Showing papers on "Electric power published in 2001"

Materials for fuel-cell technologies

Abstract: Fuel cells convert chemical energy directly into electrical energy with high efficiency and low emission of pollutants. However, before fuel-cell technology can gain a significant share of the electrical power market, important issues have to be addressed. These issues include optimal choice of fuel, and the development of alternative materials in the fuel-cell stack. Present fuel-cell prototypes often use materials selected more than 25 years ago. Commercialization aspects, including cost and durability, have revealed inadequacies in some of these materials. Here we summarize recent progress in the search and development of innovative alternative materials.

Wind Energy Handbook

Abstract: As environmental concerns have focused attention on the generation of electricity from clean and renewable sources wind energy has become the world's fastest growing energy source. The Wind Energy Handbook draws on the authors' collective industrial and academic experience to highlight the interdisciplinary nature of wind energy research and provide a comprehensive treatment of wind energy for electricity generation. Features include: * An authoritative overview of wind turbine technology and wind farm design and development * In-depth examination of the aerodynamics and performance of land-based horizontal axis wind turbines * A survey of alternative machine architectures and an introduction to the design of the key components * Description of the wind resource in terms of wind speed frequency distribution and the structure of turbulence * Coverage of site wind speed prediction techniques * Discussions of wind farm siting constraints and the assessment of environmental impact * The integration of wind farms into the electrical power system, including power quality and system stability * Functions of wind turbine controllers and design and analysis techniques With coverage ranging from practical concerns about component design to the economic importance of sustainable power sources, the Wind Energy Handbook will be an asset to engineers, turbine designers, wind energy consultants and graduate engineering students.

High-Tc superconducting materials for electric power applications.

Abstract: Large-scale superconducting electric devices for power industry depend critically on wires with high critical current densities at temperatures where cryogenic losses are tolerable This restricts choice to two high-temperature cuprate superconductors, (Bi,Pb)2Sr2Ca2Cu3Ox and YBa2Cu3Ox, and possibly to MgB2, recently discovered to superconduct at 39 K Crystal structure and material anisotropy place fundamental restrictions on their properties, especially in polycrystalline form So far, power applications have followed a largely empirical, twin-track approach of conductor development and construction of prototype devices The feasibility of superconducting power cables, magnetic energy-storage devices, transformers, fault current limiters and motors, largely using (Bi,Pb)2Sr2Ca2Cu3Ox conductor, is proven Widespread applications now depend significantly on cost-effective resolution of fundamental materials and fabrication issues, which control the production of low-cost, high-performance conductors of these remarkable compounds

The Energy Harvesting Eel: a small subsurface ocean/river power generator

Abstract: The Energy Harvesting Eel (Eel) is a new device that uses piezoelectric polymers to convert the mechanical flow energy, available in oceans and rivers, to electrical power. Eel generators make use of the regular trail of traveling vortices behind a bluff body to strain the piezoelectric elements; the resulting undulating motion resembles that of a natural eel swimming. Internal batteries are used to store the surplus energy generated by the Eel for later use by a small, unattended sensor or robot. Because of the properties of commercially available piezoelectric polymers, Eels will be relatively inexpensive and are easily scaleable in size and have the capacity to generate from milli-watts to many watts depending on system size and flow velocity of the local environment. A practical Eel structure has been developed that uses the commercially available piezoelectric polymer, PVDF. Future Eels may use more efficient electrostrictive polymer. Every aspect of the system from the interactions between the hydrodynamics of the water flow and structural elements of the Eel, through the mechanical energy input to the piezoelectric material, and finally the electric power output delivered through an optimized resonant circuit has been modeled and tested. The complete Eel system, complete with a generation and storage system, has been demonstrated in a wave tank. Future work on the Eel will focus on developing and then deploying a small, lightweight, one-watt power generation unit, initially in an estuary and then subsequently in the ocean. Such Eels will have the ability to recharge batteries or capacitors of a distributed robotic group, or remote sensor array, thus extending the mission life indefinitely in regions containing flowing water.

