• Applied Chemistry for Engineering
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• v.29 no.1
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• pp.10-17
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• 2018

POU (point of use) scrubbers were applied for the treatment of waste gases including PFCs (perfluorocompounds) exhausted from the CVD (chemical vapor deposition), etching, and cleaning processes of semiconductor and display manufacturing plant. The GWP (global warming potential) and atmosphere lifetime of PFCs are known to be a few thousands higher than that of $CO_2$, and extremely high temperature more than 3,000 K is required to thermally decompose PFCs. Therefore, POU gas scrubbers based on the thermal plasma technology were developed for the effective control of PFCs and industrial application of the technology. The thermal plasma technology encompasses the generation of powerful plasma via the optimization of the plasma torch, a highly stable power supply, and the matching technique between two components. In addition, the effective mixture of the high temperature plasma and waste gases was also necessary for the highly efficient abatement of PFCs. The purpose of this paper was to provide not only a useful technical information of the post-treatment process for the waste gas scrubbing but also a short perspective on R&D of POU plasma gas scrubbers.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.2
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• pp.263-267
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• 2015

current mine detector can't division the section if it is conducted and it needs too much labor force and time. in addition to, if the user don't move the head of sensor in regular speed or move it too fast, it is hard to detect a mine exactly. according to this, to improve the problem using one direction ultrasonic wave sensing signal, that is made up of human body antenna part, main micro processor unit part, smart glasses part, body equipped LCD monitor part, wireless data transmit part, belt type power supply part, black box type camera, Security Communication headset. the user can equip this at head, body, arm, waist and leg in removable type. so it is able to detect the powder in a 360-degree on(under) the ground whether it is metal or nonmetal and it can express the 2D or 3D film about distance, form and material of the mine. so the battle combats can avoid the mine and move fast. also, through the portable battery and twin self power supply system of the power supply part, combat troops can fight without extra recharge and we can monitoring the battle situation of distant place at the command center server on real-time. and then, it makes able to sharing the information of battle among battle combats one on one. as a result, the purpose of this study is researching a smart wearable mine detector which can establish a smart battle system as if the commander is in the site of the battle.

• Journal of the Korean Professional Engineers Association
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• v.19 no.2
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• pp.10-20
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• 1986

This paper describes a countermeasure of electric utilities and customer equipment in order to minimize an effect of sensitive electrical and electronic equipment on the voltage disturbances. After being studied, some schemes to solve were discovered. Firstly, in the electric utilities, the reduction of frequency and influence of voltage drop's time are not easy to realize because of the standpoint of effect and economy. Secondly, in the customer equipment, there are some equipment to minimize the voltage disturbances, Such as an UPSs, a noise suppressors and a power conditioners. One of them should be established on the computer control and automated systems, the electromagnetic switch of delay-release type should be adopted on the electromagnetic switch, the controlling circuit should be adopted on the variable speed motors which is being considered a countermeasure for a momentary under-voltage drops, the luminaire adhering a instantaneous restrike device should be adopted on the HID lamp. And also, the scheme of extending a setting time of relay on the undervoltage relay and the forming method of sequence which is automatic reclosing at this time of instantaneous suspension of an electric supply have been studied.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.5
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• pp.923-930
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• 2020

In modern society, various DC power supplies are required to operate the system circuits of various electric devices. A stable DC supply is essential for the normal operation of the circuit and the importance of the converter for this is very high. This study proposed a PWM DC-DC converter circuit that applied a 3-pole 2-zero voltage controller to a KY converter, a step-up DC-DC converter, to maintain a stable supply of output voltage regardless of load fluctuations. In order to prove the normal operation characteristics of the proposed converter circuit, a PSIM simulation and a circuit operation experiment on the PCB board were performed in comparison with the conventional converter circuit.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.6
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• pp.837-843
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• 2012

Asynchronous motors are widely used in many fields. The various starting methods have been developed for the asynchronous motors which have large power compared to source power. The most popular ways to start the motors are to reduce the voltage of motor's stator or change the resistance fed rotor. It is needed to the specific time to reduce the voltage and change the resistance at a specific step. We call it the switching time. It is very difficult to know the switching time exactly. It varies with different types of motors as well as load characteristics. Thus, this paper focuses on the design and development for the mathematical models of motor and load. And then it is implemented in SIMULINK in order to calculate this time. The simulation results are both compared and discussed in detail so that it can be applied for new system with various motors and loads.

