Investigation of self-excited induction generators for wind turbine applications

To realize a reliable system, a wind turbine must be connected to the utility grid. The squirrel-cage induction generator is a common choice for wind applications. An AC/DC/AC converter is used as an interface to connect the wind turbine to the utility grid to adjust the generated voltage to the utility grid voltage. Moreover, it can allow the generator to work at the required condition of maximum power extracted from the wind turbine. To simplify the analysis, a simple equivalent circuit is proposed to represent the AC/DC/AC converter scheme and the grid as seen by the induction generator. The steady state performance of the self-excited induction generator is investigated and discussed. This analysis is based on the condition of operating the system not only on the extraction of the maximum power of the wind turbine, but also on the maximum induction generator efficiency.