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Solar PV based open source water testing platform

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Open-pv.png This page is part of an MTU graduate course MY5490/EE5490: Solar Photovoltaic Science and Engineering. Both the course documentation and the course generated content is open source. However, the course runs over Spring semesters during this time it is not open edit. Please leave comments using the discussion tab.


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Contents

Literature Review[edit]

Optimal sizing of PV-battery for loss reduction and intermittency mitigation[edit]

Kalkhambkar, V.; Kumar, R.; Bhakar, R., "Optimal sizing of PV-battery for loss reduction and intermittency mitigation" Recent Advances and Innovations in Engineering (ICRAIE), 2014 , vol., no., pp.1,6, 9-11 May 2014 doi: 10.1109/ICRAIE.2014.6909297

Over these years, dependency of electric generation on renewables is increasing steadily. The renewable energy sources are usually connected to the electric grid on the distribution networks. Energy supply from prominent renewable sources like wind and solar are restricted due to the high level of unpredictability and intermittency associated with them. This leads to the inefficient and less reliable output from these sources. Thus proper generation prediction, sizing and intermittency mitigation of renewable energy sources such as wind and solar photovoltaic (PV) is necessary while placing them on the feeder. As these sources are distributed energy sources, the loss minimization can be one of the opportunities in addition to their generation support. This paper deals with the optimal sizing of solar PV and battery combination in a grid connected system. Solar PV generation is seen as the future generation source and battery storage with its matured technology can support it to become more reliable source in a power system. Here an analytical method for sizing of solar PV and battery is proposed. The line losses and intermittency minimization is the prime consideration for the sizing and placement of the solar PV and battery. To tackle with the variability of the solar PV generation, it is predicted by probability density function and supported by battery energy storage. The battery energy storage is properly sized to satisfy the state of charge limitations. The location and sizing methodology is applied to a 13-bus test system using MATLAB. With the proposed optimal sizing methodology the losses can be reduced up to 83 % during the solar PV generation period and a small amount of battery support can help to get constant power supply to the grid from the solar PV.
Notes:
  • The intermittency in solar radiation is accounted for by using a probability density factor.
  • The battery life is dependant on its SOC. The A-Hr method is used to determine the battery Soc.
  • Battery sizing depends on average load on the system, PV system output and losses in the auxillary systems(line losses, etc).
  • Methodology is simulated on a 13 bus system. 83% reduction in losses are is observed as a result of optimization.

On the maximization of a cost-effective PV sizing; towards an intelligent building[edit]

Kaplanis, S.; Kaplani, E.; Daviskas, E.A., "On the maximization of a cost-effective PV sizing; towards an intelligent building" Optimization of Electrical and Electronic Equipment, 2008. OPTIM 2008. 11th International Conference on , vol., no., pp.375,382, 22-24 May 2008 doi: 10.1109/OPTIM.2008.4602436

The issue of the most cost-effective configuration of a stand-alone PV plant to meet the loads with a high confidence level, is one of prime importance. The paper describes and compares two new approaches which when combined may provide much more reliable and economic PV sizing and performance, compared with the conventional methodology. There is outlined an evolution of PV sizing methodologies with an inbuilt level of intelligence which eventually maximizes the cost-effectiveness and the performance ratio of a stand alone PV plant. Comparison of results provided by three PV sizing methodologies is

presented and argued.

Notes:
  • Paper compares results provided by 3 PV sizing methods.
  • Static conventional PV sizing.
  • Statistical Fluctuation model in PV sizing.
  • 3rd Predictive management of PV system. Consists of Intelligent PV system + Load Management.
  • Studying statistical analysis of solar irradiance provides a sizing approach that makes the system cost effective and reliable.

Design and Implementation of Low Power Smart PV Energy System for Portable Applications Using Synchronous Buck Converter[edit]

Babu, B.C.; Sriharsha, S.; Kumar, A.; Saroagi, N.; Samantaray, S.R., "Design and Implementation of Low Power Smart PV Energy System for Portable Applications Using Synchronous Buck Converter," Electronic System Design (ISED), 2011 International Symposium on , vol., no., pp.260,266, 19-21 Dec. 2011 doi: 10.1109/ISED.2011.56

In this paper, synchronous buck converter based PV energy system for portable applications, especially low power device applications such as charging mobile phone batteries are considered. The converter topology used here is soft switching technique to reduce the switching losses which is found prominently in the conventional buck converter, thus efficiency of the system is improved and the heating of MOSFETs due to switching losses reduce and the MOSFETs have a longer life. The dc power extracted from the PV array is synthesized and modulated by the converter to suit the load requirements. Further, a charging method is studied with controller to regulate the battery voltage and current without overheating. As a result, the charging efficiency can be improved by soft switching technique. Besides, the performance is obtained less number of components and the developed system is cost effective and highly portable. The proposed system is simulated in the MATLAB-

Simulink environment and the practical implementation of the proposed converter is done to validate the theoretical results.

Notes:
  • PV systems for low power applications are considered.
  • Major chunk of losses attributed to MOSFET switching - 94% converter efficiency.
  • The convetrer maintains charging current at reasonable levels, which would otherwise affect battery life.
  • Lesser components, hence system is highly cost effective and portable.

