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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 721 records · Page 40
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Sensitivity of ultralight axion dark matter search with optical quantum sensors

An optical quantum sensor (OQS) based on lasers and alkali-metal atoms is a sensitive ambient-temperature magnetometer that can be used in axion dark matter search with an inductor-capacitor (LC) circuit at kHz and MHz frequencies. We have previously investigated the sensitivity of an LC circuit-OQS axion detector to ultralight axion dark matter that could be achieved using a fT-noise OQS constructed in our lab. In this paper, we investigate the sensitivity that could be potentially reached by an OQS performing close to the fundamental quantum noise levels of 10 aT / $\sqrt{Hz}$. To take advantage of the quantum-limited OQS, the LC circuit has to be made of a superconductor and cooled to low temperature of a few K. After considering the intrinsic noise of the advanced axion detector and characterizing possible background noises, we estimate that such an experiment could probe benchmark QCD axion models in an unexplored mass range near 10 neV. Reaching such a high sensitivity is a difficult task, so we have conducted some preliminary experiments with a large-bore magnet and a prototype axion detector consisting of a room-temperature LC circuit and a commercial OQS unit. In conclusion, this paper describes the prototype experiment and its projected sensitivity to axions in detail.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2025

High-performance permanent-magnet materials based on CeFe 12

We perform first-principles calculations on the Mo/Zr-alloyed ThMn 12 -structure prototype CeFe 12 to explore its electronic and magnetic properties and potential for permanent magnet applications. A recent experiment has shown that the Mo/Zr-alloyed CeFe 12 phase with the symmetry 𝐼⁢4/𝑚⁢𝑚⁢𝑚 can be stabilized in bulk. It encourages an investigation into the intrinsic magnetic characteristics of the base structure CeFe 12 and the effect of transition metal alloying in it. Our calculations reveal that the base structure prototype CeFe 12 in its tetragonal phase exhibits uniaxial magnetic anisotropy with a magnetic anisotropy energy (𝐾 1 ) ∼ 1 MJ/m −3 and a substantial magnetic moment of ∼ 1.8T, showing its promise as a permanent magnet. The introduction of the stabilizing transition metals Zr, Mo, and W reduces these values but still keeps the materials very promising. Notably, when 50% of Ce is substituted by Sm in Mo-alloyed CeFe 12 , the 𝐾 1 is significantly enhanced, accompanied by a fairly decent magnetic moment of ∼ 1.2T. These findings establish this alloy as a strong candidate for high-performance permanent magnet applications. In conclusion, this study emphasizes the importance of strategic element substitution and site selection in transition metal-alloyed CeFe 12 to achieve both structural stability and remarkable magnetic properties.

Density of states↗
DOE OSTI2026

Evaluation of an event-driven 3FI ASIC for spectroscopic X-ray detection with synchrotron radiation

The novel design and evaluation on the NSLS-II beamline of the 3FI application-specific integrated circuit (ASIC) bump-bonded to a simple, planar, 2D segmented silicon sensor are presented. The ASIC was developed for full-field fluorescence spectral X-ray imaging (3FI). It is a small-scale prototype that features a square array of 32 × 32 pixels, and the size of the pixels is 100 µm × 100 µm. The ASIC was implemented in a 65 nm CMOS integrated circuit fabrication process. Each pixel incorporates a charge-sensitive amplifier, a shaping filter, a discriminator, a peak detector and a sample-and-hold circuit, allowing detection of events and storage of signal amplitudes. The system operates in a frameless event-driven readout mode, outputting analog values for threshold-triggered events, allowing high-speed multi-element X-ray fluorescence data acquisition. The 3FI ASIC achieves per-channel spectrometric performance at a power consumption of only 200 µW per pixel, with nearly all dissipation confined to the analog front-end. An energy resolution is measured at the level of 308 eV full width at half-maximum (FWHM) at 8.04 keV (Cu Kα), and 138 eV FWHM at 3.69 keV (Ca Kα). This per-pixel capability makes the prototype suitable for in situ trace element microanalysis in biological and environmental studies. Moreover, the frameless architecture of the detector is designed to address limitations of conventional X-ray fluorescence microscopy, which typically requires mechanical scanning, by enabling continuous high-throughput data acquisition in future full-field implementations.

