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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 235 records · Page 13

Space Solar Power Technology Demonstration for Lunar Polar Applications: Laser-Photovoltaic Wireless Power Transmission

Space Solar Power technology offers unique benefits for near-term NASA space science missions, which can mature this technology for other future applications. "Laser-Photo-Voltaic Wireless Power Transmission" (Laser-PV WPT) is a technology that uses a laser to beam power to a photovoltaic receiver, which converts the laser's light into electricity. Future Laser-PV WPT systems may beam power from Earth to satellites or large Space Solar Power satellites may beam power to Earth, perhaps supplementing terrestrial solar photo-voltaic receivers. In a near-term scientific mission to the moon, Laser-PV WPT can enable robotic operations in permanently shadowed lunar polar craters, which may contain ice. Ground-based technology demonstrations are proceeding, to mature the technology for this initial application, in the moon's polar regions.

Henley, M. W.↗

High-Power Krypton Hall Thruster Technology Being Developed for Nuclear-Powered Applications

The NASA Glenn Research Center has been performing research and development of moderate specific impulse, xenon-fueled, high-power Hall thrusters for potential solar electric propulsion applications. These applications include Mars missions, reusable tugs for low-Earth-orbit to geosynchronous-Earth-orbit transportation, and missions that require transportation to libration points. This research and development effort resulted in the design and fabrication of the NASA-457M Hall thruster that has been tested at input powers up to 95 kW. During project year 2003, NASA established Project Prometheus to develop technology in the areas of nuclear power and propulsion, which are enabling for deep-space science missions. One of the Project-Prometheus-sponsored Nuclear Propulsion Research tasks is to investigate alternate propellants for high-power Hall thruster electric propulsion. The motivation for alternate propellants includes the disadvantageous cost and availability of xenon propellant for extremely large scale, xenon-fueled propulsion systems and the potential system performance benefits of using alternate propellants. The alternate propellant krypton was investigated because of its low cost relative to xenon. Krypton propellant also has potential performance benefits for deep-space missions because the theoretical specific impulse for a given voltage is 20 percent higher than for xenon because of krypton's lower molecular weight. During project year 2003, the performance of the high-power NASA-457M Hall thruster was measured using krypton as the propellant at power levels ranging from 6.4 to 72.5 kW. The thrust produced ranged from 0.3 to 2.5 N at a discharge specific impulse up to 4500 sec.

Jacobson, David T.↗

Low Power, High Voltage Power Supply with Fast Rise/Fall Time

A low power, high voltage power supply system includes a high voltage power supply stage and a preregulator for programming the power supply stage so as to produce an output voltage which is a predetermined fraction of a desired voltage level. The power supply stage includes a high voltage, voltage doubler stage connected to receive the output voltage from the preregulator and for, when activated, providing amplification of the output voltage to the desired voltage level. A first feedback loop is connected between the output of the preregulator and an input of the preregulator while a second feedback loop is connected between the output of the power supply stage and the input of the preregulator.

Bearden, Douglas B.↗

Wireless Power Transmission Options for Space Solar Power

Space Solar Power (SSP), combined with Wireless Power Transmission (WPT), offers the far-term potential to solve major energy problems on Earth. In this presentation, two basic WPT options, using radio waves an d light waves, are considered for both long-term and near-term SSP applications. In the long-term, we aspire to beam energy to Earth from geostationary Earth orbit (GEO), or even further distances in space. Accordingly, radio- and light- wave WPT options are compared through a wide range of criteria, each showing certain strengths. In the near-term, we plan to beam power over more moderate distances, but still stretch the limits of today's technology. For the near-term, a 100 kWe-class "Power Plug" Satellite and a 10 kWe-class Lunar Polar Solar Power outpost are considered as the first steps in using these WPT options for SSP. By using SSP and WPT technology in nearterm space science and exploration missions, we gain experience needed for sound decisions in designing and developing larger systems to send power from Space to Earth.

Henley, Mark↗

Low power, high voltage power supply with fast rise/fall time

A low power, high voltage power supply system includes a high voltage power supply stage and a preregulator for programming the power supply stage so as to produce an output voltage which is a predetermined fraction of a desired voltage level. The power supply stage includes a high voltage, voltage doubler stage connected to receive the output voltage from the preregulator and for, when activated, providing amplification of the output voltage to the desired voltage level. A first feedback loop is connected between the output of the preregulator and an input of the preregulator while a second feedback loop is connected between the output of the power supply stage and the input of the preregulator.

