• 조명전기설비학회논문지
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• 제24권8호
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• pp.70-77
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• 2010

본 논문에서는 차세대 고속철도에 적용하기 위한 IPMSM 견인시스템의 전류 및 속도제어기를 설계한다. 차세대 고속철도는 동력분산식 시스템으로 개발되며 고효율화를 위해 IPMSM 적용 견인전동기를 사용하였고 전동기 제어를 위해 벡터제어 기법을 사용한다. 이 때 벡터제어 루프내 제어기 이득 값은 IPMSM의 과도특성과 속도제어 능력에 영향을 미치기 때문에 알맞은 이득 설계가 요구된다. 본 논문에서는 IPMSM 적용 차세대 고속철도용 견인전동기의 제어기를 설계하여 Matlab/Simulink 기반 모의시험 프로그램을 개발하고 이를 이용한 시험 결과를 분석하였다.

• Journal of Power Electronics
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• 제6권3호
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• pp.235-244
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• 2006

Recently, speed sensorless vector control for synchronous reluctance motors (SYRMs) has deserved attention because of its advantages. Although rotor angle calculation using flux estimation is a straightforward approach, the DC offset can cause an increasing pure integrator error in this estimator. In addition, this method is affected by parameter fluctuation. In this paper, to control the motor at the low speed region, a modified programmable cascaded low pass filter (MPCPLF) with sensorless online parameter identification based on a block pulse function is proposed. The use of the MPCLPF is suggested because in programmable, cascade low pass filters (PCLPF), which previously have been applied to induction motors, the drift increases vastly wl)en motor speed decreases. Parameter identification is also used because it does not depend on estimation accuracy and can solve parameter fluctuation effects. Thus, sensorless speed control in the low speed region is possible. The experimental system includes a PC-based control with real time Linux and an ALTERA Complex Programmable Logic Device (CPLD), to acquire data from sensors and to send commands to the system. The experimental results show the proposed method performs well, speed and angle estimation are correct. Also, parameter identification and sensorless vector control are achieved at low speed, as well as, as at high speed.

• 전기학회논문지
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• 제66권2호
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• pp.453-458
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• 2017

R-Bar (Overhead Rigid Conductor system) has been lately used for the speed of over 200km/h in Europe, while it has been developed and used for the max. speed of 120km/h in Korea. Because R-Bar has advantages of reduction of tunnel cross sectional area and maintenance, its development for more high-speed is urgent in Korea having many mountain area. Therefore a sensitivity analysis of design parameters for the speed-up of R-Bar has performed in this study. For the analysis, we have developed a program for the prediction of dynamic characteristics between a pantograph and R-Bar. The program was evaluated with the actual test result and a current collection performance according to the parameters such as a distance between brackets, a stiffness of bracket and of R-Bar rail was predicted with the program.

• 동력기계공학회지
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• 제17권4호
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• pp.64-71
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• 2013

In this paper, finite element method was used for flow and strength analysis of AZ31 magnesium alloy under friction stir welding. The simulations were carried out by SYSWELD s/w, and the modeling of sheet was doned by unigraphics NX3 s/w. Welding variables for analysis were rotating speed and welding speed of tool. Also two-way factorial design method was applied to confirm the effect of welding variables on maximum temperature and stress of material used. From these results, the increaser welding speed of tool the decreaser maximum temperature, but the increaser maximum stress. Also the increaser rotating speed of tool the increaser maximum temperature, but the decreaser maximum stress. In addition the increaser welding speed of tool and the decreaser rotating speed of tool, the narrower heat effect zone. Finally rotating speed of tool influenced on maximum temperature more than welding speed of tool, and welding speed of tool influenced on maximum stress more than rotating speed of tool from the variance analysis.

• Wind and Structures
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• 제32권5호
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• pp.487-499
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• 2021

The wind-blown sand effect on the high-speed train is investigated. Unsteady RANS equation and the SST k-ω turbulent model coupled with the discrete phase model (DPM) are utilized to simulate the two-phase of air-sand. Sand impact force is calculated based on the Hertzian impact theory. The different cases, including various wind velocity, train speed, sand particle diameter, were simulated. The train's flow field characteristics and the sand impact force were analyzed. The results show that the sand environment makes the pressure increase under different wind velocity and train speed situations. Sand impact force increases with the increasing train speed and sand particle diameter under the same particle mass flow rate. The train aerodynamic force connected with sand impact force when the train running in the wind-sand environment were compared with the aerodynamic force when the train running in the pure wind environment. The results show that the head car longitudinal force increase with wind speed increasing. When the crosswind speed is larger than 35m/s, the effect of the wind- sand environment on the train increases obviously. The longitudinal force of head car increases 23% and lateral force of tail increases 12% comparing to the pure wind environment. The sand concentration in air is the most important factor which influences the sand impact force on the train.

• International journal of advanced smart convergence
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• 제13권1호
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• pp.185-193
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• 2024

This study aimed to investigate the immediate physiological responses, including heart rate, blood pressure, and rate pressure product (RPP), following squat exercises performed at three water depths (ground, knee depth, waist depth) and two speed conditions (60bpm speed, Max speed). The participants consisted of 10 men in their 20s with over 6 months of resistance exercise experience. For the 60bpm speed squats, participants performed 30 repetitions in 1 minute at a rate of 2 seconds per repetition, while for Max speed squats, they performed at Max speed without a set limit on the number of repetitions for 1 minute. All experiments were conducted with a random assignment. The study results showed that immediately after the aquatic squat exercise, the average heart rate, blood pressure, and cardiac load were higher in the order of knee depth, ground level, and waist depth at both 60bpm speed and Max Speed. At 60bpm speed, the heart rate was higher in the order of ground level, knee depth, and waist depth. Overall, exercise in an aquatic environment was considered to impose relatively lower physical burden compared to land-based exercise. Therefore, it is suggested that depending on individual fitness levels and exercise goals, appropriately combining aquatic exercise, which imposes lower immediate physiological burden, and land-based exercise may lead to safer and more effective exercise methods.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.163-165
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• 2006

This paper presents a implementation of speed sensorless vector control algorithm of induction motor using MATLAB/SIMULINK amd dSPACE DSl104 R&D board. The estimation of rotor flux linkage and rotor speed is carried out using model reference adaptive system(MRAS) method. Estimated rotor speed is used to speed controller of induction motor. Simulation results are presented to confirm speed sensorless vector control algorithm.

• Journal of information and communication convergence engineering
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• 제8권1호
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• pp.29-34
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• 2010

Wind speed and wind direction are usually taken using two parameters: wind speed and wind direction. This paper studies the average wind speed and direction calculation methods. The paper first introduces to basic wind's knowledge, and then presents several methods in calculating average wind speed and direction. Lastly some graphs are plotted base on these computational methods and the implementation of these methods in an actual buoy system.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.876-881
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• 2008

When biped robots speed up to run and reduce speed to walk after running, it needs stable speed translation. This paper proposed simple speed translation using the modified LIPM (Linear Inverted Pendulum Mode). We can change stride and period time of a biped robot in some bounded sets with this propose algorithm. This method is simple and effective in simulation.

• 산업기술연구
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• 제20권B호
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• pp.175-182
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• 2000

In this paper, a novel speed control strategy using an acceleration feedforward compensation by the estimation of the system inertia is proposed. With the proposed method, the enhanced speed control performance can be achieved and the speed response against the disturbance torque can be improved for the vector-controller induction motor drive systems in which the bandwidth of the speed controller cannot be made large enough. The experimental results confirm the validity of the proposed strategy.