Showing papers on "Solar power published in 1997"

Unit sizing and control of hybrid wind-solar power systems

Abstract: The aim of this paper is to provide the core of a CAD/CAA tool that can help designers determine the optimal design of a hybrid wind-solar power system for either autonomous or grid-linked applications. The proposed analysis employs linear programming techniques to minimize the average production cost of electricity while meeting the load requirements in a reliable manner, and takes environmental factors into consideration both in the design and operation phases. While in autonomous systems, the environmental credit gained as compared to diesel alternatives can be obtained through direct optimization, in grid-linked systems emission is another variable to be minimized such that the use of renewable energy can be justified. A controller that monitors the operation of the autonomous/grid-linked systems is designed. Such a controller determines the energy available from each of the system components and the environmental credit of the system. It then gives details related to cost, unmet and spilled energies, and battery charge and discharge losses.

Scavenger energy converter system its new applications and its control systems

Abstract: What has been invented is a series of scientific applications of the wideface energy converter device, be it in the form of a wideface solar heat receiver or a wideface fluid impeder device. The wider is the solar heat receiver, the more solar power is available for conversion. The wider is the sail of the boat, the more wind is available to push the boat. Wherefore, the wideface solar trap made up of multi-layer transparent roofs covering a heat insulated box is used to heat up a radiator tubings that contain water. The multilayer transparent roof, having spaces in between sheets, prevents solar heat from backing out hence the trap becomes hoter and hoter because the inner sheet is not in contact with the cold wind. This solar trap is now used to heat up radiator pipes of compressed air coming from a gas turbine engine and then returned back to the exhaust turbine of same engine. Applying the principle of the wind sail, the turbine blades of the compressor and the turbine blades of the exhaust turbine are made wideface as much as possible to produce maximum impedance against the expanding exhaust hot air and to produce maximum push upon the fresh air being compressed. This wideface fluid impeder is now expanded into an underwater platform from One Acre or much more and attached to floating hotels, large/small boats, and floating sea walls, to prevent oscillation by the surfs.

Power control apparatus for solar power generation system

Abstract: In a power control apparatus of a solar power generation system for converting power generated by a solar panel and supplying the converted power to a load, the output voltage and output current of the solar panel are sensed, and, under ordinary conditions, MPPT control is performed so that the solar cells will operate at a maximum output point. If the output power of the solar panel exceeds a predetermined power, a power conversion unit is controlled so as to raise the output voltage of the solar panel, thereby limiting the output power of the solar panel. As a result, excessive power is prevented from being output by the power control apparatus.

Solar power generation apparatus and power control device therefor

Abstract: In order to extract maximum power from a solar cell, maximum power point tracking (MPPT) control is performed under ordinary circumstances. If the output current of the solar cell becomes too small, the operating point of the solar cell is caused to fluctuate over a range wider than that of MPPT control at a period longer than that of MPPT control and the output voltage and current of the solar cell is sampled. In a case where it is indicated by power values obtained from the sample voltage values and current values that a plurality of maximal points of power value exist, a voltage value corresponding to a power value indicative of the largest value is set as the operating point of the solar cell.

Photovoltaic Conversion of Concentrated Sunlight

Abstract: The potential of solar power as a viable source of renewable energy has been expanded by the recent achievements in sunlight concentration techniques described in this book, which provides a comprehensive treatment of the issues involved in this new efficient and cost-effective sustainable power resource. Fabrication problems for terrestrial and space photovoltaic installations and ohmic losses in solar cells are discussed, as are the semiconductor physics underlying photovoltaics. Concentrator solar cell structures and performance are noted. The book closes with a discussion on the optimization of solar photovoltaic power plants with concentrators. (UK)

Control of DC/DC converters for solar energy system with maximum power tracking

Abstract: Solar power converters were used to convert the electrical energy from solar arrays to a stable and reliable power source. The object of this paper is to analyze and design DC/DC power converters of different types in a PV power system to investigate the performance of such converters. A simple method which combines discrete time control and a PI compensator is used to track the maximum power points (MPPs) of the solar array. The system is kept to operate close to the MPPs, thus the maximum possible power transfer from the solar array is achieved. The implementation of the proposed power converter system was based on a digital signal processor. Experimental tests were carried out for buck, boost and buck-boost power converters using a simple maximum power point tracking algorithm. The efficiencies for the system with different power converters are compared and presented.

Bifacial lightweight array for solar power

Abstract: A laminate includes bifacial solar cells that can receive and convert sunlight incident from either side. The laminate is held in a frame by high tensile cords that are strung like the cords in a tennis racket. The resulting assembly receives direct sunlight from one side and light reflected through albedo through the other side.

