On-line Identification Of Time Constant Of Induction Motor

Induction motor has excellent torque output characteristics, high power density, large speed range, and more and more occasions choose the induction motor as energy conversion equipment. At the same time,with the development of electronic technology and microprocessor, the control technology of asynchronous motor has been greatly promoted.In particular, due to the improvement of vector control technology and mature, the induction motor becomes easy to control.Rotor flux oriented induction motor vector control largely dependents on rotor time constant(expressed Tr). Many methods have been invented to get Tr of asynchronous motor in offline state. But in the practical application, the motor temperature changes will cause rotor resistance change up to 50%, and the phase current will cause the saturation phenomenon of the rotor flux. these factors will affect the motor field oriented control. So it is very necessary to study how to identify Tr on line.At present, the academic circles put forward a lot of schemes for the on-line identification of time constant. Through comparison and analysis of different parameter identification methods, it is found that the rotor time constant on-line identification method based on model reference adaptive has a great advantage. Through theoretical analysis anddiscussion, as well as in MATLAB simulation platform to build a model to identify the simulation, the results show that the estimator has the advantages of fast response, high identification accuracy, and can basically meet the requirements of vector control system of rotor time constant.