Research On Permanent Magnet Synchronous Motor Control Based On Fractional Sliding Mode Observer

With the development of computer control technology and power electronics technology,permanent magnet synchronous motor(PMSM)has been widely used in manufacturing,new energy vehicles and household appliances.In the traditional PMSM control system,vector control and direct torque control occupy the main position,but the inherent current inner loop of vector control makes the system response slower;direct torque control has the disadvantages of poor performance of low-speed control and large torque ripple.In recent years,the finite control set model Prediction Current Control(FCS-MPCC)has emerged,which is a new computer online optimization control algorithm.FCS-MPCC does not need the precise mathematical model of the control object.It has better restraint ability for the control object with non-linear relationship,and can reduce the current and torque ripple,improve the dynamic and steady-state performance of the system.In general,the speed regulator in the FCS-MPCC control system uses a linear controller such as PI,which is less robust and difficult to achieve high performance control of PMSM.In this dissertation,the fractional order theory and sliding mode control theory are combined to design the fractional order integral sliding mode controller(FOISMC),which improves the shortcomings of the traditional sliding mode regulator and makes the designed regulator have the advantages of sliding mode control and fractional order control.Accurate acquisition of speed and rotor position angle is essential for achieving high-performance control of the motor.In traditional PMSM control systems,which are generally measured by mechanical sensors,the application of mechanical sensors increases system cost and reduces system reliability.In this dissertation,the fractional order sliding mode observer(FOSMO)is designed to achieve accurate acquisition of the rotational speed and rotor position angle information.The control performance of the system is also discussed.The research content of this dissertation includes:(1)The model predictive current control algorithm is studied,also,the model of model predictive current control system is built to reduce the ripple of stator current and torque and enhance the robustness of the system.(2)The design method of integral sliding mode controller is studied.The integral initial value is selected to ensure the global robustness of the system,and the new approach law is used to reduce the chattering phenomenon.The design method of load observer is studied to further enhance the anti-load disturbance ability of the system.(3)On the basis of model predictive current control system based on fractional order integral sliding mode controller,a FOSMO is designed to estimate the speed and rotor position angle quickly and accurately.Also,it is compared with integer-order sliding mode observer and MRAS observer.