Analyses of MPPT algorithms in real test conditions

Maximum Power Point Tracking (MPPT) algorithms are of major importance for optimized yield in gridconnected PV systems. Many algorithms have been investigated. However, most of the works compare these algorithms based on a literature review or on simulation. This paper presents an experimental analysis of MPPT techniques: two of the simplest (Perturb & Observe and Incremental Conductance) and two of the most complex (Fuzzy Logic Controller and Particle Swarm Optimization). The results are carried out in real test conditions, with and without shadow. The power converter is based on a boost converter and a voltage source inverter. The control is implemented using Simulink® and dSPACE 1103 real-time controller board. Moreover, the MPPT techniques of three commercial string inverters are also analysed.info:eu-repo/semantics/publishedVersio

Maximum Power Point Tracking on the Alternative Current Side for Photovoltaic Applications

This paper represents an innovative Maximum Power Point tracking method. In this method which is named as “AC Side MPPT” as understood from the name control and switching will be realized at the AC side of the inverter. At the AC side a Perturb and Observe (P/O) method is implemented.Perturbation is realized as changing the amplitude of the AC output voltage with a ratio of ±20% of the nominal value. By this way the voltage of the solar panels is increased or decreased until the Maximum Power Point is captured. By means of this method, DC/DC converter does not deal with MPPT process, so the only function of the converter will be the regulation of the input. The output of the DC/DC converter always has a constant voltage value (800 VDC). By this way voltage ripples caused by the MPPT control and switching are not formed and this leads to utilizing of small sized semi conductor and passive components. Small sized components mean large W/cm3 ratios. Other power electronic modules of the inverter have the large W/cm3 ratio objectives. AC Side MPPT Method will be one of the tools which serve the realization of this purpose.Bu çalışmada yenilikçi maksimum güç noktası takip (MPPT) yöntemi sunulmuştur. Alternatif Akım (AC) tarafında maksimum güç noktası takibi olarak adlandırılan bu yöntemde, eviricinin çıkış tarafında (AC) kontrol işlemi yapılmaktadır. AC tarafta kontrol işlemi için değiştir ve gözlemle (P/O) algoritması kullanılmıştır. P/O algoritması ile AC çıkış geriliminin genliği, nominal gerilimin ±% 20'si oranında değiştirilerek gerçekleştirilmektedir. Bu yolla, güneş panellerinin (PV) gerilimi maksimum güç noktası bulunana kadar arttırılmakta ya da azaltılmaktadır. AC tarafta kontrol yöntemi ile DC/DC dönüştürücü MPPT işlemi yapmayacağından dönüştürücünün tek işlevi evirici giriş geriliminin düzenlenmesi olacaktır. DC/DC dönüştürücünün çıkış gerilimi her zaman sabit 800 VDC değerine sahiptir. Bu sayede, MPPT kontrolü ve anahtarlamadan kaynaklanan gerilim dalgalanmaları oluşmamakta ve buda küçük boyutlu (büyük W/cm3 oranı) yarı iletken ve pasif devre elemanlarının kullanımına yol açmaktadır. Sürücünün diğer güç elektroniği modülleri, büyük W/cm3 oranına sahiptir. AC tarafta MPPT yöntemi, bu amacın gerçekleştirilmesine hizmet eden araçlardan biri olacaktır

Standalone Photovoltaic Power Stabilizer Using Double Series Connected Converter in Sudden Cloud Condition

Renewable energy is clean energy that cannot harm the environment in its way, especially on standalone photovoltaic electricity generation. The only problem with renewable energy electricity generation is the intermittency and its instability in power quality and power efficiency. Power system stability in renewable energy is essential during the real environmental case problem such as the sudden cloud. The sudden cloud, known for its ability to decrease solar irradiance input, depends on how thick and big the cloud is. Several attempts had been tried to increase renewable energy power system stability, including modifying its maximum power point tracker with a new algorithm such as perturb and observe. This paper discussed an improved way of maintaining renewable energy power system stability using perturb and observe Algorithm in a double series-connected Converter as the current and power stabilizer. The results show that the current overshoot has decreased by 65,336%, and the current sudden cloud undershoot decreased by 10,529%. Power overshoot also decreased by 43,685%, and the power of sudden cloud undershoot has decreased by 7,133%