Design and fabrication of a new vibration-based electromechanical power generator

Abstract: A device is described for generating electrical power from mechanical energy in a vibrating environment. The design utilises an electromagnetic transducer and its operating principle is based on the relative movement of a magnet pole with respect to a coil. The approach is suitable for embedded remote microsystems structures with no physical links to the outside world. Simulation, modelling and test results following fabrication of a first prototype have demonstrated that generation of practical amounts of power within a reasonable space is possible. Power generation of more than 1 mW within a volume of 240 mm3 at a vibration frequency of 320 Hz has been obtained.

System, method and computer program product for enhancing commercial value of electrical power produced from a renewable energy power production facility

Abstract: A method, system and computer program product enhance the commercial value of electrical power produced from a wind turbine production facility. Features include the use of a premier power conversion device that provides an alternative source of power for supplementing an output power of the wind turbine generation facility when lull periods for wind speed appear. The invention includes a communications infrastructure and coordination mechanism for establishing a relationship with another power production facility such that when excess electrical power is produced by the wind turbine facility, the excess may be provided to the power grid while the other energy production facility cuts back on its output production by a corresponding amount. A tracking mechanism keeps track of the amount of potential energy that was not expended at the other facility and places this amount in a virtual energy storage account, for the benefit of the wind turbine facility. When, the wind turbine power production facility experiences a shortfall in its power production output it may make a request to the other source of electric power, and request that an increase its power output on behalf of the wind turbine facility. This substitution of one power production facility for another is referred to herein as a virtual energy storage mechanism. Furthermore, another feature of the present invention is the use of a renewal power exchange mechanism that creates a market for trading renewable units of power, which have been converted into “premier power” and/or “guaranteed” by secondary sources of power source to provide a reliable source of power to the power grid as required by contract.

Towards a piezoelectric vibration-powered microgenerator

Abstract: As MEMS and Smart Material technologies advance, embedded and remote applications are becoming more widespread. Powering these systems can be a significant engineering problem, as traditional solutions such as batteries are not always appropriate. An inertial generator is developed that uses thick-film piezoelectric technologies to produce electrical power from vibrations in the environment of the device. The device validates the concept, and produces an output of 3uW. Predictions show that orders of magnitude increase in power output are possible.

Vehicle-to-Grid Power: Battery, Hybrid, and Fuel Cell Vehicles as Resources for Distributed Electric Power in California

Abstract: Electric-drive vehicles can become and important resource for the California electric utility system, with consequent air pollution, system reliability, and economic benefits. We refer to electric power resources from vehicles as “Vehicle to Grid” power (V2G). The economic value of some forms of V2G appear high, more than enough to offset the initially higher costs of electric-drive vehicles, thus having the potential to accelerate their introduction. To realize this potential, some coordination of vehicle and infrastructure planning will be needed. This study calculates three parameters of electric drive vehicles (EDVs) which are important for their use by the electric system: resources size, availability, and economic potential.

General supervisory control policy for the energy optimization of charge-sustaining hybrid electric vehicles

Abstract: A general formulation of the instantaneous power split strategy between an IC engine and an electric machine in a charge-sustaining hybrid-electric vehicle is given. It is based on the instantaneous optimization of an equivalent fuel consumption. This approach involves a heuristic formulation to convert the electrical power flow into equivalent fuel cost based on the average “cost” of electricity through the various power paths (present and future). This control strategy was implemented on a HEV prototype and real-world results are presented here, demonstrating that this approach provides excellent fuel efficiency along with robustness and charge sustaining operation. Then, a general and scalable formulation of this control strategy is proposed.

Control system for hybrid vehicle

Abstract: A control system for a hybrid vehicle has a consumed electric power calculator (20), which calculates electric power consumption, and a battery state calculator (21), which calculates battery state SOC of a battery (5). Based on this battery state, a physical quantity per effective electric power calculator (25) calculates a physical quantity per effective power when electric power equal to or greater than consumed electric power is generated for various electric power consumption and electric power generation, and a threshold value calculator (22) obtains a threshold value having the same unit as that of the physical quantity per effective power using predetermined calculation for selecting operating modes of a generator and the battery. An operating mode selector (23) selects operating modes for an engine (1) and the battery (5) based on comparison between the above threshold value and the physical quantity per effective power corresponding to the consumed electric power, and a target generated electric power calculator (24) calculates target electric power generation. An electric power distribution controller (6) controls the engine (1) and the motor (3).

