Patent ID: 8502406

Claim:
A variable-speed power generator comprising: (a) a prime mover that generates motive power by using natural energy, (b) a wound-rotor induction generator that (b1) includes a stator having a primary winding and a rotor having a secondary winding, the stator and the rotor being connected to a power grid, and that (b2) generates electric power based on the motive power generated by the prime mover, (c) a power converter connected to the stator and the rotor, and (d) a controller which controls wound-rotor induction generator, (d1) wherein the controller responds to instructions for supplying reactive power to the power grid, said instruction being sent by the power grid, and (d2) wherein the response of the controller to an instruction for supplying reactive power to the power grid may include (d2a) imposing limitations on the reactive power supplied by the power converter to the power grid and (d2b) causing the wound-rotor induction generator to operate at a rotation speed set to be higher than or equal to a synchronous speed.