• Proceedings of the KIPE Conference
• /
• 2016.11a
• /
• pp.204-205
• /
• 2016

Human power is not dependent on other energy sources, but rather is a source of power for ourselves. Human power, the cleanest energy in the world, can be our future. Therefore, we should be interested in sustainable alternative energy. This paper solves the uneven power generation by utilizing the energy storage capability of the flywheel. Therefore, it improved the efficiency by 5% compared to the existing generation method. DC generators produce power at variable speed operation. The constant voltage was generated from the DC-DC converter to the duty ratio control. Therefore, the charging efficiency is improved by 5% by the constant voltage charging of the battery. And it can suppress the decrease of the output due to the circulation current due to the deviation of the output voltage in parallel operation of the pedal generator.

• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.226-227
• /
• 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.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.4 no.2
• /
• pp.215-222
• /
• 1999

Integrating energy storage into electlic power system has long been recognized as a way to maximize a utility's g generation and transmission capacity, Electlic power can be stored during off-peak periods and then recovered during p peak conditions to offset the need for larger generation and transmission capacity, Currently large-scale SMES for the p purpose of energystorage which can be also se$\pi$ed by battery storage or flywheel system has been developed, and near f future it will be integrated into power grids, This paper presents an investment analysis on large-scale SMES which c can determine its optimal size in power systems, In operation model. least generation cost for energy storage in SMES a and its mar밍nal capacity cost can be calculated using the discreteness of probability distribution for power availability I Investment decisions are made by the maximum p디nciple and the case study shows the optimal operation and realistic i information on the proper size of large-scale SMES in power systems.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.707-708
• /
• 2008

본 논문에서는 초전도 플라이휠 에너지 저장장치 (Superconductor Flywheel Energy Storage System : SFES)의 에너지 변환을 위해 사용된 영구 자석형 전동 발전기(Permanent Magnet Synchronous Motor/Generator : PMSM/G)가 SFES의 에너지 저장효율에 미치는 영향을 평가하였다. SFES 시스템은 YBCO 벌크 초전도체를 이용한 저어널 타입(journal type)의 초전도 베어링을 사용하였으며, 슬롯리스 형 PMSM/G를 사용하였다. PMSM/G의 고정자 코어, 누설 자속 및 감겨진 코일에 의한 저장 에너지 손실을 측정하였다. 사용된 코어의 크기, 누설자속, 및 코일의 적절한 선정을 통하여 저장된 에너지의 손실을 상당히 줄일 수 있음을 확인하였다. 또한 영구자석과 코어가 동시에 회전하는 회전 코어형 전동발전기를 적용하여 에너지 손실을 매우 감소시킬 수 있음을 확인하였다.

• Tribology and Lubricants
• /
• v.23 no.6
• /
• pp.283-287
• /
• 2007

Permanent-magnet (PM) passive bearings use the repulsive forces between the rotor and the stator magnets for the bearing function. It is desirable that the stiffness of the bearing is maximized with the given volume of the magnet. The stiffness is affected by the magnet strength, the number of layers, and the magnetization patterns. Previously, finite-element method (FEM) has been used to maximize the stiffness of the bearing. In this paper, we used the equivalent current sheet method to calculate the stiffness. The validity of this approach is checked against FEM results. The optimized bearing is applied to a micro flywheel energy storage system.

• Proceedings of the KIEE Conference
• /
• 2008.04c
• /
• pp.86-88
• /
• 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.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.11b
• /
• pp.399-403
• /
• 2002

Squeeze film dampers (SFDs) are designed and analyzed for radial superconducting bearings. The designed SFDs are mounted on the superconductors submerged in liquid nitrogen such that the dampers should supply additional damping to the relatively underdamped superconducting bearing support . Basic theory of SFD assembled with superconductors is introduced. Rotordynamic simulations are provided to support the feasibility of the superconducting bearings mounted on SFDs for a horizontal flywheel energy storage system.

• Proceedings of the KIPE Conference
• /
• 2004.07b
• /
• pp.570-574
• /
• 2004

This paper deals with a novel 3-phase power quality disturbance generator. The proposed generator can be applied to the performance that of custom power devices. Voltage sag, swell, outage unbalance and phase shift are provided by the generator. The control scheme for the disturbance generation is simple, and hardware setup is cost effective compared with conventional scheme. The operating principle of the generator is described and the usefulness verified through simulation with 10kVA power rating.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.11a
• /
• pp.343.2-343
• /
• 2002

Squeeze film dampers(SFDs) are designed and analyzed for radial superconducting bearings. The designed SFDs are mounted on the superconductors submerged in liquid nitrogen such that the dampers should supply additional damping to the relatively underdamped superconducting bearing support. Basic theory of SFD with superconducting bearing are introduced. Rotordynamic simulations are provided to support the feasibility of the superconducting magnetic bearings mounted on SFDs for a horizontal flywheel energy storage system.

• Journal of Electrical Engineering and Technology
• /
• v.8 no.1
• /
• pp.124-129
• /
• 2013

Electro-Mechanical Batteries have important advantages compared with chemical batteries, especially in Low Earth Orbit satellites applications. High speed, slotless, external rotor, brushless DC machines are proposed and used in these systems as Motor/Generator. A simplified analytic design method is given for this type of machines and, the optimization of machine in order to have maximum efficiency and minimum volume and weight are given in this paper. Particle swarm optimization (PSO) is used as the optimization algorithm and the finite element-based simulations are used to confirm the design and optimization process and show less than 6% error in parametric design.