Control apparatus for hybrid vehicle

Abstract: A hybrid vehicle includes a control apparatus having an engine controller and a motor controller A first battery and a second battery which has higher voltage than the first battery are provided An electric power generator which is driven by the engine is provided for charging the first battery The second battery and the electric motor are connected through the motor controller, and the first battery or the electric power generator is connected to the motor controller and the engine controller In addition, the first battery or the electric power generator is connected to the engine controller for maintaining a power supply for operation maintenance of the engine controller The second battery and the electric motor are connected through the motor controller The second battery or the electric motor is connected to the motor controller through a DC/DC converter As a result, even if the high voltage line including the electric motor in the control apparatus for the hybrid vehicle has failed, this system can drive the vehicle

Global electric power reform, privatization and liberalization of the electric power industry in developing countries

Abstract: In many developing countries, and in particular those in Asia, the Middle East, and Africa, reform of the power sector starts from a market structure that is dominated by a state-owned national power utility with a legally endowed monopoly and a vertically integrated supply chain encompassing power generation, transmission, distribution, and customer services. The rationale for this structure is minimization of the costs of coordination between these functions and of financing the development of power systems. The pre-reform structure in other countries, notably in South America, places distribution and customer services with local companies, separate from national companies that provide power generation and transmission. Power reforms are designed to introduce competition where feasible, which is in the upstream production and downstream supply functions of the industry structure, and to use economic regulation of the wholesale and retail power markets to promote competition and protect consumer interests. Regulation of the power market is essential, as shown by the experience of New Zealand, which tried an approach without the amount of regulation used elsewhere. Their approach was based on mandatory separation of generation, transmission, and distribution, using general competition laws to deal with both the terms of interconnection and conduct generally in unbundled power networks.

Vehicle-to-Grid Power: Battery, Hybrid, and Fuel Cell Vehicles as Resources for Distributed Electric Power in California

Abstract: Electric-drive vehicles can become and important resource for the California electric utility system, with consequent air pollution, system reliability, and economic benefits. We refer to electric power resources from vehicles as “Vehicle to Grid†power (V2G). The economic value of some forms of V2G appear high, more than enough to offset the initially higher costs of electric-drive vehicles, thus having the potential to accelerate their introduction. To realize this potential, some coordination of vehicle and infrastructure planning will be needed. This study calculates three parameters of electric drive vehicles (EDVs) which are important for their use by the electric system: resources size, availability, and economic potential.

A self-powered mechanical strain energy sensor

Abstract: With the growing use of sensors in various structural and mechanical systems, the powering and communication of these sensors will become a critical factor. Wireless communication electronics are becoming ubiquitous and with the decreasing electrical power requirements for these circuits it is now feasible to generate power from the conversion of mechanical energy into electrical energy. This paper focuses on the theoretical and experimental analysis of a simple mechanical strain energy sensor with wireless communication. A simple beam bending experiment is given to illustrate some of the characteristics of the self-powered strain energy sensor.

Methods and apparatus for controlling electric appliances during reduced power conditions

Abstract: An electric power monitoring system includes a source monitor for measuring momentary power output of an electric source supplying electric power to a power distribution system having at least one electric load. The momentary power output is compared with a reference load capability for the electric source to determine the ability of the electric source to support additional load, and load capability data is transmitted based on the load capability. At least one load control receives the transmitted load capability data and controls the supply of power to the at least one corresponding electric load based on the load capability data.

Vehicle information communication system and method capable of communicating with external management station

Abstract: In a vehicle diagnosis information communication system, electric power is supplied from a battery to a vehicle control computer mounted on the vehicle during a period of vehicle operation, while the electric power is supplied to a radio communication unit mounted on the vehicle irrespective of the vehicle operation. The computer transmits a vehicle information such as engine diagnosis result to the radio communication unit through a communication line. The radio communication unit communicates the received vehicle information to an external site of communication in response to a request of the information form the external site of communication irrespective of the supply of the electric power to the computer. Preferably, the supply of the electric power from the battery to the computer is maintained for a predetermined period after the vehicle operation.

