Grid connected fuel cell and PV hybrid power generating system design with Matlab Simulink

Renewable energy sources have been taken the place of the traditional energy sources and especially rapidly developments of photovoltaic (PV) technology and fuel cell (FC) technology have been put forward these renewable energy sources (RES) in all other RES. PV systems have been started to be used widely in domestic applications connected to electrical grid and grid connected PV power generating systems have become widespread all around the world. On the other hand, fuel cell power generating systems have been used to support the PV generating so hybrid generation systems consist of PV and fuel cell technology are investigated for power generating. In this study, a grid connected fuel cell and PV hybrid power generating system was developed with Matlab Simulink. 160 Wp solar module was developed based on solar module temperature and solar irradiation by using real data sheet of a commercial PV module and then by using these modules 800 Wp PV generator was obtained. Output current and voltage of PV system was used for input of DC/DC boost converter and its output was used for the input of the inverter. PV system was connected to the grid and designed 5 kW solid oxide fuel cell (SOFC) system was used for supporting the DC bus of the hybrid power generating system. All results obtained from the simulated hybrid power system were explained in the paper. Proposed model was designed as modular so designing and simulating grid connected SOFC and PV systems can be developed easily thanks to flexible design.     

Residential PV system users' perception of profitability,reliability, and failure risk: An empirical survey in a local Japanese municipality

Although previous studies have addressed the reliability of residential PV systems in order to improve the dissemination of the systems among individual users and societies, few have examined users' perception of their own PV systems, which might contain solutions to firmly establish the system into society. First, the present paper examined the extent to which residential PV system users understand specification, reliability, and failure risk of their own systems. Second, causal factors affecting users' satisfaction with PV systems were examined. By analyzing data collected in Kakegawa City, this paper revealed that users did not appropriately understand the basic specifications of their residential PV systems, and in particular, the fact that the systems sometimes failed and therefore needed proper maintenance. Furthermore, a strong causal relationship between users' expectations of financial return from the system and their level of satisfaction was confirmed empirically. These results suggested that excessive focus on profitability and relatively low interest in the systems' reliability and failure risk should be addressed more to avoid problems that could potentially hamper the establishment of this technology into society.     

Operation strategy of residential centralized photovoltaic system in remote areas

Photovoltaic (PV) systems have found fairly wide application in remote isolated area. However, each individual PV system usually supplies energy only to one consumer. In such a case we have several consumers that each one of them uses a stand-alone PV system. This situation would expose such stand-alone systems to transient excessive loads larger than the power generated by the PVs, and then the battery is bound to discharge even during the day. For overcoming this problem, we suggest an autonomous centralized PV system, comprising one battery bank and plural subsystems connected to each other. From solar radiation data and load profiles, the performance of the PV centralized system is simulated by using a time step scheme. The advantages of this system are found to be the large charging rate of power, high efficiency, and low cost compared with conventional individual PV systems and hybrid systems. In addition, the economic study shows that the life cycle cost and the price of kilowatt hour generated in the centralized system is lower than that for the individual systems.     

Reliability evaluation of future photovoltaic systems with smart operation strategy

This paper investigates a new operation strategy for photovoltaic (PV) systems, which improves the overall reliability of the system as a result of the improvement in the reliability of the critical components. First, a mathematical model is proposed using the fault tree analysis (FTA) to estimate the reliability of the PV systems in order to find the suitable maintenance strategies. The implementations demonstrate that it is essential to employ smart maintenance plans and monitor the identified most critical components of PV systems. Then, an innovative analytical method based on the Markov process is presented to model smart operation plans in PV systems. The impact of smart operation strategy on the PV systems is then evaluated. The objective of this paper is to develop plans for improving the reliability of PV systems. A series of case studies have been conducted to demonstrate the importance of smart operation strategies for PV systems as well as the applicability and feasibility of the proposed method.     

Modeling and simulation of grid-connected photovoltaic energy conversion systems

Solar power generation using PV (photovoltaic) technology is a key but still evolving technology with the fastest growing renewable-based market worldwide in the last decade. In this sector with tremendous potential for energy security and economic development, grid-connected PV systems are becoming today the most important application of solar PV generation. Based on this trend, PV system designers require an accurate and reliable tool in order to predict the dynamic performance of grid-tied PV systems at any operating conditions. This will allow evaluating the impact of PV generation on the electricity grids. This paper presents a detailed characterization of the performance and dynamic behavior of a grid-connected PV energy conversion system. To this aim, a flexible and accurate PV simulation and evaluation tool (called PVSET 1.0) is developed. The PV system is modeled, simulated and validated under the MATLAB/Simulink environment. The accuracy of simulation results has been verified using a 250 Wp PV experimental set-up.     

