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Viewing 1 to 30 of 3965
2013-04-08
Technical Paper
2013-01-1229
Ajinkya Chinchwadkar, Alok Khare
Currently, OEMs worldwide are emphasizing more upon development and implementation of new electrical features on existing vehicles [3]. However, development and implementation of new electrical features on existing vehicle platforms create architectural as well as packaging challenges. These challenges are augmented due to following: the need to implement such features across different body styles of vehicles that are based on same or different architectures different requirement for a feature based upon market requirement This paper analyzes these challenges to help in providing design solutions for successful implementation of new features as per following requirements: 1 Provide optimum design to have low cost and high quality for existing vehicle platforms2 Provide spare capacity while designing new vehicles or architectures
2012-10-02
Technical Paper
2012-36-0558
Renato Oliveira de Magalhaes, Marcelo Lopes de Oliveira e Souza
The supply of electrical power is one of the most important functions required by the diverse payloads of satellites. A fault in the corresponding subsystem might lead to mission or even vehicle loss. Among the causes of such faults, we highlight the phenomenon of thermal avalanche in batteries. It can be explained as an energetic unbalance where the rate of heat generated in the interior of the system exceeds its capacity to dissipate it. This occurred to the OAO1 of NASA just after its launch on April 8, 1966; and with the CBERS2 of CAST and INPE already in orbit in 2007 and 2009. This work presents a discussion on the causes and effects of thermal avalanches in artificial satellite battery charging and discharging systems.
2012-10-22
Technical Paper
2012-01-2238
Donald J. Kessler
This paper presents an investigation into the feasibility of utilizing commercial off the shelf (COTS) components to implement an optically linked embedded electromechanical actuator (EMA) for aircraft flight control. A joint 1990s USAF, USN, NASA Electrically Powered Actuator Design (EPAD) program sought to replace hydraulically powered aircraft actuators with those powered electrically, either Electrohydrostatic (EHA) or Electromechanical (EMA). A follow-on NASA research effort in 1992 sought to then replace the electrical control links associated with the EHA/EMA with fiber-optic technology [1][2]. Attempts at implementing an optically-linked EMA while successful, experienced technical challenges and exposed fundamental limitations and shortfalls in some of the COTS technologies available at that time.
2012-10-22
Journal Article
2012-01-2211
Terrill B. Atwater, Paula Tavares
The benefits of lithium battery systems lie within their high energy density (Wh/L) and high specific energy (Wh/kg). Manganese dioxide (MnO2) is an attractive active cathode material because of its high energy density and low material cost. Manganese dioxide is an intercalating compound for lithium that functions by solvating and desolvating lithium cations from the electrolyte in solid state. The lithium cations are deposited into the vacancies of the MnO2 cathode crystal structure. The objective of this effort focuses on the limited cycle life of rechargeable lithium manganese-based electrochemical systems, most importantly capacity fading of the cathode. These two characteristics are considered the major technology hurdles in rechargeable lithium battery technology.1, 2, 3, 4
2012-10-22
Journal Article
2012-01-2200
David A. Wetz, Biju Shrestha, Peter M. Novak
The desire of the US Department of Defense (DoD) to field new directed energy systems for a variety of applications increases daily. This desire stems from recent advances in energy storage and solid-state switch technologies, which enable researchers to make systems more compact and energy dense than ever before. While some systems can draw power from the mobile platform on which they are mounted, other systems need to operate independent of a platform and must be completely self-sufficient. The transient and repetitive operation of these directed energy systems requires that the prime energy source provide high power to intermediate energy storage devices. The ability of electrochemical energy storage devices, such as lithium-ion batteries, to source high power quickly has previously been limited. However, battery manufacturers have recently produced cells that are more power dense then previously available.
2014-04-01
Journal Article
2014-01-0347
Seok-san Shin, Hyeongjin Ham, Hyeongcheol Lee
In electronic vehicles (EVs) or hybrid electronic vehicles (HEVs), an inverter system has a direct-current-link capacitor (DC-link capacitor) which provides reactive power, attenuates ripple current, reduces the emission of electromagnetic interference, and suppresses voltage spikes. A film capacitor has been used as the DC-link capacitor in high level power system, but the film capacitor's performance has deteriorated over operating time. The decreasing performance of the film capacitor may cause a problem when supplying and delivering energy from the battery to the vehicle's power system. Therefore, the lifetime prediction of the film capacitor could be one of critical factors in the EVs and HEVs. For this reason, the lifetime and reliability of the film capacitor are key factors to show the stability of the vehicle inverter system. There are a lot of methods to predict the lifetime of the film capacitor.
