| abstract |
In a wind turbine system 10, a turbine 26 is arranged to be driven by the wind for rotation about a vertical axis. A continuously variable gearbox 34 has an input 14 arranged to be driven by the turbine 26 about the vertical axis. An electrical generator 46 and a flywheel 56 are arranged to be driven by an output 18 of the gearbox. One or more detectors, such as an anemometer 20 and a tachometer 62 for the generator 46, detect at least one parameter related to the system. A control unit 24 controls the gear ratio of the gearbox 34, and the excitation of the generator 46, in dependence upon the detected parameter(s), for example to maximise the power extracted by the turbine 26 from the wind and to maximise the efficiency of the generator. The system is highly efficient despite variations in the wind speed, is not susceptible to the particular direction in which the wind is blowing, and can employ any of a number of different types of electrical generator. |