Abstract:
This research presents the theory, design and simulation of a fuzzy
logic based controller used for an indirect field oriented controlled three
phase induction motor (IM). Field Oriented Control (FOC) theory is the base
of special control method for induction motor drives. With this theory
induction motors can be controlled like a separately excited dc motor. This
method enables the control of field and torque of induction machine
independently by manipulating the corresponding oriented quantities.
Induction motor is modeled in stationary reference frame in term of dq
form. Three speed control techniques, Direct, Scalar and conventional PD
are used to compare the performance of the control system with fuzzy logic
controller. The models are carried out using MATLAB/SIMULINK. The
simulation results demonstrate that the performance of the Indirect Field
Oriented Control (IFOC) technique with fuzzy logic controller is better,
especially with dynamic disturbances than that for the other three types of
control. Besides that the research focuses on studying the effect of some
fuzzy controller parameters on indirect field oriented control of an induction
motor. Those parameters include the shape and number of linguistic
variables of membership functions (MFs). Only Triangular, Gaussian and
Bell membership functions are considered for the shape. The fuzzy
controller uses both the speed error and its rate of change as input, and
electromagnetic torque as an output in a relationship mapped by a fuzzy
rules table.
