This paper describes a second-order sliding mode control for a permanent magnet synchronous generator-based marine current turbine dealing with the generator-side converter faulty conditions. Marine turbine system mainly used PI controllers. However, this type of controllers is unfortunately very sensitive to faulty conditions as those affect the system converter. In this faulty context, the marine turbine system power generation and dynamic performances are highly degraded. In order to maintain a minimum of optimal performance, second-order sliding modes are therefore investigated for fault-tolerant control purposes.