Efficiency Of Photovoltaic Array Research Articles

Greenhouse gas emissions reduction and energy savings for a dredger at port area using hybrid photovoltaic power system onboard

For reducing greenhouse gas (GHG) emission and saving energy, a hybrid photovoltaic (PV) energy system comprised of grid-connect and off-grid modes was utilized on a dredger at emission control area (ECA) such as a port area. The experiments on this hybrid PV power system were carried out to evaluate the electric energy consumption of each equipment onboard in three operation modes (dredging, rest and idle) of dredger and to analyze the contribution of such a PV power system. The PV array had charging batteries in grid-connect mode and converted the PV power to alternating current (AC) directly during daytime period. At nighttime, the batteries could supply the electric power in off-grid mode. Even this dredger is no large free deck area for installing PV arrays onboard, the power conversion for PV array can offer about 1.0 % of total demand electric energy yearly. After evaluating the electric power consumption of each equipment onboard at different dredger operation mode, the proposed hybrid PV power system can offer 4.0 % (3.9 kWh by 96.8 kWh) of energy demand in grid-connect at rest mode and supply 100 % (29.85 kWh by 29.85 kWh) energy for dredger equipment in off-grid without diesel generator running at idle mode. This hybrid PV power system on the dredger has not only saved marine diesel oil (MDO) 2094.2 kg/year, reduced GHG of CO2 about 6455 kg/year, SOx about 3.942 kg/year and particulate matter (PM) around 1.97 kg/year but also reduced the diesel generator maintenance cost from stop running for 15 h/day and saved the cost of fuel (MDO) about USD 2128.5/year. The hybrid PV power system exhibited very effective efficiency of PV array and optimized the installation of batteries bank in ship with limited deck space at ECA and port area with high solar radiation density zone.

Hybrid Water Pumping Control System for Irrigation using Arduino

Abstract: There are many water pumping system such as diesel powered, solar photovoltaic, mechanical windmill exists. Few combine solar and wind energy sources to provide better performance and reliability to the existing system. In this paper wind turbine and solar photovoltaic (PV) water pumping array are analyzed separately and are combined as a hybrid system. Large amount of water pumped from the water resources are not effectively used. So a suitable control methodology was also proposed to operate the pump automatically depending on the water availability and the water requirement for crops .The main objective is to provide 1.Advantage of hybrid system over WT or solar PV array separately.2.suitable methodology to prevent water loss. Additionally MPPT system Can be used to improve the efficiency of PV array

High-performance global peak tracking technique for PV arrays subject to rapidly changing PSC

In the P--V characteristics of photovoltaic (PV) arrays that are subject to rapidly changing partial shading conditions (PSC), there usually exist several peaks. High-performance global peak tracking plays a quite significant role in improving the energy efficiency and energy extraction of PV arrays. Many global peak tracking techniques (GPTTs) have been proposed to find the global maximum power point (GMPP) for photovoltaic arrays. Although existing techniques have their advantages in tracking the GP, they cannot work well under rapidly changing partial shading conditions. Moreover, when valleys around a local peak (LP) are relatively deep and narrow, these techniques cannot avoid being trapped in the LP. In order to deal with the rapidly changing partial shading conditions, as well as improving the accuracy of GPT, a novel and extremely fast Quantum annealing (QA)-based global peak tracking technique (QAGPTT), is designed for PV arrays in this paper. Compared to the conventional techniques, quantum annealing utilizes quantum effects to tunnel through potential barriers instead of relying on the inefficient and time-consuming thermal fluctuations or perturbation to climb potential barriers surrounding a local minimum. Theoretical analyses and extensive experiments show that our technique is more suitable for global peak tracking under rapidly changing partial shading conditions, especially when valleys around a local peak are relatively deep and narrow.

