Research On Control Strategy Of Permanent Magnet Synchronous Motor Based On Improved Exponential Sliding Mode

Permanent Magnet Synchronous Motor has the advantages of small size,simple structure and strong robustness,which has been widely used in medical,aerospace and urban rail transit and other fields.PMSM is comprehensively used in related industries,and the requirements for motor control systems are gradually increasing,therefore it is very necessary for us to study good control algorithms for PMSM control.When sliding mode control is applied in the control system,the system still has strong robustness even if it is disturbed by the outside world.Whether in laboratory equipment or in industrial field equipment,changes in factors such as temperature,mechanical structure,and magnetism of permanent magnets inside the motor may cause changes in parameters,which will have a greater impact on system performance.Therefore,in order to ensure the good performance of the system,it is necessary for us to equip the PMSM with a suitable controller.In this thesis,surface mount PMSM is taken as the research object,and the sliding mode variable structure control theory is applied to study the control strategy of PMSM,build experimental platform,write programs and conduct experimental debugging.The specific research is as follows:Firstly,based on Clark and Park transformation,the mathematical model of PMSM in dq coordinate system is obtained and the principles of vector control and space vector pulse width modulation are introduced.Secondly,taking the speed controller as the research object,the PMSM control system is designed as a double closed-loop speed regulation system of current and speed.With the improvement of PMSM control performance requirements,the use of traditional PI controller has been unable to meet people’s requirements for the performance indicators of existing motor control systems.Therefore,this thesis based on variable structure control theory,combined with the design principle of exponential sliding mode controller,replaced the traditional symbolic function,introduced the quadratic radical function of state variable square,gave a speed controller which improved exponential sliding mode approaching law,and completed the simulation design of PMSM speed control system.Then,the PI controller,exponential sliding mode controller and improved exponential sliding mode controller are used to study the Matlab/Simulink simulation model of PMSM speed control system.The simulation results show that the improved exponential sliding mode controller is compared with the PI controller and the exponential sliding mode controller: When the motor starts,the speed overshoot is relatively small;when the motor is running smoothly,the system suffers from external disturbances,and the speed only changes slightly.It can be seen that the designed improved exponential sliding mode controller has good robustness.Finally,the dependence of EDA software is addressed to design the hardware circuit board of the experimental platform,and the experimental platform was built.Keil MDK and STM32 Cube MX were used to write the program,and then Motor Control Workbench was employed in system debugging and experiment.The experimental results show that the hardware device and controller,designed in this thesis,basically achieve the expected goals at this stage.