Control and real time monitoring of less battery storage photovoltaic plants

Control, sizing and management of stand-alone or grid-connected photovoltaic (PV) plants are based on static methods, energy estimation and simulations of the PV systems in average conditions. Despite the fact that these approaches provide information about the expected performances, they do not perform an optimization of the PV plant; nor do they allow an optimal matching of PV-load association for the local climate conditions. Besides that, the problems of the PV cost, the maintenance and the battery replacements remain an obstacle for the development of PV plants.

To surmount these problems (storage, control, cost and efficiency), we have developed in our laboratory new prototypes of less battery storage systems (LBSS), which substitute the battery storage by a thermal storage for PV refrigeration or a hydraulic storage for PV pumping and water desalination (Cherif, A. (1994). Optimization and management of new PV refrigeration plant using latent storage. In Proceedings of the 12th E.P.S.E. Conference, Amsterdam, Vol. 1, HS Stephens & Associates, pp. 448–452). This approach will contribute to reduce the maintenance operations, the PV cost and the breakdowns of the battery and its regulator. We have introduced a new control strategy based on the performance of the DC/DC and DC/AC converters and the real time monitoring of the PV plant. This paper presents the technical and experimental aspects of these LBSS systems.     

Rural photovoltaic electrification program in Jordan

The photovoltaic (PV) technology potential for Jordan is high, based on the fact that many remote and isolated sites are located far away from the national electric grid and cannot be connected to it in the near future. Therefore, a rural PV electrification program—driven by quality-of-life improvement for the users—was launched in Jordan in 2002. An important element of the program is the access of low-income, rural consumers to essential electricity.This paper discusses and analyses the first stage of this program that is the electrification of a remote and small Jordanian village. Nine PV solar home systems (SHS) were installed in this village in order to provide lighting and power for radio and television.Feed back from the users of the installed systems indicates that the PV based electricity has been providing very satisfactory service to the consumers, and that it is an appropriate technology suitable for dissemination in the rural Jordanian areas.     

Measurements, analyses and evaluation of residential PV systems by Japanese monitoring program

This paper is about measurements, analyses and evaluation of residential PV systems in the Japanese Monitoring Program, on which JQA was subsidized by NEDO (New Energy Development and Industrial Technology Organization) that is currently proceeding [NSS R&D] from FY1997 to FY 2000.The aim of this investigation refers, through the data evaluation and analyses, to obtain knowledge required for optimizing design of PV systems, such as system performance, characteristics and regional dependency under practical operation and to develop the system evaluation technology on the design parameter method.     

A voltage regulation method for dispersed grid-connected PV systems under high-density connection

This paper describes a voltage regulation method for dispersed grid-connected PV systems under high-density connection. In the near future, many PV systems will be connected to distribution systems. The reverse power flow of the grid-connected PV systems will raise line voltage to the upper limit of the legal voltage range. In the first part of this paper we examine the voltage characteristics of a distribution system under high-density connection, while the second part of the paper describes a voltage regulation method for high-density PV connections, using reactive power proportional to global irradiance. The results of tests clearly demonstrate a restraining effect on voltage during the daytime and a smoothing effect on voltage fluctuation.     

Improved parametric empirical determination of module short circuit current for modelling and optimization of solar photovoltaic systems

Correct modelling of solar photovoltaic (PV) system yields is necessary to optimize system design, improve reliability of projected outputs to ensure favourable project financing and to facilitate proper operations and maintenance. An improved methodology for fine resolution modelling of PV systems is presented using module short-circuit current (I_sc) at 5-min time-scales, and clearly identifies pertinent error mechanisms that arise when working at this high resolution. This work used a modified version of the Sandia array performance model, and introduces new factors to the calculation of I_sc to account for identified error mechanisms, including instrumentation alignment, spectral, and module power tolerance errors. A simple methodology was introduced and verified where specific module parameters can be derived solely from properly filtered performance time series data. In particular, this paper focused on methodologies for determining the predicted I_sc for a variety of solar PV module types. These methods of regressive analysis significantly reduced the error of the predicted model, and demonstrate the need for this form of modelling when evaluating long term PV array performance. This methodology has applications for current systems operators, which will enable the extraction of useful module parameters from existing data in addition to more precise continuous monitoring of existing systems, and can also be used to more accurately model and optimize new systems.     

