Sensorless control ofPM synchronous motorsandbrushless DC motors. An overview andevaluation.

This paperprovides areview oftheliterature addressing sensorless operation methods ofPM brushless machines. Themethods explained arestate-of-the-art ofopenandclosed loop control strategies. Theclosed loop review includes those methods based onvoltage andcurrent measurements, those methods based onbackemfmeasurements, andthose methods based onnovel techniques not included intheprevious categories. Thepaperconcludes with acomparison table including all main features forallcontrol strategies.