T. Wolbank:
"Application of AC Machines Transient Electrical Behavior for Motoring and Control of Inverter-Fed Drives";
Technische Universität Wien / Fakultät für Elektrotechnik und Informationstechnik, 2004.

Currently Though the calculation power of today's signal
processors are more than sufficient for very sophisticated high dynamic
control algorithms almost all ac machine control methods are based only on
the fundamental wave of the machine neglecting the high frequency and
transient properties. This applies not only to standard machine and drive
control but also to the fields of on-line monitoring and control with
reduced number of sensors.
The research of the author in the past years has been focused on the
exploitation of this behavior as well as on the introduction of the
additional information gained into drive control.
In the first part of this contribution the state of international research
in the field of zero-speed sensorless control of induction machines is
reviewed by outlining the methods proposed in literature all based on the
detection of saliencies not visible in fundamental wave models of the
machine. This is followed by a description of the achievements of the
author on this topic. These include the influence of machine design
parameters on the inherent saliencies, the separation of one new saliency
unknown till then, as well as improvements of the excitation, the sensing,
the signal processing of a sensorless control method, as well as the
resulting control of induction machines.
The following chapters deal with the application of the author's
fundamental results on the transient electrical behavior of induction
machines to other fields of research like condition monitoring and current
control based only on dc link sensors.
After a review of the state of international research in the field of
condition monitoring the achievements of the author on this topic are
described. These include the invention of different methods to detect fault
conditions even under inverter fed operation by surmounting the problems
associated with the commonly applied Fourier transform in combination with
transient operation and inverter harmonics. It is shown that working in the
frequency domain can be avoided by exploiting the transient electrical
current response.
The last section deals with the field of current control based only on dc
link measurements. After a review of the international state of research
and a description of the main problems and limitations in this field, the
achievements of the author in this area are presented. These are again
based on the fundamental results of the transient electrical behavior
obtained in the field of zero speed control of induction machines and allow
an accurate estimation of the current space phasor even in critical
operating ranges.