Back-to-back wind energy conversion system configuration based on 9-switch dual converter and open-end-winding PMSG

The following work introduces the use of a dual three-phase converter with reduced number of switches in a back-to-back configuration for its application to an open-end-winding permanent magnet synchronous generator based wind energy conversion systems (WECS). The converter topology consists of a nine-switch dual three-phase voltage source converter capable of controlling two sets of three-phase variables without voltage limitations when operating both three-phase systems at same frequency. This feature is exploited to control both ends of the PMSG and the three phase inputs of a 12 pulse transformer witch connects the grid. The open-end winding generator connection provides more space vectors for control while the 12 pulse grid-connection enables mitigation of switching harmonics.