Several Questions Relating To Parameters Identified In The Speed Sensorless Vector Control System

The speed sensorless vector control system is one of the hot topics in the field of electricdrive system. In order to gain high precision of speed-governing and high performance of thecontrol system, the various parameters must be identified accurately. There are fourparameters that need to be identified, including motor parameters, rotor time constant, rotorflux and rotor speed. The primary aims of this paper show as follows:(1)The vector controlfunction is built to identify off-line parameters of induction motor, and the best identificationalgorithm is came up by analyzing rotor time constant based on it.(2) According to thevoltage module and current module, an improved identification method of rotor flux isproposed, and feasibility is proved by simulation.(3) By comparing the MRAS algorithm andopen-loop estimation algorithm, rotor speed is estimated. The best algorithm of rotor speedestimation is made based on comprehensive performance of system.First of all, an overview of the status and prospects of speed sensorless vector controlsystem in parameter identification is carried out in this paper. It describes the mathematicalmodel of induction motor in different coordinate, the basic method of coordinate transform.The algorithm analysis of rotor time constant, rotor flux, rotor speed and motor parametersare made. The simulation of MATLAB verifies the validity and performance of the method.Then the hardware platform is built, and the software system is introduced. Thehardware platform is mainly composed by power circuit and control circuit. Respectively, theinformation of TMS320F28332, current sample circuits and all kinds of protected circuits areintroduced in power circuit and control circuit. The software design is in CCS, which usingDSP embedded and modular programming to complete algorithm of all control modules.In the end, the stability and dynamic of the speed sensorless vector control system istested and analyzed by using an experimental platform. The results verify that the controlsystem performs rapid response and long-term stable operation whether in low speed,acceleration and different load cases.