Review of sensorless control methods in switched reluctance motor drives

This paper covers an entire range of topics related to sensorless control of switched reluctance motor (SRM) drives including their fundamentals, limitations and current state of research and future trends. This should help the reader to develop a systematic understanding of the sensorless techniques that have been presented in the literature. The conventional methods used for position sensing in SRM drives have the disadvantages of additional cost, additional electrical connections, mechanical alignment problem, less suitability to space restricted applications and the significant disadvantage of being an inherent source of unreliability. This motivated the development of several sensorless techniques, some of which are successfully implemented and are commercially available. Ideally, it is desirable to have a sensorless scheme, which uses only terminal measurements and does not require additional hardware: while maintaining a reliable operation over the entire speed and torque range with high resolution and accuracy. Finally, this paper includes an example of laboratory implementation of sensorless control technique. It is found that reliable sensorless SRM drives are now practical, thus making SRMs, the drives of many future applications.