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Showing papers on "Photovoltaic system published in 1990"


Book
31 Dec 1990
TL;DR: In this article, the authors present a review of renewable energy technologies, including photovoltaic power technology, wind power technologies, wave power, and geothermal energy technologies with a focus on using energy efficient technologies.
Abstract: 1. Principles of Renewable Energy 2. Solar Radiation and the Greenhouse Effect 3. Solar Water Heating 4. Other Solar Thermal Applications 5. Photovoltaic Power Technology - PV 6. Hydropower 7. Wind Resource 8. Wind Power Technology 9. Biomass Resources from Photosynthesis 10. Bioenergy Technologies 11. Wave Power 12. Tidal-current and Tidal-range Power 13. Ocean Gradient Energy: OTEC and Osmotic Power 14. Geothermal Energy 15. Energy Systems: Integration, Distribution and Storage 16. Using Energy Efficiently 17. Institutional and Economic Factors Review 1: Electrical Power Review 2: Fluid Dynamics Review 3: Heat Transfer Review 4: Solid State Physics for Photovoltaics Review 5: Units and Conversions: Algebraic Method Appendix A: Units and Conversions Appendix B: Data Appendix C: Some Heat Transfer Formulas Appendix D: Comparisons of Technologies Short Answers to Selected Problems Index

1,173 citations


Journal ArticleDOI
TL;DR: In this paper, the cost and the effect on utility reliability of rapidly changing PV (photovoltaic) generation on a partly-cloudy day were investigated and a methodology was presented to assess the cost of such fluctuations in PV generation and their effect on a utility's ability to serve its load.
Abstract: The cost and the effect on utility reliability of rapidly changing PV (photovoltaic) generation on a partly-cloudy day were investigated. When cloud shadows move across a PV array, the array's power output is reduced. It resumes full production when the shadow moves away. The utility must follow these changes with other types of generation. Under certain cloud conditions, these changes can be large and fast. A methodology is presented to assess the cost of such fluctuations in PV generation and their effect on a utility's ability to serve its load. A case study of one large utility in Kansas is performed using this technique. >

169 citations


Journal ArticleDOI
TL;DR: In this article, a technique is presented to improve the performance of a photovoltaic powered permanent magnet DC motor coupled to a screw-type volumetric water pump using a solid-state electric array reconfiguration controller, which senses the radiation as low, medium, or high.
Abstract: A technique is presented to improve the performance of a photovoltaic (PV) powered permanent magnet DC motor coupled to a screw-type volumetric water pump. The method uses a solid-state electric array reconfiguration controller (EARC), which senses the radiation as low, medium, or high. The controller chooses one favorable set of I-V characteristics for starting and another favorable set of I-V characteristics for steady-state operation. This is done by switching the solar panels, depending upon the starting current requirements and the irradiance level, from a parallel to series-parallel to series connection. This produces a sufficient starting current, especially at low and medium radiation levels, which considerably improves the pump's performance, particularly in the early morning, in the late evening, and on cloudy days, providing valuable extra pumping hours for the user. >

131 citations


Proceedings ArticleDOI
21 May 1990
TL;DR: In this paper, the potential benefits of distributed grid-connected photovoltaic generation for utility distribution systems were evaluated using a test case at the Pacific Gas and Electric Company (PG&E).
Abstract: Results of work undertaken at the Pacific Gas and Electric Company to quantify the potential benefits of distributed grid-connected photovoltaic generation are presented. Methodologies and evaluations used to examine potential benefits of distributed generation for a test case are described. Results indicate there can be significant distributed benefits in carefully chosen transmission and distribution systems. It is concluded that these benefits could enable PV generation to be a potentially cost-effective alternative for utility planning. and thereby stimulate utility demand for PV systems. Specifically, it is demonstrated that PV power plants can relieve thermal overloads in selected utility distribution systems. Other benefits of strategically located PV systems are electrical loss savings, voltage support, and higher reliability. >

