withω ω ω R S = − mech , the rotor slip frequency.
The synchronous reference frame can be linked to the
stator or rotor flux of the machine. However, a reference
frame linked to the stator voltage space vector v S is a convenient
alternative because the DFIG operates as a generator
maintaining or being fed with constant stator voltage [4].
Hence, stator voltage and stator current are either given (line
operation) or controlled (island operation) variables.
Two interpretations of the DFIG dynamic equations are
possible, depending on the state variables selected in the