Novel Integration of a PV-Wind Energy System With Enhanced Efficiency

A novel integration scheme of solar photovoltaic (PV) with a large capacity doubly excited induction generator-based wind energy system is described. The proposed scheme uses both the grid- and rotor-side power converters of doubly fed induction generator to inject PV power into the grid. Thus, it renders a cost-effective solution to PV-grid integration by obviating the need for a dedicated converter for PV power processing. The system is able to feed significantly large PV power into the grid compared to an equivalent rating inverter used in the conventional PV-grid system. The proposed scheme prevents circulating power during subsynchronous operation during the availability of solar radiation. All these features enhance system efficiency. System stability is also augmented due to turbine inertia, facilitating high PV penetration into the power grid. The intermittent but complementary nature of solar PV and wind energy sources considerably improves the converters´ utilization. Besides, the proposed scheme does not hamper maximum power point tracking of PV and wind sources except during very rarely occurring environmental glitches, which the PV power control algorithm is suitably geared to handle. A comprehensive system model is presented and used for designing the control strategy. The proposed scheme is supported by analysis, simulations, and experiments on a laboratory prototype.