Loss Evaluation in a Ductile Cast Iron Frame of a Permanent Magnet Synchronous Motor

In this study, the loss of a permanent magnet synchronous motor (PMSM) with a ductile iron frame is evaluated. First, the magnetic and electrical properties of the ductile iron FCD400 that was used for the frame were measured. Subsequently, the measured properties were applied to the loss analysis of the PMSM with the ductile iron frame. The results of the analysis demonstrate that significantly large losses are generated in the frame when the stator core is highly saturated. In addition, the effect of carrier harmonics on the generated frame loss was examined. As a result, the frame loss is mainly generated by the fundamental component included in the pulse-width modulation voltage waveform, and the contribution of the carrier harmonics is negligibly small. Finally, the effect of the presence of the frame on the torque performance at low-speed and high-torque conditions is discussed.