Doubly Fed Induction Generator Based Wind Energy Conversion System: A Review

Doubly-Fed Induction Generator (DFIG) based wind turbine has gained attention in present day wind power industry due to its performance. D F I G uses the concept of variable speed, variable pitch and torque to control the variation of wind speed relative to the output. In wind energy conversion system, the stator terminal is connected to the grid while the rotor is connected via a bidirectional converter in which DFIG is employed.  However, DFIGs are highly subjected to some system disturbances like grid voltage dip and swell. This call for an efficient control operation of DFIG- based WECS to ensure an improved performance under dynamic conditions. The Direct Torque Control (DTC) otherwise known as scalar control technique is a technique best use in DFIG for wind energy extraction due to its better dynamic response, reduce use of machine parameters and its simplicity in implementation. From the work presented, conclusions will be made on the best configuration for WEC system and the control suitable for suppressing torque and regulating flux riffle.