Abstract: A wind turbine system is disclosed comprising: a plurality of turbine blades; a continuously variable transmission coupled to said plurality of turbine blades; a generator coupled to said continuously variable transmission; wherein said generator generates electricity and outputs said electricity to a load/grid; and a controller providing control signals as a filtered function of power to said continuously variable transmission. The controller of said wind turbine system may also continuously maintain the parameter dP/dR substantially zero where P is power and R is the ratio of the transmission.