David James Powell
University of Sheffield
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Publication
Featured researches published by David James Powell.
ieee industry applications society annual meeting | 2005
Melanie Michon; Stuart D. Calverley; David James Powell; R.E. Clark; D. Howe
This paper describes a flexible modelling technique for the dynamic simulation of a switched reluctance machine employed in an automotive turbo-electric application to recuperate electrical energy. Due to the increasing numbers of electrically driven ancillaries and associated electrical load on the vehicle, a model which can be readily employed in a hierarchical system simulation of the vehicle electrical architecture, realised within the SABER environment, is required. The model allows comprehensive modelling of an extensive range of control strategies to be performed and appropriate switching control angles to be identified. Trade-off studies are performed in order to minimise global system losses while ensuring RMS and peak currents, and hence component ratings, are not excessive. The simulation is complemented using accurate iron loss calculations performed on a range of control conditions. A case study of a 70,000 rpm, 2.3 kW switched reluctance machine is presented.
3rd International Energy Conversion Engineering Conference | 2005
David James Powell; G.W. Jewell; Jason D. Ede; D. Howe; S. Yorks
*† ‡ § . This paper considers the feasibility of incorporating a switched reluctance starter generator within the high -pressure (HP) region of a large civil aero -engine, specifically in terms of achievable power densities, inverter rating, machine losses and the consequent cooling requirements. The high -pressure shaft of a typical large turbo -fan e ngine rotates at speeds of ~15000rpm on a typical flight duty cycle, and up to ~20000rpm in an over -speed condition, with ambient temperatures of the order of 300 to 400°C and the required powe r rating is in excess of 100kW. This harsh operating environmen t necessitates a multi -physics design approach, encompassing mechanical, thermal, electromagnetic and electrical disciplines, and serves to quantify the performance trade -offs that result from closely integrating an electrical machine into the harsh enviro nment of an aircraft engine. Nomenclature PFE = Iron loss density (W/kg) � = Electrical conductivity ( � -1 ) � = Mass density (kg/m 3 ) � = Period of flux waveform (s) d = Lamination thickness (m) B = Instantaneous flux density (T) ke = Excess loss coefficient kh,a,b = Hysteresis loss coefficients
international electric machines and drives conference | 2007
David James Powell; Kais Atallah; G.W. Jewell
The paper describes a method of modeling heat flow in flooded rotor electrical machines for electro-hydrostatic actuators. In particular, a novel technique for lumped parameter representation of the transient thermal behavior of hydraulic fluid in the airgap is presented. The technique has been applied to a flooded rotor brushless permanent magnet motor for an aerospace application, and it is shown that there is good agreement between measurements and predictions.
IEE Proceedings - Electric Power Applications | 2003
David James Powell; G.W. Jewell; D. Howe; Kais Atallah
Archive | 2009
Stuart D. Calverley; David James Powell
Archive | 2010
Stuart D. Calverley; David James Powell
Archive | 2010
David James Powell; Stuart D. Calverley
ieee international magnetics conference | 2005
David James Powell; G.W. Jewell; Stuart D. Calverley; D. Howe
Archive | 2011
David James Powell; Stuart D. Calverley
Archive | 2008
David Reginald Trainer; John James Anthony Cullen; Christopher Mark Johnson; David James Powell; Stuart D. Calverley