A wind power plant where the driving shaft communicates with a synchronous generator (3) optionally through a gear (2) and with a transformer, if any, communicating through an AC/DC inverter 7 with an HVDC transmission cable 9. The synchronous generator (3) is connected to a magnetic field controller (3). In response to an output parameter, such as the power generated by the synchronous generator (3), this magnetic field controller (4) is adapted to vary the magnetic field in the generator (3) in response to said output parameter. As a result it is possible to compensate for a possible variation in the output parameter, whereby said output parameter is stabilized. As a result it is possible to compensate for a varying speed of rotation.