Elements of modelling of wind power systems with energy management: two structures in comparison

In order to study the influence and the impacts of the grid connection of wind generators, and to predict problems which can occur, modelling plays a very important role. In this paper, a particular attention is focused on the energy management. For this, special models and control algorithms are developed. This paper presents two different wind generator topologies. The first structure is a synchronous machine connected to the grid via an AC-AC converter. This innovating solution, which remains still rather confidential, offers interesting possibilities in term of energy management (active and reactive power). The second structure is an induction machine directly connected to grid associated with a static VAr generator in order to avoid flicker problems and other perturbations. These two topologies are modelled, controlled and compared. First, the various wind generator components are modelled such as wind turbine, electric machine, power electronics devices and grid. Particular attention is focused on the various control levels, and on algorithms permitting to manage the system power generation, conversion and transfer. The proposed models and algorithms present the advantages in case of the lack of information such as control system data and control laws. In general, manufacturers only provide commercial data, a lot of details concerning the kind and the size of the wind power generators. Finally simulation results, comparisons for each solution are presented.