Standard Handbook of Powerplant Engineering

Abstract: Section I: Energy Resources for Power Generation. Overview of U. S. Energy Resources. Coal. Oil and Natural Gas. Nuclear Energy. Hydroelectric Energy. Solar Energy. Geothermal Energy. Wind Energy. Biomass Energy. Waste Fuels. Section II: Steam Powerplants. Steam Fundamentals. Basic Powerplant Design. Steam Generators. Boiler Auxiliaries. Cooling Towers and Air-Cooled Condensers. Water Treatment. Section III: Prime Movers. Steam-Turbine Fundamentals. Steam-Turbine Design. Gas-Turbine Fundamentals. Gas-Turbine Design. Hydraulic Turbines. Oil- and Gas-Fired Reciprocating Engines. Section IV: Plant Electric Systems. AC Generators and Generator Protection. Transformers and Transformer Protection. Electrical Interconnections. In-Plant Electrical Distribution. AC Motors and Their Applications. Busway Applications. Cable Applications. Section V: Instrumentation and Control. Powerplant Instruments. Combustion Control and Burner Management. Turbine and Engine Governors. Key Systems and Components. Human Engineering: Human-Machine Interface. Section VI: Nuclear Plant Systems. Introduction. Fission Theory. Nuclear Steam Supply Systems. Nuclear Plant Operation, Maintenance, and Control. Reactor Safety. Regulation. Section VII: Hydroelectric Power Stations. General Features of a Hydroelectric Project. Dams, Spillways, Water Conductors, and Powerhouses. Auxiliary Mechanical Equipment. Hydroelectric Generators, Transformers, and Controls. Section VIII: Alternative Energy Plants--Emerging Technologies. Solar Power Systems in Space. Geothermal Power Systems. Wind Energy Technology. Wood/Biomass Powerplants. Waste-Fired Plant Design. Fuel Cell Plants. Section IX: Environmental Controls. Environmental Legisation and Regulation. Air Emission Controls. Water Emission Controls. Solid Waste Management. Powerplant Noise and Its Control. Section X: Appendices: Conversion Factors. Standard Nominal System Voltages and Voltage Ranges. Abbreviations.

Inverter apparatus and solar power generation apparatus

Abstract: In order to provide an inverter apparatus and a solar power generation apparatus in which when a main AC power system (5) has suffered, e.g., a power failure, the operation mode of an inverter (2) in the tie operation with the main AC power system (5) can be easily and safely switched from the tie operation mode to the self-support operation mode, and electric power can be supplied to a load (4) directly using normal indoor wiring, the open/closed state of a switch (3) for opening/closing a connection between the output terminal of the inverter (2) and the main AC power system (5) is detected, and the self-support operation of the inverter (2) is started when the open state of the switch (3) is detected.

Hybrid power generation system

Abstract: PROBLEM TO BE SOLVED: To obtain a hybrid power generation system combining a wind power generator, a solar power generator and an engine generator in which the stability of power system is sustained for generated power and variation of load SOLUTION: A power system 1 is connected with a wind power generator 3, a generator 7 being driven through an engine 6, and a secondary battery 8 through a reversible converter 9 Frequency of the power system 1 is detected by a detection means 11 A controller 10 receives the detection value and controls charge/discharge of the secondary battery 8 through the reversible converter 9 Furthermore, charge/discharge of the secondary battery 8 is detected through a shunt resistor 13 and inputted to an engine controller 14 for controlling the generator 7 through a governor setter 15

Solar power generator for mounting on vehicle roof and including adaptive voltage converter e.g. for driving fan motor

Abstract: A solar power generator has an arrangement of solar cells and an adaptive converter to match the current or the voltage from the cells to the load. The converter (4) is integrated with the cell arrangement(1). This arrangement is a single cell or four cells. The base material for the cell(s) is silicon. The converter has two semiconductors, part being directly in the base of the cells on the front or back. Logic building blocks are integrated into part of the cell arrangement, as is a mask-programmed microprocessor. The cell arrangement has an optical display of cell status using LED chips

Floating deep water power station extracts energy from wind, wave, water and solar sources

Abstract: The deep water esp. floating combined power station and manufacturing facility generates energy from renewable power sources which are stored within the assembly and consumed as required. The power station extracts the power from two or more renewable energy sources in the immediate vicinity of the installation e.g. differential sea water temperature, wave power, wind power or solar power, depending upon the nature of the natural energy resources present. The power extracted is used to drive one or more industrial processes either within or in the immediate vicinity of the installation. A group of such power stations may drive one or more such processes. The power station is either installed on a floating artificial island or a natural island. The floating power station has an anchorage system whose position may be varied around the artificial island, and which may be rapidly raised or lowered. The power station artificial island is mobile either in combination with a tug, or under its own power.

