Energy management for solar battery charging station[edit | edit source]
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 | edit source]
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 | edit source]
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 | edit source]
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 | edit source]
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 | edit source]
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 | edit source]
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 | edit source]
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 | edit source]
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 | edit source]
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 | edit source]
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 | edit source]
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 | edit source]
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 | edit source]
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 | edit source]
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 | edit source]
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.
