EJ3221 Design of Permanent Magnet Synchronous Machines 9.0 credits

Konstruktion av permanentmagnetiserande synkronmaskiner

The aim of the course is to understand how to make an electromagnetic and thermal design of permanent magnet synchronous machines from any given set of specifications. The knowledge is applied by designing a machine for an industrial application.

  • Education cycle

    Third cycle
  • Main field of study

  • Grading scale

    P, F

Information for research students about course offerings

Given in connection with EJ2120 every year in P1-P2

Intended learning outcomes

After the course, the student should be able to:

  • list different existing topologies of permanent magnet machines
  • describe and compare distributed and concentrated windings
  • explain the principle of field-weakening for permanent magnet synchronous motors
  • choose the appropriate permanent magnet materials for a given construction with regard to functionality, operating conditions, economic and environmental factors
  • explain and compare the properties of iron laminations and soft magnetic composites in relation to their use in electrical machines
  • enumerate different loss components in a machine and relate them to different existing models
  • develop a simple analytical model of the thermal behaviour of a machine taking into account the relevant losses for the application
  • explain all the tasks in the design procedure and apply them to a surface mounted permanent magnet motor with distributed windings with simplified analytical models
  • explain discrepancies between results from different analytical methods through knowledge about the various approximations they are based on
  • describe the concepts of finite element software tools and apply them in the analysis of permanent magnet synchronous machines
  • report and present the results of the design project that has been conducted for a chosen application
  • do a critical evaluation of the report and presentation of the specific studies conducted by the other students

Course main content

Function and components of electric drive systems, application specifications, energy conversion in PM machines, torque derivation, loss, thermal constraints, modelling, permanent magnet materials, magnetic materials, topologies of PM machines (radial, axial and transverse), distributed and concentrated windings, field-weakening.


12 hours lecture, 2 hours tutorial, 82 (42+40) hours project, 15 hours project meetings


Recommended prerequisites

basic course in electrical machines and drives EJ2200


Course folder EJ2221 Design of Permanent Magnet Synchronous Machines, 2011.


  • EXA1 - Examination, 9.0, grading scale: P, F

At least 1 full-time week of project activity is preferably linked to the student’s own research.

Requirements for final grade

  • 6 status reports
  • 5 oral presentations
  • 5 opposition reports
  • Final report and oral examination

Offered by

EECS/Electric Power and Energy Systems


Oskar Wallmark


Oskar Wallmark <owa@kth.se>


Course syllabus valid from: Spring 2012.
Examination information valid from: Spring 2019.