Showing papers on "Grid-connected photovoltaic power system published in 1982"

New solar cell power supply system using a boost type bidirectional DC-DC converter

Abstract: New solar cell power supply system is presented, in which the boost type bidirectional dc-dc converter and the simple control circuit with a small monitor solar cell are employed to track the maximum power point of the solar array. It is confirmed by the experiment that the new system has the sufficiently precise tracking operation performance and the satisfactorily high power efficiency. Also, a comparison of the power efficiencies is made with theoretically as well as experimentally on the new and the conventional solar cell power supply systems. As a result, it is revealed that the new system is superior to the conventional one in the power efficiency.

Solar cell power supply circuit

Abstract: A solar cell power supply circuit for use in a calculator or equipment is disclosed. It includes a solar cell or cells, a back-up capacitor connected to the solar cells, and a circuit element connected to be responsive whether the electromotive force from the solar cells lies within a range of operation for a load element of the solar cells, typically an LSI semiconductor device. The back-up capacitor starts charging when the electromotive force of the solar cells falls out of the range of operation for the load element. Preferably, an alarm sound is delivered when the electromotive force of the solar cells is poor.

An Analysis of the Harmonics and Power Factor Effects at a Utility Intertied Photovoltaic System

Abstract: This paper outlines the harmonics and power-factor characteristics and effects of a single residential photovoltaic (PV) installation using a line-commutated inverter. The data were taken during a five-day measurement program conducted at the John F. Long House, which is a prototype residential PV installation located in Phoenix, Arizona. The magnitude and phase of various currents and voltages from the fundamental to the 13th harmonic were recorded both with and' without the operation of the PV system. A candidate method of modeling the installation for computer studies of larger concentrations is given.

A Low Distortion PWM DC-AC Inverter, with Active Current and Voltage Control, Allowing Line-Interfaced and Stand-Alone Photovoltaic Applications

Abstract: The energy transfer between a photovoltaic solar panel and the grid can be realized by means of a DC-AC inverter, which is described in this paper. A reliability study of the entire system (i.e. the solar panels and the inverter) shows that the voltage generated by the solar panel matrix has to be low (≪ 100 V). The stability conditions of the energy transfer dictate a current source behaviour of the inverter. This is realized by means of an appropriate feedback system. In this way a voltage inverter type can be used instead of the current inverters which are usually proposed, so the relatively heavy and expensive inductors can be omitted. This also allows the inverter to be used as an AC voltage power supply, in the absence of the power grid.

Matching the Characteristics of Batteries with Solar Cell Modules

Abstract: This paper puts together the characteristics of the storage battery commonly used in worldwide photovoltaic applications with those of the photovoltaic generator and of the solar source The natural matching of these characteristics may be exploited in meeting the typical requirements of the user If the module is properly designed, and if due care is taken in battery installation for passive temperature control, there is no need for complex regulation or periodic adjustment, A well-designed photovoltaic module can function as both generator and controller, providing enhanced system reliability, lower system cost, and simpler operation for the user The critical design parameter, the charging voltage delivered to the battery by the module, is determined by the number of cells in the series string

Performance Characteristics of 350 kW Photovoltaic Power System for Saudi Arabian Villages

Abstract: The performance characteristics of the Saudi Solar Village Project, one of several projects sponsored by the Saudi Arabian-United States Program for Cooperation in the Field of Solar Energy (SOLERAS), a five-year jointly-funded $100M program, are presented in this paper. It is original and far reaching with respect to the scope and variety of solar technologies involved as well as the unique joint and cooperative manner in which the technology involved is developed and transferred. One of the program's objectives is to enhance the quality of life in rural areas within traditional ways of life. The Saudi Solar Village Project thus seeks to determine the feasibility of utilizing solar power to generate electricity in remote areas not served by existing electric power grid facilities. Details of the design of the 350 kW photovoltaic power system and its various subsystems are presented and the performance of the system and subsystems during initial acceptance testing of the system are discussed in this paper...

Residential photovoltaic power conditioning technology for grid connected applications

Abstract: Major advances in photovoltaic (PV) Power Conditioning (PC) with respect to performance and low-cost potential have been made. Solutions have been obtained to interface and control problems related to adapting available inverter designs to the grid-connected, residential photovoltaic experiments. A description is presented to contributing research and development activities. Attention is given to aspects of residential systems experience, conceptual design studies, questions of optimum topology development, and promising advanced designs for residential PV provided by development efforts of the private sector.