A novel strategy for implementation of intelligent techniques in solar photovoltaic arrays to improve the performance and various comparison of partial shading mitigating techniques

ABSTRACT This paper proposes a new reconfigure technique to improve efficiency by reconfiguring the photovoltaic array during the different partial shading conditions and comparative analysis with various partial shading mitigating techniques. Normally, the photovoltaic array efficiency is less even if the shading occurs in parts on the PV panels in an array. To extract maximum output from solar PV panels, the different modulation and MPPT techniques are utilized. Due to continuous and discontinuous partial shading, this MPPT technique also fails to perform a uniform power voltage curve. Therefore, to improve the efficiency and performance of the PV array, a prudent solution is needed to dispersing the shading by reconfiguring the solar panel array. Most of the present reconfiguration schemes are quite complex, succumb to erroneous execution, and not suitable for practical implementations. The proposed Intelligent Reconfiguration Technique (IRT) technique is well suited for extension of power ranges and it offers smooth power vs voltage graph there by the algorithm struck up in local maxima can be averted. Also the superiority of the IRT method quantitatively proven in Table 6 by comparing other methods with various shading patterns.

Long term operational performance and experimental on-field degradation measurement of 10 MW PV plant in remote location in India

The paper presents extensive monitoring, detailed long term operational performance and on-field degradation measurement of utility scale grid connected 10 MW solar photovoltaic (PV) plant in real operating conditions. Different performance indices are evaluated incorporating IEC standard 61724 guidelines based on actual plant monitoring data (incident solar irradiation, ambient and module temperature and generated electrical energy) from January 2016 to December 2020 (period of five years). The annual average reference, array and final yield, performance ratio, capacity utilization factor, array capture and system losses, PV array and system efficiency of the plant were found to be 6–6.7 h/day, 4.83–5.1 h/day, 4.69–4.86 h/day, 72–74%, 19–20%, 1.02–1.33 h/day, 0.15–0.156 h/day, 12% and 11% respectively. Degradation of fielded modules is assessed by visual inspection and I-V curve tracing. Correlation of I-V characterization with electrical parameters of visually degraded installed PV modules is also presented. The calculated linear degradation rates varied from 0.97 to 1.52%/year in modules with considerable bird dropping, 1.33 to 1.61%/year in modules with light EVA discoloration, 1.6 to 1.86%/year in modules with glass breakage, 2.31 to 3.94%/year in modules with glass breakage and dark EVA discoloration, and 2.97 to 5.8%/year in modules with glass breakage and cell cracks. The annual linear degradation rates were found to be in the range of 0.9 to 1.1%/year for normal fielded modules with no visible degradation and 0.97 to 2.9%/year for visually degraded modules with mean and median values of 1.8%/year and 1.6%/year with six years operational period. The levelized cost of electricity, simple and discounted payback period and return on investment were found to be 4.05 Rs, 5.5 years, 11 years and 62.22% respectively. Annual CO2 savings of the plant is around 16,000 tons and CO2 emission reduction potential of installed pc-Si technology is found to be 1.6 tons/kWp.

Implementation of adjustable variable step based backstepping control for the PV power plant

The most recent research challenge in sustainable photovoltaic (PV) energy is to maintain a high efficiency of PV arrays. Our contribution in this issue is reducing the power loss caused by environmental condition change and parametric variations. A non linear recursive Backstepping maximum power point tracking (MPPT) controller based on an adjusted variable step Perturb and Observe (P&O) algorithm (VS-Backstepping) is proposed to gather the maximum power with fast converge time from the PV system. The trade off between the high accuracy and the fast tracking speed cannot be realized through single MPPT techniques. Thus this work combines two individual MPPT controllers. However, the accuracy for finding the maximum power is highly related to the part of MPP tracking control using the Backstepping approach as well as the rapidity to reach the MPP is managed with the adjusted variable step P&O algorithm. To further evaluate the effectiveness of the proposed method (VS-Backstepping), simulation and experimental results on a commercial PV panel are presented and compared to an individual fixed step P&O algorithm and a variable step P&O (VS-P&O) controller.

