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Solar power generation has increased exponentially in the last decade. It is expected to play an essential role in generating renewable energy in the United States and the world in the future. One of the critical points for the return on investment of photovoltaic systems is to maximize energy generation. Yet, a problem exists in that solar energy systems do not have a monitoring system for all components, so there is no way to know, in real-time, if the solar energy system is performing as expected. This study proposes to evaluate the effectiveness of the PVWatts prediction calculator compared to actual real-world data obtained from the Solar Energy Research Institute (Keshena, WI). The results show that the PVWatts prediction of solar energy generation is statistically significantly different from the actual solar energy generation. Moreover, the actual solar energy generation varies year by year, and the theoretical vs. actual analysis demonstrates that this system is not working according to warranty expectations. Therefore, there is a need for a real-time monitoring system or another type of real-time preventive maintenance to know the performance of solar systems. [ABSTRACT FROM AUTHOR]

The use of fossil fuels to generate energy produces greenhouse gases, which is the main factor in climate change. Solar energy is a clean source of energy that is environmentally friendly. The photovoltaic (PV) system is a well-established technology for converting solar energy into electrical energy. Sizing-decision of the PV system is a strategic decision-making process that has a long-term impact on the project. This work proposes an optimization model for the sizing decisions of the grid-connected PV system. The model considers the financial aspects in terms of minimizing project lifetime costs and the non-financial aspects in terms of reducing CO2 emissions and satisfying the planned service level. The decisions are the number of PV modules, the amount of energy purchased from the main grid, and the amount of energy supplied to the main grid. Besides an auxiliary binary variable for an either-or decision, either purchase-from or supply-to the grid. A case study is provided to clarify the model's practicality based on the residential area at King Fahd University of Petroleum & Minerals (KFUPM). It is found that 1,670 PV modules are required to meet the annual demand at an annual cost of M$1.45 over 25 years. [ABSTRACT FROM AUTHOR]

Purpose: This paper presents the development and implementation process of a service-oriented, economically viable business model that deals with the use of electricity from photovoltaic systems that are no longer state-subsidized. The research is funded within the context of the innovative research project “Citizen Energy Transition”, subsidized by the Ministry of Science, Research and the Arts Baden-Württemberg (funding code Kap. 1403 Titelgruppe75) Design/Methodology/Approach: First the catalyst for the innovative business model is investigated. Then the development and implementation process for the business model is explained and the business model itself. Findings: The end of the guaranteed feed-in tariff for the first photovoltaic systems leads to the necessity for new business models in the energy sector. Originality/Value: In design thinking workshops and ongoing feedback loops all stakeholders were involved in the development process. After refining and iteratively adapting the business model, it can be adjusted for further requirements due to regulative influences, customer needs, and ecological possibilities. [ABSTRACT FROM AUTHOR]

This article presents the contribution of the renewable energies to the energy mix in the network transmission of Senegal, western Africa. The focus will be on the capacity of this network to absorb a photovoltaic generation to determine the maximal penetration rate. The approach has been applied to the electricity network of SENELEC (National Company of Electricity of Senegal), which presents good opportunities to host photovoltaic energy production. The study investigates the maximum penetration rate of photovoltaic energy, which can avoid the network instability and considers two scenarios: (i) using storage systems and (ii) determining optimal size and best locations of PV plants through the network. The obtained simulation results show that by using storage systems of a capacity of 26 MW, the current maximum penetration rate of 20% corresponding to 120 MW PV can be increased up to 24%. It is also shown that a good choice of PV plants injection points can improve the penetration rate up to 24%, when the overall PV installed power 150 MW, without storage system. [ABSTRACT FROM AUTHOR]

Today, the grid frequency is predominantly controlled by conventional power plants. However, the increasing installed power of distributed energy resources and the declining amount of synchronous generators make it essential that wind farms as well as photovoltaic systems take over tasks of frequency control. Although photovoltaic systems are able to provide control reserve from a technical point of view, market and regulatory conditions are not designed for them to participate. Due to power electronics photovoltaic inverters are able to react even faster to frequency deviations than conventional power plants do. Using this characteristic, the contribution of photovoltaic systems to stabilizing the grid frequency is analyzed. Therefore, a new control reserve product, called fast Frequency Containment Reserves is developed. [ABSTRACT FROM AUTHOR]

This paper is focused on comparative analysis of photovoltaic (PV) monitoring system for observing the performance and stability of the system. The cost and complexity of existing PV monitoring systems restricted their use to large scale PV plants. Over the past decade, different aspects of the PV monitoring systems were reported in the wide range of literature. In this paper, a comparative analysis of various PV monitoring systems is presented for the first time. It is based on analyzing six main characteristics of PV monitoring system, such as data transfer mechanism, controller, monitoring parameters, sampling interval, program development software and monitoring methods. The comparison of methodologies and the description of implementation process are discussed in this context. The key findings of this study will contribute to the development of a new PV monitoring system. The acquaintance of all these aspects is crucial for the development of effective, low cost, and viable PV monitoring systems for the small and medium scale PV plants without compromising on the desired performance. [ABSTRACT FROM AUTHOR]

