Wave Energy Convertor

A device for generating electric energy from a wave motion, the device comprising a movable element movable under the influence of the wave motion, a main electric generator, a drive train comprising an input branch and an output branch, the drive train being arranged between the movable element and the main electric generator, the movable element imposing an oscillatory movement on the input branch of the drive train as a result of the wave motion, the oscillatory movement being a periodic movement, having a period wherein during alternating moments in time positive and negative speeds are imposed to the input branch, the drive train comprising a power split transmission comprising at least three ports, the at least three ports comprising at least one input port connected to the input branch, at least one output port connected to the output branch and at least one control port, the power split transmission being arranged for distributing power received on the input port to the at least one output port and the at least one control port, wherein the drive train furthermore comprises a variable speed auxiliary electrical machine and a control unit for controlling the auxiliary electrical machine, the at least one control port of the power split transmission being connected to the auxiliary electrical machine and the control unit being configured for controlling power distribution in the power split transmission as to realize a one-way rotation of the main electric generator during the whole period of the oscillatory movement.