Design of a Switched Reluctance Machine for Extended Speed Operation

Nigel Schofield, Stephen A. Long, David Howe, Mike McClelland

Research output: Contribution to journalConference articlepeer-review

80 Citations (Scopus)


This paper presents results from a design study on the feasibility of employing high-efficiency switched reluctance (SR) machines in minimal hybrid-electric vehicles. The application requirements are presented and highlight the constraining influences of the vehicle drive-line topology on the machine design. The benefit of continuous phase current excitation is reported for the first time, demonstrating that constant power at an extended-speed operation can be realized with a higher number of phase winding turns per pole than would otherwise be achieved with conventional discontinuous current control. Thus, the torque/Ampere capability, when operating at or below base speed, is not as significantly compromised, an important consideration for the power inverter rating and, hence, drive system cost. The design procedure and simulated results are validated by measurements from a prototype machine. The results demonstrate the potential of SR technology for high-performance low-cost automotive applications, which often combine arduous environmental and volumetric constraints. In addition, the results highlight the benefits of continuous current control for extended-speed operation.

Original languageEnglish
Article number4757404
Pages (from-to)116-122
Number of pages7
JournalIEEE Transactions on Industry Applications
Issue number1
Publication statusPublished - 20 Jan 2009
Externally publishedYes
EventIEEE International Electric Machines and Drives Conference - Madison, United States
Duration: 1 Jun 20034 Jun 2003


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