Recent developments in sensorless and quasi‐sensorless drive

Abstract

There are two main types of speed/position sensorless closed‐loop variable‐speed electrical drives: sensorless and quasi‐sensorless drives. In sensorless drives, the classical speed and position sensors (transducers) are absent and are replaced by mathematical‐model‐based and/or artificial‐intelligence‐based estimators. In quasi‐sensorless drives, instead of conventional speed/position sensors, smart sensor bearings are used (e.g. SKF smart sensor bearings). The present paper discusses the latest developments in the field of sensorless and quasi‐sensorless variable‐speed high‐performance drives. Thus, a new family of sensorless and quasi‐sensorless induction motor and permanent magnet synchronous motor drives are also discussed (e.g. new sensorless vector and DTC drives, etc.). Methods which enable the operation of these drives at very low speed and also at zero stator frequency are discussed.