I–V and P-V curves measuring system for PV modules based on DC-DC converters and portable graphical environment[edit]

Durán, E.; Ferrera, M.B.; Andújar, J.M.; Mesa, M.S., "I–V and P-V curves measuring system for PV modules based on DC-DC converters and portable graphical environment," Industrial Electronics (ISIE), 2010 IEEE International Symposium on , vol., no., pp.3323,3328, 4-7 July 2010 doi: 10.1109/ISIE.2010.5637972

The photovoltaic (PV) modules or arrays can be characterized by their I-V and P-V curves. These curves depend on solar irradiance and temperature. There are many ways to obtain these curves, but the using of DC-DC converters as variable resistance offers advantages over the rest. This paper presents a circuit solution based on scaled DC-DC converter using IGBT to obtain the I-V and P-V curves of the PV modules or arrays. A portable graphical environment (virtual instrument, VI) has been developed to adjust the parameters of the developed measuring system and show the I-V and P-V curves together and other parameters in real time. The experimental results for the system proposed using 1 kW single-ended primary inductance converter (SEPIC) are shown.
Notes:
  • DC-DC converter used to mimic a variable resistance to obtain P-V and I-V curves.
  • This method is highly flexible, gives fast response and has low cost.
  • Single Ended Primary Inductance converter (SEPIC) converter topology has been implemented.
  • Virtual Interface (VI) has been developed using LABVIEW.

Current-mode bi-directional single-inductor three-port DC-DC converter for portable systems with PV power harvesting[edit]

Yue Wen; Shao, L.; Fernandes, R.; Trescases, O., "Current-mode bi-directional single-inductor three-port DC-DC converter for portable systems with PV power harvesting," Power Electronics and Applications (EPE), 2013 15th European Conference on , vol., no., pp.1,10, 2-6 Sept. 2013 doi: 10.1109/EPE.2013.6634707

This work targets low-power portable electronic applications with PV power harvesting. A bidirectional dc-dc converter is required to interface the battery with the load and PV module. A new current-mode scheme is applied to the single-inductor three-port converter, where the peak and valley inductor current are controlled by two separate digital regulation loops. The controller is shown to regulate both the PV voltage and the load voltage in the presence of load and irradiance steps. In solar deficit mode, energy is transferred from the battery to the load indirectly through the PV node, eliminating the two input switches used in conventional dual-input, dual-output converters. The scheme is demonstrated on a digitally controlled 1 W harvester prototype.
Notes:
  • Controller used to regulate both solar PV voltage as well as load voltage.
  • In absence of solar radiation energy transfer occurs from battery to load indirectly through PV node.
  • Two cascaded DC-DC converters are used, one for MPPT and other to regulate load voltage.
  • Modes of operation
1) Solar deficit - Battery discharge (SOC ≠ 0)
2) Solar deficit - Lockout (SOC = 0)
3) Solar Excess - Charging (SOC ≠ 1)
4) Solar excess - (SOC = 1) Stops charging, tracks load power requirement.
  • Converter provides reasonable dynamic response and efficiency for low power PV application.

Model of smart solar PV charge controller[edit]

Wells, M., "Model of smart solar PV charge controller," Systems, Applications and Technology Conference (LISAT), 2011 IEEE Long Island , vol., no., pp.1,5, 6-6 May 2011 doi: 10.1109/LISAT.2011.5784245

The development of smart solar grids will help to provide concentration of power within the grid and eliminate the power losses seen when panels are working insufficiently. It will also allow switching between panels to provide optimal battery charging. Each panel will be characterized by their open circuit voltage and short-circuit currents. This paper presents approaches to implementation of this idea and various uses which will help analyze the functionality of a smart solar grid in the residential market. In particular, implementation of such a system would allow users to program switching between two, and eventually more, independently controlled solar cells, allowing for optimal battery charging according to the panels' electrical outputs. This platform therefore requires a large portion of programming to be integrated with the solar cells as well as the switching interface. Data will need to be stored and computations made to determine the optimal circuitry configuration. One constraint that is already a problem would be the number of cells which can be continually monitored by the program. More cells require either more time to compute data or a faster data processing center, either of which would cost money in the end. In the case of multiple solar cells producing similar output voltages, more than one switch may need to be turned on therefore allowing multiple solar cells, or panels, to take part in charging the battery. With a large portion of this design based solely on a software interface, it becomes hard to design hardware architecture that allows for faster processing. The limitations of the project are based on the limitations of the software developed. Overall performance increases in battery charging efficiency will help balance out any cost or time constraints that may occur during the implementation of such a project.
Notes:
  • Goals - Optimal charging, efficiency and independant control.
  • Determine solar cell producing optimal power output and monitor other cells to control power being produced.
  • Integration of computer software with hardware is essential to obtain required degree of control.

