• Proceedings of the KSR Conference
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• 2006.11b
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• pp.665-674
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• 2006

This paper presents the optimal design of a high-speed (200[km/h]) Linear Synchronous Motor which will be used as a propulsion system of a dynamic tester for catenary-current collection used in railways. Motor performance, especially detent force minimization on various design schemes has been investigated in detail by using FEM (Finite Element Method). Simulation-based DOE (Design of Experiments) method is also applied in order to reduce the large number of analysis according to each design variable and consider the effect among variables. The optimal design in all aspects is proposed by an optimization algorithm using a regression equation derived from the simulation-based DOE and the performance is verified by FEM.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.2
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• pp.62-66
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• 2015

Induction generator is easy to durability and maintenance than the synchronous generator. So, recently Induction generator has been widely applied to small-scale hydroelectric power plant. When the rotor is operating faster than synchronous speed, induction machine can generate electric power. Induction generator has a large inrush currents, such as the starting current of the induction motor. Induction motor has been designed a variety of rotor shape in order to reduce starting current. Since the occurrence of high inrush current cause a voltage drop to the system, it will need to reduce possible. Because the starting current of the squirrel-cage induction motor varies in accordance with the rotor shape, it is necessary to analyze the magnitude of inrush current in order to apply to the generator. In this study, we analyzed the inrush current and the voltage drop caused in accordance with the rotor shape of 1500kw induction generator.

• Progress in Superconductivity and Cryogenics
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• v.10 no.3
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• pp.36-42
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• 2008

The superconducting motor shows several advantages such as smaller size and higher efficiency against conventional motor especially utilized in ship propulsion application. However, this size reduction merit appears in large capacity more than several MW. We are going to develop a 5MW class synchronous motor with rotating High-Temperature Superconducting (HTS) coil. that is aimed to be utilized for ship propulsion so it has very low-speed, The ship propulsion motor must generate very high electromagnetic torque instead of low-speed. Therefore. the rotor (field) coils need very large magnetic flux that results in large amount of expensive HTS conductor for the field coil. In this paper a 5MW HTS motor for ship propulsion is considered to be designed with construction cost reduced via HTS field coil cost reduction because HTS conductor cost is critical factor in the construction cost of HTS motor. In order to reduce the HTS conductor amount. iron-cored rotor types are considered. so several cases with iron-core are compared one another and with an air-core case.

• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.2
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• pp.104-112
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• 2006

SFC(Static Frequence Converter)system has come to be used as drive large synchronous machine in many industry applications. Many papers have been presented on the control algorithm of SFC system, not the acceleration and start-up but the rated speed operation with line connection and the braking operation with regeneration which is used in the industry. Among this, this paper presents the regeneration breaking control algorithm for a large synchronous machine using SFC system. The results of experiment show that the proposed algorithm is proper and effective.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.12B no.1
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• pp.1-6
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• 2002

The severe problem in improving the positioning precision of a permanent magnet linear synchronous motor (PMLSM) is the large detent farce caused by the permanent magnet arrangement. It is generally an undesired effect that contributes to the torque ripple, vibration and noise of machine. The detent force is arisen from the difference of the position of a permanent magnet end and a tooth position. In this paper, the four methods to reduce detent force were studied and analyzed. The methods are adjusting the width of permanent magnet, varying the shape of armature teeth, relocating the permanent magnet, and adjusting the width of permanent magnet and relocating the permanent magnet at the same time. To analyze the detent farce according to flour methods, a two-dimensional Finite Element Analysis [FEA] was used and we compared with the ratio of reduction of the detent farce according to the flour methods.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.700_701
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• 2009

In comparison with conventional motors, Superconducting Homopolar Synchronous Motors (SHSMs) have advantages that it generates high magnetic field by superconducting winding. Therefore, superconducting coil used in SHSM can reduce the motor size and enhance the motor efficiency for high torque applications under the space constraints for propulsion system. During the design process of SHSM, it is required to evaluate the performance of initial design model, that is accurately analyzed using 3D magnetic field modeling large air-gap and flux distribution of axial direction is properly taken into account. In this paper, we analyze magnetic field of a homopolar motor with a 4-pole homopolar rotor and a stator of 3 phase windings. The field analysis is done using 3D finite element analysis which can reflect the end effect and overhang winding. And we extract mutual inductances between a rotor wind and the 3 stator windings. The extracted inductances are used for evaluation of overall motor performances that are calculated with generalized circuit theory of electrical machines.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.9
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• pp.442-447
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• 2003

Motors with HTS wires or bulks have been developing recently. Those are large synchronous motor with HTS wires at the field winding in the rotor, hysteresis and reluctance motors with HTS bulk in the rotor. This paper presents the fabrication and test results of an HTS induction motor. Conventional end rings and short bars were replaced with HTS wires in the motor. Stator of the conventional induction motor was used as the stator of the HTS motor. Rated capacity and rpm at full rotor of the conventional motor were 0.75[kW] and 1,710[rpm]. Two, HTS wires are used in parallel to make the end rings and bars. The critical current of the BSCCO-2223 HTS wire which was used in the bars and end rings were 115[A]. Electrodynamometer was coupled directly to the shaft of the rotor with HTS wires.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2002.02a
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• pp.215-218
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• 2002

HTS motors and generators have some advantages over LTS machines because of higher operating temperature. Very low temperature nakes LTS machines need higher refrigeration cost and large facilities. However, HTS machines are expected to be comparable with conventional counterparts at smaller machine ratings than LTS generators in terms of efficiency and size. As the operating temperature increases, the magnetic flux density generated by HTS field coils decreases relatively. For example, 1000hp HTS synchronous motor developed in a few years ago has maximum field density of 1.5T. At this point, magnetic material used in conventional machines is able to pass magnetic flux easily with high permeability. In order to investigate the effect, we arranged magnetic core only inside of magnet vessel of a 100hp target machine. By way of FEM analysis, we concluded that the magnetic core can reduce amount of expensive BSCCO conductor so much.

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.1
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• pp.1-8
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• 2013

Surface permanent magnet-type vernier motors with three magnet array-type rotors (parallel magnetized type, repulsion type, and Halbach type) are compared based on the pull-out torque. It was clarified that increasing the rotor radius increases the pull-out torque at a fixed three-phase alternating voltage. The mechanism for the pull-out torque increase on each magnet array type was different, when the effects of the increase were analyzed based on an induced electromotive force and a synchronous reactance. As a result, the design of the Halbach-type rotor was found to be especially effective for achieving high pull-out torque, because this array type achieves a large induced electromotive force $E_0$ and a small synchronous reactance $x_s$.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.757-759
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• 2000

The problem in improving the positioning precision of a permanent magnet linear synchronous motor(PMLSM) is the large detent force caused by the permanent magnet. The detent force is thought to arise from the difference of the position of a permanent magnet end and a tooth position. In this paper, Three methods of reducing detent force is presented The first method is adjusting the width of permanent magnet. The second method is varying the shape of armature teeth. The third method is the arrangement of the permanent magnet end. This paper compares with the ratio of reducing the detent force according to the three methods.