Showing papers on "Maximum power point tracking published in 2016"

A New MPPT Design Using Grey Wolf Optimization Technique for Photovoltaic System Under Partial Shading Conditions

Abstract: This paper presents a maximum power point tracking (MPPT) design for a photovoltaic (PV) system using a grey wolf optimization (GWO) technique. The GWO is a new optimization method which overcomes the limitations such as lower tracking efficiency, steady-state oscillations, and transients as encountered in perturb and observe (P&O) and improved PSO (IPSO) techniques. The problem of tracking the global peak (GP) of a PV array under partial shading conditions (PSCs) is attempted employing the GWO-based MPPT technique. The proposed scheme is studied for a PV array under PSCs which exhibits multiple peaks and its tracking performance is compared with that of two MPPT algorithms, namely P&O-MPPT and IPSO-MPPT. The proposed GWO-MPPT algorithm is implemented on a PV system using MATLAB/SIMULINK. Furthermore, an experimental setup is developed to verify the efficacy of the proposed system. From the obtained simulation and experimental results, it is observed that the proposed MPPT algorithm outperforms both P&O and IPSO MPPTs.

Parameter estimation of solar photovoltaic (PV) cells: A review

Abstract: The contribution of solar photovoltaics (PV׳s) in generation of electric power is continually increasing. PV cells are commonly modelled as circuits. Finding appropriate circuit model parameters of PV cells is crucial for performance evaluation, control, efficiency computations and maximum power point tracking of solar PV systems. The problem of finding circuit model parameters of solar PV cells is referred to as “PV cell model parameter estimation problem,” and is highly attracted by researchers. In this paper, the existing research works on PV cell model parameter estimation problem are classified into three categories and the research works of those categories are reviewed. Based on the conducted review, some recommendations for future research are provided.

A review of conventional and advanced MPPT algorithms for wind energy systems

Abstract: Wind power is the most reliable and developed renewable energy source over past decades. With the rapid penetration of the wind generators in the power system grid, it is very essential to utilize the maximum available power from the wind and to operate the wind turbine (WT) at its maximal energy conversion output. For this, the wind energy conversion system (WECS) has to track or operate at the maximum power point (MPP). A decent variety of publication report on various maximum power point tracking (MPPT) algorithms for a WECS. However, making a choice on an exact MPPT algorithm for a particular case require sufficient proficiency because each algorithm has its own merits and demerits. For this reason, an appropriate review of those algorithms is essential. However, only a few attempts have been made in this concern. In this paper, different available MPPT algorithms are described for extracting maximum power which are classified according to the power measurement i.e. direct or indirect power controller. Merits, demerits and comprehensive comparison of the different MPPT algorithms also highlighted in the terms of complexity, wind speed requirement, prior training, speed responses, etc. and also the ability to acquire the maximal energy output. This paper serves as a proper reference for future MPPT users in selecting appropriate MPPT algorithm for their requirement.

Review of Active Power Decoupling Topologies in Single-Phase Systems

Abstract: Active power decoupling methods are developed to deal with the inherent ripple power at twice the grid frequency in single-phase systems generally by adding active switches and energy storage units. They have obtained a wide range of applications, such as photovoltaic (PV) systems, light-emitting diodes (LEDs) drivers, fuel cell (FC) power systems, and electric vehicle (EV) battery chargers, etc. This paper provides a comprehensive review of active power decoupling circuit topologies. They are categorized into two groups in terms of the structure characteristics: independent and dependent decoupling circuit topologies. The former operates independently with the original converter, and the latter, however, shares the power semiconductor devices with the original converter partially and even completely. The development laws for the active power decoupling topologies are revealed from the view of “duality principle,” “switches sharing,” and “differential connection.” In addition, the exceptions and special cases are also briefly introduced. This paper is targeted to help researchers, engineers, and designers to construct some new decoupling circuit topologies and properly select existing ones according to the specific application.