Global warming due to the excessive greenhouse gas emissions has led to the emergence of green technologies in Malaysia, particularly photovoltaic (PV) systems. Under the current regulatory framework, islanded operation of the PV system is not permissible. As a result, any renewable energy sources will be disconnected immediately in the event of grid outages. This practice is to ensure the safety of working personnel, as well as the customer equipment connected within the distribution networks. In addition, there is no synchronizing equipment to aid the reconnection of the islanded network to the grid. However, with the shutdown of the Distributed Generator (DG) during islanded operation, the customers are not able to utilize the available renewable energy and the number of power interruption is not improved with the renewable energy sources. Therefore, the main objective of this paper is to investigate the feasibility of the PV system in conducting islanding operation with the use of Energy Storage System (ESS). This paper also proposes a control algorithm to maintain the voltage and frequency excursion within the statutory limit by manipulating the real and reactive power flow of the ESS within the transition period between grid connected and islanding operation. [ABSTRACT FROM AUTHOR]

Solar photovoltaic system or solar power system is one of renewable energy system which uses PV modules to convert sunlight into electricity. The electricity generated can be either stored or used directly, fed back into grid line or combined with one or more other electricity generators or more renewable energy source. Solar PV system is very reliable and clean source of electricity that can suit a wide range of applications such as residence, industry, agriculture, livestock, etc. Investing in a solar PV system is a smart solution for an industry installations. The latest solar panels and photovoltaic (PV) systems are easy to install, maintain, and operate, with long-term performance and energy savings. Solar PV system includes different components that should be selected according to your system type, site location and applications. The major components for solar PV system are solar charge controller, inverter, battery bank, auxiliary energy sources and loads (appliances). The present paper aims to sizing PV systems in Algeria .This paper also gives a brief introduction of different technologies PV used. Followed by modelisation method for PV system. The obtained results are for an industry unit. [ABSTRACT FROM AUTHOR]

This study compares probability-of-exceedance values (P-values) for photovoltaic systems derived using multiple years of Vaisala's 3TIER Services weather data to those derived using a Typical Meteorological Year (TMY) based on the same resource data. Both approaches were used to estimate the year-1 yield of eighteen Megawatt-scale photovoltaic projects located in different parts of North America, South America and Asia. Pvalues in the TMY case were derived by using the standard deviation of annual global horizontal insolation as a proxy for inter-annual variability. All other uncertainties were treated identically in both approaches. Since our analysis included only eighteen case studies, we supplemented it by examining extreme cases where the differences between the two approaches should be maximum, namely cases where inter-annual variability dominates all other uncertainties. P50 values derived from a 3TIER Services TMY are usually within 0.5% of those derived using a full time series. Meanwhile, other P-values derived using a TMY exhibited a positive bias, indicating that this approach systematically underestimates uncertainty. A simple method for removing this bias was developed using ten projects as a training data set, and tested on the remaining eight projects. Overall, differences in P90 and P99 values are typically less than 1%, but can reach up to 2-5% in extreme cases. These results can serve as benchmarks for deciding whether and when TMY analysis is good enough. [ABSTRACT FROM AUTHOR]

The air-to-water heat pump (AWHP) system used to provide domestic hot water (DHW) for a passive house is a renewable technology with a high performance. The experimental measurements are used to test the performance of an AWHP system powered by electrical energy provided from a photovoltaic system. An energy consumption analysis for DHW production systems using air-to-water heat pump is performed. With the data from consumption analysis we can design and choose the photovoltaic system. The photovoltaic system must have the justified power in order not to oversize it. [ABSTRACT FROM AUTHOR]

In design and development of Wireless Sensor Networks (WSNs), one of the main challenges is to achieve long lasting battery lifetime. In this paper it is proposed model to estimate the reliability of the photovoltaic system in WSN. Modeling of the Loss of Load Probability (LOLP) parameter defines the system performance per month. [ABSTRACT FROM AUTHOR]