Fault diagnosis approach for photovoltaic array based on the stacked auto-encoder and clustering with I-V curves

Photovoltaic arrays are usually installed outdoors in harsh environments and prone to various faults, which will seriously affect the efficiency of photovoltaic arrays. Therefore, the effective fault detection and diagnosis plays an important role in the safe, operation, and maintenance of the photovoltaic plant. In recent years, machine learning methods have made remarkable achievements in fault diagnosis. However, there still exist some limitations: (1) feature extraction relies on expert experience and lacks automation. (2) artificial feature extraction easily ignores some potential useful features. (3) the nonlinear characteristics of current–voltage curves cannot be effectively learned by the shallow network structure. In order to address the above issues, the supervised deep learning methods with automatic feature extraction capability are applied, but a lot of labeled data are required for pre-training. Therefore,a fault diagnosis method is proposed for photovoltaic array based on stacked auto-encoder and clustering algorithm in this paper, which can automatically extract features and use a small number of labeled data samples to mine data sample features for fault diagnosis. Firstly, the effective features are automatically extracted by the stacked auto-encoder from the current–voltage curves. Secondly, the dimension of the features is reduced and visualized by the t-distributed stochastic neighbor embedding to improve the performance of the clustering algorithm. Finally, clustering centers and clusters are obtained by clustering algorithm and membership function is used for fault diagnosis. Moreover, the simulation and experimental data are used to verify the performance of the proposed fault diagnosis method. The 97.3% and 98.3% classification accuracies are obtained in the simulation and experimental results.

MPPT control based on improved mayfly optimization algorithm under complex shading conditions

Abstract The output power curve of the photovoltaic array presents a multi-peak characteristic under partial shading conditions, which causes the traditional maximum power point tracking technology to fail to guarantee the maximum power output of the photovoltaic cell. In response to this problem, this paper proposes to apply the improved Mayfly Optimization Algorithm (MA) to the maximum power tracking control. By introducing the gravity factor and limiting the search space of male mayfly, the optimization accuracy of the algorithm is enhanced, the vibration of the algorithm near the MPP is reduced, and the occurrence of premature phenomenon is avoided. Three test functions are selected to verify the algorithm, and under the conditions of rapid irradiance changes and complex shadow occlusion, an MPPT model based on the Boost circuit is established to verify the effectiveness of the algorithm. The simulation results show that the improved MA algorithm can effectively converge to MPP under complex shading conditions, and the output efficiency of photovoltaic arrays can be maintained above 99.96%. The average tracking time for different shading patterns is about 0.15 s.

A Novel Magic Square Based Physical Reconfiguration for Power Enhancement in Larger Size Photovoltaic Array

Partial shading is the prevailing problem in Photovoltaic arrays. It results in severe consequences like multiple peaks in electrical characteristics, hot spots on Photovoltaic panels, disruptions in tracking maximum power and reduced output power. During most of the shading conditions, the shade concentrates in a particular area of the Photovoltaic (PV) array. This shading reduces PV array efficiency. Several physical reconfiguration schemes based on puzzle patterns are proposed to minimize this problem. The majority of these methods deduced to fixed PV array size for which the algorithm has proposed. Further, few of them are applicable only to lower size PV array. This paper presents a novel magic square puzzle for scattering the shade in the PV array to overcome the above constraints. In this method, the module physical position remains the same. However, the electrical wiring alters according to the puzzle pattern to change the row current in the Total-Cross-Tied topology PV array. The efficiency of the proposed system is examined under different shading conditions using characteristic curves. The relative analysis was carried between the conventional Total-Cross-Tied topology and the proposed Novel Magic Square-based Total-Cross-Tied topology. The MATLAB/SIMULATION results demonstrate that placing the modules according to the proposed reconfiguration method minimizes the peaks and enhances the output power (11.53%), with the global peak always on the right side of the PV curve under partial shading conditions.

