• Progress in Superconductivity and Cryogenics
• /
• v.15 no.1
• /
• pp.35-39
• /
• 2013

The superconducting Homopolar motor is manufactured and tested. Homopolar motor system is simple and solid as the field coil of the motor is fixed near the stator coil without rotating system. In this paper, a 5 kW fully superconducting homopolar motor which has high temperature superconducting armature and field coils is manufactured and tested in liquid nitrogen. The critical current test results of the used 2G superconducting wire, pancake coil for rotor winding and race-track coils for armature winding are reported. Also, the test result of rotating and operating performance is presented. The operating frequency is to be 5 Hz for low-speed rotating. The developed fully superconducting Homopolar motor is the world's first.

• KEPCO Journal on Electric Power and Energy
• /
• v.6 no.4
• /
• pp.467-472
• /
• 2020

The superconducting synchronous generator is one of the breakthrough elements for direct-drive wind turbines because it is light and small. Normally the superconducting one has copper armature windings in the stator and superconducting field windings on the rotor. The high resistance of the armature can make large copper losses, comparing with the conventional generators with a gear box. One of the solutions for the large copper losses could be a fully superconducting generator. But the high magnetic fields from the superconducting field windings on the rotor also make high perpendicular magnetic fields on the superconducting tapes in the armature windings. We have proposed a fully superconducting synchronous generator with dual field windings. It could immensely decrease the circumferential component of the magnetic field from the field windings at the armature windings. In this paper, we conceptually designed 3 types of superconducting synchronous generators. The first one is the fully superconducting one with conventional structure, which has superconducting armature windings in the stator and superconducting field windings on the rotor. The second one is the one with dual superconducting field windings and superconducting armature windings between them. The last one is the same as the third one except the structure of the armature. If the concentrated armature windings are superconducting ones with cryostats, then they cannot be installed within the span of 2 poles. So, we adopted 3 phases windings within 4 poles system. It makes more AC losses but can be manufactured really.

• Proceedings of the KIEE Conference
• /
• 1996.07a
• /
• pp.86-88
• /
• 1996

Using superconducting magnetic flux pump, thick power leads for a superconducting magnet could be replaced with thin string leads for the excitation magnet to the superconducting flux pump. We have developed a new type flux pump with high voltage output to shorten the charge and discharge time of the load magnet. The test of four stacked disks as the excither for the load magnet has been carried out. This disk type flux pump yielded 70 mV of voltage across its terminal and 10 A of current through 85 mH load magnet which was the field winding of 20 kVA class fully superconducting generator within 12 seconds. This output voltage of the new superconducting flux pump is about 10 times larger than that of the previous work Moreover since it is easy to stack the disks for the superconduction flux pump, the high voltage exciter for the 1H class superconducting magnet would be expected to be made easily.

• Journal of Electrical Engineering and Technology
• /
• v.10 no.2
• /
• pp.545-550
• /
• 2015

High Temperature Superconducting (HTS) synchronous generators can be designed with either an air-core type or iron-core type. The air-core type has higher efficiency under rated rotating speed and load than the iron-core type because of the iron losses which may produce much heat. However, the total length of HTS wire in the air-core type is longer than the iron-core type because the generated magnetic flux density of the air-core type is low. This paper deals with designs of 10 MW air-core and iron-core HTS wind power generators for wind turbines. Fully air-core, partially iron-core, and fully iron-core HTS generators are designed, and various stator winding methods in the three HTS generators are also considered, such as short-pitch concentrated winding, full-pitch concentrated winding, short-pitch distributed winding, and full-pitch distributed winding. These HTS generators are analyzed using a 3D finite elements method program. The analysis results of the HTS generators are discussed in detail, and the results will be effectively utilized for large-scale wind power generation systems.

• Progress in Superconductivity and Cryogenics
• /
• v.20 no.2
• /
• pp.20-23
• /
• 2018

The practical use of superconducting magnets is limited to medical equipment, energy equipment and the like. Therefore, it does not fully utilize the superior features of superconducting magnet or magnetic force. In order to overcome this blockage condition, The international Forum on Magnetic Force Control (IFMFC) was launched in Tokyo in 2010 by the magnetic separation researchers in Japan, Korea and China. The policy is to hold around the country every year, to apply the application to the engineering field of magnetic force utilization and information exchange about the development of applied science to mutual visit of researchers and to develop the application field of superconducting magnets in particular. The main object is to review the field of application of magnetic force with respect to published papers at 8 IFMFCs, and to introduce the trend of research forum utilizing strong magnetic force which is rare in the world. The United Nations is asking each country to achieve Corporate Social Responsibility (CSR) targets for 2030. This IFMFC review will be utilized in this field.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 2003.10a
• /
• pp.45-48
• /
• 2003

Ramp-rate limitation is a serious obstacle for successful operation of fast charging and discharging magnet Ramp-rate limitation is hard to expect or fully investigate due to its electric and thermo-hydraulics couplings. In this paper, the simplest case of ramp-rate limitation is investigated with two-strand superconducting cable model considering transient heat transfer The simulation results are compared with the experimental results.

• Superconductivity and Cryogenics
• /
• v.21 no.2
• /
• pp.2-6
• /
• 2019

• Progress in Superconductivity and Cryogenics
• /
• v.19 no.1
• /
• pp.5-8
• /
• 2017

A series of high gradient superconducting magnetic separator (HGMS) for kaolin has been developed. It is used for processing kaolin to increase the brightness or whiteness whether it is for paper or ceramic applications. The HGMS system mainly consists of a solenoid magnet with a zero boil-off helium cryostat, a double reciprocating canisters system, and a PLC (Process Logic Controller) fully automatic control system based on SCADA (Supervisory Control and Data Acquisition) system. We have successfully developed CGC-5.5/300 and CGC-5.0/500 HGMS systems in the recent years, and now three sets of them are on-site operation in different customers. This paper will present recent progress of the HGMS system, the results of some experiments on processing kaolin clay used HGMS, and the on-site operation.

• Proceedings of the KIEE Conference
• /
• 2005.07b
• /
• pp.1258-1260
• /
• 2005

Superconducting synchronous motors and generators have the field coil composed of superconductor with almost zero resistance at superconducting state. Therefore, co or loss at the conventional field coil is eliminated and the superconducting machine gets higher efficiency. The armature coil of the superconducting machine is composed of cower wire and supported by non-magnetic material such as FRP(Fiber Reinforced Plastic). Although a fully-superconducting machine with superconducting armature coil has been researched, it was not developed toward industrial application because of AC transporting loss and difficulty in construction of the cooling structure and so on. This paper contains the design procedure of a 1 MW superconducting synchronous motor using high-temperature superconductor only for the field coil. Especially, the armature coil is designed by water-cooling in order to dissipate Joule heat easily. Moreover, 3-dimensional electromagnetic design is conducted to get a proper design result and reduce design errors from 2-dimensional approach.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 2001.02a
• /
• pp.131-131
• /
• 2001

FY2000, Japanese government has started three new projects on superconductive power application. Two are succeeding projects of flywheel energy storage and superconducting generator. The other one is fully new project on ac application of superconductivity. Therefore, there are four national projects in Japan on power application of superconductivity, including SMES project Though each project will be reviewed in detail in my talk, outlines are as follows; SMES : FY1999-FY2003, carried by ISTEC Superconducting generator: FY2000-FY2003, carried by Super-GM AC application: FY2000-FY2004, carried by Super-GM Flywheel energy storage: FY2000-FY2004 carried by ISTEC.