Maximum power point tracking (MPPT) techniques: Recapitulation in solar photovoltaic systems

Abstract: Unfilled gap of prolonged energy demand by conventional energy sources and consent of global warming as its vulnerable outcome provides a vent to search compatible option. Augmentation in use of solar energy reveled through last 3 decades portrays its heterogeneous rewards in the prevailing energy scenario. Nevertheless solar PV system arises as viable option in the critical power system era its low efficiency energy conversion attribute necessitates an efficient power conversion system. The nonlinearity of I–V (current–voltage) characteristic and its alteration for an assorted insolation and temperature values may enable the alteration in terminal voltage. This may deviates maximum power point due to which the available maximum power delivery to load can be differed. Literature of this field reiterated that the uniform insolation and partial shading condition demands undeniable need of maximum power point tracking. Nonetheless through investigation in this direction furnishes the availability of a bunch of such techniques; each of them posses its own pros and cones. This ubiquitous trait of available maximum power point tracking (MPPT) techniques unfolds the complexity in its precise selection. To diminish such complexity this paper offers a state of art of various MPPT technique and their comprehensive comparative analysis based on 110 standard research articles. The focus of this paper is to offer a better commencement and to furnish valued information for investigators of this field.

A Modified P&O Maximum Power Point Tracking Method With Reduced Steady-State Oscillation and Improved Tracking Efficiency

Abstract: This paper proposes a method to reduce the steady-state oscillation and to mitigate the probability of losing the tracking direction of the perturb and observed (P&O)-based maximum power point tracking (MPPT) for PV system. The modified scheme retains the conventional P&O structure, but with a unique technique to dynamically alter the perturbation size. At the same time, a dynamic boundary condition is introduced to ensure that the algorithm will not diverge from its tracking locus. The modified P&O is simulated in MATLAB Simulink and its performance is benchmarked using the standard MPPT efficiency ${{\boldsymbol{\eta }}_{MPPT}}$ calculation. Furthermore, the proposed concept is validated experimentally using a buck-boost converter, fed by a solar PV array simulator (PVAS). Based on the EN 50530 dynamic irradiance tests, the proposed method achieved an average ${{\boldsymbol{\eta }}_{MPPT}}$ almost 1.1% higher than the conventional P&O when irradiance changes slowly and about 12% higher under fast change of irradiance.

Mitigating methods of power fluctuation of photovoltaic (PV) sources – A review

Abstract: Renewable Energy Sources (RESs) particularly photovoltaic (PV) and wind are becoming important sources for power generation. Frequently varying output of PV and wind caused by clouds movement, weather condition and wind speed make them an intermittent and unreliable sources when connected to grid. Connecting intermittent sources to grid introduces challenges in various technical aspects such as power quality, protection, generation dispatch control and reliability. In this context, leveling intermittent source׳s output is necessary inorder to maintain grid׳s stability. This paper is aimed at bringing out the latest comprehensive literature review on problems associated when the intermittent PV is connected to grid and the methods of smoothing the output power fluctuation from PV. This paper also briefly discusses control strategy built for battery energy storage pertaining to this issue.

Trends and Challenges of Grid-Connected Photovoltaic Systems – A Review

Abstract: This paper presents a literature review of the recent developments and trends pertaining to Grid-Connected Photovoltaic Systems (GCPVS). In countries with high penetration of Distributed Generation (DG) resources, GCPVS have been shown to cause inadvertent stress on the electrical grid. A review of the existing and future standards that addresses the technical challenges associated with the growing number of GCPVS is presented. Maximum Power Point Tracking (MPPT), Solar Tracking (ST) and the use of transformless inverters can all lead to high efficiency gains of Photovoltaic (PV) systems while ensuring minimal interference with the grid. Inverters that support ancillary services like reactive power control, frequency regulation and energy storage are critical for mitigating the challenges caused by the growing adoption of GCPVS.

Power Balance of Cascaded H-Bridge Multilevel Converters for Large-Scale Photovoltaic Integration

Abstract: Multilevel cascaded H-bridge converters are promising candidates for large-scale photovoltaic power plants. They allow direct connection to medium-voltage distribution networks without the presence of bulky line frequency power transformers. Owing to the stochastically variable nature of irradiance level, ambient temperature, and other factors, power levels in the three phases are expected to be unequal. The power imbalance condition creates unexpected problems with this topology, which was initially designed to operate under balanced power conditions. To deal with this issue, the paper proposes three novel zero-sequence injection methods as an expansion to the conventional zero-sequence injection method. Results obtained from simulations and a 430-V 8-kW three-phase seven-level cascaded H-bridge prototype are presented to verify the effectiveness and feasibility of the proposed methods.

