A six-phase wind energy induction generator system with series-connected DC-links

The paper presents a study of a six-phase wind energy conversion system (WECS) with series-connected dc-links. The structure of the generation system requires the dc-link voltages to be balanced at the generator´s side. To achieve this, it is shown that a dc-link voltage balancing controller can be realised by exploiting the extra degrees of freedom provided by the xy plane of the six-phase machine. To facilitate the controller´s implementation, an alternative modified transformation matrix is also suggested. The feasibility of the studied system, including the operation of the dc-link voltage balancing controller, is verified using Matlab/Simulink simulations.