• Proceedings of the KSR Conference
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• 2008.06a
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• pp.428-432
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• 2008

The next Korean high speed train development project is started. In testing stage of this project, the 400km/h maximum speed test will be conducted. In Korean railway infrastructure conditions the 400km/h seems to be a critical speed especially in the aspect of the overhead contact lines. The current collection performance of the 400km/h which is predicted by dynamic interaction simulation are described in this paper. To discuss the permissible criteria of contact forces, displacements and percentage contact loss, the French 575km/h current collection conditions are simulated. Furthermore, review of the simulation results of the Korean 400km/h current collection conditions is conducted through comparison with that of the French 575km/h.

• Proceedings of the KSR Conference
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• 1998.05a
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• pp.349-358
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• 1998

This study was carried out about the design and the performance study of propulsion system for Korean High Speed Train of maximum operating speed of 350km/h. The propulsion system was studied to two parts the formation of power transmission and the performance of traction system base on Korean-TGV. For maximum operating speed of 350km/h at Seoul-Pusan high speed line, the power of train should be have the remaining acceleration of 0.058m/s/s and the slopeability of 6%o. This performance study of propulsion system would be continued for defining of adhesion factor, friction factor and aerodynamic factor assumed to analysis and simulation.

• Proceedings of the KSR Conference
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• 2009.05b
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• pp.201-206
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• 2009

In the testing stage of HEMU-400X(next Korean high speed train) developing project, maximum speed(400km/h) tests will be conducted. On present and near future conditions of the overhead contact lines, 400km/h is over the design speed criteria. The predictions of current collection performance including the percentage loss of contact(arcs level) parameter through dynamic interaction simulation of HEMU-400X maximum speed test run are described in this paper. Various simulations are conducted at the condition of two different contact wire tensions to draw the proper contact wire increasing values in the 400km/h test line under the available contact wire tension supporting condition of that line.

• Journal of information and communication convergence engineering
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• v.19 no.1
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• pp.61-66
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• 2021

An underwater remotely operated vehicle (ROV) has been implemented. It can inspect foreign substances through a CCD camera while the ROV is running in water. The maximum thrust of the ROV's running thruster is 139.3 N, allowing the ROV to move forward and backward at a running speed of 1.03 m/s underwater. The structural strength of the guard frame was analyzed when the ROV collided with a wall while traveling at a speed of 1.03 m/s underwater, and found to be safe. The maximum running speed of the ROV is 1.08 m/s and the working speed is 0.2 m/s in a 5.8-m deep-water wave pool, which satisfies the target performance. As the ROV traveled underwater at a speed of 0.2 m/s, the inspection camera was able to read characters that were 3 mm in width at a depth of 1.5 m, which meant it could sufficiently identify foreign objects in the water.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.2
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• pp.231-236
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• 2012

This paper presents the MPPT(Maximum Power Point Tracking)control method of the PMSG wind generation system using the turbine model with a squirrel cage induction motor. The torque of squirrel cage induction turbine model is controlled by mathematization of speed characteristics of real blade. In this paper, maintenance and cost issues into consideration, except for previous method using information of the velocity of the wind speed sensor, the algorithm is presented. The algorithm is controlled by tracking the optimal point, the generator speed and maximum grid power. The vector controls of the generator side converter and the grid side converter are controlled respectively to obtain maximum torque and regulate unity power factor. With Psim simulations and experiments, the efficiency of squirrel cage induction turbine model and the validity of control algorithm are verified.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.73-77
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• 2003

This paper presents a high-speed algorithmic analog-to-digital converter (ADC), which is based on gray coding. The realization method makes use of a two-input maximum circuit to provide a high-speed operation and a low-distortion in the transfer characteristic. The proposed ADC based on the CMOS integrated circuit technique is simple and suitable for implementing a highresolution ADC. The performances of the proposed circuit were studied using the PSPICE analog simulation program. The simulation-results verifying the circuit performances are agreed with the expected values.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.650-655
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• 2001

Wind speeds can vary rapidly and wind turbines cannot easily follow these variations because of their inertia and aerodynamic characteristics. For maximum energy extraction. the turbine blades should operate at their optimum tip speed ratio, but with rapid changes in wind speed. this is usually not possible. To improve the energy extraction from turbulent wind, it is necessary to establish an effective measure of the high frequency component of the wind. and then to use this measure to optimise the operation of the turbine controller for maximum energy extraction. This paper presents an approach for combining readings from three anemometers into a composite wind speed measurement. and using this signal to control the operation of a permanent magnet generator to achieve maximum energy extraction. The method combines simulation and experimental investigations into a heuristic algorithm. and demonstrates its effectiveness with field trials.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.8
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• pp.27-34
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• 2012

This paper proposes variable incremental conductance(IC) algorithm for maximum power point tracking(MPPT) control of photovoltaic. The conventional perturbation & observation(PO) and IC MPPT control algorithm generally uses fixed step size. A small step size reduces a tracking error in the steady state but slows a tracking speed in the transient state. Also, a large step size is fast a tracking speed but increases a tracking error. Therefore, this paper proposes variable IC MPPT algorithm that adjust automatically step size according to operating conditions. To improve a tracking speed and accuracy, when operating point is far from the maximum power point(MPP), the step size uses maximum value and when a operating point is near from the MPP, the step size uses variable step size that adjust according to slope of P-V curve. The validity of MPPT algorithm proposed in this paper prove through compare with conventional PO and IC MPPT algorithm.

• Tribology and Lubricants
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• v.3 no.2
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• pp.68-71
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• 1987

This paper deals with some thermal Characteristics of journal bearing such as the behaviour of the maximum bearing temperature, the lubricant's carry-over in the inlet region and so on. Temperatures of the bearing and the lubricants being supplied and discharged were measured along with shaft speed and bearing load. The results showed that with the increase of the Shaft speed, the maximum temperature rose at any shaft speed at a defferent rate of change defending on the flow regime of the lubricant film. And the lower eccentricity ratio is the more lubricant's carry-over occur. Additionally it was partially proved that the oil discharge temperature and the maximum temperature changed in quite different each other.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.54 no.4
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• pp.185-191
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• 2005

In this paper, a new approach for the Synchronous Reluctance Motor control which ensures producing Maximum Torque per Ampere(MTPA) over the entire field weakening region is presented. In addition, This paper presents a speed sensorless control scheme of SynRM using artificial neural network. Also, by adjusting the base speed for the field weakening operation according to the flux level, the current and voltage limit, the smooth and precise transition into the field weakening operation can be achieved. The proposed scheme is verified validity through simulation.