Wind energy conversion system

Abstract

A wind powered device on a support structure is provided with a drive shaft mounted for rotation about its axis on the support structure and is coupled to an electric generator connected to a utility power grid. A rotor is mounted on the support structure and is adapted to drive the shaft, hence the electric generator. The rotor has at least one rotor blade. The rotor is mounted to drive the shaft and also for limited relative rotational movement with respect to the drive shaft about the axis of the drive shaft as the wind velocity driving the rotor changes. The coupling between the shaft and rotor responds to increases and decreases in rotor torque so that as imbalances between shaft torque and rotor torque arise, the rotor tends to run ahead of or behind the shaft. That causes rotation of the rotor relative to the drive shaft and the coupling means sense that change and automatically increase or decrease blade pitch via the automatically responsive mechanical coupling means to tend to bring shaft torque and rotor torque back into balance. Desirably the shaft is governed by a speed regulator, such as a generator connected to a utility power grid, so that it will rotate up to a predetermined speed or speeds beyond which shaft torque tends to increase sharply, so that if the speed of rotation of the rotor increases to a point at which it tends to exceed maximum permitted shaft torque, the blades are automatically increased in pitch which then decreases rotor speed, hence rotor torque. Several embodiments for automatically mechanically adjusting blade pitch in response to changes in rotor torque and imbalances in rotor and shaft torque are disclosed.