scholarly journals An Adaptive Photovoltaic Topology to Overcome Shading Effect in PV Systems

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Mohamed Amer Chaaban ◽  
Lana El Chaar ◽  
Mahmoud Alahmad
Keyword(s):  
United Arab Emirates ◽  
Adaptive Systems ◽  
Adaptive System ◽  
System Size ◽  
Pv System ◽  
Pv Systems ◽  
System Solution ◽  
System Components ◽  
Active Research ◽  
Radiation Conditions

Shading in photovoltaic systems can cause many undesired effects. When shading occurs, the power generated from the PV system is much less than nominal power, increasing the electrical mismatching losses between PV system components. Active research to address this power loss focuses on static and adaptive systems. This paper addresses an adaptive system solution and proposes a new method to adaptively overcome losses due to shading during low radiation conditions. In addition, a statistical analysis for choosing the most feasible and efficient configuration for the system size is presented. The proposed system has been validated under shade conditions in a simulation and prototype experiment. The experiments are conducted using a PV system consisting of 10 PV modules located at the Petroleum Institute in the United Arab Emirates. The proposed system is shown to minimize the shading losses of the PV array in real time by an average of 100% under simulated conditions and 84% in practical experiments.

scholarly journals The Influence of Cleaning Frequency of Photovoltaic Modules on Power Losses in the Desert Climate

2020 ◽  
Vol 12 (22) ◽  
pp. 9750
Author(s):  
Ali Hasan Shah ◽  
Ahmed Hassan ◽  
Mohammad Shakeel Laghari ◽  
Abdulrahman Alraeesi
Keyword(s):  
United Arab Emirates ◽  
Geographical Location ◽  
Optimal Time ◽  
Integration Scheme ◽  
Time Interval ◽  
Power Losses ◽  
Pv System ◽  
Pv Systems ◽  
Radiation Losses ◽  
Al Ain

Dust accumulation on the photovoltaic (PV) surface decreases the solar radiation penetration to the PV cells and, eventually, the power production from the PV system. To prevent dust-based power losses, PV systems require frequent cleaning, the frequency of which depends on the geographical location, PV integration scheme, and scale of the PV power plant. This study aims to measure the drop-in radiation intensity, as well as power output, due to dust and to determine the optimal time interval for PV cleaning in the United Arab Emirates (UAE) climate. In this research, a dusting study experiment was carried out at the Renewable Energy Laboratory, Falaj Hazza Campus, UAE University, Al Ain, UAE, for 3.5 months, from 22 April 2018 to 7 August 2018. To measure the pure radiation losses caused by the dust, four transparent glasses were used to mimic the top glass cover of the PV modules. The dusting induced power losses were measured for four selected PV cleaning frequencies (10 days, 20 days, 1 month, and 3 months). This study revealed that up to 13% of power losses occurred in PV panels that remained dusty for 3 months, compared to panels that were cleaned daily. PV cleaning after 15 days brought the losses down to 4%, which was found the most feasible time for PV cleaning in this study, considering a reasonable balance between the cleaning cost and energy wasted due to soiling.

California’s Self-Generation Incentive Program Nonresidential PV Systems: Measured System Performance and Actual Costs

2006 ◽  
Author(s):  
Patrick Lilly ◽  
George Simons
Keyword(s):  
Power Output ◽  
System Performance ◽  
Energy Production ◽  
System Size ◽  
System Capacity ◽  
Operating Characteristics ◽  
Pv System ◽  
Peak Demand ◽  
Pv Systems ◽  
Incentive Program

