Output Power Of Photovoltaic Array Research Articles

Tie failure detection technique for total cross tied solar photovoltaic system

Partial Shading in the solar photovoltaic (PV) system leads to more power loss due to mismatch among cells or module’s power generation. The Total Cross Tied (TCT) array design approach is employed for Partial Shading Conditions (PSC) to reduce this issue and boost output power. A tie is used to connect the strings and modules in a solar-powered photovoltaicarray. However, external environmental conditions like strong winds and storms may influence this tie to break. The conventional protection and fault identification technique in the PV system failed to detect this fault. The Solar PV system's entire power generation is drastically impacted by this TCT tie connector problem. Furthermore, during PSC, there is a notable fall in power generation too. To address this, a new technique has been proposed in this work which is capable of precisely identifying the tie interconnection fault in the PV array. A line inspector circuit is used to identify and classify the partial shading and tie interconnection fault. This proposed technique is experimentally verified in the 4 × 4 PV array of 160 W. In all the cases, the proposed algorithm exactly finds the tie interconnection failure. When the diagnosed fault is fixed, the PV array's power output is found to rise by up to 4.5 times.

Supply and demand balance control strategy for microgrids considering uncertainty and disturbance based on online H∞ policy iteration

Abstract With the rapid growth of renewable energy generation, its proportion in power generation is increasing. Accompanied by this, due to the uncertain characteristics of renewable energy generation, the issue of imbalanced power supply and demand in microgrids has posed, which brings great challenges to the reliability of microgrid. In recent years, how to use energy storage system to solve this problem has become a hot research topic in microgrid. In this paper, an online H∞ policy iteration algorithm is proposed to control the output power of photovoltaic arrays and micro-gas turbines. At the same time, considering the uncertainty of the load demand in the microgrid system and the input disturbance of the micro gas turbine governor, the power supply and demand relationship of the microgrid can be balanced by the proposed control strategy. Finally, the effectiveness and practicality of the control strategy were demonstrated through simulation analysis.

A Novel Reverse Combination Configuration to Reduce Mismatch Loss for Stratospheric Airship Photovoltaic Arrays

Enhancing the output power of stratospheric airship photovoltaic arrays during months with weak irradiance is crucial for extending the endurance of airships. Models for predicting the output power of photovoltaic arrays and the phenomenon of mismatch losses have been proposed. However, static reconstruction schemes to reduce or eliminate mismatch losses have not been studied. In this paper, an output power model for stratospheric airship arrays including the solar radiation and irradiance distribution is established. The characteristics of the irradiance distribution for the photovoltaic array (PV) are investigated through simulation. Furthermore, an innovative reverse combination configuration is developed and compared to the SP and TCT configurations in terms of performance, mismatch loss and fill factor. Finally, simulations are conducted for a full-day irradiance period of 4 days in a real wind field. The simulation results demonstrate that the proposed RC configuration significantly reduces mismatch losses and output power fluctuations, thereby enhancing the PV array’s output power. This research provides interesting insights for the design of PV array topologies for stratospheric airships.

PV Array Reconfiguration for Global Maximum Power Optimizing Under Partial Shading Conditions Based on PV Switched System

Background: Due to the partial shading effects on different photovoltaic (PV) modules in a PV array, PV module operating conditions are inconsistent, and PV array output power is significantly reduced. Although the maximum power point (MPP) of a non-uniform irradiance PV array can be observed through global maximum power point tracking (GMPPT), no evaluation of the array's energy potential has been done. Objective: One of the most effective solutions to overcome the negative effects of partial shading in PV systems is the PV array reconfiguration process. To optimize the electrical structure of the PV array as the PV modules are partially shaded in a non-uniform manner, this study proposes a promising technique for dynamic reconfiguring a PV array in order to improve the extracted maximum power from a PV array under partial shading conditions (PSC). Method: PV modules are rearranged by iteratively sorting them to allow the PV array with nonuniform irradiance to produce as much power as possible. This is conducted by applying a switching matrix to implement a PV-switched system approach. The proposed system with different PV array dimensions (e.g., 3×4, 4×6, and 5×8) is assessed in order to validate the proposed algorithm. A MATLAB/Simulink PV array developed model is used to find the global maximum power point for the different PV array dimensions in both pre-reconfiguration and post-reconfiguration states. Results: A detailed numerical comparison of the extracted power from the proposed system has been provided. Conclusion: The results show that the proposed system has the potential to extract the exact global maximum power for a PV-switched system under PSC, irrespective of array dimensions, according to simulation results.

