• 전자공학회논문지
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• 제50권6호
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• pp.105-113
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• 2013

본 논문에서는 0.5V 이하의 낮은 전압을 출력하는 초소형 PV(photovoltaic) 셀을 이용한 MPPT(Maximum Power Point Tracking) 제어 기능을 갖는 마이크로 빛에너지 하베스팅 시스템을 제안한다. MPPT 제어는 PV 셀의 개방전압과 MPP(Maximum Power Point) 전압간의 비례관계를 이용하여, 파일럿(pilot) PV 셀로 하여금 주(main) PV 셀의 MPP를 실시간 추적할 수 있도록 설계하였다. 제안된 회로는 0.18um CMOS 공정으로 설계되었으며, 칩 면적은 부하단 전하펌프와 패드를 포함하여 $900um{\times}1370um$이다. 제작된 칩을 측정한 결과 설계된 회로가 빛 세기의 변화에 따른 MPP 전압 변화를 실시간 트래킹하는 것을 확인하였다. 또한 MPPT 제어기능을 적용했을 때 부하가 큰 경우에도 MPP 근처의 전압을 부하에 공급함으로써 MPPT 제어기능을 적용하지 않았을 때에 비해 더 많은 전력을 부하로 공급하는 것을 확인하였다. 기존의 마이크로 빛에너지 하베스팅 회로에 비해 제안된 회로는 제어회로 구동을 위해 미리 충전된 배터리가 필요하지 않기 때문에 배터리를 사용하지 않는 초소형 자가발전 시스템에 적합하다.

• 한국전자통신학회논문지
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• 제8권7호
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• pp.1039-1048
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• 2013

일반적으로 벅 컨버터 제어기는 컨버터의 출력 전압을 제어하도록 설계하지만, 태양광발전시스템에서의 벅 컨버터 제어기는 설계 방식을 달리 구분해야 한다. 본 논문에서는 MPPT(Maximum Power Point Tracking)을 위하여 벅 컨버터의 입력 전압(태양광전지의 출력 전압)을 제어한다고 가정하였다. 또한, 컨버터의 입력 전압을 제어하기 위한 새로운 벅 컨버터 모델을 제시한다. 이 컨버터 모델은 최대전력점(MPP)에서 동작점을 두어 선형화한 태양광전지의 모델을 포함하며, 모델의 타당성을 검증하기 위하여 대신호와 소신호로 나누어 분석한다. 또한 일반적인 선형제어기를 설계하였을 때, 제어 가능성을 분석하여 검증한다.

• KIEAE Journal
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• 제14권2호
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• pp.21-28
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• 2014

This paper provides the up to date review of the shading effects on PV module performance and the associated detection algorithm related to the maximum power point tracking. It includes the brief explanations of the MMP variations due to the shading occurrence on the PV modules. Review of experimental and simulation studies highlighting the significant impacts of shading on PV efficiencies were presented. The literature indicates that even the partial shading of a single cell can greatly drop the entire module voltage and power efficiency. The MMP tracking approaches were also reviewed in this study. Both conventional and advanced soft computing methods such as ANN, FLC and EA were described for the proper tracking of MMP under shaded conditions. This paper would be the basic source and the comprehensive information associated with the shading effects and relevant MPP tracking technique.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2011년도 추계학술대회
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• pp.425-428
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• 2011

본 논문에서는 간단한 Maximum Power Point Tracking이 적용된 micro-scale의 빛에너지 하베스팅 회로를 제안한다. 에너지 변환기로는 온칩 PV cell 대신 이와 비슷한 출력을 하는 초소형 PV cell을 사용하였다. 적용된 MPPT는 PV cell의 개방전압($V_{OC}$)와 MPP전압($V_{MPP}$)과의 관계를 이용하였고 이는 pilot PV cell을 이용함으로써 가능하였다. 설계결과 MPPT control을 적용했을 때 부하가 큰 경우에도 대략 $V_{MPP}$ 전압을 부하에 공급함으로써 부하에 연결된 회로가 정상적으로 동작하는 것을 확인하였다. 제안된 회로는 TSMC 0.18um CMOS 공정으로 설계되었다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제16권4호
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• pp.281-292
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• 2016

The proposed scheme is based on the modified perturb and observe (P&O) algorithm combined with the sliding mode technique. A modified P&O algorithm based sliding mode controller is developed to study the effects of partial shade, temperature, and insolation on the performance of maximum power point tracking (MPPT) used in photovoltaic (PV) systems. Under partially shaded conditions and temperature, the energy conversion efficiency of a PV array is very low, leading to significant power losses. Consequently, increasing efficiency by means of MPPT is particularly important. Conventional techniques are easy to implement but produce oscillations at MPP. The proposed method is applied to a model to simulate the performance of the PV system for solar energy usage, which is compared to the conventional methods under non-uniform insolation improving the PV system utilization efficiency and allowing optimization of the system performance. The modified perturb and observe sliding mode controller successfully overcomes the issues presented by non-uniform conditions and tracks the global MPP. Compared to MPPT techniques, the proposed technique is more efficient; it produces less oscillation at MPP in the steady state, and provides more precise tracking.

