Efficiency Analysis of a Planetary Speed Increaser for Wind Turbines with Counter-Rotating Versus Fixed-Stator Electric Generator

The paper presents a comparative study of the efficiency of a planetary speed increaser with spur gears used in wind turbines with one rotor and a counter-rotating electric generator compared to the conventional case (generator with fixed stator). Based on a generalized algorithm proposed for the kinematic and static modelling of the speed increaser with one input and two outputs, the efficiency is obtained for both cases of power flow transmission: branching on two outputs and without branching (one output). The numerical simulation of the analytical results highlights the higher efficiency of two-output speed increaser from wind turbines with counter-rotating generator compared to the case with one output.