Comparison of permanent magnet synchronous machines with concentrated windings and different rotor configurations

Abstract

Electric motors for traction applications are traditionally designed with internal rotors. However, torque density can be increased with the rotor in the outside. Two permanent magnet synchronous machines (PMSM) with fractional slot concentrated windings (FSCW) and internal and external rotors, designed with same electromagnetic properties and volume restrictions, are compared to prove which one gives the best performance. The external rotor machine increases the torque density by 24.9% at the expense of higher torque ripple.