A hybrid excitation synchronous generator for a 1.5 MW grid-connected wind conversion system.

The purpose of this paper is to introduce a complete wind conversion system based on a hybrid excitation synchronous generator (HESG) for large-scale 1.5 MW, grid-connected wind turbines. The proposed architecture should be tested under realistic operating conditions. However, for this power, setting up an experimental test bench would require exceptional funding for the laboratory and a great expertise. So, instead, advanced software simulation tools are used. In this work, an integrated near-realistic simulation model is developed. Both, the harmonics of the generator and the aerodynamics of the wind turbine are modeled. To ensure an optimal operating of the aerogenerator, a CRONE robust control approach is adopted. It is used for the generator's velocity loop controller and for the pitch control loop. Comparisons with a robust H∞ controller and a PI-based fuzzy controller are presented. Both control loops are tested under severe loads and stochastic wind profile. It is shown that an efficient control is achieved. Then, two scaled down power electronic interfaces using both, multilevel and conventional inverters, are implemented and investigated in terms of cost and performance. A Cascade H-bridge three-level inverter is chosen as it offers a good total harmonic distortion (THD) using a simple modulation technique without an extra filter to connect to the grid. Results show that the proposed architecture can be used to conduct performances-based comparisons to similar wind systems based on other types of generators such as permanent magnets synchronous generators and doubly fed induction generators. [ABSTRACT FROM AUTHOR]