is tested experimentally,and the feasibility and correctness of the research content are verified by observing the experimental waveform of the upper computer.