Energy efficient solar based digital electronic weighing machine[edit]

Rikame, S.N.; Kulkarni, P.W., "Energy efficient solar based digital electronic weighing machine," Computer and Communication Technology (ICCCT), 2014 International Conference on , vol., no., pp.355,360, 26-28 Sept. 2014 doi: 10.1109/ICCCT.2014.7001519

The aim of proposed system is to develop an energy efficient digital electronic weighing machine which operates with the help of solar PV panel. This system describes the design and implementation of energy efficient, low cost and portable solar powered digital electronic weighing system. The system has highly reduced circuitry as it utilizes a standalone microcontroller chip. As this machine does not use the electricity to charge, it saves the electrical energy. This article gives a detailed weighing controller design method. This system introduces the design and realization of automatic weighing system based on 8-bit high-precision PIC Controller. From hardware design and software design the paper introduces the interface circuit design between weighting sensor and PIC controller together with the application. The working principal of the emergency light circuit depends upon the status of light dependent register (LDR). When light dependent register is on that time emergency circuit is off and when light dependent register is off that time emergency circuit is on. The system designed measures weights ranging from 0-40 kg.
Notes:
  • System has reduced circuitry as it utilizes a standalone micro conrtroller chip, resulting in reduced losses in components.
  • Charge controller has been implemented to adjust PV output to circuit element. can also be used to charge battery.
  • Implemented system has a dual power source operating mode as well as an intelligent power switching mode.

The cooperated MPPT control of stand-alone PV Power generation system[edit]

Hong Wang; Bing Li, "The cooperated MPPT control of stand-alone PV Power generation system," Intelligent Control and Automation (WCICA), 2010 8th World Congress on , vol., no., pp.2228,2231, 7-9 July 2010 doi: 10.1109/WCICA.2010.5554297

With the application of renewable energy, the distributed energy network is researched and developed widely. This paper designed the distributed stand-alone PV generating system with battery backup. The coordinated MPPT control of several parallel modules is designed to increase PV utilizing efficiency. The multi-variable multi-loop controller is designed to control the currents of each module, the DC bus voltage and the AC voltage of inverter output. According to the different battery characteristics, the battery management is optimized for better performance and longer life time. The capacity and cost of the system can be optimized and decreased since the distributed energy generating and battery can provide the unintended power. 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.
Notes:
  • Co-ordinated MPPT control of several parallel modules to increase PV utilization efficiency.
  • PV voltage and currents are monitored and power is dynamically controlled by two DC-DC converters by varying system impedance.
  • MPPT algorithm has a fast convergence time which minimizes transients, providing reliable power quality.

Sizing and power management for a stand-alone PV system in cold climate[edit]

Chikh, A.; Chandra, A., "Sizing and power management for a stand-alone PV system in cold climate," Transmission and Distribution Conference and Exposition (T&D), 2012 IEEE PES , vol., no., pp.1,6, 7-10 May 2012 doi: 10.1109/TDC.2012.6674234

In this paper, we present a stand-alone PV/Battery system feeding a DC load under variable climatic conditions and load profile. A Lead-acid battery has been used to compensate the intermittent nature of solar energy. The PV system has been designed An MPPT method based on the optimal array conductance has been used. Moreover, the battery SOC has been used to protect the battery from damage. The entire system was applied to a typical house in the north of Quebec (Canada). The simulation results show that the proposed system guarantees a safe power transfer to the battery storage and the MPPT technique responds perfectly to rapid solar irradiance changes.
Notes:
  • MPPT method based on optimal array conductance has been used.
  • System is simulated on a typical house located north of Quebec (Canada).
  • Variable nature of PV power output leads to fast charge/ discharge action in batteries and speeds battery aging.
  • Various instances of variation in solar irradiation and battery charge levels have been simulated with close theoretical results.
  • Battery SOC is the parameter monitored to prevent battery damage.

Design of an off-grid PV system for the rural community[edit]

Rajeev, A.; Shanmukha Sundar, K., "Design of an off-grid PV system for the rural community," Emerging Trends in Communication, Control, Signal Processing & Computing Applications (C2SPCA), 2013 International Conference on , vol., no., pp.1,6, 10-11 Oct. 2013 doi: 10.1109/C2SPCA.2013.6749365

A requirement in rural local communities, remote from the conventional electric power grids is for off-grid power for portable and emergency access. This power is to be obtained from renewable energy considering the current energy scenario. Studies have been made in this field. The performance of a hybrid solar and battery system for grid support is studied in one of the papers. An off-grid electrical system for a village with less than 50 homes in rural Guatemala is discussed in another paper. These systems are used to power multiple homes, use complex and expensive hardware. A portable off-grid system to power a single rural home is designed. This project makes use of solar energy for powering small loads like LED (Light emitting diode) lamp, and mobiles. The system consists of a 5W PV (Photo Voltaic) solar cell which is placed in adequate sunlight. The PV panel is connected to a switching type charge controller. The switching type charge controller consists of a switching regulator and a battery charging section using microcontroller. The charge controller is connected to a rechargeable 6 Volt, 7 Ah (Ampere Hour) lead acid battery. The battery is then connected to an LED lamp using a dimmer circuit and a mobile charging point. The simulation is carried out using Power Sim and the results are in close agreement. Future scope is to use a higher rating PV panel and battery powering more applications for a longer time, a luminosity sensor and an A.C. charging point.
Notes:
  • System consists of 5W PV cell, charge controller and rechargeable 6V, 7Ah battery (Lead acid).
  • Charge controller consists of switching regulator and a battery charging section using microcontroller.
  • Switching regulator reaches efficiencies upto 88%, used to step down voltage to 8V DC.
  • Proposed device can be used to power rural homes with minimum investment.