Active Management of Low-Voltage Networks for Mitigating Overvoltages Due to Photovoltaic Units

Abstract: In this paper, the overvoltage problems that might arise from the integration of photovoltaic (PV) panels into low-voltage (LV) distribution networks is addressed. A distributed scheme is proposed that adjusts the reactive and active power output of inverters to prevent or alleviate such problems. The proposed scheme is model-free and makes use of limited communication between the controllers in the form of a distress signal only during emergency conditions. It prioritizes the use of reactive power, while active power curtailment is performed only as a last resort. The behavior of the scheme is studied using dynamic simulations on a single LV feeder and on a larger network composed of 14 LV feeders. Its performance is compared with a centralized scheme based on the solution of an optimal power flow (OPF) problem, whose objective function is to minimize the active power curtailment. The proposed scheme successfully mitigates overvoltage situations due to high PV penetration and performs almost as well as the OPF-based solution with significantly less information and communication requirements.

Pinhole-free perovskite films for efficient solar modules

Abstract: We report on a perovskite solar module with an aperture area of 4 cm2 and geometrical fill factor of 91%. The module exhibits an aperture area power conversion efficiency (PCE) of 13.6% from a current–voltage scan and 12.6% after 5 min of maximum power point tracking. High PCE originates in pinhole-free perovskite films made with a precursor combination of Pb(CH3CO2)2·3H2O, PbCl2, and CH3NH3I.

State of the art artificial intelligence-based MPPT techniques for mitigating partial shading effects on PV systems – A review

Abstract: Given the considerable recent attention to distributed power generation and interest in sustainable energy, the integration of photovoltaic (PV) systems to grid-connected or isolated microgrids has become widespread. In order to maximize power output of PV system extensive research into control strategies for maximum power point tracking (MPPT) methods has been conducted. According to the robust, reliable, and fast performance of artificial intelligence-based MPPT methods, these approaches have been applied recently to various systems under different conditions. Given the diversity of recent advances to MPPT approaches a review focusing on the performance and reliability of these methods under diverse conditions is required. This paper reviews AI-based techniques proven to be effective and feasible to implement and very common in literature for MPPT, including their limitations and advantages. In order to support researchers in application of the reviewed techniques this study is not limited to reviewing the performance of recently adopted methods, rather discusses the background theory, application to MPPT systems, and important references relating to each method. It is envisioned that this review can be a valuable resource for researchers and engineers working with PV-based power systems to be able to access the basic theory behind each method, select the appropriate method according to project requirements, and implement MPPT systems to fulfill project objectives.

Maximum power point tracking algorithms for photovoltaic system – A review

Abstract: This paper provides a comprehensive review on various maximum power point tracking (MPPT) algorithms based on Perturb and Observe, Incremental Conductance, Soft Computing and other techniques along with the real time hardware implementation of photovoltaic (PV) system. In this review, the complete procedure, the implementation methodology and their effects in the PV output were discussed in detail for each algorithm. Further, MPPT algorithms for PV systems with partial shading condition were reviewed and reported. This paper is intended to serve as a suitable reference for future work in PV based power generation and its related research.

Z-Source Inverter: Topology Improvements Review

Abstract: One of the most promising power electronics converter topologies is the Z-source inverter (ZSI). The ZSI is an emerging topology for power electronics dc?ac converters with interesting properties such as buck-boost characteristics and single-stage conversion. A two-port network, composed of two capacitors and two inductors connected in an X shape, is employed to provide an impedance source (Z-source) network, coupling the inverter main circuit to the dc input source. The ZSI advantageously uses the shoot-through (ST) state to boost the input voltage, which improves the inverter reliability and enlarges its application fields. In comparison with other power electronics converters, it provides an attractive single stage dc?ac conversion with buck-boost capability with reduced cost, reduced volume, and higher efficiency due to a lower component number. For emerging power-generation technologies, such as fuel cells, photovoltaic (PV) arrays, and wind turbines, and new power electronic applications such as electric and hybrid vehicles, the ZSI is a very promising and competitive topology [1]-[4].

LMF-Based Control Algorithm for Single Stage Three-Phase Grid Integrated Solar PV System

Abstract: This paper proposes the use of a least mean fourth (LMF)-based algorithm for single-stage three-phase grid-integrated solar photovoltaic (SPV) system. It consists of an SPV array, voltage source converter (VSC), three-phase grid, and linear/nonlinear loads. This system has an SPV array coupled with a VSC to provide three-phase active power and also acts as a static compensator for the reactive power compensation. It also conforms to an IEEE-519 standard on harmonics by improving the quality of power in the three-phase distribution network. Therefore, this system serves to provide harmonics alleviation, load balancing, power factor correction and regulating the terminal voltage at the point of common coupling. In order to increase the efficiency and maximum power to be extracted from the SPV array at varying environmental conditions, a single-stage system is used along with perturb and observe method of maximum power point tracking (MPPT) integrated with the LMF-based control technique. The proposed system is modeled and simulated using MATLAB/Simulink with available simpower system toolbox and the behaviour of the system under different loads and environmental conditions are verified experimentally on a developed system in the laboratory.