93 citations


Proceedings ArticleDOI
21 May 1990
TL;DR: In this paper, the AM 1.5 spectra provide a reference point corresponding to a particular set of atmospheric conditions and a specific air mass, and the uncertainty in using AM 1 5 spectra to predict field performance depends on the particular PV device design and climate.
Abstract: The origin of the AM 1.5 spectra, how they are related to actual outdoor spectral distributions, and the implications for outdoor PV (photovoltaic) performance predictions are explained. It is pointed out that the AM 1.5 spectra provide a reference point corresponding to a particular set of atmospheric conditions and a specific air mass. One can expect variations in outdoor PV device performance for different atmospheric conditions and air masses. The uncertainty in using AM 1.5 spectra to predict field performance depends on the particular PV device design and climate. The wavelength distribution of photon flux varies with respect to conditions such as water vapor and air mass, and this in turn influences current densities in PV devices, depending on such device characteristics as bandgap(s). Therefore, PV device design (e.g. optimization) should be based on a range of spectra representing various atmospheric conditions and air masses. >

93 citations


Patent
25 Jun 1990
TL;DR: In this article, a portable power supply having a rechargeable battery in a housing mounted on a portable frame is used for converting DC power to AC power and for recharging the battery from an external AC source.
Abstract: A portable power supply having a rechargeable battery in a housing mounted on a portable frame An inverter/converter unit, attached to the frame, is hardwired to the battery for conversion of DC power to AC power and for recharging the battery from an external AC source Power distribution means are provided for distributing DC and AC Power Photovoltaic panels are mounted to the frame for recharging the battery

90 citations


Journal ArticleDOI
TL;DR: In this paper, the performance, availability, and maintenance for ten photovoltaic plants since 1983 are reviewed and achievable capacity factors are presented. And the cost of PV electricity is developed as a function of investment cost, maintenance costs, and capacity factor, which in turn is dependent upon the site, the plant's availability and the tracking employed.
Abstract: The author reviews the performance, availability, and maintenance for ten photovoltaic plants since 1983. Problems are examined and achievable capacity factors are presented. The cost of photovoltaic electricity is developed as a function of investment cost, maintenance costs, and capacity factor, which in turn is shown to depend upon the site, the plant's availability, and the tracking employed. >

87 citations


Proceedings ArticleDOI
21 May 1990
TL;DR: A microprocessor-based solar tracking controller was designed and fabricated and is capable of acquiring photovoltaic and meteorological data from a photvoltaic system and controlling battery/load.
Abstract: A microprocessor-based solar tracking controller was designed and fabricated. In addition to tracking, the controller is capable of acquiring photovoltaic and meteorological data from a photovoltaic system and controlling battery/load. These features are extremely useful in autonomous PV power systems installed in remote areas for system control and monitoring. Solar tracking can be achieved in closed-loop and open-loop modes, and the controller can provide either six PWM (pulse-width-modulated) signals for a three-phase, 50 Hz AC motor or four step signals for a stepper motor. The controller has been laboratory tested. >

77 citations



Journal ArticleDOI
TL;DR: The early 1970s stimulated numerous investigations of semiconductor/liquid junctions for the conversion and storage of solar energy as discussed by the authors, with the potential for inexpensive, chemically based energy conversion devices, with the accompanying potential to effect the direct conversion of light into chemical fuels.
Abstract: The energy crisis of the early 1970s stimulated numerous investigations of semiconductor/liquid junctions for the conversion and storage of solar energy Although similar in concept to solid-state photovoltaic devices, semiconductor /liquid junctions offered the potential for inexpensive, chemically based energy-conversion devices, with the accompanying potential to effect the direct conversion of light into chemical fuels

74 citations


Patent
04 Sep 1990
TL;DR: In this article, a long-life, electrical energy source having an adjustable output is comprised of a light emitting phosphor activated by a radioisotope and coupled to a plurality of photovoltalic cells that have their outputs electrically connected together.
Abstract: A long-life, electrical energy source having an adjustable output is comprised of a light emitting phosphor activated by a radioisotope and coupled to a plurality of photovoltalic cells that have their outputs electrically connected together. The output power of the electrical energy source is effectively regulated by selectively changing the connections of the outputs of the photovoltaic cells in response to the progression of time.

Patent
26 Feb 1990
TL;DR: In this paper, a self-contained sun-powered electric power generating system comprising a fresnel mirror array made up of a plurality of quadrilateral mirrors individually mounted on a generally flat supporting structure with the mirrors aimed at a common point above the structure, was designed to fold into itself in the form of an elongate box for launch, maneuvering and protection.
Abstract: A photovoltaic electric power system for use in space A self contained sun powered electric power generating system comprising a fresnel mirror array made up of a plurality of quadrilateral mirrors individually mounted on a generally flat supporting structure with the mirrors aimed at a common point above the structure, a photovoltaic array positioned at the common point by a movable strut mechanism, heat exchanger means at the PV array to draw excess heat therefrom, coolant lines from the heat exchanger means running through the struts to transfer heat to heat pipes configured as flat panels at the edges of and perpendicular to the supporting structure, and positioning means attached to a separate structure to enable the system to track the sun The system is designed to fold into itself in the form of an elongate box for launch, maneuvering and protection

Journal ArticleDOI
TL;DR: In this article, the authors derived the irradiance received and the energy costs for tracking photovoltaic systems and V-trough concentrators relative to the costs of a fixed system.