Cross kit reconfiguration algorithm for enhanced output power of PV array during shading mismatch conditions

Maintaining the uniform irradiance in an extensive photovoltaic (PV) system is almost impossible. The mismatch between panels of a PV array results in substantial power loss. The PV panels in an array are reconfigured by the proposed Cross-Kit (CK) technique to obtain optimal power output for different partial shade situations (PSS). The suggested approach allows the structure to balance the shade effect across the entire PV array with different physical places of panels. The PV modules are linked using the Total Cross Tied (TCT) configuration, and the CK technique decides the physical placement of modules within the array. The electrical connections of the TCT-linked PV array are unaffected by the CK panel configurations. The PV array’s output arranged with the suggested CK method is assessed and contrasted with TCT and Odd-Even (OE) reconfiguration for mathematical and experimental validation. Four different PSS are taken into consideration. The percentage instantaneous maximum power improvement compared to TCT and OE ranges from 5.49% to 26.73%. The benefits of the suggested approach include straightforward guidelines for implementation, explanation of the P-V plots, and a reduced charge of maximum power point tracking.

Improved-Odd-Even-Prime Reconfiguration to Enhance the Output Power of Rectangular Photovoltaic Array under Partial Shading Conditions

The output power of a PV (photovoltaic) array decreases due to the partial shading condition (PSC). If one or more PV modules receives less irradiance compared to other PV modules in a PV array then it is called PSC. To enhance the output power of PV array under PSC, Sudoku, and Optimal Sudoku Reconfiguration techniques are available in the literature for perfect squared PV arrays, such as 4 × 4, 9 × 9, and 16 × 16. Odd–Even and Odd–Even–Prime reconfigurations are available for rectangular PV arrays. To enhance the output power of rectangular PV array further, this paper proposed a new reconfiguration technique called Improved Odd–Even–Prime reconfiguration. To validate the proposed method, two PV arrays 9 × 9 and 8 × 9 have been implemented.

Innovative high-speed method for detecting hotspots in high-density solar panels by machine vision

Abstract The occurrence of hotspots in photovoltaic panels is one of the most common problems of solar power plants, which reduces the output power of photovoltaic arrays and can also cause irreparable damage to the solar cells. There are several ways to identify hotspots, including using custom datasets using thermographic camera images, which will be later used to teach YOLO and Faster R-CNN computer vision algorithms. In practice, it is observed that the YOLO algorithm is many times faster than the Faster R-CNN in high-density solar panels. Therefore, the applied method is the safest choice for automatic hotspot detection in large-scale photovoltaic power plants to improve overall efficiency. In this paper, by comparing the performance of methods such as Faster R-CNN with YOLO, we concluded that the YOLO algorithm has far better advantages in terms of quality of detection, and speed. Therefore, this factor makes the use of YOLO significantly helps to speed up the troubleshooting of solar modules caused by hotspots, and this factor improves the efficiency of solar power plants in the long run. Meanwhile, in the studies for this paper, the results extracted by Python have been optimized as an algorithm to be used for hotspot detection.

Effect of Partial Shading on the Performance of Various 4×4 PV Array Configurations

Electrical energy usage has drastically increased in recent decades, resulting in significant demand for renewable energy sources, especially solar. With the development of technology, extracting energy from photovoltaic (PV) modules has become easier and more economical. The performance of PV array decreases under an intermittent environment such as partial shading conditions (PSCs), causing fluctuations in PV array power output. This paper presents the analysis of a 4×4 PV array configuration under different PSCs. The power output of PV array depends on factors such as the type of configuration, size of array, and shading patterns. The performance of various types of 4×4 PV array configurations under different shading situations are compared and analyzed in this study, and the results presented.

Improved Performance of PV Water Pumping System Using Dynamic Reconfiguration Algorithm Under Partial Shading Conditions

Partial shading (PS) conditions severely degrade the solar photo-voltaic water pumping system (SPWPS) efficiency. Due to partial shading, the output power of the photovoltaic (PV) array reduces, which minimizes the pumping output. Therefore, this paper designs a smart SPWPS for total cross tied (TCT) PV array. The design of smart SPWPS consists of irradiance, voltage, and current sensors. The irradiance sensor measures the real-time irradiation data of each module in the TCT connection. Based on real-time irradiation data, this paper proposes a dynamic reconfiguration algorithm with the help of switches that increases the PV array output power compared to normal TCT connection under partial shading conditions. The enhanced output power increases the water discharge of SPWPS. The voltage and current sensors are utilized for maximum power point tracking (MPPT) operation. Voltage by frequency (V/f) control with sinusoidal pulse width modulation helps to operate the induction motor smoothly. Further, simulation and experimental studies have been performed to validate the effectiveness of the proposed system under various PS conditions. The results obtained are encouraging as the reconfiguration algorithm improves the efficiency of the SPWPS.

