A new crowbar protection method for improvement in performance of doubly fed induction generator under fault conditions

This paper presents a new method for increasing the doubly fed induction generator (DFIG) performance under fault conditions. After the fault takes place, the rotor current increases to more than 8 times the nominal value, so the protective resistors called crowbar (Cb) will be switched on, and the current will be restricted. In order to stop injuring the rotor side convertor (RSC), the control signals of the switches are getting turned off; however, by the use of the proposed method the proper value for crowbar is chosen, and the RSC is connected to these resistors. As a result, the dc link voltage fluctuations will be limited, and the DFIG can continue supplying active and reactive power to the grid. All the simulations are carried out in Matlab, Simulink and m-file.