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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 955 records · Page 53
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Grid and Wind Transient Ride Through Assessment of Type-5 Synchronous Wind Turbine

The integration of the inverter-based renewable energy resources is increasing and replacing conventional synchronous generators in the evolving bulk power system (BPS), impacting the system inertia along the way. Also, the limited over-current capability of power electronic converters continues to deteriorate the grid strength of the evolving power systems. Type-5 wind turbines have the potential to mitigate these problems because this configuration interfaces with the grid through a synchronous generator; hence, its operation and consequent grid impacts might mimic the conventional synchronous generator. The drivetrain of this type of turbines, however, is different from the more common Type-3 and Type-4 turbines. A hydraulic torque converter and gearbox with torque limiting feature are integral parts of a Type-5 wind turbine drivetrain, to isolate the wind speed variations at the wind turbine rotor from the grid connected generator side. This supports the synchronous operation of the generator. However, high fidelity models of Type-5 wind turbine drivetrain including these core components are not openly and widely available for grid integration and transient stability studies. Moreover, Type-5 turbines are not commonly deployed and hence its power generation and frequency stability characteristics are not widely publicized. This hinders appropriate assessment of Type-5 wind power plant's contribution to bulk grid resilience. This work provides transient stability assessment of a standalone Type-5 wind turbine. Normal operation and grid transient studies are performed to see the step load change and wind speed disturbance impacts on the Type-5 drivetrain and generation dispatch. Preliminary results show that Type-5 wind turbines can support load changes of between 0.6 p.u to 1.15 p.u. Beyond this point, the synchronization of the generator starts to deviate from its set point.

17 - WIND ENERGY↗
DOE OSTI2014

High-voltage field effect transistors with wide-bandgap β-Ga{sub 2}O{sub 3} nanomembranes

Nanoscale semiconductor materials have been extensively investigated as the channel materials of transistors for energy-efficient low-power logic switches to enable scaling to smaller dimensions. On the opposite end of transistor applications is power electronics for which transistors capable of switching very high voltages are necessary. Miniaturization of energy-efficient power switches can enable the integration with various electronic systems and lead to substantial boosts in energy efficiency. Nanotechnology is yet to have an impact in this arena. In this work, it is demonstrated that nanomembranes of the wide-bandgap semiconductor gallium oxide can be used as channels of transistors capable of switching high voltages, and at the same time can be integrated on any platform. The findings mark a step towards using lessons learnt in nanomaterials and nanotechnology to address a challenge that yet remains untouched by the field.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
NASA NTRS2009

Pixelized Device Control Actuators for Large Adaptive Optics

A fully integrated, compact, adaptive space optic mirror assembly has been developed, incorporating new advances in ultralight, high-performance composite mirrors. The composite mirrors use Q-switch matrix architecture-based pixelized control (PMN-PT) actuators, which achieve high-performance, large adaptive optic capability, while reducing the weight of present adaptive optic systems. The self-contained, fully assembled, 11x11x4-in. (approx.= 28x28x10-cm) unit integrates a very-high-performance 8-in. (approx.=20-cm) optic, and has 8-kHz true bandwidth. The assembled unit weighs less than 15 pounds (=6.8 kg), including all mechanical assemblies, power electronics, control electronics, drive electronics, face sheet, wiring, and cabling. It requires just three wires to be attached (power, ground, and signal) for full-function systems integration, and uses a steel-frame and epoxied electronics. The three main innovations are: 1. Ultralightweight composite optics: A new replication method for fabrication of very thin composite 20-cm-diameter laminate face sheets with good as-fabricated optical figure was developed. The approach is a new mandrel resin surface deposition onto previously fabricated thin composite laminates. 2. Matrix (regenerative) power topology: Waveform correction can be achieved across an entire face sheet at 6 kHz, even for large actuator counts. In practice, it was found to be better to develop a quadrant drive, that is, four quadrants of 169 actuators behind the face sheet. Each quadrant has a single, small, regenerative power supply driving all 169 actuators at 8 kHz in effective parallel. 3. Q-switch drive architecture: The Q-switch innovation is at the heart of the matrix architecture, and allows for a very fast current draw into a desired actuator element in 120 counts of a MHz clock without any actuator coupling.