A Total-Cross-Tied-Based Dynamic Photovoltaic Array Reconfiguration for Water Pumping System

Most Photo-voltaic (PV) applications require a shadow-free area for the installation of the PV panels. However, shading is inevitable in a few applications like building-integrated PV pumping systems (BIPVPS). Partial shading occurs due to soiling, clouds, shades of nearby trees, buildings, current, and telephone poles. During this partial shading condition, the PV array output power decreases, reducing the efficiency of the BIPVPS. In this paper, a novel dynamic array reconfiguration technique is proposed to enhance the power output from the PV array. The proposed system uses a boost converter with an incremental conductance algorithm for operating enhanced power at the maximum. Sinusoidal Pulse Width Modulation (SPWM) technique based on <inline-formula> <tex-math notation="LaTeX">$V/f$ </tex-math></inline-formula> control operates the induction motor. Thus, the proposed algorithm and maximum power point technique (MPPT) enhance the power output from the PV array and track the global power. The PI and <inline-formula> <tex-math notation="LaTeX">$V/f$ </tex-math></inline-formula> control regulate the dc-link voltage and speed of the Induction motor. Simulations and experimental studies are performed to show the effectiveness of the proposed algorithm. The proposed system results in additional 234 W PV power extraction compared to the conventional system. Thus, making the proposed BIPVPS efficient.

Improved non-symmetrical puzzle reconfiguration scheme for power loss reduction in photovoltaic systems under partial shading conditions

The power output of photovoltaic arrays decreases because of mismatch losses when working under partial shading conditions, and various static reconfiguration techniques have been proposed to mitigate these losses. The non-symmetrical puzzle arrangement, as a static reconfiguration strategy proposed earlier, can use simple arithmetic operations to alter the physical location of photovoltaic panels without modifying the total-cross-tied based electrical connections. However, this arrangement has the disadvantage of poor shading effects and is unsuitable for large-size arrays. In this work, by introducing an odd–even configuration and redefining the shift distance, a systematic static reconfiguration method called the parity-column index is proposed to solve these problems. To verify the validity of the output characteristics, a 9 × 9 photovoltaic array output model was built using MATLAB/Simulink, and six shadow patterns were simulated. Furthermore, the proposed arrangements were compared with the total-cross-tied, odd–even, and non-symmetrical puzzle arrangements. The simulation results regarding the global maximum power point, power mismatch losses, percentage power loss, fill factor, and percentage power enhancement were analyzed separately, and the output characteristics of the above array reconfiguration methods were evaluated to verify the superiority of the proposed arrangement.

Investigation of Power losses on Solar Photovoltaic Array Interconnections Under Mismatch Conditions

The mismatch effect creates a difference between the sum of maximum power generated by individual Photovoltaic (PV) modules and the overall PV array power output. Mismatch effects can be classified into internal and external mismatch effects. Internal mismatch effect occurs because of factors such as manufacturing defects and ageing. The external effect occurs because of variations in solar irradiance and temperature. This paper presents the investigation of internal and external mismatch effects on various 5×4 Photovoltaic (PV) array interconnections such as series-parallel, total-cross-tied, bridge-link, honey-comb, hybrid SP-TCT, hybrid BL-TCT, along with proposed hybrid HC-TCT and hybrid HC-BL. Six mismatch case studies are considered in this paper to investigate the performance of PV array connections. Among the six cases, three cases are due to internal mismatch effects, and the remaining three cases belong to the external effects. In addition, the global maximum power point (GMPP), the voltage at GMPP, thermal voltage, power loss, fill-factor, efficiency (η), and possible local peaks (PLP) parameters are calculated and compared for each PV array connection under all case studies using Matlab-Simulink. Also, for each PV array connection, the revenue generation is calculated from energy savings under mismatch effects. The paper summary shows that TCT, HC-TCT, and HC-BL array connections delivered beneficial results under external effects, and TCT, HC, HC-TCT, and HC-BL provided superior results under internal effects.