47 OTHER INSTRUMENTATION↗
DOE OSTI2020

Soft Switching Over the Entire Line Cycle for a Quadruple Active Bridge DCX in a DC to Three-Phase AC Module

This paper is focused on a transformer-isolated quadruple active bridge (QAB) dc-dc converter loaded by three full-bridge dc-ac inverters. The QAB functions as a "DC trans-former" (DCX) in the dc-to-three-phase ac module. The QAB outputs provide time-varying power at twice the line frequency, which presents challenges in maintaining zero voltage switching (ZVS) on the secondary sides during low-power portions of the line cycle. It is shown how ZVS can be achieved in a phase, even at zero-power transfer, using a relatively small circulating current provided by the magnetizing inductance of the high-frequency transformer. The approach is particularly effective in high-voltage applications using SiC MOSFETs, where reductions in switching loss outweigh additional conduction losses due to the circulating currents. A detailed analysis of ZVS switching waveforms at the zero power transfer is presented, including effects of nonlinear device capacitances. Analytical expressions are given for the optimal values of the magnetizing inductance and dead times of the QAB primary and secondary bridges. The approach is verified by experimental results on a 600 V, 4 kW prototype, demonstrating greater than 98.5% efficiency from 1 kW to 4 kW, with a peak efficiency of 99.0%. Compared to conventionally operated prototype, a 54% reduction in total loss is achieved at rated power.

41 EE - Solar Energy Technologies Office (EE-4S)↗
DOE OSTI2021

Three-Phase LCC-LCC Compensated 50-kW Wireless Charging System with Non-Zero Interphase Coupling

In this paper, an LCC-LCC compensated 50 kW 3phase (3φ) wireless charging system with nonzero interphase mutual inductance is demonstrated. The 3φ-LCC compensation is designed considering a nonzero mutual-inductance among the phase-coils to meet resonance criteria, balance voltages and currents of the resonant tank components, achieve desired voltage gain, and ensure the zero-voltage switching (ZVS) operation. An experimental prototype of the 3φ-LCC-LCC compensation circuit is built for a 50 kW bipolar coil-based 3φ wireless charging system. The prototype system was tested at rated 50 kW power for evaluating the efficiency, ZVS operation, electric and magnetic field emissions, and thermal characteristics. The experimental results show 94.3% dc-to-dc efficiency and only 4.4 μT rms magnetic field emission at the rated 50 kW output power.

Mohammad, Mostak↗
DOE OSTI2024

A Multi-Metrics In Situ Aging Detector for SiC Power MOSFET Modules with Full Driver-Integration Capability

In this paper, the concept and prototype of an aging detector for silicon carbide (SiC) power metal oxide semiconductor field effect transistor (MOSFET) are proposed and described. It leverages the resonant peak values of gate-source voltage at different instants during the switching transients to decode the change of multiple aging indicators, such as the increases of on-state resistance and threshold voltage. Modeling-based analysis is conducted to support the idea. The detector can be fully integrated into gate drivers without any additional connection to the power stage and is functional during normal power stage operation. A prototype unit was built, and preliminary tests were conducted to validate the idea and the practicality of the detector.

aging↗
DOE OSTI2026

Experimental Results for an Inverter Integrated with A High-Speed Surface Permanent Magnet External Rotor Motor

This work presents the prototyping and testing of a high-speed outer rotor surface permanent magnet motor. The motor employs non-heavy rare-earth permanent magnets and operates at a rated speed of 6,666 rpm. In-slot ceramic heat exchangers are used to cool the windings. The external rotor configuration provides substantial space within the stator bore, which is used for power electronics integration. This integration introduces several design and thermal management challenges that are discussed in the paper. The machine has been prototyped and tested under various operating conditions, and both simulation and experimental results are presented.