Quasi Z-Source Inverter as MPPT on Renewable Energy using Grey Wolf Technique

Z-Source Inverter (ZSI) is famous power converter who has capability to deal with voltage sags, improved power factor and wide voltage range of output. Quasi Z Source Inverter (QZSI) is the modern ZSI who has continuous current of input and can reduce stress of the passive component. This paper proposes simple boost QZSI circuit as Maximum Power Point Tracking (MPPT) using Grey Wolf Optimization (GWO) algorithm in photovoltaic system. Grey Wolf algorithm has been compared with the Perturb and Observed (P&O) technique for gaining the maximum power from the sun. Both techniques can get the optimum power of solar panel not only at constant sun light condition but also under varying irradiance levels. The value of average power obtained from GWO technique is greater than P&O. Although the value of solar radiation changes, the output voltage remains stable and both algorithms carry on obtaining optimal power of the sun

Standalone Photovoltaic Power Stabilizer Using Double Series Connected Converter in Sudden Cloud Condition

Renewable energy is clean energy that cannot harm the environment in its way, especially on standalone photovoltaic electricity generation. The only problem with renewable energy electricity generation is the intermittency and its instability in power quality and power efficiency. Power system stability in renewable energy is essential during the real environmental case problem such as the sudden cloud. The sudden cloud, known for its ability to decrease solar irradiance input, depends on how thick and big the cloud is. Several attempts had been tried to increase renewable energy power system stability, including modifying its maximum power point tracker with a new algorithm such as perturb and observe. This paper discussed an improved way of maintaining renewable energy power system stability using perturb and observe Algorithm in a double series-connected Converter as the current and power stabilizer. The results show that the current overshoot has decreased by 65,336%, and the current sudden cloud undershoot decreased by 10,529%. Power overshoot also decreased by 43,685%, and the power of sudden cloud undershoot has decreased by 7,133%

A maximum power point tracking of a photovoltaic system connected to a three-phase grid using a variable step size perturb and observe algorithm

Purpose. The production of electricity from solar energy is necessary because of the global consumption of this energy. This article’s study is based on increased energy extraction by improving maximum power point tracking (MPPT). From different MPPT techniques proposed, the perturb and observe (P&O) technique is developed because of its low implementation cost and ease of implementation. Methods. A modified variable step-size P&O MPPT algorithm is investigated which uses fuzzy logic to automatically adjust step-size to better track maximum power point, compared with the conventional fixed step-size method. The variable step P&O improves the speed and the tracking accuracy. This controller is implemented on a boost DC-DC power converter to track the maximum power point. The suggested controlled solar energy system includes a boost converter, a voltage-source inverter, and a grid filter. The control scheme of a three-phase current-controlled pulse-width modulation inverter in rotating synchronous coordinate d-q with the proposed MPPT algorithm and feed-forward compensation is studied. Results. The photovoltaic grid-connected system controller employs multi-loop control with the filter inductor current of the inverter in the inner loop to achieve a fast dynamic response and the outer loop to control bus voltage for MPPT, the modeling, and control of three phase grid connected to photovoltaic generator is implemented in the MATLAB/Simulink environment and validated by simulation results.Мета. Виробництво електроенергії із сонячної енергії необхідне через глобальне споживання цієї енергії. Дослідження цієї статті ґрунтується на збільшенні вилучення енергії за рахунок покращення відстеження точки максимальної потужності (MPPT). З різних запропонованих методів MPPT був розроблений метод збурення та спостереження (P&O) через його низьку вартість реалізації та простоту реалізації. Методи. Досліджується модифікований алгоритм P&O MPPT зі змінним розміром кроку, який використовує нечітку логіку для автоматичного налаштування розміру кроку для кращого відстеження точки максимальної потужності порівняно із звичайним методом фіксованого розміру кроку. Змінний крок P&O підвищує швидкість та точність відстеження. Цей контролер реалізований на перетворювачі, що підвищує потужності постійного струму для відстеження точки максимальної потужності. Пропонована керована сонячна енергетична система включає підвищуючий перетворювач, інвертор джерела напруги і мережевий фільтр. Досліджується схема управління трифазним струмокерованим інвертором з широтно-імпульсною модуляцією в синхронній координаті, що обертається, d-q із запропонованим алгоритмом MPPT і попереджувальною компенсацією. Результати. Контролер фотоелектричної системи, підключеної до мережі, використовує багатоконтурне керування зі струмом індуктора фільтра інвертора у внутрішньому контурі для досягнення швидкого динамічного відгуку та зовнішнім контуром для керування напругою шини для MPPT, моделювання та керування трифазною мережею. підключений до фотогальванічного генератора, реалізований у середовищі MATLAB/Simulink та підтверджений результатами моделювання

