Optimized INFORM measurement sequence for sensorless PM synchronous motor drives with respect to minimum current distortion

In this paper, a standard measurement sequence for INFORM-based sensorless position estimation of permanent-magnet synchronous motors is analyzed. Its properties with respect to the current deviation caused by the INFORM measurement are pointed out. Based on that a modified measurement sequence with minimum current deviation and minimum time demand is introduced. Measurement results verify the improvement of the modified measurement sequence: The current distortion is reduced significantly, resulting in reduced additional losses. Additionally, several measurement results concerning the performance of the sensorless position estimation under various load conditions are presented. Successful industrial applications are given.