Proceedings ArticleDOI
21 May 1990
TL;DR: In this paper, the authors investigate the electrical status of photovoltaic (PV) array components in mismatching conditions, leading to general rules for shaded PV array modules with bypass diodes.
Abstract: Simulation was used to investigate the electrical status of photovoltaic (PV) array components in mismatching conditions, leading to general rules for shaded PV array modules with bypass diodes. In particular, it is shown that, for a given PV array, load, and shading ratio (SR), there is a critical load point that identifies a load current (or load voltage) beyond (or below) which the diode securely goes into operation. The values of dissipated power and reverse voltage of shaded cell are lower when the diode does not go into operation. With the diode in operation the worst condition for the shaded cell occurs for minimum SR, there is a current split between diode and module, and the diode current increases with increasing SR. If the array is short circuited, the diode goes into operation with minimum SR. With the diode in operation, the electrical state of the shaded module is practically independent of array configuration. >

Journal ArticleDOI
TL;DR: In this article, the authors present a comprehensive large-signal stability analysis of a solar-array power system with a typical nonlinear load characteristic, and employ stateplane analysis techniques to characterize the dynamic behavior of the system from an arbitrary initial condition.
Abstract: The authors present a comprehensive large-signal stability analysis of a solar-array power system. The stability of the equilibrium points of a system with a typical nonlinear load characteristic is analyzed. Employing state-plane analysis techniques, the dynamic behavior of the system from an arbitrary initial condition is characterized, and the region of the desired stable operation is identified. The stability and transient response of the system operation near the solar array's maximum power point are evaluated. The dynamic response of the spacecraft power system operating in the shunt mode and battery-discharge mode is analyzed. >

Proceedings ArticleDOI
07 Oct 1990
TL;DR: In this paper, a single-phase utility interactive photovoltaic (PV) system, including the insulated-gate bipolar-transistor (IGBT) current-source pulsewidth modulation (PWM) inverter with two auxilliary IGBTs is described.
Abstract: The single-phase utility interactive photovoltaic (PV) system, including the insulated-gate bipolar-transistor (IGBT) current-source pulse-width modulation (PWM) inverter with two auxilliary IGBTs is described. The system configuration, its operation, and experimental results which include steady-state characteristics with waveforms are presented. It is shown that the system can supply a utility with maximum power corresponding to the insolation with sinusoidal current waveforms at unity power factor. The modulation index and firing angle are fixed, and there is no need for feedback control. In case of emergency, the system can be instantaneously disconnected from the utility line by turning off all the main IGBTs. Simultaneously, the two auxiliary IGBTs are turned on to let the DC current circulate through these IGBTs, the PV array, and the DC reactor. >

Proceedings ArticleDOI
21 May 1990
TL;DR: In this article, the authors present a technique for finding the irradiance levels for optimum switching of photovoltaic powered water pumping systems operating with a multistage electrical array reconfiguration controller (EARC).
Abstract: The authors present a technique for finding the irradiance levels for optimum switching of photovoltaic (PV) powered water pumping systems operating with a multistage electrical array reconfiguration controller (EARC). Depending on the starting current requirements and the irradiance levels, the EARC reconfigures a PV array to be in parallel connection at a low irradiance level and in series connection at a high irradiance level. In this way, the quality of load matching in a PV power system will be improved because at low irradiance levels the power available to the motor in parallel connection is greater than the power available in a series connection and vice versa at higher irradiance levels. Optimum switching occurs when the power output of a parallel-connected array equals the power output of a series-connected array for a given irradiance level. >

Patent
07 Sep 1990
TL;DR: In this paper, a lockup cancelling drive device is used to cancel the solar array bus lockup state by detecting the voltage of the power bus, the discharge current of the storage battery, and the load current.
Abstract: A solar cell power system includes a device which determines the occurrence of solar array bus lockup by detecting the voltage of the power bus, the discharge current of the storage battery, and the solar array current (or the load current) and performing a calculation using these items of data in addition to the regulated bus voltage to emit a lockup signal, by which the magnitude of the load is reduced, thereby cancelling the lockup state. Alternatively, a solar cell system may include a lockup cancelling drive device, which accumulates in a coil cancelling-drive, energy supplied from the storage battery and then discharges this energy to the power bus, thereby cancelling the lockup stage without reducing the magnitude of the load.