Bearden, Douglas B.↗

Fuel-Cell-Powered Vehicle with Hybrid Power Management

Figure 1 depicts a hybrid electric utility vehicle that is powered by hydrogenburning proton-exchange-membrane (PEM) fuel cells operating in conjunction with a metal hydride hydrogen-storage unit. Unlike conventional hybrid electric vehicles, this vehicle utilizes ultracapacitors, rather than batteries, for storing electric energy. This vehicle is a product of continuing efforts to develop the technological discipline known as hybrid power management (HPM), which is oriented toward integration of diverse electric energy-generating, energy-storing, and energy- consuming devices in optimal configurations. Instances of HPM were reported in five prior NASA Tech Briefs articles, though not explicitly labeled as HPM in the first three articles: "Ultracapacitors Store Energy in a Hybrid Electric Vehicle" (LEW-16876), Vol. 24, No. 4 (April 2000), page 63; "Photovoltaic Power Station With Ultracapacitors for Storage" (LEW- 17177), Vol. 27, No. 8 (August 2003), page 38; "Flasher Powered by Photovoltaic Cells and Ultracapacitors" (LEW-17246), Vol. 27, No. 10 (October 2003), page 37; "Hybrid Power Management" (LEW-17520), Vol. 29, No. 12 (December 2005), page 35; and "Ultracapacitor-Powered Cordless Drill" (LEW-18116-1), Vol. 31, No. 8 (August 2007), page 34. To recapitulate from the cited prior articles: The use of ultracapacitors as energy- storage devices lies at the heart of HPM. An ultracapacitor is an electrochemical energy-storage device, but unlike in a conventional rechargeable electrochemical cell or battery, chemical reactions do not take place during operation. Instead, energy is stored electrostatically at an electrode/electrolyte interface. The capacitance per unit volume of an ultracapacitor is much greater than that of a conventional capacitor because its electrodes have much greater surface area per unit volume and the separation between the electrodes is much smaller.

Eichenberg, Dennis J.↗

On-Chip Power-Combining for High-Power Schottky Diode-Based Frequency Multipliers

A 1.6-THz power-combined Schottky frequency tripler was designed to handle approximately 30 mW input power. The design of Schottky-based triplers at this frequency range is mainly constrained by the shrinkage of the waveguide dimensions with frequency and the minimum diode mesa sizes, which limits the maximum number of diodes that can be placed on the chip to no more than two. Hence, multiple-chip power-combined schemes become necessary to increase the power-handling capabilities of high-frequency multipliers. The design presented here overcomes difficulties by performing the power-combining directly on-chip. Four E-probes are located at a single input waveguide in order to equally pump four multiplying structures (featuring two diodes each). The produced output power is then recombined at the output using the same concept.

Chattopadhyay, Goutam↗

A Comparison Of A Solar Power Satellite Concept To A Concentrating Solar Power System

A comparison is made of a Solar Power Satellite concept in geostationary Earth orbit to a Concentrating Solar Power system on the ground to analyze overall efficiencies of each infrastructure from solar radiance at 1 AU to conversion and transmission of electrical energy into the power grid on the Earth's surface. Each system is sized for a 1-gigawatt output to the power grid and then further analyzed to determine primary collector infrastructure areas. Findings indicate that even though the Solar Power Satellite concept has a higher end-to-end efficiency, that the combined space and ground collector infrastructure is still about the same size as a comparable Concentrating Solar Power system on the ground.

Smitherman, David V.↗

Long-Term Reliability of a Hard-Switched Boost Power Processing Unit Utilizing SiC Power MOSFETs