Development of an Improved P&O Algorithm Assisted Through a Colony of Foraging Ants for MPPT in PV System

Abstract: The perturb and observe (P&O) algorithm is a simple and efficient technique, and is one of the most commonly employed maximum power point (MPP) tracking (MPPT) schemes for photovoltaic (PV) power-generation systems. However, under partially shaded conditions (PSCs), P&O method miserably fails to recognize global MPP (GMPP) and gets trapped in one of the local MPPs (LMPPs). This paper proposes ant-colony-based search in the initial stages of tracking followed by P&O method. In such a hybrid approach, the global search ability of ant-colony optimization (ACO) and local search capability of P&O method are integrated to yield faster and efficient convergence. A theoretical analysis of the static and dynamic convergence behavior of the proposed algorithm is presented together with computed and measured results.

A Simulated Annealing Global Maximum Power Point Tracking Approach for PV Modules Under Partial Shading Conditions

Abstract: This paper proposes a simulated annealing (SA)-based global maximum power point tracking (GMPPT) technique designed for photovoltaic (PV) systems which experience partial shading conditions (PSC). The proposed technique is compared with the common perturb and observe MPPT technique and the particle swarm optimization method for GMPPT. The performance is assessed by considering the time taken to converge and the number of sample cases where the technique converges to the GMPP. Simulation results indicate the improved performance of the SA-based GMPPT algorithm, with arbitrarily selected parameters, in tracking to the global maxima in a multiple module PV system which experiences PSC. Experimental validation of the technique is presented based on PV modules that experience nonuniform environmental conditions. Additionally, studies regarding the influence of the key parameters of the SA-based algorithm are described. Simulation and experimental results verify the effectiveness of the proposed GMPPT method.

High-Performance Constant Power Generation in Grid-Connected PV Systems

Abstract: An advanced power control strategy by limiting the maximum feed-in power of PV systems has been proposed, which can ensure a fast and smooth transition between maximum power point tracking and constant power generation (CPG). Regardless of the solar irradiance levels, high-performance and stable operation are always achieved by the proposed control strategy. It can regulate the PV output power according to any set point, and force the PV systems to operate at the left side of the maximum power point without stability problems. Experimental results have verified the effectiveness of the proposed CPG control in terms of high accuracy, fast dynamics, and stable transitions.

An Adaptive Network-Based Reinforcement Learning Method for MPPT Control of PMSG Wind Energy Conversion Systems

Abstract: This paper proposes an artificial neural network (ANN)-based reinforcement learning (RL) maximum power point tracking (MPPT) algorithm for permanent-magnet synchronous generator (PMSG)-based variable-speed wind energy conversion systems (WECSs). The proposed MPPT algorithm first learns the optimal relationship between the rotor speed and electrical power of the PMSG through a combination of the ANNs and the Q-learning method. The MPPT algorithm is switched from the online RL to the optimal relation-based online MPPT when the maximum power point is learned. The proposed online learning algorithm enables the WECS to behave like an intelligent agent with memory to learn from its own experience, thus improving the learning efficiency. The online RL process can be reactivated any time when the actual optimal relationship deviates from the learned one due to the aging of the system or a change in the environment. Simulation and experimental results are provided to validate the proposed ANN-based RL MPPT control algorithm for a 5-MW PMSG-based WECS and a small emulated PMSG-based WECS, respectively.

High-Accuracy and Fast-Speed MPPT Methods for PV String Under Partially Shaded Conditions

Abstract: The photovoltaic (PV) string under partially shaded conditions exhibits complex output characteristics, i.e., the current–voltage $(I\mbox{--}V)$ curve presents multiple current stairs, whereas the power–voltage $(P\mbox{--}V)$ curve shows multiple power peaks. Thus, the conventional maximum power point tracking (MPPT) method is not acceptable either on tracking accuracy or on tracking speed. In this paper, two global MPPT methods, namely, the search–skip–judge global MPPT (SSJ-GMPPT) and rapid global MPPT (R-GMPPT) methods are proposed in terms of reducing the searching voltage range based on comprehensive study of $I\mbox{--}V$ and $P\mbox{--}V$ characteristics of PV string. The SSJ-GMPPT method can track the real maximum power point under any shading conditions and achieve high accuracy and fast tracking speed without additional circuits and sensors. The R-GMPPT method aims to enhance the tracking speed of long string with vast PV modules and reduces more than 90% of the tracking time that is consumed by the conventional global searching method. The improved performance of the two proposed methods has been validated by experimental results on a PV string. The comparison with other methods highlights the two proposed methods more powerful.