A novel, digitally-controlled, portable photovoltaic power source[edit]

Zhenhua Jiang; Dougal, R.A., "A novel, digitally-controlled, portable photovoltaic power source," Applied Power Electronics Conference and Exposition, 2005. APEC 2005. Twentieth Annual IEEE , vol.3, no., pp.1797,1802 Vol. 3, 6-10 March 2005 doi: 10.1109/APEC.2005.1453291

This paper is to present a novel, digitally-controlled, portable photovoltaic (PV) power source that can be used as a standalone power source in remote missions or made on the jacket to power portable personal electronics. Since the solar cell has a nonlinear voltage-current characteristic, the photovoltaic power system has to track the solar array maximum power point to ensure the efficient operation. The battery is used to store energy when the solar irradiance is sufficient or the load is light and to provide energy to the load in the case of no sunlight or a heavy load. For advanced batteries such as lithium ion cells, the charging current or voltage should be limited in order to protect the battery. The charging and discharging currents are regulated by a charger and a discharger respectively. Since the battery voltage depends on its state-of-charge and the solar array peak-power voltage varies with temperature level, illumination level and age of the solar array, it is essential to cascade a power converter at the system output to obtain bus regulation. To reduce the solar array temperature, a shunt regulator is used to limit the charging current or voltage of the battery by dissipating the excess solar array power. In this paper, an integrated, multi-objective digital power controller for this PV power source is presented, and a state machine based model of the multiobjective controller is described. The large-signal behavior of the system is analyzed. The controller design is then verified by numerical simulation in the virtual test bed (VTB) environment.
Notes:
  • 3 modes of Operation
1) MPPT charging.
2) Constant voltage charging
3) Constant current charging
  • Battery charging voltage or charging current is regulated at a constant value.
  • System is simulated using virtual test bed (VTB) environment and results are verified.

PV module capacity assessment for a hybrid power generation system[edit]

Xin Gao; Irvine, S., "PV module capacity assessment for a hybrid power generation system," Computer Application and System Modeling (ICCASM), 2010 International Conference on , vol.6, no., pp.V6-31,V6-34, 22-24 Oct. 2010 doi: 10.1109/ICCASM.2010.5620063

A photovotic (PV) module assessment to a hybrid power generation system for Tibet Plateau was made in this paper. According to the average irradiance values gathered in Lhasa and the information of PV modules was gathered from literature provided by the manufacturers, the daily output power in watt-hours per m2 which could be expected from each of the modules based on the irradiance data was calculated, and the number of modules required to provide 1050 whr per day, including its area and cost, was assessed. By calculating and assessment, a proposal developed portable wind & solar hybrid power generating system was presented. The system proposed in this paper will greatly help to ease the shortage of electricity supply to herdsmen living in the wide grassland of Tibet Plateau.
Notes:
  • For control purposes, a combination of artificial intelligence methods as well as Perturbation and observation methods are used.
  • Solar radiation in Lhasa is about 195 kcal per square centimeter per year.
  • Two sharp crystalline silicon modules were inserted to compare light weight flexible modules with existing rigid technology.
  • Thin film modules are ideal to implement in PV hybrid system.

Photovoltaic charging station for electrical vehicles[edit]

Abella, M.A.; Chenlo, F., "Photovoltaic charging station for electrical vehicles," Photovoltaic Energy Conversion, 2003. Proceedings of 3rd World Conference on , vol.3, no., pp.2280,2283 Vol.3, 18-18 May 2003

A photovoltaic (PV) charging station for electrical vehicles (EV) has been designed and built. The general objective of this work is to study and promote the use of PV energy to charge EV in an urban area. The installation has a 9.24 kWp PV generator designed as a curved parking cover with 6 different tilt angles, from 12.5/spl deg/ to 50/spl deg/. Two electric charging towers manage the system energy flow, user control and system monitoring. Two grid connected inverters feed the energy to the EV and excess to the electrical grid. The installation has been designed as portable for demonstration purposes.
Notes:
  • 9.24 kWp PV generator is used.
  • Panels installed on curved parking cover with 6 different tilt angles from 12.5 degrees to 50 degrees.
  • 66 Pv modules of high efficiency m-Si material, 140Wp each.
  • Energy production is estimated to be 1193kWh/kWp.

Photovoltaic-Battery-Powered DC Bus System for Common Portable Electronic Devices[edit]

Lu, D.D.-C.; Agelidis, V.G., "Photovoltaic-Battery-Powered DC Bus System for Common Portable Electronic Devices," Power Electronics, IEEE Transactions on , vol.24, no.3, pp.849,855, March 2009 doi: 10.1109/TPEL.2008.2011131

