This paper investigates the performance of a direct-driven fully superconducting generator (FSG) utilized in wind energy conversion system (WECS) over a wide range of operating conditions. The system under study consists of a FSG driven by a wind turbine and connected to the grid through a back-to-back voltage source converter and a DC link capacitor. The investigation includes studying the effects of wind turbine control systems as well as control techniques for both generator-side and grid-side converters on the system performance. The steady-state performance of the FSG is analyzed with wind speed variation. The system is subjected to various disturbances including 3-phase short circuit fault, line-outage disturbance and step change in wind speed. PI controllers are used to improve the system stability and enhance its performance. The optimal set of the controllers' parameters is obtained using the particle swarm optimization (PSO) technique. Simulation results show that the system performance is well improved with the proposed controllers under various disturbances and operating conditions.