Rallabandi, Vandana [ORNL] (ORCID:0000000236241901↗
DOE OSTI2021

Novel Transformer with Variable Leakage and Magnetizing Inductances

This paper introduces the concept of a novel variable inductance transformer (VIT) whose leakage and magnetizing inductances can be varied dynamically and independently to aid the advancement of research in isolated power electronic converters. In this transformer, the leakage inductance can be varied by varying the length of overlap between the primary and secondary windings, while the magnetizing inductance can be varied by varying the air gap between the core legs. Individual controls for the two inductances ensure that one can be varied independent of the other, as needed to satisfy different power conversion objectives. In this paper, the analytical models of the variable leakage and magnetizing inductances are presented. Analytical results are compared with those obtained from Finite Element Method (FEM) and an experimental prototype of a VIT. Analytical solutions of the variable leakage inductance present an error of less than 2.35 % when compared to FEM solutions, while the analytical solutions of the variable magnetizing inductance present a maximum error of 1.82 % when compared to experimental measurements.

image method, leakage inductance, magnetizing indu↗
DOE OSTI2023

Encapsulation Residual Stress and Ferrite Loss in Inductive Coil Assemblies

As inductive wireless charging reaches higher power levels, thermal management and mechanical durability become more critical. To address these concerns, past works have demonstrated the benefit of encapsulating coil assemblies in thermally conductive materials. However, due to the sensitivity of the MnZn ferrites commonly used in coil assemblies to mechanical stress, care must be taken to avoid creating large stresses in the ferrite that cause higher hysteresis loss. The stress formation in the encapsulant curing process is overviewed and modeled and an experiment is performed to demonstrate the effect in a small-scale coil assembly. Finally, the effect is shown in the reduced coil-coil efficiency of a first generation high power inductive power transfer prototype using a stiff epoxy compared to better performance in a second prototype using a softer thermally-conductive silicone encapsulant.

Foote, Andrew↗
DOE OSTI2023

Design and Optimization of High-frequency Transformer for Isolated Single-Stage Three-Phase AC/DC Converter using Bidirectional Switches

This paper presents the design and optimization of the high-frequency transformer for an isolated single-stage threephase AC/DC converter enabled by the 4H-SiC BiDirectional Field Effect Transistor (BiDFET). Non-dominated Sorting Genetic Algorithm II (NSGA-II) is used to perform a multiobjective optimization to minimize loss, weight, and volume. A 20 kW, 50 kHz hardware prototype based on the selected optimal point is characterized by a power amplifier. The finite element analysis simulation results are also presented to validate the core magnetic flux density and winding electric field strength. The experimental prototype was tested at 800 Vdc/480 Vrms at 10 kW rated power.

BiDFET, High-frequency transformer, Multiobjective↗
DOE OSTI2020

Peer-to-Peer Energy Trading and Grid Impact Studies in Smart Communities

The rise of peer-to-peer (P2P) marketplace paradigms has transformed existing marketplace models, but the extent to which this approach can be applied to the energy marketplace has yet to be considered. In this paper, we examine existing approaches taken in the application of a P2P paradigm to the energy marketplace, further presenting an approach towards facilitating an online P2P energy marketplace, implementing a prototype P2P web application named SolTrade. Furthermore, we submit initial statistics based on simulated transactions facilitated through the platform, which illustrate the physical impact of marketplace transactions on the energy grid. In particular, these results show that, as the number of users rises, the chance of overloading the grid rises, but the chance of the grid being unable to sustain itself without an external source of energy falls.

