An inverter using buck-boost type chopper circuits for popular small-scale photovoltaic power system[edit | edit source]
Kasa, N.; Iida, T.; Iwamoto, Hideo, "An inverter using buck-boost type chopper circuits for popular small-scale photovoltaic power system," Industrial Electronics Society, 1999. IECON '99 Proceedings. The 25th Annual Conference of the IEEE , vol.1, no., pp.185,190 vol.1, 1999 doi: 10.1109/IECON.1999.822194
- This paper presents a newly developed transformer-less single phase inverter for a photovoltaic (PV) power system. The proposed system consists of two sets of a PV array and buck-boost type chopper circuit. However, it is afraid that the system has lower "using rate" of PV energy than that of the ordinary PV system, as each PV array is only operated in the half duration of the AC power frequency. In this paper, it is also discussed how to increase this "using rate" by varying the connected capacitor between PV array terminals. The perturbation and observation method is adapted to the maximum power tracking in our PV systems. We adopt the wavelet transform to detect a power outage. The experimental data shows that this new inverter can supply AC power to the utility grid line with the power factor nearly unity.
- In the proposed system the choppers are operated at a fixed frequency in discontinious current mode.
- Control is implemented using a perturbation and observation method based MPPT with an outage detection mode.
- THD is 6% at power output of 500W.
Life enhancer for SPV power systems [solar photovoltaics][edit | edit source]
Roy, D.P.; Gaffoor, S.A.; Avinash Kumar, C., "Life enhancer for SPV power systems [solar photovoltaics]," Industrial Technology 2000. Proceedings of IEEE International Conference on , vol.2, no., pp.258,260 vol.1, 19-22 Jan. 2000 doi: 10.1109/ICIT.2000.854145
- In this paper, the authors report the results of tests on small stand-alone solar photovoltaic (SPV) power systems. The systems were monitored regularly to determine the application specific effect on the systems with an emphasis on battery behavior. The performance of a life enhancer is extremely satisfactory.
- Paper discusses mainly the advantages of intelligent charge controller unit (ICCU).
- Without life enhancer the capacity of batteries dropped from 110-112% to 84-86%. With the implementation of life enhancer the capacity dropped only to 100-106%.
The reliability assessment of central photovoltaic inverter in electric power system[edit | edit source]
Alferidi, A.; Mohamed, Y.A.-R.I., "The reliability assessment of central photovoltaic inverter in electric power system," Photovoltaic Specialist Conference (PVSC), 2014 IEEE 40th , vol., no., pp.3156,3161, 8-13 June 2014 doi: 10.1109/PVSC.2014.6925605
- The electric power system produced by Photovoltaic (PV) system is being gradually utilized in power system network with different Photovoltaic configuration. The central Photovoltaic inverter system is designed in large scale of solar power. This system has a different impact on system reliability than conventional generation due the intermittent nature of geographical locations and the availability of PV electronic system. It is therefore vital to evaluate the reliability contribution of central PV system in electric power system network taken into account entire PV system components. This project uses a probabilistic and Part-Count approach to develop the output power of central PV system. A developed model is then applied to Small Isolated Power System (SIPS) to study the system adequacy and the capacity credit of installing Photovoltaic units.
- Paper discusses the reliability contribution process of a central PV system in a small isolated power system.
- Addition of PV systems to a small grid increases overall system reliability.
- Addition of PV system increases the incremental peak load carrying capacity(IPLCC) of the power system.
