Vertical axis wind turbine

A vertical axis wind turbine having a vertical rotor apparatus,

• wherein a shaft of the vertical rotor apparatus rotates in response to wind,
• wherein the shaft is configured to transfer mechanical energy from the vertical rotor apparatus to a generator, and
• wherein the vertical rotor apparatus comprises:
• the shaft defining an axis of rotor rotation;
• a plurality of rotor blades longitudinally aligned in parallel with the shaft, each rotor blade defining an axis of blade rotation, wherein each rotor blade is attached to the shaft by an upper strut attached to an upper end of the rotor blade and a lower strut attached to a lower end of the rotor blade through an attachment point serving as an axis of rotor blade rotation;
• a sensor to determine whether any of the rotor blades are within rotor azimuthal angles of blade stall regions, wherein the sensor comprises:
• a fluid vane configured to indicate wind direction;
• contact wires connected to the fluid vane and displaced with rotation thereof, the contact wires defining blade stall regions as a function of the wind direction;
• and
• a contact sensor mounted proximally to the shaft and moving through azimuthal angles therewith, the contact sensor generating a signal in response to contacting the contact wires;
• a controller to provide blade pitch information for the blade stall regions;
• and
• an actuator mechanically coupled to each of the rotor blades to alter blade pitch about the axis of rotor blade rotation in accordance with the blade pitch information so as to avoid blade stall for all rotor azimuthal angles.