Comparison of different types of electromechanical systems for creating the counter-rotating VAWT

The article presents a comparison by computer simulation the work of dual-rotor vertical axis wind turbine (VAWT) with three types of mechanical transmissions: rigid with the bevel gearbox, semi-rigid with the differential, and soft gearless with the double rotor synchronous generator with permanent magnets. The results of the study have shown the advantages and disadvantages of dual-rotor VAWTs with these transmissions on their start and operation in real conditions that can be characterized by different values WTs moments of inertia and wind gusts at different speeds acting on each of wind turbines (WT). The existence of the backlashes between the gears in rigid and semi-rigid mechanical transmissions causes significant ripples of elastic torques, which are larger in transmission with differential than in gear transmission. This drawback is absent in gearless transmission, making it the most promising to the application in small counter-rotation VAWTs.