• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 전력전자학술대회 논문집
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• pp.345-346
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• 2016

The grid-connected energy storage systems, which could increase the reliability, efficiency, and cleanliness of the grid is presently restricted by the high cost of batteries. This problems could be solved by batteries retired from automotive services. These batteries can provide a low-cost system for energy storage and other applications such as residential applications and renewable energy integration. This paper gives an overview of technical requirements for the re-use of the electric vehicle batteries in energy storage systems.Firstly, the motivation of research is introduced. Secondly, the technologies needed for the re-use of the battery are introduced such asidentification of the battery characteristics, grading of the aged batteries, identification of the state-of-charge and state-of-health of the battery and suitable power electronic converter topologies. In addition the control strategy to maximize the battery lifespan and bypass the faulty batteries is presented and one-stop solution to implement the above mentioned technologies are also given.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 전력전자학술대회 논문집
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• pp.229-230
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• 2016

기존 자가발전 운동기구용 컨버터의 경우, 운동레벨을 조절하기 위한 입력임피던스 조절기능이 없거나, 조절기능을 추가하는 경우 복잡한 topology를 동반되는 경우가 일반적이다. 또한 복잡한 회로를 추가하게 되면 회로의 전체적인 부피가 증가하고, 원가가 상승할 뿐만 아니라, 회로의 신뢰성도 현저하게 저하시키는 등 회로 상용화를 어렵게 만든다. 본 논문에서는 입력 전압 및 전류 제어 방식을 이용하지 않고, 컨버터 구조 자체로 입력 임피던스를 제어하는 방식을 제안한다. 제안 방식은 입력전압, 입력전류 두 가지의 제어를 실행하지 않음으로써 복잡한 피드백 제어 단의 삭제가 가능하며, 이를 통해 회로의 높은 신뢰성 및 부피, 원가 감소 효과를 얻을 수 있다. 본 논문에서는 Flyback 컨버터를 이용하여, 이론적 특성 분석과 200W급 시작품을 통한 실험적 분석을 통해 그 타당성을 검증한다.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 추계학술대회 논문집
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• pp.337-340
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• 2007

In the dissertation, a power conversion system for fuel cell is composed of a PWM inverter with LC filter in order to convert fuel cell voltage to a single phase 220[V], In addition, new insulated DC-DC converters are proposed in order that fuel cell voltage is boosted to 380[V]. In this paper, it requires smaller components than existing converters, which makes easy control. The proposed DC-DC converter controls output power by the adjustment of phase-shift width using switch S5 and S6 in the secondary switch, which provides 93-97[%] efficiency in the wide range of output voltage. Fuel cell simulator is implemented to show similar output characteristics to actual fuel cell. Appropriate dead time td enables soft switching to the range where the peak value of excitation current in a high frequency transformer is in accordance with current in the primary circuit. Moreover, appropriate setting to serial inductance La reduces communication loss arisen at light-load generator and serge voltage arisen at a secondary switch and serial diode. Finally, TMS320C31 board and EPLD using PWM switching technique to act a single phase full-bridge inverter which is planed to make alternating current suitable for household.

• Journal of electromagnetic engineering and science
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• 제5권1호
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• pp.8-13
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• 2005

The InGaP/GaAs hetero-junction bipolar transistor(HBT) monolithic voltage-controlled dielectric resonator oscillator(VCDRO) is first demonstrated for a Ku-band low noise block down-converter(LNB) system. The on-chip voltage control oscillator core employing base-collector(B-C) junction diodes is proposed for simpler frequency tuning and easy fabrication instead of the general off-chip varactor diodes. The fabricated VCDRO achieves a high output power of 6.45 to 5.31 dBm and a wide frequency tuning range of ]65 MHz( 1.53 $\%$) with a low phase noise of below -95dBc/Hz at 100 kHz offset and -115 dBc/Hz at ] MHz offset. A]so, the InGaP/GaAs HBT monolithic DRO with the same topology as the proposed VCDRO is fabricated to verify that the intrinsic low l/f noise of the HBT and the high Q of the DR contribute to the low phase noise performance. The fabricated DRO exhibits an output power of 1.33 dBm, and an extremely low phase noise of -109 dBc/Hz at 100 kHz and -131 dBc/Hz at ] MHz offset from the 10.75 GHz oscillation frequency.