More than two hundred sixty grid-tied photovoltaic (PV) systems sized 30 kW to 1.1 MW installed in California during 2002 through 2004 received partial funding through the Self-Generation Incentive Program (SGIP). The SGIP is administered statewide by PG&E, SCE, SoCalGas, and the San Diego Regional Energy Office. The incentive is structured as a one-time capacity based payment made at the time of system completion. The first PV system incentive was paid in Summer 2002. Through the end of 2004, a total of 269 PV systems had received financial support through the program. The cumulative generation capacity of these systems exceeded 30 MW and corresponded to $101 million of incentives paid. While originally slated to run through 2004, recently the program was modified and extended through the end of 2007. PV systems participating in the program are being monitored to support evaluation of the program. These data have been used to assess impacts of the Program on peak demand and energy consumption. These data have also been incorporated into the Program’s cost-effectiveness assessment. Well over one-half of the PV systems have already been subject to metering yielding 15-minute interval generator output data. The cumulative size of the directly monitored PV systems currently exceeds 33 MW as of late 2005. In 2004, the statewide California Independent System Operator (ISO) electrical system peak occurred on September 8 during the 16th hour (from 3 to 4 PM PDT). During this hour the electrical demand for the California ISO reached 45,562 MW. On this day, there were 235 PV systems funded under the SGIP installed and operating; interval-metered data are available for 107 of these projects. The resulting estimate of peak demand impact coincident with the ISO peak load totals 9,938 kW. The estimated peak demand impact corresponds to 0.39 kW per 1.0 kWRebated of PV system size and is based on rebated capacity. Those unfamiliar with PV system size ratings and PV system operating characteristics may be surprised that the overall weighted-average peak demand impact was not substantially higher at this hour and time of year. To help put this result in perspective, it can be compared to a simple engineering estimate of peak power output based on published information regarding PV system performance. First, we begin with 1 kW [basis: rebated size] of horizontal PV system capacity. For purposes of determining rebates, PV system sizes are calculated as the product of cumulative estimated module DC power output under PTC conditions and inverter maximum DC to AC conversion efficiency. Factors such as manufacturing tolerance, soiling, module mismatch, temperature effects, and wiring losses may result in actual full-sun power output levels of about 0.76 kW/kWRebated. When the 3 to 4 PM angle of incidence effects for the month of September are included the expected output value drops significantly further. The peak-day operating characteristics of the 107 PV projects for which peak-day interval-metered data were available are summarized in the box plot of Figure 4. System sizes were used to normalize power output values prior to plotting summary statistics of PV output profiles for individual projects. The normalized values represent PV power output per unit of system size. Treatment in this manner enables direct comparison of the power output characteristics of PV systems of varying sizes. The vertically oriented boxes represent ranges within which 75% of project-specific values lie. The vertical lines represent the total range (i.e., maximum and minimum) of project-specific values. The energy production of the group of metered PV systems varied according to season. In Figure 7, normalized energy production by month is illustrated (on the right axis). These values represent the monthly average capacity factor for the on-line PV system capacity. As expected, normalized energy production levels reach their maximum values in the summer season and decrease towards the winter season as the intensity and duration of incident solar radiation falls off, coupled with increased incidence of storms and other weather disturbances off the Pacific Ocean, which affect the availability of solar radiation upon the PV modules.

An interactive system for remote modelling and design validation of hybrid photovoltaic systems

2014 ◽  
Vol 31 (3) ◽  
pp. 224-228 ◽  
Author(s):  
Wojciech Grzesiak ◽  
Krzysztof Witek ◽  
Ewa Klugmann-Radziemska ◽  
Paweł Grzesiak
Keyword(s):  
Fuel Cells ◽  
Block Diagram ◽  
Interactive System ◽  
System Modelling ◽  
Technical Solution ◽  
Thermoelectric Generators ◽  
Pv System ◽  
Content Type ◽  
Pv Systems ◽  
System Solution

Purpose – The purpose of this paper is to report the system solution expressed in the form of a block diagram. In this paper, a multi-functional demonstrator of the interactive system designed to modelling, monitoring and validation of hybrid photovoltaic (PV) systems assisted by fuel cells and thermoelectric generators is presented. Technical parameters of demonstrator components such as: silicon PV modules, fuel cells, thermoelectric generators, gel batteries, control and monitoring systems are described. Design/methodology/approach – The design shows the implementation of PV system modelling by four universal PV module simulators supported by two 65 W fuel cell and 12 modules, 6 W thermoelectric generators battery. Findings – The paper provides practical proof that the combination of PV technology with both thermoelecric generators and fuel cells technologies shows promising results for the development of hybrid PV systems with increased effectiveness and efficiency. Research limitations/implications – The design idea can be developed for many applications gaining electricity from many distributed sources of wasted energy. Practical implications – In practice, hybrid systems can be used to support the operation of classic PV systems, for example, working in various climatic conditions. Originality/value – The proposed model demonstrates new technical solution leading to the enlargement of the PV systems application.

