Low voltage ride through of doubly fed induction generator in wind power generation using crowbar solution

The main advantage of the doubly fed induction generators (DFIG) over the synchronous generators is the small size converter which is located in the rotor circuit. However, this advantage can cause a problem during grid faults, because the over voltages and currents that will occur on the rotor circuit can damage the rotor side converter (RSC), if it is not over-dimensioned or protected for such high voltages and currents. Crowbar protection is a quite common solution of the grid faults for DFIG, the crowbar connects small resistances to the rotor terminals of the generator in order to limit voltage and current peaks; the RSC is disconnected as long as the crowbar is active. In this situation the DFIG is still connected to the grid and support it with a reactive power to fulfill the grid codes. A simulation study of different types of grid faults will be carried out in MATLAB/SIMULINK environment.