M. Nikowitz, M. Hofer, M. Schrödl:
"Improvements on a Sensorless Controlled Synchronous Reluctance Machine Down to Standstill";
Talk: International Conference on Power Conversion and Intelligent Motion (PCIM), Nürnberg, Germany; 06-05-2018 - 06-07-2018; in: "IEEE", Vde Verlag Gmbh, (2018), ISBN: 978-3-8007-4646-0; 150 - 155.

A position - sensorless controlled synchronous reluctance
machine (SynRM) is discussed in this paper.
Induction motors (IMs), widely used in industry,
achieve a lower efficiency than SynRMs [1][2][3],
which leads to higher operating costs. To reduce
these costs it is reasonable to replace IMs by Syn-
RMs. An additional option to increase the economic
benefit is to replace the angular position sensor by
implementing sensorless methods. This work shows
that improvements on the sensorless behaviour are
reached by using a high PWM frequency to reduce
the ripple current in the dc-link. This approach reduces
the losses in the capacitors and provides a
silent operation of the sensorless method at a higher
position estimation bandwidth. In order to realise
sensorless control at such an increased PWM frequency
it is necessary to reduce current sensing
noise as well as to improve the observer behaviour
by implementation of a non-linear observer of the
mechanical system. Experimental results with the
prototype are presented and characterise the performance
of the improved sensorless method.