2006-07-17
Technical Paper
2006-01-2201
M. Schuller, T. Lalk, L. Wiseman, F. Little, O. Godard, S. Abdel-Fattah, R. Askew, D. Klaus, R. Kobrick, G. Thomas, M. Rouen, B. Conger
Conceptual designs for a space suit Personal Life Support Subsystem (PLSS) were developed and assessed to determine if upgrading the system using new, emerging, or projected technologies to fulfill basic functions would result in mass, volume, or performance improvements. Technologies were identified to satisfy each of the functions of the PLSS in three environments (zero-g, Lunar, and Martian) and in three time frames (2006, 2010, and 2020). The viability of candidate technologies was evaluated using evaluation criteria such as safety, technology readiness, and reliability. System concepts (schematics) were developed for combinations of time frame and environment by assigning specific technologies to each of four key functions of the PLSS -- oxygen supply, waste removal, thermal control, and power.
2007-07-09
Technical Paper
2007-01-3082
Marco Molina, Matteo Giacomazzo, Paolo Sabatini, Christian Vettore, Giovanni Annoni, Michela Angelucci
The satellite AGILE (Astro-rivelatore Gamma a Immagini LEggero, “Light Gamma Ray Imaging Detector”) is a promising instrument for near-earth space research of the Italian Space(ASI) during the years 2007-2009: its scientific instrumentation has optimal imaging capabilities in both the gamma-ray energy range (30 MeV - 30 GeV) and hard X-ray range (15 - 45 keV). It will study the phenomena occurring in the high energy spectrum, such as: Active Galactic Nuclei, Gamma Ray Bursts, Gamma-ray Galactic Diffuse Emission, and more. The satellite was designed and built in years 2004-2006; this paper describes the design of the thermal control system of the satellite, with a survey of the flight prediction. As an example of uncertainty reduction, MLI performance characterization by test was done in an early phase of the AIV phase (i.e. well before the system level test), to meet stringent payload requirements in terms of temperature gradients and temperature stability.
1992-08-03
Technical Paper
929081
James P. Noon, Bo H. Cho, Fred C. Lee
The multi-module, multi-phase (MMMP) charger is compared to a single-module (SM) charger to identify potential performance improvements. The advantages of the MMMP charger are documented. This paper then details the design of the MMMP battery charger. The battery charger was developed as part of the NASA EOS Space Platform Testbed Project.
1992-08-03
Technical Paper
929094
A. Subrahmanyam, M. S. Suresh, B. L. Agrawal
Abstract A real time life cycle test, simulating geosynchronous orbit operation, on two Ni-Cd cells and one Ni - H2 cell is in progress. Some significant observations on their cycle performance are reported and discussed in this paper.
1992-08-03
Technical Paper
929106
H. Vaidyanathan, W. H. Kelly, M. W. Earl
The heat dissipated during various rates of charge, overcharge, and discharge of a nickel-hydrogen (Ni/H2) cell was measured using a radiative-type calorimeter. A flight configuration-type Ni/H2 cell was prepared for this study by wrapping the 4-in.-wide cylindrical portion with heater tape and insulating the two dome ends with 10 layers of aluminized Mylar. The radiating surface was limited to the cylindrical portion of the cell. The calorimeter consisted of a liquid-nitrogen-cooled copper chamber arranged inside a vacuum jar. Since the experiments were not performed under isothermal conditions, the term was included in the equation used to calculate heat dissipation. Experimentally measured heat values were compared against those calculated using a thermoneutral potential of 1.51 V.
1992-08-03
Technical Paper
929110
Hong S. Lim
Abstract Open circuit storage tests of discharged Ni/H2 cells have been carried out at 20°C to understand effects of cell design parameters on capacity fading with storage and determine capacity fading mechanism. Cell design parameters studied include variations in the electrode substrate (dry powder or wet slurry sinter), active material impregnation technique (alcoholic or aqueous bath), cobalt additive concentrations (4 to 10%), KOH concentration (26 or 31%), and cell precharge (nickel or H2). Precharge had the most dominant effect of all parameters. When cells had nickel precharge, virtually no fading was observed with storage up to 188 days, while gradual fading was observed with all H2 precharged cells. Tendency of capacity fading of these cells depended on KOH concentration, impregnation technique, and cobalt concentration. Cell pressure changes with storage were consistent with build-up of electrochemically undischargeable active material with capacity fading.
