Parameter Identification Of Asynchronous Motor And Adaptive Control Strategy Research

With the development of field orientation technique, the vector control technology of AC transmission can basically reach to the same level at dynamic and static performance of the DC transmission. Whereas, the vector control of asynchronous motor requires precise observation of rotor flux in order to achieve the oriented control of stator current and rotor field, and accurate motor parameters are the base. Motor parameters are susceptible to temperature, magnetic saturation and skin effect in the operating process of the motor, which may cause the inaccurate rotor flux observation, so as to affect the vector control. Vector control is first and foremost to estimate rotor flux so that realize the rotor field orientation control. The second is to estimate rotor speed to achieve the speed sensorless vector control. Last but not the least, the parameters of velocity loop, current loop and magnetic link can be self-tuning, thus improving the dynamic and static performance of the system.Many articles have introduced the using of least squares method on parameter identification so far. This article gives the detailed analysis of on-line and off-line motor parameter identification based on the recursion method of least square (RLS) algorithm. Using RLS algorithm on parameter identification can simplify the two-dimensional model, and avoid the two-dimensional matrix inversion operation question to reduce the computation load. Solve the Butterworth digital filtering equation of state with the improved Euler numerical solution, while get the signal filter value and figure out the signal first derivative value and second derivative value in the meantime, which has avoided the influence of derivative discretization error, increased the operation precision. According to the massive simulations and experiments in view of the different power’s electrical machinery studies, the experimental result has confirmed its good stability, consistency and accuracy.In the meantime, in this article, using the AC-DC off-line identification algorithm on motor parameter off-line identification are analyzed, turns out this algorithm can reduce the microcontroller operating speed and memory capacity. And it is verified through repeated experiments of different power on asynchronous motor identification that the higher practicality of the method.The article also introduces the extended kalman filter (EKF) algorithm theory and its application in motor adaptive control. Set up a simulation model of the speed sensorless vector control system based on EKF algorithm in Simulink simulation environment, observe and estimate the rotor flux and speed, which have led to good motor control results. In addition, the speed sensorless vector control based on EKF algorithm has good rapidity, stability and accuracy that have been verified by the simulation results.