Firefly Algorithm-Based Photovoltaic Array Reconfiguration for Maximum Power Extraction during Mismatch Conditions

This studyaimed at improving the performance and efficiency of conventional static photovoltaic (PV) systems by introducing a metaheuristic algorithm-based approach that involves reconfiguring electrical wiring using switches under different shading profiles. Themetaheuristicalgorithmused wasthe firefly algorithm (FA), which controls the switching patterns under non-homogenous shading profiles and tracks the highest global peak of power produced by the numerous switching patterns. This study aimed to solve the current problems faced by static PV systems, such as unequal dispersion of shading affecting solar panels, multiple peaks, and hot spot phenomena, which can contribute to significant power loss and efficiency reduction. The experimental setup focusedon software development and the system or model developed in the MATLAB Simulink platform. Athorough and comprehensive analysis was done by comparing the proposed method’s overall performance and power generation with thenovel static PVseries–parallel (SP) topology and totalcross-tied (TCT) scheme. The SP configuration is widely used in the PV industry. However, the TCT configuration has superior performance and energy yield generation compared to other static PV configurations, such as the bridge-linked (BL) and honey comb (HC) configurations. The results presented in this paper provide valuable information about the proposed method’s features with regard toenhancing the overall performance and efficiency of PV arrays.

Performance evaluation of a decentralized rooftop solar photovoltaic system with a heat recovery cooling unit.

The present work represents a detailed performance analysis of a 5-kWp on-grid solar photovoltaic rooftop system installed on a flat roof of a hospital building at a height of 12 m from the ground level, located at Perambalur (latitude 11° 23' N and longitude 78° 93' E), Tamilnadu, India. The daily, monthly and annual average performance parameters of the PV system including energy output, final yield, reference yield, array yield, photovoltaic array efficiency, system efficiency, inverter efficiency, performance ratio and capacity utilization factor have been analysed. The environmental benefit analysis and the payback period of the installed solar photovoltaic plant are also discussed. This solar photovoltaic power plant generates around 7144 kWh per annum of electrical energy, which is fed into the grid, and the annual average array, inverter, system efficiency, capacity utilization factor and performance ratio of the plant are found to be 12.15%, 97.12%, 11.72%, 16.31% and 76.83%, respectively, during the year 2019. The overall PV module electrical efficiency has been increased by 1.21% by applying the forced air circulation mechanism and 2.31% by applying the forced water circulation mechanism. Subsequently, the heat gained by the system can be utilized for heat load application. The installed solar photovoltaic power plant has a positive impact on greenhouse gas emissions with a reduction of 11.287 t of CO2, 8.86 kg of SO2, 18.50 kg of NOx and 485.792 kg of ash per annum. The water-based cooling in photovoltaics can potentially generate an output energy of 7310 kWh, which is relatively higher than the energy generated by the photovoltaic module with air cooling.

Reconfiguration Method in Photovoltaic Array for Nonuniform Shading Condition

The output of the photovoltaic array is directly related to the external environment and solar irradiation. Photovoltaic arrays are affected by partial shading which deviates the VI and PV curve from ideal state. This phenomenon influences the operating efficiency of Photovoltaic arrays, as generated power is reduced and hotspots are formed. One possible way to get rid of such negative phenomenon is to reconfigure the Photo voltaic arrays and another method is to operate Photo voltaic panels in peak voltage, which includes global maximum power (GMP) but it has few drawbacks like high complexity, time-consuming. This paper proposes a new methodology of reconfiguring series-parallel (SP) photovoltaic array, which is implemented on MATLAB Simulink. The scheme extracts maximum power by electrically connecting all the shaded or underperforming photovoltaic panels in a common series connection, such that the restricted flow of electricity due to shaded panels is only restricted through one part of the series-parallel photovoltaic array. This method is unlike some interconnection method as it utilizes a reconfigurable part to normalize the fixed part, it is completely adaptable. The obtained results from simulation prove the reliability and overall efficiency under partially shaded array configuration.

