Discussion of "Regenerating-mode low-speed operation of sensorless induction motor drive with adaptive observer" [and closure]

M. Depenbrock and A. Steimel comment on the paper by H. Kubota et al. (see ibid., vol.38, p.1081-6, 2002), pointing out that some of the problems to be solved have already had solutions published, one of which is protected by a German Patent. H. Kubota replies to the comments.