• 전력전자학회:학술대회논문집
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• 전력전자학회 2019년도 전력전자학술대회
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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.

• Journal of Power Electronics
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• 제14권6호
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• pp.1130-1138
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• 2014

This study analyzes a ladder multilevel converter (double ladder topology) with the use of a new averaging modeling technique. This technique introduces an analytical method to compute for the switching losses and is used to conduct an in-depth analysis of the influence of the switching frequency and parasitic resistance of components on converter efficiency. The obtained results enable the selection of switches and switching frequency to minimize losses. Moreover, simulation results and experimental measurements validate the analytical calculations.

• 한국통신학회논문지
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• 제32권10C호
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• pp.1019-1024
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• 2007

본 논문에서는 무선 랜 시스템용 10비트 20MHz 파이프라인 아날로그-디지털 변환기 설계를 위해서 Verilog-A 언어를 사용하여서 모델링하였다. 변환기내 샘플 / 홀드 증폭기, 비교기, MDAC 및 오차 보정 회로 등의 구성회로들을 각각 모델링해서 모의실험 한 결과 HSPICE를 이용한 모의 실험 시간보다 1/50배로 단축되어서 시스템 모델링에 적합함을 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.195-197
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• 2001

This paper presents the circuit modeling and Control methods of PWM DC/DC Converter with Isolated dual outputs. The dual output converter topology is consisted of the two switch and single secondary winding. The control algorithm which is used by an adjusted PI control methods, of Dual Output PWM DC/DC converter is proposed in this paper. The proposed adjusted PI control method has faster response characteristics than conventional PI control methods at load change. The validity of the proposed adjusted control method is verified with the several interesting simulation results.

• 전력전자학회논문지
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• 제16권6호
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• pp.627-637
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• 2011

본 논문은 새로운 형상을 가지는 평면 변압기를 적용한 200W급 공진컨버터에 대한 내용이다. 제안된 평면변압기는 기존 누설인덕턴스가 작은 평면변압기와 달리 누설인덕턴스가 조정이 가능하여 원하는 공진 특성을 얻을 수 있는 특징을 가지는 저가형 고집적화에 용이한 변압기이다. 본 논문에서는 제안된 평면변압기를 적용하여 200W급 전원장치에 적용하여 실험하였으며, 실험결과와 이론적인 해석에 대해 서술하였다.

• 한국태양에너지학회 논문집
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• 제29권6호
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• pp.1-13
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• 2009

Photovoltaic conditioning systems normally use a maximum power point tracking (MPPT) technique to deliver the highest possible power to the load continuously when variations occur in the insolation and temperature. A unique method of tracking the maximum power points (MPPs) and forcing the boost converter system to operate close to these points is presented through deriving small-signal model and transfer function of boost converter considering input capacitor. This paper aims at modeling boost converter including fairly large equivalent series resistance(ESR) of input reservoir capacitor by state-space-averaging method and PWM switch model and compares both methods using Bode plots. In the future, properly designed controller for compensation will be constructed in 3kw real system for maximum photovoltaic power tracking control.

• Journal of Power Electronics
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• 제13권6호
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• pp.1008-1015
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• 2013

By using fractional calculus and the circuit-averaging technique, the modeling and analysis of a Buck converter with fractional order inductor and fractional order capacitor in discontinuous conduction mode (DCM) operations is investigated in this study. The equivalent averaged circuit model of the fractional order Buck converter in DCM operations is established. DC analysis is conducted by using the derived DC equivalent circuit model. The transfer functions from the input voltage to the output voltage, the duty cycle to the output voltage, the input impedance, and the output impedance of the fractional order Buck converter in DCM operations are derived from the corresponding AC-equivalent circuit model. Results show that the DC equilibrium point, voltage ratio, and all derived transfer functions of the fractional order Buck converter in DCM operations are affected by the inductor order and/or capacitor order. The fractional order inductor and fractional order capacitor are designed, and PSIM simulations are performed to confirm the correctness of the derivations and theoretical analysis.

• 전기학회논문지
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• 제61권12호
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• pp.1959-1963
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• 2012

Since electric railway load is variable largely due to starting and braking characteristics as well as various operation patterns, load modeling is not easy but complicated. For this reason, a simple technique for modeling of electric railway load of is required to analyze the AC substation system of electric railway. In this paper, a modeling technique of converter-based electric railway load is proposed and is tested using nonlinear loads on Matlab/Simulink.

• 한국태양에너지학회 논문집
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• 제34권1호
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• pp.91-97
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• 2014

This paper proposes a modeling of fuel cell which replaces dc source during simulation. Fuel cells are electrochemical devices that convert chemical energy in fuels into electrical energy. This system has high efficiency and heat, no environmental chemical pollutions and noise. Proton exchange membrane fuel cells (PEMFC) are commonly used as a residential generator. These fuel cells have different electrical characteristics such as a low voltage and high current compared with solar cells. And there are different behaviors in the V-I curve in the temperature and pressure. Therefore, the modeling of fuel cell should consider wide voltage range and slow current response and the resulting electrical model is applied to boost converter with fuel cell as an input source.

• 한국위성정보통신학회논문지
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• 제5권2호
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• pp.29-33
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• 2010

위성 산업은 상업적 군사적 유용성 등의 특성으로 인해 지속적인 발달이 이루어져 왔다. 이중에서도 위성의 전력 시스템은 위성의 수명에 직접적인 관련을 가지고 있으며, 실제 궤도상에서의 Test가 불가능한 특성을 보인다. 또한 저궤도 소형위성은 전력에 민감하므로, 효과적인 전력의 안정화 및 신뢰성 향상은 중요한 문제이다. 일반적으로 저궤도 위성의 전력은 각 부하의 특성에 따라 변환 및 제어가 이루어진다. 따라서 저궤도위성의 전력 시스템은 일반적으로 여러 단계의 전력 변환을 거치게 되므로, 신뢰성 향상을 위한 1차 및 2차 혹은 그 이상 단계의 Converter의 일반화 모델링 및 안정화를 위한 제어기 설계 및 외란에 의한 영향성의 분석이 요구된다. 본 논문에서는 저 궤도 위성 전력계 시스템의 전력 변환을 위한 Converter의 일반화 모델링을 통해 안정화 설계를 위한 파라미터를 추정하고 이를 통한 신뢰성 향상 및 최적 제어 방법에 대해 알아보기로 한다.