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1

Enhancing MPPT in partially shaded PV modules: a novel approach using adaptive reinforcement learning with neural network architecture

Leelavathi M., Suresh Kumar V.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2024

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Vol. 72, nr 4

art. no. e150112

EN

The occurrence of partial shading in solar power systems presents a substantial challenge with widespread implications, sparking extensive research, notably in the field of maximum power point tracking (MPPT). This study emphasizes the critical process of accurately tracking the maximum power points with the characteristic curves of photovoltaic (PV) modules under real-time, diverse partial shading patterns. It explores the various stages of the tracking process and the methodologies employed for optimization. While conventional methods show effectiveness, they often fall short in swiftly and accurately tracking maximum power points with minimal errors. To address this limitation, this research introduces a novel machine learning approach known as adaptive reinforcement learning with neural network architecture (ARL-NNA) for MPPT. The results obtained from ARL-NNA are compared with existing algorithms using the same experimental data. Furthermore, the outcomes are validated through different factors and processing time measurements. The findings conclusively demonstrate the efficacy and superiority of the proposed algorithm in effectively tracking maximum power points in PV characteristic curves, providing a promising solution for optimizing solar energy generation in partial shading patterns. This study significantly impacts various realms of electrical engineering including power engineering, power electronics, industrial electronics, solid-state electronics, energy technology, and other related field of engineering and technology.

2

Control of a photovoltaic system by sliding mode based on backstepping

Bouchriha Ilhem, Ghanem Ali Ben, Nouri Khaled

Przegląd Elektrotechniczny

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2023

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R. 99, nr 6

192--195

EN

In this article we have studied photovoltaic systems which are non-linear systems. Due to variations in the current-voltage characteristics of PV systems. In fact, we have described the sliding mode method and then we have combined it with the backstepping method. We have applied it to a well-determined PV system. shows that the sliding mode method based on backstepping is more efficient than that of the basic sliding mode.

PL

W tym artykule badaliśmy systemy fotowoltaiczne, które są systemami nieliniowymi. Ze względu na różnice w charakterystyce prądowo-napięciowej systemów fotowoltaicznych. W rzeczywistości opisaliśmy metodę trybu ślizgowego, a następnie połączyliśmy ją z metodą cofania. Zastosowaliśmy to do dobrze określonego systemu fotowoltaicznego. pokazuje, że metoda trybu ślizgowego oparta na krokach wstecznych jest bardziej wydajna niż metoda trybu ślizgowego podstawowego.

3

Compensation of harmonics using a shunt active power filter powered by a photovoltaic source

Khelil Cherfi Mohamed, Gacemi Abderrezak, Morsli Abdelkader, Tlemçani Abdelhalim

Przegląd Elektrotechniczny

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2023

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R. 99, nr 6

69--73

EN

Electronic devices feature non-linear switching functionality, current distortion gives rise to harmonics that shorten the life of devices and damage electrical networks, causing malfunctions and overheating. Mitigation of harmonics problems and improvement of power quality are necessary. The shunt active power filter reduces harmonics and greatly improves the sinusoidal shape of the current. This work presents a study with two different voltage sources of a two-level inverter applied to a shunt active power filter based on three phases connected to the grid, the first is a continuous direct source and the second is a photovoltaic source. Simulation results provided good efficiency of the SAPF with the photovoltaic system integration.

PL

Urządzenia elektroniczne posiadają funkcję przełączania nieliniowego, zniekształcenia prądu powodują powstawanie harmonicznych, które skracają żywotność urządzeń i niszczą sieci elektryczne, powodując awarie i przegrzewanie. Niezbędne jest łagodzenie problemów z harmonicznymi i poprawa jakości energii. Bocznikowy aktywny filtr mocy redukuje harmoniczne i znacznie poprawia sinusoidalny kształt prądu. W pracy przedstawiono badanie z dwoma różnymi źródłami napięcia dwupoziomowego falownika zastosowanego do bocznikowego filtra mocy czynnego opartego na trzech fazach podłączonych do sieci, przy czym pierwsza jest ciągłym źródłem bezpośrednim, a druga jest źródłem fotowoltaicznym. Wyniki symulacji zapewniły dobrą wydajność SAPF z integracją systemu fotowoltaicznego.

