1,690 research outputs found
Analysis of Implementation Methodologies of Deadbeat Direct-Torque and Flux Control (DB-DTFC) for IPMSMs in Stationary and Rotatory Reference Frames
Deadbeat-control is a well-established control technique that uses the inverse machine model to determine the voltage commands required to achieve the desired torque and flux commands. Its classic implementation requires solving a quadratic equation with an extensive number of terms. Moreover, it can be only solved in the dq-reference frame. In this paper, two novel implementations are presented. The first methodology, in the dq-reference frame, reduces the algorithm's complexity and computation time. Moreover, it is immune to estimation errors of the permanent magnet flux. A second methodology based on the flux vector orientation is also presented. As opposed to the classic implementation, the proposed method does not require solving a quadratic equation; this reduces its complexity and computation time. Furthermore, the proposed methodology can be solved both in the dq and aß frames since it relies only on the stator flux's magnitude and angle. Up to date and to the best of the author's knowledge, DB-DTFC in the stationary frame has not been presented before for salient machines. DB-DTFC in the stationary frame reduces the reliance on the position observer and facilitates the implementation of overmodulation techniques and six-step operation. The proposed methodology can operate in the MTPF line without any adjustments and it shows an adequate dynamic performance. Simulation and experimental results validate the methodologies. Caveats regarding their implementation are also discussed
Wind Electrolysis: Hydrogen Cost Optimization
This report describes a hydrogen production cost analysis of a collection of optimized central wind based water electrolysis production facilities. The basic modeled wind electrolysis facility includes a number of low temperature electrolyzers and a co-located wind farm encompassing a number of 3MW wind turbines that provide electricity for the electrolyzer units
Modeling magnetospheric fields in the Jupiter system
The various processes which generate magnetic fields within the Jupiter
system are exemplary for a large class of similar processes occurring at other
planets in the solar system, but also around extrasolar planets. Jupiter's
large internal dynamo magnetic field generates a gigantic magnetosphere, which
is strongly rotational driven and possesses large plasma sources located deeply
within the magnetosphere. The combination of the latter two effects is the
primary reason for Jupiter's main auroral ovals. Jupiter's moon Ganymede is the
only known moon with an intrinsic dynamo magnetic field, which generates a
mini-magnetosphere located within Jupiter's larger magnetosphere including two
auroral ovals. Ganymede's magnetosphere is qualitatively different compared to
the one from Jupiter. It possesses no bow shock but develops Alfv\'en wings
similar to most of the extrasolar planets which orbit their host stars within
0.1 AU. New numerical models of Jupiter's and Ganymede's magnetospheres
presented here provide quantitative insight into the processes that maintain
these magnetospheres. Jupiter's magnetospheric field is approximately
time-periodic at the locations of Jupiter's moons and induces secondary
magnetic fields in electrically conductive layers such as subsurface oceans. In
the case of Ganymede, these secondary magnetic fields influence the oscillation
of the location of its auroral ovals. Based on dedicated Hubble Space Telescope
observations, an analysis of the amplitudes of the auroral oscillations
provides evidence that Ganymede harbors a subsurface ocean. Callisto in
contrast does not possess a mini-magnetosphere, but still shows a perturbed
magnetic field environment. Callisto's ionosphere and atmospheric UV emission
is different compared to the other Galilean satellites as it is primarily been
generated by solar photons compared to magnetospheric electrons.Comment: Chapter for Book: Planetary Magnetis
ARRA Material Handling Equipment Composite Data Products: Data Through Quarter 4 of 2012
This presentation from the U.S. Department of Energy's National Renewable Energy Laboratory includes American Recovery and Reinvestment Act (ARRA) fuel cell material handling equipment composite data products for data through the fourth quarter of 2012
Interaction of Saturn's magnetosphere and its moons: 1. Interaction between corotating plasma and standard obstacles
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95046/1/jgra20170.pd
ARRA Material Handling Equipment Composite Data Products: Data through Quarter 2 of 2012
This presentation from the U.S. Department of Energy's National Renewable Energy Laboratory includes American Recovery and Reinvestment Act (ARRA) fuel cell material handling equipment composite data products for data through the second quarter of 2012
The roles of charge exchange and dissociation in spreading Saturn's neutral clouds
Neutrals sourced directly from Enceladus's plumes are initially confined to a
dense neutral torus in Enceladus's orbit around Saturn. This neutral torus is
redistributed by charge exchange, impact/photodissociation, and neutral-neutral
collisions to produce Saturn's neutral clouds. Here we consider the former
processes in greater detail than in previous studies. In the case of
dissociation, models have assumed that OH is produced with a single speed of 1
km/s, whereas laboratory measurements suggest a range of speeds between 1 and
1.6 km/s. We show that the high-speed case increases dissociation's range of
influence from 9 to 15 Rs. For charge exchange, we present a new modeling
approach, where the ions are followed within a neutral background, whereas
neutral cloud models are conventionally constructed from the neutrals' point of
view. This approach allows us to comment on the significance of the ions'
gyrophase at the moment charge exchange occurs. Accounting for gyrophase: (1)
has no consequence on the H2O cloud; (2) doubles the local density of OH at the
orbit of Enceladus; and (3) decreases the oxygen densities at Enceladus's orbit
by less than 10%. Finally, we consider velocity-dependent, as well as
species-dependent cross sections and find that the oxygen cloud produced from
charge exchange is spread out more than H2O, whereas the OH cloud is the most
confined.Comment: Accepted to the Journal of Geophysical Research, 49 pages, 10 figure
Recommended from our members
Next Steps for the FCEV Learning Demonstration Project
This presentation summarizes project goals; vehicle and H2 station deployment status, critical performance compared to targets; highlights of latest vehicle and infrastructure analysis results and progress; learning demo next steps; highlights of partner activities and summary
Recommended from our members
Final Results from U.S. FCEV Learning Demonstration: Preprint
The 'Controlled Hydrogen Fleet and Infrastructure Demonstration and Validation Project,' also known as the National Fuel Cell Electric Vehicle Learning Demonstration, is a U.S. Department of Energy (DOE) project started in 2004 and concluded in late 2011. The purpose of this project was to conduct an integrated field validation that simultaneously examined the performance of fuel cell vehicles and the supporting hydrogen fueling infrastructure. The DOE's National Renewable Energy Laboratory (NREL) received and analyzed all of the raw technical data collected by the industry partners through their participation in the project over its seven-year duration. This paper reviews highlights from the project and draws conclusions about the demonstrated status of the fuel cell vehicle and hydrogen fueling infrastructure technology
- …