Excessive usages of fossil fuel as main energy source have become the main factor that contributes to the global warming. Carbon dioxide emissions from the combustion of fossil fuel increase the temperature of the atmosphere. Besides that, the depletion of this energy source also became a major factor to the world's energy crisis. As Malaysia move towards a developed country, energy requirement will remain very intensive. To prevent future problems of world energy crisis, Malaysia has embarked into renewable energy by introducing it as the Fifth Fuel Policy. The government would help out in terms of incentives, enabling policies and tax cuts for energy saving and efficient appliances and machinery. Since 2005 the Malaysian Energy Center (Pusat Tenaga Malaysia now known as the Green Tech Office) has been campaigning for the use of solar electricity with the help of the Danish Government via its implementation arm program known as DANIDA (from 2005 to 2010). This paper focuses on the three common types of solar panels available in the Malaysian market and to identify the most efficient in term of power conversion using the timer-tracking system by optimizing the sunlight and also to compare the performance between static system and dynamic system. Primarily for the Engineers and Architects, this research will help them identify critical technical factors in maximizing the energy output of different types of PV technologies at the same time consider the engineering and aesthetic issues associated with the roof mounted grid-connect PV system. [ABSTRACT FROM AUTHOR]

An increased utilization of renewable energy sources in the heat and electricity generation is one of priority tasks of the Slovak Republic to boost the use of domestic energy potential and thus to decrease the Slovakia's dependence on imported fossil fuels. Heat pumps and photovoltaics offer the most energy-efficient way to provide heating and cooling in many applications, as they can use renewable heat sources in our surroundings. The experimental workplace of our Faculty "Economic Research Centre for Renewable Energy Sources and Distribution systems" was founded with the purpose of investigating possibilities to reduce the energetic costs of buildings tied to economy. The realized project of the Centre creates real environment for effective implementation research of technologies in laboratory and operative conditions: technologies of cogenerative elements, heat pumps, photovoltaics elements, thermal capillaries, and technologies in field of measurement and regulation. The article discusses the issue of prediction of electric energy production using photovoltaic system. The procedure and results of photovoltaic system simulation model are subjected to comparisons between measurement, simulation and calculation methods. In regard to results of the comparison is established simulation model of produced electricity for the buildings. Within indoor environmental engineering system is installed in a building as a source of cooling. In conclusion, energy balance evaluated the electricity consumption coverage of heating and cooling system using photovoltaic system. [ABSTRACT FROM AUTHOR]

Nowadays, choosing of heating source is emphasized. On the market there are different types of heat sources, which need to be properly designed to the required heating output. Finally, it is necessary to take into account the possibilities of fuel burning as well as heat transfer substance. Heating system is dependent on regional weather conditions, where the building is located. All these factors ultimately, with proper design of the heat source, could reduce operating costs in the heating season. Currently in the design of the heating system, there are taken into account the greatest possible energy savings. It is therefore to encourage bigger utilization of renewable energy sources. Currently has the highest proportion of total energy consumption in the buildings, energy for heating and cooling. For this reason, the expert and research community seeks to reduce energy consumption at the lowest possible value. For this purpose, people are starting to apply renewable energy sources. These devices using renewable energy sources convert energy from the environment. Most of them are transforming energy from the sun, earth, water and air. This energy is then used directly for heating or cooling. In this article we will more closely deal with transforming solar energy into electricity using photovoltaic panels. This electric energy is used for heating and cooling system in the administrative building. On the other side, people living in the buildings want to reduce the energy consumption. In this article we focus on the interaction between the photovoltaic system and heating and cooling system, under certain weather conditions in the city of Košice in Slovakia [ABSTRACT FROM AUTHOR]

This paper discusses the control of the positive- and negative-sequence components of a large-scale grid-connected photovoltaic system (GCPS) under unbalanced voltage sag conditions in the grid. Some issues regarding stability and dynamic performance of the system occur when applying PI controllers in the current control loops. The reason is the delay that the filtering method imposes when extracting the current/voltage sequences. Because of such a delay, the dynamic response of the system becomes slower compared with the case when no filtering technique is needed. Furthermore, there is a strong restriction on choosing suitable parameters for the current/voltage loop controllers without compromising system stability. All these issues are discussed in this paper on a 1-MVA GCPV system using MATLAB/Simulink software. [ABSTRACT FROM PUBLISHER]

As the availability of solar energy varies widely with time and with different atmospheric condition, the cascaded multilevel inverters generates distorted output ac voltage and current if the generated PV voltages of each PV module are unequal. This paper proposes a novel space vector modulation technique for the single-phase cascaded H-bridge multilevel inverter (CHBMLI) to generate a balanced output voltage even under partial shadow condition of Photovoltaic (PV) module. In this topology each H-bridge cell of CHBMLI is connected to an individual PV module through a buck type DC-DC converter. This topology permits independent control of each PV module to operate them at maximum power point. It also offers other advantage such as lower current ripple compared to standard two-level topologies. The simulink model is developed using simpowersystem and simulink toolbox of MATLAB. [ABSTRACT FROM PUBLISHER]