4

Advanced topology for grid-connected photovoltaic system based PWM rectifier

Laib Hichem, Sakri Djamel, Barra Kamel

Przegląd Elektrotechniczny

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2023

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R. 99, nr 4

266--272

EN

This paper proposes an advanced topology for grid-connected photovoltaic systems (GCPVS) based on sliding mode control (SMC). The proposed topology exploits the generation and regeneration modes of the three-phase PWM rectifier well suited for high power quality. In addition, it has the advantage of eliminating the inverter and the diode rectifier stages used in the classical structure and replacing them by a PWM rectifier. For maximum power point tracking (MPPT) of the PV generator, DC-Link voltage control and direct power control (DPC), a sliding mode controllers (SMC) are used in order to obtain high accuracy and fast dynamic response against meteorological and load variations. To verify the effectiveness of the control applied on the proposed topology, a wide simulation results are carried out under MATLAB-SIMULINK environment for different operating conditions that confirm the feasibility of the proposed topology.

PL

W artykule zaproponowano zaawansowaną topologię systemów fotowoltaicznych podłączonych do sieci (GCPVS) w oparciu o sterowanie trybem ślizgowym (SMC). Proponowana topologia wykorzystuje tryby generowania i regeneracji trójfazowego prostownika PWM dobrze przystosowanego do wysokiej jakości energii. Dodatkowo ma tę zaletę, że eliminuje stosowane w klasycznej konstrukcji stopnie falownika i prostownika diodowego i zastępuje je prostownikiem PWM. Do śledzenia maksymalnego punktu mocy (MPPT) generatora fotowoltaicznego, sterowania napięciem DC-Link i bezpośredniego sterowania mocą (DPC), stosowane są kontrolery trybu ślizgowego (SMC) w celu uzyskania wysokiej dokładności i szybkiej odpowiedzi dynamicznej na zmiany pogody i obciążenia . Aby zweryfikować skuteczność zastosowanego sterowania na proponowanej topologii, przeprowadza się szerokie wyniki symulacji w środowisku MATLAB-SIMULINK dla różnych warunków pracy, które potwierdzają wykonalność proponowanej topologii.

5

Robust estimation based nonlinear higher order sliding mode control strategies for PMSG-WECS

Nazir Awais, Khan Safdar Abbas, Khan Malak Adnan, Alam Zaheer, Khan Imran, Irfan Muhammad, Rehman Saifur, Nowakowski Grzegorz

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2023

|

Vol. 71, nr 5

art. no. e147063

EN

The wind energy conversion systems (WECS) suffer from an intermittent nature of source (wind) and the resulting disparity between power generation and electricity demand. Thus, WECS are required to be operated at maximum power point (MPP). This research paper addresses a sophisticated MPP tracking (MPPT) strategy to ensure optimum (maximum) power out of the WECS despite environmental (wind) variations. This study considers a WECS (fixed pitch, 3KW, variable speed) coupled with a permanent magnet synchronous generator (PMSG) and proposes three sliding mode control (SMC) based MPPT schemes, a conventional first order SMC (FOSMC), an integral back-stepping-based SMC (IBSMC) and a super-twisting reachability-based SMC, for maximizing the power output. However, the efficacy of MPPT/control schemes rely on availability of system parameters especially, uncertain/nonlinear dynamics and aerodynamic terms, which are not commonly accessible in practice. As a remedy, an off-line artificial function-fitting neural network (ANN) based on Levenberg-Marquardt algorithm is employed to enhance the performance and robustness of MPPT/control scheme by effectively imitating the uncertain/nonlinear drift terms in the control input pathways. Furthermore, the speed and missing derivative of a generator shaft are determined using a high-gain observer (HGO). Finally, a comparison is made among the stated strategies subjected to stochastic and deterministic wind speed profiles. Extensive MATLAB/Simulink simulations assess the effectiveness of the suggested approaches.

