Research On Direct Torque Control System Of Permanent Magnet Synchronous Motor Based On Double Sliding Mode

Permanent magnet synchronous motor direct torque control(DTC)has the characteristics of simple control,quick response,so widely used in ac speed regulating system,this article in view of the traditional permanent magnet synchronous motor direct torque control system transfer torque and flux ripple,not strong influence on the reliability of the system robustness and stability,and has carried on the improvement and optimization design,and through the simulation verify the feasibility of that scheme.In order to solve the problem of flux linkage and torque ripple in the traditional DTC control,the space voltage vector pulse width modulation(SVPWM)technology is introduced,and the super-helical sliding mode controller is designed at the same time.The two hysteresis regulators in the traditional direct torque control are optimized into two sliding mode controllers(SMC): torque and flux linkage.The simulation results show that the proposed control strategy can effectively resist external interference and has strong robustness.In the closed-loop speed control system of permanent magnet synchronous motor(PMSM),a sliding mode observer(SMO)is designed for the problem of high cost of sensors.For the problem of chattering in SMO,the saturation function is used to replace the traditional switching function,and the moving point is controlled in the boundary layer,which can reduce chattering to some extent.Based on the sliding mode DTC theory and combined with SMO,the design of dual-sliding mode direct torque control strategy was completed.In order to further verify the proposed scheme step.We selected TI’s digital signal processing chip TMS320F28335 as the main control chip.The power circuit,driving circuit and sampling circuit of the control strategy are designed.The test results show that SMO can accurately estimate the rotor position information of PMSM.The estimated rotor position information is used to replace the motor rotor position information in the traditional system to form a complete double-sliding mode DTC control system.Compared with the traditional DTC,the dual sliding mode DTC control system can effectively reduce the torque and flux ripple,and obtain a more stable speed.