Study on control method of the stand-alone direct-coupling photovoltaic – Water electrolyzer

Based on photovoltaic as an energy resource and hydrogen as an energy carrier, we propose control methods of a photovoltaic-water electrolyzer (PV-WE) system that efficiently generates hydrogen by controlling the number of WE cells. The advantage of this direct coupling between PV and WE is that the power loss due to the DC/DC converter is avoided. Here, several different methods to control the number of WE cells in a stand-alone PV-WE system that is isolated from the electrical grid according to the weather condition were investigated: IV estimation method, PV module temperature method and PV current method. In the IV estimation method, first the current–voltage (IV) characteristics of the PV are calculated based on the measured solar insolation and PV module temperature, and then the nonlinear equation of the IV characteristics of the PV is solved to determine the optimum number of WE cells. In the PV module temperature method, only the PV module temperature and PV output current are used for control. In the PV current method, only the PV output current is used, and thus this method is the easiest among these methods to actually implement. Neither the PV module temperature method nor the PV current method requires solving any nonlinear equation of the IV characteristics of the PV. Each of these three control methods experimentally achieved a high maximum power point tracking efficiency (MPPT efficiency = actual PV output/maximum PV output), which was 98% or higher. Furthermore, to compare each control method, simulations of the PV-WE system were carried out using measured insulation and PV module temperature data for a 1-year period. Each of these three control methods also achieved a high MPPT efficiency in the annual simulations.     

Review of R&D progress and practical application of the solar photovoltaic/thermal (PV/T) technologies

In this paper, the global market potential of solar thermal, photovoltaic (PV) and combined photovoltaic/thermal (PV/T) technologies in current time and near future was discussed. The concept of the PV/T and the theory behind the PV/T operation were briefly introduced, and standards for evaluating technical, economic and environmental performance of the PV/T systems were addressed. A comprehensive literature review into R&D works and practical application of the PV/T technology was illustrated and the review results were critically analysed in terms of PV/T type and research methodology used. The major features, current status, research focuses and existing difficulties/barriers related to the various types of PV/T were identified. The research methods, including theoretical analyses and computer simulation, experimental and combined experimental/theoretical investigation, demonstration and feasibility study, as well as economic and environmental analyses, applied into the PV/T technology were individually discussed, and the achievement and problems remaining in each research method category were described. Finally, opportunities for further work to carry on PV/T study were identified. The review research indicated that air/water-based PV/T systems are the commonly used technologies but their thermal removal effectiveness is lower. Refrigerant/heat-pipe-based PV/Ts, although still in research/laboratory stage, could achieve much higher solar conversion efficiencies over the air/water-based systems. However, these systems were found a few technical challenges in practice which require further resolutions. The review research suggested that further works could be undertaken to (1) develop new feasible, economic and energy efficient PV/T systems; (2) optimise the structural/geometrical configurations of the existing PV/T systems; (3) study long term dynamic performance of the PV/T systems; (4) demonstrate the PV/T systems in real buildings and conduct the feasibility study; and (5) carry on advanced economic and environmental analyses. This review research helps finding the questions remaining in PV/T technology, identify new research topics/directions to further improve the performance of the PV/T, remove the barriers in PV/T practical application, establish the standards/regulations related to PV/T design and installation, and promote its market penetration throughout the world.     

Computer-aided design of PV/wind hybrid system

A complete set of match calculation methods for optimum sizing of PV/wind hybrid system is presented. In this method, the more accurate and practical mathematic models for characterizing PV module, wind generator and battery are adopted; combining with hourly measured meteorologic data and load data, the performance of a PV/wind hybrid system is determined on a hourly basis; by fixing the capacity of wind generators, the whole year’s LPSP (loss of power supply probability) values of PV/wind hybrid systems with different capacity of PV array and battery bank are calculated, then the trade-off curve between battery bank and PV array capacity is drawn for the given LPSP value; the optimum configuration which can meet the energy demand with the minimum cost can be found by drawing a tangent to the trade-off curve with the slope representing the relationship between cost of PV module and that of the battery. According to this match calculation method, a set of match calculation programs for optimum sizing of PV/wind hybrid systems have been developed. Applying these match calculation programs to an assumed PV/wind hybrid system to be installed at Waglan island of Hong Kong, the optimum configuration and its hourly, daily, monthly and yearly performances are given.     

Grid matching of large-scale wind energy conversion systems,alone and in tandem with large-scale photovoltaic systems: An Israeli case study

This paper presents a grid matching analysis of wind energy conversion systems (WECSs) and photovoltaic (PV)–WECS hybrid systems. The study was carried out using hourly load data of the Israel Electric Corporation (IEC) for the year 2006 and the corresponding simulated hourly performance of large PV and WECS plants in the Negev Desert. Our major objective was to compare the grid-matching capabilities of wind with those of our previously published PV results, and to assess the extent to which the combined employment of WECS and PV can improve the grid matching capability of either technology when used on its own. We find that, due to the differences in diurnal and seasonal output profiles of WECS and PV, their tandem employment significantly improves grid penetration compared to their use individually.     

