MELO FILHO, J. B.; http://lattes.cnpq.br/9842958500943000; MELO FILHO, José Bione de.
Resumo:
The appearance of the field oriented control strategies (indirect-IFOC or direct-DFOC)
has increased the interest for electric driving using assynchronous machines. In this work,
the indirect field orientation control - IFOC is studied, i n which i t is very useful for systems
operating w i t h high performance. This method is based on decoupled control of rotor flux
and electromagnetic torque, for which i t is necessary to know the rotor flux vector frequency.
This frequency is thus determined by adding the machine speed and the slipping frequency.
IFOC is essentially a feedforward scheme and presents as desadvantages the use of a speed
sensor and the dependency of machine parameters. Nowadays, several works have proposed
a better performance for this strategy, using adaptatives models for compensating the
parametric variations. I n this study, the reference model adaptative techniques are adopted
for estimating directly the machine speed, only using stator variables. The proposed scheme
permits that IFOC may be implemented without speed sensor and the IFOC may be tuned,
despite of the rotor time constant changes. I n this work, the influence of rotor time constant
in IFOC control is analysed and an extensive bibliography review concerning compensation
techniques of rotor time constant and sensorless speed strategies is presented. It is also
addressed different reference models types to be used in the adaptation scheme. The
simulation and experimental results are also presented.