Research On High-Performance Speed Control Of Induction Motor

Induction motor has the advantages of simple structure,convenient manufacturing,low cost,durability,reliable operation,and can be applied to the worse working conditions.Induction motor speed regulation system has become the main development direction of motor drive system,especially induction motor servo system with high precision and high-performance requirements has broad development space and application prospects.To achieve high-quality control performance,higher requirements are imposed on the control strategy.Therefore,it is of great practical significance to study the high performance speed control method of induction motor.In this article,firstly,the mathematical models of induction motor under different coordinate ststem are presented according to the coordinate transformation theory.Baesd on vector control strategy,the magnetizing and torque current of the induction motor is decoupled successfully.Moreover,SVPWM method is introduced to improve the utilization of DC bus supply voltage.Secondly,the rotor field oriented control technology is studied.The observation accuracy of rotor flux directly affects the effect of vector control.Aiming at high performance control,a rotor flux observer based on super-twisting sliding mode algorithm is designed,which has high precision and great robustness to rotor time constant variation.In addition,the proposed rotor flux observer is used as the reference model of the model reference adaptive system,while the adaptive model is the current model with rotor time constant.By means of MRAS theory,the rotor time constant can be estimated under the appropriate adaptive law.Next,the design principle of active disturbance rejection control(ADRC)method is analized in detail and also applied to the induction motor speed control system.Considering that the parameter tuning process of the ADRC controller is more complicated,a linear ADRC controller is used in the speed loop in stead of traditional PI controller to improve the anti-interference performance of the system.At the same time,in order to improve the dynamic performance,the inertia of the induction motor system is estimated to adjust controller parameter.Using the periodic speed reference signal,the inertia of the machine can be estimated according to the relationship of the mathematical orthogonality of the internal state variables in the disturbance observer.Then,in the current loop,an improved current predictive control based on a linear extended state observer is proposed,thereby improving the dynamic response performance and robustness to parameters variation.Finally,an experiment platform based on TMS320F28335 DSP chip of TI company is designed and built.The hardware and software of the speed control system of induction motor is realized,and the feasibility and effectiveness of the control algorithm proposed in this paper are verified.