Electrical/Electronics

Fault Recovery for Multi-Phase Power Converters

This method has application in power converters for thin film deposition to prevent loss of expensive silicon wafer products. John H. Glenn Research Center, Cleveland, Ohio A fault recovery method for multiphase power converters enables delivery of reduced output power of as much as 66% of normal power in the event of a shorted power switch component. The need for redundant power converters in conventional multi-phase space power systems is reduced, if not eliminated. Fault recovery includes detecting a shorted power switch fault, providing short circuit current protection, providing isolation of the shorted power switch, and reconfiguring the remaining undamaged power switches.

Posted in: Briefs, TSP, Electronics & Computers, Power Management

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Isolated Bidirectional DC Converters for Distributed Battery Energy Applications

This development is applicable to electric propulsion systems of vehicles. John H. Glenn Research Center, Cleveland, Ohio Power systems are the core heartbeat of any advanced vehicle. Reliability and flexibility of these systems are of the highest priority. This innovation is a highly efficient and modular isolated bidirectional DC converter for battery energy applications that has been translated into high-priority NASA power system applications, demonstrating transferability, robustness, and scalability.

Posted in: Briefs, TSP, Electronics & Computers, Power Management

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Device Accommodating Volume Expansion and Contraction for Water-Ice Phase Change Material Heat Sinks

This innovation enables the use of water as a phase change material for thermal energy storage. Lyndon B. Johnson Space Center, Houston, Texas This invention accommodates the volume expansion and contraction of water ice as it freezes and thaws, thus enabling the use of water as a phase change material (PCM) for thermal energy storage. Due to the relatively large volume expansion of water upon freezing, and the relatively large bulk modulus of elasticity of ice, it is imperative to accommodate the volume expansion in order to prevent rupture of the containment vessel. In addition to accommodating the volume expansion associated with the phase change from liquid water to solid ice, this invention is usable at temperatures as low as –150 °C, thus enabling the ice to be super-cooled for additional sensible thermal storage capacity. Finally, this invention operates independent of gravity, enabling its use in space applications.

Posted in: Briefs, TSP, Electronics & Computers, Power Management

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High-Power, Solid-State Power Amplifier System

Marshall Space Flight Center, Alabama The purpose of the invention was to increase the operational power levels of solid-state power amplifiers using state-ofthe- art power amplifier design and combining methodology. Using 1-kW RF modules and proper RF combining techniques, a system was built that generated 16 kW of RF power for use in electric plasma propulsion. The 1-kW units were fault-protected against excessive power, excessive current, and high VSWR, since the RF power devices are extremely sensitive to variations in their operating conditions.

Posted in: Briefs, Electronics & Computers, Power Management

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H2O/NaCl-Based Radio Frequency Power Load

Marshall Space Flight Center, Alabama The purpose of the invention was to increase the operational power levels of power loads as well as improve the overall reliability and safety of existing systems. Using water (H2O), table salt (NaCl) or some other form of salt, and a matching network, an RF power load can be built to absorb transmitted power levels in the 10s or 100s of kilowatts, where the water absorbs the power. The only byproduct is the barely detectable heating of the water bath.

Posted in: Briefs, Electronics & Computers, Power Management

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Discovery Through Eigenbasis Modeling of Uninteresting Data

The system learns only what to ignore, reducing the possibility of missing the items of interest. NASA’s Jet Propulsion Laboratory, Pasadena, California When presented with a new data set, a common initial goal is to explore its contents in a discovery mode to find items of interest. However, each user who views the data set may have a different scientific goal in mind, and therefore a different desired prioritization of the items for examination. Further, as the users explore more of the data set, they accumulate concrete examples of what is or is not of interest. The goal of this work was to formalize this iterative approach to understanding large data sets, and instantiate it with methods capable of the necessary adaptation as the system iteratively acquires user feedback.

Posted in: Briefs, TSP, Electronics & Computers, Information Sciences, Software

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Obstacle Avoidance Methods

NASA’s Jet Propulsion Laboratory, Pasadena, California Obstacle avoidance is a difficult problem due to the non-convex state constraints. Therefore, the feasible state space needs to be convexified, or split, into convex regions at which point the search for an optimal solution among those convex regions is done. Methods for obstacle avoidance include two mixed integer linear programming (MILP) methods (obstacle related method and path-related method) and a state-constraint convexification method.

Posted in: Briefs, TSP, Electronics & Computers, Information Sciences, Software

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