6

Maximum power point tracking techniques for low-cost solar photovoltaic applications – Part I: constant parameters and trial-and-error

Sutikno Tole, Subrata Arsyad Cahya, Pau Giovanni, Jusoh Awang, Ishaque Kashif

Archives of Electrical Engineering

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2023

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Vol. 72, nr 1

125--145

EN

The development of research on the maximum power point tracking (MPPT) controller has increased significantly in this decade. The MPPT technique, however, is still demanding because of the ease and simplicity of implementing tracking technique on the maximum power point (MPP). In this paper, MPPT techniques and their modifications from various literature are classified and examined in detail. The discussions are focused on the main objective of obtaining the best possible MPPT technique with the best results at a low cost. The assessment for the selection of MPPT techniques is based on assessments from the previous literature. The discussion of the MPPT technique assessment is divided into two parts. In Part I, the MPPT technique based on constant parameters, and trial-and-error will be discussed in detail, along with its algorithm development in recent times.

7

Maximum power point tracking techniques for low-cost solar photovoltaic applications – Part II: Mathematical Calculation and Measurement and Comparison, criteria on choices and suitable MPPT techniques

Sutikno Tole, Subrata Arsyad Cahya, Pau Giovanni, Jusoh Awang, Ishaque Kashif

Archives of Electrical Engineering

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2023

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Vol. 72, nr 2

299--322

EN

In the last decade, there has been a substantial surge in the advancement of research into the maximum power point tracking (MPPT) controller. The MPPT approaches, on the other hand, continue to be in high demand due to the ease and simplicity with which tracking techniques can be implemented on the maximum power point (MPP). Diverse MPPT approaches and their modifications from various literature are categorized and thoroughly explored in this work, which is divided into two sections. The discussions are centered on the primary goal of attaining the most extraordinary feasible MPPT technique that produces the best results at the lowest possible expense. In order to determine which MPPT approaches to use, evaluations from earlier literature are used to guide the decision. In this section, we will examine the evaluation of the MPPT technique in two sections. Previously, in Part I, we explored the MPPT techniques based on constant parameters and trial-and- error. Part II of this article will examine the MPPT technique, which is based on mathematical computation, measurement, and comparison, and the algorithm development that has occurred in recent years. Furthermore, this section’s assessment for selecting MPPT approaches is based on previous literature reviews. To aid with this selection, the following criteria for the MPPT approach are proposed: sensors and analog/digital requirements, costeffectiveness, simplicity, stability, efficiency, and tracking speed. This enables the reader to select the MPPT technique that is most appropriate for their application.

8

A photovoltaic system maximum power point tracking by using artificial neural network

Kumar Karri Hemanth, Rao Gadi Venkata Siva Krishna

Przegląd Elektrotechniczny

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2022

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R. 98, nr 2

33--38

EN

The electrical energy from the sun can be extracted using solar photovoltaic (PV) modules. This energy can be maximized if the connected load resistance matches that of the PV panel. In search of the optimum matching between the PV and the load resistance, the maximum power point tracking (MPPT) technique offers considerable potential. This paper aims to show how the modelling process of an efficient PV system with a DC load can be achieved using an artificial neural network (ANN) controller. This is applied via an innovative methodology, which senses the irradiance and temperature of the PV panel and produces an optimal value of duty ration for the boost converter to obtain the MPPT. The coefficients of this controller have been refined based upon previous data sets using the irradiance and temperature. A gradient descent algorithm is employed to improve the parameters of the ANN controller to achieve an optimal response. The validity of the PV system using the MPPT technique based on the ANN controller is further demonstrated via a series of experimental tests at different ambient conditions. The simulation results show how the MPPT technique based on the ANN controller is more effective in maintaining the optimal power values compared with conventional techniques.

