• Progress in Superconductivity and Cryogenics
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• v.6 no.3
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• pp.38-43
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• 2004

1MW class superconducting synchronous motor is designed considering several conditions such as superconducting wire length, machine efficiency and size. As the machine is larger and larger, the superconducting machine shows the advantages more and more over the conventional machines. Although the advantages at 1MW rating are not so great, the design approach to get an appropriate result would be very helpful for larger superconducting synchronous machine design. Major design concerns are focused on reducing expensive Bi-2223 HTS(High Temperature Superconducting) wire which is used for superconducting field coil carrying the rating current around 30K(-243$^{\circ}C$) while the machine efficiency is higher than conventional motors or generators with the same rating. Furthermore, some iron cored structure is considered to reduce the HTS wire requirement without bad effect on machine performances such as sinusoidal armature voltage waveform, synchronous reactance and so on.

• Progress in Superconductivity and Cryogenics
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• v.3 no.2
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• pp.21-26
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• 2001

Superconducting synchronous generators and motors are designed based on 2 dimensional electro-magnetic approach. In the case of generator, if the machine output rating and terminal voltage are decided the armature rating current will be decided automatically according to its power factor. However, in the case of motor, if the output rating is given with [hp] or [kw] units, the armature terminal voltage and current are not decided directly because the machines armature input power and mechanical output are different by way of losses. So in order to calculate the armature current more accurately. the machine losses must be included in the design procedure. In this paper the machine loss of superconducting motor are analyzed and used for decision of the armature input power and current. Moreover, the differences of voltage equations between superconducting synchronous generator and motor are considered.

• Proceedings of the KIEE Conference
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• summer
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• pp.809-811
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• 2004

A 1MW class superconductng synchronous motor is designed considering several conditions such as superconducting wire length, machine efficiency and size. As the machine is larger and larger, the superconducting machine shows the advantages more and more over the conventional machines. Although the advantages at 1MW rating are not so great, the design approach to get an appropriate result would be very helpful for larger superconducting synchronous machine design. Major design concerns are focused on reducing expensive Bi-2223 HTS(High Temperature Superconducting) wire which is used for superconducting field coil carrying the rating current around 30K($-243^{\circ}C$) while the machine efficiency is higher than conventional motors or generators with the same rating. Furthermore, some iron cored structure is considered to reduce the HTS wire requirement without bad effect on machine performances such as sinusoidal armature voltage waveform, synchronous reactance and so on.

• Progress in Superconductivity and Cryogenics
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• v.7 no.3
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• pp.21-28
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• 2005

Superconducting synchronous motors and generators have the field coil composed of superconductor with almost zero resistance at superconducting state. Therefore, copper 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 copper wire and supported by non-magnetic material such as FRP (Fiber Reinforced Plastic) This paper contains the design Procedure of a 1MW 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 KIEE Conference
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• 2002.07b
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• pp.720-722
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• 2002

Superconducting synchronous motor using HTS(high-temperature superconducting) field windings has a lot of advantages over LTS(Jow-temperature superconducting) synchronous machine. A recently developed 5000[hp] HTS motor represents 1/2 reduction in weight and volume compared to an induction type conventional machine. Furthermore. 40% machine loss is reduced compared to the industry average. Based on a conceptual design, a 100[hp] HTS synchronous motor is modeled by F.E.M(Finite Element Method) and the performance is predicted in this paper

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.865-867
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• 2001

Generally large synchronous rotating machines with 2 poles have more merits than the others with more than 2 poles Superconducting synchronous rotating machines also have the same tendency, but they have different structure from conventional ones because of no magnetic core inside of the rotor. As the result, design approaches of the superconducting field coils are also different, which would be classified into 2 types according to their coil shapes. The first one is race-track type and the other is saddle type Race-track type machines have almost the same structure with conventional salient pole generators which are being used as largely small scale machines with more than 2 poles. On the other hand saddle type machines correspond to conventional cylindrical generators with 2 poles used for large turbine system in power plants. In this paper several types of superconducting field coils are introduced for 2 pole superconducting machine design and then the feasibility of each type is considered. Moreover, based on the consideration. 1MVA superconducting generator(S.G.) with saddle type field coil is designed electromagnetically.

• Progress in Superconductivity and Cryogenics
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• v.9 no.3
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• pp.32-36
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• 2007

On the contrary of a conventional motor with very narrow air-gap. it is difficult to calculate the accurate magnetic field distribution and the performance of an air-cored superconducting motor by 2 dimensional analysis. which does not use high permeability material except outer machine shield. This paper aims to do analysis of magnetic field and force distribution from the 3 dimensional modelling of a 1MW class superconducting synchronous motor. Especially. the field coil composed of Bi-2223 high-temperature superconductor and the outer machine shield are modelled by finite element analysis software according to their structures and the self-inductance and Lorentz force are calculated based on the 3 dimensional magnetic field calculation. Moreover. the influence of an important parameter, synchronous reactance, has been analyzed on the machine performances such as voltage variation and output power.

• Journal of Magnetics
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• v.18 no.3
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• pp.260-267
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• 2013

In this paper a general 2-D model of a large air-gap synchronous machine either with non-magnetic or magnetic core rotor is investigated and electrical characteristics of the machine are analytically calculated. Considering the general model, analytical equations for magnetic field density in different regions of the large air-gap machine are calculated. In addition, self and mutual inductances in the proposed model of the machine have been developed, which are the most important parameters in the electromagnetic design and transient analysis of synchronous machines. Finite element simulation has also been performed to verify the obtained results from the equations. Analytical results show good agreement with FEM results.

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

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.3
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• pp.101-106
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• 2001

Air-cored superconducting synchronous generator(ASSG) is characterized by an air-cored machine with its rotor iron and stator iron teeth removed. For this reason, in the case of the shape optimum design of ASSG, other design variables different from an iron-cored machine should be considered, which will lead to substantial improvement on the performance. The major design variables that are considered by using Three-dimensional Finite element Method(3D FEM) in this paper are : 1) field coil width, 2) axial length of magnetic shield, and 3) armature winding method. End-ring of armature winding is considered in the calculation of EMF. When it comes to field coil width, as field coil width enlarges, its effective field increases but the maximum field on the superconductor decreases. this determines the critical current density. this study presents an effective field coil width, axial length of magnetic shield, and armature winding method, and also the analysis is verified by the experimental results.