A comparative study of rotor losses in an IPM with single and double layer concentrated windings

The use of permanent magnet machines for traction applications is rapidly gaining popularity as magnets with higher energy densities are emerging. For traction applications, good field weakening characteristics are essential. In wider field weakening regions, higher frequencies drastically increases rotor eddy current losses. This is especially so for machines with higher MMF leakage harmonic content such as a machine with concentrated windings. Additional MMF leakage harmonics also present a significant increase in magnet hysteresis losses. This paper compares the effect of losses in an IPM rotor with single and double layer concentrated windings. Steady state finite element AC magnets application is used to model losses and justify studies.