System, method, rotating machine and computer program product for enhancing electric power produced by renewable facilities

Abstract: An electric power system provides a coordinated and controlled intercommunication and operation of power engineering equipment and converters, e.g., rotating AC machines, power electronic converters and transformers as well as power grids in order to enhance electric power produced by renewable facilities. As viewed from the power grid and its stakeholders' perspective, enhanced renewable facilities are more stiff than conventional renewable facilities, and produce power that is as commercially valuable and fungible as electric power produced by traditional plants such as fossil fuel power plants, hydroelectric plants, nuclear plants and the like. xMs and SMs, or more generally yMs, fulfill the demands of stiffness and reduced variability, which have conventionally limited the commercial usefulness of a large scale use of renewables delivering power to a power grid.

Electrical motor power management system

Abstract: A power control system for an electric traction motor in a vehicle comprising at least one inverter for providing conditioned electrical power to the electric traction motor, a plurality of power stages for providing DC power to the at least one inverter, each stage including a battery and boost/buck DC-DC converter, the power stages wired in parallel, and where the power stages are controlled to maintain an output voltage to the at least one inverter.

Oil well casting electrical power pick-off points

Abstract: A power supply apparatus is provided for supplying power and communications within a first piping structure. An external power transfer device is positioned around the first piping structure and is magnetically coupled to an internal power transfer device. The internal power transfer device is positioned around a second piping structure disposed within the first piping structure. A main surface current flowing on the first piping structure induces a first surface current within the external power transfer device. The first surface current causes a second surface current to be induced within the internal power transfer device.

Hybrid vehicle and method of controlling hybrid vehicle

Abstract: In a hybrid vehicle of the present invention, an engine EG is subjected to feedback control to attain a target revolving speed NE*. In the case of malfunction of an inverter P 1 for a generator GN, operation of the inverter P 1 is stopped. When the generator GN is driven to rotate at a predetermined rotational speed, a counter electromotive force arises in a multiphase phase coil of the generator GN. When a motor MG is connected to the generator GN as a loading, electric current runs via a protection diode of the inverter P 1 to implement power generation by the generator GN. The electric power generated by the generator GN is directly consumed by the motor MG. This arrangement enables the quantity of power generation to balance the quantity of consumption. Here the revolving speed of the engine EG is varied according to the loading applied to the vehicle. The arrangement of the present invention thus enables the amount of electric power generated by one of the generator GN and the motor MG to balance the amount of electric power consumed by the other of the generator GN and the motor MG, thus attaining a drive of the hybrid vehicle without using a secondary battery.

System for wirelessly supplying a large number of actuators of a machine with electrical power

Abstract: A configuration for supplying a large number of actuators with electrical power without using wires includes at least one primary winding that is fed from a medium-frequency oscillator. Each actuator has at least one secondary winding that is suitable for drawing power from a medium-frequency magnetic field.

Impact of renewable distributed generation on power systems

Abstract: The traditional approach in electric power generation is to have centralized plants distributing electricity through an extensive transmission & distribution network. Distributed generation (DG) provides electric power at a site closer to the customer, eliminating the unnecessary transmission and distribution costs. In addition, it can reduce fossil fuel emissions, defer capital cost, reduce maintenance investments and improve the distribution feeder voltage conditions. In the case of small residential photovoltaic (PV) and wind systems, the actual generator locations and DG penetration level are usually not apriori known. The following study attempts to calculate the boundaries of the impact of randomly placed distributed generators on a distribution feeder. Monte Carlo simulations are performed, and boundaries for overall improvements are determined. The study shows that the knowledge of total penetration of small PV systems is sufficient to estimate the effects of DG on the feeder.

