Author:
Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 1102

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Author: National Aeronautics and Space Adm Nasa
Publisher: Independently Published
ISBN: 9781724093813
Category : Science
Languages : en
Pages : 28

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Space Flight hardware requires high power conversion efficiencies due to limited power availability and weight penalties of cooling systems. The International Space Station (ISS) Electric Power System (EPS) DC-DC Converter Unit (DDCU) power converter is no exception. This paper explores the design methods and tradeoffs that were utilized to accomplish high efficiency in the DDCU. An isolating DC to DC converter was selected for the ISS power system because of requirements for separate primary and secondary grounds and for a well-regulated secondary output voltage derived from a widely varying input voltage. A flyback-current-fed push-pull topology or improved Weinberg circuit was chosen for this converter because of its potential for high efficiency and reliability. To enhance efficiency, a non-dissipative snubber circuit for the very-low-Rds-on Field Effect Transistors (FETs) was utilized, redistributing the energy that could be wasted during the switching cycle of the power FETs. A unique, low-impedance connection system was utilized to improve contact resistance over a bolted connection. For improved consistency in performance and to lower internal wiring inductance and losses a planar bus system is employed. All of these choices contributed to the design of a 6.25 KW regulated dc to dc converter that is 95 percent efficient. The methodology used in the design of this DC to DC Converter Unit may be directly applicable to other systems that require a conservative approach to efficient power conversion and distribution. Bruemmer, Joel E. and Williams, Fitch R. and Schmitz, Gregory V. Glenn Research Center NASA/TM-2002-211804, E-13499, NAS 1.15:211804, IECEC-2002-20032...

Author: National Aeronautics and Space Adm Nasa
Publisher: Independently Published
ISBN: 9781724089847
Category : Science
Languages : en
Pages : 26

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A flywheel system and its operator interface are described. Measurements of magnetic bearing negative stiffness are performed. Two digital magnetic bearing control algorithms (PD and estimator based) are defined and their implementations are described. Tuning of each controller is discussed. Comparison of the two controllers' stability, damping noise, and operating current are described. Results describing the superiority of the estimator-based controller are presented and discussed. Dever, Timothy P. and Brown, Gerald V. and Jansen, Ralph H. Glenn Research Center NASA/TM-2002-211795, NAS 1.15:211795, IECEC-2002-20161, E-13490

Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781721804566
Category :
Languages : en
Pages : 34

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This paper describes a modeling effort used to develop an improved type of magnetic bearing controller, called a modal controller, for use on high speed flywheel systems. The controller design is based on models of the flywheel system, is designed to directly control the natural dynamics of the spinning rotor, and is generic enough to be readily adapted to future flywheel systems. Modeling and development are described for two key controller subsystems: the modal controller subsystem, which allows direct control over the rotor rigid body modes, and the bending mode compensation subsystem, which tracks, and prevents interference from, the rotor bending modes during flywheel operation. Integration of modeling results into the final controller is described and data taken on the NASA Glenn D1 flywheel module during high speed operation are presented and discussed. The improved modal controller described in this paper has been successfully developed and implemented and has been used for regular hands-free operation of the D1 flywheel module up to its maximum operating speed of 60,000 RPM. Dever, Timothy P. and Brown, Gerald V. and Duffy, Kirsten P. and Jansen, Ralph H. Glenn Research Center NASA/TM-2005-213877, E-15248, AIAA Paper 2004-5626

Author: Seth Sanders
Publisher:
ISBN:
Category : Electric power systems
Languages : en
Pages : 26

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Author: G. Genta
Publisher: Butterworth-Heinemann
ISBN: 1483101592
Category : Technology & Engineering
Languages : en
Pages : 381

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Kinetic Energy Storage: Theory and Practice of Advanced Flywheel Systems focuses on the use of flywheel systems in storing energy. The book first gives an introduction to the use of flywheels, including prehistory to the Roman civilization, Christian era to the industrial revolution, and middle of the 19th century to 1960. The text then examines the application of flywheel energy storage systems. Basic parameters and definitions, advantages and disadvantages, economic considerations, road vehicle applications, and applications for fixed machines are considered. The book also evaluates the flywheel, including materials, radial bar and filament flywheel, composite material disc flywheel, rotor stress analysis, and flywheel testing. The text also discusses housing and vacuum systems and flywheel suspension and transmission systems. Aerodynamic drag on wheels, burst containment, types of bearings, rotor dynamics, dampers, and types of transmissions are described. The text is a vital source of information for readers wanting to explore the composition and functions of flywheels.

Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781725875432
Category :
Languages : en
Pages : 36

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Means for evaluating data bus architectures and protocols for highly integrated flight control system applications are needed. Described are the criteria and plans to do this by using the NASA/Ames Intelligent Redundant Actuation System (IRAS) experimental set-up. Candidate bus architectures differ from one another in terms of: topology, access control, message transfer schemes, message characteristics, initialization. data flow control, transmission rates, fault tolerance, and time synchronization. The evaluation criteria are developed relative to these features. A preliminary, analytical evaluation of four candidate busses (MIL-STD-1553B, DATAC, Ethernet, and HSIS) is described. A bus must be exercised in a real-time environment to evaluate its dynamic characteristics. A plan for real-time evaluation of these four busses using a combination of hardware and simulation techniques is presented. Defeo, P. and Chen, M. Unspecified Center NASA-CR-177458, NAS 1.26:177458 NAS2-12081; RTOP 307-04-02...

Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781721819782
Category :
Languages : en
Pages : 32

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Book Description
The proposed Jupiter Icy Moon Orbiter, JIMO, mission selected a Brayton power conversion system as its electrical power generator. Although the JIMO mission power conversion system was expected to produce in the order of 100 kW, an available 2 kW Brayton system was used to develop control system strategies for the JIMO mission. This report describes the shunt loading voltage/speed regulation control concept developed for the 2 kW system, and the transient performance of controls. The 2 kW alternator is a permanent magnet alternator as proposed for the JIMO mission, and operates at a similar speed and internal impedance, allowing it to be used as an accurate model for performance of the larger system. The JIMO mission was cancelled in September 2005. Birchenough, Arthur G. Glenn Research Center NASA/TM-2006-214043, E-15400

Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781726217309
Category :
Languages : en
Pages : 60

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A government, industry and academic cooperative has developed a Hybrid Electric Transit Bus (HETB). Goals of the program include doubling the fuel economy of city transit buses currently in service, and reducing emissions to one-tenth of EPA standards. Unique aspects of the vehicle's power system include the use of ultra-capacitors for the energy storage system and the planned use of a natural gas fueled turbogenerator, to be developed from a small jet engine. At over 17000 kg gross weight, this is the largest vehicle to use ultra-capacitor energy storage. A description of the HETB, the results of performance testing, and future vehicle development plans are the subject of this report.Brown, Jeffrey C. and Eichenberg, Dennis J. and Thompson, William K.Glenn Research CenterELECTRIC HYBRID VEHICLES; URBAN TRANSPORTATION; ENGINE DESIGN; DESIGN ANALYSIS; PERFORMANCE TESTS; HYBRID PROPULSION; ENERGY STORAGE; CAPACITORS; NATURAL GAS; TURBOGENERATORS; FUEL CONSUMPTION; ENVIRONMENT EFFECTS; TECHNOLOGY TRANSFER; JET ENGINES...

Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781721582280
Category :
Languages : en
Pages : 28

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This effort demonstrates that health management can be taken to the component level for electromechanical systems. The same techniques can be applied to take any health management system to the component level, based on the practicality of the implementation for that particular system. This effort allows various logic schemes to be implemented for the identification and management of failures. By taking health management to the component level, integrated vehicle health management systems can be enhanced by protecting box-level avionics from being shut down in order to isolate a failed computer. Pickett, R. D. Marshall Space Flight Center NASA/TM-2003-212502, M-1077, NAS 1.15:212502