Performance results and analysis of 3 kW grid-connected PV systems

Four 3 kW grid-connected photovoltaic (PV) generation systems have been installed and monitored at the Field Demonstration Test Center in Korea since October 2002. To observe the overall effect of meteorological conditions on their operation characteristics by field test, the monitoring system has been constructed for measuring and analyzing the performance of PV systems and components in November 2002. In this paper, the performance of PV systems is evaluated and analyzed not only for component perspective but also for global perspective by reviewing one year of monitoring results and loss factors of PV systems. On the basis of these monitoring results, the performance of PV systems is compared to the measured performance of PV systems with the estimated performance by simulation. These results will indicate that it is highly imperative to develop evaluation, analysis and application technology for PV systems.     

Evaluation of operation characteristics in multiple interconnection of PV systems

A method for evaluating the operation characteristic of grid-connected PV systems in multiple interconnection was proposed and a suppression of PV electric energy which is reduced by an automatic voltage control unit was estimated using a yearly scale simulation. The automatic voltage control unit is one of the PV inverter functions. In Japan, PV systems must be provided with this function to maintain within 101 V±6 V for the standard voltage of 100 V according to the technical recommendations. The automatic control voltage unit adjusts the distribution-line voltage at a connected point using leading reactive power or active power. Especially, the adjustment of active power will cause a suppression of PV electric energy.     

Review of the performance of residential PV systems in France

The main objective of this paper is to review the state of the art of residential PV systems in France. This is done analyzing the operational data of 6868 installations. Three main questions are posed. How much energy do they produce? What level of performance is associated to their production? Which are the key parameters that most influence their quality? During the year 2010, the PV systems in France have produced a mean annual energy of 1163 kWh/kW_p. As a whole, the orientation of PV generators causes energy productions to be some 7% inferior to optimally oriented PV systems. The mean Performance Ratio is 76% and the mean Performance Index is 85%. That is to say, the energy produced by a typical PV system in France is 15% inferior to the energy produced by a very high quality PV system. On average, the real power of the PV modules falls 4.9% below its corresponding nominal power announced on the manufacturer's datasheet. A brief analysis by PV modules technology has led to relevant observations about two technologies in particular. On the one hand, the PV systems equipped with heterojunction with intrinsic thin layer (HIT) modules show performances higher than average. On the other hand, the systems equipped with the copper indium (di)selenide (CIS) modules show a real power that is 16% lower than their nominal value.     

太阳能光电/光热一体化技术及其应用进展研究

太阳能光电/光热一体化系统主要由光伏电池组件和太阳能集热器组成,可同时实现光伏发电和光热利用,从而有效地提高了太阳能的综合利用效率。文章首先从光伏组件和光热部件着手,分析了PV/T系统的结构和各项性能;然后,概述了目前常用的PV/T热水系统性能评估方法;最后,提出了在推广PV/T系统时还须解决的问题。     

Sensitivity analysis of PV output power to capacity configuration of energy storage systems from time and space characteristics

The acquisition granularity (time feature quantity) and sampling span (spatial feature quantity) of the data are the feature factors to analyze the active power of renewable energy power stations. According to the time and space characteristics of photovoltaic (PV) power stations, the acquisition granularity and sampling span calibration methods of PV output power based on data mining technology are proposed this paper. The initial range of the acquisition granularity is determined by analyzing the maximum‐order difference components of the PV output power. Through deeply mining the continuous change state of the PV output power, an acquisition granularity calibration method of the PV output power based on the multiobjective optimization model is proposed from time characteristics. The particle swarm optimization algorithm is used to solve the model to obtain the optimal the acquisition granularity of the PV power station. Through the analysis of the sample information entropy change trend of the PV output power, a sampling span calibration method of the PV output power based on the information entropy theory is proposed from space characteristics. The sensitivity analysis of the acquisition granularity and sampling span of the data to the capacity of energy storage systems is realized by the smooth control of the PV output power using first‐order low filters. The simulation tests of the annual history operating data at a PV power station with the installed capacity of 40 MW in China verify the validity of the provided methods. The simulation results show when the acquisition granularity takes 60 seconds and the sampling span takes 33 days, it can satisfy the accuracy of the required data of energy storage systems to realize the smooth control of the PV output power.     

Aquatic photovoltaic facility for Catalina Island

A feasibility study, design, and cost estimate have been completed for a 1 MWe photovoltaic (PV) facility which would float on an inland reservoir at Catalina Island. If built, this would be one of the largest PV operating facilities to date and also the first floating PV system. The modular installation consists of 250 floating platforms, each supporting 430 ft² of flat panel PV cells. Three tracking systems were considered; a two-axis tracking, a one-axis tracking, and a non-tracking system. The non-tracking and one-axis tracking systems were carried through the final design stage. The one-axis system was most cost effective. The total cost of the one-axis tracking system is about $4.0 million; the cost of the non-tracking system is about $3.7 million. The levelized energy costs for the two systems are about $0.37/kWh and $0.42/kWh respectively. This facility would provide 25% of Catalina's yearly peak energy demand; reducing the amount of diesel fuel used for power production. The aquatic environment provided difficult and unusual design criteria.