• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.9 no.4
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• pp.78-85
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• 1995

This paper covers stability and stabilization of Multi-Excited Induction Motor used in numberous electric equipment system of industrial field. The induction motor with multi-excitation has tow sets of three-phase system : One is connected to the AC source to supply most power required at the load, and the other is to the inverter for variable frequency and/or magnitude of voltage. The conventional induction motor is operated under single excitation mode only, that is called induction mode. But in multi-excited induction motor both the induction mode and the synchronous mode are possible, and the proposed multi-excited induction motor can be driven as a synchronous motor by the extra three-phase input. At the synchronous mode the efficiency is improved so higher than that at induction mode or conventional induction motor. The rating of the inverter used for speed control of numberous electric equipment system can be reduced upto one-tenth of that for conventional induction motor. Also the cost and maintenance fee of multi-excited induction motor can be reduced compared to any other motor.

• Journal of Fisheries and Marine Sciences Education
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• v.26 no.2
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• pp.444-454
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• 2014

The range of optimization problem in aquaculture is very wide, resulting from the range of species, mode of operation. Quite a few studies focus marine net-cages, but studies on land based culture farm are few or no. This paper considers a allocation problem to meet production planning in land based aquaculture system. A water pool allocation model in land based aquaculture system was developed. The solution finds the value of decision variable to minimize yearly production costs that sums up the water pool usage cost and sorting cost. The model inputs were (1) the fish growth rate (2) critical standing corp (3) number of water pool (4) number of fish. The model outputs were (5) number of water pool in growing phase (6) cost of cultivation (6) optimal facility allocation(number of water pool for each growing phase). To solve the problem, an efficient heuristic algorithm based on a greedy manner is developed. Branch and bound and heuristic is evaluated through numerical examples.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.10
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• pp.970-977
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• 2007

Absolute position detector which is one of the major equipment in the field of factory automation, not only perceives the absolute position of the rotary machine but also outputs switch data according to the given angle. Absolute position detector is composed of sensor module and its controller. In this paper, a sensor driver is implemented using FPGA with VHDL. This chip has a less form factor than conventional circuit. A test shows reliable precision within THD(total harmonic distortion) of 0.2% which can be applicable commercially. Also, FPGA-based phase error compensation methods were newly discussed. In the future, more research will be conducted to enhance the precision by the introduction of 3-phase transformer.

• Journal of Advanced Marine Engineering and Technology
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• v.17 no.3
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• pp.70-79
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• 1993

The application of A.C. motor to servo system is rapidly increased according to the recent advance of power electronics and digital control techniques. The induction motor which has a simple structure and needs less maintenance is used in the industrial field for the variable speed and position control recently. In this paper, the current characteristic of the full-bridge resonant inverter is studied by comparing with the computer simulation and the laboratory experiment when the ratio of forced frequency to the natural frequency and the ratio of conduction time to the period at the given frequency is changed. And then, the full-bridge resonant inverter is applied to the speed control of single phase induction motor.

• Journal of the korean Society of Automotive Engineers
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• v.7 no.4
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• pp.49-56
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• 1985

This study consists of instrumenting and running tests on variable compression engines and measuring the following combustion characterics: (a)flame speed, (b) emission and (c)performance parameter such as power and economy. The results were as follows: 1) The phase separation diagram of substitute fuels were obtained from phase separation experiment. 2) The flame propagation speed of substitute fuels were higher than gasoline and increased with increasing methanol weight percent of substitute fuels. 3) BEMP of substitute fuels was slightly less than that of gasoline but in the range of small weight percent, BEMP was compatible to gasoline. 4) Concentration of NOx decreased significantly with delaying spark advancing time. Also, it decreased for rich equivalence ratio but increased with high compression ratio. In general, NOx concentration was much lower than that of gasoline. 5) Concentration of HC and CO increased for rich equivalence ratio. Also it was lower than that of gasoline.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.1 no.2
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• pp.70-73
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• 1987

This paper itltroduces a simple stair-case PWM using the pseudo-sinusoidal method. In a configuration of controller, the value of sine as a fundamental factor divided into stair-case level and the three-phase PWM inverter is composed by digital compound for each value of stair-case level. The three-phase output pulse at a fixed carrier frequency and a variable reference frequency is obtained under the effect of reduced harmonics. In this experiment, using the power FET as the switching device, 0.5 H.P. induction motor operation is performed when the switching frequency is 20KHz.

• Proceedings of the KIPE Conference
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• 2009.11a
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• pp.139-141
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• 2009

This paper presents a design and analysis of torque characteristics of a two-phase SRM(Switched Reluctance Motor) for high speed blower system. To reduce the electrical frequency and core losses at high speed region, In order to reduce torque ripple and torque dead-band, variable rotor air-gap structure is adopted and the air-gap is optimized according to torque production. The optimized torque output is verified by the FEM results.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.422-428
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• 2011

금속을 청정 에너지원으로 이용하기 위해 분말형 금속연료 연소시스템이 필요하고, 이에 대한 선행연구로 분말을 정량 공급할 수 있는 공급기를 설계 제작하였다. 유동층 방식의 분말 공급에 영향을 미칠 수 있는 변수들을 피스톤 및 벤츄리관이 적용된 공급 방법을 사용하여 통제한 후, 조절 가능한 공급기 내부 압력만을 변수로 하여 중요 성능인 분말 공급량을 직접적인 중량 측정 방법으로 측정하였다. 측정 실험의 결과로부터 연소시스템에 적용할 공급기의 작동 조건을 도출할 수 있었고, 작동 조건에서 벗어난 영역에서 분말 공급기가 가지고 있는 문제점을 확인하였다.

• Journal of the Korean Society of Combustion
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• v.15 no.4
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• pp.22-28
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• 2010

The Direct Quadrature Method of Moments (DQMOM) has been presented for the solution of population balance equation in the wide range of the multi-phase flows. This method has the inherently interesting features which can be easily applied to the multi-inner variable equation. In addition, DQMOM is capable of easily coupling the gas phase with the discrete phases while it requires the relatively low computational cost. Soot inception, subsequent aggregation, surface growth and oxidation are described through a population balance model solved with the DQMOM for soot formation. This approach is also able to represent the evolution of the soot particle size distribution. The turbulence-chemistry interaction is represented by the laminar flamelet model together with the presumed PDF approach and the spherical harmonic P-1 approximation is adopted to account for the radiative heat transfer.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.3 no.4
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• pp.257-262
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• 2002

A design method of a power controller for controlling the temperature adopted in RTP (rapid thermal processing) which uses the phase control method is presented. The power controller is fabricated by using the design method presented in this paper and is tested. As the results, the range of average voltage from the variable output is 0∼198.06 V and the control resolution is 48.356 mV (12 bit) at the range of the input signal (0∼10 V).