Knowles, Gareth J.↗
DOE OSTI2019

The application of macroscopic flakes for Fe-6.5%Si bulk magnetics with superior magnetic properties

Inductors are used in power electronics to convert current to different frequency and voltage. They are used extensively from where power is generated all the way to electric vehicles and portable electronic devices. The soft magnetic materials used in the inductors is critical for the performance of the inductors. Currently, a majority of the inductor uses powder core. The use of powder is not ideal as the 3D granule powders generate large demagnetization field working against the applied field, resulting in reduced permeability and efficiency. In this paper, 2D flakes were used to replace the 3D granules as the feedstock for fabricating inductor core. The crystalline Fe-Si based crystalline soft magnetic material in the form of flakes approximately 0.1mm thick, 1mm long and 2mm wide were prepared via melt spinning. The flakes were then coated with insulating materials before compacted into a toroid. The effect of coating thickness and concentration on magnetic properties of the toroidal sample are studied. It was also found that the magnetic cores made by flakes surpass the cores made by same size powder with larger permeability and lower iron losses.

Fe-6.5%Si Steel↗
DOE OSTI2014

Unraveling resistive versus collisional contributions to relativistic electron beam stopping power in cold-solid and in warm-dense plasmas

We present results on laser-driven relativistic electron beam propagation through aluminum samples, which are either solid and cold or compressed and heated by laser-induced shock. A full numerical description of fast electron generation and transport is found to reproduce the experimental absolute K{sub α} yield and spot size measurements for varying target thicknesses, and to sequentially quantify the collisional and resistive electron stopping powers. The results demonstrate that both stopping mechanisms are enhanced in compressed Al samples and are attributed to the increase in the medium density and resistivity, respectively. For the achieved time- and space-averaged electronic current density, 〈j{sub h}〉∼8×10{sup 10} A/cm{sup 2} in the samples, the collisional and resistive stopping powers in warm and compressed Al are estimated to be 1.5 keV/μm and 0.8 keV/μm, respectively. By contrast, for cold and solid Al, the corresponding estimated values are 1.1 keV/μm and 0.6 keV/μm. Prospective numerical simulations involving higher j{sub h} show that the resistive stopping power can reach the same level as the collisional one. In addition to the effects of compression, the effect of the transient behavior of the resistivity of Al during relativistic electron beam transport becomes progressively more dominant, and for a significantly high current density, j{sub h}∼10{sup 12} A/cm{sup 2}, cancels the difference in the electron resistive stopping power (or the total stopping power in units of areal density) between solid and compressed samples. Analytical calculations extend the analysis up to j{sub h}=10{sup 14} A/cm{sup 2} (representative of the full-scale fast ignition scenario of inertial confinement fusion), where a very rapid transition to the Spitzer resistivity regime saturates the resistive stopping power, averaged over the electron beam duration, to values of ∼1 keV/μm.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2023

Modeling and Analysis Support for Acceleratro-based Production of Mo-99

NorthStar Medical Radioisotopes, LLC, is in the process of commissioning a medical isotope production facility, which will use high-power electron accelerators to produce molybdenum-99 (Mo-99), the parent of technetium-99m (Tc-99m), through photonuclear reactions in molybdenum-100 (Mo-100). In this approach, a target comprising multiple thin disks of enriched molybdenum metal is bombarded with a 40-MeV electron beam. Electrons that impinge on the molybdenum target produce bremsstrahlung x-rays that cause the nuclear reaction. Because enriched Mo-100 is expensive, there is a desire to use as much beam power as possible to achieve maximum production yield and minimize the size of the target. This requirement leads to very high beam power density (heat deposition in the target), which creates challenging requirements for target cooling. In the latest concept developed by NorthStar, a stack of target (sintered molybdenum) disks is irradiated from two sides by a 40-MeV electron beam, with a total power of 250 kW (125 kW from each side). The target disks are cooled by pressurized helium gas flowing through channels between the disks. Inconel windows in the target housing form a pressure boundary between the helium within the housing and the evacuated beam tube.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2018

