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PID제어에 의한 單相 昇·降壓 整流器의 입력전류 특성에 관한 연구
徐基永,李壽欽,柳在葉,文相弼,李來一 경남대학교 신소재연구소 1999 論文集 Vol.11 No.-
Distortion Minimized of Input Current for Single-Phase Buck-Boost Rectifier is studied in the paper. To sinusoidal waveform the input current with a near-unity power factor over a wide variety of operating conditions, the output capacitor is operated with voltage reversibility for the supply by arranging the auxiliary diode and power switching device. Then the output voltage is superposed on the input voltage during on time duration of power switching devices in order to minimize the input current distortion caused by the small input voltage when changing the polarity. The tested setup, using two insulated-gate bipolar transistors(IGBT) and a microcomputer, is implemented and IGBT are switched with 20[kHz]. which is out of the audible band. Moreover a rigorous state-space analysis is introduced to predict the operation of the rectifier. The experimental and simulated results confirm that the input current can be sinusoidal waveform with a near-unity power factor and a satisfactory output voltage regulation can be achieved.
이용중,이화춘,류재엽 한국공작기계학회 2000 한국공작기계학회 추계학술대회논문집 Vol.2000 No.-
This study to embody automatic recognition of VIN(Vehicle Identification Number)character by computer vision system. Automatic recognition characters methods consist of the thining processing and the recognition of each character. VIN character and background classified using counting method of the size of connected pixels. Thining processing applied to segmentation of connected fundamental phenemes by Hilditch’s algorithm. Each VIN character contours tracing algorithm used the Freeman's direction tracing algorithm.
이용중,김태원,김기대,류재엽,이형우 한국공작기계학회 2004 한국공작기계학회 추계학술대회논문집 Vol.2004 No.-
It is necessary for managing a perfect process for degasing aluminum molten metal according to the increase of a grade of aluminum and its alloy products. There are some methods that have been used to manage a degasing process in recent years, such as an injection method that uses aluminum molten metal powder and chemicals supplier and input method that supplies argon and nitrogen, or chlorine gas by using a gas blow-tube. However, these methods show some problems, and it shows that it is a difficult process to handle, pollution due to the producing a lot of toxic gases like chlorine and fluoride gas, irregular effects, and lowering work efficiency due to the excessive processing time. The problems that are the most fatal are the producing a lot of sludge due to the reaction of aluminum molten metal with chemicals, loss of metals, and decreasing the life of refractory materials. In order to solve these problems, this paper develops a technology that is related to aluminum continuous casting molten metal and monolithic degasing apparatus. A degasing apparatus developed in this study improved the existing methods and prevented environmental pollution with smokeless, odorless, and harmlessness by using a new method that applies argon and nitrogen gas in which the methods used in the West and Japan are eliminated. The developed method can significantly reduce product faults that are caused by the production of gas and oxidation because it uses a preprocessed molten metal with chemicals. In addition, the amount of the produced sludge can also be reduced by 60~80% maximum compared with the existing methods. Then, it makes it possible to minimize the loss of metals. Moreover, the molten metal processing and settling time is also shortened by comparing it with the existing methods that are applied by using chemicals. In addition, it does much to improve the workers' health, safety and environment because there is no pollution. The improvement of productivity and prevention effects of disaster from the results of the development can be summarized as follows. It will contribute to the process rationalization because it does not have any unnecessary processes that the molten metal will be moved to an agitator by using a ladle and returned to process for degasing like the existing process due to the monolithic configuration. There are no floating impurities due to the oxidation caused by the contact with the air as same as the existing process. In addition, it can protect the blending of precipitation impurities. Because it has a monolithic configuration, it can avoid the use of additional energy to compensate the temperature decreasing about 60? that is caused by the moving of molten metal. It is not necessary to invest an extra facilities in order to discharge the gas generated from a degasing process by using an agitator. The working environment can be improved by the hospitable air in the factory because the molten metal is almost not exposed in the interior of the area.
단면의 성질을 적용한 크기와 회전 변화에 불변인 영상 검사 시스템
이용중,김태원,김기대,류재엽 한국공작기계학회 2001 한국공작기계학회 춘계학술대회논문집 Vol.2001 No.-
The purpose of this paper is to develop image inspection system endows an automatic operating and measuring that the moment values are invariant with respect to variable object size and rotation. In this paper, using these moment feature vector with Hu's 7 invariant moment is also given. The charasteristics of section which is applied in the mechanics used moment descriptor of invariant moment detection algorithm for image inspection system. Corresponding rates between 94% and 96% have been achived for all object tested.