• The Transactions of the Korean Institute of Power Electronics
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• v.20 no.2
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• pp.167-174
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• 2015

This study describes how digital time delay deteriorates control performance in zero voltage switching (ZVS) phase-shifted full bridge (PSFB) converter. The small-signal model of the ZVS PSFB converter is derived from the buck-converter small-signal model. Digital time delay effects have been considered according to the digital sampling methods. The analysis verifies that digital time delays reduce the stability margin of the converter, and the double sampling technique exhibits better performance than the single sampling technique. Both simulation and experimental results based on 250 W ZVS PSFB confirm the validity of the analyses performed in the study.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.94-97
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• 2008

In this paper, A Digital Voltage Mode Controller is designed for the Photovoltaic power converter applications. The designed Digital Voltage Mode Controller is derived analytically from the continuous time small signal model of the boost converter. Due to the small signal model based derivations of the control law, the designed control method can be applicable to K-factor Approach method and bilinear transformation. In order to show the usefulness of a designed controller, and the simulation results are verified.

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2518-2521
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• 1999

A Full-bridge zero-voltage zero-current switching (ZVZCS) converter using transformer auxiliary winding is analyzed. A complete small-signal model for the control scheme is developed. The propoed model is accurate up to half the switching frequency. The dynamic characteristics are compared with those of the zero-voltage switching converter and buck converter. Model predictions are confirmed by experimental measurements.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.4
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• pp.347-355
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• 2005

In this paper, a new continuous~time small signal model of an average current mode control is proposed. Sampling effect Is considered to obtain the proposed small signal model. By the proposed model, the high frequency response characteristics of current loop gain might be predicted accurately compared to previous models. And this leads the prediction of inductor current response of the proposed model to be accurate compared to others. In order to show the usefulness of the proposed model, prediction results of the proposed model are compared to those of the circuit level simulator, PSIM and experiment.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.5 no.6
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• pp.63-68
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• 1982

We can reduce delays and number of stops in the traffic area by means of optimal design of traffic signal system. A computer simulation model to simulate and predict the traffic signal system of Jong-Ro 4-th street was developed for determination of optimal cycle time. This simulation model was developed in relation to Jong-Ro 4-th street, but this model can be applied for other places with small modification.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.49 no.4
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• pp.1-6
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• 2012

This paper presents the extraction and analysis of small-signal parameters of tunneling field-effect transistors (TFETs) by using TCAD device simulation. The channel lengths ($L_G$) of the simulated devices varies from 50 nm to 100 nm. The parameter extraction for TFETs have been performed by quasi-static small-signal model of conventional MOSFETs. The small-signal parameters of TFETs with different channel lengths were extracted according to gate bias voltage. The $L_G$-dependency of the effective gate resistance, transconductance, source-drain conductance, and gate capacitance are different with those of conventional MOSFET. The $f_T$ of TFETs is inverely proportional not to $L_G{^2}$ but to $L_G$.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.357-360
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• 2000

This paper describes a parameter extraction method for HBT(Heterojunction Bipolar Transistor) equivalent circuit model without measurements of special test structures or numerical optimizations. Instead, all equivalent circuit parameters are calculated analytically from small-signal S-parameters measured under different bias conditions. These values being extracted from the cutoff mode can be used to extract intrinsic parameters at the active mode. This method yields a deviation of about 1.3 % between the measured and modeled S-parameters.

• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.957-960
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• 2000

A novel extraction method of high frequency small-signal model parameters for MOSFETS is proposed. From S-parameter measurement, this technique accurately extracts the model parameters including the charge conservation capacitance parameters. To consider charge conservation, nonreciprocal capacitance is considered. The modeled parameters fit the measurements very well without any optimization.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.317-319
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• 2019

In this paper, a three level duty cycle controlled half bridge LLC converter for EV charger application is presented. The topology and operating regions of the converter are discussed. The equations of the converter are derived in time domain. A small signal model of the converter is developed by perturbation and linearization of the steady state model about their operating point using Extended Describing function.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.5
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• pp.829-833
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• 2007

In this paper, the RCF method is applied to analyze small signal stability of power systems including GTO controlled parallel FACTS equipments such as STATCOM. To apply the RCF method in power system small signal stability problems, state transition equations of generator, controllers and STATCOM are presented. In eigenvalue analysis of power systems, STATCOM is modelled as the equivalents voltage source model and the PWM switching circuit model. As a result of simulation, the RCF method is very powerful to calculate the oscillation modes exactly after the switching operations, and useful to analyze the small signal stability of power systems with periodically operated switching devices such as STATCOM.