Sub-assembly experiments to determine PWM supply-induced losses in electric machines

Jonathan Godbehere, Andrew Hopkins, David Drury, Phil Mellor

Research output: Chapter in Book/Report/Conference proceedingConference Contribution (Conference Proceeding)

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This paper presents a low cost approach to experimentally characterise the effect of the inverter supply on the losses in an electrical machine. The set-up comprises of representative subassemblies of the stator and winding, referred to as ‘motorettes’, and a single phase, fast switching silicon-carbide based converter. The sub-assembly based thermal analysis has been shown to be a time and cost-effective method to examine winding loss, over a range of operating conditions. In addition to the slot to stator thermal resistance and capacitance. This provides critical information for thermal model calibration, and produces more accurate thermal and loss predictions of the full machine behaviour. A test arrangement has been devised to replicate the magnetic excitation of the electrical machine stator during normal operation. This builds upon previous techniques, to allow iron loss to be investigated. Through multiple tests using DC, AC and PWM-AC supplies, a 20% increase in iron loss is observed due to PWM effects.
Original languageEnglish
Title of host publication9th IET International Conference on Power Electronics, Machines and Drives (PEMD 2018)
PublisherInstitution of Engineering and Technology (IET)
Number of pages5
Publication statusPublished - Jun 2019

Publication series

NameJournal of Engineering
ISSN (Electronic)2051-3305


  • lumped parameter thermal model
  • motorette assembly
  • iron loss
  • thermal design


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