Arc faults pose an extreme safety risk in already existing photovoltaic systems. In comparison to AC installations arc faults in photovoltaic systems have a significantly higher hazard potential. Missing zero-crossings of the current and the fact that a solar generator regarded as a source of energy cannot be switched off ensure much better conditions of existence for arc faults. The fundamental theoretical principles of DC arc faults in solar generators are described. In addition to that the main DC arc fault scenarios were classified in regards to their resulting risk for the whole photovoltaic system. Furthermore the special requirements of an arc generating unit for DC arc fault studies in real photovoltaic systems are characterized. The basic construction and use of a specifically designed arc fault generator for experimental investigations are described. In conclusion the first measurement results concerning the influence of arc faults on the source characteristic of the solar generator are presented. [ABSTRACT FROM PUBLISHER]

A novel power converter configuration for high power grid-connected photovoltaic (PV) systems is presented in this paper. It allows increasing the conversion efficiency with respect to a classical solution, based on centralized inverter, in whatever operating condition. In particular, the improvement of efficiency is due to both optimal power sharing algorithm and suitable interleaving modulation technique. [ABSTRACT FROM PUBLISHER]

This paper presents a novel maximum power point tracking (MPPT) algorithm, based on genetic algorithms (GA). This algorithm is used for searching the global maximum power point (GMPP) for photovoltaic systems affected by partial shading. The “Perturb and Observe” (P&O) algorithm is embedded into the GA function for improving the optimisation process. By adding this functionality to the algorithm, the number of iterations and the population size is low, thus finding the MPP in a short time. Description of this algorithm and its performances will be detailed in this article, verified through simulation and experimental results. [ABSTRACT FROM PUBLISHER]

As the output from the solar PV systems varies significantly with technologies, designs and prevailing weather parameters, their evaluation under actual field conditions is important in identifying their real performance characteristics. In this paper, comparative performances of six different PV systems connected to a 1.2 MWp grid integrated solar farm are presented. The solar technologies considered are the single crystalline (sc-Si), poly crystalline (mc-Si), micro crystalline (nc-Si/a-Si), amorphous silicon (a-Si), Copper Indium Selenium (CIS) and Heterojunction with Intrinsic Thin Layer (HIT). Following the IEA guidelines, the array yield, capture losses, array efficiency ratio, and performance ratio were taken as the criteria for the performance comparison. Among the six different module types, the systems based on amorphous silicon and HIT offer the best performance under the tropical environment considered. [ABSTRACT FROM PUBLISHER]

Today, the energy crisis in the world has led to the rise in use of renewable energy sources. With the advancement in power electronic technology, the solar photovoltaic energy has been recognized as an important renewable energy resource because it is clean, abundant and pollution free. The efficiency of the photovoltaic system may be increased by using Maximum Power Point Tracker (MPPT). A number of algorithms are developed to track the maximum power point efficiently. Most of the existing MPPT algorithms suffer from the drawback of being slow or wrong tracking. Introduction of intelligent MPPTs in PV systems is very promising. This paper proposes an intelligent control method for the maximum power point tracking (MPPT) of a photovoltaic system under variable insolation conditions. Here in this paper, intelligent control method uses a Fuzzy Logic Controller applied to a DC-DC converter device. The result is compared with the results obtained by using P&O method. The effectiveness of proposed algorithm is validated by simulation using Matlab/Simulink and is compared to those obtained by the conventional methods. The result shows that the fuzzy logic controller exhibits a better performance compared to that of conventional method. [ABSTRACT FROM PUBLISHER]

Photovoltaic energy harvesting systems (PV systems) are subject to PV cell faults, which decrease the efficiency of PV systems and even shorten the PV system lifespan. Manual PV cell fault detection and elimination are expensive and nearly impossible for remote PV systems, e.g., PV systems on satellites. Therefore, online fault detection techniques and fault tolerance solutions are needed that can detect and tolerate PV cell faults without manual intervention. In this work, we present an online fault detection and tolerance technique for remote PV systems, which is capable of dynamically locating faulty PV cells and tolerating PV cell faults. More precisely, we present a modified PV panel structure and an efficient algorithm for our online fault detection and tolerance. Our fault detection and tolerance technique reduces output power degradation due to PV cell faults in a PV system by up to 81.31%. [ABSTRACT FROM AUTHOR]