Solar thermophotovoltaic power conversion method and apparatus

Abstract: Solar power is concentrated onto an absorptive surface of a body to heat the body to thus result in infrared emissions. The wavelength spectrum of the infrared emissions is tailored to match the optimal incident wavelength spectrum of photovoltaic cells. This tailoring is accomplished by use of an infrared filter and/or a coating material on an emissions surface of the body. The photovoltaic cells, constructed to match the radiation spectrum of the infrared emissions, convert the infrared emissions to electric energy.

Solar box cookers: Towards a decentralized sustainable energy strategy for sub-Saharan Africa

Abstract: The continued economic decline of sub-Saharan Africa, and the African energy crisis in particular, have received considerable attention in recent literature. Little attention, however, has been given to the assessment of solar power as an environmentally sound and economically viable energy strategy. Considering the increasing fuelwood scarcity and debt incurred through petroleum imports, solar energy provides a welcome alternative to traditional biomass and fossil fuel energy sources. Research and development in solar energy has concentrated primarily on highly technical, capital intensive applications, leaving possibilities for small scale utilizations unexplored. This paper argues for small scale, decentralized development of solar power as a sustainable household fuel source for sub-Saharan Africa. Domestic cooking constitutes more than 60% of total energy use in the region and consumes scarce time, labor, income, and natural resources. Thus, the appropriate management of fuel and energy resources in the residential sector is crucial for significant development. This paper examines the economic viability of solar box cookers (SBCs), their costs and benefits both on the household and community levels, and how they may contribute to economic development. In arguing for the implementation of SBCs, policy implications in terms of financing and a comprehensive energy plan geared towards sustainable development are also presented.

Solar power generating system

Abstract: PROBLEM TO BE SOLVED: To always secure a predetermined quantity of charging with a high conversion efficiency of an inverter, by controlling the discharge of a battery unit in such a manner that the input power from a solar battery module or battery unit to the inverter always exceeds a predetermined value during inverter operation. SOLUTION: A solar battery module 1 is connected to a discharge controller 4 through a connection box 6, an inverter 3 and a battery unit 2 are connected to the discharge controller 4, and the inverter 3 is connected to a power distribution panel 7. A commercial system line 8, a load 9 and a charging controller 5 are connected to the power distribution panel 7, and this charging controller 5 is connected to a battery device 2. The discharging controller 4 starts the discharge from the battery device 2 at the same time with the start of generation of the solar cell module 1. The battery device 2 is controlled in such a manner that the discharge is continued at a constant output until the time set depending on the place and season. Thus, the shortage of charging power of the battery device can be solved.

Optimal driving strategy for a solar car on a level road

Abstract: Every three years, solar cars from all over the world come to Australia to participate in the World Solar Challenge. In 1993 there were 52 cars in the race. Five cars finished within five days, each one breaking the previous race record and achieving an average speed exceeding 70 km/h. The performance of these cars depends on many factors: power, aerodynamics, traction efficiency, weight, reliability, and (not least of all) driving strategy. On a level road, the optimal driving strategy for an ideal car is essentially a speed-holding strategy. For a real car with inefficient energy storage, however, there are two distinct holding speeds. The lower speed is held when solar power is low and must be supplemented from stored energy. The upper speed is held when solar poler is high, and excess energy is stored.

Tracking type solar power generating device and sunshine tracking device

Abstract: PROBLEM TO BE SOLVED: To provide the tracking type solar power generating device which can simplify the constitution of the sunshine tracking device which perfoms two-directional tracking of the azimuth angle and elevation angle of the sun by utilizing the heat generated by irradiating a heat reception plate with the sunshine and the sunshine tracking device. SOLUTION: As the sunshine tracking device which performs control so that the solar power generating device 30 is always irradiated with the sunshine converged by a sunshine converging device, a shape memory spring 40 is used which is thermally connected to the heat reception plate 70 heated with the converged sunshine and mechanically connected to the sunshine converging device or solar power generating device 30 and deforms mechanically and when the heat reception plate 70 is heated, the shape memory spring 40 rises in temperature and deforms owing to the temperature rise to adjust the positions or angles of the sunshine converging device and solar power generating device 30, thereby performing the control so that the solar power generating device 30 is always irradiated with the converged sunshine.

