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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 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Defining a Platform Approach and Market Participation: Data Driven Business Models for Solid State Transformer-Based Synthetic Inertia and Voltage Stability Controls (CRADA Final Report, Project 1, Mod 1)

The primary objective of this project is to determine the incremental value created with the medium voltage solid-state transformer (MV SST) technology to different stakeholders in view of the updated DER grid regulations. This includes studying the benefits of the MV SST technology in a range of use cases for EV and DER penetration including (1) “corridor charging” for EVs and (2) solar plus storage (FERC 2222). The potential customers of this technology include utilities for EV charging, DER installers who must meet utility interconnection requirements, balancing authorities, and DER aggregators. The traditional transformers on the grid could be a limiting factor for the EV-grid integration as the distribution transformers were not designed to handle the dynamic and fluctuating EV charging loads. Thus, the issues such as voltage fluctuations, increased losses and reduced efficiency [1] can negatively impact the grid operation. To address these challenges, transformers with flexibility and adaptability become imperative to meet the evolving energy demands. In this regard, the concept of Medium Voltage Solid-State Transformers.

14 SOLAR ENERGY↗
DOE OSTI2021

Testing the DIII-D co/counter off-axis neutral beam injected power and ability to balance injected torque

DIII-D has undergone a major upgrade and successfully injected high power off-axis neutral beams (~4 MW) in both co-current and counter-current directions. This capability of high power co/counter steerable off-axis neutral beams on a major tokamak opens a unique parameter space of broad pressure and current profiles for high beta steady-state advanced tokamak (AT) scenarios, while retaining the ability to balance the injected torque for low rotation studies. This co/counter off-axis neutral beam capability is being used to validate physics-based energetic particle and thermal transport models for designing next-step facilities based on the steady-state AT approach. This paper reports on the critical evaluation of the transmitted power and energetic ion population produced by this heating and current drive system, which is assessed through visible imaging, neutron measurements and rotation profile measurements at balanced torque. Minimal losses of neutral beam power have been achieved by optimizing the strongly focused ion sources required to pass through the aperture. Tilting of the ion source has been guided by fast visible imaging and resulted in neutral beam injection along the design centerline with empirical characterization of each beam's divergence derived from the imaging data and used in the NUBEAM description of the beam injection. Through exclusive power injection of each neutral beam into MHD quiescent plasmas across a range of neutral beam voltage, perveance and plasma current we conclude that a modest reduction (~10%–15%) of transmitted power compared to on-axis, standard focus has been incurred. We report corrections that more accurately represent the injected power. Good ability to balance the neutral beam torque has been demonstrated by injecting the new off-axis counter injecting beam against the existing off-axis co-injected beam in 2.0 T, 1.0 MA, MHD quiescent L-mode plasmas. Furthermore, the torque balance studies verify the ability to operate with balanced injection, which is critical for achieving low torque and low rotation operation for physics studies and in ITER demonstration discharges.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
NASA NTRS2012

Small Radioisotope Power System at NASA Glenn Research Center

In April 2009, NASA Glenn Research Center (GRC) formed an integrated product team (IPT) to develop a Small Radioisotope Power System (SRPS) utilizing a single Advanced Stirling Convertor (ASC) with passive balancer for possible use by the International Lunar Network (ILN) program. The ILN program is studying the feasibility of implementing a multiple node seismometer network to investigate the internal lunar structure. A single ASC produces approximately 80 W(sub e) and could potentially supply sufficient power for that application. The IPT consists of Sunpower, Inc., to provide the single ASC with balancer, The Johns Hopkins University Applied Physics Laboratory (JHU/APL) to design an engineering model Single Convertor Controller (SCC) for an ASC with balancer, and NASA GRC to provide technical support to these tasks and to develop a simulated lunar lander test stand. A controller maintains stable operation of an ASC. It regulates the alternating current produced by the linear alternator of the convertor, provides a specified output voltage, and maintains operation at a steady piston amplitude and hot end temperature. JHU/APL also designed an ASC dynamic engine/alternator simulator to aid in the testing and troubleshooting of the SCC. This paper describes the requirements, design, and development of the SCC, including some of the key challenges and the solutions chosen to overcome those issues. In addition, it describes the plans to analyze the effectiveness of a passive balancer to minimize vibration from the ASC, characterize the effect of ASC vibration on a lunar lander, characterize the performance of the SCC, and integrate the single ASC, SCC, and lunar lander test stand to characterize performance of the overall system.

