• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.45-48
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• 2002

This paper proposes a grid-connected inverter using the negative conductance of PV power system, which has four IGBTs and simple controller. Most of modern electric loads generate the current harmonics and the line voltage distortion. The new solar-to-ac converter(STAC) provides by emulating a negative conductance load to the line voltage, so the current harmonics from STAC is canceled the effect of the harmonics from other loads. As a result, the line voltage distortion is decreased. The proposed system have low cost, small size, and light weight compared to conventional photovoltaic converter

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1995.05a
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• pp.101-112
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• 1995

In order to improve the recovery efficiency of heavy water vapour from the atmosphere inside a reactor building, and to recover and upgrade the heavy water which escape, special treatments, such as reducing the ingress of light water vapour, are studied in the design of the CANDU reactor systems. This is considered in controlled method of the humidity over drawing fresh air through a desiccant dehumidifier which dries the air by absorption. Comparing with the moisture loads between summer and winter operations, the moisture removal rates are calculated. Those are proportional to the difference between the controlled space and the surrounding environment Installation of a new dehumidifier will be able to reduce the moisture loads from the cooling systems, improving overall system efficiency and saving operating costs.

• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.798-800
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• 1998

In recent years, advances in construction techniques and materials have given rise to flexible light-weight structures. Because these structures extremely susceptib environmental loads, these random loadings u produce large deflection and acceleration on structures. Vibration control system of structur becoming an integral part of the structural syst the next generation of tall building. The proposed control system is applied to s degree of structure with mass damping and com with conventional PID and neural network PID system.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1998.04a
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• pp.365-372
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• 1998

Recently, constructions of large and slender structures have been increased owing to the advancement of the structural technologies and that of the new light-weight and high-strength construction materials. Consequently, vibration problems of those slender structures have become a new issue in the area of structural engineering. Active control for those structures is the method that keeps the structures safe from the external loads, especially dynamic loads, by enforcing active forces derived from control devices. In this paper, a procedure for the instantaneous optimal control for structural vibration is presented. Numerical method and experiment are performed for evaluating the effectiveness of active control for reducing vibration of structures.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.4
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• pp.517-525
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• 1996

A Simple AC complex circuit analysis for LCL type series resonant converter with phase shift control is proposed. Based on these analyses, a set of characteristic curves which allows a optimal design procedure for this converter is shown, without increasing the volt-ampere rating of tank circuit Especially, inverter output peak current can be minimized in both full load and partial load conditions. The presented design considerations can make the load range wide from full loads to light loads achieving turn-on with zero voltage switching (ZVS) operation. The detailed analysis and experimental results show the effectiveness of the proposed design algorithms. (author). refs., figs., tab.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.323-325
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• 1996

The design of Intelligent Energy Saving Power System Controller (IESPSC) for Telecom DC power plants is proposed and presented in this paper. From the past experience. rectifiers for Telecom DC power plants have been operated inefficiently at light loads. IESPSC offers "novel load sharing" approach based on the knowledge of each unit's efficiency of paralleled rectifiers. Neural networks is used for identifying each rectifier's efficiency characteristic curve corresponding to load currents, which is in turn utilized to produce a system efficiency close to the maximum under all operating conditions. In addition, by limiting the number of operating units to the minimum while maintaining high efficiency at the determined loads, a drastic savings in operating cost can be achieved.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.2
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• pp.343-350
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• 2008

In this paper, a six degree-of-freedom robot arm which is very light but capable of delivering heavy loads was studied. The proposed robot arm has much higher load capacity than conventional robot arms actuated by motors with speed reducers such as the harmonic drive since a new type of robot actuator based on a closed chain mechanism driven by the ball screw was adopted. Analysis on the design scheme and on the mechanism of the joint actuator of the robot arm were made. Since the robot arm was designed very light, it has deflection in the links. To analyze this, a finite element analysis on the structure of the designed robot links was made using ANSYS software. Verifying experiments on the performance of high load capacity of the robot arm was performed by loading heavy weights on the robot arm. Through experiments. the correctness of the numerical analysis was also verified.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.2
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• pp.318-324
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• 2010

In this paper, the structure of the gravity compensator has been designed and applied to a light structure of a new 6-axis robot manipulator to enhance its torque performance. Also, analyses on the kinematics and inverse-kinematics of the manipulator have been performed. An FEM analysis has been performed on the structure of robot links to have an excellent performance of delivering 25 kg payload despite of 30kg weight, which is very light compared with other manipulators. Through the FEM analysis, the stability on the vending or fracture of the links of the robot manipulator has been verified.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.7
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• pp.841-855
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• 1999

In the present work, the effect of a flow maldistribution on the thermal and conversion response of 8 monolith catalytic converter is Investigated. To achieve this goal, a combined chemical reaction and multi-dimensional fluid dynamic mathematical model has been developed. The present results show that flow uniformity within the monolith brick has 8 great impact on light-off performance of the catalytic converter. In the case of lower flow uniformity, large portions of the monolith remain cold due to locally concentrated high velocities and CO, HC are unconverted during warm-up period, which loads to retardation of light-off. It has been also found that the heat-up pattern of the monolith ill similar to the flow distribution profile, In the early stage of the reaction. It may be concluded that flow maldistribution can cause a significant retardation of the light-off and hence can eventually worsen tho conversion efficiency of automotive catalytic converter.

• ETRI Journal
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• v.30 no.1
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• pp.164-166
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• 2008

This paper proposes a priority-based duplicate burst transmission mechanism in an optical burst switching network to enhance the probability of successful reception of bursts. The performance of the proposed mechanism is evaluated by NS2 simulations. Our results show that the burst loss rate is improved especially under light traffic loads.