Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “CONVERTER”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

Phase substitution of spare converter for a failed one of parallel phase staggered converters

Failure detection and substitution of a spare module is provided in a system having a plurality of phase staggered modules connected in parallel to deliver regulated voltage from an unregulated source. Phase control signals applied to the active converter modules are applied to the spare module through NOR gates associated with and disabled by the power output of respective modules such that failure of any one enables its phase control signal to be applied to the spare module, thus controlling the spare module to operate in the phase position of the failed module. A NAND gate detects when any one active module fails and enables a gate in the spare module, thus activating the spare module.

Mclyman, W. T.↗
NASA NTRS1984

A fast time domain digital simulation technique for power converters - Application to a buck converter with feedforward compensation

Small signal analysis was performed earlier to demonstrate the marked improvement of dynamic properties and stability margins of a switching regulator employing a novel feedforward input filter compensation scheme. A large signal nonlinear recurrent time domain model is presented for the converter to analyse the transient response due to a step input change with and without the presence of the proposed feedforward loop. The results are verified with experimental data.

Kelkar, S. S.↗
DOE OSTI2012

Magnet Technology for Power Converters: Nanocomposite Magnet Technology for High Frequency MW-Scale Power Converters

Solar ADEPT Project: CMU is developing a new nanoscale magnetic material that will reduce the size, weight, and cost of utility-scale PV solar power conversion systems that connect directly to the grid. Power converters are required to turn the energy that solar power systems create into useable energy for the grid. The power conversion systems made with CMU’s nanoscale magnetic material have the potential to be 150 times lighter and significantly smaller than conventional power conversion systems that produce similar amounts of power.

ARPA-E↗
DOE OSTI2022

Modeling and Feedback Compensator Design for Power-Hardware-in-the-Loop System for Medium-Voltage Grid-Connected Power Converters

Hardware-in-the-loop (HIL) evaluation is a method in which the test subject is split into a physical part and a simulated part, and these parts are connected with interfaces to form a combined physical-numerical system. Power-hardware-in-the-loop (PHIL) systems, where actual hardware is connected to a real-time model, can exhibit issues of instability, inaccuracy and errors when operating in a closed-loop. The challenges of generating a PHIL setup are that, first, because of the limited dynamic response of the different parts of the system, the test results might be inaccurate, and, second, because of the high frequency noise introduced by the sensors to the closed-loop system, it can be difficult to design a compensator for the real-time emulator response, while stabilizing the closed-loop system at the same time. In this paper, different parts of a PHIL system are characterized, and the feedback compensator system design is proposed for the stable operation of the closed-loop PHIL system. The issues as observed in a PHIL system without any compensator are demonstrated using experimental results, and the effectiveness of a first order phase lead compensator is validated.

compensator design↗
DOE OSTI2021

A Critical Review of Challenges Faced by Converting Food Waste to Bioenergy Through Anaerobic Digestion and Hydrothermal Liquefaction

Here, the conventional approaches for handling food waste has been incineration, composting, landfilling, and anaerobic digestion for producing biogas. In light of organic waste bans and newly discovered presence of per- and polyfluorinated substances (PFAS) in food, food packaging materials, and compost, this review provides a critical summary of what has been investigated and reported and what needs to be considered when choosing suitable pathways for food waste. In addition to the fundamental principles inherent to anaerobic digestion and hydrothermal liquefaction, challenges for each process are identified followed by discussion of potential solutions to resolve the bottlenecks.

09 BIOMASS FUELS↗
DOE OSTI2012

Converting environmentally hazardous materials into clean energy using a novel nanostructured photoelectrochemical fuel cell

Highlights: ► A photoelectrochemical fuel cell has been made from TiO{sub 2} nanotubes. ► The fuel cell decomposes environmentally hazardous materials to produce electricity. ► Doping the anode with a transition metal oxide increases the visible light sensitivity. ► Loading the anode with a conducting polymer enhances the visible light absorption. -- Abstract: In this work, a novel photoelectrochemical fuel cell consisting of a titanium dioxide nanotube array photosensitive anode and a platinum cathode was made for decomposing environmentally hazardous materials to produce electricity and clean fuel. Titanium dioxide nanotubes (TiO{sub 2} NTs) were prepared via electrochemical oxidation of pure Ti in an ammonium fluoride and glycerol-containing solution. Scanning electron microscopy was used to analyze the morphology of the nanotubes. The average diameter, wall thickness and length of the as-prepared TiO{sub 2} NTs were determined. The photosensitive anode made from the highly ordered TiO{sub 2} NTs has good photo-catalytic property, as proven by the decomposition tests on urea, ammonia, sodium sulfide and automobile engine coolant under ultraviolet (UV) radiation. To improve the efficiency of the fuel cell, doping the TiO{sub 2} NTs with a transition metal oxide, NiO, was performed and the photosensitivity of the doped anode was tested under visible light irradiation. It is found that the NiO-doped anode is sensitive to visible light. Also found is that polyaniline-doped photosensitive anode can harvest photon energy in the visible light spectrum range much more efficiently than the NiO-doped one. It is concluded that the nanostructured photoelectrochemical fuel cell can generate electricity and clean fuel by decomposing hazardous materials under sunlight.

36 MATERIALS SCIENCE↗