• Journal of IKEEE
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• v.22 no.3
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• pp.539-547
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• 2018

Grid-connected inverter is required to cut off the power supplied to the grid at the islanding condition, immediately. For this reason, an islanding detection is an indispensable function for grid-connected distributed generation system. Slip-Mode frequency Shift (SMS) islanding detection method is very popular method to determine the grid state. SMS method supplies the reactive power to the load according to the grid frequency. In the islanding condition of grid, this injected reactive power pulls out the grid frequency from the allowable range, then the inverter system can detect the islanding condition of the grid. The SMS method can detect the islanding state well and does not generate any harmonics of the grid current. However, the reactive power would be generated and the power quality is reduced even though the grid is not islanding condition, but normal condition. In this paper, a modified SMS method is proposed to remove the reactive power in the normal condition. The performance of the proposed method is evaluated by 600W single phase inverter experimental results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.8
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• pp.40-47
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• 2010

In this paper, we propose a probability method to determine minimum capacity of energy storage system(ESS) for Micro Grid(MG). Because of high capital cost of ESS, it's very important to determine optimal capacity of ESS and for stable operation of MG and we should determine minimum capacity of ESS. The proposed method has abilities to consider forced outage rate of generators and intermittent of non-dispatchable generators and minimum capacity make MG keep energy balancing by oneself.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.12
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• pp.73-81
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• 2011

As high speed digital systems continue to use components with faster edge rate and clock speeds, transmission of the digital information, it can bring about many troubles. The increasing requirement for controlled impedance PCBs becomes both a critical success factor and a design challenge to implement a system. Especially, the noise sources in high frequency digital systems include the noise in power supply, ground and packaging, and they destroy the fidelity of signals. Therefore PCB design with impendence matching is needed to improve fidelity of signal in H/W. In this paper, we have developed an impedance control and analysis tool for multi-layer PCB design, and simulates the tracks controlled impedance with the test coupon. So, it can save the design time and support the economical PCB design.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.3
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• pp.267-275
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• 2007

This paper presents about energy input and output modeling for a flywheel energy storage system that can store and supply mechanical energy, which is emerging as one of clean energy sources, and the analysis and control of a PWM inverter system. Moreover, this paper describes flywheel's characteristics related to variations of mechanical and electrical parameters like as voltage and current versus speed characteristics formed as numerical formula and thus simulate behaviour-status of flywheel energy. Also for comparison and analysis between PI control and PDFF control, the modeling, design and analysis to the single-phase full bridge inverter with double loop feedback control is accomplished through numerical description and simulation. Finally, under load condition 0.1[pu], 1[pu]. it is validated that harmonic characteristics for voltage and current wave is controlled within 5% below even dynamics condition.

• Journal of the Korean Society for Railway
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• v.19 no.4
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• pp.468-479
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• 2016

In order to supply power to online monitoring systems that are attached to high voltage catenary or overhead wires, a wireless power transfer system is required that is able to transmit power over the insulation gap. Such wireless power transfer systems have transmitter and receiver coils that have diameters of over 10cm. This paper focused on an investigation of the sources of loss in the coils when the coils are fabricated using printed circuit board technology. Using finite element simulation results, it has been shown that the dielectric loss in the substrate was the dominant source of the total loss. It has been demonstrated that the selection of a proper dielectric material was the most critical factor in reducing the loss. For further reduction of the loss, the distributed tuning capacitor method and the slotting of the inter-turn spaces have been proposed. For the evaluation of the proposed methods, four coils have been fabricated and their equivalent series resistances and quality factors were measured. Measured quality factors were greater than 300, which means that these devices will be helpful in achieving high coil-to-coil efficiency.