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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 1,171 records · Page 65
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Medium voltage planar DC bus distributed capacitor array

An inverter with a modular bus assembly is described. In various embodiments, the modular bus assembly includes a laminated motherboard and a plurality of capacitor daughtercards. The laminated motherboard can be configured to interface a plurality of phase-leg modules and a plurality of capacitor daughtercards through a plurality of terminals and connectors located on a bottom side or a top side of the laminated motherboard. The laminated motherboard includes a layer stack with a plurality of conductor layers. Each of the plurality of conductor layers is implemented with a net spacing from a neighboring plated through hole (PTH) based at least in part on differences in potential to be applied to each of the plurality of conductor layers as compared to a potential to be applied to the PTH. Embedded shield polygons can be implemented on the laminated motherboard to mitigate surface discharge at surface terminal (PTH/SMT) triple junctions.

Ravi, Lakshmi↗
DOE OSTI2021

Machine Learning for Improved Availability of the SNS Klystron High Voltage Converter Modulators

Beam availability has increased at the SNS, however, the targeted availability is greater than 95 %, while the SNS has failed to meet lower targets in the past. The HVCM used to power the linac klystrons have been one source of lost beam time and was chosen to explore using AI/ML techniques to improve reliability. Among the possibilities being explored are automating the tuning of HVCMs and predicting component failures such as capacitor aging, rectifier assemblies containing hundreds of diodes, and insulating oil degradation. The methodology pursued includes data cleaning, de-noising, post-analysis data labeling, and machine learning model development. We explore using Long Short-Term Memory and autoencoders for anomaly detection and prognostication used to schedule maintenance. We evaluate the use of model regularizers and constraints to improve the performance of the model and investigate methods to estimate the uncertainty of the models to provide a robust prediction with statistical interoperability. This paper describes the operational experience and known failures of the HVCMs and the proposed ML methodology and the preliminary results of training the AI/ML algorithms.

Pappas, Chris↗
DOE OSTI2023

Partial discharge suppression in high voltage solid-state devices

Devices, methods and techniques are disclosed to suppress electrical discharge and breakdown in insulating or encapsulation material(s) applied to solid-state devices. In one example aspect, a multi-layer encapsulation film includes a first layer of a first dielectric material and a second layer of a second dielectric material. An interface between the first layer and the second layer is configured to include molecular bonds to prevent charge carriers from crossing between the first layer and the second layer. The multi-layer encapsulation configuration is structured to allow an electrical contact and a substrate of the solid-state device to be at least partially surrounded by the multi-layer encapsulation configuration.

Sampayan, Stephen↗
DOE OSTI2023

Startup process for a dual active bridge converter to prevent over-voltage failure and thermal run-away

A system and method for controlling a dual active bridge based DC/DC converter. A controller implements a startup control scheme and DC bus pre-charge routine to prevent damage to the converter upon startup. During startup of the converter, the startup control process can be used to prevent excessive phase-shift and the DC bus pre-charge routine adjusts the pulse width modulated duty cycle by increasing the dead time between signals, resulting in a decreased DC bus capacitor.

Singh, Braj K.↗
DOE OSTI2023

Can We Lower the Voltage of a Silicon Module and Still Make It Just as Efficient

For thousands of years, scientists have studied the universe for many different reasons, but one reason, in particular, comes down even to the smallest materials in the universe. The universe is made of thousands of different particles. These cosmic particles are hugely important to figuring out how the universe works. But to figure out how these cosmic particles work and their purposes, there has to be something that can collect data and information on them.

Mason, Eddie↗