This book describes the development of an adaptive state observer using
a mathematical model to achieve high performance for sensorless
induction motor drives. This involves first deriving an expression for a
modified gain rotor flux observer with a parameter adaptive scheme to
estimate the motor speed accurately and improve the stability and
performance of sensorless vector-controlled induction motor drives. This
scheme is then applied to the controls of a photovoltaic-motor
water-pumping system, which results in improved dynamic performance
under different operating conditions. The book also presents a robust
speed controller design for a sensorless vector-controlled induction
motor drive system based on H∞ theory, which overcomes the problems of
the classical controller.