Understanding of defect physics in polycrystalline photovoltaic materials[edit | edit source]
Yan, Yanfa, "Understanding of defect physics in polycrystalline photovoltaic materials," Photovoltaic Specialists Conference (PVSC), 2011 37th IEEE , vol., no., pp.001218,001222, 19-24 June 2011 doi: 10.1109/PVSC.2011.6186177
- The performance of thin-film solar cells is influenced by the quality of interfaces and formation of defects such as point defects, stacking faults, twins, dislocations, and grain boundaries. It is important to understand the defect physics so that appropriate methods may be developed to suppress the formation of harmful defects. Here, we review our understanding of defect physics in thin-film photovoltaic (PV) materials such as Si, CdTe, Cu(In, Ga)Se2 (CIGS), Cu2ZnSnSe2 (CZTSe), and Cu2ZnSnS2 (CZTS) using the combination of nanoscale electron microscopy characterization and density-functional theory (DFT). Although these thin-film PV materials share the same basic structural feature - diamond structure based - the defect physics in them could be very different. Some defects, such as stacking faults and special twins, have similar electronic properties in these thin-film materials. However, some other defects, such as grain boundaries and interfaces, have very different electronic properties in these materials. For example, grain boundaries produce harmful deep levels in Si and CdTe, but they do not produce significant deep levels in CIGS, CZTSe, and CZTS. These explain why passivation is critical for Si and CdTe solar cells, but is less important in CIS and CZTS solar cells. We further provide understanding of the effects of interfaces on the performance of solar cells made of these PV materials.
- Defect physics on thin film PV materials such as Si, CdTe, CIGS, etc have been analysed.
- A defect can exhibit different behaviour in terms of electronic properties in different materials.
- Defects should me minimized so as to optimize cell performance.
The Stand-alone PV Generation System with Parallel Battery Charger[edit | edit source]
Hong Wang; Donglai Zhang, "The Stand-alone PV Generation System with Parallel Battery Charger," Electrical and Control Engineering (ICECE), 2010 International Conference on , vol., no., pp.4450,4453, 25-27 June 2010 doi: 10.1109/iCECE.2010.1083
- The energy storage devices are necessary to the stand alone PV generation system. Lead acid battery which performance is specially designed is suitable for PV generation application. The battery charging and discharging control with the max power of PV array is the key point to increase efficiency of the generation system. In this paper, the new system configuration with parallel battery charger is designed. The conversion steps are decreased and system conversion efficiency is increased. The two module MPPT coordinate control is designed to increase PV utilizing efficiency. According to the different battery characteristics, the battery management is optimized for better performance and longer life time. The performance and total efficiency of PV generating system can be improved for stand-alone application. The experimental results of the prototype verify the effectiveness of proposed protocol and strategy.
- Commonly used battery - Gel type lead acid battery.
- Objective - Extend battery operating lifetime.
- System design, MPPT control algorithm are discussed.
- Parallel system - Individual converters supplying DC bus and battery charger.
- System energy is balanced between total generation and total demand.
- Implemented system is multifunctional operating as MPPT, battery charger, battery regulator and inverter.
A current and future state of art development of hybrid energy system using wind and PV-solar[edit | edit source]
Pragya Nema, R.K. Nema, Saroj Rangnekar," A current and future state of art development of hybrid energy system using wind and PV-solar": A review, Renewable and Sustainable Energy Reviews, Volume 13, Issue 8, October 2009, Pages 2096-2103, ISSN 1364-0321 (http://www.sciencedirect.com/science/article/pii/S1364032108001755)
- The wind and solar energy are omnipresent, freely available, and environmental friendly. The wind energy systems may not be technically viable at all sites because of low wind speeds and being more unpredictable than solar energy. The combined utilization of these renewable energy sources are therefore becoming increasingly attractive and are being widely used as alternative of oil-produced energy. Economic aspects of these renewable energy technologies are sufficiently promising to include them for rising power generation capability in developing countries. A renewable hybrid energy system consists of two or more energy sources, a power conditioning equipment, a controller and an optional energy storage system. These hybrid energy systems are becoming popular in remote area power generation applications due to advancements in renewable energy technologies and substantial rise in prices of petroleum products. Research and development efforts in solar, wind, and other renewable energy technologies are required to continue for, improving their performance, establishing techniques for accurately predicting their output and reliably integrating them with other conventional generating sources. The aim of this paper is to review the current state of the design, operation and control requirement of the stand-alone PV solar–wind hybrid energy systems with conventional backup source i.e. diesel or grid. This Paper also highlights the future developments, which have the potential to increase the economic attractiveness of such systems and their acceptance by the user.
- Advances in power electronic semiconductor devices have lead to improved efficiency, system quality and reliability.
- Though cost reduction and technological developments have been encouraging it is still an expensive power source.
