Research On Speed-sensorless AC Speed Regulation System Based On DSP

Generally, AC speed regulation system need to direct speed feedback and regulation. However, the installation of speed sensor such as tachogenerator or optical encoder increases complexity in system structure and hardware overhead. So in theoretical and practical view, it is very important to research on speed-sensorless AC speed regulation system.Firstly, the theory of vector control is discussed. This paper illustrates dynamic mathematical model of three-phase induction motor, coordinate transformation and rotor field-oriented induction motor vector control system. Secondly, typical methods for speed identification in AC speed regulation system are overviewed, and the speed identification based on the model reference adaptive (MRAS) is studied. On the platform MATLAB / SIMLINK, simulation model based on MRAS is established and verified by simulating. In the actual circumstances, some effects on typical MRAS speed identification such as motor parameters change and stator current interference are analyzed theoretically, and the theoretical analysis is verified by simulating. To weaken the stator resistance change and stator current interference, an improved model MRAS speed-sensorless vector control system with TD filter is proposed. The simulation results show that the improved MRAS speed identification model has higher accuracy of control and dynamic performance than those of the old system. Finally, the design of hardware and software for the improved MRAS speed-sensorless vector control system based on DSP are researched in the paper.