Nowadays, choosing of heating source is emphasized. On the market there are different types of heat sources, that need to be properly designed to the required heating output. Finally, it is necessary to take into account the possibilities of fuel burning as well as heat transfer substance. Heating system is dependent on regional weather conditions, where the building is located. All these factors ultimately, with proper design of the heat source, could reduce operating costs in the heating season. Currently in the design of the heating system, there are taken into account the greatest possible energy savings. It is therefore to encourage bigger utilization of renewable energy sources. Currently has the highest proportion of total energy consumption in the buildings, energy for heating and cooling. For this reason, the expert and research community seeks to reduce energy consumption at the lowest possible value. For this purpose, people are starting to apply renewable energy sources. These devices using renewable energy sources convert energy from the environment. Most of them are transforming energy from the sun, earth, water and air. This energy is then used directly for heating or cooling. In this article we will more closely deal with transforming solar energy into electricity using photovoltic panels. This electric energy is used for heating and cooling system in the administrative building. On the other side, people living in the buildings want to reduce the energy consumption. In this article we focus on the interaction between the photovoltic system and heating and cooling system, under certain weather conditions in the city of Kosice in Slovakia. A closer look at how weather affects the efficiency of photovoltic panels. [ABSTRACT FROM AUTHOR]

Partial shading is a serious obstacle to effective utilization of photovoltaic (PV) systems since it can result in significant output power degradation for the system. A PV system is organized as a series connection of PV modules, each module comprising of a number of series-parallel connected cells. This paper presents modified PV cell structures with integrated switches, imbalanced cell connection topologies for PV modules, and a dynamic programming algorithm to produce near-optimal reconfigurations of each PV module with the goal of maximizing the system output power level under any partial shading patterns. Through simulations, we have demonstrated up to a factor of 2.3X improvement in the output power level of a PV system comprised of 3 PV modules with 60 PV cells per module. [ABSTRACT FROM AUTHOR]

Partial shading is a serious obstacle to effective utilization of photovoltaic (PV) systems since it can result in significant output power degradation for the system. A PV system is organized as a series connection of PV modules, each module comprising of a number of series-parallel connected cells. This paper presents modified PV cell structures with integrated switches, imbalanced cell connection topologies for PV modules, and a dynamic programming algorithm to produce near-optimal reconfigurations of each PV module with the goal of maximizing the system output power level under any partial shading patterns. Through simulations, we have demonstrated up to a factor of 2.3X improvement in the output power level of a PV system comprised of 3 PV modules with 60 PV cells per module. [ABSTRACT FROM AUTHOR]

This paper presents a parameter identification strategy based on the d-q axis decoupling for a typical PV inverter, which contains double loop control model. This strategy can reduce the order of the model and improve the accuracy of the identification. Firstly, a typical PV grid-connected system model is built up, in which the inverter controller is based on the d-q axis decoupling current control. It's a double loop control including the outer voltage loop and the inner current loop, and the maximum power point tracking (MPPT). Secondly, we take the system as a research object, deduce the decoupling characteristics of the d-q axis parameters of the inverter controller through theoretical calculation, and reduce the order of the inverter model. Lastly, we get disturbance data through the simulation of control target reference step, and identify the parameters with the nonlinear damped least square method. The experimental results show that: the error is less than 5% in the dominant parameters of the inverter model, which proves the correctness and validity of the identification strategy. [ABSTRACT FROM PUBLISHER]

In this work the artificial neural networks (ANN) and the optimization algorithm of nonlinear damping least squares (Levenberg-Marquardt) were applied to estimate the generating power of photovoltaic system in China. And the MATLAB was applied to establish prediction model. Finally, the training samples were measured data of 30 days, 90 days and 180 days. Under the three samples, it researched generating output power forecasting of photovoltaic system. The predicted results show LMBP overcomes the shortcomings of BP neural network; it has better convergence and accuracy. After compare with all predicting data, predicting results of 30 days data is the most accurate among three training samples. [ABSTRACT FROM PUBLISHER]

Photovoltaic (PV) power systems have been widely applied in commercial and domestic facilities. Electrical energy storage (EES) systems are mandatory in standalone PV systems for continuous power supply. In this paper the efficiency and robustness enhancement methods for PV systems under partial shading have been investigated. Partial shading due to moving clouds and shadows of nearby obstacles on a PV module array causes significant efficiency degradation, since shaded and non-shaded PV modules have large discrepancy in their maximum power points (MPPs). Use of Individual charger for each PV module may mitigate the negative effect from partial shading. However, this method alone may still face severe energy efficiency degradation caused by i) the energy loss due to parasitic effects in the EES elements under variable incoming power from the PV modules and ii) the energy loss in each charger incurred by potentially high imbalance between its input and output voltages. This paper proposes three methods to enhance the PV system efficiency and robustness under partial shading: i) incorporation of a HEES (hybrid electrical energy storage) system into the PV system, ii) extension of the MPTT (maximum power transfer tracking) approach, and iii) dynamic PV module reconfiguration. The three proposed methods can be effectively combined together, yielding a significant efficiency gain ranging from 17.1% to 53.3% compared with the baseline systems. [ABSTRACT FROM PUBLISHER]