Socio-inspired democratic political algorithm for optimal PV array reconfiguration to mitigate partial shading

Time-varying environment conditions have significantly influenced operation performance of photovoltaic generation. Partial shading condition is a typical problem which usually increases mismatch losses and reduces output power of photovoltaic array. For large-scale PV power plants, partial shading may affect the efficiency of the entire PV system. To solve this issue, this paper proposes a novel socio-inspired photovoltaic reconfiguration approach, called democratic political algorithm (DPA), which can effectively reduce power losses, improve power generation efficiency and accelerate convergence rate. DPA aims to reconfigure photovoltaic array’s electrical connection to minimize malignant impacts from partial shading condition and then obtain higher-quality output characteristics. Three case studies are carried out to verify the effectiveness and advantages of DPA, together with a thorough comparison of nine typical meta-heuristic algorithms. Simulation results demonstrate that DPA can enhance output power of photovoltaic array by 21.47% for a 10 × 10 (small) PV array, 21.55% for a 15 × 15 (medium) PV array, and 20.98% for a 20 × 20 (large) PV array compared to total cross tied interconnection scheme.

Performance characteristics of photovoltaic cold storage under composite control of maximum power tracking and constant voltage per frequency

A direct-driven photovoltaic refrigeration compressor usually operates in an unstable working state in the long term due to the fact that it is affected by intermittent solar irradiance. Hence, it is essential to control the compressor efficiently and appropriately. To ensure energy-saving and stable operation of photovoltaic refrigeration, we adopted a control method of photovoltaic maximum power point tracking combined with constant voltage per frequency for off-grid photovoltaic cold storage to achieve dynamic matching between the photovoltaic system and the load. A matching model of the optimum photovoltaic array output power and the optimized power with a certain temperature irradiance and standard test conditions was established. Based on the collaborative control method proposed herein, a 5.4-kW direct-driven cold storage system with a distributed photovoltaic system was established, and the performance characteristics of the photovoltaic cold storage were analysed. The results showed that the refrigeration system controlled using maximum power point tracking combined with constant voltage per frequency can efficiently track the optimal output power of the photovoltaic array and improve compressor utilisation in the direct-driven mode. The photoelectric conversion efficiency of the photovoltaic system reached 15.33%, which was closer to the nominal efficiency of the photovoltaic modules. Compared to the conventional maximum power point tracking control, the performance ratio of the photovoltaic system under the maximum power point tracking combined with constant voltage per frequency control improved by 9.18%. Such a typical off-grid solar photovoltaic cold storage system can use energy instantaneously, with optimal energy-saving effect.

Review of maximum power point tracking algorithms of PV system

PurposeSilicon photovoltaics technology has drawbacks of high cost and power conversion efficiency. In order to extract the maximum output power of the module, maximum power point (MPP) is used by implying the nonlinear behavior of I-V characteristics. Different techniques are used regarding maximum power point tracking (MPPT). The paper aims to review the techniques of MPPT used in PV systems and review the comparison between Perturb and Observe (P&amp;O) method and incremental conductance (IC) method that are used to track the maximum power and gives a comparative review of all those techniques.Design/methodology/approachA study of MPPT techniques for photovoltaic (PV) systems is presented. Matlab Simulink is used to find the MPP using P&amp;O simulation along with IC simulation at a steady temperature and irradiance.FindingsMATLAB simulations are used to implement the P&amp;O method and IC method, which includes a PV cell connected to an MPPT-controlled boost converter. The simulation results demonstrate the accuracy of the PV model as well as the functional value of the algorithms, which has improved tracking efficiency and dynamic characteristics. P&amp;O solution gave 94% performance when configured. P&amp;O controller has a better time response process. As compared to the P&amp;O method of tracking, the incremental conductance response rate was significantly slower.Originality/valueIn PV systems, MPPT techniques are used to optimize the PV array output power by continuously tracking the MPP under a variety of operating conditions, including cell temperature and irradiation level.

An Experimental Investigation on Photovoltaic Array Power Output Affected by the Different Partial Shading Conditions

This paper presents an experimental investigation on photovoltaic array (PV array) power output affected by partial shading conditions (PSCs). An experiment setup of a PV array with a series configuration using 2 × 4 photovoltaic modules (PV modules) was built. The power output loss due to the shading effect on the first photovoltaic cells (PV cell) connected with bypass diodes of each photovoltaic module, installed in the PV array in the horizontal direction, was evaluated. Depending on the direction of the sun relative to the PV array configuration, the shading percentage was measured during the test and recorded the current and voltage of the PV array. The performance evaluation of the PV array configurations is referred to with respect to the values of maximum power voltage, the maximum power current, maximum power output, power output losses and fill factor (FF). The experimental results show that 44% shading of the first PV cells affects PV array power output loss by more than 80%.