Renewable energy sources based on photovoltaic (PV) along with battery-based energy storage necessitate power conditioning to meet load requirements and/or be connected to the electrical grid. The power conditioning is achieved via a dc-dc converter and a DC-AC inverter stages to produce the desired AC source. This is also the case even when the load is of dc type, such as the typical portable electronic devices that require AC adaptors to be powered from the AC mains. The letter presents a hybrid PV-battery-powered dc bus system that eliminates the DC-AC conversion stage, resulting in lower cost and improved overall energy conversion efficiency. It is also shown experimentally that the switching ac adaptors associated with the various commonly used portable electronic devices can be reused with the proposed dc bus system. A novel high-gain hybrid boost-flyback converter is also introduced with several times higher voltage conversion ratio than the conventional boost converter topology. This arrangement results in higher DC bus levels and lower cable conduction losses. Moreover, the voltage stress on the hybrid boost-flyback converter power switch is within half the output voltage. Experimental results taken from a laboratory prototype are presented to confirm the effectiveness of the proposed converter/system.
Notes:
  • Power conditioning is obtained via a DC-DC converter and a DC-DC inverter.
  • Objectives
1)Confirm experimentally that AC adapters operate properly even when powered from a DC bus.
2)Propose a new DC-DC converter configuration powered by a combination of a PV source and a battery while fulfilling DC bus requirements.
3)Propose a new high step-up ratio DC-DC converter for the DC bus system with a lower voltage stress.
  • Proposed configuration has an overall efficiency of 80% as opposed to 75% of conventional approaches.

A smart and simple PV charger for portable applications[edit]

Weichen Li; Yuzhen Zheng; Wuhua Li; Yi Zhao; Xiangning He, "A smart and simple PV charger for portable applications," Applied Power Electronics Conference and Exposition (APEC), 2010 Twenty-Fifth Annual IEEE , vol., no., pp.2080,2084, 21-25 Feb. 2010 doi: 10.1109/APEC.2010.5433522

A smart and simple PV charger circuit is presented in this paper for the portable applications, which is only composed of several analog chips to simplify the system structure. A three-mode charging solution is employed to meet the demands of the PV array and the lithium battery, which includes the maximum power point tracking (MPPT) mode, the constant-voltage mode and the current-limited mode. Suitable charging mode can be achieved automatically by the smart switch to improve the utilization of the PV array and to protect the battery. The fractional open-circuit voltage method is employed to realize the MPPT performance due to its simple implementation performance. Furthermore, the proposed charger can be integrated into an IC chip to reduce the size and make it more attractive in the portable applications. At last, a 60 W prototype is built and tested to verify the effectiveness of the proposed solution.
Notes:
  • Fractional open circuit voltage (FOCT) algorithm is used for MPPT method.
  • PV array selected from 16.5 to 20 V.
  • Charging circuit consists of a step-down buck converter.
  • Proposed charger solution can be integrated into an IC chip to reduce system size and improve power density.
  • Maximum power output of array is 60W.

Energy management for solar battery charging station[edit]

Su Sheng; Chung-Ti Hsu; Peng Li; Lehman, B., "Energy management for solar battery charging station," Control and Modeling for Power Electronics (COMPEL), 2013 IEEE 14th Workshop on , vol., no., pp.1,8, 23-26 June 2013 doi: 10.1109/COMPEL.2013.6626426

This paper presents a new system architecture for a low cost photovoltaic (PV) battery charging station that can balance: 1) the charging time of each individual battery and 2) the total charging time of all batteries in the system. The control strategy for the new system first charges each individual battery to either the same voltage or same state of charge (SOC) level and then charges multiple batteries in parallel simultaneously. As the paper demonstrates, this method can increase solar energy exploitation so that the total charging time of all batteries is decreased. Experimental results of a prototype of the system validate the effectiveness of the proposed control strategy.

High-Performance Stand-Alone Photovoltaic Generation System[edit]

R.-J. Wai, W.-H. Wang, and C.-Y. Lin, “High-Performance Stand-Alone Photovoltaic Generation System,” IEEE Transactions on Industrial Electronics, vol. 55, no. 1, pp. 240–250, Jan. 2008.

This study develops a high-performance stand-alone photovoltaic (PV) generation system. To make the PV generation system more flexible and expandable, the backstage power circuit is composed of a high step-up converter and a pulsewidth-modulation (PWM) inverter. In the dc-dc power conversion, the high step-up converter is introduced to improve the conversion efficiency in conventional boost converters to allow the parallel operation of low-voltage PV arrays, and to decouple and simplify the control design of the PWM inverter. Moreover, an adaptive total sliding-mode control system is designed for the voltage control of the PWM inverter to maintain a sinusoidal output voltage with lower total harmonic distortion and less variation under various output loads. In addition, an active sun tracking scheme without any light sensors is investigated to make the PV modules face the sun directly for capturing the maximum irradiation and promoting system efficiency. Experimental results are given to verify the validity and reliability of the high step-up converter, the PWM inverter control, and the active sun tracker for the high-performance stand-alone PV generation system.

Single variable based variable step size maximum power point tracker for stand-alone battery storage PV systems[edit]

Ahmed, E.M.; Shoyama, M., "Single variable based variable step size maximum power point tracker for stand-alone battery storage PV systems," Industrial Technology (ICIT), 2011 IEEE International Conference on , vol., no., pp.210,216, 14-16 March 2011 doi: 10.1109/ICIT.2011.5754374

Recently, maximum power point trackers (MPPTs) that based on single variable (IPV or VPV) have a great attention. That is due to their simplicity and easiness in implementation, when compared to the other tracking techniques. In this paper, two methods have been proposed to design a variable step size MPPT using only a single current sensor for stand-alone battery storage PV systems. These methods utilize only the relationship between the PV array measured current and the converter duty cycle (D) in order to adapt automatically the step change in the duty cycle to reach the maximum power point (MPP) of the PV array. A comparison has been held between the proposed methods to investigate their performance in transient and steady state as well using PSIM software. Furthermore, a hardware implementation for one of the proposed methods has presented using field programmable gate arrays (FPGAs) to verify the performance of the suggested schemes.
Notes:
  • The efficiency of the MPPT algorithm increases if it tracks only one variable.
  • Main objective is to find a certain measure (Q) that addresses the trade off between transient and steady state performance.
  • Steady state oscillations are greatly improved due to variable step approach.
  • The step size depends on the relationship between array current and converter duty cycle.