PL

Energia elektryczna ze słońca może być pozyskiwana za pomocą modułów fotowoltaicznych (PV). Energię tę można zmaksymalizować, jeśli rezystancja podłączonego obciążenia jest zgodna z rezystancją panelu fotowoltaicznego. W poszukiwaniu optymalnego dopasowania między PV a rezystancją obciążenia, technika śledzenia punktu maksymalnej mocy (MPPT) oferuje znaczny potencjał. Niniejszy artykuł ma na celu pokazanie, w jaki sposób można osiągnąć proces modelowania wydajnego systemu fotowoltaicznego z obciążeniem DC przy użyciu kontrolera sztucznej sieci neuronowej (ANN). Jest to stosowane za pomocą innowacyjnej metodologii, która wykrywa natężenie promieniowania i temperaturę panelu fotowoltaicznego i wytwarza optymalną wartość współczynnika wypełnienia dla konwertera doładowania w celu uzyskania MPPT. Współczynniki tego kontrolera zostały udoskonalone w oparciu o poprzednie zestawy danych z wykorzystaniem natężenia promieniowania i temperatury. Algorytm opadania gradientu jest wykorzystywany do poprawy parametrów kontrolera ANN w celu uzyskania optymalnej odpowiedzi. Ważność systemu fotowoltaicznego wykorzystującego technikę MPPT opartą na sterowniku ANN jest dalej demonstrowana w serii testów eksperymentalnych w różnych warunkach otoczenia. Wyniki symulacji pokazują, w jaki sposób technika MPPT oparta na sterowniku ANN skuteczniej utrzymuje optymalne wartości mocy w porównaniu z technikami konwencjonalnymi.

9

Sliding Mode Control-Based MPPT and Output Voltage Regulation of a Stand-alone PV System

Manuel Nelson Luis, İnanç Nihat

Power Electronics and Drives

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2022

|

Vol. 7 (42)

159--173

EN

When it comes to reducing emissions caused by the generation of electricity, among different renewable energy sources, the solar energy gains prominence, due to its geographical availability, simplicity of implementation, and absence of physical moving parts. However, the performance of photovoltaic systems is dependent on environmental conditions. Depending on temperature and solar irradiation, the photovoltaic (PV) system has an operating point where maximum power can be generated. The techniques that are implemented to find this operating point are the so-called maximum power point tracking (MPPT) algorithms. Since weather conditions are variable in nature, the output voltage of the PV system needs to be regulated to remain equal to the reference. Most of the existing studies focus either on MPPT or on voltage regulation of the PV system. In this paper, the two-stage PV system is implemented so that both MPPT and voltage regulation are achieved simultaneously. Additionally, an improved version of the perturb and observe (P&O) algorithm based on artificial potential fields (APF), called APF-P&O, is presented. According to the results of the simulations carried out in MATLAB/Simulink software, the APF-P&O method is more efficient than the conventional method.

10

Switching strategies of single stage battery based microgrid

Ponnuru Sudhakiran, Kumar R Ashok, Swaroopan NM Jothi

Przegląd Elektrotechniczny

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2021

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R. 97, nr 9

130--134

EN

Renewable sources creates new opportunity when it is integrated with the microgrid increasing the energy efficiency of the system. This paper focuses on the adaptive control strategies which utilizes different energy management system for single stage PV based battery management system connected with the microgrid which operates on maximum power. The proposed system is carried in MATLAB/Simulink 2017B and its performance measures is demonstrated for different scenarios.