Dugala, Gina M.↗
NASA NTRS1971

Voltage regulator dissipates minimal power and functions as a voltage divider

Regulator requires minimum amount of power for voltage division and it is not required continuously. The only power loss, except for regulating purposes, is that needed to provide for imbalances in load current requirements. For balanced loads, only leakage current flows through regulating transistors.

Hester, H. B.↗
NASA NTRS1980

Improvement and scale-up of the NASA Redox storage system

A preprototype full-function 1.0 kW Redox system (2 kW peak) with 11 kW storage capacity has been built and integrated with the NASA/DOE photovoltaic test facility. The system includes four substacks of 39 cells each (1/3 sq ft active area) which are connected hydraulically in parallel and electrically in series. An open circuit voltage cell and a set of rebalance cells are used to continuously monitor the system state of charge and automatically maintain the anode and cathode reactants electrochemically in balance. Technological advances in membrane and electrodes and results of multicell stack tests are reviewed.

Reid, M. A.↗
NASA NTRS1980

Improvement and scale-up of the NASA Redox storage system

A preprototype 1.0 kW redox system (2 kW peak) with 11 kWh storage capacity was built and integrated with the NASA/DOE photovoltaic test facility at NASA Lewis. This full function redox system includes four substacks of 39 cells each (1/3 cu ft active area) which are connected hydraulically in parallel and electrically in series. An open circuit voltage cell and a set of rebalance cells are used to continuously monitor the system state of charge and automatically maintain the anode and cathode reactants electrochemically in balance. Recent membrane and electrode advances are summarized and the results of multicell stack tests of 1 cu ft are described.

Reid, M. A.↗
NASA NTRS1992

Nickel hydrogen common pressure vessel battery development

Our present design for a common pressure vessel (CPV) battery, a nickel hydrogen battery system to combine all of the cells into a common pressure vessel, uses an open disk which allows the cell to be set into a shallow cavity; subsequent cells are stacked on each other with the total number based on the battery voltage required. This approach not only eliminates the assembly error threat, but also more readily assures equal contact pressure to the heat fin between each cell, which further assures balanced heat transfer. These heat fin dishes with their appropriate cell stacks are held together with tie bars which in turn are connected to the pressure vessel weld rings at each end of the tube.

Jones, Kenneth R.↗
NASA NTRS1992

The modeling of piezoceramic patch interactions with shells, plates and beams

General models describing the interactions between a pair of piezoceramic patches and elastic substructures consisting of a cylindrical shell, plate and beam are presented. In each case, the manner in which the patch loads enter both the strong and weak forms of the time-dependent structural equations of motion is described. Through force and moment balancing, these loads are then determined in terms of material properties of the patch and substructure (thickness, elastic properties, Poisson ratios), the geometry of the patch placement, and the voltages into the patches. In the case of the shell, the coupling between banding and inplane deformations, which is due to the curvature, is retained. These models are sufficiently general to allow for potentially different patch voltages which implies that they can be suitably employed when using piezoceramic patches for controlling system dynamics when both extensional and bending vibrations are present.

Banks, H. T.↗
DOE OSTI2025

Cross-scale modeling and experimental integration for advancing cathode electrolyte interphase studies in high energy density lithium-ion batteries

Electrochemical interfaces are critical to the performance and durability of lithium-ion batteries (LIBs). The solid electrode-electrolyte interphase (SEI and CEI) structures that form during cycling can passivate reactive surfaces, ensuring safe operation, but also may contribute to performance degradation. Understanding the microscopic factors influencing interphase formation, growth, and evolution is essential for balanced battery design. While significant research has focused on the anode-electrolyte interphase (SEI), the cathode-electrolyte interphase (CEI) remains less explored, despite its importance in high-voltage and advanced battery technologies. Challenges in conducting in-situ or operando experiments arise from the occluded nature of these interfaces and the long timescales involved, often leading to biased interpretations. A validated multi-scale, multi-physics modeling approach, integrated with advanced characterization techniques, can effectively elucidate the intrinsic stability of electrolyte and cathode surfaces, the impact of chemical heterogeneity, and the role of microstructural features on CEI performance. In conclusion, this article reviews current modeling and simulation strategies for studying CEI in advanced LIBs and highlights opportunities for future methodological advancements and experimental integration.

