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Dive into the research topics where David James Powell is active.

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Featured researches published by David James Powell.


ieee industry applications society annual meeting | 2005

Dynamic model of a switched reluctance machine for use in a SABER based vehicular system simulation

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

An integrated starter -generator for a large civil aero -engine

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

Thermal Modeling of Flooded Rotor Electrical Machines for Electro-Hydrostatic Actuators

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

Rotor topologies for a switched-reluctance machine for the 'more-electric' aircraft engine

David James Powell; G.W. Jewell; D. Howe; Kais Atallah


Archive | 2009

MAGNETIC POLE-PIECE SUPPORT

Stuart D. Calverley; David James Powell


Archive | 2010

Electric marine propulsion device with integral magnetic gearing

Stuart D. Calverley; David James Powell


Archive | 2010

MAGNETICALLY GEARED MACHINE FOR MARINE GENERATION

David James Powell; Stuart D. Calverley


ieee international magnetics conference | 2005

Iron loss in a modular rotor switched reluctance machine for the 'more-electric' aero-engine

David James Powell; G.W. Jewell; Stuart D. Calverley; D. Howe


Archive | 2011

LARGE MAGNETICALLY GEARED MACHINES

David James Powell; Stuart D. Calverley


Archive | 2008

Switch arrangements for series or parallel connection of windings in a starter-generator

David Reginald Trainer; John James Anthony Cullen; Christopher Mark Johnson; David James Powell; Stuart D. Calverley

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D. Howe

University of Sheffield

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G.W. Jewell

University of Sheffield

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Kais Atallah

University of Sheffield

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Jason D. Ede

University of Sheffield

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R.E. Clark

University of Sheffield

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