• 한국산학기술학회논문지
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• 제11권12호
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• pp.4975-4983
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• 2010

본 논문은 전력전자회로에서 많이 사용되고 있는 가장 범용적이고 강력한 시뮬레이터인 PSPICE와 MATLAB에 적용하여 소자를 모델링하여 보다 쉽게 이해하고, 다양한 제어기술을 적용시킬 수 있도록 미시적인 IGBT, 거시적인 IGBT, PWM 발생기 그리고 유도 전동기를 라이브러리화 하여 모델링의 타당성을 해석하였다. 미시적인 IGBT 모델의 소자특성을 실험을 통해 모델링의 정확성을 입증하였으며, 거시적인 IGBT모델은 사이클로 컨버터와 유도 전동기의 부하를 가진 전압형 PWM 인버터에 적용시켜 시뮬레이션 하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1528.1-1529
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• 2011

Scribing the transparent conductive oxide(TCO) is an essential technology for the large scaled dye-sensitized solar cell(DSC) and the commercialization of the DSC. Laser systems are most used for scribing technology due to their precision. However, it is difficult to generalize systems because most systems are large and heavy. In this study, we tried to simplificate the Nd:YAG laser system for scribing TCO of the DSC by using switched mode power supply(SMPS) technique. The continuous conduction mode booster converter topology is applied and MC34262 power factor controller is used for the variable frequency control. Finally, SMPS circuit which specifications are 400W of capacity, 400V DC output and 98% of efficiency is fabricated. And it is demonstrated that the scribing TCO is completed by the Nd:YAG laser using this SMPS circuit.

• 조명전기설비학회논문지
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• 제19권4호
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• pp.91-97
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• 2005

산업화로 인버터, 컨버터, 스위칭 전원공급기, 모터와 같은 비선형 장치들이 늘어가고 있다. 그러나 컴퓨터와 전기장치 등과 같은 전력품질에 민감한 부하의 사용이 빠르게 확산되어 왔다. 게다가 전력품질 문제와 실시간 전력품질 모니터링은 산업과 빌딩에서 시스템의 지능제어로써 관심이 증대되고 있는 문제 중에 하나이다. 그중 하나인 전력선통신을 이용한 전력품질 모니터링 시스템은 새로운 선로가 없이도 전력품질 정보를 보내고 받을 수 있는 큰 장점을 가지고 있다. 본 논문에서는 IEEE Std. 1159의 분류에 따라 전력품질 문제를 측정하는 알고리즘의 개발과 보드를 제작하고 이를 전력선통신을 이용하여 모니터링하는 시스템을 구현하였다.

• Journal of Power Electronics
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• 제14권2호
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• pp.226-236
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• 2014

A new active LED driver with high power factor (PF) and low total harmonic distortion (THD) compatible with a rapid-start ballast is proposed. An LC input filter is attached to the ballast to increase PF and reduce THD. A boost converter is then installed to regulate the LED current, where an unstable operating region has been newly identified. The unstable region is successfully stabilized by feedback control with two zeroes. The extremely high overall system of the 10th order is completely analyzed by the newly introduced phasor transformed circuits in static and dynamic analyses. Although a small DC capacitor is utilized, the flicker percentage of the LED is drastically mitigated to 1% by the fast controller. The proposed LED driver that employs a simple controller with a start-up circuit is verified by extensive experiments whose results are in good agreement with the design.

• Journal of Power Electronics
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• 제16권4호
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• pp.1483-1493
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• 2016

Multiple parallel inverters have multiple resonant frequencies that are influenced by many factors. This often results in stability and power quality problems. This paper develops a multiple input multiple output model of grid-connected inverter systems using a closed-loop transfer function. The influence factors of the resonant characteristics are analyzed with the developed model. The analysis results show that the resonant frequency is closely related to the number, type and composition ratio of the parallel inverters. To suppress resonance, a scheme based on virtual impedance is presented, where the virtual impedance is emulated in the vicinity of the resonance frequency. The proposed scheme needs one inverter with virtual impedance control, which reduces the design complexity of the other inverter controllers. Simulation and experimental tests are carried out on two single phase converter-based setups. The results validate the correctness of the model, the analytical results and the resonant suppressing scheme.

• Journal of Electrical Engineering and Technology
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• 제10권4호
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• pp.1389-1399
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• 2015

This research suggests maximum power point tracking (MPPT) for the solar photovoltaic (PV) power scheme using a new constant voltage (CV) fractional order incremental conductance (FOINC) algorithm. The PV panel has low transformation efficiency and power output of PV panel depends on the change in weather conditions. Possible extracting power can be raised to a battery load utilizing a MPPT algorithm. Among all the MPPT strategies, the incremental conductance (INC) algorithm is mostly employed due to easy implementation, less fluctuations and faster tracking, which is not only has the merits of INC, fractional order can deliver a dynamic mathematical modelling to define non-linear physiognomies. CV-FOINC variation as dynamic variable is exploited to regulate the PV power toward the peak operating point. For a lesser scale photovoltaic conversion scheme, the suggested technique is validated by simulation with dissimilar operating conditions. Contributions are made in numerous aspects of the entire system, including new control algorithm design, system simulation, converter design, programming into simulation environment and experimental setup. The results confirm that the small tracking period and practicality in tracking of photovoltaic array.