Research On Induction Motor Parameter Identification Based On MRAS

With the rapid development of power electronics, semiconductor device and control technology, induction motor drive has been widely applied in industry and agriculture. However, the research on AC speed regulation system was initiated late in our country. Nowadays, the performances of the domestic products are much poorer than the foreign products, and market share is relatively small. So it is urgent to study the induction motor drive system, which can make domestic products with intellectual property right (IPR) more competitive in the international market.Induction motor is a multi-variable system with strongly coupling characteristic. The vector control based on rotor flux orientation, which is a high-performance speed control method, can realize decoupling control of speed and flux. The flux estimation is an important task in implementing high-performance speed control system, therefore in this dissertation the flux observer will be well studied. First, based on the analysis of the observer with an adaptive orthogonal compensation, an improved flux observer which can effectively solve the pure integration problem and extract input DC bias is proposed in this dissertation. Then, two MRAS parameter identification methods are analyzed, namely the rotor time constant identification and the simultaneous identification of rotor time constant and stator resistance. By adopting MRAS parameter identification, the results of flux observer are not affected by the variation of rotor time constant and stator resistance anymore. Based on theoretical analysis, the validation of the improved flux observer and MRAS parameter identification in the induction motor vector control system is proved through simulation and experiment. Finally, the design and implementation of induction motor vector control system is introduced in this dissertation, including the system configuration and the software design of digital control platform.