Cathode-electrolyte interphase↗
NASA NTRS1984

Requirements for a transformerless power conditioning system

Requirements for development of a Transformerless Power Conditioning Subsystem (TPCS) that will meet utility, manufacturer, and customer needs are detailed. Issues analyzed include current utility guidelines, safety and grounding issues that appear as local codes, various kinds of TPCS connections that can be developed, dc injection, and a brief survey of TPCS circuit topologies that will meet requirements. The major result is that a finite time exists for control operation before dc injection into the distribution transformer causes customer outage (on the order of seconds). This time permits the control system to sense a dc injection condition and remove the TPCS from the utility system. Requirements for such a control system are specified. A three wire connection will ensure balanced operation for customer loads and two wire connections caused average value dc to be injected into single phase loads. This type of connection also allows for the lowest array voltage. The conclusion is that requirements for a TPCS can be determined and that there are not showstopping issues preventing implementation. The actual design and topology of the TPCS was left for further study.

Klein, J.↗
DOE OSTI2025

Feedforward equilibrium trajectory optimization with GSPulse

One of the common tasks required for designing new plasma scenarios or evaluating capabilities of a tokamak is to design the desired equilibria using a Grad-Shafranov (GS) equilibrium solver. However, most standard equilibrium solvers are time-independent and do not include dynamic effects such as plasma current flux consumption, induced vessel currents, or voltage constraints. Another class of tools, plasma equilibrium evolution simulators, do include time-dependent effects. These are generally structured to solve the forward problem of evolving the plasma equilibrium given feedback-controlled voltages. In this work, we introduce GSPulse, a novel algorithm for equilibrium trajectory optimization, that is more akin to a pulse planner than a pulse simulator. GSPulse includes time-dependent effects and solves the inverse problem: given a user-specified set of target equilibrium shapes, as well as limits on the coil currents and voltages, the optimizer returns trajectories of the voltages, currents, and achievable equilibria. This task is useful for scoping performance of a tokamak and exploring the space of achievable pulses. The computed equilibria satisfy both Grad-Shafranov force balance and axisymmetric circuit dynamics. The optimization is performed by restructuring the free-boundary equilibrium evolution equations into a form where it is computationally efficient to optimize the entire dynamic sequence. GSPulse can solve for hundreds of equilibria simultaneously within a few minutes. GSPulse has been validated against NSTX-U and MAST-U experiments and against SPARC feedback control simulations, and is being used to perform scenario design for SPARC. The computed trajectories can be used as feedforward inputs that are connected to the feedback controller to inform and improve feedback performance. The code for GSPulse is available open-source at github.com/jwai-cfs/GSPulse_public.

equilibrium↗
NASA NTRS1982

The flexible magnetic field thruster

The thruster is designed so that ion currents to various internal surfaces can be measured directly; these measurements facilitate calculations of the distribution of ion currents inside the discharge chamber. Experiments are described suggesting that the distribution of ion currents inside the discharge chamber is strongly dependent on the shape and strength of the magnetic field but independent of the discharge current, discharge voltage, and neutral flow rate. Measurements of the energy cost per plasma ion suggest that this cost decreases with increasing magnetic field strength as a consequence of increased anode shielding from the primary electrons. Energy costs per argon plasma ion as low as 50 eV are measured. The energy cost per beam ion is found to be a function of the energy cost per plasma ion, extracted ion fraction, and discharge voltage. Part of the energy cost per beam ion has to do with creating many ions in the plasma and then extracting only a fraction of them into the beam. The balance of the energy goes into accelerating the remaining plasma ions into the walls of the discharge chamber.

Brophy, J. R.↗
NASA NTRS1992

Electrical breakdown of Space Station Freedom surfaces

Space Station Freedom (SSF) will be the largest and highest power spacecraft that the U.S. has put into orbit. The solar array will generate 160 volts nominal when in sunlight, and the present baseline design is for the negative end of the solar array to be tied to SSF structure. Due to the balance of leakage currents through the plasma, the structure will be driven approximately 140 volts negative of the ambient conductive ionospheric plasma. Surface materials such as anodized aluminum will have this voltage drop across a thin dielectric which may not have sufficient dielectric strength to prevent dielectric breakdown. This can lead to arcing on the exterior surfaces of Space Station.

Carruth, M. R., Jr.↗
NASA NTRS1995

Active Pyroelectric Infrared Detector

A noncontact pyroelectric infrared detector is described. A pyroelectric film that also has piezoelectric properties is held in place so that it is free to vibrate. It is electrically stimulated to vibrate at a resonance frequency. The vibrating film forms part of a balanced bridge circuit. As thermal radiation impinges on the film the pyroelectric effect causes the resonance frequency to change, thereby unbalancing the bridge circuit. A differential amplifier tracks the change in voltage across the bridge. The resulting voltage signal is further processed by a bandpass filter and a precision rectifier. The device allows for DC or static temperature measurements without the use of a mechanical chopping device.

