Ac-dc converters are widely considered in microgrids as an interface between the ac bus and the renewable energy sources. Due to the intermittent nature of these sources, ac-dc converters are essential in providing a fixed output voltage. Due to their simplicity and ease of implementation, PI-based approaches are commonly used in controlling those converters. However, attractive features of fractional order sliding mode controls (FOSMC) have recently drawn researchers' attention into this approach. This paper investigates the performance of the FOSMC and PID controllers in regulating the dc-link voltage of a doubly-fed induction generator (DFIG)-based wind turbine.