• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.519-520
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• 2011

In Gas Insulated Substation(GIS), Very Fast Transient Overvoltages(VFTOs) are generated by the switching operation of disconnector or circuit breaker and it is propagated to each component of GIS. Each component of GIS is modeled by lumped line model and distributed line model based on equivalent circuits. The various cases which can be operated and the various closing point-on-wave are considered. In this paper, magnitude and rate-of-rise of VFTO are simulated and analyzed by comparing the simulation results. Measurements are performed at transformer and circuit breaker.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.305-307
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• 2001

In this paper, the household AC power line network is characterized for the low bit rate power line communication (PLC) in the frequency range from 10kHz to 450kHz. Various types of electric apparatus and the power lines constitute the network topology, and the PLC channel transfer function and the channel impedance are derived based on the constructed network topology. The channel characteristics derived with the lumped circuit model and the distributed circuit model are compared using the computer simulations. The effect of the wave reflection and signal distortions are also investigated.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.51 no.5
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• pp.197-202
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• 2002

In this paper, the characteristics of the household AC power line network is analyzed for the low bit rate powerline communication (PLC) in the frequency range from 10㎑ to 450㎑ The PLC channel transfer characteristics including its characteristic impedance are derived based on the network topology which is constructed with the household power lines loaded with the various types of electric apparatus. Both the distributed circuit analysis and the lumped circuit model based analysis are applied for the characterization of the PLC channel and the results are compared by the computer simulations. The analysis illustrates very well the adverse effects caused by the loading of electric apparatus and as well those casued by the reflection of wavers in the household AC Power line communication network.

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.108-111
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• 2000

The electrical characteristics of MQFP packages have been measured in RF regime. The s-parameter of the lead frame has been measured using the test fixture on which the do-capped package was mounted. A simple lumped equivalent circuit modeling of the lead frame and the test fixture can provide reasonable model parameters up to the frequency of 200 MHz.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.4
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• pp.8-12
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• 2003

Characteristics of optical transceiver module in radio frequency(RF) band were investigated with TO-can packaged Fabry-Perot laser diode(FP-LD). R-L-C parameters for equivalent circuit model of the LD were extracted with an impedance analyzer. With this model, impedance matching to the packaged LD could be performed by eliminating inductive components of the leads in the package by using lumped chip capacitors that have opposite reactance, while it shows resonance dip in low frequency band. The resonance dip could be removed using lumped elements for impedance matching by shifting the resonance frequency to the region out of interest.

• Journal of Electrical Engineering and Technology
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• v.10 no.1
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• pp.205-215
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• 2015

Common mode (CM) conducted interference are predicted and compared with experiments in a motor drive system of Electric vehicles in this study. The prediction model considers each part as an equivalent circuit model which is represented by lumped parameters and proposes the parameter extraction method. For the modeling of the inverter, a concentrated and equivalent method is used to process synthetically the CM interference source and the stray capacitance. For the parameter extraction in the power line model, a computation method that combines analytical method and finite element method is used. The modeling of the motor is based on measured date of the impedance and vector fitting technique. It is shown that the parasitic currents and interference voltage in the system can be simulated in the different parts of the prediction model in the conducted frequency range (150 kHz-30 MHz). Experiments have successfully confirmed that the approach is effective.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.537-540
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• 1991

This paper discusses with a voltage - fed Type high frequency inverter with simple main circuit and high efficiency. The proposed inverter is proper as a high frequency inverter of home applications applied with induction healing principle of high frequency. Further, its operating characteristics necessary to its design is estimated by analysis of a lumped circuit of heating system as a model.

• Journal of the Korean Society for Precision Engineering
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• v.34 no.4
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• pp.281-285
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• 2017

Since the performance of the spring operating mechanism for a circuit breaker mainly depends on the dynamic behavior and mass of the coil spring, its dynamic analysis is required to evaluate the performance of the spring operating mechanism. In this study, a coil spring design program is developed for the spring operating mechanism. An experimental approach is used to find the variables satisfying the design constraints' requirements. The coil spring is formed by using a lumped mass spring model. This program offers reference data for the design of coil springs and for the spring operating mechanism.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.2
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• pp.247-254
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• 2003

The paper presents the influence of spring dynamics and friction on dynamic responses in a spring-driven cam system. The characteristics of the friction on the camshaft are analyzed using the nonlinear pendulum experiment while the parameters of the friction model are estimated using the optimization technique. The analysis reveals that the friction of the camshaft depends on stick-slip, Stribeck effect and viscous damping. Spring elements are found to have much influence on the dynamic characteristics. Hence, they are modeled as four-degree-of-freedom lumped masses with equivalent springs. The appropriateness of the derived friction model and spring model is verified by its application to a vacuum circuit breaker mechanism of the cam-follower type.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.7
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• pp.370-378
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• 2002

As resent trends in structural construction have been to build taller and larger structures than any time in the past, they have had high flexibility and low damping that can cause large vibration response under severe environmental loading such as earthquakes, winds, and mechanical excitations. The damper with mass and spring is one approach to safeguarding the structure against excessive vibrations. In this paper, the lumped electrical circuit approach of mass/spring system is used to model the mechanical aspects according to the frequency. Therefore, the mass/spring system can be dealt with here and linked with the equivalent circuit of electric linear oscillatory actuator(LOA). Analysis models are two types of vibration control system, active mass damper(AMD) and hybrid mass damper(HMD). AMD consists of the moving coil LOA with mass only The LOA of HMD with mass and spring is composed of the fixed coil and the movable permanent magnet(PM) field part. The PM field part composed magnet modules and iron coke, is the damper marts itself. We Present the motional resistance and reactance of mass/spring system and the system impedance of AMD and HMD according to the frequency.