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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 289 records · Page 16
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Reliable Power Hibernation and Recovery for Solar Powered Lunar Missions

NASA Glenn Research Center has been working on a solution to surviving the lunar night based on the discovery that Li-Ion cells can survive the freeze/thaw process. This implies that a lunar surface spacecraft could hibernate through the coldest portions of the night and recover at lunar dawn. Survival and recovery also depend on power electronics capable of tolerating the cold and reliably starting at lunar dawn based on solar array output alone. GRC is working with STMD Space Technology Research Grant investigators to characterize Li-ion cells through the freeze-thaw process and fully understand the electro-chemical and thermal-mechanical processes to assure reliable cell hibernation and recovery. Further, we are working with investigators to determine what power semiconductor material, transistor technology, and power architecture is best suited for reliable cold start at lunar dawn and methodically restoring the power system to full operation for the next lunar cycle.

Spacecraft Power↗
NASA NTRSDate not supplied

Power Hibernation for Low-Cost Solar Powered Lunar Missions

Lunar Surface temperatures can span from equatorial highs near 400K and polar lows of 50K. The extreme cold combined with the 354-hour duration of the lunar night is particularly challenging for small robotic lander missions. NASA’s Commercial Lunar Payload Services (CLPS) missions involve robotic landers intended to provide low-cost access to the lunar surface. Current CLPS Missions are solar powered and are only intended to survive a single lunar day. The ability to survive the night and continue operations over many lunar cycles would provide a dramatic increase in science productivity. The Power Hibernation approach relies on battery cells that can tolerate the extreme cold night and recover once temperatures return to normal. System recovery from hibernation depends on power electronics that can “cold start” at lunar dawn and operate on solar array output alone. Once battery and avionics systems are restored the spacecraft resumes daytime operations. The challenge is to achieve this capability with minimum impact to the spacecraft design and payload capacity. This talk will describe recent and ongoing investigations in battery and electronics technologies that will enable power hibernation and recovery.

Space Power↗
NASA NTRSDate not supplied

Power Hibernation for Low-Cost Solar Powered Lunar Missions

Lunar Surface temperatures can span from equatorial highs near 400K and polar lows of 50K. The extreme cold combined with the 354-hour duration of the lunar night is particularly challenging for small robotic lander missions. NASA’s Commercial Lunar Payload Services (CLPS) missions involve robotic landers intended to provide low-cost access to the lunar surface. Current CLPS Missions are solar powered and are only intended to survive a single lunar day. The ability to survive the night and continue operations over many lunar cycles would provide a dramatic increase in science productivity. The Power Hibernation approach relies on battery cells that can tolerate the extreme cold night and recover once temperatures return to normal. System recovery from hibernation depends on power electronics that can “cold start” at lunar dawn and operate on solar array output alone. Once battery and avionics systems are restored the spacecraft resumes daytime operations. The challenge is to achieve this capability with minimum impact to the spacecraft design and payload capacity. This talk will describe recent and ongoing investigations in battery and electronics technologies that will enable power hibernation and recovery.

Space Power↗
DOE OSTI2026

Power and particle exhaust in the ST-E1 fusion power plant

Power exhaust challenges and potential solutions for a 5 m major radius, low-aspect ratio burning tokamak have been explored. 1D edge plasma models have been used to screen for access to detachment using short and long outer divertor legs in double and single null configurations, using Ar as the primary impurity and assuming tungsten plasma-facing components (PFCs). These show that detachment access can be accessed for all but the most conservative assumptions on scrape-off layer (SOL) width and power, but that trade-offs will be required between magnet engineering and the size of the acceptable window of as-yet uncertain plasma parameters. SOLPS-ITER was used to further model selected plasma scenarios, confirming that Ar seeding can be used to achieve dissipative divertor scenarios with peak deposited heat fluxes below 15 MWm -2 . Initial scoping of first wall loads and positioning of limiters has been carried out, showing the feasibility of protecting the breeding blanket wall during steady state without impeding tritium breeding. Initial PFC technology selection is also presented, identifying this as a critical area where further work is needed to find an attractive solution for helium-cooled PFCs that can handle high heat fluxes without excessive power requirements. Key questions and trade-offs for concept development have been identified, including: how to achieve high radiation for reduction of SOL power without core performance degradation; whether power exhaust can be well-controlled in a double null plasma; mechanical design and materials challenges of high-heat flux PFCs; and control of material erosion, redeposition and tritium retention.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2021

Stability Quantification for Consensus-Based Power Flow Control between Transmission and Distribution Power Systems

With increasing integration of distributed energy resources (DERs), distribution systems (DS) with DERs are expected to provide proactive grid services. The result is that power references, or known as dispatch signals, required for DS can become faster changing than in legacy power system. Consensus-based integral controls have been proposed for the purpose of coordinating power generations of DERs in DS to match the power references. These existing controls assume the integral control signal to be sufficiently slow or constant, and ignore the potential dynamics of the integral controller when tracking more varying power references. Therefore, in this paper we present an improvement for such controls by deriving the stability condition utilizing generalized Nyquist criterion. The stability condition is quantified by a set of integral gains that guarantee stability in closed-loop system without assuming a constant integral signal. A rule-of-thumb criterion is also derived to instruct the design of the consensus topology that can provide faster convergence rate for the closed-loop system. Here, the stability and convergence improvements developed in this paper are demonstrated and verified through numerical examples.

