• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.1051-1053
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• 2003

Flywheel Energy Storage System (FESS) consists of a high-speed flywheel with an integral motor/generator suspended on magnetic bearings and in an evacuated housing. Permanent magnet (PM) machines as the FESS motor/generator are a popular choice. since there are no excitation losses which mean substantial increase in the efficiency. In this paper, the basic design and the steady-state performances of a permanent magnet synchronous high speed motor/generator for FESS are presented.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1071-1077
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• 2000

Recently, several attempts have been made to apply high Tc superconductor bearings of thrust type to flywheel energy storage system (FESS) throughout the world. Radial type superconductor bearings, however, have never been tried to the real FESS. KEPRI has developed its own radial type bearings and is now currently applying them to a FESS designed by KIMM, for the first time. In this paper preliminary test results of bearing performance and dynamic behavior of the flywheel rotor system mounted on them are presented. The dynamic properties, i.e, stiffness and damping, of the superconductor bearings were experimentally estimated using the static loading test as well as the impact test. The test revealed that stiffness value of the present superconductor bearings is about 67,700N/m and the damping value 29Ns/m. It was also found out that these bearings have some levitation drift problems due to excessive vibrations encountered while passing through the critical speeds. With recommend backup bearings to limit the vibration amplitudes of the rotor it is predicted that the flywheel rotor will show stable operations in the design speed range.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.86-88
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• 2008

The rotational loss is one of the most important problems for the practical use of the high power Flywheel Energy Storage System (FESS). This rotational loss is divided as the mechanical loss by windage and bearing and iron loss by hysteresis loop and eddy current in the part of the magnetic field. So, In this paper, a double-sided PMSM/G without the iron loss is designed by analytical method of the magnetic field and estimation of the back-EMF constant represented as the design parameter. This design model consists of the double-sided PM rotor with Halbach magnetized any and coreless 3-phase winding stator. The results show that the double-sided PMSM/G without iron loss can be applicable to the high power FESS.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.226-227
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• 2011

본 논문에서는 전력 시스템의 저주파 진동을 효율적으로 억제하기 위하여 기존의 PSS 를 이용하는 방법 대신 FESS를 적용하는 방법을 제시하였다. FESS PID 제어기의 최적 파라미터를 선정하기 위하여 GA를 이용한 방법을 제시하였다. 최적화 파라미터 선정시 사용되는 평가함수를 2가지로 선정하여 선정된 파라미터를 이용하여 FESS PID 제어성능을 평가하였다. 다양한 동작 조건하에 몇 가지 외란이 발생한 경우 비선형 시뮬레이션을 통하여 기존의 PSS를 이용한 방법과 동특성을 비교 고찰하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제37권7호
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• pp.771-777
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• 2013

This paper describes a study of major shipyard's electrical network and simulation of applying flywheel energy storage system on the electrical network at shipyard for shore-power to ships and offshore plants in order to save fuel consumption on engines, mitigate voltage sags, and prevent blackout due to pulsed load and fault, resulting in reduction of air emission into atmosphere. The proposed energy recycling method with FESS (Flywheel Energy Storage System) can be applied for electrical power system design of heavy cranes at shipyards.

• 소음진동
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• 제9권5호
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• pp.891-898
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• 1999

The purpose of Superconducting Magnetic Bearing Flywheel Energy Storage System (SMB-FESS) is to store unused nighttime electricity until it is needed during daytime. An analytical model of the SMB-FESS is necessary to identify the system behavior. At first, we have to model the superconducting magnetic bearing. Modeling the SMB is same as estimating the bearing parameter. The theoretical modal parameter is calculated through the equation of motion and the experimental modal parameter is estimated through the impact testing (modal testing). The bearing parameter is searched by using the non-linear least square method until the theoretical result corresponds to the experimental result. The suggested modeling method is verified by comparing experimental and analytical frequency response function.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.485-490
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• 2004

Flywheel Energy Storage System(FESS) consists of a high speed flywheel with an integral motor/generator suspended on non contact bearings and in an evacuated housing. Permanent magnet machines as the FESS motor/generator are a popular choice, since there are no excitation losses which means substantial increase in the efficiency. In this paper, the structural design method of rotor retainer for a high speed motor/generator are presented.