Adaptive control of time-varying non-linear plants by speed-gradient algorithms

2019 ◽  
pp. 37-44 ◽  
Author(s):  
O. P. Tomchina ◽  
D. N. Polyakhov ◽  
O. I. Tokareva ◽  
A. L. Fradkov
Keyword(s):  
Adaptive Control ◽  
Adaptive Systems ◽  
Reference Model ◽  
Maximum Deviation ◽  
Model Parameters ◽  
Time Varying ◽  
System Solution ◽  
Non Linear ◽  
Initial Uncertainty ◽  
Speed Gradient

Introduction: The motion of many real world systems is described by essentially non-linear and non-stationary models. A number of approaches to the control of such plants are based on constructing an internal model of non-stationarity. However, the non-stationarity model parameters can vary widely, leading to more errors. It is only assumed in this paper that the change rate of the object parameters is limited, while the initial uncertainty can be quite large.Purpose: Analysis of adaptive control algorithms for non-linear and time-varying systems with an explicit reference model, synthesized by the speed gradient method.Results: An estimate was obtained for the maximum deviation of a closed-loop system solution from the reference model solution. It is shown that with sufficiently slow changes in the parameters and a small initial uncertainty, the limit error in the system can be made arbitrarily small. Systems designed by the direct approach and systems based on the identification approach are both considered. The procedures for the synthesis of an adaptive regulator and analysis of the synthesized system are illustrated by an example.Practical relevance: The obtained results allow us to build and analyze a broad class of adaptive systems with reference models under non-stationary conditions.

scholarly journals Reconfigurable Distributed Power Electronics Technique for Solar PV Systems

Electronics ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1121
Author(s):  
Kamran Ali Khan Niazi ◽  
Yongheng Yang ◽  
Tamas Kerekes ◽  
Dezso Sera
Keyword(s):  
Energy Yield ◽  
Solar Pv ◽  
Charge Redistribution ◽  
Pv System ◽  
Partial Shading ◽  
Pv Systems ◽  
Simulation Based ◽  
In Series ◽  
A Cell ◽  
Power Balancing

A reconfiguration technique using a switched-capacitor (SC)-based voltage equalizer differential power processing (DPP) concept is proposed in this paper for photovoltaic (PV) systems at a cell/subpanel/panel-level. The proposed active diffusion charge redistribution (ADCR) architecture increases the energy yield during mismatch and adds a voltage boosting capability to the PV system under no mismatch by connected the available PV cells/panels in series. The technique performs a reconfiguration by measuring the PV cell/panel voltages and their irradiances. The power balancing is achieved by charge redistribution through SC under mismatch conditions, e.g., partial shading. Moreover, PV cells/panels remain in series under no mismatch. Overall, this paper analyzes, simulates, and evaluates the effectiveness of the proposed DPP architecture through a simulation-based model prepared in PSIM. Additionally, the effectiveness is also demonstrated by comparing it with existing conventional DPP and traditional bypass diode architecture.

scholarly journals State-Space Model of Quasi-Z-Source Inverter-PV Systems for Transient Dynamics Studies and Network Stability Assessment

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4150
Author(s):  
Lluís Monjo ◽  
Luis Sainz ◽  
Juan José Mesas ◽  
Joaquín Pedra
Keyword(s):  
Power Systems ◽  
State Space ◽  
State Space Model ◽  
Pv System ◽  
Pv Systems ◽  
Renewable Power ◽  
Ac Networks ◽  
Transient Interactions ◽  
The Stability ◽  
Averaged Model

Photovoltaic (PV) power systems are increasingly being used as renewable power generation sources. Quasi-Z-source inverters (qZSI) are a recent, high-potential technology that can be used to integrate PV power systems into AC networks. Simultaneously, concerns regarding the stability of PV power systems are increasing. Converters reduce the damping of grid-connected converter systems, leading to instability. Several studies have analyzed the stability and dynamics of qZSI, although the characterization of qZSI-PV system dynamics in order to study transient interactions and stability has not yet been properly completed. This paper contributes a small-signal, state-space-averaged model of qZSI-PV systems in order to study these issues. The model is also applied to investigate the stability of PV power systems by analyzing the influence of system parameters. Moreover, solutions to mitigate the instabilities are proposed and the stability is verified using PSCAD time domain simulations.

scholarly journals Analysis and Design of a Multi-Port DC-DC Converter for Interfacing PV Systems

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1943
Author(s):  
Bader N. Alajmi ◽  
Mostafa I. Marei ◽  
Ibrahim Abdelsalam ◽  
Mohamed F. AlHajri
Keyword(s):  
High Frequency ◽  
Computer Aided Design ◽  
Electromagnetic Transients ◽  
Pv System ◽  
Analysis And Design ◽  
Pv Systems ◽  
Point Tracking ◽  
Power Point Tracking ◽  
Power Point ◽  
Aided Design

