Abstract:
The development technologies relating to the wind energy conversion into electrical energy
in order to satisfy the growing demands on the existing electrical networks represents a very
important issue among other the other renewable energy existing resources. This trend is justified
by its ability to be implemented on large scales with respect to environmental requirements.
The doubly-fed induction machine (DFIM) equipped with two static converters and driven by
a wind turbine is the simplest and most efficient ways for converting the stored energy in the wind
into electrical energy sent directly to the distribution network in the form of active and reactive
powers. By the use of different field oriented control strategies, each of these two kinds of power
could be controlled separately.
The design of control laws that governing the operation of the DFIM based wind energy
system conversion is conventionally based on the vector control technique application which
consists in controlling the electromagnetic torque and the flux of this machine in a similar way of
that of the separated DC machines under the assumption that network to which the stator of the
DFIM is connected must be perfectly balanced. Nevertheless, as a real network voltage is usually
affected by a given asymmetry, the above assumption can never be realized. The aim of this work is
to find a way to make the classical vector control still applicable in the case of an unbalanced utility.