Silicon carbide (SiC) power devices have demonstrated many performance advantages over their silicon (Si) counterparts. As the inherent material limitations of Si devices are being swiftly realized, wide-band-gap (WBG) materials such as SiC have become increasingly attractive for high power applications. In particular, SiC power metal oxide semiconductor field effect transistors' (MOSFETs) high breakdown field tolerance, superior thermal conductivity and low-resistivity drift regions make these devices an excellent candidate for power dense, low loss, high frequency switching applications in extreme environment conditions. In this paper, a novel power processing unit (PPU) architecture is proposed utilizing commercially available 4H-SiC power MOSFETs from CREE Inc. A multiphase straight boost converter topology is implemented to supply up to 10 kilowatts full-scale. High Temperature Gate Bias (HTGB) and High Temperature Reverse Bias (HTRB) characterization is performed to evaluate the long-term reliability of both the gate oxide and the body diode of the SiC components. Finally, susceptibility of the CREE SiC MOSFETs to damaging effects from heavy-ion radiation representative of the on-orbit galactic cosmic ray environment are explored. The results provide the baseline performance metrics of operation as well as demonstrate the feasibility of a hard-switched PPU in harsh environments.

Ikpe, Stanley A.↗

Power Quality and Stability in a Cluster of Microgrids with Coordinated Power and Energy Management

Distributed Energy Resources (DER) such as photovoltaic (PV) systems and battery energy storage systems (BESS) can be operated collectively as microgrids. Microgrids can be effective in meeting local load requirements as well as in improving the power quality and stability in a modern power distribution system. Multiple microgrids can also be operated in a coordinated manner as a cluster, to improve the resiliency of the power distribution system. In the event of an outage caused by a transmission system failure, the microgrids in a cluster can use their distributed generation capacity and energy storage resources to recover and extend power availability to the critical loads in the system. In this paper, an illustrative cluster of two microgrids based on the IEEE 13-bus model with DERs has been used, to demonstrate the operation of the concept using real-time simulations. Using real-time simulations, capabilities such as switching reconfiguration following faults, identification of optimal DER placement for effective power quality management, and power electronic controller validation have been demonstrated. For the two-microgrid cluster, this paper also presents improvements in load voltage quality and

Chowdhury, Prithwiraj Roy↗

Load following power generation and power storage using REP and PEM technology

A hydrogen generation system for generating hydrogen and electrical power includes a power supply, a reformer-electrolyzer-purifier (REP) assembly including at least one fuel cell including an anode and a cathode separated by an electrolyte matrix, at least one low temperature fuel cell, and a hydrogen storage. The at least one fuel cell is configured to receive a reverse voltage supplied by the power supply and generate hydrogen-containing gas in the anode of the at least one fuel cell. The at least one low temperature fuel cell is configured to receive the hydrogen-containing gas output from the REP assembly. The at least one low temperature fuel cell is configured to selectably operate in a power generation mode in which the hydrogen-containing gas is used to generate electrical power and a power storage mode in which the hydrogen-containing gas is pressurized and stored in the hydrogen storage.

Jahnke, Fred C.↗

Fluid power circuit having switch-mode power transformer and methods

A fluid power circuit with a switch-mode power transformer used to transfer power while keeping the pressure of power source and reverse osmosis processes relatively decoupled. The switch-mode power transformer uses the inertia of a hydraulic motor driven electric generator and switching of a hydraulic motor inlet between high and low-pressure ends to decrease the pressure at which power is being transmitted to a reverse osmosis process.

Simmons, II, Jeremy W.↗

Fiber-Shaped Fluidic Nanogenerator with High Power Density for Self-Powered Integrated Electronics

Flow-based hydrovoltaic nanogenerators have attracted particular attention as efficient and facile miniature energy-harvesting devices. However, they deliver relatively low output power density and limited power conversion efficiency owing to inefficient charge separation and poor charge accumulation. Here, we report the fabrication of high-performance, fiber-shaped fluidic nanogenerators (FFNGs) that use MoS 2 -encapsulated C fibers. The FFNGs deliver stable output voltages of 540 mV and an ultrahigh power density of 10.8 W m -2 . With experiments and density functional theory calculations, improvements in output performance can be attributed to smaller energy requirements for Na + cation adsorption, increased charge separation, and diffusion layer formations on the near surface. Moreover, self-powered, integrated devices achieve a maximum total power conversion-storage efficiency of ~11% and stable output voltage up to 3.1 V, which is applicable for use in consumer electronics devices.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Conformal High-Power-Density Half-Heusler Thermoelectric Modules: A Pathway toward Practical Power Generators