Effects of mismatch losses in photovoltaic arrays[edit]

Charles E. Chamberlin, Peter Lehman, James Zoellick, Gian Pauletto, Effects of mismatch losses in photovoltaic arrays, Solar Energy, Volume 54, Issue 3, March 1995, Pages 165-171, ISSN 0038-092X, http://dx.doi.org/10.1016/0038-092X(94)00120-3.

Experimental and modeling results on the effects of mismatch losses in photovoltaic arrays are presented. Field tests conducted on each of the 192 modules are used to describe the variation in the properties of production run photovoltaic modules. Module specific estimates of a five-parameter module model are obtained by nonlinear regression. Mathematical models of four-module parallel string and series block photovoltaic array performance based on the five-parameter module model are developed and used to evaluate the variation in maximum output power and mismatch loss of arrays with random module orderings. Module maximum output power averaged 14% below the nameplate rating and exhibited a coefficient of variation of 2.1%. Mismatch losses were very small, never exceeding 0.53%. No differences between parallel string and series block arrays in array maximum output power were observed.

Optimization of perturb and observe maximum power point tracking method[edit]

N. Femia, G. Petrone, G. Spagnuolo, and M. Vitelli, “Optimization of perturb and observe maximum power point tracking method,” IEEE Transactions on Power Electronics, vol. 20, no. 4, pp. 963–973, Jul. 2005.

Maximum power point tracking (MPPT) techniques are used in photovoltaic (PV) systems to maximize the PV array output power by tracking continuously the maximum power point (MPP) which depends on panels temperature and on irradiance conditions. The issue of MPPT has been addressed in different ways in the literature but, especially for low-cost implementations, the perturb and observe (P&O) maximum power point tracking algorithm is the most commonly used method due to its ease of implementation. A drawback of P&O is that, at steady state, the operating point oscillates around the MPP giving rise to the waste of some amount of available energy; moreover, it is well known that the P&O algorithm can be confused during those time intervals characterized by rapidly changing atmospheric conditions. In this paper it is shown that, in order to limit the negative effects associated to the above drawbacks, the P&O MPPT parameters must be customized to the dynamic behavior of the specific converter adopted. A theoretical analysis allowing the optimal choice of such parameters is also carried out. Results of experimental measurements are in agreement with the predictions of theoretical analysis.

Stability analysis of FPGA based perturb and observe method MPPT charge controller for solar PV system[edit]

Saini, T.; Raveendhra, D.; Thakur, P., "Stability analysis of FPGA based perturb and observe method MPPT charge controller for solar PV system," Engineering and Systems (SCES), 2013 Students Conference on , vol., no., pp.1,5, 12-14 April 2013 doi: 10.1109/SCES.2013.6547545

In recent years, renewable energy sources have become most popular day by day to generate electrical energy. Among all other types of renewable energy sources, solar is one of the best alternatives for conventional sources as it offers more advantages. This paper is mainly concentrated on the area of charge controller in solar PV power conditioning system. In this paper, a P&O method MPPT charge controller is designed and it is converted into digital domain to use in FPGA. Compared to analog controllers, digital controller offers more advantages like high accuracy, less effected by noise etc., MPPT charge controller is designed to perform 1) to convert the variable DC electrical energy which is coming from solar into fixed DC and 2) to track the maximum power from the solar PV module under all operating conditions. This fixed DC can be used to feed the DC loads or charge the batteries.
  • Field programmable gate array (FPGA) IC based perturbation and observation method is been implemented.
  • Power conditioning systems play an important role in PV based systems.
  • FPGA is used to control MOSFET switching.
  • As per phase margins obtained from bode plots the system os stable for line and load variations.

MPPT Solar Charge Controller for High Voltage Thin Film PV Modules[edit]

Grzesiak, W., "MPPT Solar Charge Controller for High Voltage Thin Film PV Modules," Photovoltaic Energy Conversion, Conference Record of the 2006 IEEE 4th World Conference on , vol.2, no., pp.2264,2267, May 2006 doi: 10.1109/WCPEC.2006.279624

The work deals with a PV battery charge regulator assigned for advanced CdTe modules of output voltage much higher than the popular values of the order 12 or 24 V nominally. As at the same time most of the nominal PV autonomous installation voltages generally remain on the 12 or 24 V level because of convenience, technical tradition and battery features- this high DC module's voltage has to be transformed to a proper lower value by means of DC/DC inverter of possibly high efficiency. A new own developed 60/12 V charge controller solution is presented. This charge controller is equipped with a "step-down" inverter version furnished with modern MPP tracking technique. The choice of MPPT algorithm and its realisation by means of microprocessor are explained and discussed as well as final test and measurement results. Very satisfactory exploitation results permit to estimate the solution as a valuable one for the new high voltage modules' market.
  • CdTe modules are generally used as HV modules.
  • Paper deals with modules operating in 60 to 80 V range.
  • 12V battery is charged with only 18.6% of power output of 70W module.
  • Step down inverter with a ratio of 5:1 is utilized.
  • Efficiency obtained is 86% at nominal 60V 50W operating point.

