Research On Inverse System Decoupling Control Of Induction Motor Based On Sliding Mode Variable Structure

Induction motor is widely used in various fields about industrial production. Due to thatit is a multivariable, strong coupled, higher order nonlinear system, when the part of internalparameters change or there is external load disturbance in the process of running, theconventional control methods can’t adjust all kinds of control parameters, and can’t meetrequirements to the high performance of induction motor speed control. So to design theinduction motor speed control system with the high precision, strong robustness is more andmore urgent.First, this paper analyzes the reversibility of induction motor speed control system, byusing inverse system method. On the basis of theoretical analysis, according to themathematical model of induction motor system, construct the corresponding inverse system.Compounding the inverse system with original system, the system is decoupled into tworelatively independent pseudo-linear subsystems, the torque subsystem and stator fluxsubsystem. A linear closed-loop regulator is designed respectively to control each of thedecoupled subsystems about induction motor, and this system emphasize the direct torquecontrol effect, for achieving the precise speed control.Variable structure control with sliding mode is a nonlinear control method, and now thismethod used quite widely, because of its global robustness performance against the externalload disturbance and internal parameter changes. In view of the induction motor speed controlsystem, this article apply the method of variable structure control with sliding mode, anddesign the speed regulator of induction motor inverse decoupling control system, so that thecontrol system has better robustness and dynamic-static performance.Finally, based on the vector control of induction motor, the simulation experiment ofinduction motor is conducted by using inverse system and sliding mode variable structurespeed controller, for testing the decoupling control performance, load disturbanceperformance and robustness. The simulation results show that the proposed induction motor sliding mode inverse decoupling control system is feasible. Therefore, the solution is effectiveand reasonable.