Network-Cognizant Model Reduction of Grid-Tied Three-Phase Inverters

Power-electronics inverters are expected to satisfy a significant fraction of system load in next-generation power networks with the growing integration of renewable resources and flexible loads. Typical dynamical models for grid-tied inverters are nonlinear and composed of a large number of states; therefore it is impractical to study systems with many inverters when their full dynamics are retained. In our previous work, we have shown that a system of parallel-connected grid-tied three-phase inverters can be modeled as one aggregated inverter unit with the same structure and state-space dimension as any individual inverter in the system. Here, we extend this result to networks with arbitrary topologies by leveraging a classical aggregation method for coherent synchronous generators in transmission networks, and a linear approximation of the AC power-flow equations to ease computational burden. Numerical simulation results for a prototypical distribution feeder demonstrate the accuracy and computational benefits of the approach.

24 POWER TRANSMISSION AND DISTRIBUTION↗
NASA NTRS2000

Wide-Temperature Electronics for Thermal Control of Nanosats

This document represents a presentation which examines the wide and low-temperature electronics required for NanoSatellites. In the past, larger spacecraft used Radioisotope Heating Units (RHU's). The advantage of the use of these electronics is that they could eliminate or reduce the requirement for RHU's, reduce system weight and simplify spacecraft design by eliminating containment/support structures for RHU's. The Glenn Research Center's Wide/Low Temperature Power Electronics Program supports the development of power systems capable of reliable, efficient operation over wide and low temperature ranges. Included charts review the successes and failures of various electronic devices, the IRF541 HEXFET, The NE76118n-Channel GaAS MESFET, the Lithium Carbon Monofluoride Primary Battery, and a COTS DC-DC converter. The preliminary result of wide/low temperature testing of CTS and custom parts and power circuit indicate that through careful selection of components and technologies it is possible to design and build power circuits which operate from room temperature to near 100K.

Dickman, John Ellis↗
DOE OSTI2015

Investigation of Donor and Acceptor Ion Implantation in AlN

AlGaN alloys with high Al composition and AlN based electronic devices are attractive for high voltage, high temperature applications, including microwave power sources, power switches and communication systems. AlN is of particular interest because of its wide bandgap of ~6.1eV which is ideal for power electronic device applications in extreme environments which requires high dose ion implantation. One of the major challenges that need to be addressed to achieve full utilization of AlN for opto and microelectronic applications is the development of a doping strategy for both donors and acceptors. Ion implantation is a particularly attractive approach since it allows for selected-area doping of semiconductors due to its high spatial and dose control and its high throughput capability. Active layers in the semiconductor are created by implanting a dopant species followed by very high temperature annealing to reduce defects and thereby activate the dopants. Recovery of implant damage in AlN requires excessively high temperature. In this SBIR program we began the investigation by simulation of ion beam implantation profiles for Mg, Ge and Si in AlN over wide dose and energy ranges. Si and Ge are implanted to achieve the n-type doping, Mg is investigated as a p-type doping. The simulation of implantation profiles were performed in collaboration between NRL and Agnitron using a commercial software known as Stopping and Range of Ions in Matter (SRIM). The simulation results were then used as the basis for ion implantation of AlN samples. The implanted samples were annealed by an innovative technique under different conditions and evaluated along the way. Raman spectroscopy and XRD were used to determine the crystal quality of the implanted samples, demonstrating the effectiveness of annealing in removing implant induced damage. Additionally, SIMS was used to verify that a nearly uniform doping profile was achieved near the sample surface. The electrical characteristics of the implanted samples were evaluated by TLM and Hall techniques. Generally, the implanted samples before and after annealing were found to be very resistive. Further work is required before the superior properties of AlN can be fully utilized.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2022

