• The KSFM Journal of Fluid Machinery
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• v.16 no.6
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• pp.5-11
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• 2013

Torque control methods of wind turbine are mainly classified into two methods: torque-mode and speed-mode methods. The traditional torque-mode method, in which generator torque proportional to square of generator speed is determined, has been chosen in many wind turbines but its response is slower as they are larger in multi-MW size. Torque control methods based on both speed-mode and torque-mode can be used to make response of wind turbine faster. In this paper, two torque control methods based on the traditional torque-mode method are applied to a 2.75 MW wind turbine. It is shown through some simulation results for real turbulence wind speeds that torque control method based on torque-mode has the merit of reducing fluctuations of generated power than PI controller based on speed-mode.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.2
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• pp.44-51
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• 2014

This paper describes system definition of the extended range EV and presents cruising strategy of EV mode and ER mode. Also high voltage battery strategic SOC could be indicated and compared depends on various generator working cycles. A C-segment SUV has been produced and carried out cruising test in order to validate on highway, city and hill climbing road. This paper shows advantages and disadvantages of SOC variation on each road environments and presents the strategies as the cruising test results. On the basis of the test result, this paper suggests future works and research directions for strategy of battery management to extended range EV.

• Composites Research
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• v.36 no.3
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• pp.224-229
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• 2023

Due to the increasing demand for wearable devices and miniaturization of various electronic devices, the trend of nanofabrication in IT devices is underway. In order to overcome the limitations of battery size and capacity, there has been a lot of research interest in energy harvesting technology, also known as triboelectric nanogenerator. AAO(Anodic Aluminum oxide) coated with fluoride is a structure that includes an anode layer with high properties in the triboelectric series, an dielectric layer that helps transfer the triboelectrically generated charges to the electrode without loss, and the electrode. For these reasons, AAO has been a lot of research on its application to frictional energy harvesting nanogenerators. In this work, we analyzed the correlation of AAO between the surface morphology and thickness of the insulating layer by utilizing aluminum oxide, which is advantageous for the application of triboelectric nanogenerators, and adjusting the thickness of the insulating layer.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.3
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• pp.32-39
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• 2003

The output voltage of synchronous generator is regulated constantly by field current control in excitation system High frequency PWM converter (current control mode buck converter) type excitation systam fer synchronous generator is able to control exciter current when the load change happened. This paper deals with the design and evaluation of the excitation system for a synchronous generator to improve the steady state and transient stability. The simulation and experimental results show that the proposed excitation system is able to improve the response time by the DVR(digital voltage regulator) of 50[kW] synchronous generator.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.668-669
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• 2016

The retarder as a hydraulic brake system in order to assist a service brakes in commercial vehicle is operated by automatic and manual mode due to driver. Braking energy by retarder operation is transmitted to the engine radiator of vehicle cooling system, passing through the retarder oil heat exchanger. At this moment, the retarder ECU performs the function that is controlled a braking torque with consideration for automatic and manual mode, temperature of retarder oil/water, engine coolant temperature, vehicle speed, and etc. In this paper, it deals with the design of retarder control logic and the results of retarder braking performance test regarding a cooling system of retarder and vehicle.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.350-355
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• 2003

This paper presents results of vibration analysis of a end-winding of large generator for fossil power plant. A finite element analysis using a commercial S/W is performed to calculate alternating electromagnetic forces, mainly of 120㎐ in 60㎐ machines, acting on the end-winding, and then to calculate forced response of the end-winding under electromagnetic forces. Also, this paper presents analytical and experimental modal analysis results of generator end-winding to validate FE model. We calculated forced response of end-winding on 120㎐, double rotating frequency. These results will be used to evaluate structural reliability of end-winding and applied to update model.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.300-302
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• 2003

본 연구에서는 발전기에 적용된 전력계통안정화장치(Power System Stabilizer)의 적용사례를 분석한다. 전력계통안정화장치에 적용된 알고리즘은 Lead-Lag 제어기가 있고, 현대 제어이론에 바탕을 둔 LQR, LQG, $H_{\infty}$, 슬라이딩모드 제어기, 비선형궤환제어기가 있다. 그 외에 퍼지제어기, 뉴럴 제어기, 진화연산제어기등이 있다. 이중에 전력계통안정화장치의 제어알고리즘에 대하여 대표적인 사례를 파악하고져 한다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.826-831
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• 2001

Electromagnetic forces generate vibrations in the end-winding of large generators. A finite element analysis using a commercial S/W is performed to calculate electromagnetic force of end-winding in two pole generator for 500 MW fossil power plant. Also, this paper presents analytical and experimental modal analysis results of generator end- winding. Using validated FE model, 3D electromagnetic model which computes the forces on the end-winding is coupled with a 3D mechanical model which calculates the dynamic displacement and stress under electromagnetic forces. These results will be used to evaluate reliability of end-winding and applied to update model.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.9
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• pp.801-805
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• 2016

In this paper, engine clutch engagement shock is analyzed during the mode change of plug-in hybrid electric vehicles. Multi-driving mode includes the EV (electric vehicle) mode, HEV (hybrid electric vehicle) mode, and engine operating mode. Depending on the mode change, the engine clutch is either engaged or disengaged. The magnitude of shock during clutch engagement is very important because it impacts vehicle acceleration and clutch synchronization speed, which affects ride comfort substantially. The performance simulator of plug-in hybrid electric vehicles was developed using MATLAB/Simulink. The simulation results show that the mode change control algorithm is necessary for minimizing shock during clutch engagement.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.4
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• pp.412-417
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• 2015

The IMO MEPC has been increasingly strengthening the emission standard for marine environment protection. In particular, nitrogen oxide (NOx) emissions of all ocean-going ships built from 2016 will be required to comply with the Tier-III regulation. In this study, a vanadia based SCR (Selective Catalytic Reduction) system developed for ship application was installed on a diesel engine for power generation of the training ship T/S SAENURI in Mokpo National Maritime University. For the present study, the exhaust pipeline of the generator diesel engine was modified to fit the urea SCR system. This study investigated the NOx reduction performance according to the two kind of injection method of urea solution (40%): Auto mode through the PLC (Programable Logic Control) and Manual mode. We were able to find the ammonia slip conditions when in manual mode method. So, the optimal urea injection quantity can be controlled at each engine load (25, 35, 50%) condition. It was achieved 80% reduction on nitrogen oxide. Furthermore, we found that the NOx reduction performance was better with the load up-down (while down to 25% from 50%) than the load down-up (while up to 50% from 25%) test.