Research on a Mechanical Sensorless Vector Control of Induction Motor Using Image Processor

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The research project titled "Research on a Mechanical Sensorless Vector Control of Induction Motor Using Image Processor" has been carried out from 2004 to 2005 in faculty of engineering, Nagasaki University. The results obtained from this project are summarized as follows ;(1)The proposed system and its designWe have proposed a new hybrid type vector control system of induction motor in which a flux observer based speed sensorless vector control and the information of image sensor (CCD camera) are combined. The information of image sensor is useful in steady-state operation and is adapted to identify the rotor resistance. A simulation program and a linear model is derived for the analysis of proposed system.(2)Experimental systemA digital signal processor (DSP) controller, inverter, CCD camera, visual information processing board, induction motor and DC generator (load) are equipped and tested. Software which contains flux observer, speed estimation, parameter identification, current controller and speed controller is developed.(3)Simulation and experimental resultsSteady-state and transient characteristics are tested by digital simulation and experimental equipment. Since the results obtained by digital simulation are very close to the experimental results. It is confirmed that the rotor resistance identification is accomplished successfully by using the information from visual sensor. As the result, the accuracy of estimated speed is improved and good transient responses are obtained. Furthermore, the efficiency is improved by controlling the magnetizing current which minimizes the sum of copper loss and iron loss. Since the rotor speed computed by image sensor has long time lag and it is valid under steady-state operation, the vector control using this speed is impossible.