Flexible Arrangement of Static Converters for Grid-Connected Wind Energy Conversion Systems

This paper presents a new flexible arrangement of static converters for grid-connected wind energy conversion systems (WECS). The proposed arrangement uses three-phase voltage-fed back-to-back mass-produced power converter modules with reconfiguration switches. The main features of the proposed flexible arrangement are as follows: 1) expanded reactive power capability limits; 2) high efficiency, mainly under low wind conditions where the active power is reduced; and 3) low current harmonic content. In addition, a detailed description of the operating modes, as well as of the grid, generator, and circulating current controller design, are given. Finally, experimental results support the theoretical development, and demonstrate the good performance and flexibility of the proposed arrangement.