Variable speed wind turbine based on electromagnetic coupler and its experimental measurement

In variable speed wind turbine based on electromagnetic coupler (WT-EMC), synchronous generator is directly coupled with grid. Electromagnetic coupling speed regulating device (EMCD) is used to connect the gearbox high speed shaft and synchronous generator rotor shaft, and achieve the torque transmission. Compared with common variable speed wind turbines nowadays, WT-EMC has better transient overload capability, fault ride-through (FRT) and voltage support capability, and inherent frequency support capability in terms of power system regulation, due to the synchronous generator directly coupled with grid. The novel drive train of WT-EMC results in its new control strategy. In this paper a 1.5 MW WT-EMC experimental platform is built to measure the EMCD transmission efficiency under various operating conditions and the effectiveness of the new WT-EMC control strategy for start, synchronizing and connecting to grid, stop is investigated on a reduced power rating 30 kW experimental platform built in the lab.