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Saint Paul, MN, United States

Ponick B.,Drive Power
COMPEL - The International Journal for Computation and Mathematics in Electrical and Electronic Engineering | Year: 2011

Purpose: Approaches for a miniaturisation of electrical machines that are based on an electromagnetic principle have to overcome numerous challenges. Some of these are only a result of the rules of growth (or shrinkage), some are a result of the micro technological fabrication processes. This paper aims to give an overview of the current state of the art including various examples of linear and rotating micro actuators that have been realised. Design/methodology/approach: The paper presents details of further miniaturisation by using thin film technology for depositing and structuring soft magnetic and hard magnetic material as well as copper for conductors and insulation. Findings: There are numerous limitations for the miniaturisation with respect to material properties, friction/guidance, etc. and this paper illustrates ways to overcome these limitations. Originality/value: The paper presents a compact overview on the achievements gained in 12 years of research within a collaborative research centre of the German DFG. © Emerald Group Publishing Limited. Source

Book C.F.,Georgia Institute of Technology | Walker M.L.R.,Georgia Institute of Technology | Walker M.L.R.,Drive Power
Journal of Propulsion and Power | Year: 2010

The effects of anode temperature on the performance of a 5-kW Hall-effect thruster are investigated. The performance characteristics of the P5 Hall-effect thruster are measured with and without active cooling of the anode. Thrust, ion current density, anode temperature, and cooling power are measured for discharge voltages between 100 and 500 V at xenon propellant flow rates of 4.97 and 10.0 mg/s. All experiments are performed in a 4 by 7 m stainless-steel vacuum chamber at pressures below 2.4 x 10 -5 Torr corrected for xenon. At 100 V, 4.97 mg/s, cooling affects a 6.3% increase in anode efficiency and a 56% increase in thrust-to-power (T/P). At 100 V, 10.0 mg/s, cooling affects a 2.0% increase in anode efficiency and a 7.5% increase in T/P. For both propellant flow rates, the cooled anode efficiency unexpectedly decreases as the discharge voltage increases, which leads to a maximum anode efficiency loss of 5.0 and 9.1% at 4.97 and 10.0 mg/s, respectively. Copyright © 2010 by Luca Boccaletto. Source

Sun Z.,Drive Power
IEEE Transportation Electrification Conference and Expo, ITEC Asia-Pacific 2014 - Conference Proceedings | Year: 2014

The pre-charge process is one crucial step of the operating for modular multilevel converters. Improper charging strategy may damage sub-modules due to capacitor voltage unbalance, or cause tripping operation of the whole system due to leg current overflowing. Thus, it is important to analyze the charging strategy and charging current suppressing method before designing the controller of modular multilevel converter. In this work, a novel DC-link charging strategy is proposed. Experiments results have been demonstrated to verify the validity of the proposed strategy. © 2014 IEEE. Source

Burke R.,Drive Power
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2014

The Single Pass RF Driver (SPRFD) compacts the beam from the linac without storage rings by manipulations that take advantage of the multiplicity of isotopes (16), the preserved μbunch structure, and increased total linac current. Magnetic switches on a first set of delay lines rearrange the internal structure of the various isotopic beams. A second set of delay lines sets the relative timing of the 16 isotopic beam sections so they will telescope at the pellet, in one of multiple fusion chambers, e.g. 10. Shortening each isotopic beam section uses preservation of the μbunch structure up to the final ~2 km drift before final focus. Just before the final drift, differential acceleration of the μbunches in each isotopic beam section (128 total) launches an axial collapse, referred to as the "Slick". The μbunches interpenetrate as their centers of mass move toward each other and individual μbunches lengthen due to their momentum spread. In longitudinal phase space they slide over one another as they lengthen in time and slim down in instantaneous energy spread. The permissible amount of μbunch lengthening is set by the design pulse shape at the pellet, which varies for different groups of isotopes. In narrow bands of ranges according to the role for each isotope group in the pellet, the ranges extend from 1 to 10 g/cm2 to drive the cylinder barrel and thin hemispherical end caps, to heat the ~0.5 g/cm2 ρR fast ignition zone, and to improve the quasi-sphericity of the compression of the fast ignition zones at the pellet's ends. Because the μbunch-μbunch momentum differences are correlated, time-ramped beamline transport elements close after the differential accelerator are used to correct the associated shifts of focal point. Beam neutralization is needed after the differential acceleration until adjacent bunches begin to overlap. Concurrent collapse of each isotope and telescoping of the 16 isotopes cause the current in each beamline to rise rapidly during the final microsecond of driver pulse generation. Principal topics discussed are some basic considerations for the final compression processes, benefits for pellet implosion and ignition that may result from new means to shape the power deposition in the pellet in 3D and in time, and immediate needs for investigations. Economics that use HIF's potential for large economies of scale are summarized, to establish the reality of a large fusion energy complex achieving a high share of the overall benefits of fusion: abundance, cleanliness, safety, affordability, and profits. © 2013 Elsevier B.V. Source

Drive Power | Date: 2013-05-23

A system and method are provided for monitoring driving behavior in real time, which is then used to assign points to a user, such as the driver, a passenger, friends of the driver or passenger, and the like. The assignment of points can be effective at influencing current and future driving behavior of users via gamification and social networking. Users of the described system and method can engage with each other in a fun, competitive, and social way, using leaderboards, contests, points and rewards, and other gamification concepts. The system and method may be loaded onto a smartphone and may be auto-controlled based on one or more predetermined trigger events, which may be internally or externally controlled. An occurrence of the trigger event may cause the system to auto-start or to auto-end without the user interacting with the smartphone.

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