Design of electronic optimizer for solar electric drive system

Abstract: There has been considerable interest in the use of solar electrical converters for supplying electric drive motors in pumping schemes for rural areas. The optimum control of solar electric drive motors is desirable because it leads firstly, to higher apparent efficiency of solar energy conversion, and, secondly, to reduced cost per useful watt. Although the ‘fuel’ for solar drives is free, the cost of solar cells is high. Optimization means that smaller areas of solar panels are required, thus reducing the overall cost of the solar drive system. The present investigation has been directed towards the development of a reliable electronic controller, which would ensure stable and optimal performance characteristics of solar electric-powered pumping scheme over a broad range of operating conditions. The design goals are low cost, reasonable accuracy, control capability and efficient utilization of the electrically converted solar power. The developed electronic optimizer provides constant voltage operation of the solar generator so that maximum power can be delivered to the drive motor for any light intensity. The main part of the optimizer is a servo chopper. The chopper operation is automatically adjusted so that the overall system efficiency is always maintained at a maximum value. Details of the electronic optimizer circuits are given and the overall system performance is investigated. Valuable information for the design and operation of the solar electric drive system with the electronic optimizer is gained from this analysis.

Design description of the Tangaye Village photovoltaic power system

Abstract: The engineering design of a stand alone photovoltaic (PV) powered grain mill and water pump for the village of Tangaye, Upper Volta is described. The socioeconomic effects of reducing the time required by women in rural areas for drawing water and grinding grain were studied. The suitability of photovoltaic technology for use in rural areas by people of limited technical training was demonstrated. The PV system consists of a 1.8-kW (peak) solar cell array, 540 ampere hours of battery storage, instrumentation, automatic controls, and a data collection and storage system. The PV system is situated near an improved village well and supplies d.c. power to a grain mill and a water pump. The array is located in a fenced area and the mill, battery, instruments, controls, and data system are in a mill building. A water storage tank is located near the well. The system employs automatic controls which provide battery charge regulation and system over and under voltage protection. This report includes descriptions of the engineering design of the system and of the load that it serves; a discussion of PV array and battery sizing methodology; descriptions of the mechanical and electrical designs including the array, battery, controls, and instrumentation; and a discussion of the safety features. The system became operational on March 1, 1979.

Power Conditioning in Solar Photovoltaic Array Applications

Abstract: The design and implementation of appropriate power conditioning apparatus for the interconnected operation of PV arrays with the utility grid are presented. Problems of maximum power transfer from the PV array to the utility grid, reliability of the interconnected system operation and component protection are addressed. Because of the intermittent nature of the available solar energy, the need for conversion of dc electrical power to ac and the fluctuating loads of the utility system, optimization methodologies and associated equipment are developed for converting the maximum available solar power to electrical form and transfering it to the grid. A dual methodology is adopted containing a theoretical — system simulation — study of the performance of the interconnected system and a parallel experimental facility for the implementation of the system design. Results indicate higher energy transfer efficiencies in combination with an increased quality and reliability of performance of the PV array — utility grid system.

A 2 kW Photovoltaic Power Generating System Using a-Si Solar Cells

Abstract: We have developed integrated amorphous silicon (a-Si) solar panels and have applied them to an electric power generating system. The integrated a-Si solar panel consists of 20 integrated type a-Si solar cell modules, each with a size of 10 cm ×10 cm, which have been developed for use in an electric power generating system. The power generating system is set in an experimental model house. The output performance of the solar panels has been measured, and a peak amount of 2 kW was obtained. The conversion efficiency decreased about 10% within one month and then became stable. This stability has continued until the present time. The initial degradation of the conversion efficiency mainly depends on the degradation of the fill factor. It has been confirmed that electric power generating systems using a-Si solar panels are already effective enough for practical use.

Regulated Converter Circuit for Direct Photovoltaic Energy Feedback into the Power Grid

Abstract: A new regulated utility interactive (UI) inverter for direct photovoltaic energy feedback to the mains has been realized. The inverter acts as a current source, its output is a sinewave with negligible harmonic distortion and has a projected efficiency of over 90%. A novel maximum power tracking (MPT) strategy based on a simple current peak error detection is described.