Journal ArticleDOI
TL;DR: In this paper, the authors describe the development of an inflatable concentrator for solar propulsion, providing the source of heat to a hydrogen engine aboard the Solar Rocket, a device designed to carry payloads from a low earth orbit (LEO) to a geosynchronous orbit (GEO) at significant mass savings in comparison to chemical propulsion; it involves two light-weight parabolic reflectors in an off-axis configuration focusing solar radiation into the absorbers of the engine, which causes the emission of a hot hydrogen jet.
Abstract: This paper describes the development of an inflatable concentrator for solar propulsion, providing the source of heat to a hydrogen engine aboard the Solar Rocket. The latter is a device designed to carry payloads from a low earth orbit (LEO) to a geosynchronous orbit (GEO) at significant mass savings in comparison to chemical propulsion; it involves two light-weight parabolic reflectors in an off-axis configuration focusing solar radiation into the absorbers of the engine, which causes the emission of a hot hydrogen jet. Each of the reflectors has an elliptical rim with a 40 m major axis, providing heat to the propellant sufficient to produce about 40 lbs. of thrust. The same concentrator concept is contemplated for space power application to focus solar radiation on a conversion device, e.g., a photovoltaic array or the high temperature end of a dynamic engine. Under the present project, a one-fourth scale, 9X7 m off-axis inflatable concentrator has been under development as a pilot for the full-scale flight unit. The reflector component consists of a reflective membrane made of specially designed gores and a geometrically identical transparent canopy. The two form together an inflatable lenslike structure which, upon inflation, assumes the accurate paraboloidal shape. Thismore » inflatable structure is supported along its rim by a strong, bending-resistant torus. The paper describes the development of this system including the analysis leading to determination of the gore shapes, the reflector membrane design and testing, the analysis of the supporting torus, and a discussion of the effects of the space environment.« less


Patent
03 Dec 1990
TL;DR: In this article, a system for producing and distributing electric power on a sailing ship, using arrays of photovoltaic cells covering the ships sails and rigging to generate electric power during daylight for the purpose of driving a ships screw.
Abstract: A system for producing and distributing electric power on a sailing ship, using arrays of photovoltaic cells covering the ships sails and rigging to generate electric power during daylight for the purpose of driving a ships screw. The solar array electric power output is processed by a voltage regulator which charges a large capacity storage battery and energizes an electric motor to drive the ships screw. An AC inverter is also provided to convert the DC power for the AC loads. To increase the area normally available on sailing ships for solar arrays, wing-booms which extend the lengths of the yards, and rolling booms above the yards are proposed for addition to the ships superstructure. The invention should make it possible for sailing ships to resume transportation of cargo without the need for auxiliary gas or oil-burning engines and a fuel supply.

Journal ArticleDOI
TL;DR: In this paper, a steady state model has been developed which analyses process performances, the costs of each of the stages in hydrogen production, storage and distribution, and estimates material and energy requirements for building and operating the solar hydrogen energy system.

Patent
05 Feb 1990
TL;DR: In this article, a system for the collection and conversion of solar radiated power into electrical energy is proposed. But the system is not suitable for the use of solar energy in the power grid.
Abstract: A system for the collection and conversion of solar radiated power into electrical energy The system improves present solar power conversion systems by locating key elements deep underground, thereby greatly decreasing thermal losses and increasing system efficiency to an estimated 80 percent In particular, a vertical mine shaft, at least 100 meters deep is used for transmitting collected solar flux from above ground heliostat fields, down to an insulated boiler The boiler converts injected water into superheated steam which drives a steam turbine connected to an alternator or generator producing 50 to 100 Mw electrical power Provision is made for an auxiliary drive system, using stored water or stored heat to operate the generator during hours of darkness or high load demand

