Advantages of ac-ac power converters based on ANPC topology for wind applications

Wind energy conversion systems (WECS) are increasingly higher due to the great demand of wind energy. Thus, the power converter will play a more important role in the next generation of large WECS. Currently, the most accepted ac-ac power converter for WECS is the conventional twolevel back-to-back (2L-B2B). However, 2L-B2B is expected not to provide an acceptable performance for the largest offshore WECS with the available switching devices. Therefore, the wind market is open for the multilevel power converters, among which three-level neutral-pointclamped (3L-NPC) topology is achieving interesting high wind market penetration. However, 3LNPC enables some improvements regarding 2L-B2B, but it provides some intrinsic drawbacks as the uneven power losses distribution. Lately some investigations has been focused on analyzing the three-level active neutral-point-clamped (3L-ANPC) which provides enhanced features compared to the 3L-NPC thanks to replace the clamping diodes by bidirectional switching devices. Thus, 3LANPC can be understood as the natural evolution of the 3L-NPC.