Research On Sensorless Control Of Induction Machine Based On Voltage And Current Model Flux Observer

With the development of power semiconductor devices, power electronics technology and speed sensorless vector control technology, induction machine speed control system is more and more widely used. Flux observing and speed estimating are the key technology for the realization of speed sensorless control of induction machine. Based on the survey of the two key technology, this dissertation focuses on the research of the speed sensorless vector control system, which is based on voltage and current model flux observer and model reference adaptive system speed estimating method.Firstly, the traditional voltage and current model flux observer is selected for further investigation. The existence of unstable region of this observer in generating-mode is illustrated through small signal model analysis and the scope of the unstable region is given. And then the improved voltage and current model flux observer is proposed, and it realizes full range stable work. At the same time, MRAS speed estimating method is studied with the improved voltage and current model flux observer as the reference model.Secondly, due to the change of motor parameters in the actual operating while the operating statue changes, parameter sensitivity of the improved voltage and current model flux observer and MRAS speed estimating method is studied. According to the influence of motor parameters, MRAS based stator resistance online identification and signal injection based rotor resistance online identification method are studied.Finally, simulation platform and experiment platform of speed sensorless vector control of induction machine are set up. The method of flux observing, speed estimating and online identification of stator resistance and rotor resistance are evaluated through simulation and experiment. Thus speed sensorless vector control of induction machine is realized.