A Control Strategy for Dual-Input Neutral-Point-Clamped Inverter-Based Grid-Connected Photovoltaic System

This article presents a control strategy for a dual-input neutral-point-clamped (NPC) inverter-based grid-connected photovoltaic (PV) system to asymmetrically control the PV arrays without incorporating any additional external circuit. This is achieved by employing an analytically developed linearization block, which helps in generating the required neutral point (NP) current to counter for the difference in the PV currents. The analysis also provides the maximum NP current compensation limits of the NPC inverter. If the required NP current reference is less than the maximum limit, both PV arrays operate at their maximum power points. However, if the required current exceeds the limit, one of the PV arrays operates at its maximum power point, while the output power of the other PV array is reduced to satisfy the NP current limit. Experimental tests are conducted on a laboratory prototype to validate the performance of the proposed control strategy.

DC Voltage Utilization Improvement to Enlarge Power Balance Constraint Range for Photovoltaic Cascaded Inverter

In the three-phase photovoltaic (PV) cascaded inverter, the output power of PV arrays is not equal due to the difference of solar radiation, temperature and other factors, which leads to the over modulation of PV cascaded inverter. In order to solve the above problems, the carrier phase-shifted PWM (CPS-PWM) control strategy based on third harmonic injection is proposed in this paper, taking a single-stage high-frequency-link isolated cascaded PV inverter topology with clamping circuits as an example. It can not only improve the utilization of DC voltage, but also enlarge the power balance constraint range between the units in the phase of cascaded PV inverter, so as to ensure that all units can avoid over modulation under some serious power imbalance cases, and will not increase the third harmonic component injection of grid current. Firstly, the topology and working principle of the proposed inverter based on CPS-PWM control strategy are introduced. Then, the improved CPS-PWM control strategy which can improve the DC voltage utilization of the PV cascaded inverter is analyzed, and the control strategy of intra-phase power balance is emphatically analyzed in the overall control strategy of PV cascaded inverter system, and it is discussed that the proposed control strategy can also enlarge the power balance constraint range between the units of the cascaded inverter. Finally, the effectiveness of the proposed PV cascaded inverter based on the improved CPS-PWM control strategy is verified by the simulation and experimental results.

Improved Performance of an Asynchronous Motor Drive with a New Modified Incremental Conductance based MPPT Controller

This paper describes the improved performance of an asynchronous motor drive with a new modified Incremental conductance-based MPPT controller. In the last few decades, renewable energy sources are playing a dominant role in electricity generation as non-renewable energy sources are becoming extinguish and are the major cause of global warming. Photovoltaic (PV) energy is the most important energy resource since it is clean, pollution-free, and inexhaustible. Maximum power point tracking (MPPT) is used in photovoltaic systems to maximize the photovoltaic array output power with variable irradiances and variable temperature. The space vector modulation technique is used to reduce ripple content and fluctuation with improving efficiency. The algorithm used in MPPT is the Incremental Conductance method for a solar PV system to determine maximum output power.

Review of photovoltaic water pumping system research

Currently a considerable and the most economically justified potential of making the solar energy conversion more efficient and making the solar energy more attractive for consumers involves the coordination of the entire equipment from generation to consumption while considering all this equipment as a unified system and taking the degree of satisfaction of the consumer needs as the measure of efficiency. A photovoltaic water pumping system (PVWPS) is the first and one of few types of ground photovoltaic systems where the consumption equipment was always considered from the onset as part of the system. So a retrospective analysis of PVWPS research is of particular interest. This article contains the PVWPS research analysis beginning with the first research conducted in 1964–1966 to date. Discussed herein are the main problems that arose in the PVWPS development, operation, and optimization as well as options of their solution. Various areas of PVWPS improvement research were analyzed, including research involving photovoltaic array structure and photovoltaic modules interconnection; development and improvement of special structures of any components (pumps and invertors, etc.); improvement of photovoltaic array and electric motor interaction, electric motor and pump interaction against the backdrop of irradiance variation and in conjunction with consumption optimization and control improvement, to start with maximum power point tracing. It would make sense to aim further research involving cost reduction, productivity gain, and PVWPS service life extension at the expansion of the fields of PVWPS application, improvement of individual PVWPS components, and a more efficient use of water that is drawn. One of the prospective lines of PVWPS improvement and upgrading is to include them in the system of end user consumption equipment and assess the system efficiency not at the pump output and not in the point of end consumption equipment but after the water consumption. Studying PVWPS with the account of the fact that, in real conditions, the average output power of photovoltaic array depends not only on irradiance but also on the combined effect of all environmental conditions (climatic parameters, current state of atmosphere and air, surrounding objects, etc.) is of great importance, today.