Investigating Synchronous Reluctance Rotor Performance for Traction Applications against a Permanent Magnet Benchmark

This paper investigates the potential benefits for the use of synchronous reluctance machines for traction applications. Permanent magnet machines are often used to generate the highest power densities. However, magnet use has drawbacks including temperature limits requiring localised, intensive, and often complex and expensive cooling strategies. In addition, ethical, environmental, geopolitical, and economic concerns impact short term market fluctuations and long-term demand. In this paper a benchmark PM machine has been taken, and an alternative synchronous reluctance rotor has been designed. The purpose was to identify how much performance could be maintained through improved multi-physics analysis and the design freedom that magnet removal enabled. Performance and cost comparisons are presented. The synchronous reluctance design has 65% of the active material cost of the PM machine yet maintains 94% of the torque density. The result of these changes is a 31% saving in terms of cost per unit torque density.