Zuckerwar, Allan J.↗
DOE OSTI2025

Parasitic structure defect blights sustainability of cobalt-free single crystalline cathodes

Abstract Recent efforts to reduce battery costs and enhance sustainability have focused on eliminating Cobalt (Co) from cathode materials. While Co-free designs have shown notable success in polycrystalline cathodes, their impact on single crystalline (SC) cathodes remains less understood due to the significantly extended lithium diffusion pathways and the higher-temperature synthesis involved. Here, we reveal that removing Co from SC cathodes is structurally and electrochemically unfavorable, exhibiting unusual voltage fade behavior. Using multiscale diffraction and imaging techniques, we identify lithium-rich nanodomains (LRNDs) as a heterogeneous phase within the layered structure of Co-free SC cathodes. These LRNDs act as critical tipping points, inducing significant chemo-mechanical lattice strain and irreversible structural degradation, which exacerbates the voltage and capacity loss in electrochemical performance. Our findings highlight the considerable challenges of developing Co-free SC cathodes compared to polycrystalline ones and emphasize the need for new strategies to balance the interplay between cost, sustainability, and performance.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Experimental Demonstration of Charge-Balanced GaN Super-Heterojunction Schottky Barrier Diode Capable of 2.8 kV Switching

This letter reports an experimental demonstration of charge-balanced GaN super-heterojunction Schottky barrier diodes (SHJ-SBDs). Charge balance between the n-type delta-doping and the p-type doping was achieved by adjusting the thickness of the pGaN. Furthermore, this device structure enabled scaling of breakdown voltage to over 3 kV, and dynamic switching up to 2.8 kV without using any field-plate.

42 ENGINEERING↗
DOE OSTI2025

Sizing and Location Selection of Medium‐Voltage Back‐to‐Back Converters for DER‐Dominated Distribution Systems

Medium‐voltage back‐to‐back (MVB2B) converters can connect two distribution systems and quantifiably transfer power between them. This function can enable the MVB2B converter to exchange distributed energy resource (DER)‐generated power between two systems and bring significant value to enhancing distribution system DER adoption. Our previous work analysed and demonstrated the value MVB2B converter can bring to DER integration. As continuous work, this paper presents a methodology that helps address the MVB2B converter sizing and location selection problem in distribution systems with high DER penetrations. The proposed methodology aims to address three critical problems for MVB2B converter implementation in the real world: (1) which distribution systems are better to be connected, (2) what converter size is appropriate for connecting the distribution systems, and (3) where the optimal connection points are in the systems for connecting the MVB2B converter. The proposed methodology has been demonstrated by case studies that include various scenarios involving distribution systems with different dominated load types and high photovoltaic penetrations. The results demonstrate that selecting the optimal converter size based on net revenue and time of return considerations leads to a balance between maximizing energy savings and minimizing financial payback periods. Furthermore, feeder pair selection based on load profile standard deviation effectively identifies systems that derive the greatest value from MVB2B integration. Finally, an optimized connection point selection approach using a voltage load sensitivity matrix ensures minimal system impact while facilitating efficient power exchange. These findings provide practical insights for the real‐world deployment of MVB2B converters to enhance DER hosting capacity and improve grid resilience.

14 SOLAR ENERGY↗
DOE OSTI2020

15.9% organic tandem solar cell with extended near-infrared absorption

Stacking single-junction organic solar cells is effective in increasing the power conversion efficiency (PCE) by reducing the thermalization loss and increasing the open circuit voltage. Current developments of non-fullerene acceptors (NFAs) offer a range of materials whose energy gaps are suited for absorbing relatively narrow slices of the solar spectrum, thus easing requirements for current balance between sub-elements in the multijunction stacks. In this report, we demonstrate a solution-processed tandem organic solar cell comprising a binary, visible-absorbing sub-cell and a ternary near-infrared (NIR) absorbing sub-cell. The ternary NIR sub-cell utilizes a narrow energy gap NFA acceptor that enables a broadened and increased absorption compared to a binary NIR sub-cell. An isopropanol surface treatment is developed to connect the hydrophilichydrophobic surfaces in the charge recombination zone (CRZ) located between the sub-cells. The nearly optically and electrically lossless CRZ combined with an anti-reflection coating results in a tandem OPV with PCE = 15.9 ± 0.2 % under AM 1.5G simulated illumination.

14 SOLAR ENERGY↗