• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.193-196
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• 2014

Experimantal evaluation of an energy storage device with high rotational speed to store regenerative energy which might be generated during the braking period of the trains is presented. The proposed ESS is small scale model and has 5kW output power, high rotational speed. In general railway trains generate regenerative energy for 10-20 sec when the train brakes and also high traction energy is needed for very short moment (10 sec) when the train increases the traction force. Considering such characteristics of the railway system energy storage device for the railway should have very fast response property. Among the various energy storage devices flywheel energy storage system has the fastest response property, which means that flywheel ESS is the most suitable for the railway system.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.413-415
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• 2001

A railroad vehicle(Light weight electric rail car, Urban railroad, High-speed railroad) need to construct propulsion- system capacity experiment equipment to test performance or to estimate confidence. Experiment equipment in interior have been used Flywheel which is equal to the same inertia as railroad straight moment. But mechanical inertia using flywheel don't change inertia and can't embody traveling-struggle which is similar to actual traveling-struggle. We propose the method to embody electric railroad load system with inertia using electric servo motor in order to get the characteristic of real vehicle load, and confirm this algorithm with simulation and experiment.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1213-1214
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• 2006

본 논문에서는 5 kWh급 초전도 플라이휠 에너지 저장장치(Superconductor Flywheel Energy Storage System : SFES)를 제작하고 시험운전을 통하여 회전 테스트를 수행하였다. 본 연구에서 사용된 초전도 베어링은 저널형 베어링으로써 액체 질소를 순환시켜 초전도체를 냉각시키고 휠을 부양시켜서 전동발전기를 통하여 회전시키게 된다. 액체 질소를 순환하였을 경우 초전도 베어링의 냉각특성을 고찰하였고, 전동 발전기를 이용하여 2000[rpm]까지의 회전 테스트가 수행 되었으며, 전동발전기의 동작 특성 및 회전시 휠의 궤적과 축진동 특성을 테스트 하였다.

• Proceedings of the KIEE Conference
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• 2004.10a
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• pp.3-5
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• 2004

본 연구에서는 고효율, 반영구적인 수명 및 환경친화성으로 인해 효과적인 전력저장장치로 대두되고 있는 플라이휠 에너지 저장(SFES : Super-conductivity Flywheel Energy Storage) 시스템의 구동원으로 적용되는 전동발전시스템에 대한 설계, 제작 및 시험을 수행하였다. 전동발전기는 슬롯리플에 의한 와전류 손실이나 열손실을 고려하여 슬롯리스 Ring-wound형으로 선정하였으며, 전력변환기는 PWM Boost 컨버터를 통해 역률 및 DC 전압 제어 그리고 Full Bridge 인버터를 통해 전동발전기 고속운전 제어를 실현할 수 있는 Topology를 채택하였다.

• The KSFM Journal of Fluid Machinery
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• v.20 no.1
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• pp.48-52
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• 2017

Small-scale motor-generator sets have been used in laboratories for verification of real large wind turbines whose rated power are more than 1 MW. In this paper, a result of designing a small-scale motor-generator system, which is composed of motor, gear box, flywheel, and generator, is presented in the aspect of speed response. Design objective is to make a small-scale motor-generator system have the same time constant and optimal tip speed ratio region as a real MW wind turbine. A small-scale 3.5 kW motor-generator system for emulating response of a 2 MW wind turbine is considered and designed.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.354-355
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• 2018

Flywheel energy storage system (FESS) operates motor or generator by utilizing the stored kinetic energy in the rotating mass. Thus, the FESS can support the frequency control of the power system. However, the FESS is disabled when the rotor speed reaches to its minium value. Thus, the second frequency dip occurs in the power system. This paper proposes the frequency control scheme of FESS based on a variable gain depending on the rotor speed and frequency deviation. The proposed scheme prevents the second frequency dip because the variable gain decreases depending on the stored in the FESS. The performance of the proposed scheme is investigated for the IEEE 14-bus system.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.46-48
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• 1999

This paper treated the design and characteristics of high speed motor/generator with ring wound stator for the flywheel energy storage system. The most important advantages of the ring-wound motor is the slotless stator, i.e. no cogging torque, no space harmonic of air-gap flux density, etc. Because of these advantages, ring wound type motor is suitable to operate at the high speed.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.272-274
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• 1998

This paper treated the design and performance test of high speed motor/generator used in the flywheel energy storage system. The unique characteristics of the motor in this paper is the it doesn't contain any magnetic material. The field system was constructed by using Halbach array that generates the magnetic field with the permanent magnet only. The armature was also composed of plastic bobbin and winding. This paper shows the design results have a good agreement with the experimental results.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.2163-2166
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• 2004

For designing high Tc superconductor proceeding bearing(HTSJB) which is used on a flywheel energy storage system which requests the free of the bearing loss caused by the friction, it is necessary to understand the basic characteristics of the classical superconductor proceeding bearing because the mechanical characteristics of the HTSJB are identified by the magnetic relationships between the permanent magnet(PM) and the high Tc superconductor(HTS). In this paper, using the method, frozen image model, the force problems between the PM and the HTS were solved and then the dynamic characteristics of the rotor inside of the HTSJB can be expected in advance by using the basic characteristics between the PM and the HTS. The coefficient of friction of the HTSJB was measured in the vacuum environment. From the results, the mechanical characteristics of HTSJB can be identified using the numerical models.

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.3
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• pp.361-366
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• 2013

This paper presents the effect on application of the flywheel energy storage system (FESS) for load frequency control (LFC) of an interconnected 2 area power system. To do this, the control characteristics with the FESS were compared with that of the conventional governor controller. The controller for the FESS control and the governor control used a PID type controller. Both the FESS PID controller and the governor PID controller using genetic algorithm (GA) were designed to optimize the PID parameters. The frequency and generation output characteristics with the only FESS controller and with the only conventional governor controller were compared. To verify robust performance of the FESS controller, the computer simulations were performed under various disturbances. The simulation results showed that the FESS controller provided better dynamic responses in comparison with the conventional governor controller.