Design and implementation of 2 channels turbidity sensor modules[edit]

Joongki Park; Kyunchul Park; Kipung Han; Kwangro Park, "Design and implementation of 2 channels turbidity sensor modules," Ubiquitous Robots and Ambient Intelligence (URAI), 2013 10th International Conference on , vol., no., pp.447,450, Oct. 30 2013-Nov. 2 2013 doi: 10.1109/URAI.2013.6677307

The turbidity has been classified as a basic item to measure water quality. This research team has developed a small turbidity sensor module to measure permanent turbidity based on moving objects that may freely swim on or under the water. This paper describes benchmark test results of the 2 channel turbidity sensor module with problems improved from the existing turbidity sensor module and the commercial products. The 2 channel turbidity sensor module not only has acquired the authorized test report issued by the Korea Testing Laboratory but also showed the performance within acceptable range of error at water quality under 8NTU comparing to the commercial products.
  • Turbidity has been classified as the basic criteria to measure water quality.
  • 2 Channels utilized-
1) for light emmiting sensor
2) for light receiving sensor.
  • Improved capability to shield natural light which interferes with turbidity measurement.

An IR turbidity sensor: design and application [virtual instrument][edit]

Postolache, O.; Girao, P.; Pereira, M.; Ramos, H., "An IR turbidity sensor: design and application [virtual instrument]," Instrumentation and Measurement Technology Conference, 2002. IMTC/2002. Proceedings of the 19th IEEE , vol.1, no., pp.535,539 vol.1, 2002 doi: 10.1109/IMTC.2002.1006899

This paper presents an infrared turbidity sensor characterised by a flexible structure that permits the materialisation of different turbidity measurement schemes (transmission, scattering, ratio) in order to increase the measurement accuracy limiting the critical design factors and diminishing the common mode factors. As parts of the work are mentioned the design, implementation, calibration and test of the new turbidity sensor. For an automatic measurement process different "virtual instrument" components are developed and different intelligent processing structures based on neural network and fuzzy systems are implemented in order to obtain the turbidity information.
  • Reduction in transparency of liquid is caused by undissolved matter.
  • Turbidity measurement is heavily dependant on the wavelenght of light used.
  • Main components - 3 IR LEDs, 1 IR photodiode, microcontroller.
  • Error within ±1% is maintained in measurements.

Turbidity sensor for underwater applications[edit]

Mylvaganaru, S.; Jakobsen, T., "Turbidity sensor for underwater applications," OCEANS '98 Conference Proceedings , vol.1, no., pp.158,161 vol.1, 28 Sep-1 Oct 1998 doi: 10.1109/OCEANS.1998.725727

Turbidity is one of the main hindrances, when using optical methods, in achieving good imaging and ranging qualities in underwater applications of remote sensing, ROVs and instruments. The present paper gives the principles of operation and design of an optical turbidity meter. The operation of the meter is based on illuminating the medium with light of selected wavelengths and measuring the backscattered light. Many series of measurements were made with the sensor under discussion based on secondary standard calibration mediums of formazin. The experimental results in calibration mediums and from actual underwater applications are presented in this paper. Finally, the performance of the sensor system in practical applications is described. The main aspects of the sensor electronics is also presented
  • Turbidity is measured in NTU (Nephelometric turbidity unit).
  • Potable water should not exceed 0.5 NTU.
  • Due to low energy consumption design, energy consumed in 10 minutes is less than 10 micro watts.

An intelligent turbidity and temperature sensing unit for water quality assessment[edit]

Postolache, O.; Pereira, J.M.D.; Girao, P.S., "An intelligent turbidity and temperature sensing unit for water quality assessment," Electrical and Computer Engineering, 2002. IEEE CCECE 2002. Canadian Conference on , vol.1, no., pp.494,499 vol.1, 2002 doi: 10.1109/CCECE.2002.1015276

This paper reports the development of an intelligent turbidity and temperature-sensing unit for water quality assessment. The intelligent unit is based on an original turbidity sensor, which includes three IR light sources and a single IR detector, and on a thermistor-based temperature sensor. The system is designed around a PIC16F877 microcontroller that performs tasks such as sensor control, data acquisition, data processing and communications. The proposed turbidity sensor allows a reduction in the effects of detector-to-defector variability, light source intensity variations and water absorbance. For sensor data processing, different solutions, including neural processing, are considered and discussed. Elements of the sensing unit calibration, autocalibration, testing and RS232 communication between the microcontroller and a PC are also presented.
  • System is designed around PIC16F877 micro controller.
  • 3 LEDs (LD271) are used as light sources. Light to voltage converter includes a silicon photodiode and a transimpedance amplifier.
  • Serial communication is used to transmit data.
  • Obtained deviation is wihthin ±1%.
  • For temperature sensor errors are less that 0.2 degree celcius.