Evaluation of Solar Photovoltaic Power Systems

Abstract: This paper describes a method of measuring and recording solar radiation data in a suitable form for the design of solar photovoltaic power systems. A prototype instrument has been developed which could be located at prospective sites for the collection of solar radiation data. A similar instrument is also being developed to evaluate the performance of photovoltaic power systems by integrating array and load currents.

High-Efficiency Spectrophotovoltaic System for Orbital Power Generation

Abstract: An analysis was performed to determine the economic feasibility of a concentrating Spectrophotovoltaic orbital electrical power generation system, capable of output power levels on the order of 100 kW. In this system dichroic beamsplitting mirrors are used to divide the solar spectrum into several wavebands. These mirrors consist of transparent substrates coated on the frontside with multilayer stacks of transparent dielectric materials. With this technique very high reflectivities can be achieved over a well-defined spectral region. Wideband antireflection coatings are applied to the back to insure good transmission of the nonreflected part of the spectrum. Absorption of the reflected and transmitted wavebands by solar cells with matched energy bandgaps increases the cell efficiency while decreasing the amount of heat which must be rejected. The optical concentration is performed in two stages. The first concentration stage employs a Cassegrain-type telescope, resulting in a short system length. The output from this stage, after being spectrally selected by dichroic beamsplitters, is directed to compound parabolic concentrators which comprise the second stage of concentration. In order to determine the optimum energy bands, "ideal" efficiencies for one-, two-, three-, and four-cell systems were calculated under 1000 sun, AMO conditions. The efficiencies ranged from 32.2% for a one-cell system to 52.8% for a four-cell system. Various combinations of Ge, Si, GaAs, and GaP were chosen to calculate more reasonable efficiencies. Account was taken of losses due to grid shadowing, cell reflection, dichroic mirrors and nonunity spectral response. Oneand four-cell systems were found to be less efficient than most of the twoand three-cell systems which had efficiencies on the order of 2697o-33%. A cost tradeoff analysis was performed to determine an optimum system configuration. The primary mirror was found to be responsible for 70%-85% of the system cost. Neglecting solar cell development cost, the twoand three-cell systems were found to be the most cost effective. The optimum system consisted of an jj/3.5 optical system, a beamsplitter to divide the spectrum at 0.9 /im, and two solar cell arrays, GaAs and Si. For a 100-kW power level, with solar cells maintained at a temperature of 300 K, the primary mirror diameter was calculated to be 20.43 m and the projected cost per peak watt of this system is $2.52/Wp.

Solar electricity-a low power technology

Abstract: The author examines the future potential of solar power with regard to its applications. He suggests that although the large size and small power output of solar cell electric systems are obstacles to high power usage, realistic low power applications can make a valuable contribution to world energy needs

Remote area applications of solar cell technology

Abstract: Although still expensive, silicon solar cell arrays are becoming increasingly common for some specialised remote area applications. Within Australia solar photovoltaic generators are being used to provide power for microwave radio repeater stations, VHF subscriber radiotelephone systems, UHF small capacity radio systems, as well as many other professional and commercial applications. In all of this plant it is vital to be able to provide reliable low maintenance primary power. A new generation of low power consumption communication equipment has made it possible to completely power broadband radio relay repeaters using only the solar source with power storage being provided by storage batteries of the pure-lead positive pasted-plate type. Several years of operational experience in remote locations have now been obtained with this solar generating equipment.

Power supply system for a camera

Abstract: Power supply system for a camera has a parallel circuit consisting of a main battery and a solar battery in order to supply a load in the camera with power from one of the two power sources or from both power sources as a function of the type of process which the load has to carry out, for example triggering a shutter or light measurement. Diodes are connected in series with the two power sources in order to prevent a current flowing from one of the power sources into the other. The main battery and the solar battery are connected to a common supply line via a switch. The main battery can be connected via a switch or switches to the common supply line whilst the solar battery is connected directly and continuously to the solar battery, by-passing the switch or the switches.

Grid-connected distributed solar power systems

Abstract: In the US today, many companies are developing and marketing small, grid-connected wind, photovoltaic and solar thermal electric power systems. The effect these systems have on utility transmission and distribution is unknown. Presented are some critical, though often ignored, technical and economic issues. Protection of the utility system and nonsolar customers requires suitable interface equipment; most analyses ignore the cost of this equipment. Purchase decisions must mirror reality; most anlayses use life-cycle costing. Distributing, installing, and marketing small, distributed solar systems is very costly; most analyses grossly underestimate these costs.