Many utilities are offering or plan to offer customers an option between standard and “Time-of-Day” (ToD) rates for electricity. Standard rates provide a flat rate for energy while the ToD rates are tiered. ToD rates are typically less than the standard rate during off-peak times and higher than the standard rate at peak times. This pricing structure can incentivize demand response (DR) and integration of photovoltaic (PV) generation. DR can shift energy consumption to off-peak times and PV generation typically coincides with peak rates. ToD pricing has the potential to reduce energy costs with DR and facilitate integration of PV energy sources. This paper presents results of a study on integrating a form of demand response and photovoltaic generation with ToD pricing. An example is presented on a residential home located in New York City Suburbs. Our findings for this example show that ToD pricing can be beneficial for customers that engage in Demand Response, however, nominal benefits are seen in conjunction with Photovoltaic energy sources. [ABSTRACT FROM PUBLISHER]

The paper describes the designing, sizing, realization and setting up of a complete system suitable for the management of an electrically power assisted velocipede using a photovoltaic module for the charging of the batteries. [ABSTRACT FROM PUBLISHER]

A family of inductorless forward-flyback converters utilizing dual constant on-time modulation is proposed, in order to maintain high efficiency over a wide load and input range. The main switch is turned on for the constant half resonant period to achieve zero-current-switching for the forward diode and to minimize the deadtime between the two output diodes. The auxiliary active switch is in the on-state with a very short constant interval to realize zero-voltage-switching for the main active switch, even if the magnetizing inductor operates in the continuous current mode. Experimental results for a 250 W hardware prototype verifies soft-switching operation from zero to full load over 25 to 45 V input range and the CEC weighted efficiency reaches 97%. The proposed converter is attractive for the tree-type PV system applications. [ABSTRACT FROM PUBLISHER]

Photovoltaic (PV) cell characteristics are highly nonlinear that gives single Maximum Power Point (MPP) on P-V curve under uniform insolation condition. The characteristics and hence MPP point changes with the variation in insolation and temperature. In order to extract a maximum power from PV array, a fuzzy based MPP tracking algorithm is proposed. The algorithm accepts single input that is slope of P-V curve and generates the duty ratio as an output that operates the boost converter to track MPP. The algorithm gives faster convergence by applying variable step in duty ratio and gives accurate MPP. The two stage grid interactive PV system described in this paper supplies active power as well as provides harmonic and reactive power compensation. This additional feature increases the effective utilization of PV inverter and increases the overall efficiency of the system. The simulation results validate the performance and stability of the grid interactive PV system using the proposed algorithm for active current injection as well as harmonics and reactive power compensation. [ABSTRACT FROM PUBLISHER]

In this paper the performance of three global peak power point tracking techniques are evaluated for grid-connected PV system operating under partially shaded conditions. The methods used for comparative study are (i) Perturb & observe (P&O) (ii) Incremental conductance (INC) and (iii) Fuzzy logic based. The comparison of performance is based on the study of simulation results obtained using MATLAB/SIMULINK. It is shown through the simulation study that the accurate tracking of peak power point under partially shaded condition increases the power extracted from the PV system. The simulation study reveals the superiority of the fuzzy logic based approach. [ABSTRACT FROM PUBLISHER]

Photovoltaic (PV) systems are renewable sources whose operating voltage and current are nonlinearly dependent on the temperature and sunlight intensity. Therefore, maximum power point (MPP) tracking is important for extracting as much power as possible from PV arrays. The Linear-line Approximation Method (LLAM) is able to converge to the MPP quickly regardless of the changes of sunlight intensity. However, the slope of the linear line method becomes non-optimal as the temperature changes, causing the PV systems to leave its MPP. This paper proposes a modified LLAM whose line slope can adapt automatically in response to temperature changes, maintaining an optimal MPP control. After verifying the feasibility and capability of the proposed algorithm by simulation, the proposed algorithm is further implemented as a microsystem in VLSI (Very Large Scale Integration). The application-specific VLSI is expected to achieve higher control efficiency and lower power consumption. [ABSTRACT FROM PUBLISHER]

Development of an effective maximum power point tracking (MPPT) algorithm is important in order to achieve maximum power point in a photovoltaic system (PV). In this study, a dynamic neural control (DNC) scheme is developed. The adaptation procedure is based on the back propagation learning law and is required only a priori knowledge, that's, the system output error. The feasibility of the proposed neural control is evaluated by the simulation results and compared to the conventional perturbation and observation (P&O) method. [ABSTRACT FROM PUBLISHER]

In this paper, the authors have investigated energy production estimation on large-scale time from photovoltaic power generation station in Southern Tunisia. The steady-state models of the photovoltaic system have been used. The evaluation for energy production estimation of the solar generating system is developed with the integration of photovoltaic modules losses and converters losses. The design of the photovoltaic system architecture according to the project site and according to metrological data was presented. The obtained results show that even with all losses integration the photovoltaic system remains an important solution to southern Tunisia. [ABSTRACT FROM PUBLISHER]