A Novel Hybrid Approach for Maximizing the Extracted Photovoltaic Power under Complex Partial Shading Conditions

The convenient design of a maximum power point tracking (MPPT) controller is key to the success of photovoltaic (PV) system performance in order to maximize the extracted power, which is affected significantly by weather fluctuations, particularly partial shading condition (PSC). This paper proposes a novel hybrid MPPT approach based on a modified Perturb and Observe (P&O) assisted by the Extremum Seeking Control (ESC) strategy, combining the benefits of these simple algorithms and, meanwhile, eliminating their drawbacks. The proposed algorithm is able to track the maximum possible power under any level of weather fluctuation, with comprehensive enhancement on all aspects of high performance, boosting the PV array efficiency to 100%, reducing the convergence time to less than 100 ms, completely eradicating the oscillations around the achieved power, and maintaining the simplicity levels of both involved strategies. More importantly, this algorithm is applicable for any PV array configuration, which enhances the robustness and novelty of the algorithm. The performance is verified using MATLAB/Simulink. A boost converter is used for controlling DC to DC (direct current to direct current) power. The proposed algorithm’s performance is compared with the conventional P&O and incremental conductance (IC) algorithms under four different cases of weather conditions. The shortcomings of these algorithms are illustrated and the analysis confirms the effectiveness of the proposed algorithm accordingly.

Многофакторный анализ эффективности фотовольтаического массива.

Многофакторный анализ эффективности фотовольтаического массива.

Design and Implementation of Real-Time Monitoring System for Solar Power Plant in Surabaya, Indonesia

Availability of renewable energy now makes solar energy the right choice because of its advantages and easy application compared to other renewable energy sources. Monitoring of the output parameters of solar power plants needs to be done to assess the performance and efficiency of a solar power plant in real environmental conditions. The aims of research is to provide a direct and real time monitoring. This research has been carried out in solar power plants at Engineering Physics Department, FTI-ITS. The design of an ATmega32 microcontroller-based system that is integrated with Raspberry-pi as a data acquisition system. Data reading solar power plants output parameters stored in memory can be downloaded at any time. The analysis result shows that the efficiency of photovoltaic arrays is 10.78 %. The total efficiency of the solar power plants system is 8.05 %.

Determination of the best shading pattern to maximize the power of TCT connected solar PV array during partial shading condition

In solar photovoltaic (PV) array, sometime it is seen that some parts of the array gets shaded due to the obstacles like trees, nearby houses, and pillars. This phenomenon is commonly known as partial shading. During partial shading, the efficiency of the solar PV array decreases severely. Because of that, the maximum power point (MPP) of the whole PV array decreases heavily. If the partial shading occurs in the same location for a longer period of time due to the deposition of dust or mud or obstacles, it causes overheating at that portion of PV module. As a result, the module gets damaged due to the generation of hot spot. In this paper, an effort is made to explain the behavior of the solar PV array in different shading patterns. Along with that, a detail comparison regarding the best possible pattern of shading is discussed to increase the efficiency of the PV array during partial shading condition. For different shading patterns and different environmental conditions, the voltage–current (V–I) and the voltage–power (V–P) characteristics are shown for both simulation and experimental setup. Finally, the MPP is calculated for both the cases and is found that they exhibit similar results.

Maximum Power Point Tracking Algorithm for Grid-connected Photo Voltaic System

The Photo-Voltaic (PV) system is designed to supply solar power through photo-voltaic. The PV generator exhibits non-linear voltage-current characteristics and its Maximum Power Point (MPP) varies with cell temperature and solar radiation. The MPP Tracking (MPPT) technique gains more attraction in the field of PV systems and it is considered as a vital part in photovoltaic system design to maximize the output power of a photovoltaic array. The conversion efficiency of PV arrays is typically low; it requires MPPT control techniques to enhance the efficiency. The MPPT technique has been proposed for PV systems to reach the MPP. The most common issues associated with MPPTs are low tracking efficiency, need more transient time and steady state oscillation. This paper presents a comprehensive review of the MPPT techniques and analyzed the merits and demerits with different factors such as MPP, tracking error and power estimation error.

