A new sensorless commutation technique for brushless DC motors

Gambetta, D. and Ahfock, A. (2009) A new sensorless commutation technique for brushless DC motors. IET Electric Power Applications, 3 (1). pp. 40-49. ISSN 1751-8660

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In brushless DC (BLDC) drives commutation is performed by power electronic devices forming part of an inverter bridge. Switching of the power electronic devices has to be synchronised with rotor position. Determination of position, with or without sensors is an essential requirement. The most common sensorless method is based on detection of the zero crossings of back EMF signals. This technique works only above a certain speed. BLDC systems which rely solely on back EMF signals for commutation suffer from relatively poor starting performance characterised by back rotation of up to one hundred and eighty electrical degrees and fluctuations in electromagnetic torque. The aim of this project has been to investigate the possibility of a sensorless technique which is cost effective but with a performance at start-up comparable with that obtained when Hall sensors are used. Initial investigations led to a saliency based method. Theoretical analysis is presented which shows that the method is insensitive to variations in operational parameters such as load current and speed or circuit parameters such as power device voltage drops and winding resistances. Also a starting strategy, relying on saliency related measurements, is proposed which offers starting performance as good as Hall sensor based techniques.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: This paper is a postprint of a paper submitted to and accepted for publication in IET Electric Power Applications and is subject to Institution of Engineering and Technology Copyright. The copy of record is available at IET Digital Library.
Faculty / Department / School: Historic - Faculty of Engineering and Surveying - Department of Electrical, Electronic and Computer Engineering
Date Deposited: 28 Mar 2010 10:37
Last Modified: 25 Jun 2014 05:57
Uncontrolled Keywords: brushless DC motors; sensorless commutation control
Fields of Research : 09 Engineering > 0906 Electrical and Electronic Engineering > 090603 Industrial Electronics
09 Engineering > 0906 Electrical and Electronic Engineering > 090601 Circuits and Systems
09 Engineering > 0906 Electrical and Electronic Engineering > 090699 Electrical and Electronic Engineering not elsewhere classified
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970109 Expanding Knowledge in Engineering
Identification Number or DOI: 10.1049/iet-epa:20070517
URI: http://eprints.usq.edu.au/id/eprint/6490

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