• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.247-250
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• 2001

This paper presents a simple and cost effective circuit topology of single-ended type high frequency quasi-resonant PWM inverter using IGBTs, which can operate under wide soft switching operation range based on ZCS for main power switch as compared with a conventional active voltage-clamped ZVS-PWM high frequency quasi-resonant inverter developed previously. In principle, this new circuit topology can efficiently operate under a constant frequency PWM control-based power regulation scheme. In particular, it is noted that the zero current soft switching (ZCS) commutation can achieve for the main active power switch. On the other hand, the zero voltage soft switching (ZVS) commutation can also achieve for the auxiliary active power switch. The operating principle of this high-frequency Inverter treated here and its power regulation characteristics are illustrated on the basis of the simulation and feasible experimental results.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.191-194
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• 1997

Passive, semi-active and active dampers have been used to dissipate energy in mechanical systems. Semi-active dampers have higher performance than passive dampers and require lower power to operate than active dampers. Its damping characteristics can be changed appropriately for varying conditions. In this paper, we developed a semi-active damper based on Magnetorheological(MR) fluid. MR fluid has a variable damping characteristics proportional for the magnetic field intensity. It has several advantages such as high strength, low viscosity, robustness in impurities and wide temperature range of operational stability. We designed a constrained rotary MR damper base on valve mode which can dissipate more energy per unit volume. The system with Bingham characteristics is obtained and proved by the experiment.

• Journal of Electrical Engineering and Technology
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• v.12 no.5
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• pp.1812-1820
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• 2017

This paper analyzes a symmetric active cell balancer for a battery management system. The considered cell balancer uses a forward converter in which the circuit structure is symmetric. This cell-balancing method uses fewer switches and is simpler than the previously proposed active cell-balancing circuits. Active power switches of this cell-balancing circuit operate simultaneously with the same pulse width modulation signals. Therefore, this cell-balancing circuit requires less time to be balanced than a previous bidirectional-forward-converter-based cell balancer. This paper analyzes the operational principles and modes of this cell balancer with computer-based circuit simulation results as well as experimental results in which each unbalanced cell is equalized with this cell balancer. The maximum power transfer efficiency of the investigated cell balancer was 87.5% from the experimental results. In addition to the experimental and analytical results, this paper presents the performance of this symmetric active cell-balancing method.

• The Journal of Korea Robotics Society
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• v.17 no.2
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• pp.216-220
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• 2022

This paper proposes an inspection robot that can operate on a single square rail. Various inspection robots have been developed to identify emergency situations in industrial environments, such as those involving fires or individuals with cardiac arrest. Because the robots must operate in wide areas and long tunnels, they are designed to move along a rail installed on the ceiling. Double rail track are typically used to ensure the stability of robot movement. However, the cost for installing a double rail track is nearly two times that for a single rail track. Moreover, it is challenging to install double rail tracks while ensuring the same curvature and interval between the two rails. Therefore, in this study, an inspection robot that operate on a single square rail track is developed. To ensure stable movement in the longitudinal and lateral directions, two passive guide parts are used, and the main active wheel is allowed to move on the upper side of the square rail. The prototype was manufactured, and experiments were performed for different robot velocities.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.10a
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• pp.168-175
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• 1999

The previous study was an expert system development that help engineers select proper foundation types and construction methods for structures under various subsoil condition. The system includes geographical and geological data in certain areas of Ulsan and a knowledge base for the selection of foundation types. However, the system, a kind of application program, has a weakness that it can be used only when it is installed at each user's own computer. Therefore, the purpose of the research is to more the system operated on Internet and spread over to more users. So, Server Installation, ActiveX, ADO(Active Data Objects) and ASP(Active Server Pages), which are the requirements to operate the system on Internet, are to be investigated through the research.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.50 no.3
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• pp.130-137
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• 2001

In this paper, we propose a new Active Noise Filter Control System which operate as a control performance when a adaptive filter fault. In this system, half-fixed filter which is new filter, connected to parallel with adaptive filter. An adaptive filler use to continuous parameter estimating, but adaptive filter is fault, half-fixed filter update newly data which is continuous estimating date each during sampling period. We simulate and apply the proposed active noise filter system to in the cylinder type duct. Experimental results show that proposed Active Noise Filter Control System has better control performance than existing filter which Eriksson's or Parallel Filter System in term of noise reduction.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2006.03a
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• pp.495-502
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• 2006

Seismic performance of semi-active fuzzy control algorithm to operate MR dampers for coupling adjacent building is investigated in this paper. In the proposed semi-active control technique, the fuzzy logic is used as a method to adjust input voltage to MR damper. In order to validate control performance of proposed technique, the seismic performance of the semi-active fuzzy control system is compared with that of passive control system where the input voltage to MR damper is set to display maximum damping force. The simulated results show that the semi-active fuzzy control technique effectively regulates the trade-off existing between seismic responses of two buildings subject to various earthquake excitations.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.301-303
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• 2001

This paper proposes the boost input type active clamp DC-DC converter featuring the high efficiency and improved EMI characteristics. The main characteristic of the converter is to operate with the non-pulsating input and output currents. Besides, it has the zero-voltage switching (ZVS) and low voltage stress characteristics. For the proposed converter, the detailed operation principles and the simulation results are presented.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.11
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• pp.23-29
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• 2008

This paper presents a new conceptual electromagnetic induction eddy current based stainless steel plate spiral type heater for heat exchanger or dual packs heater in hot water system boiler steamer and super heated steamer, which is more suitable and acceptable for new generation consumer power applications. In addition, an active clamping quasi-resonant PWM high frequency inverter using trench gate IGBTs power module can operate under a principle of zero voltage soft commutation with PWM is developed and demonstrated for a high efficient induction heated hot water system and boiler in the consumer power applications. This consumer induction heater power appliance using active clamping soft switching PWM high frequency inverter is evaluated and discussed on the basis of experimental results.

• Journal of Electrochemical Science and Technology
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• v.10 no.4
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• pp.381-386
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• 2019

Zn-air battery uses oxygen from the air, and hence, air holes in it are kept open for cell operation. Therefore, loss of water by evaporation through the holes is inevitable. When the water is depleted, the battery ceases to operate. There are two water consumption routes in Zn-air batteries, namely, active path (electrolysis) and passive path (evaporation and corrosion). Water loss by the active path (electrolysis) is much faster than that by the passive path during the early stage of the cycles. The mass change by the active path slows after 10 h. In contrast, the passive path is largely constant, becoming the main mass loss path after 10 h. The active path contributes to two-thirds of the electrolyte consumption in 24 h of cell operation in 4.0 M KOH. Although water is an important component for the cell, water vapor does not influence the cell operation unless the water is nearly depleted. However, high oxygen concentration favors the discharge reaction at the cathode.