- Combining solar PV with wind energy can significantly reduce economical burden.
Hybrid PV/T solar systems for domestic hot water and electricity production[edit | edit source]
S.A. Kalogirou, Y. Tripanagnostopoulos, Hybrid PV/T solar systems for domestic hot water and electricity production, Energy Conversion and Management, Volume 47, Issues 18–19, November 2006, Pages 3368-3382, ISSN 0196-8904 (http://www.sciencedirect.com/science/article/pii/S0196890406000409)
- Hybrid photovoltaic/thermal (PV/T) solar systems can simultaneously provide electricity and heat, achieving a higher conversion rate of the absorbed solar radiation than standard PV modules. When properly designed, PV/T systems can extract heat from PV modules, heating water or air to reduce the operating temperature of the PV modules and keep the electrical efficiency at a sufficient level. In this paper, we present TRNSYS simulation results for hybrid PV/T solar systems for domestic hot water applications both passive (thermosyphonic) and active. Prototype models made from polycrystalline silicon (pc-Si) and amorphous silicon (a-Si) PV module types combined with water heat extraction units were tested with respect to their electrical and thermal efficiencies, and their performance characteristics were evaluated. The TRNSYS simulation results are based on these PV/T systems and were performed for three locations at different latitudes, Nicosia (35°), Athens (38°) and Madison (43°). In this study, we considered a domestic thermosyphonic system and a larger active system suitable for a block of flats or for small office buildings. The results show that a considerable amount of thermal and electrical energy is produced by the PV/T systems, and the economic viability of the systems is improved. Thus, the PVs have better chances of success especially when both electricity and hot water is required as in domestic applications.
- As the ambient temperature increases, there is a drop in the efficiency of the PV module.
- This undesirable effect can be reduced by heat extraction via fluid circulation.
- This can be coupled with a thermal solar unit for heating water for domestic purposes.
- Subsidies are required to draw people towards such systems due to high initial costs.
A stand-alone photovoltaic supercapacitor battery hybrid energy storage system[edit | edit source]
Glavin, M.E.; Chan, P.K.W.; Armstrong, S.; Hurley, W.G., "A stand-alone photovoltaic supercapacitor battery hybrid energy storage system," Power Electronics and Motion Control Conference, 2008. EPE-PEMC 2008. 13th , vol., no., pp.1688,1695, 1-3 Sept. 2008 doi: 10.1109/EPEPEMC.2008.4635510 http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4635510&isnumber=4635237
- Most of the stand-alone photovoltaic (PV) systems require an energy storage buffer to supply continuous energy to the load when there is inadequate solar irradiation. Typically, Valve Regulated Lead Acid (VRLA) batteries are utilized for this application. However, supplying a large burst of current, such as motor startup, from the battery degrades battery plates, resulting in destruction of the battery. An alterative way of supplying large bursts of current is to combine VRLA batteries and supercapacitors to form a hybrid storage system, where the battery can supply continuous energy and the supercapacitor can supply the instant power to the load. In this paper, the role of the supercapacitor in a PV energy control unit (ECU) is investigated by using Matlab/Simulink models. The ECU monitors and optimizes the power flow from the PV to the battery-supercapacitor hybrid and the load. Three different load conditions are studied, including a peak current load, pulsating current load and a constant current load. The simulation results show that the hybrid storage system can achieve higher specific power than the battery storage system.
- By utilizing a supercapacitor in conjunction with a battery, its size can be reduced and higher SOC can be maintained.
- An Energy control Unit (ECU) has been developed to manage power flow between PV module, battery,ultracapacitor and load.
- Simulation results show that the battery SOC is higher than conventional operation and also the battery life is increased.
Stand-alone photovoltaic energy storage system with maximum power point tracking[edit | edit source]
Pacheco, V.A.; Freitas, L.C.; Vieira, J.B.; Coelho, E.A.A.; Farias, V.J., "Stand-alone photovoltaic energy storage system with maximum power point tracking," Applied Power Electronics Conference and Exposition, 2003. APEC '03. Eighteenth Annual IEEE , vol.1, no., pp.97,102 vol.1, 9-13 Feb. 2003 doi: 10.1109/APEC.2003.1179182
- This digests deals with the study of a stand-alone photovoltaic system, which is able to extract the maximum power from photovoltaic array for all solar intensity conditions and to provide output voltage regulation. The proposed system consists of a DC-DC converter in combination with battery energy storage in a simple structure. Operating principle and control strategy are described. Digital simulation is included, supporting the validity of the concept.
