• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.10
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• pp.501-506
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• 2003

A Superconducting Rotary Machine (SRM) is characterized by an air-cored machine with its rotor iron and stator iron teeth removed. For this reason, the SRM is featured by 3D magnetic flux distribution, which decreases in the direction of axis. Therefore, 3D magnetic field analysis method is required to know about characteristic of magnetic field distribution of SRM. In this paper, 3D flux distribution of SRM is calculated by analytical method. The magnetic field distribution of the field coils is calculated by Biot-Savart equation. The magnetic core is represented by magnetic surface polarities. This paper describes the combined use of above methods for the total field computation, and compares results of analytical method and 3D FEM(Finite Element Method).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05c
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• pp.47-50
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• 2001

Conventionally, air-cored Rogowski coil was designed for use as high alternating and transient current sensor without saturation caused by ferromagnetic material in its core. This paper investigated that Rogowski coil can be applied to low current measurement in 60Hz power line. Measured parameters R, L of coil were compared with theoretically calculated values. Output voltages crossed by Rogowski coil have shown some linearity according to input current(tens to thousands of amperes) passing through it. And also shielding effect for external noises was investigated for three cases.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.85-87
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• 1998

In general, we apply the 2 dimensional method to analyze the characteristic of electric machinery. But it is very difficult to analyze the air-cored machine like as superconducting generator, because it have 3 dimensional flux distribution. In this paper, we compare the analysis r between 2D and 3D. 3D Finite Element Meth applied to the superconducting generator at n condition. And we studied the characteristic acc to the axial length of magnetic shield.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.253-255
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• 1999

In this paper, a shape optimization algorithm of superconducting magnet using finite element method is presented. Since the superconductor loses its superconductivity over the critical magnetic field and critical current density, this material property should be taken into account in the design process. Trial and error approach of repeating the change of the design variables costs much time and it sometimes does not guarantee an optimal design. This paper presents a systematic and efficient design algorithm for the superconducting magnet. We employ the sensitivity analysis based on finite element formulation. As for optimization algorithm, the inequality constraint for the superconducting state is removed by modifying the objective function and the nonlinear equality constraint of constant volume is satisfied by the gradient projection method. This design algorithm is applied to an optimal design problem of a solenoid air-cored superconducting magnet that has a design objective of the maximum energy storage.

• Proceedings of the KIEE Conference
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• summer
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• pp.857-859
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• 2004

This paper presents design of speed control system for slot less air-cored PM linear synchronous motor using space vector PWM. The vector control requires information about rotor position. And we can need to the Hall sensor for sampling current. In order to agree with this purpose, Digital Signal Processor(TMS320F2406A) developed for implementation of a speed Field Oriented Control.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1057-1059
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• 2003

This paper presents drive analysis of slotless air-cored PM linear synchronous motor using two-dimensional analytical method. In order to calculate dynamic characteristic, back-EMF and linkage flux are calculated by Permanent Magnet Field and also inductance are given by slotless winding current coil. PMLSM drive simulation is performed by PI control system.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.103-105
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• 1998

This paper presents the compensated 2-D magnetic fields analysis of superconducting AC generator(SCG) by using efficient 2-D model. 3-D analysis is necessary for the accurate analysis because SCG has a large leakage flux owing to the air cored winding and end ring structure. However, in 3-D FEM, considering the movement of rotor is difficult, so efficient 2-D model which can compensate the leakage flux has been proposed and the movement of rotor is easily considered. The characteristics in transient state of SCG and the prime role of damper also have been evaluated.

• Progress in Superconductivity and Cryogenics
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• v.9 no.2
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• pp.31-34
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• 2007

Superconducting synchronous motors compared with conventional motors can reduce the motor size and enhance the motor efficiency for low-speed and high torque applications under the space constraints for propulsion system. Especially, homopolar superconducting synchronous motors (HSSMs) need less superconductor and lower magnetic flux density in superconductor field coil than air-cored superconducting synchronous motors (ASSMs). In addition, mechanical structure is more simplified and stability is increased because the superconductor field coil of HSSMs is not rotated in operation. In this paper, we present the outline of HSSMs including structure, characteristics and operational principles with the conceptual design of 5MW HSSM.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.4
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• pp.145-152
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• 2016

For a general office building having a center core, the distinction between the outer wall and the compartment should be clear, and it should be set at a stack effect pressure distribution acting on the respective compartment by a relative area ratio of the respective leak compartment. In the case of office buildings with an independent core for core there, some blocks of shares and exterior pressure distribution in buildings and office buildings typically have different characteristics. Therefore, if the stack effect reduction measures, designed on the basis of a general office building are applied to a stand-alone building, the core of the building should reflect the unique pressure distribution characteristics. This study, performed as part of the object corresponding to the flat plan of the building in the diversification trend, analyzed the stack effect that actually occurs in an office building having the properties intended for stand-core construction, and thus on the basis of and tested by the method of using a conventional stack effect reduction measures. Reviewed in the study, an independent cored office building that does not have the air flow path through the specific space with respect to the center core type office building has a feature, and the variation in characteristics of the pressure distribution inside the building according to this air flow path stack effect was reduced by a variety of measures that should be applied to determine the application.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1D
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• pp.35-43
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• 2008

This paper mainly deals with the performance evaluation of 33 asphalt sections of Korea Expressway Corporation Test Road (KECTR) during the past four years. Since the construction of the KECTR in December 2002, key performance indicators of asphalt pavements have been collected five times with an Automatic Road Analyzer (ARAN), and have been analyzed for permanent deformation, surface distress, and road roughness. Linear viscoelastic characteristics of four dense graded HMAs used in KECTR were investigated with a series of complex modulus test. The effect of air void in HMAs on dynamic modulus was investigate at two air void contents for a surface course HMA (19 mm Nominal Maximum Size of Aggregate). Layer densification due to traffic was estimated from air void contents of field cored samples, and was correlated with pavement distresses and performances. One of findings of this study was that both permanent deformation and cracking were suspectible to pavement temperatures, rather than traffic. However, it was found that road roughness was mostly affected by traffic loading.