A new microcontroller based solar energy conversion modular unit

Abstract: This paper presents the design and the implementation of a new microcontroller-based solar energy conversion modular unit. The unit consists of an array of solar panels, a step-up chopper, a single-phase inverter, an AC mains power source and a microcontroller-based control unit. The novelty of this unit is that the switching device of the chopper is not only used for power conversion but also for maximum power point (MPP) detection. In existing MPP trackers, the MPP is detected by hardware. The parameters of such hardware are subject to changes of environmental conditions. In the new unit, the MPP is determined by a simple embedded software. With this new approach the modularization of the conversion from solar power to electric power at its maximum power point can be made more compact and more reliable.

Solar power generation and charging system

Abstract: PROBLEM TO BE SOLVED: To provide a system, in which a secondary battery is charged stably in a mass-production manner by a method wherein sunlight is used to the full when it can be used and a commercial power supply is used, when the sunlight cannot be used. SOLUTION: A system is provided with a solar cell 8, with a DC-DC converter 33, by which a voltage generated by the solar cell 8 is converted into a prescribed voltage, with an AC-DC converter 22 through which the AC voltage of a commercial power supply 1 is converted into a DC voltage, with a secondary battery 9 for power failure, with a secondary-battery charger 23 by which the secondary battery 9 is charged, with a changeover control circuit 21 through which the solar cell 8 is connected to the secondary-battery charger 23 when the solar cell 8 generates power and by which the AC-DC converter 22 is connected to the secondary-battery charger 23, when the solar cell 8 does not generate power and with an inverter 10 with which the DC power of the secondary battery 9 for power failure is converted into the AC voltage of the commercial power supply 1 in the power failure of the commercial power supply 1.

Environment adjusting facility

Abstract: PROBLEM TO BE SOLVED: To provide environment adjusting facilities which makes efficient use of utilities on the whole, minimizes external utility introduction, and can perform independent plant cultivation in a desert, a remote island, etc., and adjust the environment of a housing space. SOLUTION: This facilities are equipped with a thermostatic chamber 2, a solar power generating device 1, and feed water facilities (pump 51). Then the solar power generating device 1 has a solar battery 11 arranged above the thermostatic chamber 2, a jacket type permeation vaporizing film 12 is fitted onto the reverse surface of the solar battery 11, and cooling water is supplied to the gap 13 between the solar battery 11 and permeation vaporizing film 12; and vapor 62 of the cooling water permeates the permeation vaporizing film 12 and is discharged into the thermostatic chamber 2, and the solar battery 11 is cooled by using the sensible heat of the cooling water and latent heat generated when the cooling water vaporizes. The feed water facilities obtain driving electric power from the solar power generating device 11 and supplies the cooling water to the gap between the solar battery 11 and permeation vaporizing film 12.

Solar power generating equipment

Abstract: PROBLEM TO BE SOLVED: To make the maintenance and inspection of a solar cell panel having a lowered power generating efficiency by identifying and indicating a solar cell unit after a solar cell unit not reaching a predetermined level was judged to be a solar cell unit requiring maintenance and inspection SOLUTION: A solar cell panel (SP) 1 is divided by a unit A multiple cable 3 contains m×n output, detection line 3b for detecting the output for each unit, of SP1 A microcomputer 11 calculates a correction factor to be used when determining a predetermined level value for judging whether the power generating efficiency of SP1 divided for each unit has been lowered And the predetermined level value is compared to the generated power output of SP1 for each unit, solar cell panels for each unit where the generating efficiency has been lowered are accurately identified, and identification indicating for the SP1 of the unit address number for each unit, where the generating efficiency has dropped, is shown on a CRT display 14

Solar power generation system

Abstract: PROBLEM TO BE SOLVED: To obtain a solar power generation system in which the mounting method of a plurality of auxiliary solar cells is optimized and in which the influence of the shadow of the sun due to a partial cloud, the shade of a of a tree or the like is reduced as far as possible, by a method wherein the plurality of auxiliary solar cells are installed additionally and the in solution condition of a main solar cell is grasped precisely. SOLUTION: A solar cell array 1 is composed of a main solar cell 11 in which modules are arranged and of a first auxiliary solar cell 12 and a second auxiliary solar cell 13 which are installed for control use. Since the first auxiliary solar cell 12 and the second auxiliary solar cell 13 are arranged symmetrically with respect to the central axis of the solar cell array 1, the output voltage of the first auxiliary solar cell 12 and that of the second auxiliary solar cell 13 generate a large difference according to intensity of insolution. The output values are inputted to a voltage instruction device 2, and the two values are compared by the voltage instruction device 2 so as to read an absolute value. In the case of this condition, the output voltage may be judged according to a larger output voltage. When a solar power generation system is controlled by using the mean value of the two output values, its accuracy becomes better than in the case in which one out of the two output values is used.