- PV system with two converters: an input boost converter for voltage regulation and a bi-directional converter for battery charge and to step-up battery voltage to output DC bus.
- Mode 1 - battery charge.
- Mode 2 - Energy compensation.
- Control strategy modelled on non-linear dynamics theory.
Combined low-cost, high-efficient inverter, peak power tracker and regulator for PV applications[edit | edit source]
J. H. R. Enslin and D. B. Snyman, "Combined low-cost, high-efficient inverter, peak power tracker and regulator for PV applications," IEEE Transactions on Power Electronics, vol. 6, no. 1, pp. 73–82, Jan. 1991.
- A novel compound power converter that serves as a DC-to-AC inverter, maximum power point tracker (MPPT), and battery charger for stand-alone photovoltaic (PV) power systems is introduced. A theoretical analysis of the proposed converter is performed, and the results are compared with experimental results obtained from a 1.5 kW prototype. The overall cost of PV systems can thus be reduced by using load management control and efficiency-optimization techniques. Power flow through the converter is controlled by means of a combination of duty cycle and output frequency control. With load management, large domestic loads, such as single phase induction motors for water pumping, hold-over refrigerators, and freezers, can be driven by day at a much higher energy efficiency. This is due to the high efficiency of the inverter with high insolation, and because the inverter uses the energy directly from the solar array. The battery loss component is thus reduced
Silicon-on-ceramic for low cost solar cells[edit | edit source]
Zook, J.D.; Maciolek, R.B.; Heaps, J.D., "Silicon-on-ceramic for low cost solar cells," Electron Devices Meeting, 1977 International , vol.23, no., pp.218,221, 1977 doi: 10.1109/IEDM.1977.189211
- Inexpensive ceramic substrates can be coated from the melt with a thin layer of large grain polycrystalline silicon to produce low cost solar cells. The properties are quite similar to those of EFG ribbons. A focussed light beam from a monochromator was used to evaluate cell uniformity and to measure minority carrier diffusion length within grains. Cells with active areas of 1cm2and without AR coatings currently have AM1 conversion efficiencies over 7% and inherent efficiencies over 12%.
Residential photovoltaic energy storage system[edit | edit source]
Chiang, S.J.; Chang, K.T.; Yen, C.Y., "Residential photovoltaic energy storage system," Industrial Electronics, IEEE Transactions on , vol.45, no.3, pp.385,394, Jun 1998 doi: 10.1109/41.678996
- This paper introduces a residential photovoltaic (PV) energy storage system, in which the PV power is controlled by a DC-DC power converter and transferred to a small battery energy storage system (BESS). For managing the power, a pattern of daily operation considering the load characteristic of the homeowner, the generation characteristic of the PV power, and the power-leveling demand of the electric utility is prescribed. The system looks up the pattern to select the operation mode, so that powers from the PV array, the batteries and the utility are utilized in a cost-effective manner. As for the control of the system, a novel control technique for the maximum power-point tracking (MPPT) of the PV array is proposed, in which the state-averaged model of the DC-DC power converter, including the dynamic model of the PV array, is derived. Accordingly, a high-performance discrete MPPT controller that tracks the maximum power point with zero-slope regulation and current-mode control is presented. With proposed arrangements on the control of the BESS and the current-to-power scaling factor setting, the DC-DC power converter is capable of combining with the BESS for performing the functions of power conditioning and active power filtering. An experimental 600 W system is implemented, and some simulation and experimental results are provided to demonstrate the effectiveness of the proposed system.
- System consists of a bi-directional converter connecting the PV array, battery, load and utility.
- The PV control section employs multi-loop control with the inductor current of boost converter in inner loop for achieving fast dynamic response.
- A prototype 600W system was implemented, with reasonable degree of reliability and efficient operation.
