• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.7
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• pp.1514-1519
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• 2003

This paper presents modeling and analysis of static and dynamic characteristics in three phase PWM Boost AC-AC converter used for input voltage sag compensation of custom power. Especially, using circuit DQ transformation technique, an equivalent circuit in fundamental frequency domain is obtained which has all the system characteristics. Moreover, voltage gain and input power factor is analytically induced and linearized state equation at the specific operating point is given. Finally, PSIM simulation results show the validity of the Nosed modelling and analyses.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.7 no.3
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• pp.57-66
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• 1993

This research proposes a high frequency series resonant inverter consisting of equivalent half - bridge model in combination with two L-C linked full-bridge inverter circuits using MOSFET. As a output power control strategy, the sequential gate control method is applied. Also, analysis of operating MODE and state equation is described. From the computer simulation results, the inverters and devices can be shared properly voltage and current rating of the system in accordance with series and parallel operations. And it is confirmed that the proposed system has very stable performance.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.2
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• pp.227-236
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• 1999

The finite difference time domain method (FDTD) is widely applied to the analysis of various microwave circuits. However, previous source modeling techniques have a lot of constraints and difficulties to apply for general geometries. Therefore, the internal resistive source modeling technique is suggested for efficiently analyzing various types of microwave circuit in this paper. Its efficiency is proved by comparing the computation time with that of hard source modeling. Accuracy is also verified by comparing the scattering parameters with those of previous source modeling methods and measurements for several microwave circuits.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.6
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• pp.528-537
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• 2002

In this paper, the extended FDTD is used for the analysis of microwave circuits including active elements. Lumped elements such as R, L, C which are inserted into a microstrip line are analyzed with the FDTD lumped element modeling. Parasitic capacitance and inductance could be obtained using network modeling and so it is sure that FDTD lumped element modeling makes it possible to get more accurate data which include parasite components. Moreover, a balanced mixer using two diodes that are modeled by an extended FDTD is designed and the more exact characteristic of the mixer is acquired than in current circuit simulator.

• Journal of the Korean Institute of Telematics and Electronics
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• v.8 no.3
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• pp.33-39
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• 1971

• Journal of the Korean Institute of Telematics and Electronics
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• v.6 no.1
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• pp.33-38
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• 1969

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.2
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• pp.101-107
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• 2002

High performance packages must protect circuits from the internal leakaged-electromagnetic fields as well as the surrounding. In this paper, we characterized an electromagnetically-shielded millimeter-wave ceramic package from 20 to 40 ㎓ using FEM(Finite Element Method). From these calculation results, the parasitic resonance is observed at 33.4 ㎓. We use metal-filled via-holes at the ceramic package walls and resonance has been suppressed in a frequency range from 20 to 40 ㎓. These calculation results will be helpful for MMIC packaging using electromagnetically-shielded millimeter-wave ceramic packages.

• The Transactions of the Korea Information Processing Society
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• v.3 no.5
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• pp.1130-1137
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• 1996

Every neural network has some kind of feedback. For the sake of analyzing fundamental aspects of information processing in neural nets, a net without feedbacks is an important theoretical model. But here we focus on a recurrent neural net which delay synapses as a realistic dynamical model of nervous systems. Synaptic connections are determined by a version of the Hebb rule (correlation type rule). We use a statistical neurodynamic method to explain the retrieval dynamics of the network. The result of the analysis for the sequential associativ e memory with delay synapses is compared with computer simulation. We have succeeded in explaining the dynamics of this network by theoretical analyses.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.4
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• pp.817-824
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• 2000

This paper presents circuit DQ modeling and analysis of operating characteristics of hybrid cascade multilevel PWM rectifier, especially five-level, without isolation transformers. The circuit DQ transformation changes the original three-phase time varying circuit to stationary equivalent one by employing the synchronously rotating transformation matrix. As a result of circuit DQ modeling, the operating characteristics and some useful design relationships for the system are obtained with ease. That is, the analytic equations for DC voltages and active/reactive power supplied by source with respect to control variables are Presented. Moreover, the DC voltages for the multilevel output generation may be directly built up from AC utility source and the important control equation ensuring 5-level output voltage is obtained. Finally, to confirm the validity of the analysis, MATLAB simulations are carried out and the simulation results show good agreements between analytic predictions and the simulated waveforms.

• Proceedings of the KIEE Conference
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• 2004.10a
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• pp.131-133
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• 2004

본 연구는 출력단에 패캐시터를 갖고 있는 AC 전류원으로부터, 밧데리 충전을 위한 새로운 AC/DC 컨버터 회로를 제안한다. 영전압과 영전류 스위칭을 사용하여 컨버터의 소형화 및 고효율화를 추구하였고, 풀브리지 MOSFET 정류기와 Buck-boost 컨버터가 결합된 새로운 토폴로지의 회로를 구성하였다. 제안된 컨버터의 동작원리 및 동작모드를 해석하고, PSpicc 시뮬레이션을 통해 해석결과를 검증하였다.