A control scheme of the frequency power converter for a MW wave power station is described in this paper. The system configuration, generator, frequency converter and interface to the local grid are also discussed. The speed control method for maximum power tracking in a variable speed low-head hydro-turbine by using IGBT AC/DC converter is described in details. The power supplied to the utility grid is controlled using PWM voltage source inverter by balancing the input-output power of the dc link. The effect of the torque fluctuation on the output power has been simulated.