1992-08-03
Technical Paper
929319
J. C. Garner
The Naval Research Laboratory (NRL) and Johnson Controls Inc. (JCI) have joined together in a cooperative research and development effort to “space qualify” the JCI Common Pressure Vessel (CPV) Nickel Hydrogen (NiH2) battery. JCI is providing two (2) NiH2 batteries to NRL. One is for qualification tests and the second is for the flight experiment. NRL is responsible for the design, test and integration of the battery with an existing spacecraft electrical power system, launch of the battery with the host spacecraft, and providing data from the flight experiment. Since the intent of the experiment is to “space qualify” the JCI NiH2 CPV design, the battery will be “on-line” and fully charged during the launch of the host spacecraft. This paper will describe the NRL-JCI Cooperative Research and Development Agreement, the NiH2 CPV battery experiment design, and the qualification test program.
1992-08-03
Technical Paper
929325
Glenn C. Klein
Gates Aerospace Batteries has developed a dedicated reliability function in conjunction with an R & D effort for the NiMH couple. Thus, the preliminary reliability analyses and assessments are being performed in parallel to the NiMH cell design development. The NiMH cell development effort comes from two distinct directions within Gates Energy Products. First, the Gates Energy Products' Sub-C wound commercial NiCd cell is being used for extensive initial investigations. Second, the Gates Aerospace Batteries' mature NiCd Aerospace Product Line provides a close similarity to many of the design features to be used with the NiMH couple. Due to this close similarity, the baseline reliability assessment becomes the Design Trade-Off. The trade-off draws from these two distinct directions and develops an assessment of characteristic differences and from then on analyzes both the primary and secondary effects. The trade-off is categorized into four specific areas.
1992-08-03
Technical Paper
929326
Michelle A. Manzo
A cooperative agreement has been established between NASA and Gates Aerospace Batteries (GAB) to investigate modifications to the NASA Standard nickel-cadmium (Ni-Cd) cell designs. These modifications are aimed at identifying the parameters required to maximize the life of Ni-Cd cells made with plates produced by the chemical impregnation process routinely used at Gates Aerospace Batteries. Modifications to positive plates, negative plates, separators, inter-electrode spacing, and electrolyte fill levels are being investigated. The initial evaluation involves variation of positive plate production parameters including nickel attack level as controlled by passivation and impregnation, loading level and impregnation technique; negative plate loading levels, negative to positive ratios and inter-electrode spacing.
1992-07-01
Technical Paper
921366
W. H. Kelly, H. Vaidyanathan
The thermal dissipation of a 48-Ah nickel-hydrogen (Ni/H2) battery cell has been derived by testing it in a controlled radiative environment. Temperature profiles and corresponding cell thermal dissipations are presented for different battery discharge/charge cycles. A comparison between test results and theoretical predictions for battery dissipation is presented. The thermal capacitance of a Ni/H2 cell is computed from both test data and tabulation of individual cell component weight and specific heat.
1994-04-01
Technical Paper
941160
E. Richter, J.P. Lyons, C. Ferreira, A. V. Radun, E. Ruckstadter
The work reported in this paper has been conducted by a team from GE-Aircraft Engines, GE-CR&D, and Sundstrand under a contract sponsored by the USAF, Wright Laboratories, WPAFB, Contract No. F33615-90-C-2052. The objective of this contract is to prove the feasibility of an Integral Starter/Generator (IS/G) through the preliminary design stage and demonstrate the starter/ generator technology in the externally mounted version utilizing switched reluctance machine technology. This paper will report on the progress for the EIS/G-system through the initial testing stage. Comparison of the finished hardware with the design results presented earlier will lead of the paper. This is followed by the discussion of the early testing results for the system testing. Recommendation on additional testing will be presented at the end of the paper.
1994-04-01
Technical Paper
941162
Arthur Radun, James P. Lyons, James Rulison, Peter Sanza, Eike Richter
Preliminary testing of a 125kW power inverter for a switched reluctance aircraft engine starter/generator system has been completed and system testing of the complete starter/generator system has been initiated. The starter/generator employs a single switched reluctance machine (SRM) and a generating system architecture that produces two separate 270Vdc buses from that single SRM The machine has six phases with three of the phases connected to one inverter supplying 125kW to one 270Vdc bus while the other three phases are connected to a second inverter supplying 125kW to the other 270Vdc bus. Each bus has its own EMI filter and controller in addition to its own inverter. Two types of inverters have been developed, one type employs MOS Controlled Thyristors for the controlled switches and the other type employs Insulated Gate Bipolar Transistors. The link capacitor bank for each inverter employs multilayer ceramic capacitors to meet the starter/generator's temperature requirements.
