A Review of Modern Controlling Technologies in Doubly Fed Induction Generators(DFIG)

Doubly fed induction generators (DFIG) based wind turbine is an emerging technology, which is applicable for fixed speed generator system. The DFIG system consists of a Wound Rotor Induction Generator (WRIG) with the stator windings directly connected to the constant frequency three-phase grid and with the rotor windings connected to grid through a bidirectional back-to-back IGBT based voltage source converter. This system allows a variable speed operation over a large range. This paper provides a comprehensive review the basic features and normal operation of DFIG systems for wind power applications and different aspects including their variable-speed feature, control systems, and application issues.