PL

Źródła odnawialne stwarzają nowe możliwości, gdy są zintegrowane z mikrosiecią zwiększając efektywność energetyczną systemu. Niniejszy artykuł koncentruje się na adaptacyjnych strategiach sterowania, które wykorzystują różne systemy zarządzania energią dla jednostopniowego systemu zarządzania baterią PV, połączonego z mikrosiecią, która działa z maksymalną mocą. Proponowany system jest realizowany w MATLAB/Simulink 2017B, a jego mierniki wydajności są demonstrowane dla różnych scenariuszy.

11

Maximum Power Point Tracking under simplified sliding mode control based DC-DC boost converters

Benaissa Tahar, Djillali Mahi, Khaled Halbaoui

Przegląd Elektrotechniczny

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2021

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R. 97, nr 7

60--65

EN

In this paper, a design of a simplified sliding mode controller (SMC) for Boost DC-DC converter in continuous conduction mode of operation is presented by defining a simplified formulation for sliding surface. The robustness and stability of the proposed controller are investigated to environment changes. Simulation results show that SMC provides good performance under the climatic changes in term of stability and robustness to irradiance and temperature variations. The proposed converter is a cascaded boost converters under Sliding Mode Control (SMC). The operation of the proposed control of dc–dc converter topology has been verified through simulation using Simulink and its performance has been shown to be satisfactory.

PL

W artykule przedstawiono projekt uproszczonego sterownika trybu ślizgowego (SMC) dla przekształtnika Boost DC-DC w trybie pracy ciągłej przewodzenia poprzez zdefiniowanie uproszczonego sformułowania dla powierzchni ślizgowej. Odporność i stabilność proponowanego kontrolera są badane pod kątem zmian środowiskowych. Wyniki symulacji pokazują, że SMC zapewnia dobrą wydajność przy zmianach klimatycznych pod względem stabilności i odporności na napromienienie i zmiany temperatury. Proponowany konwerter to kaskadowe przetwornice podwyższające w trybie sterowania przesuwnego (SMC). Działanie proponowanego sterowania topologią przekształtnika DC – DC zostało sprawdzone w drodze symulacji z wykorzystaniem Simulink i jego działanie okazało się zadowalające.

12

Contribution to the optimization and control of a photovoltaic system connected to the grid based a five levels inverter

Ais Belgacem

Przegląd Elektrotechniczny

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2021

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R. 97, nr 4

70--74

EN

This paper is aimed to optimizing and improving the performance of a Photovoltaic system connected to the Grid based a five levels inverter using conventional and advanced methods. The MPPT methods considered in this study include Sliding Mode Control (SMC) and Perturb and Observe (PO). We used a five level inverter controlled by passive methods to connect the PV system to the grid. The DC link voltages are controlled by using a closed loop called clamping bridge and an adaptive fuzzy logic PI controller (AFLC-PI). A PV model and power converters are modeled in Matlab SimpowerSystems toolbox and the MPPT and control algorithms are tested under different operating conditions to analyze the performance and limitations of each algorithm.

PL

Artakuł analizuje możliwoścoi poprawy właściwości i optymalizacji systemu fotowoltaicznego podłączonego do sieci I bazującego na przekształtniku piątego rzędu. Wykorzystano metodę MPPT (Maximum Power Point Tracking), sterowanie ślizgowe SMC. System is modelowany w Matlabie Simpopwer System Toolbox.

13

Sliding Mode Control of Hybrid Renewable Energy System Operating in Grid Connected and Stand-Alone Mode

Benadli Ridha, Bjaoui Marwen, Khiari Brahim, Sellami Anis

Power Electronics and Drives

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2021

|

Vol. 6 (41)