A case study of high-temperature polyetherimide film capacitor fabrication

Capacitors, as the basic building block of power electronics and electrical systems, are the major constraint of the increasingly integrated power systems that require new capable polymer dielectric films operating at higher temperatures >125 °C. Despite tremendous research efforts on the lab scale, there remains a considerable barrier and knowledge basis for converting polymeric films to functioning capacitors desired in actual applications. Here, the authors tackled the polyetherimide (PEI) film scale up issues and developed various engineering processes for film de-wrinkling, optimal metallization, static elimination, and capacitor fabrication improvement. The authors discovered various fabrication challenges such as the electrostatic charge, metallization scheme, winding tension, and end electrode disconnects. To fabricate a high yield of PEI capacitor bobbins, it is necessary to utilize static eliminators (radioactive ionizers), moderately thick aluminum metallization (15–30 Ω/sq), and winding tension (60–100 g). It is also effective to evaluate capacitance, dielectric loss, equivalent series resistance, and thermal cycling stability of capacitors. This work sheds some light on converting PEI films and other polymeric films to capacitors on a scale up fabrication effort. The practical learning from film handling to capacitor fabrication in this work provided the necessary knowledge for manufacturing high-temperature polar film capacitors.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Design of a Single Controller for Multiple Paralleled Inverters

Paralleling power electronics inverters is an effective way to increase dc-ac system power level. Accurately synchronized switching action and independent closed-loop regulator are necessary to prevent circulating current in paralleled inverters. There are many challenges for the controller design, when the number of paralleled inverters is large, and control period gets short for high switching frequency applications. This paper presents a single controller design based on DSP + FPGA that is suitable for paralleling multiple inverters. A simple synchronization scheme between DSP and FPGA based on universal parallel port (UPP) is proposed to eliminate the synchronization delay among inverters, and independent control of each converter can also be implemented. The controller is built for a system consisting of 4 paralleled three-level, three-phase high frequency ANPC inverters using space vector modulation, and it can be easily adopted to other topologies and modulations. Experimental results have demonstrated the effectiveness of this controller.

Niu, Jiahao↗
DOE OSTI2022

3.5 kW/in3 Planar Coupled Inductor Design and Optimization for a 50 kW 3-level Four-Switch Buck-Boost (3L-FSBB) Converter

Planar magnetics design has been widely used in power electronics field because of the low profile, ease of manufacturability, and high power density. This paper first proposes a 3-level four-switch buck-boost (3L-FSBB) converter for the dc-dc applications where the zero common-mode (CM) voltage emissions, step-up and step-down are all required. With the consideration of power density, efficiency, and cost, a 15oz heavy copper coupled inductor for 3-level FSBB converter was designed and optimized with the low-cost commercial core and planar windings. According to the soft-switching quadrangle modulation for 3-L FSBB, the turns number and stacked core number are optimized first. And then, a two-board design is proposed to reduce the fringing effect and improve the thermal performance. Finally, a 75 kVA two-stage ac-dc-dc converter including a 3-level FSBB converter was built to verify the electrical design.

