Influence of lamination thickness on harmonic losses in 2-pole slotless permanent-magnet motors

This paper presents an original theoretical and experimental investigation of the iron losses for three different commercially available non-oriented silicon-iron (SiFe) steel grades (with lamination thicknesses 0.1, 0.2 and 0.3 mm) in a 2-pole slotless permanent magnet motor. The study is conducted over a wide frequency range (10-100 kHz), which is a novelty. The corresponding winding losses are succesfully identified for this purpose. The impact of temperature is also studied. The results show that that iron losses compose a significant share of the total losses beyond 50 kHz. Stator harmonic iron losses at 100 kHz can be decreased with 30% by using NO10 instead of NO30.