144--166

EN

This paper studies innovative application of sliding mode control (SMC) for a Hybrid Renewable Energy System (HRES) in grid-connected and autonomous modes of operation. The considered HRES includes a photovoltaic (PV), wind turbine (WT) based on a Permanent Magnet Synchronous Generator (PMSG). The PV generator is coupled to the common DC bus via a DC/DC converter. The latter is controlled by an MPPT algorithm based on the Adaptive Perturbation and Observation Algorithm Method (APOAM) to search the optimum working of this source. A SMC is utilized to manage the PV voltage to achieve the Maximum Power Point (MPP) by altering the obligation duty cycle. The battery interfaced by a bidirectional buck-boost DC/DC converter can be charged or discharged depending on the production situation. On the one hand, the wind turbine conversion chain is equipped with a PMSG and a rectifier controlled to regulate the operating point of the wind turbine to its optimum value. During a Stand-Alone Mode (SAM) operation, the Voltage Source Converter (VSC) was used for controlling the output voltage in terms of amplitude and frequency delivered to the AC load. However, in Grid-Connected Mode (GCM) operation, the VSC was adapted to control the electrical parameters of the grid. To better appreciate the advantages of the proposed SMC approach, we have proposed a series of comparative tests with the conventional PI control in the operating modes GC and SA and under different scenarios. The proposed control strategy has undeniable advantages in terms of control performance and very low total harmonic distortion THD value compared with the conventional PI control. Finally, It is concluded that the proposed approach improves the quality and provides a stable operation of the HRES.

14

Development of rapid and reliable cuckoo search algorithm for global maximum power point tracking of solar PV systems in partial shading condition

Bentata Khadidja, Mohammedi Ahmed, Benslimane Tarak

Archives of Control Sciences

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2021

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Vol. 31, No. 3

495--526

EN

The solar photovoltaic output power fluctuates according to solar irradiation, temperature, and load impedance variations. Due to the operating point fluctuations, extracting maximum power from the PV generator, already having a low power conversion ratio, becomes very complicated. To reach a maximum power operating point, a maximum power point tracking technique (MPPT) should be used. Under partial shading condition, the nonlinear PV output power curve contains multiple maximum power points with only one global maximum power point (GMPP). Consequently, identifying this global maximum power point is a difficult task and one of the biggest challenges of partially shaded PV systems. The conventional MPPT techniques can easily be trapped in a local maximum instead of detecting the global one. The artificial neural network techniques used to track the GMPP have a major drawback of using huge amount of data covering all operating points of PV system, including different uniform and non-uniform irradiance cases, different temperatures and load impedances. The biological intelligence techniques used to track GMPP, such as grey wolf algorithm and cuckoo search algorithm (CSA), have two main drawbacks; to be trapped in a local MPP if they have not been well tuned and the precision-transient tracking time complex paradox. To deal with these drawbacks, a Distributive Cuckoo Search Algorithm (DCSA) is developed, in this paper, as GMPP tracking technique. Simulation results of the system for different partial shading patterns demonstrated the high precision and rapidity, besides the good reliability of the proposed DCSA-GMPPT technique, compared to the conventional CSA-GMPPT.

15

Design and implementation of control algorithms for single-axis sun tracking systems

Kabalci Ersan, Calpbinici Ayberk

Journal of Power Technologies

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2020

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Vol. 100, nr 1

32--42

EN

Solar energy is the most widespread renewable energy source due to the modular structures of PV modules and low maintenance requirement. In this study, a sun tracking system is proposed with a view to achieving a generated energy output than with a ﬁxed PV system. There are two diﬀerent control structures and algorithms are proposed to control the sun tracking system to increase eﬃciency. The tracking system uses algorithms to determine the exact position of the sun at any time during the day and to turn the PV modules to a position perpendicular to the sun. In the ﬁrst control circuit, the position of the sun is precisely found with two identical LDRs and an angle sensor. In the second control circuit, the position of the sun is tracked by using a real time clock and an angle sensor to limit the platform. Greater energy generation is achieved by turning existing solar panels to face the sun. Furthermore, a data acquisition device stores and monitors daily irradiation data on a computer and the data entered in the database are used to produce graphic interfaces.