Journal ArticleDOI
TL;DR: In this article, the authors examined the impact of operating PV systems on the electric utility production cost (fuel and variable operation and maintenance), the load profile of a southeastern utility and the PV output data from solar test facilities in Virginia and North Carolina are used.
Abstract: The parameters which impact the value of photovoltaics (PV) to the electric utility is examined. High, medium, and low-load days in winter (January) and summer (July) are studied. The daily peak load is varied from 5838 MW to 9712 MW. These six days are studied for reference (no PV), high, medium, low, and intermittent-PV output cases. Results from these 30 case studies are summarized. In order to study the impact of operating PV systems on the electric utility production cost (fuel and variable operation and maintenance), the load profile of a southeastern utility and the PV output data from solar test facilities in Virginia and North Carolina are used. The performance analysis shows that, while the total production (fuel and variable O&M) cost savings are higher for higher solar days, the increase is not proportional to the amount of PV energy output. It is shown that the high solar day never produced the highest per-unit PV energy value. The highest per-unit PV energy values for both winter and summer days are found to be for the low solar days. >

Proceedings ArticleDOI
11 Jun 1990
TL;DR: In this article, two separate electrical system designs for a solar-powered vehicle built for a race across Australia in November 1987 and a third system for a second race in November 1990 are described.
Abstract: Two separate electrical system designs for a solar-powered vehicle built for a race across Australia in November 1987 are described A third system for a second race in November 1990 is also described The design of motors, motor controllers, DC-DC power converters, and maximum power point trackers (MPPTs) under a specialized set of criteria is discussed >

Patent
20 Mar 1990
TL;DR: In this article, a thin, lightweight solar cell utilizes front contact metallization, where both the front light receiving surface and the facing surface of the cover glass are recessed.
Abstract: A thin, lightweight solar cell utilizes front contact metallization. Both the front light receiving surface of the solar cell and the facing surface of the cover glass are recessed to accommodate this metallization. This enables the two surfaces to meet flush for an optimum seal.

Patent
06 Dec 1990
TL;DR: In this paper, a swimming pool skimmer includes a paddle wheel that directs fluid and debris into a debris catcher, which is powered by a motor that is powered from an array of solar cells.
Abstract: A swimming pool skimmer includes a paddle wheel that directs fluid and debris into a debris catcher. The paddle wheel is turned by a motor that is powered from an array of solar cells. A solar concentrator focuses solar energy onto the solar cells, and an alarm circuit includes a strain gauge on the debris catcher. The strain gauge forms one leg of a bridge circuit that is connected to a comparator having a feedback loop. The output of the comparator is connected to an alarm element either directly or remotely.

Patent
13 Nov 1990
TL;DR: In this article, a thermoelectric module powered by a solar cell is used to cool a battery which serves as a backup power supply in a time-of-use power meter.
Abstract: A thermoelectric module powered by a solar cell is used to cool a battery which serves as a backup power supply in a time-of-use power meter. Solar irradiation incident on the power meter containing the battery, of sufficient intensity to result in heating of the battery, concurrently causes the solar cell to generate an electric current. If the battery temperature rises above a predetermined level, the thermoelectric module cools the battery in dependence on the power generated by the solar cell.

Journal ArticleDOI
TL;DR: The most recent developments in the utilization of materials in photovoltaic devices can be found in this paper, which is limited primarily to publications from 1987 through 1989, focusing on the most recent development in the development of materials for photovolastic energy conversion.
Abstract: Despite the fact that the 1980s have been a period in which public and government support for photovoltaics has been greatly underemphasized, it is heartening to realize that considerable activity in research and development of solar cells continues, as does a steady, positive experience in the field. In order to focus on the most recent developments in the utilization of materials in photovoltaic devices, this paper is limited primarily to publications from 1987 through 1989. The development of materials for photovoltaic energy conversion is a significant contribution to the development of alternative energy sources. Students of the energy question have realized for some time that traditional sources of energy (coal, oil, natural gas) supply only a limited reservoir when future energy needs of the earth are considered in terms of hundreds rather than tens of years. Recently, we have become increasingly aware of other problems associated with energy production by the combustion of fossil fuels as well: air pollution, acid rain, and the greenhouse effect, to mention only a few. In particular, the greenhouse effect is raising an increasing concern. This paper discusses the materials used for photovoltaics.

Journal ArticleDOI
TL;DR: In the last few years there have been rapid advances in thin-film solar cell technology as mentioned in this paper, and industry projections indicate that 12-18% efficient photovoltaic (PV) cells costing $0.20-0.40 per peak Watt could become available by the year 2000, and hydrogen could be produced via PV-powered electrolysis in sunny areas such as the Southwestern United States at costs of $9-14 per GJ.