Solar Power Tower Design Basis Document, Revision 0

Abstract: This report contains the design basis for a generic molten-salt solar power tower. A solar power tower uses a field of tracking mirrors (heliostats) that redirect sunlight on to a centrally located receiver mounted on top a tower, which absorbs the concentrated sunlight. Molten nitrate salt, pumped from a tank at ground level, absorbs the sunlight, heating it up to 565 C. The heated salt flows back to ground level into another tank where it is stored, then pumped through a steam generator to produce steam and make electricity. This report establishes a set of criteria upon which the next generation of solar power towers will be designed. The report contains detailed criteria for each of the major systems: Collector System, Receiver System, Thermal Storage System, Steam Generator System, Master Control System, and Electric Heat Tracing System. The Electric Power Generation System and Balance of Plant discussions are limited to interface requirements. This design basis builds on the extensive experience gained from the Solar Two project and includes potential design innovations that will improve reliability and lower technical risk. This design basis document is a living document and contains several areas that require trade-studies and design analysis to fully complete the design basis. Project- and site-specific conditions and requirements will also resolve open To Be Determined issues.

Hybrid energy locomotive electrical power storage system

Abstract: A hybrid energy locomotive system having an energy storage and regeneration system. In one form, the system can be retrofitted into existing locomotives, or installed as original equipment. The energy storage and regeneration system captures dynamic braking energy, excess motor energy, and externally supplied energy and stores the captured energy in one or more energy storage subsystems, including a flywheel, a battery, an ultra-capacitor, or a combination of such subsystems. The energy storage and regeneration system can be located in a separate energy tender vehicle. The separate energy tender vehicle is optionally equipped with traction motors. An energy management system is responsive to power storage and power transfer parameters, including data indicative of present and future track profile information, to determine present and future electrical energy storage and supply requirements. The energy management system controls the storage and regeneration of energy accordingly.

Turbogenerator power control system

Abstract: A power control system for a turbogenerator which provides electrical power to one or more pump-jack oil wells. When the induction motor of a pump-jack oil well is powered by three-phase utility power, the speed of the pump-jack shaft varies only slightly over the pumping cycle but the utility power requirements can vary by four times the average pumping power. This power variation makes it impractical to power a pump-jack oil well with a stand-alone turbogenerator controlled by a conventional power control system. This power control system comprises a turbogenerator inverter, a load inverter, and a central processing unit which controls the frequency and voltage/current of each inverter. Throughout the oil well's pumping cycle, the central processing unit increases or decreases the frequency of the load inverter in order to axially accelerate and decelerate the masses of the down hole steel pump rods and oil, and to rotationally accelerate and decelerate the masses of the motor rotors and counter balance weights. This allows kinetic energy to be alternately stored in and extracted from the moving masses of the oil well and allows the oil pumping power to be precisely controlled. Historical data on the load inverter's frequency versus time profile throughout previous pumping cycles, which resulted in nearly constant turbogenerator power requirements, is utilized to further reduce variations in power.

Mobile power generation system

Abstract: A power generation system is described for supplying electrical power to a load (128) from at least one of a generator (108) and a battery (110). The power generation system includes a power bus (116) coupled to the generator and a bidirectional conversion unit (106) coupled between the power bus and the battery. The bidirectional conversion unit is capable of transitioning between a first direction wherein electrical power flows from the power bus to the battery and a second direction wherein electrical power flows from the battery to the power bus.

Apparatus for the production of freshwater from extremely hot and humid air

Abstract: Systems and methods are disclosed for extraction of freshwater from ambient air in regions of extremely hot and humid climates, for supply of drinking water and freshwater for small to large groups of people in remote and isolated areas or wherever freshwater resources are not conveniently accessible. Compact mobile units are disclosed to provide freshwater and drinking water for resort areas, to passengers on land and sea vehicles, in situations of emergency, and to areas of water shortage. The art of adaptation of commercial dehumidification units is taught in design and construction of apparatus for production of freshwater and drinking water. Preparation of drinking water included ultraviolet disinfection, ozone treatment, and/or chlorine addition; activated carbon and ion exchange filters; and adding of fluorine, air/oxygen to refresh the water storage units, and minerals for taste and health provisions. For energy economy and use of independent electric power supply, the produced water may flow under gravitational forces entirely or with the assistance of small boasting pumps. Lukewarm, hot, cold, and/or cold carbonated drinking water are provided as well as freshwater for other usage.