16

Power interface efficiency evaluation for photovoltaic system used in hydrogen production

Belgroun Zoubir, Hatti Mustapha, Hanini Salah

Przegląd Elektrotechniczny

|

2019

|

R. 95, nr 6

81--85

EN

In this work, we will compare between two types of converters Cuk and SEPIC because they are the most widely used and are two of the developed family of the converter. This paper presents under MATLAB/Simulink the use of CUK converter with maximum power point tracking (MPPT) technology, to increase its efficiency by an algorithm Perturb and Observe (P&O) and incremental conductance method, then we will apply artificial neural network (ANN) to avoid the disadvantages of MPPT Classical. The MPPT developed presents a better behavior than the P&O system.

PL

W artykule porównano dwa rodzaje przekształtników CUK i SEPIC ponieważ są one najczęściej używane. Przedstawiono symulację użycia przekształtnika CUK w technice śledzenia punktu maksymalnej mocy MPPT oraz algorytmy Perturb and Observe (P&O) przyroostowej przewodności.

17

Metoda śledzenia punktu mocy maksymalnej do sterowania turbiną wiatrową o regulowanej prędkości obrotowej

Baran Janusz, Jąderko Andrzej

Przegląd Elektrotechniczny

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2019

|

R. 95, nr 12

89--92

PL

W artykule zaprezentowano metodę sterowania turbiną wiatrową o zmiennej prędkości, opartą na śledzeniu punktu mocy maksymalnej (MPPT). Metoda nie wymaga znajomości charakterystyki Cp(λ) turbiny. Algorytm znajduje moc maksymalną turbiny poprzez zmianę prędkości kątowej wirnika turbiny i obserwację rezultatu w postaci przyrostu bądź zmniejszenia mocy wyjściowej. Operacja powtarza się iteracyjnie w kierunku wzrostu mocy, aż do osiągnięcia punktu mocy maksymalnej na krzywej Pt (ω), gdzie dPt/dω = 0. Wartość prędkości zadanej obliczana przez algorytm jest użyta do wyliczenia wartości zadanej momentu generatora. Głównym problemem zastosowanej metody są zmiany położenia krzywej Pt(ω) i punktu mocy maksymalnej wraz ze zmianą prędkości wiatru, co może powodować błędne określenie aktualnego punktu pracy przez algorytm sterowania. W celu zweryfikowania zaproponowanego algorytmu przeprowadzono badania symulacyjne w środowisku MATLAB-Simulink. Wykorzystano rzeczywiste parametry turbiny wiatrowej o mocy 40 kW.

EN

The paper presents a hill climbing method of maximum power point tracking control for a variable-speed wind turbine energy conversion system. The method does not require knowledge on the turbine parameters, power coefficient characteristics Cp(λ) nor air speed and density. The algorithm searches for the generator peak power by varying the angular speed and observing if it results in increment or decrement of the output power. The operation is repeated iteratively in the direction of the power growth until the peak power point dP/d =0 on the P curve is reached. The speed reference calculated by the algorithm is used to modify the generator reference torque. The main difficulty is that P curve and the peak power point vary with the wind speed so the algorithm may wrongly recognize current position on the power curve. Illustrative Matlab/Simulink simulations carried out for a 40 kW fixed pitch wind turbine data are presented to verify the presented algorithm.

18

Induction generator with three-level inverters and LCL filter connected to the power grid

Kasprowicz A.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2019

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Vol. 67, nr 3

593--604

EN

The paper presents an induction generator connected to the power grid using the AC/DC/AC converter and LCL coupling filter. In the converter, both from the generator and the power grid side, three-level inverters were used. The algorithm realizing pulse width modulation (PWM) in inverters has been simplified to the maximum. Control of the induction generator was based on the indirect field oriented control (IFOC) method. At the same time, voltage control has been used for this solution. The MPPT algorithm has been extended to the variable pitch range of the wind turbine blades. The active voltage balancing circuit has been used in the inverter DC voltage circuit. Synchronization of control from the power grid side is ensured by the use of a?PLL loop with the system of preliminary suppression of undesired harmonics (CDSC).