A Review on Maximum Power Point Tracking (MPPT) Technique for PV Power Generation System

The growing concern on environmental issues caused by fossil fuels and, indeed, on the availability of such energy resources in a long-run basis have settled the ground for the spreading of the so-called green energy sources. Among them, photovoltaic energy stands out due to the possibility of turning practically any household into a micro power plant. One important aspect about this source of energy is that practical photovoltaic generators are equipped with maximum power point tracking (MPPT) systems. Currently, researchers are focused on developing MPPT algorithms for partial shaded panels. In this paper review is presented on the emerging topologies for PV applications that could be used in the generation of new smart inverters

Optimization And Design Of Photovoltaic Micro-inverter

To relieve energy shortage and environmental pollution issues, renewable energy, especially PV energy has developed rapidly in the last decade. The micro-inverter systems, with advantages in dedicated PV power harvest, flexible system size, simple installation, and enhanced safety characteristics are the future development trend of the PV power generation systems. The double-stage structure which can realize high efficiency with nice regulated sinusoidal waveforms is the mainstream for the micro-inverter. This thesis studied a double stage micro-inverter system. Considering the intermittent nature of PV power, a PFC was analyzed to provide additional electrical power to the system. When the solar power is less than the load required, PFC can drag power from the utility grid. In the double stage micro-inverter, the DC/DC stage was realized by a LLC converter, which could realize soft switching automatically under frequency modulation. However it has a complicated relationship between voltage gain and load. Thus conventional variable step P&O MPPT techniques for PWM converter were no longer suitable for the LLC converter. To solve this problem, a novel MPPT was proposed to track MPP efficiently. Simulation and experimental results verified the effectiveness of the proposed MPPT. The DC/AC stage of the micro-inverter was realized by a BCM inverter. With duty cycle and frequency modulation, ZVS was achieved through controlling the inductor current bi-directional in every switching cycle. This technique required no additional resonant components and could be employed for low power applications on conventional full-bridge and half-bridge inverter topologies. Three different current mode control schemes were derived from the basic theory of the proposed technique. They were referred to as Boundary Current Mode (BCM), Variable Hysteresis Current Mode (VHCM), and Constant Hysteresis Current Mode (CHCM) individually in this paper with their advantages and disadvantages analyzed in detail. Simulation and experimental iv results demonstrated the feasibilities of the proposed soft-switching technique with the digital control schemes. The PFC converter was applied by a single stage Biflyback topology, which combined the advantages of single stage PFC and flyback topology together, with further advantages in low intermediate bus voltage and current stresses. A digital controller without current sampling requirement was proposed based on the specific topology. To reduce the voltage spike caused by the leakage inductor, a novel snubber cell combining soft switching technique with snubber technique together was proposed. Simulation and experimental waveforms illustrated the same as characteristics as the theoretical analysis. In summary, the dissertation analyzed each power stage of photovoltaic micro-inverter system from efficiency and effectiveness optimization perspectives. Moreover their advantages were compared carefully with existed topologies and control techniques. Simulation and experiment results were provided to support the theoretical analysis