Rotating speed evaluation method used for speed-sensorless induction motor vector controlling

Abstract

The invention discloses a rotating speed evaluation method used for speed-sensorless induction motor vector controlling. Based on an induction motor two-phase synchronous rotating reference frame state equation, the method discloses a rotating speed evaluation method with stator resistance identification. On the basis that a field current differential equation and a torque current differential equation are respectively utilized to evaluate the rotating speed, by utilizing the equivalent relationship of the both equations, the on-line identification of the stator resistance is realized. By updating the stator resistance value in real time, the above rotating speed evaluation scheme is improved. According to the invention, synchronous speed evaluation is realized without using rotor or stator linkage and without rotor resistance, and the influence of low velocity region stator resistance also is effectively improved. The method has the advantages of clear theory deduction step, simple model, high precision of rotating speed tracking, strong robustness to motor parameter change. The method is suitable for high precision controlling and has large theory innovation and application value.

Description

technical field [0001] The invention relates to the technical field of vector control of a speed sensorless induction motor, in particular to a rotor speed estimation method for high-precision and robust vector control of an induction motor. Background technique [0002] Speed ​​sensorless vector control (SVC) saves the speed sensor and cancels the related encoder disk connection, reduces the maintenance cost of the system, improves the system reliability, and lays the foundation for the integrated design of the motor. Therefore, this technology In recent years, it has received extensive attention, and how to quickly and accurately estimate the motor speed signal has become the focus of research by scholars at home and abroad. At present, the existing speed identification methods of sensorless induction motor vector control can be roughly divided into the following categories: calculation method based on motor mathematical model, model reference adaptive (MRAS) method, adapt...

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Problems solved by technology

However, both of them also have shortcomings. The first method has a small electromotive force value at low speed, and the calculation error is large, so the low-speed performance of the system is not good; the second method needs to use the rotor flux linkage or stator flux linkage, and the formula Contains the rotor resistance factor, the control accuracy is affected by the change of the rotor resistance, especially in the high-speed area

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