19

A performance analysis of a hybrid golden section search methodology and a nature-inspired algorithm for MPPT in a solar PV system

Mostafa Hazem H., Ibrahim Amr M., Anis Wagdi R.

Archives of Electrical Engineering

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2019

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Vol. 68, nr 3

611--627

EN

This research presents a comparative study for maximum power point tracking (MPPT) methodologies for a photovoltaic (PV) system. A novel hybrid algorithm golden section search assisted perturb and observe (GSS-PO) is proposed to solve the problems of the conventional PO (CPO). The aim of this new methodology is to boost the efficiency of the CPO. The new algorithm has a very low convergence time and a very high efficiency. GSS-PO is compared with the intelligent nature-inspired multi-verse optimization (MVO) algorithm by a simulation validation. The simulation study reveals that the novel GSS- PO outperforms MVO under uniform irradiance conditions and under a sudden change in irradiance.

20

An Optimal Power Point Tracking Algorithm in a Solar PV Generation System

Hussan Reyaz, Kumari Manita, Sarwar Adil, Iqbal Atif, Tariq Mohd, Guziński Jarosław

Acta Energetica

|

2019

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nr 4

21--32

EN

The non-linearity in I-V characteristics of a PV panel requires to be operated at knee point to extract maximum power. In order to operate the panel at optimal point, maximum power point tracking (MPPT) algorithm is employed in the control structure. The main objective of MPP tracking is to keep the operation at knee point of I-V characteristics under varying condition of temperature and solar insolation. Under non uniform solar PV insolation falling on PV panels connected in series, a partial shading condition (PSC) occurs under cloud or shadow effects causes multiple power peak formation. The conventional MPPT methods fail to converge at global maximum power point (GMPP) under the PSC condition. Occurrence of these multiple peaks on characteristics of P-V makes tracking very difficult and requires integration of an efficient algorithm that differentiates between global and local maximum power point. This paper proposes a variable structure constant voltage method to overcome the problem faced by conventional MPPT methods. Moreover, quadratic boost converter has been taken for MPPT operation for increasing the effective gain of the converter. The effective operation of control algorithm has been validated in simulation results.

PL

Na skutek nieliniowości charakterystyk I-U panelu fotowoltaicznego jego maksymalną moc uzyskuje się, gdy pracuje on w punkcie przegięcia. Aby panel pracował w optymalnym punkcie, w strukturze sterowania należy zastosować algorytm śledzenia punktu mocy maksymalnej (ang. maximum power point tracking – MPPT). Głównym celem śledzenia MPP jest utrzymanie działania panelu PV w punkcie przegięcia charakterystyki I(U) (w tzw. kolanie) niezależnie od zmian temperatury i nasłonecznienia. Pod wpływem częściowego zacienienia paneli fotowoltaicznych połączonych szeregowo (ang. partial shading conditio – PSC), np. z powodu zachmurzenia, na charakterystyce I(U) powstaje kilka punktów przegięcia. Konwencjonalne metody MPPT nie prowadzą do zbież- ności w globalnym punkcie mocy maksymalnej (ang. global maximum power point – GMPP) w warunkach PSC. Występowanie kilku szczytów na charakterystyce P(U) bardzo utrudnia śledzenie optymalnego punktu pracy i wymaga użycia takiego algorytmu sterowania, który rozróżnia globalne i lokalne punkty mocy maksymalnej. W celu rozwiązania tego zagadnienia zaproponowano w artykule układ regulacji o stałym napięciu i zmiennej strukturze sterowania. Aby zwiększyć wzmocnienie napięciowe układu energoelektronicznego, zastosowano podwójny przekształtnik podwyższający napięcie. Skuteczne działanie algorytmu sterowania zostało potwierdzone wynikami symulacji.