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The Motor’s Parameter Identification Research to Vector Controlled Inverter Used in Asynchronous Motor

Author: DuanLiang
Tutor: MoJinQiu；CaoJiaYong
School: Shanghai Jiaotong University
Course: Mechanical Design and Theory
Keywords: Asynchronous motor Vector control Off-line motor’s parameter identification On-line motor’s parameter identification Model reference analyze system (MRAS)
CLC: TM921.5
Type: Master's thesis
Year: 2012
Quote: 0

Abstract

 Vector control has some special advantage compared with other AC speed regulation method, such as Direct Self-Control, so it is the most widely used technology in AC speed regulation area. Actual motor’s parameters are the key to maintain the inverter’s control quality which adopted vector control. At present in practical applications, the motor’s parameters are got through off-line parameter identification program which also offers initial value to the vector control. Although off-line parameter identification method could get the motor’s parameters, the motor’s parameters will change in the run process of the motor. People usually use parameter identification technology and intelligent control theory to reduce the affection to motor’s operation performance caused by this problem.Based on the motor’s basic fundamental equation and inverter’s hardware structure designed in this thesis, an off-line method is proposed to identify motor’s parameters. This method could be used to identify the motor’s stator resister, rotor resister, leakage induction and mutual induction while keep the motor in standstill status. So the initial motor’s parameter value of inverter could be got through this method. In order to improve the accuracy of the identification result, a method based on DFT theory is proposed to calculate those values. Considering the errors caused by asynchronous measurement and DFT calculation process, an improved method based on DFT theory is proposed to calculate the stator current’s amplitude and initial phase. To solve the problem of motor’s parameters changing with time, an on-line identification method is proposed to identify motor’s time constant on the base of MRAS theory, which has simple calculate process and suits to the on-line calculation in DSP platform. On the base of inverter’s hardware, the off-line parameter identification experiment is designed and some experiment results are given in this thesis. At the same time, the motor’s on-line parameter identification model is built in the Matlab/Simulink environment; some simulation result of on-line parameter identification algorithm under different conditions is given and analyzed in the thesis.

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