• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.1
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• pp.106-111
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• 2007

In this study, we designed a digital fuzzy logic controller based on FPGA and microprocessor for MPPT of the sofar power generation system. A fuzzy algorithm to control the power tracking function of a boost converter has been built into the FPGA, and applied to the small scaled solar power generation system. The embodied controller showed a stable operation characteristic with the small output voltage ripple for the intensity change of solar radiation. This result proves that the implementation of the power tracking controller using FPGA is an effective way compared to the existing one using microprocessor.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.346-349
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• 2004

The design of DC-DC converters for power electronic interfaces in power management systems for Hybrid Electric Vehicle (HEV) is a very challenging task. In this paper, the considered topology is the hi-directional buck-boost converter and inverter system. If we make the converter side DC link current the same as the inverter side DC link current in a converter-inverter system, no current will flow through the BC link capacitor and as a result, no DC link voltage variation occurs. This leads to the possibility of reducing small th size of DC link capacitors which are expensive, bulky. Therefore we propose the converter current controller which can manage to match inverter and converter current at the DC link.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.81-82
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• 2012

본 논문은 고효율 획득 및 입력전류 리플 저감을 위한 3상 부스트 컨버터의 동작 알고리즘을 제안한다. 입력전압별로 인덕터 전류에 따른 투자율 감소를 고려하여 DCM 및 BCM 동작시의 효율과 입력 전류 리플을 수식적으로 분석한다. 이에 따라 3상 부스트 컨버터를 경계 도통 모드+불연속 도통 모드의 혼합 모드에서 동작시키고 타당성을 실험을 통해 검증한다.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.93-94
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• 2012

본 논문에서는 효율 향상과 부피저감을 위한 전기자동차용 3.7kW급 비절연형 탑재형 충전기를 소개하고, 강압영역에서의 성능 개선을 위한 알고리즘을 제안한다. 제안한 충전기 토폴로지는 Cascaded Buck-Boost 컨버터로 두개의 Pole로 구성되어 있으며, 강압영역에서 제어는 기존의 제어 방식과 다르게 두 개의 Pole을 동시에 제어하지 않고 각각을 제어하여 인덕터의 전류 리플을 저감하여 충전효율을 증가 시킬 수 있다. 제안한 시스템 및 알고리즘은 실험을 통해 검증한다.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.93-96
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• 1999

Solar cell generate DC power from sunlight whose power is different at any instance according to condition of variables : insolation and temperature. In order to improve the system utility factor and efficiency of energy conversion, it is desirable to operate the PV system at maximum power point of solar cell under different condition. In this paper, Boost chopper is controlled it output voltage with a new discrete control algorithm for MPPT. PWM signal of DC-DC converter are generated with a 89C51 microcontroller. Switching frequency of DC-DC converter is set at 10KHz. Simulation and experimental results show that the PV system studied in this paper is always operated at maximum power point under different maximum power point of solar cells having stabilized output voltage waveform with relatively small ripple component

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.238-241
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• 1995

In this paper, a new Maximum Power Point Tractor (MPPT) using Fuzzy Controller is proposed to improve energy convention efficiency. Temperature compensation effect means the photovoltaic voltage is change in condition irradiation, temperature and etc. Fuzzy algorithm is applied to control Boost MPPT converter by Temperature compensation effect. Temperature compensation range is $-40\sim+100^{\circ}C$.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1142-1143
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• 2008

As well known, the maximum power point tracking (MPPT) is an important role in photovoltaic (PV) power systems. MPPT finds and maintains the operation of PV at the maximum power point when the irradiation and cell-temperature change. In this paper, the studied system includes a PV array, a Buck-Boost DC/DC converter, a DC/AC inverter and it is connected to the three phase power system. The solar array operates as a non-linear voltage source. The P&O algorithm with power feed-back is used to control the operating point of PV array at the maximum power point. The effects of irradiation and cell-temperature on the dynamic responses are also considered.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.966-971
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• 1998

The studies on the photovoltaic system are extensively exhaustible and broadly available resourse as a future energy supply. In this paper, a new maximum power point tracker(MPPT) using neural network theory is proposed to improve energy conversion efficiency. The boost converter and neural network controller(NNC) were employed so that the operating point of solar cell was located at the Maximum Power Point. And the back propagation algorithm with one input layer of two inputs(E, CE) and output layer(cnntrol value) was applied to train a neural network. Simulation and experimental results show that the performance of NNC in MPPT of photovoltaic array is better than that of controller based upon the Hill Climbing Method.

• Proceedings of the Korean Information Science Society Conference
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• 2008.06c
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• pp.565-568
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• 2008

본 논문은 RGB 24bit 컬러 영상으로 전달되는 카메라 원영상에 대해 사람의 얼굴을 안정적으로 감지할 수 있는 알고리즘을 제시한다. RGB 입력영상을 HSI 기반의 컬러모델로 변환하여 피부 색상을 추출하고 그리드 영상을 기반으로 CCL (Connected-Component Labeling) 알고리즘을 적용하여 피부 블럽을 검출한 뒤, 아다부스트 알고리즘을 이용하여 얼굴 영역과 얼굴이 아닌 다른 피부 영역을 구분한다. 제안방법은 일반적으로 얼굴 감지를 위하여 폭넓게 사용되고 있는 아다부스트 알고리즘만을 적용하였을 때보다 얼굴감지 오류를 줄일 수 있다.

• Journal of Biomedical Engineering Research
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• v.17 no.3
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• pp.305-312
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• 1996

A new three dimensional fractal coding is proposed with a perceptually enhanced matching. Since most of medical images (e.g. computed tomoyaphy or magnetic resonance images) have three dimensional characters, searching regions are extended to adjacent slices. For a perceptually enhanced matching, a high frequency boost filter is used for pre-filtering images to be encoded, and a least mean square error matching is applied to the edge enhanced Images rather than the original images. From simulation with magnetic resonance images($255\times255$, 8bits/pixel), reconstructed images by the proposed compression algorithm show much improved subjective image quality with higher peak signnal-to-noise ratio compared to those by existing fractal coding algorithms at compression ratios of about 10.