양자변환에 의한 공진형 변환기의 최적순차제어 및 회로변환에 의한 행렬변환기 특성해석

학위논문(박사) - 한국과학기술원 : 전기 및 전자공학과, 1993.2, [ vi, 168 p. ]In this thesis, resonant converter and matrix converters are modeled and analyzed with quantum transformation and circuit DQ transformation, respectively. To reduce weight and volume of the power converter, operating frequency is increased. In DC to DC converter, the PWM converters have been used predominantly stress and but the switching frequency is limited because of their switching stress and switching loss of the switching devices. Quantum resonant converters have been introduced to increase the switching frequency. In chapter II, new control scheme named optimum quantum sequence(OQS) control which minimizes the output voltage ripple of the quantum series resonant converter(QSRC) is proposed. This control scheme is so general that it is irrelevant to the magnitudes of circuit elements as well as to the input/output voltages so far as it is operating in the continuous conduction mode(CCM). This feature is verfied by appropriate simulations. In chapter III, new modified output voltage control scheme for the series resonant converter (SRC) is proposed. In this scheme, quantized output voltage is obtained by quantum duty control and one last unit voltage is continuously adjusted by phase angle control during a half resonant cycle period. Therefore the proposed control method offers a clue to get rid of the stepped discontinuity problem in the output voltage of quantum control without degrading the performance. Based on the steady state analysis, optimum quantum sequence having greatly reduced output voltage ripple is given. And in AC to AC converter, the nine switch matrix converter are modeled and analyzed. Matrix converter is very simple in structure and has powerful controllability. But the practical matrix converter is far beyond the ideal matrix converter because of its complexity due to the non ideal source such as L and C reactive components. In this thesis, the analytic expressions for the voltage gain, input power factor and so on are obtained easily ...한국과학기술원 : 전기 및 전자공학과

The Design of Filter for Hearth Liquid Level Estimation in Blast Furnace

Optimizing the tapping time of a blast furnace is important to a stable operation and life extension. To optimize the tapping time of the blast furnace, the location of Hearth Liquid Level should be recognized. There are several ways to measure the hearth liquid level in the blast furnace, such as Electromotive Force(EMF) measurement, pressure measurement by putting in nitrogen probe and manometry with strain gauge. In this paper, it will be discussed using strain gauge among the three methods. Conventional strain gauge must be revised periodically. Since, internal pressure, temperature of internal refractory material and wind pressure have effect on the strain gauge. However, static pressure value is required to compensate. To solve these problems, this paper suggests finding relationship between Hearth Liquid Level and strain gauge output, adding digital filter in strain gauge. Using the proposed method, it was possible to estimate the hearth liquid level and determine the appropriate tapping time. Usefulness of the proposed method through simulations and experimental results are confirmed.2

Automatic moving target tracking system using microprocessor

학위논문(석사) - 한국과학기술원 : 전기 및 전자공학과, 1979.2, [ [iii], 72 p. ]한국과학기술원 : 전기 및 전자공학과

The wing structure modeling of the bioinspired aerial robot

The research of the biological mimics robot which utilizes the operation of the organism is progressed on the ground, aerial, and underwater robot sector. In the field of flying robot, the research for implementing the wing movement structure of the bird and insect is progressed. The joint structure for the wing movement of the bird is implemented. The operation of the wing is simulated. For this purpose, by using the Matlab/Simulink, the joint structure of the wing is modelled. The joint movement of the wing is tested through the simulation.2