Thermoelectric generators (TEGs) exploiting the Seebeck effect provide a promising solution for waste heat recovery. Among the large number of thermoelectric (TE) materials, half-Heusler (hH) alloys are leading candidates for medium- to high-temperature power generation applications. However, the fundamental challenge in this field has been inhomogeneous material properties at large wafer diameters, insufficient power output from the modules, and rigid form factors of TE modules. This has restricted the transition of TEGs in practical applications for over three decades. Here, we successfully demonstrate large diameter wafers with uniform TE properties, high-power conformal hH TE modules for high-temperature application, and their direct integration on flue gas platforms, such as cylindrical tubes, to form large area flexible TEGs. This new conformal architecture design provides a breakthrough toward medium-/high-temperature TEGs over the conventional BiTe- and polymer-based flexible TEG design. In this work, a variable fill factor and greater flexibility due to the conformal design result in higher device performance as compared to conventional rigid TEG devices. Modules with 72-couple hH legs exhibit a device high-power-density of 3.13 W cm-2 and a total output power of 56.6 W under a temperature difference of 570 degrees C. These results provide a promising pathway toward widespread utilization of thermoelectric technology into the waste heat recovery application and will have a significant impact on the development of practical thermal to electrical converters.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Effects of Reactive Power on Photovoltaic Inverter Reliability and Lifetime

This paper performs research on predicting Photovoltaic (PV) inverters reliability and lifetime based on thermal cycling. Thermal cycling is considered the most important stressors in an inverter system. In order to achieve this, a detailed electro-thermal model of the PV inverter will be developed along with their controllers capable of providing voltage support through reactive power. An in-house inverter was built, and a PV inverter model was developed to match the physical inverter. The PV inverter electrothermal model was validated for different ambient temperatures to match the in-house inverter hardware. The in-house inverter was placed inside a thermal chamber to emulate different ambient temperatures and their losses and temperature rises within the system were measured. After the validation of the model, a reduced order model of the inverter will be implemented to translate the mission profile of ambient temperature and solar irradiance into load profile of junction temperatures of the switches. The junction temperature data will be used to identify the reliability indices and hence predict the useful lifetime of the inverter system. Along with the model to predict useful lifetime of the system, the impact of reactive power on the overall reliability of the system will be studied. The key observation in this paper shows that lifetime of the inverter decreases as the operating power factor moves away from unity.

14 SOLAR ENERGY↗

Power HIL Evaluation of Inverter Controls for 100% Inverter-Based Bulk Power Systems

NREL's Power Electronic Grid Interface (PEGI) Workshop, held October 13, 2020, focused on the research challenges of operating power systems with ever-higher levels of inverter-based generation and power-electronic-based load. This presentation discusses a power hardware-in-the-loop evaluation of inverter controls for 100% inverter-based bulk power systems.

grid integration↗

Wildfire-Power Grid Interactions: Feedback, Impacts, Monitoring, Modeling, and Mitigation Strategies

Wildfires are increasingly interacting with electric power systems through a two-way hazard chain: fires damage grid assets and trigger cascading outages, while grid faults can ignite new fires under hot, dry, and windy conditions. This review synthesizes the state of knowledge across five domains: (i) physical impacts of flames, heat, and smoke on lines, towers, insulators, and substations; (ii) power-infrastructure-initiated ignitions via conductor clash, high-impedance faults, and corona discharge; (iii) widespread blackouts and disproportionate societal impacts; (iv) multi-scale monitoring spanning laboratory tests, in-situ and grid-integrated sensors, and Earth observation; (v) coupled modeling that links fire behavior with grid operations; and (vi) technological and strategic mitigation pathways spanning prevention, response, and recovery. We integrate these domains into a novel 'feedback-aware' socio-technical framework. Through a longitudinal analysis (2005-2025) of global incidents, we identify that while vegetation contact remains the most frequent ignition source, aging infrastructure failure has emerged as a critical driver of catastrophic 'mega-fires'. We further identify persistent gaps, including limited interoperability of high-frequency grid and environmental data, scarce real-time data assimilation, and under-developed equity metrics for outage management. We conclude by outlining a research agenda to (1) deploy interoperable sensing architectures, (2) advance feedback-coupled fire-grid simulations, and (3) evaluate mitigation portfolios through techno-economic and fairness lenses. Recognizing wildfire-grid interactions as coupled socio-technical systems is essential for protecting infrastructure and communities and for ensuring reliable, sustainable electricity in a changing world.

24 POWER TRANSMISSION AND DISTRIBUTION↗