Fixed speed wind turbines are a type of wind turbine that operates at a constant rotational speed, regardless of the wind speed. The basic principle behind these turbines is to convert the kinetic energy of the wind into mechanical energy, which is then converted into electrical. What is a variable speed wind generation system? As compared to the fixed speed wind generation systems, the variable speed wind generation systems produce more power [6,46,47] and provide less stress on the generator shaft, as the shaft speed can vary with the variation of wind speed. This fundamental difference impacts the study of these two types of machines: under the simplest of assumptions of constant wind speed, constant rotation speed and isolated rotor (neglecting support interference), the flow. As an outgrowth of operating large, more complex propellers, a variable-pitch, constant-speed feathering and reversing propeller system was developed. This system allows the engine rpm to be varied only slightly during different flight conditions and, therefore, increases flying efficiency.