A study of maximum power point tracking algorithms for stand-alone Photovoltaic Systems[edit | edit source]
Mei Shan Ngan; Chee Wei Tan, "A study of maximum power point tracking algorithms for stand-alone Photovoltaic Systems," Applied Power Electronics Colloquium (IAPEC), 2011 IEEE , vol., no., pp.22,27, 18-19 April 2011 doi: 10.1109/IAPEC.2011.5779863
- The Photovoltaic (PV) energy is one of the renewable energies that attracts attention of researchers in the recent decades. Since the conversion efficiency of PV arrays is very low, it requires maximum power point tracking (MPPT) control techniques to extract the maximum available power from PV arrays. In this paper, two categories of MPPT algorithms, namely indirect and direct methods are discussed. In addition to that, the advantages and disadvantages of each MPPT algorithm are reviewed. Simulations of PV modules were also performed using Perturb and Observe algorithm and Fuzzy Logic controller. The simulation results produced by the two algorithms are compared with the expected results generated by Solarex MSX60 PV modules. Besides that, the P-V characteristics of PV arrays under partial shaded conditions are discussed in the last section.
- The following methods have been discussed
- Perturb and observe (P&O) method.
- Incremental conductance method.
- Open circuit voltage method.
- Short circuit current method.
- Fuzzy logic controller.
Photovoltaic converter system suitable for use in small scale stand-alone or grid connected applications[edit | edit source]
Gow, J.A.; Manning, C.D., "Photovoltaic converter system suitable for use in small scale stand-alone or grid connected applications," Electric Power Applications, IEE Proceedings - , vol.147, no.6, pp.535,543, Nov 2000 doi: 10.1049/ip-epa:20000789
- Of the commercially-available solutions for the conversion of energy from photovoltaic arrays into a usable form, a large number consist of systems which
have been developed for a dedicated application and are thus very inflexible. Those that are available as a generic module for use in a variety of environments are often restricted to a single mode of operation, for example utility supply only. A generic modular photovoltaic power conversion system is presented, aimed at single-phase applications which can supply passive AC and DC loads with a regulated voltage or by way of a maximum power tracking system with the maximum power available from the array. In addition a live AC load such as the utility can be supplied with maximum array power. The system is small, light and can be constructed from readily available components
- Voltage mode boost controller is applied to boost converter
- Slightly more complicated control is the average average current mode control.
- Prototype PV controller system was implemented for use upto 1Kw.
- The control implemented has fast dynamic response with high stability.
Low-cost solar cells based on large-area unconventional silicon[edit | edit source]
Fischer, H.; Pschunder, W., "Low-cost solar cells based on large-area unconventional silicon," Electron Devices, IEEE Transactions on , vol.24, no.4, pp.438,442, Apr 1977 doi: 10.1109/T-ED.1977.18753
- Low-cost approaches to solar cell manufacture require the use of inexpensive low-grade nonsingle crystalline silicon. Earlier experimental results indicate that conventional polysilicon, as it is used as ingot for the single crystal growing process, leads to solar cells of poor photovoltaic performance. These problems were overcome by utilizing unconventional nonsingle crystalline silicon, which is characterized by controlled size and structure of the individual grains. With modified processing, optimized in respect to the unique structure of the material, large-area solar cells could be realized under production scheme methods. Cells exhibiting dimensions up to 11 cm × 11 cm were fabricated, AM0 efficiencies of 8 percent could be achieved corresponding to AM1 values exceeding 10 percent. On test samples of 2 cm × 2 cm area AM0 efficiency Of 12.5 percent (AM1 value equivalent 14.0 percent) could be reached. The new material together with the optimized processes offer potentials for significant cost reduction by virtue of their being applicable to volume production and to automated fabrication techniques.
Synchronous Buck Converter based PV Energy System for Portable Applications[edit | edit source]
B. ChittiBabu, S. R. Samantaray, N. Saraogi, M. V. Ashwin Kumar, R. Sriharsha, and S. Karmaker, "Synchronous Buck Converter based PV Energy System for Portable Applications," in 2011 IEEE Students' Technology Symposium (TechSym), 2011, pp. 335–340.
