• Journal of the Korean Solar Energy Society
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• v.33 no.3
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• pp.42-50
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• 2013

Solar thermal reactor was studied for hydrogen production with a two step thermochemical cycle including T-R(Thermal Reduction) step and W-D(Water Decomposition) step. NiFe2O4 and Fe3O4 supported by monoclinic ZrO2 were used as a catalyst device and Ni powder was used for decreasing the T-R step reaction temperature. Maintaining a temperature level of about $1100^{\circ}C$ and $1400^{\circ}C$, for 2-step thermochemical reaction, is important for obtaining maximum performance of hydrogen production. The controller was designed for adjusting high temperature solar thermal energy heating the foam-device coated with nickel- ferrite powder. A Pill temperature control system was designed based on 2-step thermochemical reaction experiment data(measured concentrated solar radiation and the temperature of foam device during experiment). The cycle repeated 5 times, ferrite conversion rate are 4.49~29.97% and hydrogen production rate is 0.19~1.54mmol/g-ferrite. A temperature controller was designed for increasing the number of reaction cycles related with the amount of produced hydrogen.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.218-223
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• 2007

This paper presents a simple, robust excitation control system for synchronous generator using direct instantaneous voltage control(DIVC) method. The proposed DIVC excitation system can operate as high dynamics of power conversion system without any control gains such as Pill controller. And the transient overshoot of generator voltage can be suppressed with a simple time constant. For the continuous control of excitation system, the fast IGBT inverter system is used in this paper for exciter's field control. The proposed control scheme is verified by the computer simulations and experimental results in the prototype generation system.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.105-108
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• 1988

In this paper, a control system design method is proposed for DC motor drive. A state space model is used to control sysytem and for closed loop system the technique of pole assignment is applied. The control system is designed with state feedback theory and to improve the response further more feedforward theory is applied to control system. The microprocessor as a controller and the interfaces in the system are proposed. Digital simulation results for step changes in reference velocity and load torque are shown.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.907-908
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• 2006

The energy storage systems are being widely researched for the electric power. The operations running in a vacuum chamber mainly consists of a composite flywheel rotor, superconductor bearings, a motor/generator and its controller. Among composed the apparatus, the floating magnet bearing consists of the ring-type permanent magnets with epoxy resin impregnation for reinforcement and surface protection. In order to storage as much energy as possible, the flywheel is supposed to be rotated with very high speed. The magnetic field is analyzed by using the Maxwell 2D/3D for the simulations.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.1110-1112
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• 1996

In this paper, we propose a new approach for robust auto-tuning of PID gains using Evolution Strategy. Evolution Strategy is searching algorithm which imitate the principles of natural evolution as a method to solve parameter optimization problem and easy to use without any other special mathematical theory. Through the simulation of the speed control of a series-connected de motor, our proposed method shows more improved performance by finding optimal parameters of PID controller than a classical Ziegler-Nichols method.

• Journal of the Korean Society of Safety
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• v.21 no.4 s.76
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• pp.25-32
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• 2006

LonWorks over IP(LonWorks-IP) virtual device network(VDN) is an integrated form of LonWorks device network and IP data network. In especially real-time distributed servo applications on the factory floor, timely response is essential for predictive and preventive maintenance. The time delay in servo control on LonWorks-IP based VDN has highly stochastic nature. LonWorks-IP based VDN induced transmission delay deteriorates the performance and stability of the real-time distributed control system and can't give an effective preventive and predictive maintenance. In order to guarantee the stability and performance of the system, and give an effective preventive and predictive maintenance, LonWorks-IP based VDN induced time-varying uncertain time delay needs to be predicted and compensated. In this paper new Pill control scheme based on Smith predictor, disturbance observer and band pass filter is proposed and tested through computer simulation about position control of DC servo motor. It is shown that how can the proposed control scheme be designed to minimize the effects of uncertain varying time delay and model uncertainties. The validity of the proposed control scheme is compared and demonstrated with the comparison of internal model controllers(IMC) based on Smith predictor with and without disturbance observer.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.31 no.2
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• pp.89-94
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• 2023

Recently, domestic small airport development plans are being promoted centering on islands, and among them, Baengnyeong Island Airport is located very close to North Korea due to its geographical characteristics. In particular, since it is located in the P-518, which is prohibited airspace, it is essential to configure the arrival/departure flight procedure route similarly to the current ship in terms of securing flight safety. Therefore, in this study, a plan for airport location and facility scale was proposed by focusing on the runway operated for the purpose of aircraft operation through consultations with the Ministry of National Defense. It was proposed to meet the standards of the Airport Facility Act as an airport dedicated to domestic flights for airside facilities such as runway length and direction, target aircraft, landing pad, apron, runway and taxiway width appropriate for the topographical characteristics of Baengnyeong Island. As a result, the flight procedure is generally established as a two-way visual flight, but the 10-way arrival/departure procedure was planned to be changed to an instrument (non-precision) according to the specificity of the region. In addition, a flight procedure was established and presented for safe and systematic operation by reflecting the changes in airport facility size (landing pad, runway end safety area, etc.) following the change in instrument flight procedure in the visual flight procedure.