Innovative design of a transmission mechanism for variable speed wind turbines

An innovative transmission mechanism, referred to here as an independently controllable transmission (ICT), for application in variable speed wind turbines is described. This ICT mechanism can transmit rotational output speed that can be independently regulated by a controller and is not affected by the speed of the input shaft. Use of this ICT mechanism would make it possible for a variable speed wind turbine to be unaffected by rotor speed fluctuations and allow the generation of constant frequency electrical output of improved quality. The ICT mechanism is comprised of two planetary gear trains and two transmission-connecting members. The kinematic, static characteristics, and power flow of the ICT mechanism have been analyzed and derived as analytical equations. Demonstration examples and a prototype of the device have been built and tested to examine their kinematic and static characteristics and to verify the validity of the results.