A high-frequency multi-port (HFMP) direct current (DC) to DC converter is presented. The proposed HFMP is utilized to interface a photovoltaic (PV) system. The presented HFMP is compact and can perform maximum power point tracking. It consists of a high-frequency transformer with many identical input windings and one output winding. Each input winding is connected to a PV module through an H-bridge inverter, and the maximum PV power is tracked using the perturb and observe (P&O) technique. The output winding is connected to a DC bus through a rectifier. The detailed analysis and operation of the proposed HFMP DC-DC converter are presented. Extensive numerical simulations are conducted, using power system computer aided design (PSCAD)/electromagnetic transients including DC (EMTDC) software, to evaluate the operation and dynamic behavior of the proposed PV interfacing scheme. In addition, an experimental setup is built to verify the performance of the HFMP DC-DC converter.

scholarly journals An Optimized PV Control System Based on the Emperor Penguin Optimizer

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 751
Author(s):  
Mariam A. Sameh ◽  
Mostafa I. Marei ◽  
M. A. Badr ◽  
Mahmoud A. Attia
Keyword(s):  
Duty Cycle ◽  
Optimization Technique ◽  
Pso Algorithm ◽  
Boost Converter ◽  
Emperor Penguin ◽  
Pv System ◽  
Partial Shading ◽  
Pv Systems ◽  
Point Tracking ◽  
Grid Connected Inverter

During the day, photovoltaic (PV) systems are exposed to different sunlight conditions in addition to partial shading (PS). Accordingly, maximum power point tracking (MPPT) techniques have become essential for PV systems to secure harvesting the maximum possible power from the PV modules. In this paper, optimized control is performed through the application of relatively newly developed optimization algorithms to PV systems under Partial Shading (PS) conditions. The initial value of the duty cycle of the boost converter is optimized for maximizing the amount of power extracted from the PV arrays. The emperor penguin optimizer (EPO) is proposed not only to optimize the initial setting of duty cycle but to tune the gains of controllers used for the boost converter and the grid-connected inverter of the PV system. In addition, the performance of the proposed system based on the EPO algorithm is compared with another newly developed optimization technique based on the cuttlefish algorithm (CFA). Moreover, particle swarm optimization (PSO) algorithm is used as a reference algorithm to compare results with both EPO and CFA. PSO is chosen since it is an old, well-tested, and effective algorithm. For the evaluation of performance of the proposed PV system using the proposed algorithms under different PS conditions, results are recorded and introduced.

scholarly journals A Modification of the Perturb and Observe Method to Improve the Energy Harvesting of PV Systems under Partial Shading Conditions

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2521
Author(s):  
Alfredo Gil-Velasco ◽  
Carlos Aguilar-Castillo
Keyword(s):  
Maximum Power ◽  
Global Maximum ◽  
Pv System ◽  
Maximum Power Point ◽  
Partial Shading ◽  
Pv Systems ◽  
Point Tracking ◽  
Power Point Tracking ◽  
Power Point ◽  
Computational Resources

There are multiples conditions that lead to partial shading conditions (PSC) in photovoltaic systems (PV). Under these conditions, the harvested energy decreases in the PV system. The maximum power point tracking (MPPT) controller aims to harvest the greatest amount of energy even under partial shading conditions. The simplest available MPPT algorithms fail on PSC, whereas the complex ones are effective but require high computational resources and experience in this type of systems. This paper presents a new MPPT algorithm that is simple but effective in tracking the global maximum power point even in PSC. The simulation and experimental results show excellent performance of the proposed algorithm. Additionally, a comparison with a previously proposed algorithm is presented. The comparison shows that the proposal in this paper is faster in tracking the maximum power point than complex algorithms.

scholarly journals Method for Sizing of a PV System for Family Home Using Economic Indicators

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4529
Author(s):  
Zvonimir Šimić ◽  
Danijel Topić ◽  
Ilija Crnogorac ◽  
Goran Knežević
Keyword(s):  
Input Data ◽  
Net Present Value ◽  
Market Price ◽  
System Size ◽  
Electricity Price ◽  
Economic Indicators ◽  
Solar Irradiation ◽  
Pv System ◽  
Output Data ◽  
Levelized Cost Of Electricity

This paper presents a method for finding an optimal photovoltaic (PV) system according to Croatian legislation. The PV sizing model, in which a decision on investment is made according to economic indicators, is made using MATLAB Software. Based on the input data, the monthly PV system production is calculated, and electricity price formed. According to the PV system production and electricity price, economic indicators are calculated and obtained as output data. The model input data are solar irradiation, load diagram, PV system costs and market price of electricity while the model output data are PV system production, savings, profit, incomes, Net Present Value (NPV) and Levelized Cost of Electricity (LCOE). The obtained economic indicators are presented graphically and used for decision making on an optimal PV system size. The presented model is applied and presented in a case study.

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