In this article, a fractional order sliding mode fault-tolerant controller is suggested for the converter of rotor side of a doubly-fed induction generator (DFIG). The suggested controller is obtained by combining the fractional calculus and sliding mode control, and closed-loop fractional order system stability is proven using Lyapunov theorem. A model of full-order observer based on estimation algorithm of the rotor current is used for a better performance against the errors generated in the sensors of rotor current. Simulations are accomplished in normal performance conditions in order to illustrate the suggested fractional order method superiority over classical sliding mode control method. The suggested method is also examined under the condition of error occurrence in the sensors of rotor current, and the outcomes are compared under error and without error conditions. The suggested fractional-order sliding mode method has some advantages, including signal chattering reduction, faster and more accurate tracking response, shorter convergence time to sliding surface, robustness to uncertainties and external disturbances.