Design, Analysis, and Realization of a Turbidity Sensor Based on Collection of Scattered Light by a Fiber-Optic Probe[edit]

Prerana; Shenoy, M.R.; Pal, B.P.; Gupta, B.D., "Design, Analysis, and Realization of a Turbidity Sensor Based on Collection of Scattered Light by a Fiber-Optic Probe," Sensors Journal, IEEE , vol.12, no.1, pp.44,50, Jan. 2012 doi: 10.1109/JSEN.2011.2128306

We propose a method for sensing the turbidity of a solution using a fiber-optic bundle probe in conjunction with a mirror. We have estimated turbidity in terms of total interaction coefficient, a parameter that contains strong signature of the turbidity of a liquid. A simple model based on geometrical optics and also a light-scattering model based on Monte Carlo simulations are employed to estimate the power collected by the optical fiber probe. The method is simple, and should be useful for detecting suspended impurities in a liquid even in small quantities.
  • Fibre optic probe or optrode is a popular mode for extrinsic sensing operations.
  • Turbidity is estimated in terms of Total interaction coefficient.
  • The maximum sensitivity is obtained at a particular position of optrode with respect to the mirror.
  • Maximum sensitivity is dependant on diameter of optic fibre and distance between optrode and miror.

Energy storage systems—Characteristics and comparisons[edit]

H. Ibrahim, A. Ilinca, J. Perron, Energy storage systems—Characteristics and comparisons, Renewable and Sustainable Energy Reviews, Volume 12, Issue 5, June 2008, Pages 1221-1250, ISSN 1364-0321.

Electricity generated from renewable sources, which has shown remarkable growth worldwide, can rarely provide immediate response to demand as these sources do not deliver a regular supply easily adjustable to consumption needs. Thus, the growth of this decentralized production means greater network load stability problems and requires energy storage, generally using lead batteries, as a potential solution. However, lead batteries cannot withstand high cycling rates, nor can they store large amounts of energy in a small volume. That is why other types of storage technologies are being developed and implemented. This has led to the emergence of storage as a crucial element in the management of energy from renewable sources, allowing energy to be released into the grid during peak hours when it is more valuable.

The work described in this paper highlights the need to store energy in order to strengthen power networks and maintain load levels. There are various types of storage methods, some of which are already in use, while others are still in development. We have taken a look at the main characteristics of the different electricity storage techniques and their field of application (permanent or portable, long- or short-term storage, maximum power required, etc.). These characteristics will serve to make comparisons in order to determine the most appropriate technique for each type of application.

Low power photovoltaic system for energy supplying for small loads[edit]

Batista, F.A.B.; Peraca, M.T.; Petry, C.A., "Low power photovoltaic system for energy supplying for small loads," Industry Applications (INDUSCON), 2012 10th IEEE/IAS International Conference on , vol., no., pp.1,6, 5-7 Nov. 2012 doi: 10.1109/INDUSCON.2012.6452136

This paper presents the development of a low power photovoltaic system for energy supplying for small loads in emergency situations. The system consists of three power converters that work to charge batteries, boost voltages and provide an alternating signal to the load. The factors considered in the selection of each converter, their main characteristics and design equations are presented. The major contribution of the proposed system is its simplicity and reduced size and weight. Experimental results show the stand-alone operation of each converter and a prototype for the complete system.
  • Proposed system contains PV panel with maximum output of 3W.
  • DC-DC boost conveter is used.
  • System gives output of 30W at a square alternating wave of 155V.

Photovoltaic projects for decentralized power supply in India: A financial evaluation[edit]

M. R. Nouni, S. C. Mullick, and T. C. Kandpal, “Photovoltaic projects for decentralized power supply in India: A financial evaluation,” Energy Policy, vol. 34, no. 18, pp. 3727–3738, Dec. 2006.

The present study concentrates on photovoltaic (PV) projects for providing decentralized power supply in remote locations in India. Results of a techno-economic evaluation are presented. Some PV projects in the capacity range 1–110 kWp, that have either been implemented or are under implementation, have been considered. An analysis of the capital cost of the PV projects and sub-systems has been undertaken. Levelized unit cost of electricity (LUCE) has been estimated for eighteen select locations situated in different geographical regions of the country. The LUCE is found to vary in the range of Rs. 28.31–59.16/kW h (US$ 0.65–1.35/k Wh) for PV projects in the capacity range 1–25 kWp. In view of high unit cost of electricity from PV projects, need for financial incentives has been examined from the perspective of users. A sensitivity analysis has also been undertaken.

Photovoltaic systems for small-scale remote power supplies[edit]

Jenkins, N., "Photovoltaic systems for small-scale remote power supplies," Power Engineering Journal , vol.9, no.2, pp.89,96, April 1995 doi: 10.1049/pe:19950204

This article considers the technical aspects of using photovoltaic systems for small power supplies where a connection from a main electricity distribution network is not appropriate. The technology of the various components of a photovoltaic power system is discussed and the overall system design considered. Typical applications of photovoltaic systems are described.
  • The paper discusses how the sun can be utilized as an energy resource, PV energy conversion as well as inclusion of PV systems in power systems.
  • Provides good reading material for solar PV modules to be used in conjunction with conventional systems.

An inverter using buck-boost type chopper circuits for popular small-scale photovoltaic power system[edit]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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.