A low cost grid interface for DFIG using SPWM technique

Grid integration of a laboratory scale Doubly Fed Induction Generator (DFIG) has been carried out and reported here. The stator of the DFIG is directly connected to the grid and the rotor is interfaced to the grid through a pair of back to back converters (rectifier and inverter). A low cost control scheme using sinusoidal pulse width modulation (SPWM) technique is used in the inverter to match the rotor voltage, phase and frequency with those of the grid and also to facilitate power transfer by creating a phase shift. Complexity in the interface controller is avoided as it allows only super synchronous generation. The scheme has been successfully validated in laboratory and the results are presented here.