Experimental Study of a Photovoltaic Direct Current Water Pumping System for Irrigation in Rural-Isolated Region of Arequipa, Peru

In the present experimental study, a photovoltaic (PV)-powered system in continuous current (4 kW) for the pumping of water in an isolated, rural agricultural zone in Arequipa—Peru was analyzed. A meteorological station was installed in the studied zone, measuring solar radiation, temperature, relative humidity, and wind speed. The electrical and hydraulic parameters of the solar-pumping system (i.e., electric current, voltage, mass flow, and hydraulic pressure) were measured in order to evaluate the efficiency of the energy transformation processes. The results indicate that, during the year of 2017, the PV pumping system in direct current (DC) functions from 07 h 30 min to 15 h 30 min, during an average of 8 h a day. The PV array, hydraulic, and global efficiencies were evaluated. This allows for the interpretation of efficiency independent of solar irradiance. The efficiency of the PV array and global efficiency remained constant (11.5% f and 8.5%, respectively). The functioning interval of the PV array ranges from 880 W up to 3400 W, making evident the versatility of the system of generation and consumption in DC, which is able to function since solar irradiance is at least 200 W/m2, corresponding to 880 W of PV array power, 27 m of total dynamic head (TDH) and 2 kg/s of mass flow, and 70% hydraulic efficiency. With greater mass flows (6.3 kg/s), the PV array power was 3256 W with a hydraulic efficiency of 55%, a TDH of 30 m, and a peak solar irradiance of 1190 W/m2. When the whole system functions in DC, the efficiencies are superior to those of systems, which operate with DC/alternating current (AC) current inverters.

English

A solar photovoltaic (PV) water pumping system was investigated to determine performance and economic viability. An in-built data logger was used to collect real time data on key performance parameters. Performance indicators were defined and determined, while economic viability was analyzed using life-cycle cost (LCC) method and these costs were compared with a diesel generator pumping system. Solar irradiance varied from 63 W/m2 to a peak of 857 W/m2, corresponding to a maximum power output of 11.75 kW. PV array efficiency of 12.1%, sub-system efficiency of 91.82% and overall efficiency of 5.14% were obtained, which are well comparable to the efficiencies reported elsewhere for similar systems. The LCC analysis showed a 20 year average unit water cost of 0.25 US $/m3 for solar PV system and 0.6 US $/m3 for diesel genset system. Solar PV system is found to be more cost effective and suitable for use over conventional sources. Key words: Photovoltaics, water pumping, life-cycle cost analysis, efficiency, unit water costs, diesel generator.

Evaluation of some effective parameters on the energy efficiency of on-board photovoltaic array on an unmanned surface vehicle

ABSTRACTProviding energy for an unmanned robot boat, which should work autonomously for hours on water, requires some special attentions. To increase generated energy, some excellent options are evaluated in on-board photovoltaic system of an unmanned robot boat. The research is initiated by simulating the energy generation system of the unmanned surface vehicle (USV), then study of some effective parameters on the efficiency of photovoltaic array on the USV. Temperature, sun tracking and glass transparence are three factors that are evaluated by simulation and experimental tests to obtain their effects on the PV efficiency. Temperature analysis illustrated that generated energy can increase to 12.9%, by controlling thermal effect. Furthermore, one-axial sun tracking system would increase the amount of energy up to 20% in some cases. Cleaning panels is another effective parameter that can raise daily average of harvested energy by 15.7%. Finally, it is concluded that total PV efficiency on the USV can improve up to 50% by accurate tracking and well maintenance.