Using hybrid renewable energy is one of the best alternatives to supply the electrical energy at remote areas. Renewable energy sources are depended to weather conditions or other factors, so for supplying load with renewable sources appropriate capacity of these sources should be selected. In determining the capacity of renewable energy such as wind and solar, considering the stochastic nature of wind speed and solar radiation is very impressive. In this paper, a new algorithm for determining the capacity of hybrid wind, photovoltaic and battery generation system with considering the uncertainty in wind and photovoltaic power production is proposed. The algorithm of determining capacity of wind, photovoltaic and battery for supplying certain load is formulated as an optimization problem that the objective function is the minimization of the cost and with constrain of having specific reliability. Probability density of wind speed and solar radiation and Mont Carlo simulation method is used to considered uncertainty in wind and photovoltaic power generation. Particle swarm optimization is used for optimal sizing of the system. [ABSTRACT FROM PUBLISHER]

Afghanistan is a mountainous country with a significant amount of snow during the winter and once it melts the water runs into rivers, lakes and streams. Therefore it does not face any shortage of running water during the year. Also, Afghanistan has plentiful wind and solar energy potential. Therefore, small hydro-power, wind turbines and solar energy are attractive renewable energy sources for remote communities. The development of such a hybrid power system is a complex process. This paper will give an insight into design, cost-effectiveness and feasibility of a hybrid power system using Hybrid Optimization Model for Electric Renewable (HOMER) with two different scenarios in order to encourage private investors and local community people to take advantage of this potential available in Afghanistan and ensure sustainability of investments in micro-hydro power, wind and solar. [ABSTRACT FROM PUBLISHER]

In recent years, interest of using multilevel inverters have been increased. Among different types of multilevel inverters cascaded one is a good choice of power conditioning in renewable energy application, because of their simplicity, modularity, low switches voltage stress and less number of components. Different switching techniques have been proposed for equal power sharing between cells of multilevel inverter. Low order harmonics and inter harmonics in output voltage of multilevel inverter are problems caused by voltage ripple in dc link capacitors. For solving these problems, a large DC capacitor is needed which increases cost and size of the system and reduces lifetime and reliability. Among multilevel switching techniques, In Phase Disposition pulse width modulation (IDPPWM) have the lowest amount of harmonics. In this method power delivery of the inverter cells are not equal. In this paper a method that improves power sharing in IDPPWM is proposed for photovoltaic (PV) application. This method is compared with similar switching patterns in aspects of dc link voltage ripple and amount of DC link capacitor. The switching pattern is applied to a 7 level inverter in which each H-bridge or cell is connected to a PV array operated at maximum power point (MPP). The 7 level inverter supplies a standalone AC inductive load. Simulations are implemented using MATLAB/SIMULINK software and the results confirm effectiveness of the proposed method in balancing power sharing among different inverter cells and requiring smaller DC link capacitors. [ABSTRACT FROM PUBLISHER]

The high number of photovoltaic systems raises questions regarding their operational security even under extremely weather conditions like thunderstorms. Therefore a simplified model of a photovoltaic system, consisting of typical arrangement of solar-panels, was investigated. The influence of lightning strike was simulated by different lightning current shapes and striking points into the solar-panels. It was found, that besides the construction size and shape of the lightning current the striking point has a main influence on the value of induced overvoltages, occurring on the connection point of the solar-panels. The simulation results were confirmed by measurement with an impulse current. The results demonstrate the dangerousness of lightning currents with very fast rise time e.g. subsequent impulse as well as the reducing of induced overvoltages by an appropriate earthing connection. This has to be considered at the design of the lightning protection system. [ABSTRACT FROM PUBLISHER]

To utilize the maximum power generated by the solar panel, it is required to match its internal resistance with that of the load. Because it has nonlinear internal resistance which varies as the intensity of light falling on the panel varies. In this paper boost converter interface is used as Maximum Power Point Tracker (MPPT) to match the source with the load. The problem in using high frequency converter interface is that high frequency ripple interaction with Photovoltaic system. To reduce the ripple, Interleaved Boost Converter (IBC) is considered. The advantages of IBC compared to the conventional boost converter are low input ripple current, high efficiency, faster transient response, reduced electromagnetic emission and improved reliability. The performance of two cell IBC with non-coupled, coupled and inverse coupled inductors with R and RL loads has been presented in this paper. Comparative results have been presented with simulation results with the help of MATLAB software. [ABSTRACT FROM PUBLISHER]