• Progress in Superconductivity
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• 제13권1호
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• pp.40-46
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• 2011

A superconductor flywheel energy storage system (SFES) is an electro-mechanical battery which transforms electrical energy into mechanical energy for storage, and vice versa. A 10 kWh class flywheel energy storage system (FESS) has been developed to evaluate the feasibility of a 35 kWh class SFES with a flywheel $I_p/I_t$ ratio larger than 1. The 10 kWh class FESS is composed of a main frame, a composite flywheel, active magnetic dampers (AMDs), a permanent magnet bearing, and a motor/generator. The flywheel of the FESS rotates at a very high speed to store energy, while being levitated by a permanent magnetic bearing and a pair of thrust AMDs. The 10 kWh class flywheel is mainly composed of a composite rotor assembly, where most of the energy is stored, two radial and two thrust AMD rotors, which dissipate vibration at critical speeds, a permanent magnet rotor, which supports most of the flywheel weight, a motor rotor, which spins the flywheel, and a central hollow shaft, where the parts are assembled and aligned to. The stators of each of the main components are assembled on to housings, which are assembled and aligned to the main frame. Many factors have been considered while designing each part of the flywheel, stator and frame. In this study, a 10 kWh class flywheel energy storage system has been designed and constructed for test operation.

• 한국가금학회지
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• 제35권1호
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• pp.21-27
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• 2008

본 연구는 산란노계 사료 내 광물질 강화제의 추가적인 공급이 산란노계의 생산성, 계란 품질 및 혈청 내 칼슘, 인 농도에 미치는 영향에 대하여 알아보기 위해 수행하였다. 사양시험은 72주령 Hy-line Brown 240수를 공시하여 4주간 실시하였다. 1) CON(basal diet), 2) ESS1(basal diet + Egg shell strengthener 0.1%), 3) ESS2(basal diet + Egg shell strengthener 0.2%) 및 4) FESS(basal diet + Fe egg shell strengthener 0.2%)로 4개 처리를 하여 처리당 5반복, 반복당 12수씩 완전 임의 배치하였다. 전체 시험 기간 동안 산란율은 대조구 및 ESS2 처리구가 ESS1 처리구와 비교하여 유의적으로 높게 나타났으며(P<0.05), 난각 강도 및 종료시의 난각 두께는 ESS2 처리구가 대조구 및 FESS 처리구보다 유의적으로 높게 나타났다(P<0.05). 계란 품질에서 난황색은 ESS1 처리구가 다른 처리구와 비교하여 유의적으로 가장 낮게 나타났으며(P<0.05), 호우유닛은 ESS1 처리구 및 FESS 처리구가 대조구와 비교하여 유의적으로 낮았다(P<0.05). 미네랄 및 비타민 강화제의 첨가는 혈청 내 Ca 및 P 함량과 난각색에 영향을 미치지 못했다. 결론적으로, 산란노계 사료에 0.2%의 미네랄 및 비타민 강화제를 첨가한 ESS2 처리구는 난각 강도와 두께가 개선되는 효과를 나타내었다.

• 한국산학기술학회논문지
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• 제17권12호
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• pp.678-685
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• 2016

현재까지 연하 장애의 검사법으로 Gold standard 한 검사법은 영상의학과의 투시 장비를 이용한 삼킴 검사법이었다. 그러나 근래에 들어서면서 내시경을 이용한 검사법이 이용되면서 진단에 많은 도움을 주었다. 따라서 본 연구에서는 VFSS와 FEES를 동시에 수행함으로 FEES의 안정성과 유용성을 평가했습니다. 본 연구는 2013년 12월부터 2014년 3월까지 연하 곤란의 진단 또는 평가를 위해 VFSS와 FEES 두 가지 검사를 모두 시행한 130명을 대상으로 하였고, 장비는 VFSS(FELAVISION, SHIMADZU), FESS(EVIU LUCERA CV-260SL, OLYMPUS)을 사용하였다. Logemann의 protocal을 일부 변형하여 2.5 ml, 5 ml, 10 ml의 바륨 희석액, 바륨을 희석한 요거트, 바륨을 희석한 죽, 바륨을 희석한 밥을 준비하여 취식하게 한 후 pharyngeal residue, penetration, aspiration 등을 확인하였다. FULL HD동영상을 사용한 VFFS 검사에서와 FEES 검사에서는 총130명의 환자에서 36명이 두 검사 모두에서 Aspiration이 관찰되었다. 이중 VFFS 에서는 36명이 Aspiration이 발견되었고 FESS에서는 5명이 증가한 41명에서 Aspiration이 관찰되었다. 본 연구에서는 FEES 의 검사법이 연하곤란의 진단에는 더욱 민감하게 검출 되었으나 이 두 가지 검사법은 상호 보완적이기 때문에 보다 숙련된 내시경조작법과 정확한 투시검사가 병행될 때 진단적 가치는 훨씬 향상될 것이다.