• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.127-132
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• 2001

In this paper, transmitted sound reduction performance of smart panels is studied according to different piezoelectric materials with piezoelectric shunt damping. Peizo-damping is implemented by using a newly proposed tuning method. This method is based on electrical impedance model and maximizing the dissipated energy at the shunt circuit. By measuring the electrical impedance at the piezoelectric patch bonded on a structure, an equivalent electrical model is constructed near the system resonance frequency. After shunting elements are connected to the equivalent circuit, the shunt parameters are optimally searched based on the criterion of maximizing the dissipated energy at the shunt circuit. Transmitted sound reduction performance is compared according to different piezoelectric materials with peizo-damping. Two piezoelectric materials are selected: PZT-5 and QuickPack IDE actuator. When resonant shunt circuit is considered, the use of PZT-5 exhibited the good sound reduction performance.

• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.1
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• pp.16-24
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• 2019

The performance of the battery management system (BMS) algorithm is important for ensuring the stability and efficient operation of battery packs. Such a performance is determined by the internal parameters of the electrical equivalent circuit model (EECM). This study proposes a performance improvement and verification of battery parameters for the BMS algorithm using electrical experiments and tools. The parameters were extracted through electrical characteristic experiments, and an EECM based on Ah counting was designed. Simulation results using the EECM were compared with actual experimental data to determine the best parameter extraction method.

• Proceedings of the KIPE Conference
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• 1998.11a
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• pp.49-54
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• 1998

This paper describes a simulation model to analyze the dynamic performance of Unified Power Flow Controller, which adjust flexibly the active and reactive power flow through the ac transmission line. The basic operation was analyzed in detail using equivalent circuits and the design of control system was developed using vector control method. A simulation model with EMTP code was conceived to evaluate the performance of the Unified power Flow Controller. The simulation results show that the developed simulation model is very effective to analyze the dynamic performance of the Unified Power Flow Controller.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.4
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• pp.339-346
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• 2012

In this paper, equivalent models for active control devices are proposed so that building structures with such devices are analyzed using commercial structural analysis programs for the assessment of the structural members under active vibration control. Equivalent link models represent active control device with a virtual linear spring and dashpot, and equivalent force models are control force history acting at the installation point in structural models. Active controllers are designed based on the reduced-order models for a vertical cantilever model and a high-rise building model and corresponding equivalent models are determined from control gain matrices. Based on acceleration, displacement and member force responses, the effectiveness of the equivalent models is verified. As a result, proposed equivalent models, of which equivalent link model showed better performance, appear to enable detailed investigation of structural behavior to the extent of member force level.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.22-24
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• 1997

The 4-pole LHSM was composed of the figure-of-eight shaped 3-phase armature windings. DC field windings, and the segmented secondary with the transverse bar track. The motor was designed on the base of the performance characteristic equations and the equivalent circuit model, with the coefficients of the magnetic shape. These coefficients were computed from the analytical expressions and examined from FEM analysis. The magnetic equivalent circuit of 3-D model of LHSM was obtained. and this concept provided the equivalent models for 2-D FEM analysis. Therefore, the airgap field, the lift and thrust force were calculated and compared with the results of magnetic equivalent circuit method.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.10
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• pp.852-860
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• 2003

We introduce the error models for an attitude determination system(ADS) with gyroscopes and stellar sensor. The ADS error models are derived according to the definition of the reference frame and of the attitude error. The equivalent error models applicable to the attitude determination system with large attitude errors are presented. The simulation results show that the proposed error models improve performance of the attitude determination system.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.5 s.39
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• pp.35-43
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• 2004

Small-scale models have been frequently used for seismic performance tests because of limited testing facilities and economic reasons. However, there are not enough studies on similitude law for analogizing prototype structures accurately with small-scale models, although conventional similitude law based on geometry is not well consistent in the inelastic seismic behavior. When fabricating prototype and small-scale model of reinforced concrete structures by using the same material, added mass is demanded from a volumetric change and scale factor could be limited due to aggregate size. Therefore, it is desirable that different material is used for small-scale models. Thus, a modified similitude law could be derived depending on geometric scale factor, equivalent modulus ratio and ultimate strain ratio. In this study, compressive strength tests are conducted to analyze the equivalent modulus ratio of micro-concrete to normal-concrete. Then, equivalent modulus ratios are divided into multi-phase damage levels, which are basically dependent on ultimate strain level. Therefore, an algorithm adaptable to the pseudodynamic test, considering equivalent multi-phase similitude law based on seismic damage levels, is developed. Test specimens, consisted of prototype structures and 1/5 scaled models as a reinforced concrete column, were designed and fabricated based on the equivalent modulus ratios already defined. Finally quasistatic and pseudodynamic tests on the specimens are carried out using constant and variable modulus ratios, and correlation between prototype and small-scale model is investigated based on their test results. It is confirmed that the equivalent multi-phase similitude law proposed in this study could be suitable for seismic performance tests on small-scale models.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.19 no.2 s.72
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• pp.187-194
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• 2006

Generally, earthquake-resistant structural systems have to ensure the sufficient stiffness and ductility for stability In this paper, the spatial structures are applied an isolation system to boundary parts between roof systems and sub-structures. So, it is necessary to examine the characteristics of dynamic behaviors of spatial structures governed by higher modes rather than lower modes different from the cases of high-rise buildings. The objectives of this paper are to develop the equivalent lumped mass model to simplify an analytical processes and to investigate the dynamic behaviors of roof systems according to the mass and stiffness of sub-structures as a fundamental study of performance design for the spatial structures.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.371-375
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• 2003

In this paper, a new design method for coupled-line filters with tapped input/output has been developed. The design equations for this tapped filter have been obtained using a new equivalent circuit model of tapped lines. From an edge coupled-line filter, tapped lines replaces the input/output coupled lines which tend to have very narrow gaps (few mils). Therefore, tapped coupled-line filters tend to be less sensitive to filter fabrication tolerances and to be easily fabricated using milling tools. The new filter design algorithm allows very accurate filter design for frequencies less than 20 GHz and bandwidth less than 20%. Above 20 GHz, the filter performance can be optimized starting from the filter design algorithm in this paper. Simulation problems with 2-D EM tools to characterize filter performance at high frequencies have shown to be solved by providing a channel for the filter to eliminate higher order modes.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.584-589
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• 2001

This paper presents the dynamic parameter design optimization of a suspension seat system using the genetic algorithm. At first, an equivalent 1-D.O.F. mass-spring-damper model of a suspension seat system was constructed for the purpose of its vibration analysis. Vertical vibration response and transmissibility of the equivalent model due to base excitations, which are defined in the ISO's seat vibration test codes, were computed. Furthermore, seat vibration test, that is ISO's damping test, was carried out in order to investigate the validity of the equivalent suspension seat model. Both analytical and experimental results showed good agreement each other. For the design optimization, the acceleration transmissibility of the suspension seat model was adopted as an object function. A simple genetic algorithm was used to search the optimum values of the design variables, suspension stiffness and damping coefficient. Finally, vibration ride performance test results showed that the optimum suspension parameters gives the lowest vibration transmissibility. Accordingly the genetic algorithm and the equivalent suspension seat modelling can be successfully adopted in the vibration ride quality optimization of a suspension seat system.