• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.1
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• pp.15-19
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• 2014

As the space of the wind power generator stator end is limited, it is difficult for us to place the inner evaporative cooling system in it. We use the non-overlapping concentrated windings scheme to solve the placing and cooling problem. The characteristic of a 5MW direct-driven permanent magnet generator with non-overlapping concentrated windings were analyzed under no-load, rating-load and short-circuit by (Finite Element Method) FEM for verification of design. We studied the connection methods of the stator windings and designed the end connection member. The heat dissipation of the stator end was simulated by FEM, the result showed that the end cooling could satisfy the wind generator operation needs. These results show that the direct-driven permanent magnet wind power generators with non-overlapping concentrated windings and inner evaporative cooling system can solve the cooling problem of wind power generator, and obtain good performance at the same time.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.6
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• pp.19-33
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• 2000

In this paper, we propose anew approach to the development of the automatic vision system to examine and repair the steam generator tubes at remote distance. In nuclear power plants, workers are reluctant of works in steam generator because of the high radiation environment and limited working space. It is strongly recommended that the examination and maintenance works be done by an automatic system for the protection of the operator from the radiation exposure. Digital signal processors are used in implementing real time recognition and examination of steam generator tubes in the proposed vision system. Performance of proposed digital vision system is illustrated by simulation and experiment for similar steam generator model.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.687-689
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• 2003

Recently, issues regarding environment and the diversification of dependence in oil are watched with keen interest. Wind power attracts most interest because of its high-energy efficiency with environment friendly functions. The paper discusses the development of a coreless axial-flux permanent magnet (AFPM) generator for a wind power system. Analyzed the Coreless AFPM generator by electromagnetic, and designed wind power generator with this. The 3 phase output of stator is rectified and fed to a common do link. The overall machine structure has high compactness and lightness, because of the lack of the iron core. The test results with a resistive load confirm the satisfactory operation of generator. Compared with conventional generator, the design has lower weight, lower Power loss and improved efficiency.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.277-281
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• 2004

The following paper proposes the new design of digital sine wave generator which allows users to define the phase shift of the out put sinewave according to user's demands. This new sinewave generator will have 2 outputs, cos(${\omega}_0n$) and cos(${\omega}_0n$+${\phi}$) The design of the new system starts from the construction of discrete time system with impulse response as cos(${\omega}_0n$) in a pair of conjugate complex poles and a pair of zeros at the origin and the real axis. If users want to make a phase shift of sign wave, users can change the position of zero at the real axis. The results of the experiment have shown that the new design of sign wave generator has generated sine wave with the correct phase shift according to the theory.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.10
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• pp.1822-1828
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• 2008

This paper presents design parameter calculation methodology and its realization to construction for the 10/350${\mu}s$ lightning impulse current generator(ICG) modelled as double exponential function waveform with characteristic parameters ${\alpha},{\beta}$. Matlab internal function, "fzero" was applied to find ${\lambda}={\alpha}/{\beta}$ which is solution of nonlinear equation linearly related with two wave parameter $T_1$ and $T_2$. The calculation results for 10/350${\mu}s$ lightning impulse current show very good accuracy with error less 0.03%. Two type of 10/350${\mu}s$ ICGs based on the calculated design circuit parameters were fabricated by considering the load variation. One is applicable to the MOV based Surge protective device(SPD) for less 15 kA and the other is to test small resistive devices such as spark gap arrester and bonding device with maximum current capability 30 kA. The tested waveforms show error within 10% in comparison with the designed estimation and the waveform tolerance recommended in the IEC 61643-1 and IEC 60060-1.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.227-228
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• 2010

Generated One-Time Password (OTP) is used only once. This attributes is to safety than to repeated use the same password. Recently, Park's proposed on "Design of A One-time Password Generator on A Mobile Phone Providing An Additional Authentication for A Particular Transaction" use challenge-response based one-time password generator. However, Challenge exchange problem and currently OTP the same security level. In this paper, Park's proposed OTP generator design for us analysis. And then presents a resolution to the problem and new system logic. New system strong to Man-In-Middle attack and replay attack. In addition, OTP security level is higher.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.9
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• pp.761-770
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• 2007

In this study, a swirl generator using delta wing was developed in order to simulate total pressure distortion and flow angle distortion. The delta wing was used for $65^{\circ}$-degree sweep back angle to satisfy the design performance for vortex core position, total pressure distortion(DC90) and swirl angle. To extend the swirling flow area, a $45^{\circ}$-degree vortex flap have applied to the delta wing. The swirl generator satisfied the design requirement of distortion coefficient in the flow distortion test to be applied to the simulation duct, and the performances of distortion for vortex core position and swirl angle using CFD(computational fluid dynamics) analysis results that was verified by flow distortion test results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.12
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• pp.48-57
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• 2009

This paper presents optimal design of direct-driven PM wind generator using MADS (Mesh Adaptive Direct Search). Optimal design of the direct-driven PM Wind Generator, combined with MADS and FEM (Finite Element Method), has been performed to maximize the Annual Energy Production (AEP) over the whole wind speed characterized by the statistical model of the wind speed distribution. In particular, the newly applied MADS contributes to reducing the computation time when compared with Genetic Algorithm (GA) implemented with the parallel computing method.

• Journal of Wind Energy
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• v.10 no.4
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• pp.20-27
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• 2019

High-speed shaft coupling in a wind power system transmits power and absorbs variations in length and spindle dislocation between the gearbox and generator. Furthermore, the coupling has an insulation function that prevents electrical corrosion caused by the flow of the generator's current into the gearbox and prevents overload resulting from sudden power failure from being transferred to the gearbox. Its design, functions, and part verification are described in the IEC61400 and GL Guidelines, which specify that the part must have a durability life of 20 years or longer under distance variation and axial misalignment between the gearbox and the generator. This study presents the design of a high-speed coupling through composite stiffness calculation, structural analysis, and comparative analysis of test and theory to identify the characteristics of high-speed coupling for a large-capacity 6 MW wind power generator. A prototype was fabricated by optimizing the manufacturing process for each part based on the design, and the reliability of the fabricated prototype was verified by evaluating the performance of the target quantitative evaluation items.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.6
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• pp.1037-1044
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• 2019

This study describes injection locking phenomena for multi-frequency generator design. For the design of the multi-frequency generator, we describe the basic theory of injection locking phenomenon and conduct a single injection locking experiment based on it. The experiments was conducted by applying injection signals that vibrates consistently to oscillators which vibrates unstablely compared to injection signals. Injection signal was applied using a Howland current source and circuit was designed using a Colpitts oscillator. The results of the experiment showed that each oscillator oscillates reliable when injection signals(840kHz, 500kHz) are injected. Through the results of a single injection locking experiment, it is confirmed that injection locking phenomena can be applied in the design of the multi-frequency generator.