jeong phil Lee

KIT-Kyungnam College of Information & Technology · department of new and renewable electric energy

In this paper, a design problem of the flywheel energy storage system controller using genetic algorithm (GA) is investigated for a frequency control of the wind diesel hybrid power generation system in an isolated power system. In order to select parameters of the FESS controller, two performance indexes are used. We evaluated a frequency control...

This paper presents the effect on application of flywheel energy storage system (FESS) for load frequency control (LFC). Both the FESS PID controller and the governor turbine PID controller using genetic algorithm (GA) were designed. The frequency and generation output characteristics for both the FESS controller and the conventional governor turbi...

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...

The stability of superconductor levitation is depending on the pinning force. However, when an external force such as the earthquake with a high magnitude higher than the pinning force is exerted, the levitated permanent magnet (PM) can become unstable and destroyed. In order to improve the stability of the levitation, a copper plate was inserted i...

In this paper, we assessed the characteristics of the rotational energy loss by drag force according to a size change of the new amorphous stator core used on PMSM/G. The accurate method for measuring rotational energy was presented through the spin down test using superconductor flywheel energy storage system (SFES). The mathematical model for cor...

The recent increase in power demand has been pressuring industries to continuously extend or expand power sources and transmission and transformer systems. On the other hand, the equivalent impedance of power systems is decreasing. Accordingly, the fault current magnitude in power systems is increasing. Because of such developments, and the rising...

This study estimated experimentally the loss distribution caused by magnetic friction in magnetic parts of a superconductor flywheel energy storage system (SFES) to obtain information for the design of high efficiency SFES. Through the spin down experiment using the manufactured vertical shaft type SFES with a journal type superconductor magnetic b...

In this paper, an actuator model of the thrust magnetic bearing for the flywheel energy storage is derived using magnetic circuit theory. And we compared this result with finite element magnetic field analysis result. Based on the actuator model, we made a simulation model of the thrust magnetic bearing system. We showed the closed loop transfer fu...

The ongoing Superconducting Fault Current Limiter(SFCL) development mainly has focused on the application of commercializaton and power system through combining with normal-conducting device, moving away from current-limiting method, which is solely dependant on the existing superconductor. Compared to the structural development above, on the other...

A superconductor flywheel energy storage system (SFES) is mainly used as an electro-mechanical battery which transforms electrical energy into mechanical energy and vice versa. Many aspects of the dynamic behavior of flywheel rotors still need to be examined closely, and the rotors require a high capacity supporting system such as high temperature...

The yttrium-barium-copper-oxide (YBCO) coated conductor, which supplement the fault of the existing superconducting current-limit materials YBCO thin film, bismuth-strontium-calcium-copper-oxide(BSCCO) wire and bulk, has been improved its mechanical weakness and has high index; hence, after quench YBCO coated conductor could limit the fault current...

In this paper, the relative stability of magnetic bearing system for the flywheel energy storage is evaluated using both simulation and experimental analysis. We make the simulation model for the magnetic bearing flywheel system using the rigid body shaft model. According to international standard ISO 14839-3, We experimentally analyzed the relativ...

In high speed applications, the slotless permanent magnet motors appear an attractive solution, being almost intensitive to magneto-motive force harmonics and to pulse width modulation(PWM) current ripple and exhibiting lower stator iron losses and rotor losses (significant with square wave current control). In this paper, performance characteristi...

Torque is very essential for performance evaluation of electric machines because it is directly connected with power loss for dynamic characteristics. To evaluate dynamic performance, torque with harmonic component according to time is introduced. Particularly, eddy current loss is significantly increased at high speed, so it is difficult to expres...

YBCO bulks with fine Y_2BaCuO_5(Y211) particles have been prepared by the top-seed modified powder melting process method, Solid-Liquid Melt Growth(SLMG), with Y_2O_3, BaCuO_2 and CuO mixing precursor. By using Y_2O_3 instead of Y_2BaCuO_5 as precursor, the processing became to be simpler and cheaper than the current powder melting process. The mic...

In this paper, 5 kWh class Superconductor Flywheel Energy Storage System (SFES) was constructed including motor/generator, superconductor magnetic bearing(SMB), composite rotor and electromagnetic damper(EMD) system. High speed rotation test was performed after levitating flywheel rotor only using EMD without SMB. the PD controller of EMD was desig...

A cryogenic thermosiphons is an efficient heat transfer device between a cryocooler and a thermal load that is to be cooled. This paper presents an idea of thermosiphon which contains two vertically-separated evaporators. This unique configuration of the thermosiphon is suitable for the purpose of cooling simultaneously two superconducting bearings...

YBCO coated conductors (CC) with high critical current density and index values are expected to be applied to superconducting power device. In particular, it is characterized by possibilities of selecting a stabilizing material surrounding YBCO CCs so that they could be applied to superconducting fault current limiters (SFCLs) and superconducting c...

In this paper, we manufactured a vertical axial type Superconductor Flywheel Energy Storage System (SFES) with journal type SMB using HTS for assessing the loss of SFES. The accurate method for measuring energy loss for each part of SFES was presented through the spin down test. Energy losses according to core type, coil thickness and leakage flux...

In our high-power flywheel energy storage system, the heavy and large flywheel is rotated by the electromagnetic torque of a permanent-magnet (PM) synchronous motor (PMSM) and, in case of a breakdown of electric current, this motor used as a generator supplies electric energy to the various electric utilities using mechanical rotation energy of the...

Energy loss is one of the most important problems for the practical use of superconductor flywheel energy storage (SFES) system. The energy loss of the SFES is mainly caused by drag force induced by magnetic field parts such as the superconductor magnetic bearing (SMB) and permanent magnet (PM)-type motor/generator (PMSM/G). In this paper, a vertic...

Industrial interest in switched reluctance motor (SRM) drives has varied since 1850s. This has been primarily due to the emerging markets for simple design geometry and low cost in consumer and industrial products, such as home appliances, air conditioning, hand tools, fans, pump motor, etc. However, SRM has been plagued with the acoustic noise and...

In this paper, the rotational loss of the superconductor flywheel energy storage system (SFES) by motor/generator stator core was assessed. To do this, the vertical axial type SFES with journal type superconductor bearing was manufactured. To quantitatively assess the rotational loss by the stator core, the rotational losses by superconductor beari...

The rotational loss is one of the most important problems for the practical use of superconductor flywheel energy storage system. The rotational loss of the SFES is mainly generated in the part of magnetic field such as superconductor bearing and motor/generator. The rotational loss of PM type motor/generator is much larger than that of superconduc...