• Journal of Power Electronics
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• 제12권1호
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• pp.172-180
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• 2012

Z-source inverters (ZSI) are used to realize both DC voltage boost and DC-AC inversion in single stage with a reduced number of power switching devices. A traditional MPPT control algorithm provides a shoot-through interval which should be inserted in the switching waveforms of the inverter to output the maximum power to the Z-network. At this instant, the voltage across the Z-source capacitor is equal to the output voltage of a PV array at the maximum power point (MPP). The control of the Z-source capacitor voltage beyond the MPP voltage of a PV array is not facilitated in traditional MPPT algorithms. This paper presents a unified MPPT control algorithm to simultaneously achieve MPPT as well as Z-source capacitor voltage control. Development and implementation of the proposed algorithm and a comparison with traditional results are discussed. The effectiveness of the proposed unified MPPT control strategy is implemented in Matlab/Simulink software and verified by experimental results.

• 한국정보기술학회논문지
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• 제17권9호
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• pp.19-30
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• 2019

태양광 발전은 일사량 및 온도 등 외부변화에 따른 안정적이고 효율적인 최대 전력 출력 전력점을 추적하기 위한 MPPT 알고리즘이 필요하다. 본 연구는 인공 신경망을 이용하여 기존 MPPT 알고리즘보다 신속하게 MPP를 추적할 수 있는 모델을 구현하였다. 제안 모델은 인공 신경망의 학습 데이터를 위해 다양한 일사량과 온도의 조합에 대해서 기존 MPPT 알고리즘으로 MPP의 전류와 전압을 찾았다. 획득한 MPP 데이터는 입력 노드를 일사량과 온도로 출력 노드를 전류와 전압으로 하여 학습하였다. 실험결과 일사량과 온도 변화가 있는 0~0.3t 구간에서 추적시간은 기존 알고리즘인 P&O와 InC 그리고 Fuzzy는 각각 잘못된 계산식t, 0.49t 그리고 0.4076t이였으며, 제안 모델은 0.32511t로서 기존 알고리즘 보다 0.1t 이상 신속하게 MPP를 추적하였다.

• 조명전기설비학회논문지
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• 제26권8호
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• pp.27-34
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• 2012

This paper proposes variable incremental conductance(IC) algorithm for maximum power point tracking(MPPT) control of photovoltaic. The conventional perturbation & observation(PO) and IC MPPT control algorithm generally uses fixed step size. A small step size reduces a tracking error in the steady state but slows a tracking speed in the transient state. Also, a large step size is fast a tracking speed but increases a tracking error. Therefore, this paper proposes variable IC MPPT algorithm that adjust automatically step size according to operating conditions. To improve a tracking speed and accuracy, when operating point is far from the maximum power point(MPP), the step size uses maximum value and when a operating point is near from the MPP, the step size uses variable step size that adjust according to slope of P-V curve. The validity of MPPT algorithm proposed in this paper prove through compare with conventional PO and IC MPPT algorithm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.958-959
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• 2015

This paper proposes adaptive incremental conductance(A-IC) algorithm for maximum power point tracking(MPPT) control of photovoltaic. Conventional Perturbation & Observation(PO) and IC MPPT control algorithm generally uses fixed step size. A small fixed step size will cause the tracking speed to decrease and tracking accuracy of the MPP will decrease due to large fixed step size. Therefore, this paper proposes N-IC MPPT algorithm that adjust automatically step size according to operating conditions. To improve tracking speed and accuracy, when operating point is far from maximum power point(MPP), step size uses maximum value and when operating point is near from MPP, step size uses variable step size that adjust according to slope of P-V curve. The validity of MPPT algorithm proposed in this paper prove through compare with conventional IC MPPT algorithm.

• 통합자연과학논문집
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• 제15권3호
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• pp.99-110
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• 2022

Solar photovoltaic (PV) system shows a non-linear current (I) -voltage (V) characteristics, which depends on the surrounding environment factors, such as irradiance, temperature, and the wind. Solar PV system, with current (I) - voltage (V) and power (P) - Voltage (V) characteristics, specifies a unique operating point at where the possible maximum power point (MPP) is delivered. At the MPP, the PV array operates at maximum power efficiency. In order to continuously harvest maximum power at any point of time from solar PV modules, a good MPPT algorithms need to be employed. Currently, due to its simplicity and easy implementation, Perturb and Observe (P&O) algorithms are the most commonly used MPPT control method in the PV systems but it has a drawback at suddenly varying environment situations, due to constant step size. In this paper, to overcome the difficulties of the fast changing environment and suddenly changing the power of PV array due to constant step size in the P&O algorithm, least mean Square (LMS) methods is proposed together with P&O MPPT algorithm which is superior to traditional P&O MPPT. PV output power is predicted using LMS method to improve the tracking speed and deduce the possibility of misjudgment of increasing and decreasing the PV output. Simulation results shows that the proposed MPPT technique can track the MPP accurately as well as its dynamic response is very fast in response to the change of environmental parameters in comparison with the conventional P&O MPPT algorithm, and improves system performance.