42 ENGINEERING↗
DOE OSTI2025

Multi-phase Wireless Power Transfer with High Power Density Inductive Coils for Electric Drone Charging

Wireless charging of unmanned ground vehi-cles and aircraft has been proposed to increase charging reliability and security, allow for autonomous functionality, and either reduce battery size or increase continuous flight time. This paper proposes a three-phase Litz wire primary and a two-phase PCB secondary for high secondary-side power density considering misalignment tolerances, surface and volumetric power density, and coil sizing. Elec-tromagnetic 3D finite element analysis (FEA) simulations are conducted to study variation in mutual inductance and coupling coefficient with different secondary coil sizes and number of turns, horizontal and vertical misalignment between the primary and secondary, and a combination of both for a set of designs with the same rated power. Results indicate that receiver coils of reduced size relative to the primary can deliver rated power for increased power density and higher tolerance to misalignment.

Gastineau, Lucas [University of Kentucky]↗
DOE OSTI2024

Power Layout Design of a GaN HEMTs-Based High-Power High-Efficiency Three-Level ANPC Inverter for 800 V DC Bus System

Multiple commutation paths exist for switching devices in a three-level active neutral point clamped (3L-ANPC) inverter operation based on the selected switching state and current direction. In addition, the capacitive coupling path of the nonswitching device is a key design aspect for enabling high voltage and high current operation of gallium nitride (GaN) switches in 3L-ANPC topology. A comprehensive study of the switching transient events of inner, outer, and clamping devices of 3L-ANPC is presented in this article. The commutation mechanisms for worst-case transient voltage overshoots (TVOs) are identified. A simplified equivalent circuit model is presented to determine the design criteria for the power layout structure's parasitic inductances. A power layout strategy satisfying the design criteria is then proposed using an insulated metal substrate power printed circuit board (PCB) to enable efficient high-power operation. The proposed design minimizes the commutation and capacitive coupling path inductances to 6 nH and 11.5 nH, respectively. This enables the fast switching operation of GaN HEMTs at 800 V dc, 36 A with a low TVO of 31% verified through experimental three-level double pulse test results. Experimental evaluation of a three-phase 3L-ANPC hardware prototype based on the proposed power layout shows 99% efficiency at 800 V, 9.5 kVA and 50 kHz switching frequency. The proposed design achieves a low case-to-ambient thermal resistance of 2.3 °C/W.

42 ENGINEERING↗
DOE OSTI2024

On the Use of Tidal Power for Enhancing Power System Resilience with Networked Microgrids

The resilience of a power system to withstand a high-impact low-frequency event is a growing concern, especially in coastal communities that tend to be densely populated and very prone to extreme events such as storms and flooding. In such areas, marine renewable energy can be integrated with the existing renewable energy sources to improve generation diversity and power system resiliency. Using networked microgrids as an example, this paper proposes an empirical study to investigate the impact of marine resources, in particular, tidal energy on the power system resiliency. A set of quantitative metrics with intuitive physical interpretations is used to evaluate the resiliency of a power system that is enhanced with distributed generation in the form of rooftop photovoltaic systems and tidal generators. The effectiveness of resource diversification on the power system resiliency is demonstrated through simulations on a model of a real-world coastal distribution feeder located in Sequim, Washington.

Peerzada, Aaqib A.↗
DOE OSTI2020

Improving power grid transient stability and transfer capability using HVDC emergency power controls

In the future, with high levels of renewable energy sources penetration, the transmission corridors will have to be flexible to operate under faster transients and variable power flows. Fast power ramping and overloading capabilities of HVDC system can be utilized to ensure transient stability of the interconnected power grid. In this paper, HVDC auxiliary controllers have been studied that can provide the power grid with additional synchronizing torques through fast DC power changes in response to arising system conditions. The effectiveness of the auxiliary controllers in improving transient stability is demonstrated by performing dynamic simulations on the detailed model of the Western Interconnection system (WECC).