BLDC Motor-Driven Solar PV Array-Fed Water Pumping System Employing Zeta Converter

Abstract: This paper proposes a simple, cost-effective, and efficient brushless dc (BLDC) motor drive for solar photovoltaic (SPV) array-fed water pumping system. A zeta converter is utilized to extract the maximum available power from the SPV array. The proposed control algorithm eliminates phase current sensors and adapts a fundamental frequency switching of the voltage source inverter (VSI), thus avoiding the power losses due to high frequency switching. No additional control or circuitry is used for speed control of the BLDC motor. The speed is controlled through a variable dc link voltage of VSI. An appropriate control of zeta converter through the incremental conductance maximum power point tracking (INC-MPPT) algorithm offers soft starting of the BLDC motor. The proposed water pumping system is designed and modeled such that the performance is not affected under dynamic conditions. The suitability of proposed system at practical operating conditions is demonstrated through simulation results using MATLAB/Simulink followed by an experimental validation.

Electric vehicles charging using photovoltaic: Status and technological review

Abstract: The integration of solar photovoltaic (PV) into the electric vehicle (EV) charging system has been on the rise due to several factors, namely continuous reduction in the price of PV modules, rapid growth in EV and concerns over the effects of greenhouse gases. Despite the numerous review articles published on EV charging using the utility (grid) electrical supply, so far, none has given sufficient emphasis on the PV charger. With the growing interest in this subject, this review paper summarizes and update all the related aspects on PV–EV charging, which include the power converter topologies, charging mechanisms and control for both PV–grid and PV-standalone/hybrid systems. In addition, the future outlook and the challenges that face this technology are highlighted. It is envisaged that the information gathered in this paper will be a valuable one-stop source of information for researchers working in this topic.

Solar photovoltaic water pumping system - A comprehensive review

Abstract: Solar photovoltaic water pumping system (SPVWPS) has been a promising area of research for more than 50 years. In the early 70s, efforts and studies were undertaken to explore the possibility of SPVWPS as feasible, viable and economical mean of water pumping. SPVWPS consists of different components and parts associated with different fields of engineering like mechanical, electrical, electronics, computer, control and civil engineering. The interdisciplinary nature of the system attracted the researchers, in the past, from all these fields of engineering and has been contributed by them to make the system more efficient and cost-effective to meet water-pumping needs of human, livestock and irrigation. The detailed literature available suggests that the research work on SPVWPS is not confined to any particular field of engineering. This review paper is an attempt to give a comprehensive review of the literature available on SPVWPS from the year 1975 to the year 2014. The review work discusses the general classification of SPVWPS, historical background of solar pumping systems, various efforts undertaken by researchers working on the different aspects of SPVWPS and the present status of research on the topic. The literature review of the maximum power point tracking (MPPT) system, different types of pumps and motors and rating of photovoltaic (PV) panel, which affect the performance, efficiency and economy of the SPVWPS system, has been incorporated in detail.

Improved performance low-cost incremental conductance PV MPPT technique

Abstract: Variable-step incremental conductance (Inc.Cond.) technique, for photovoltaic (PV) maximum power point tracking, has merits of good tracking accuracy and fast convergence speed. Yet, it lacks simplicity in its implementation due to the mathematical division computations involved in its algorithm structure. Furthermore, the conventional variable step-size, based on the division of the PV module power change by the PV voltage change, encounters steady-state power oscillations and dynamic problems especially under sudden environmental changes. In this study, an enhancement is introduced to Inc.Cond. algorithm in order to entirely eliminate the division calculations involved in its structure. Hence, algorithm implementation complexity is minimised enabling the utilisation of low-cost microcontrollers to cut down system cost. Moreover, the required real processing time is reduced, thus sampling rate can be improved to fasten system response during sudden changes. Regarding the applied step-size, a modified variable-step size, which depends solely on PV power, is proposed. The latter achieves enhanced transient performance with minimal steady-state power oscillations around the MPP even under partial shading. For proposed technique's validation, simulation work is carried out and an experimental set up is implemented in which ARDUINO Uno board, based on low-cost Atmega328 microcontroller, is employed.

