Study On Controlsystem Of Induction Motor Based On Terminal Virtual Flux Orientation

The change of working conditions during the operation of induction motor will result in the change of motor parameters, which can affect the performance of the conventional vector control and direct torque control system which has high dependence on the parameters of the motor. Therefore, reducing the influence of the change of motor parameters on the control algorithm or seeking a high robustness, stability and universality control method has become a hot research topic in the field of motor driving. This dissertation presents a new control method of induction motor based on terminal virtual flux orientation, and analyzes its performance and improvement method. At the same time, its application in the field of speed sensorless is discussed.Firstly, the mathematical model of induction motor speed control system is established, which provides a theoretical basis for the proposed control algorithm and simulation analysis in MATLAB/Simulink system. Then, comparing the induction motor control method can know that the control system stability and robustness of the control system are improved with the reference position moving from the rotor position to the terminal. On the basis of this, the control system of induction motor based on terminal virtual flux orientation is designed.Based on the analysis of the principle of state observer, a sliding mode observer using lyapunov theory for speed estimation is proposed which is used in the conventional vector control strategy for speed sensorless design. The results show that the proposed speed observation method is effective. At the same time, the sliding mode observer is also applied to the terminal virtual flux oriented control system, which can extend the application range of the proposed motor control method.In order to carry out the experimental analysis of the proposed control method, an experimental platform of induction motor variable frequency speed regulation system based on dSPACE is built. The experimental results are in agreement with the simulation results, which verify the feasibility of the experimental platform. At the same time, it also shows that the proposed control method of induction motor has good robustness, stability and universality.