Sundaresh, Lakshmi↗
DOE OSTI2020

Separating Nuclear Reactors from the Power Block with Heat Storage: A New Power Plant Design Paradigm

The Massachusetts Institute of Technology (MIT), Idaho National Laboratory (INL) and the Electric Power Research Institute (EPRI) conducted a workshop on Separating Nuclear Reactors from the Power Block with Heat Storage: A New Power Plant Design Paradigm. The workshop was held as three webinars (July 29, August 12 and August 26, 2020). These proceedings include this abstract, an executive summary, the main report and presentations. There are two reasons to consider a new design paradigm. First, the market is changing with (1) the addition of variable wind and solar that results in highly volatile electricity prices and (2) the goal of a low-carbon economy that requires (a) economic dispatchable electricity that is now provided by natural gas turbines in the United States and (b) heat for industry and commerce. Second, nuclear plant requirements have changed in the last 50 years suggesting that a lower-cost plant layout may be to separate the nuclear island from the power block with a clear separation of the nuclear island with nuclear requirements and the power block built to industrial standards.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2023

A Power Application Developer’s Guide to the Common Information Model: An Introduction for Power Systems Engineers and Application Developers – CIM17v40

A key issue in creating the next generation of energy management system (EMS) and advanced distribution management system (ADMS) platforms will be the ability to represent and exchange power system network model data in a consistent manner. To this end, the Common Information Model (CIM) stands out as the only standardized vocabulary (or ontology) for defining power system network models and asset data in a comprehensive, consistent manner across the generation-transmission-distribution boundary. The CIM is freely available to use and extend. The CIM is maintained by the UCAiug (informally known as the CIM User’s Group) under an Apache 2.0 license. The CIM Users Group collaborates with the IEC and other standards communities for the development of technical and informative specifications. Although portions of the information model are referred to by the corresponding IEC standards naming, it is not necessary to purchase any of the IEC standards to use the CIM information model. This document provides a roadmap for power system engineers and application developers not familiar with semantic modeling to start using the CIM for modeling, simulation, optimization, and development of advanced power applications. The key classes needed for defining power system topology and equipment are explained systematically. Key focus areas include modeling of lines, transformers, generators, switching equipment, loads, and distributed energy resources (DERs).

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2021

Tritium Betavoltaic Powered Sensor Platforms: Power Augmentation with Scintillating Particles

Betavoltaics (BV) are long-life power sources that typically convert beta particle radiation into electricity. Largely, the radioactive decays within the source go unharvested by the device. This work seeks to augment the power generation of BV devices by integration of scintillating particles within the radiative getter to convert beta emission which would otherwise not leave the getter into usable light for power generation. Silica-covered barium fluoride scintillating particles were integrated into a tritiated water getter. Power generation was increased from 100s of nW to µW levels with the addition of 0.2 wt. % particles into the getter. Nanowatt-scale sensor platforms were demonstrated with the µW BV devices and the maximum possible lifetime of such platforms was estimated. As this technique enables higher power density BV devices from conventional Si semiconductors (compared to wider bandgap BVs), the further implementation may lower the barrier-to-deployment of these long-life power/sensor platforms.

42 ENGINEERING↗
DOE OSTI2019

High-frequency, high-power performance of AlGaN-channel high-electron-mobility transistors: an RF simulation study [High-frequency high power performance of AlGaN channel HEMTs: an RF simulation study]

The emerging Al-rich AlGaN-channel Al x Ga 1–x N/Al y Ga 1–y N high-electron-mobility transistors (HEMTs) with 0.7 ≤ y < x ≤ 1.0 have the potential to greatly exceed the power handling capabilities of today's GaN HEMTs, possibly by five times. This projection is based on the expected 4× enhancement of the critical electric field, the 2× enhancement of sheet carrier density, and the parity of the electron saturation velocity for Al-rich AlGaN-channel HEMTs relative to GaN-channel HEMTs. In this paper, the expected increased RF power density in Al-rich AlGaN-channel HEMTs is calculated by theoretical analysis and computer simulations, based on existing data on long-channel AlGaN devices. It is shown that a saturated power density of 18 W mm –1 , a power-added efficiency of 55% and an output third-order intercept point over 40 dB can be achieved for this technology. Furthermore, the method for large-signal RF performance estimation presented in this paper is generic and can be applied to other novel high-power device technologies at the early stages of development.

42 ENGINEERING↗
NASA NTRS1974

H2-O2 combustion powered steam-MHD central power systems

Estimates are made for both the performance and the power costs of H2-O2 combustion powered steam-MHD central power systems. Hydrogen gas is assumed to be transmitted by pipe from a remote coal gasifier into the city and converted to electricity in a steam MHD plant having an integral gaseous oxygen plant. These steam MHD systems appear to offer an attractive alternative to both in-city clean fueled conventional steam power plants and to remote coal fired power plants with underground electric transmission into the city.

Seikel, G. R.↗
NASA NTRS1974

H2-O2 combustion powered steam-MHD central power systems

Estimates are made for both the performance and the power costs of H2-O2 combustion powered steam-MHD central power systems. Hydrogen gas is assumed to be transmitted by pipe from a remote coal gasifier into the city and converted to electricity in a steam MHD plant having an integral gaseous oxygen plant. These steam MHD systems appear to offer an attractive alternative to both in-city clean fueled conventional steam power plants and to remote coal fired power plants with underground electric transmission into the city.

Seikel, G. R.↗