- Synchronous buck converter based photo voltaic (PV) energy system for portable applications is presented in this paper; especially to charge the batteries used in mobile phones. The main advantage of using synchronous buck converter is to reduce the switching loss in the main MOSFET over conventional dc-dc buck converter. The switching loss is minimized by applying soft switching techniques such as zero-voltage switching (ZVS) and zero-current switching (ZCS) in the proposed converter. Thus the cost effective solution is obtained; especially in the design of heat sink in the dc-dc converter circuit. The DC power extracted from the PV energy system is synthesized and modulated through synchronous buck converter in order to suit the load requirements. The characteristic of PV array is studied under different values of temperature and solar irradiation. Further, the performance of such converter is analyzed and compared with classical dc-dc buck converter in terms of switching loss reduction and improved converter efficiency. The whole system is studied in the MATLAB-Simulink environment.
Generation control circuit for photovoltaic modules[edit | edit source]
Shimizu, T.; Hirakata, M.; Kamezawa, T.; Watanabe, H., "Generation control circuit for photovoltaic modules," Power Electronics, IEEE Transactions on , vol.16, no.3, pp.293,300, May 2001 doi: 10.1109/63.923760
- Photovoltaic modules must generally be connected in series in order to produce the voltage required to efficiently drive an inverter. However, if even a very small part of photovoltaic module (PV module) is prevented from receiving light, the generation power of the PV module is decreased disproportionately. This greater than expected decrease occurs because PV modules which do not receive adequate light cannot operate on the normal operating point, but rather operate as loads. As a result, the total power from the PV modules is decreased if even only a small part of the PV modules are shaded. In the present paper, a novel circuit, referred to as the generation control circuit (GCC), which enables maximum power to be obtained from all of the PV modules even if some of the modules are prevented from receiving light. The proposed circuit enables the individual PV modules to operate effectively at the maximum power point tracking, irrespective of the series connected PV module system. In addition, the total generated power is shown experimentally to increase for the experimental set-up used in the present study.
- Paper discusses connection methods of PV modules and related problems that arise due to each configuration.
- Two circuit configurations are discussed, DC-DC converter type and a multi-stage chopper type.
- Simulation results indicate satisfactory working of the two configurations, with the multi - stage chopper system being more advantageous.
A simple PV array modeling using MATLAB[edit | edit source]
Bhaskar, M.A.; Vidya, B.; Madhumitha, R.; Priyadharcini, S.; Jayanthi, K.; Malarkodi, G.R., "A simple PV array modeling using MATLAB," Emerging Trends in Electrical and Computer Technology (ICETECT), 2011 International Conference on , vol., no., pp.122,126, 23-24 March 2011 doi: 10.1109/ICETECT.2011.5760103
- This paper presents the general overview on the requirement of renewable energy mainly the solar power. We have also dealt with the types of solar power available and the basic modeling of solar energy system mainly the photo voltaic type has been discussed. MATLAB Simulink has been used as a tool to provide the I-V and P-V plots of the system.
- Paper discusses the mathematical modelling of a PV array in MATLAB.
- 4 PV modules of rating 16 - 25 V have been modelled.
- The V-I and P-V characteristics have been plotted.
Modeling and Simulation of Photovoltaic module using MATLAB/Simulink[edit | edit source]
Mohammed, S. Sheik. "Modeling and Simulation of Photovoltaic module using MATLAB/Simulink." International Journal of Chemical and Environmental Engineering 2.5 (2011).
- This paper presents modeling of Photovoltaic (PV) module using MATLAB/Simulink. The model is developed based on the mathematical model of the PV module. Two particular PV modules are selected for the analysis of developed model. The essential parameters required for modeling the system are taken from datasheets. I-V and P-V characteristics curves are obtained for the selected modules with the output power of 60W and 64W from simulation and compared with the curves provided by the datasheet. The results obtained from the simulation model are well matched with the datasheet information.*Mathematical modelling of PV cell is performed.
- Essential input parameters are taken frommanufacture data sheets.
- Models are simulated and results are compared to manufacturer data sheets.
