Impacts of cross-saturation on sensorless control of surface permanent magnet synchronous motors

Cross-magnetisation complicates the sensorless control of non-salient AC machines, like surface magnet synchronous motors. The motor currents influence position estimation techniques for low speed based on "saturation induced" saliencies. This paper considers cross-saturation effects to explain the magnetic-axis shift under loaded conditions and discusses the influence of the operating point on the saliency. A finite element analysis and lab measurements validate the results