Patent ID: 7863767

Claim:
A turbine driven electric power production system ( 1 ), comprising a turbine ( 2 ) arranged for being driven by a fluid ( 3 ) having a fluid speed (v) varying in time, said turbine ( 2 ) connected to a hydrostatic displacement pump ( 6 ) further connected to a hydrostatic displacement motor ( 8 ) as part of a hydrostatic transmission system ( 7 ), said motor ( 8 ) arranged for driving an electrical generator ( 9 ) supplying AC power ( 10 ) at a frequency (f g ) near a given desired frequency (f des ), characterized by a closed loop control system ( 15 , 15 a ) arranged for continuously receiving a speed signal ( 11 ) representing the speed (v) of said fluid ( 3 ), from a fluid speed meter ( 11 m ), and further arranged for continuously receiving a turbine rotational speed signal ( 12 s ) representing the rotational speed measurement (Ï‰) of said turbine ( 2 ), from a turbine rotational speed sensor ( 12 m ), based on said wind speed and turbine rotational speed signals ( 11 , 12 s ), calculating a control signal ( 16 ) for a volumetric displacement control actuator ( 17 ) on said hydrostatic motor for continuously adjusting a volumetric displacement (d) of said hydrostatic motor ( 8 ), so as for enabling to maintain a set turbine tip speed ratio (tsr set ) and thereby achieving an improved power efficiency of the power production system ( 1 ) during fluctuations in said fluid speed (v).