Research On Induction Motor Vector Control System Based On Internal Model Decoupling

The induction motor is a high-order,multi-variable,and strongly coupled nonlinear system.At the same time,many complex characteristics such as uncertainty and time-delay are difficult to control.At present,the stator current decoupling controller and the speed controller often adopt the traditional PID control strategy,but in the case where the dynamic performance is high,the traditional PID control strategy cannot meet the expected target.Therefore,this paper applies the internal model control strategy and the fractional order control strategy to the induction motor speed control system to further improve the dynamic performance of the system.Firstly,this thesis studies the principle of vector control,and derives the mathematical model of three-phase stationary(abc),two-phase stationary(??)and two-phase rotating(dq)coordinate systems and three coordinate systems based on the vector coordinate transformation principle.The transformation relationship between the mathematical models describes the induction motor vector control method and the space vector pulse width modulation technique according to the rotor field orientation.Secondly,the principle,nature and design method of internal model control are discussed.The internal model control method is introduced into the stator current decoupling controller.In order to improve the dynamic response performance of the system,the internal model decoupling stator current controller is designed.The controller adjustment parameters are easy to set and simple in structure.The simulation and experimental results verify the correctness of the internal model control in the induction motor speed control system.In order to further suppress the system overshoot and improve the rapidity,this paper introduces the fractional order control method based on the internal model decoupling control system,and designs the fractional speed controller.Compared with the integer-order controller,the controller can increase the range of integral differentiation,and the adjustable range is wider and finer,which makes the system control more flexible.