Research On Several Key Technologies Of Detection And Control Based On Induction Motor Variable Frequency Drive System

Induction motor variable frequency speed dirve system based on direct torque control has developed towards the high performance control system. In this paper, the research object is induction motor variable frequency speed control system,the theory analysis and research are performed concerning the speed detection and close-loop control strategies in the system. Appling new nonlinear control theory in the induction motor control system is very important to improve the performance of industrial controller.Improved active disturbance rejection control is proposed in this paper because of difficulty of establishing accurate mathematical model and parameter setting based on the traditional ADRC. Improvement ideas including three control strategies: compound ADRC based on sliding mode variable structure and ADRC, local linearization ADRC, Tornambe control(TC).The parameter setting is easy, adjustable parameter is reducing and control function is more smoothly by introducing sliding mode variable structure controller in the structure of ADRC. The compound ADRC is designed in the flux loop and speed loop to improve the static and dynamic performance and robust performance. Advanced control strategy-active disturbance rejection control(ADRC) is adopted on the induction motor direct torque control system to improve the system performance, In view of the complex structure and parameter setting difficult defects of ADRC, optimal design of ADRC has been completed. Compound control of sliding model control and ADRC(SM-ADRC), linear ADRC (LADRC) of linearization structure and Tornambe control(TC) are researched. The local linearization ADRC is a local linearization of the nonlinear combination of ADRC. Using linear extend state observe to estimate and compensate disturbance signals caused of parameter perturbation, model uncertainty and external disturbance both can reduce the design difficulty of ADRC, and the setting parameters, convenient for engineering application.; And TC controller based on relative order state feedback is another optimization controller form of ADRC. It is proven that TC controller is equivalent to the local linearization ADRC. Cascade TC control is designed in the flux loop and speed loop, simulation results show that TC control has achieved good control effect in induction motor control system.Finally, this paper completed the design of system hardware and realization of software systems, completed the ADRC variable frequency speed-adjusting of novel induction motor control system experiment. At the same time we studied the indirect detection method of rotor speed, and studied MRAS speed detection method with a rotor flux full order Flux Observer and speed detection method based on sliding flux observer, improved the indirect detection accuracy of the induction motor speed.And we compared direct detection based on optical encoder disk rotation speed and indirect detection based on MRAS speed.The research and application of improved Active Disturbance Rejection Controller with simple design and excellent performance; it is expected to replace PID and to be a new generation controller of high-performance in the control of induction motor.