Research On Induction Motor Speed Sensorless Control System Based On Sequential Dual Extended Kalman Filter

As we all know, the advantages of induction motor are reliable, low cost and adaptive to harsh environments. The vector control technology not only maintained the advantages of induction motor, but also improved the speed control performance significantly. However, the traditional vector control system needs to install the speed sensor, which reduces the security, reliability, and environmental adaptability of the induction motor control system. Therefore, the speed sensorless vector control technology of induction motor becomes a research focus recently years. Through deeply analysis the problems of traditional speed sensorless control system, a new speed sensorless control system with alternately sequential dual extended Kalman filter is proposed, which can realize the identification of the motor speed and parameters at the same time. This paper carried out intensive research in the aspects of its working principle, simulation model, implementation scheme and so on.Firstly, the mathematical models of induction motor are derived in three-phase static, tow-phase static and two-phase rotating coordinate system. The basic principle of the EKF state observer for induction motor speed sensorless vector control system is also detailed analyzed in this thesis. The control performance and influencing the factors to the control system are researched in deeply at last.Secondly, against the problems that the speed identification precision of traditional EKF observer is affected by the change of motor parameters and so on, an alternately sequential dual EKF observer with a fading factor is proposed, which can realize the identification of speed and parameters simultaneously. The state equation and recursive process of the observer is studied in-depth. What's more the computation of the proposed observer is analyzed and compared to the existing algorithm.Again, an induction motor speed sensorless vector control system is designed using the proposed algorithm. The system consists of double closed loop of the speed and flux outer ring the current inner ring. The simulation model of induction motor speed sensorless vector control system is established with the MATLB7.1/Simulink platform, which realized the identification of the motor speed and parameters simultaneously. In addition, the performance of the control system with the proposed algorithm is simulation studied.Finally, the software and hardware for TMS320F2812-based induction motor control system is designed. An experimental platform is built and the experimental research is conducted. Both the simulation and experimental results proved that the proposed induction motor state observer is correctness and feasibility.