Permanent magnet synchronous drives observability analysis for   motion-sensorless control
  Motion-sensorless control techniques of electrical drives are attracting more attention in different industries. The local observability of sensorless permanent magnet synchronous drives is studied in this paper. A special interest is given to the standstill operation condition, where sensorless drives suffer of poor performance. Both, salient and non-salient machines are considered. The results are illustrated using numerical simulations. 
Mohamad Koteich, Abdelmalek Maloum, Gilles Duc, Guillaume Sandou
math.CA