peer-to-peer economy, web development, energy shar↗
DOE OSTI2021

Composable Programming of Hybrid Workflows for Quantum Simulation

We present a composable design scheme for the development of hybrid quantum/classical algorithms and workflows for applications of quantum simulation. Our object-oriented approach is based on constructing an expressive set of common data structures and methods that enable programming of a broad variety of complex hybrid quantum simulation applications. The abstract core of our scheme is distilled from the analysis of the current quantum simulation algorithms. Subsequently, it allows a synthesis of new hybrid algorithms and workflows via the extension, specialization, and dynamic customization of the abstract core classes defined by our design. We implement our design scheme using the hardware-agnostic programming language QCOR into the QuaSiMo library. To validate our implementation, we test and show its utility on commercial quantum processors from IBM, running some prototypical quantum simulations.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2023

Efficiency and Output Power Sensitivity to Control Parameter Variations in an LCC-Series Wireless Power Transfer System

In wireless power transfer (WPT) systems, output power (Pout) can be controlled through input parameters such as, input voltage (Vin) , duty cycle (d) , and switching frequency (fsw) . The impact of these control parameters on the overall system efficiency has not been explored in previous studies. This paper focuses on the efficiency (η) and Pout sensitivity to these control parameter variations in an LCC-Series tuned WPT system. There are multiple combinations of Vin, d , and fsw that can achieve a specified target Pout . However, it is important to determine the optimal combination of these control variables that will yield the maximum η for a target Pout . A MATLAB/Simulink model is built to calculate and measure η and Pout . In order to achieve this result, several simulations are run where Vin,d , and fsw are swept across a wide range to cover all possible combinations. MATLAB's Sensitivity Analysis toolbox is used to evaluate how the parameters influence the model's output. Finally, an experimental prototype is implemented. The optimal values acquired using the sensitivity analysis is then plugged into the hardware prototype and compared with the simulation. The results obtained confirm the validity of the proposed method.

Harave, Sudarshan↗
DOE OSTI2026

Quantum Computing for AI-based Design and Optimization of Electric Motors

Knowledge-based artificial intelligence and hierarchical fuzzy logic offer an interpretable framework for electricvehicle motor preliminary design, but their computational burden grows with linguistic granularity and coupled design-space size. This paper presents a reduced quantum reformulation of the hierarchical fuzzy inference of air-gap flux density, a representative level-one motor-design parameter. Starting from the published electric-vehicle motor-design framework, a three-term fuzzy prototype is constructed from the original inference structure. The reduced model is then reformulated as a modular quantum register-oracle system, in which each hierarchical subrelation is encoded as a block oracle and evaluated through superpositionbased candidate-label testing. The proposed modular quantum formulation reproduces the reduced classical prototype after block fusion. A resource analysis shows that the reduced modular system requires seven qubits per block and twenty-two qubits in a straightforward four-block implementation. Finally, a crossovercomplexity model is derived to identify the regime in which quantum candidate search may become favorable relative to hierarchical fuzzy inference. The results show that no quantum advantage should be claimed for the present one-output reduced benchmark, but that a plausible crossover emerges for larger joint candidate spaces and higher linguistic granularity. The work therefore establishes a technically consistent starting point for future quantum-assisted electric-vehicle motor-design optimization.

Kumar, Praveen [ORNL] (ORCID:0000000291877857)↗
DOE OSTI2024

Data-Driven Digital Twin for Reliability Assessment of DC/DC Buck Converter

In commercial applications, the operation of DC/DC converters significantly impacts overall system performance and long-term reliability. This study introduces a data-driven digital twin (DT) approach for estimating critical degradation parameters of DC/DC BUCK converter under steady-state condition. Initially, a circuit-level MATLAB/Simulink digital model (DM C ) is refined against a hardware prototype’s switching model dataset using offline particle swarm optimization. The optimized digital model’s steady-state response is then verified with its average model response while varying the duty and load. Subsequently, degradation profiles are imposed on the inductor, capacitor, MOSFET in the DMC. A large dataset is generated from this model, allowing training, validation, and testing of machine learning (ML) models for component health regression tasks. The proposed method employs random forest ML models, achieving impressive regression results with a squared R value as high as 0.99978 and a root mean square error of 4.2× 10 –6 . The method is further validated on a medium power level DC/DC BUCK prototype with varying load conditions, and includes the analysis of MOSFET’s on-resistance under degradation conditions. This data-driven DT method shows promise for identifying parasitic degradation and ohmic loss parameters, enhancing converter reliability assessments in a non-invasive, generalized, and computationally efficient manner.