1991-09-01
Technical Paper
912172
Richard Michael Haas
Batteries which are used in airborne electrical systems must provide a very high discharge current for APU starting and offer virtually maintenance free service. To achieve this kind of performance for hundreds of operational cycles, it is important to consider the behavior of a battery under actual operating conditions. Several functional parameters such as terminal voltage, state of charge, internal impedance and temperature are continuously changing depending on past and present operating conditions. In order to evaluate the available energy which a battery can deliver at any given time, it is necessary to maintain a log of the State Of Charge Index (SOCI). This numerical indicator is based on a functional relationship between terminal voltage, current flow, elapsed time and internal temperature. These parameters are continuously monitored and periodic measurements are converted into a standard index factor.
1991-04-01
Technical Paper
911160
Jeffrey P. Zagrodnik, Kenneth R. Jones
Abstract Johnson Controls, Inc. has developed a multiple cell CPV Nickel Hydrogen battery that offers significant weight, volume and cost advantages for aerospace applications. The baseline design was successfully demonstrated through the testing of a 26-cell prototype, which completed over 7,000 44% depth-of-discharge LEO cycles at COMSAT Laboratories. Prototype designs using both nominal 5″ and 10″ diameter vessels are currently being developed for a variety of space and aircraft applications. Nickel Hydrogen batteries are well established as an energy storage subsystem for commercial communication satellites. The standard design has been the Individual Pressure Vessel (IPV), which provides an independent vessel for each cell of the battery. The comparative advantages of a Common Pressure Vessel (CPV) design configuration, in which many series connected cells are contained in a single vessel, are widely recognized.
1995-05-01
Technical Paper
951453
Arthur Radun, Jimmie Cathey, Martin R. Pais, Edward Durkin, Joseph Weimer
Abstract The development of the more electric aircraft is in progress. An important part of more electric aircraft concept is the integral starter/generator (ISG) mounted on the shaft of the jet engine. The prime candidate technology for the ISG is a system based on the switched reluctance motor (SRM). Switched reluctance technology has been chosen for this application because the a single failure does not lead to a complete loss of electrical power. In fact, each phase of the SRM is essentially independent of every other phase. Thus it is possible to be able to loose a single phase as a result of a fault and still remain operational with all of the other phases. This characteristic of the SRM has been referred to as fault tolerance and it is a very important characteristic when there is only one generator per engine.
1995-05-01
Technical Paper
951407
A. V. Radun, Y. Q. Xiang
Abstract - System modeling and simulation results for an experimental switched reluctance external integral starter/generator (EISG) are reported. The EISG system employs a single switched reluctance machine and a generating system architecture that produces two separate 270 Vdc buses from that single switched reluctance machine. The machine has six phases with three of the phases connected to one converter supplying 125 kW to one 270 Vdc bus while the other three phases are connected to a second converter supplying 125 kW to the other 270 Vdc bus. Each bus has its own EMI filter and control in addition to its own converter. Two separate system models have been developed for the EISG. One of these models has been denoted the averaged model and the other has been denoted the detailed model. Both models include the switched reluctance machine and power electronics, the EMI filter, and the feedback control. The development of both of these models is described.
1994-04-01
Technical Paper
941195
Scott D. Sudhoff, Paul C. Krause, Oleg Wasynczuk, Barbara H. Kenny, Irving H. Hansen
The steady-state and dynamic performance of a candidate aircraft power distribution system is considered. The system features distribution of both single phase 20-kHz and three-phase 400-Hz power. It is shown that unlike some other recent 20-kHz systems, the power quality of the 20-kHz bus is not a concern due to the use of a synchronous bi-directional rectifier (SBR) as the primary interface to the 20-kHz bus. In addition to showing that the system behaves adequately in the steady-state, the dynamic performance of the system is considered during step changes in load, bolted faults, and sudden variations in jet engine speed.
