A novel approach for crowbar resistance determination for doubly fed induction generators in wind energy conversion systems

Abstract

ABSTRACT This paper presents a novel approach for determination of the crowbar resistance of the doubly fed induction generator (DFIG) in wind energy conversion system (WECS) that is used to improve the fault ride through (FRT) capability of the generator during the grid voltage dips. According to the new grid codes, the DFIG must remain connected to the grid during the grid disturbances. A crowbar protection is utilised to improve the DFIG FRT capability. The crowbar resistance of the DFIG should be carefully selected to maintain the rotor voltage within its safe limits during the grid disturbances. In this paper, the value of the crowbar resistance as a function of the slip is obtained based on the dynamic behaviour of the DFIG rotor voltage during voltage dips in the grid. The function is obtained by simulating the model under different operating speeds and by utilising different crowbar resistance values.