• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.11B no.2
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• pp.15-21
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• 2001

This paper presents an improved characteristic analysis methodology for a 5-phase hybrid stepping motor. The basic approach is based on the use of equivalent magnetic circuit taking into account the localized saturation throughout the hybrid stepping motor. The finite element method(FEM) is used to generate the magnetic circuit parameters for the complex stator and rotor teeth and airgap considering the saturation effects in tooth and poles. In addition, the neural network is used to map a change of parameters and predicts their approximation. Therefore, the proposed method efficiently improves the accuracy of analysis by using the parameter characterizing localized saturation effects and reduces the computational time by using the neural network. An improved circuit model of 5-phase hybrid stepping motor is presented and its application is provided to demonstrate the effectiveness of the proposed method.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.804-807
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• 2005

In this paper, a double scotch yoke mechanism for moving simultaneously the fixed contact and moving contact of a gas circuit brake, is proposed and designed to improve the breaking characteristics of the circuit breaker. Firstly, the design parameters of the scotch yoke are kinematically determined from the desired design condition of the circuit breaker. Next, the stroke curve of the moving contact is designed by considering the design parameter and the specified opening characteristics of electric contacts. Based on the scotch yoke and stroke curve, the dynamics of the electric contacts is analyzed using ADAMS model of switch mechanism.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.2
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• pp.54-61
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• 2013

This paper presents transient response behavior and frequency-dependent ground impedance of a single carbon ground electrode. The ground impedance of the carbon ground electrode was measured as a function of frequency of injected currents and simulated by using the distributed parameter circuit model with due regard to the frequency-dependent soil parameters, and the transient response behavior of the carbon ground electrode against impulse currents were investigated. As a consequence, the frequency-dependent ground impedance of the carbon ground electrode showed the capacitive behavior, that is, the ground impedance decreases with increasing the frequency of injected currents and lowers at the fast front time of impulse current. It was found that the carbon ground electrode is effective in grounding system for lightning protection. The ground impedance simulated with due regard to the frequency-dependent soil parameters was in good agreement with the measured data. The adequacy of the simulation technique and the distributed parameter circuit model for the carbon ground electrode was verified. It is expected that the simulation methodology, which analyzes the frequency-dependent ground impedance of the carbon ground electrode proposed in this work, can be used in the design of a grounding system for protection against lightning.

• Progress in Superconductivity and Cryogenics
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• v.5 no.3
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• pp.26-29
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• 2003

Nowadays, one of the serious problems in KEPCO system is much higher fault current than the SCC(Short Circuit Capacity) of circuit breaker. As the superconductivity technology has developed, the HTS-FCL(High Temperature Superconductor-Fault Current Limiter) can be one of the attractive alternatives to solve the fault current problem. But the parameters of HTS-FCL should be designed optimally to have the best performance. Under this background, this paper presents the optimal design method of parameters for resistive type HTS-FCL using Monte Carlo technique.

• Journal of the Korean Society of Industry Convergence
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• v.5 no.2
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• pp.127-132
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• 2002

In this paper, the new claw pole type linear stepping motor(CPLSM) is proposed. And the magnetic equivalent circuit of CPLSM is derived by the structure of the CPLSM. The design parameter and the magnetic flux density of CPLSM are performed with three-dimensional finite element method.

• Proceedings of the KIEE Conference
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• summer
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• pp.587-589
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• 2004

In this paper analytical pattern classification of TRV waves created by double-frequency synthetic test circuit was proposed. According to the classified patterns of the TRV wave, calculation methods of 3 reference lines and 4 parameters characterizing the TRV wave wire proposed. These methods can be utilized to optimize test facility and to standardize test quality.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1999.11a
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• pp.189-194
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• 1999

This paper proposes a current-fed type high frequency inverter using a soft switching technology Zero-Voltage-Switching to reduce turn on and off loss at the switching. The analysis of the proposed circuit was described by using normalized parameter and operating characteristics have been evaluated as to switching frequency and parameters. The theoretical results are in good agreement with the experimental ones. In the future the proposed circuit is considered to be useful for induction heating applications.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.14-19
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• 1998

This paper has described about principle and form of proposed circuit made use of soft switching technology ZVS(Zero-Voltage-Switching) to reduce turn on and off loss at switching. also, the analysis of the proposed circuit has described by using normalized parameter and operating characteristics have been evaluated as to switching frequency and parameters. In addition, this paper proves the propriety of theoretical analysis in terms of the experiments.

• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.15-17
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• 1999

This paper proposes that optimal design using GA of BLDC motor. To estimate this optimal design method, the performance characteristics of BLDC motor is computed by the equivalent magnetic circuit network method and FEM. To estimate especially the dynamic characteristics of BLDC, we compute the parameter of electrical circuit using FEM.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.12
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• pp.59-65
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• 2014

Two input resistances converted from $S_{11}$-parameter and $Z_{11}$-parameter of MOSFETs with various gate finger numbers Nf were measured in low frequency region. The 1/Nf dependent input resistance from $S_{11}$-parameter exhibits much lower values than that from $Z_{11}$-parameter in the range of $Nf{\leq}64$. This 1/Nf dependence was theoretically verified by using Nf dependent nonlinear equation derived from a MOSFET equivalent circuit.