• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.35-37
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• 2005

Large generators are subject to high mechanical and electrical stress which may lead to deterioration of the insulation. The rotors, in particular, may develop short circuits particularly and there is a need for the operators to be aware of this situation. In this paper, the electromagnetic characteristics of the generator with shorted turns in rotor field winging is analyzed by FEM and the detection algorithm method of the shorted turn rotor slot position is proposed.

• Journal of the Korean Magnetics Society
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• v.5 no.2
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• pp.103-108
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• 1995

We propose an analyzing method of the harmonics of output voltage in salient pole syochronous generator. In simulation, 2-D finite elerrent method is used for calculating the stator coil flux linkage considering the rotor movement. As an application of the proposed method, we calculated the harrronics of output voltage in the 150 kw class syochromus generator and compared it with the experirrental result.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1312-1314
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• 2001

This paper presents a constant power controller for doubly-fed. Induction generators used in wind turbines. When the stator side of the generator is connected to the grid, the generated power depends on the rotor current. To control the rotor current based on it's average value, a cost effective SPC (Slip Power Controller) was developed and is ready for testing with an actual 660KW generator system. Experiment results are presented and discussed.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.28-30
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• 1989

This paper is analyzed the electrical characteristics of the round solid rotor of turbo-generator without damper cage influence the induction generation modes and the torsional interaction modes of the SSR phenomena, and then examines the problem of representing electrical characteristics which is dependent on frequency and different wedge materials. The basic model of turbo-generator used in the field analysis is viewed as 5-regions of different permeability and conductivity characteristics. The analytical method, which is used in this paper is based on solving a boundary value problem involving 3-D fields, and the basic function consists of the 2-D Fourier series.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.849-853
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• 2000

The retaining rings used to restrain the end turns of the rotor winding against centrifugal force require very careful attention during design and manufacture because they have traditionally been the highest-stressed components of the generator. In other words, the rings maintain their shrink fits during their entire service life. In this study, using finite element method, the part of shrink fits in generator was analyzed to obtain residual stresses in retaining ring and contact Pressures between contact surfaces at zero, rated, and 120 rated speeds, respectively.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1250-1254
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• 2004

To develop more compact and light generators which have high capacity, the most important thing that should be considered is the inner cooling system. Under all circumstances, the temperature of rotor and stator windings must be kept below the maximum temperature of insulation to maintain reliability and prolong durability of the machine. Therefore, the development of more effective cooling system and the exact prediction of windings are essential to produce our unique generator model which is reliable and competitive in international market. In this study, the flow of cooling air and the temperature distribution of winding is analyzed by using computational fluid dynamics. This analysis can lead to optimize the structure of cooling system and predict a local temperature rise.

• Proceedings of the KIEE Conference
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• summer
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• pp.785-787
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• 2004

The purpose of this paper is characteristic analysis of permanent magnet generator for AVR power of brushless synchronous generator. However, the PMG has a spoke type rotor with overhang, so we perform the analysis considering overhang for the precise airgap flux density. In this paper, dynamic analysis model with 2D FEM considering overhang is proposed by use of 2D, 3D static FEM results. The proposed method is verified by the results of PMG load test.

• Journal of Power Electronics
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• v.10 no.2
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• pp.194-202
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• 2010

The main cause of degradation in an unbalanced stand-alone doubly-fed induction generator (DFIG) system is negative sequence components that exist in the generated stator voltages. To eliminate these components, a hybrid current controller composed of a proportional-integral controller and a resonant regulator is developed in this paper. The proposed controller is applied to the rotor-side converter of a DFIG system for the purpose of compensating the negative stator voltage sequences. The proposed current controller is implemented in a single positive rotating reference frame and therefore the controller can directly regulate both the positive and negative sequence components without the need for sequential decomposition of the measured rotor currents. In terms of compensation capability and accuracy, simulations and experimental results demonstrated the excellent performance of the proposed control method when compared to conventional vector control schemes.

• Journal of Electrical Engineering and Technology
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• v.5 no.1
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• pp.61-69
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• 2010

This paper presents a study of a DFIG wind power generation system for real-time simulations. For real-time simulations, the Real-Time Digital Simulator (RTDS) and its user friendly interface simulation software RSCAD are used. A 2.2MW grid-connected variable speed DFIG wind power generation system is modeled and analyzed in this study. The stator-flux oriented vector control scheme is applied to the stator/rotor side converter control, and the back-to-back PWM converters are implemented for the decoupled control. The real-wind speed signal extracted by an anemometer is used for a realistic, reliable and accurate simulation analysis. Block diagrams, a mathematical presentation of the DFIG and a control scheme of the stator/rotor-side are introduced. Real-time simulation cases are carried out and analyzed for the validity of this work.

• Journal of Wind Energy
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• v.5 no.1
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• pp.50-55
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• 2014

Surface Permanent-Magnetic-Synchronous-Generator (SPMSG) discussed in the present study has operational characteristics such as high rotational speed over 1,000 rpm and centrifugal force of 12 kN·m for each magnet. Structure-development analysis for the minimization of rotor-core weights and the maximization of thermal emission is performed by applying the aluminum-laminated cap which combines the advantages of IPM and SPM in order to overcome the difficulty that attaching the magnet to rotor-core only with an adhesive. In this study, the simulations in terms of structure and electromagnetic were performed with the variable parameters such as shape and thickness of laminated-cap and division method of magnet. As a result, condition for minimized centrifugal force with minimum loss is derived.