access icon openaccess Systematic design study into the influence of rotational speed on the torque density of surface-mounted permanent magnet machines

This is an open access article published by the IET under the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0/)
Received 26/06/2018, Accepted 30/07/2018, Published 22/01/2019

A series of systematic studies are carried out to investigate the influence on torque density and power density on machine speed rating. Several series of permanent magnet machine designs are established using an array of different electrical and thermal design constraints. The paper demonstrates that torque density in permanent magnet machines tends to decrease with speed rating due to complex interplay between electromagnetic and mechanical considerations, e.g. fixed winding current density, fixed split ratio etc. Interesting trends are observed, including cases in which there is an optimum rotational speed in terms of power density, beyond which the power density starts to decrease with increased speed rating.

Inspec keywords: torque; machine windings; permanent magnet machines

Other keywords: permanent magnet machine designs; electrical design constraints; power density; torque density; optimum rotational speed; surface-mounted permanent magnet machines; fixed split ratio; machine speed rating; thermal design constraints; fixed winding current density; systematic design study

Subjects: a.c. machines; d.c. machines

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