This paper proposes a maximum power point tracking scheme using neural networks for a grid connected photovoltaic system. The system is composed of a photovoltaic array, a boost converter, a three phase inverter and grid. The neural network proposed can predict the required terminal voltage of the array in order to obtain maximum power. The duty cycle is calculated and the boost converter switches are controlled. Hysteresis current technique is applied on the three phase inverter so that the output voltage of the converter remains constant at any required set point. The complete system is simulated using MATLAB/SIMULINK software under sudden weather conditions changes. Results show accurate and fast response of the converter and inverter control and which leads to fast maximum power point tracking. [ABSTRACT FROM PUBLISHER]

The paper presents controller design for phase modulated full bridge topology based boost converter for Photovoltaic (PV) applications. Extraction of maximum power from PV panel is ensured by Phase Modulated Converter (PMC) while the controller used, utilizes Incremental Conductance (IC) techniques for computing operating Maximum Power Point (MPP) in a very simple and effective manner. Subsequently, MATLAB/Simulink model of PV panel, converter and control scheme are presented. Simulation results are analyzed in order to validate the performance of proposed controller under varying environmental conditions. Results derived shows efficient tracking of MPP by the designed controller under robust operation. [ABSTRACT FROM PUBLISHER]

Performance of photovoltaic (PV) systems installed in Southern California is analyzed. Measured power output of 400 PV sites, measured irradiation at 5 stations, and satellite-derived irradiation data are applied. Performance of the PV systems is estimated by using the satellite-derived irradiation data. Also, clear sky indices (kt) are obtained and compared for all these datasets. Over one year the largest hourly ramp was a 61% decrease based on the STC rating. The measured and satellite derived irradiation data are applied to evaluate the predictability of ramps. The effects of specific meteorological conditions, such as coastal marine layer clouds and frontal system effects, on occurrence of large ramps are investigated over the area. Satellite images are utilized to detect the weather condition for the days in which the ramps occurred. [ABSTRACT FROM PUBLISHER]

This paper describes ongoing research in the area of solar PV production forecasting intended to address a range of effects on the utility grid associated with high penetrations of PV. The ability to anticipate near-term — minutes ahead to hours ahead to day or multiple-day ahead- production of the variable solar resource will be key to successfully integrating ever larger PV capacities with minimal costs. A number of forecast methodologies are surveyed and a mechanism for validating their performance is described. [ABSTRACT FROM PUBLISHER]

This study compares the reliability performance of string inverter structure and central inverter structure for grid-tied solar photovoltaic (PV) systems. The impact of input power variation and ambient-conditions on failure rates of PV system components are quantified and incorporated in the reliability analysis. Aging failure in PV panels is also modeled to evaluate the life cycle reliability of both types of PV systems. Sensitivity analyses are extensively conducted to explore the impact of different factors on the performances of different PV systems. Test results on a practical 20 kW PV project are presented to demonstrate the effectiveness of the presented method. [ABSTRACT FROM PUBLISHER]

Today we are witness the transition from testing stage to pre-marketing of concentration photovoltaic systems, mainly for it efficiency in term of electricity production. Latest generation of systems hereby called Concentrated PhotoVoltaic (CPV) systems are has reached industrial maturity, being able to take advantage and make use of high-efficiency cells: III-V multi-junction cells. In this paper a Fresnel lenses device will be described and compared to a traditional PV system. [ABSTRACT FROM PUBLISHER]

Photovoltaic (PV) cell characteristics are highly nonlinear that are affected by varying insolation and temperature condition. In case of uniform insolation condition, the P-V curve shows single maximum power point (MPP), but under partially shaded conditions, the P-V characteristic shows multiple peaks. Therefore, the maximum power point tracking (MPPT) algorithm should determine the global peak power point avoiding the PV system getting trapped in local peak that gives considerable power loss. This paper proposes a novel fuzzy logic based tracking algorithm to determine global peak point in grid connected PV system under partially shaded condition. The proposed algorithm can track the maximum power point under normal as well as partial shading condition. The algorithm gives fast convergence and very low oscillation around the MPP with less complexity. The simulation results validate the performance and stability of the grid connected PV system using the proposed algorithm. [ABSTRACT FROM PUBLISHER]

A photovoltaic system connected to the grid is constituted by two main parts: a solar cell and a power converter DC-AC. The impedance adaptation between the two parties is a technological problem that essentially means the transfer of maximum power of PV generator to the grid. In this paper, a new technique for nonlinear control of power converter DC-AC is presented. This converter is built on two stages: a DC-DC stage and a DC-AC stage. The two blocks are bound by a DC voltage intermediate bus. The control objective is threefold: i) control the input voltage of the converter to find the MPP (maximum power point), ii) regulating the DC bus voltage, iii) generate a sinusoidal current at industrial frequency that will be injected into the network with a power factor near unity. The synthesis of controllers was performed using the technique of backstepping nonlinear control. A detailed analysis of the stability control system is presented. The performance of controllers has been validated by numerical simulation in MATLAB / SIMULINK. [ABSTRACT FROM PUBLISHER]