14 SOLAR ENERGY↗
DOE OSTI2024

IoT-Enabled Traveling Wave Microgrid Protection

Traveling Wave Protection based on the Internet of Things (TWP-IoT) is developed to enable ultra-resilient microgrids. TWP-IoT adopts a directional traveling wave approach that utilizes the voltage and current modal components obtained from Discrete Hilbert Transform to identify the fault features via ultra-lightweight IoT hardware. Furthermore, the main contributions of this work include (1) a novel TWP-IoT for microgrid and distribution networks that can achieve the time-of-arrival fault detection and localization with composite wave impedance and conductance using Discrete Hilbert Transform, (2) a cost-effective smart IoT prototype with functionalities outperforming commercial relays, and (3) a real-time hardware-in-the-loop prototype based on RTDS that verifies the robustness and efficacy of TWP-IoT subject to a diverse set of working conditions. TWP-IoT is found to have excellent performance under a wide spectrum of internal and external fault conditions across a myriad of microgrid locations, which is unattainable by today’s TWP products.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2022

Development of Fixtures and Methods to Assess the Durability of Balance of Systems Components

The degradation of photovoltaic (PV) balance of systems (BoS) components is not well studied, but the consequences include offline modules, strings, and inverters; system shutdown; arc faults; and fires. A utility provider experienced a ~30% failure rate in their power transfer chain, originally attributed to branch connectors. Field-failed specimen assemblies were, therefore, examined, consisting of cable connector, branch connector, and discrete fuse components. In this study, unused field-vintage specimens are examined using a benchtop prototype fixture to identify the most influential environmental stressors on BoS components as well as the effect of external mechanical perturbation. The prototype fixture was used to develop a perturbation capability for future use in the combined-accelerated stress testing chamber. The benchtop experiments were also used to develop the in-situ data acquisition of specimen current, voltage, and temperature. A significant increase in operating temperature (~100 °C from ~40 °C) and a different failure mode (arcing at the metal pins rather than overheating of the fuse filament) were observed promptly once periodic mechanical perturbation was applied. The current at failure was decreased from 35 A (measured for static specimens, with failure occurring in the fuses) to 15 A (for tests with mechanical perturbation, with failure at the male/female metal pin connection). After initial examination using X-ray computed tomography, the external plastic was machined away from failed specimens to allow for failure analysis, including the extraction of the internal convolute springs for morphological examination (optical and electron microscopy). Chemical composition analysis included energy-dispersive X-ray spectroscopy, differential scanning calorimetry, and Fourier transform infrared spectroscopy.

14 SOLAR ENERGY↗
DOE OSTI2023

Stochastic Look-Ahead Commitment: A Case Study in MISO

This paper introduces the Stochastic Look Ahead Commitment (SLAC) software prototyped and tested for the Midcontinent Independent System Operator (MISO) look ahead commitment process. SLAC can incorporate hundreds of wind, load, and net scheduled interchange (NSI) uncertainty scenarios. It uses a progressive hedging method to solve a novel two-stage stochastic unit commitment. The first stage commitment decisions, made only for those generators whose decision to commit or not in each time period cannot be deferred, can cover the uncertainties within the next three hours. The second stage includes both the dispatch for each of the scenarios and the commitment decisions that can be deferred. Study results on 15 MISO production days show that SLAC may bring economic and reliability benefits under uncertainty.

MATHEMATICS AND COMPUTING↗