Research On Composite Control Of Permanent Magnet Synchronous Motor Based On Second Order Sliding Mode Method

The permanent magnet synchronous motors(PMSM)are widely used in industrial,military,aerospace and other fields due to significant advantages such as high power density,high efficiency,simple structure and lightweight.However,the PMSM is a multi-variable,strongly coupled nonlinear system,and it will be affected by the uncertainties of the external environment field.In order to improve the control performance of a PMSM,the sliding mode control theory is extended to the field of motor control.Based on the second-order sliding mode(SOSM)algorithm and disturbance observation technology,this paper studies the control problem of a PMSM.The specific content includes:a)Mathematical model of PMSM is constructed under rotating coordinate system,a new type of SOSM controller is proposed for the motor speed loop in response to the problem of "chattering" in the traditional first-order sliding mode control.The controller uses a non-negative function to limit the uncertainty of the system,retains the advantages of the traditional sliding mode algorithm,which is robust and insensitive to external interference,and effectively reduces the "chattering".A vector control simulation model of the PMSM is built in MATLAB / Simulink.The simulation results fully prove the feasibility and effectiveness of the proposed SOSM controller.b)In view of the fact that load disturbance will affect the control performance of a PMSM,a novel disturbance observer is proposed.By constructing an auxiliary system,the disturbance of a nonlinear system is estimated only by the information of the control input and output variables.The proposed second-order sliding mode controller and disturbance observer are combined to form a composite control.The disturbance observer observes the load disturbance of the system,and uses the torque current generated as feedforward compensation of the speed loop to achieve disturbance suppression.The simulation results fully prove the feasibility and effectiveness of the proposed composite control method for PMSM based on the novel disturbance observer.c)Combined with the TMS320F28335 DSP control chip produced by TI company,a specific software and hardware implementation scheme is proposed.The hardware design of the experimental platform mainly includes the design of power supply circuit,IPM drive circuit,current and voltage detection circuit and protection circuit;the software design mainly includes the design of main program and interrupt service program.Based on the above conditions,using CCS6.0 software as the development environment,using C language as the main assembly language supplemented by a mixed programming method,according to the relevant hardware circuit,write a PMSM vector control software program.Through different algorithms for experimental testing,the experimental results fully prove the feasibility of the experimental platform design and the effectiveness of the proposed control algorithm.