• Journal of Power Electronics
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• v.18 no.2
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• pp.383-394
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• 2018

This paper presents an isolated power factor correction converter for general-purpose electric vehicle chargers with a wide output voltage range. The converter is based on an asymmetrical dual active bridge structure so that the voltage stress of switching devices can be eliminated by transferring the transformer leakage inductance to the circuit parameters. Harmonic and output controls are performed by secondary switches, and primary switches are only operated at a fixed frequency with a 50% duty ratio. A harmonic modulation technique is also adopted to obtain a near-unity power factor without input current monitoring. The feasibility of the proposed charger is verified with a 3.3 kW prototype.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.1
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• pp.16-18
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• 2010

This paper presents monitoring system based on IEC61400-25 for 750kW-class DFIG wind power generation system. It consists of wind turbine PLC, Local and Remote I/O Server, human machine interface, and Web-server. Proposed System has been demonstrated in Daegi-ri, Kangwon-do, which aims to test IEC61400-25 communication capability of monitoring system and evaluate the performance of 750kW-class WTS.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.4
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• pp.206-212
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• 2017

In this paper, using the power system information obtained from real-time monitoring device, to analyze the voltage stability margin index and described the voltage stability control scheme for voltage stability enhancement. Based on the utilization of the voltage stability monitoring index based on local information provided by the PMU(Phasor Measurement Unit), the purpose of the plan is to control the system stably in real time. In order to apply the load control scheme, the voltage stability margin is calculated using the data acquired through the PMU installed in each load bus. If the voltage drops below a certain level, load control is performed for each. The effectiveness of the voltage stability control measures is applied to the actual KEPCO system to analyze the effectiveness.

• Journal of the Korean Solar Energy Society
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• v.38 no.4
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• pp.11-31
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• 2018

Nowadays, domestic photovoltaic system market has been expanded and the governmental dissemination policy has been continued. There is only PV system output performance analysis which is called Performance Ratio(PR) analysis. However, there exists many parameters that can affect PV system output. This papers shows the PV system energy performance analysis using meteorological monitoring data. The meteorological monitoring system was installed in the H university and we analyzed the PV system which installed in the H university. We also investigated other three PV systems which located less than 3 kilometers from H university. We evaluated total 4 PV systems through the field survey data, design drawing data and power generation data. Finally, we compared the actual measuring data with the simulation data using PVSYST software.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.8
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• pp.941-950
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• 1999

This paper presents a DSM monitoring methodology that is able to evaluate the impact of DSM programs especially focused on the strategic conservation i.e. the enhancement of end-use energy efficiency. For an effective assessment of DSM programs, it is foremost necessary to examine the market characteristics on the specific end-use appliance according to the customer's adoption of DSM programs. The proposed monitoring methodology contains a diffusion process of high efficient end-uses considering major factors of DSM impact such as, price, reference capacity, forecasted capacity and lifetime of end-use appliances. Case studies show the projection of power reductions and energy savings resulted from DSM monitoring in order to diagnose the current status properly and provide a baseline of DSM policy and analysis.

• Transactions on Electrical and Electronic Materials
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• v.14 no.2
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• pp.71-77
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• 2013

Advanced semiconductor manufacturing technology requires methods to maximize tool efficiency and improve product quality by reducing process variability. Real-time plasma process monitoring and diagnosis have become crucial for fault detection and classification (FDC) and advanced process control (APC). Additional sensors may increase the accuracy of detection of process anomalies, and optical monitoring methods are non-invasive. In this paper, we propose the use of a chromatic data acquisition system for real-time in-situ plasma process monitoring called the Plasma Eyes Chromatic System (PECS). The proposed system was initially tested in a six-inch research tool, and it was then further evaluated for its potential to detect process anomalies in an eight-inch production tool for etching blanket oxide films. Chromatic representation of the PECS output shows a clear correlation with small changes in process parameters, such as RF power, pressure, and gas flow. We also present how the PECS may be adapted as an in-situ plasma arc detector. The proposed system can provide useful indications of a faulty process in a timely and non-invasive manner for successful run-to-run (R2R) control and FDC.

• Journal of IKEEE
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• v.20 no.3
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• pp.299-302
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• 2016

In this paper, we designed the stack monitoring system with improved performance. To block the incoming pulse noise to the amplifier, shield and the power supply impedance are reduced and the power circuit is isolated. The control unit is developed with variable high voltage, adaptive gain, offset and threshold in order to match the scintillation detector characteristic to the apparatus. 300-1500V variable high voltage power circuit is configured applicable to various scintillation detector. Stack monitoring system with improved performance guarantee the efficiency and the reliability by considering the characteristic of various scintillation detector. Developed stack monitoring system is evaluated with certified testing equipment and shows excellent performance with respect to the uncertainty of the sensor test results.

• Journal of Electrical Engineering and Technology
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• v.9 no.5
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• pp.1643-1653
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• 2014

This paper presents the design and implementation of a wind-solar hybrid power system for LED street lighting and an isolated power system. The proposed system consists of photovoltaic modules, a wind generator, a storage system (battery), LED lighting, and the controller, which can manage the power and system operation. This controller has the functions of maximum power point tracking (MPPT) for the wind and solar power, effective charging/discharging for the storage system, LED dimming control for saving energy, and remote data logging for monitoring the performance and maintenance. The proposed system was analyzed in regard to the operation status of the hybrid input power and the battery voltage using a PSIM simulation. In addition, the characteristics of the proposed system's output were analyzed through experimental verification. A prototype was also developed which uses 300[W] of wind power, 200[W] of solar power, 60[W] LED lighting, and a 24[V]/80[Ah] battery. The control system principles and design scheme of the hardware and software are presented.

• Proceedings of the KIEE Conference
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• 1998.07c
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• pp.939-942
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• 1998

This paper presents the process on the construction for the remote distribution pole transformer monitoring system. Especially, this system uses CATV cable as communication media which is located in KEPCO's main distribution line. It has four major components such as sensor for measuring secondary voltage and currents of distribution transformer, RF modem for data modulating/de-modulating, communication media for sending/receiving of data, and pc server for monitoring the results of sensing or computing information. This paper also describes the configuration of these each component's configuration and its functions.

• Proceedings of the KIEE Conference
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• 1998.07c
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• pp.1173-1175
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• 1998

This paper presented the development plan of voltage security on-line monitoring system (VSECOMs). VSECOMs consists of voltage security monitoring system and data management system. VSECOMs has the function of bus voltage watch. voltage stability analysis, and voltage security assessment. EMS data on-line acquisition, PSS/E file conversion, and overall data management. VSECOMs is designed with client/server structure. We will seek stable operation of KEPCO's power system by installation of VSECOMs in EMS of KEPCO.