Cao, Yuliang↗
DOE OSTI2013

TidGen Power System Commercialization Project

ORPC Maine, LLC, a wholly-owned subsidiary of Ocean Renewable Power Company, LLC (collectively ORPC), submits this Final Technical Report for the TidGen® Power System Commercialization Project (Project), partially funded by the U.S. Department of Energy (DE-EE0003647). The Project was built and operated in compliance with the Federal Energy Regulatory Commission (FERC) pilot project license (P-12711) and other permits and approvals needed for the Project. This report documents the methodologies, activities and results of the various phases of the Project, including design, engineering, procurement, assembly, installation, operation, licensing, environmental monitoring, retrieval, maintenance and repair. The Project represents a significant achievement for the renewable energy portfolio of the U.S. in general, and for the U.S. marine hydrokinetic (MHK) industry in particular. The stated Project goal was to advance, demonstrate and accelerate deployment and commercialization of ORPC’s tidal-current based hydrokinetic power generation system, including the energy extraction and conversion technology, associated power electronics, and interconnection equipment capable of reliably delivering electricity to the domestic power grid. ORPC achieved this goal by designing, building and operating the TidGen® Power System in 2012 and becoming the first federally licensed hydrokinetic tidal energy project to deliver electricity to a power grid under a power purchase agreement in North America. Located in Cobscook Bay between Eastport and Lubec, Maine, the TidGen® Power System was connected to the Bangor Hydro Electric utility grid at an on-shore station in North Lubec on September 13, 2012. ORPC obtained a FERC pilot project license for the Project on February 12, 2012 and the first Maine Department of Environmental Protection General Permit issued for a tidal energy project on January 31, 2012. In addition, ORPC entered into a 20-year agreement with Bangor Hydro Electric Company on January 1, 2013 for up to 5 megawatts at a price of $215/MWh, escalating at 2.0% per year.

16 TIDAL AND WAVE POWER↗
NASA NTRS1980

Development of space-qualified GaAs solar cells

Cells 2 cm x 2 cm were produced having an efficiency of 16% at 100 C and 12% at 200 C. They were superior to silicon cells under 1 MeV electron bombardment up to fluences in excess of 10 to the 15th power electron per sq cm, and to protons with an energy in excess of 1 MeV. The possibility of producing cells in quantity using a graphite wafer holder is mentioned.

Knechtli, R. C.↗
NASA NTRS2002

High Performance Power Module for Hall Effect Thrusters

Previous efforts to develop power electronics for Hall thruster systems have targeted the 1 to 5 kW power range and an output voltage of approximately 300 V. New Hall thrusters are being developed for higher power, higher specific impulse, and multi-mode operation. These thrusters require up to 50 kW of power and a discharge voltage in excess of 600 V. Modular power supplies can process more power with higher efficiency at the expense of complexity. A 1 kW discharge power module was designed, built and integrated with a Hall thruster. The breadboard module has a power conversion efficiency in excess of 96 percent and weighs only 0.765 kg. This module will be used to develop a kW, multi-kW, and high voltage power processors.

Pinero, Luis R.↗
NASA NTRSDate not supplied

Power System Redundancy Design Trends for All-Electric eVTOL Quadrotors

Electrical vertical takeoff and landing (eVTOL) vehicles promise to enable a variety of new local and intraregional air transport missions. However, there are significant challenges that must be solved to enable their use. One challenge is the relatively low reliability of power components (e.g. motors, power electronic devices, and batteries). No clear development path to create reliable eVTOL power systems has been articulated in the literature, though it is generally assumed redundancy is part of the solution. This work proposes an analysis process to examine the redundancy design space and select mass optimal designs for eVTOL power systems. The process is applied to a six passenger quadrotor vehicle, and results are used to highlight redundancy design trends for this class of vehicle. This process and associated data can help vehicle designers more effectively develop eVTOLs that meet reliability requirements.

Electric vertical takeoff and landing↗
NASA NTRSDate not supplied

Power System Redundancy Design Trends for All-Electric eVTOL Quadrotors

Electrical vertical takeoff and landing (eVTOL) vehicles promise to enable a variety of new local and intraregional air transport missions. However, there are significant challenges that must be solved to enable their use. One challenge is the relatively low reliability of power components (e.g. motors, power electronic devices, and batteries). No clear development path to create reliable eVTOL power systems has been articulated in the literature, though it is generally assumed redundancy is part of the solution. This work proposes an analysis process to examine the redundancy design space and select mass optimal designs for eVTOL power systems. The process is applied to a six passenger quadrotor vehicle, and results are used to highlight redundancy design trends for this class of vehicle. This process and associated data can help vehicle designers more effectively develop eVTOLs that meet reliability requirements.

Electric vertical takeoff and landing↗