1995-07-01
Technical Paper
951717
David Antoniuk
The Capillary Pumped Loop (CAPL) experiment, consisting of four tubular evaporator elements configured in parallel, a dedicated starter pump, four condenser elements, and a heatpipe radiator, was tested in microgravity onboard the Space Transportation System (STS). All twenty attempts at starting the system from the flooded state using a ground-proven procedure were unsuccessful. These unexpected events are attributed to the failure of the startup procedure to clear the liquid flooding the vapor spaces of the evaporator elements before heat was applied to the evaporators. Emptying of these vapor spaces prior to the application of a heat load had been found necessary to prevent a postulated vapor blow-by mechanism that can potentially lead to arterial depriming by injection of bubbles into the liquid core of the capillary pumps.
1991-07-01
Technical Paper
911409
Alain Lanteri, C.W.B. Potts, Peter Moeller, J. Held, H. Kreeb
Abstract The BSTCA (Battery Section Thermal Control Assembly) is a module of the Columbus MTFF (Man Tended Free Flyer). Electrical power required during eclipse periods, is made available from six nickel hydrogen batteries. A sophisticated multi-radiator configuration, with a hybrid heat pipe network, has evolved. Autonomous control of the assembly heat rejection capability has been achieved by a integrated network of LTHP's (Liquid Trap Heat Pipes) and CCHP's (Constant Conductance Heat Pipes) under the control of a conventional HCU (Heater Control Unit). The process of design selection and verification is discussed, for the BSTCA, with a detailed LTHP component presentation.
1991-07-01
Technical Paper
911447
Jost Munder, Manfred Bader, Peter Moeller
The thermal control subsystem of the Columbus Resource Module has to cope with an unusual variety of orbit attitudes, mission modes and configurations. A short overview over the past RM thermal concepts is given and the present thermal design is described in detail. A passive concept with extensive use of heatpipes configured as network is baselined. The low available heater power in conjunction with the significant dissipation variations of th NiH2 batteries require there a very effective heat rejection control concept. A new regulation concept has been selected which allows to switch off up to 75% of the battery radiator area by use of Liquid Trap Heatpipes. The verification concept which does not use system level testing is briefly described.
1990-08-01
Technical Paper
901511
Russell Read, Doug Raponi, Brian Kemp, Eric Thatcher, Pat Rutkauskas, Tom Sherwin
Clarkson University is one of 32 teams competing in the GM SunRayce USA during July 1990. This paper describes design strategy and results for the electrical systems of the Kalahkwaneha. In particular, the solar array, power trackers, drive train, instrumentation, telemetry and safety features are examined.
1993-04-01
Technical Paper
931388
Arthur Radun, Eike Richter
The design results for a 250 kW switched reluctance aircraft engine starter/generator system power inverter are presented. The starter/generator employs a single switched reluctance machine and a generating system architecture that produces two separate 270 Vdc buses from that single switched reluctance machine. The machine has six phases with three of the phases connected to one inverter supplying 125 kW to one 270 Vdc bus while the other three phases are connected to a second inverter supplying 125kW to the other 270 Vdc bus. Each bus has its own EM1 filter and control in addition to its own inverter. Two types of inverters have been developed, one type employs MOS Controlled Thyristors (MCTs) for the controlled switches and the other type employs Insulated Gate Bipolar Transistors (IGBTs). High-current 500 A peak turn-off MCT modules were specifically developed for the MCT inverters. Two of these modules are placed in parallel to form the required 1000 A switches.
1993-04-01
Technical Paper
931389
C.A. Ferreira, Eike Richter
The work reported in this paper has been conducted by General Electric Company and Sundstrand Corporation as part of a contract sponsored by the USAF, Wright Laboratories, and WPAFB under contract no. F33615-90-C-2052. The objective of this contract is to prove the feasibility of an integral starter/generator (IS/G) through the preliminary design stage and demonstrate the starter/generator technology in the externally-mounted version (EIS/G) using switched reluctance (SR) machine technology. This paper reports on the detailed design and analysis of the EIS/G. The analysis and design encompassed definition of requirements and constraints, electromagnetic design, thermal analysis, mechanical stress and fit analysis, bearing and critical speed analysis, and mechanical layout and packaging.
1993-04-01
Technical Paper
931390
J. J. Cathey, S. A. Chickamenahalli, R. R. Bhuiya
A novel, two-phase, switched reluctance machine concept is presented. Pole side shaping assures that the machine can develop motoring torque from any static position. Pole face shaping is introduced to control the nature of flux linkages as a function of position, allowing reduction in position-dependent torque ripple over conventional switched reluctance machines. Since the machine has 50% of the magnetic circuit active at any point in time, whereas the three-phase switched reluctance machine has 33% of the magnetic circuit instantaneously active, the new design shows increased power density over the common three-phase machine.
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