This paper introduces a new scheme to track the
rotor slotting saliency in induction motors by using the
measurement of current derivatives in response to test vectors
imposed during null switching vectors of a standard PWM
scheme by using 3 H-bridges connected in series with a 2-Level
inverter. The scheme aims to reduce the current distortion
usually introduced by applying the sensorless control strategies
in 2-Level inverters. The H-Bridges can generate low voltage
test vectors which can be used to track the rotor slotting saliency
and the same time reduce the distortion in the current directly,
as well as shortening the minimum pulse width (t
) which adds
a further improvement to current distortion without
compromising the quality of the sensorless performance of the
system.  Moreover, the new technique can work in a wide speed
range and its implementation requires only the minimum of
control modifications to the operation of the multilevel inverter
as the proposed application of this sensorless technique is to
high power multilevel converters which use a combination of
series connected GTO and IGBT based H-Bridges to achieve a
reasonable quality medium voltage waveform for motor drives.
Also some automotive drives have recently been proposed which
use the same specific topology as used in this work. 

Conference Title

Energy Conversion Congress and Exposition (ECCE), 2010 IEEE

Conference Country

United States of America

Conference Date

Sept. 12, 2010 - Sept. 16, 2010

Conference Sponsor

IEEE

Additional Info

Conference Website