Research On Extended Kalman Filter For Direct Torque Control System Based On DSP

On the basis of researching the development of speed sensor-less control system and the control strategy of Direct Torque Control (DTC) of AC induction motor, Extended kalman filter (EKF) for speed sensor-less DTC of induction motor drive system, to improvement the performance of DTC, is presented in the paper. The design of AC hardware control system based on TMS320F240 DSP is discussed in this paper. Theoretical analysis, digital simulation and real implementation are to verify the validity of the proposed estimation technique.Performance of the system of DTC depends greatly on the accuracy of the estimation of the stator flux and rotor speed, which in turn depends on the proper models and the accuracy of the monitored currents and voltages. EKF is designed for stator flux and rotor speed estimation in the closed loop control, which can decrease the errors of measured voltages and currents, improve the accuracy of stator flux estimation, and estimate speed for implementing speed sensor-less control, moreover integrate the flux model into the filter.In order to confirm the feasibility of real time implementation the proposed strategy, the hardware control system mainly made of DSP F240 and IPM is designed. The research programs using fixed-pointed DSP assembly language and debugs with CC2000 software to realize the control strategy.The results of digital simulation with MATLAB/SIMULINK and real-time experiment based on the designed hardware platform show that EKF the estimation of stator flux and rotor speed using EKF is good , and can improve the control performance, specially at low speeds, on the other hand the results demonstrate the hardware design is practicable...