This paper presents a new gain scheduling speed controller of permanent magnet synchronous generators(PMSG) for MW-class direct-driven wind turbine systems. The proposed gain scheduling speed controller performs the speed tracking at more than one operating point, and the first-order torque observer estimates the turbine torque which is needed to precisely control the speed of PMSG. The proposed speed controller verifies that the PMSG can successfully follow the reference speed which is determined via the maximum power point tracking(MPPT) control and pitch control under turbulent wind conditions. The proposed speed control algorithm is simulated using Simulink and its performance is confirmed through comparison with the results by PI control method.