A review of topologies of three-port DC–DC converters for the integration of renewable energy and energy storage system

Abstract: The application of renewable energy such as solar photovoltaic (PV), wind and fuel cells is becoming increasingly popular because of the environmental awareness and advances in technology coupled with decreasing manufacturing cost. Power electronic converters are usually used to convert the power from the renewable sources to match the load demand and grid requirement to improve the dynamic and steady-state characteristics of these green generation systems, to provide the maximum power point tracking (MPPT) control, and to integrate the energy storage system to solve the challenge of the intermittent nature of the renewable energy and the unpredictability of the load demand. In order to improve the efficiency and the power density of the overall circuit, the use of a three-port DC–DC converter, which includes a DC input port for the renewable source, a bidirectional DC input port for the energy storage system, and a DC output port for supplying the load, is a preferable solution to the traditional method using two DC–DC converters: one for the renewable sources and another for the energy storage system. In recent years, many DC–DC three-port converters have been proposed and reported in the literature. Each of these converters has its own topology and operating principle, which results in different complexities, different numbers of components, different reliability and efficiency. In this paper, a comparison of the features of different topologies of three-port DC–DC converters that have been proposed by different research groups is reviewed briefly. This review can be used as a guide for the appropriate selection of the suitable topology to meet the particular requirement of a system. The paper also discusses the potential research extension of the topologies from three-port DC–DC converters to three-port DC–AC inverters and how the voltage gain of the non-isolated three-port DC–DC converter can be improved.

Simulation and experimental design of a new advanced variable step size Incremental Conductance MPPT algorithm for PV systems

Abstract: Improvement of the efficiency of photovoltaic system based on new maximum power point tracking (MPPT) algorithms is the most promising solution due to its low cost and its easy implementation without equipment updating Many MPPT methods with fixed step size have been developed However, when atmospheric conditions change rapidly , the performance of conventional algorithms is reduced In this paper, a new variable step size Incremental Conductance IC MPPT algorithm has been proposed Modeling and simulation of different operational conditions of conventional Incremental Conductance IC and proposed methods are presented The proposed method was developed and tested successfully on a photovoltaic system based on Flyback converter and control circuit using dsPIC30F4011 Both, simulation and experimental design are provided in several aspects A comparative study between the proposed variable step size and fixed step size IC MPPT method under similar operating conditions is presented The obtained results demonstrate the efficiency of the proposed MPPT algorithm in terms of speed in MPP tracking and accuracy

Photovoltaic Hot-Spot Detection for Solar Panel Substrings Using AC Parameter Characterization

Abstract: Hot spotting is a problem in photovoltaic (PV) systems that reduces panel power performance and accelerates cell degradation. In present day systems, bypass diodes are used to mitigate hot spotting, but it does not prevent hot spotting or the damage it causes. This paper presents an active hot-spot detection method to detect hot spotting within a series of PV cells, using ac parameter characterization. A PV cell is comprised of series and parallel resistances and parallel capacitance, which are affected by voltage bias, illumination, and temperature. Experimental results have shown that when a PV string is under a maximum power point tracking control, hot spotting in a single cell results in a capacitance increase and dc impedance increase. The capacitance change is detectable by measuring the ac impedance magnitude in the 10–70 kHz frequency range. An impedance value change due to hot spotting can be detected by monitoring one high-frequency measurement in the capacitive region and one low-frequency measurement in the dc impedance region. Alternatively, the dc impedance can also be calculated using dc operating point measurements. The proposed hot-spot detection method can be integrated into a dc–dc power converter that operates at the panel or subpanel level.

Maximizing the Power Generation of a Partially Shaded PV Array

Abstract: As per energy efficiency of a photovoltaic (PV) system is concerned, partial shading is an important issue. Under partial shading condition, the modules of a PV array receive different levels of solar irradiation, so the power generation of a PV system decreases. The power–voltage characteristic of a partially shaded PV array contains multiple local maxima, and the global maximum power point is one of them. The losses in a PV array depend on the shading pattern and the physical location of shaded modules. This paper presents the Futoshiki puzzle pattern for the arrangement of the modules of a PV array under partial shading condition, ensuring the enhancement of the power generation with respect to totally crossed tired (TCT) structure. In this method, the physical locations of modules in a TCT structure PV array are rearranged without changing the electrical connection of the modules. A comparison between the power generation in TCT and Futoshiki puzzle pattern configuration is presented. It is demonstrated that the power generated by a PV array in the Futoshiki configuration method is enhanced, and mismatch loss (ML) is minimized under different shading patterns by theoretical, simulation, and experimental results.