Abstract: The present invention provides a controllable compound rotor system for the WECS, with a pilot rotor working under low wind speed conditions and a main rotor working under high speed conditions. By proper switching of the clutch, the WECS can not only achieve a greater starting torque under low wind speed conditions, as well as to capture and utilize the low wind-speed wind energy after being started, but also give full play to the advantage of the main rotor having the excellent wind capturing efficiency under high wind speed and high turning speed conditions. Thus the WECS can capture and utilize wind energy under both low and high wind speed conditions, which greatly expands the speed and zone range wherein the WECS can be applied, facilitating wide application of the WECS.

Abstract: The present invention discloses a rotor of wind energy conversion system (WECS) with the Venturi-tube effect. All the blades mounted on the blade-mounting seat envelop together to form a revolving-body cage turbine, which can be divided from structure into a head portion at the windward end, a tail portion at the wind exhaust end, and an airstream compression portion between the head portion and the tail portion and constituted by the enveloping blades. The revolution diameter of the airstream compression portion is gradually substantially increased from the head portion to the tail portion. The cage turbine forms a dynamic Venturi tube during the revolving process, with which the blade revolves to constitute its outline tube wall with the air permeability. The airstream passes through a window between the blades, and the incoming wind does work towards the blade during the process of permeating from the external space to the internal space of this outline tube wall, thus realizing the energy transfer.