• 유체기계공업학회:학술대회논문집
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• 1999.12a
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• pp.291-300
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• 1999

Currently under development is an airborne auxiliary power unit with 100 Kw equivalent power, which is composed of a centrifugal compressor, a reverse annular combustor, and a radial turbine. Air-foil bearings are used in this power unit to eliminate the oil supplying system, which can reduce the system complexity and weight. The high speed generator is adopted as an electric power generation and engine starting system, which can also eliminate the reduction gear system. Not only electric power but also pneumatic power is provided by bleeding the compressed air This power unit is aimed for the multi-purpose use such as a primary power unit In the army weapon system, an auxiliary power and environmental control unit in a next-generation tank, and a smoke generating unit.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.563-566
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• 2003

We have designed the power control unit which belongs to the power cabinet and controls the power supplied to Control Rod Drive Mechanism(CRDM) as a digital system based on Digital Signal Processor(DSP). The power control unit dualized as the form of Master/Slave has had its increased reality. The Central Process Unit(CPU) board of a power control unit possesses two Digital Signal Processors(DSPs) of the control DSP for performing the tasks of power control and system monitoring and the communication of the Control DSP and the Communication DSP. To accomplish the functions requested in the power control unit effectively, we have installed Field Programmable Gate Arrays(FPGAS) on the CPU board and have FPGAs perform the memory mapping, the generation of each chip selection signal, the giving and receiving of the signals between the power controllers dualized, the fault detection and the generation of the firing signals.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.333-335
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• 2008

전력의 안정적 공급 및 신뢰도 확보를 위해 설비에 대한 디지털화가 계속 진행되고 있으며, 또한 이상 진단 시스템도 계속 진보되고 있다. 이에 (주)효성에서는 변압기 진단을 위한 센서 및 IED가 포함된 지능형 변압기(Intelligent Power Transformer)용 Local Unit을 개발하였다. 본 논문은 (주)효성에서 개발한 Local Unit 의 HMI에 대해 기술하였다.

• International Journal of Railway
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• v.8 no.1
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• pp.10-14
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• 2015

Due to the characteristics of the vehicle structure, the magnetic levitation train has a confined bottom space thus a study on miniaturization and weight reduction of auxiliary power unit is essential. This auxiliary power unit is an essential device used for illumination, air conditioning, heating and air brake equipment excluding the motor. The previous auxiliary power unit for magnetic levitation train has used the hard switching having a high switching frequency with heavy loss in order to reduce the size of filter reactor and transformer but the reduction in volume was not significant. In this paper, by reducing the loss, reducing the size of the cooling unit and by increasing the switching frequency using the soft switching of resonant converter, it has miniaturized and reduced the weight of filter reactor and transformer which occupy significant space in the auxiliary power unit. This study has verified the performance of 50KVA grade prototype through simulated interpretation and analysis, and compared the size and weight of auxiliary power unit of the previous magnetic levitation train.

• Journal of Electrical Engineering and Technology
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• v.11 no.2
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• pp.353-360
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• 2016

Series hybrid electric vehicles (SHEVs) having multiple power sources such as an engine- generator (EnGen), a battery, and an ultra-capacitor require a power control unit with high power density and reliable control operation. However, manufacturing using separate individual power converters has the disadvantage of low power density and requires a large number of power and signal cable wires. It is also difficult to implement the optimal power distribution and fault management algorithm because of the communication delay between the units. In order to address these concerns, this approach presents a design methodology and a power control algorithm of an integrated power converter for the SHEVs powered by multiple power sources. In this work, the design methodology of the integrated power control unit (IPCU) is firstly elaborately described, and then efficient and reliable power distribution algorithms are proposed. The design works are verified with product-level and vehicle-level performance experiments on a 10-ton SHEV.

• Nuclear Engineering and Technology
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• v.50 no.8
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• pp.1234-1245
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• 2018

The risk of multi-unit nuclear power plants (NPPs) at a site has received considerable critical attention recently. However, current probabilistic safety assessment (PSA) procedures and computer code do not support multi-unit PSA because the traditional PSA structure is mostly used for the quantification of single-unit NPP risk. In this study, the main purpose is to develop a multi-unit Level 2 PSA method and apply it to full-power operating six-unit OPR1000. Multi-unit Level 2 PSA method consists of three steps: (1) development of single-unit Level 2 PSA; (2) extracting the mapping data from plant damage state to source term category; and (3) combining multi-unit Level 1 PSA results and mapping fractions. By applying developed multi-unit Level 2 PSA method into six-unit OPR1000, site containment failure probabilities in case of loss of ultimate heat sink, loss of off-site power, tsunami, and seismic event were quantified.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.950-954
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• 1998

This paper describes a development of traction unit for 2-motor driven electric vehicle (EV). The traction unit is consisted with an interior permanent magnet synchronous motor (IPMSM), a reduction gear and an inverter for electric vehicle that is driven by 2 motors without differential gear. For traction unit, prototype IPMSM and inverter have been developed. The IPMSM was designed by CAD program that was developed with both equivalent circuit method and FEM. Also the inverter was developed to drive 2 motors with 6 legs IGBT switches in a control board. The vector control algorithm was implemented with maximum torque control method in the constant torque region and field weakening control method in the constant power region considering inverter capacity. To verify that the traction unit is more high efficiency and has more high power density than a traction unit with induction motor with the same power, we would like to show the results about the design and analysis of the IPMSM and the experiment results about the traction unit.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1654-1660
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• 2011

The korea Electric Railway feeder voltage is DC 1500V and AC 250000V. The auxiliary power supply of the vehicle auxiliary power units for domestic electrical feed has been developed with domestic technology hyeonchae mounted station, and domestic uses, such as voltage, have been exported to other countries. However, do not use at domestic that can be used for DC 3000V voltage auxiliary power unit does not develop, vehicle exports global. This has already been replaced by imported products from other nations is a real situation. Thus, our auxiliary power unit for the DC 3000V was developed, it will be exported to Ukraine. In this paper, We introduced circuit and structure of developed auxiliary power supply unit, and verified the performance with output characteristic of the auxiliary power unit.

• Journal of Power Electronics
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• v.15 no.4
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• pp.951-963
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• 2015

In this paper, a new symmetric multilevel inverter is proposed. A simple structure for the cascaded multilevel inverter topology is also proposed, which produces a high number of levels with the application of few power electronic devices. The symmetric multilevel inverter can generate 2n+1 levels with a reduced number of power switches. The basic unit is composed of a single and double source unit (SDS-unit). The application of this SDS-unit is for reducing the number of power electronic components like insulated gate bipolar transistors, freewheeling diodes, gate driver circuits, dc voltage sources, and blocked voltages by switches. Various new algorithms are recommended to determine the magnitude of dc sources in a cascaded structure. Furthermore, the proposed topology is optimized for different goals. The proposed cascaded structure is compared with other similar topologies. For verifying the performance of the proposed basic symmetric and cascaded structure, results from a computer-based MATLAB/Simulink simulation and from experimental hardware are also discussed.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.347_348
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• 2009

In this paper, we described the integrated monitoring system for low-voltage panel boards. This system consists of three parts, a panel board controller, an integrated monitoring unit and a remote PC. The panel board controller which was made of CT/PT unit, control unit and power supply is able to transmit variable parameter for monitoring and diagnosis of low voltage branch circuits. Also, the integrated monitoring unit was collected monitoring data from panel boards and displayed on the touch panel.