Novel Modeling and Control of Doubly-Fed Variable-Speed Constant-Frequency Wind Power Generator

Reasonable modeling and control is of significance for theory study and practical operation of doubly-fed variable speed constant frequency (DFVSCF) wind power generator. Two sorts of simulation models called no-load model and generation model were obtained through linearization and discretization of the state equations of doubly-fed induction generator (DFIG), which was derived from the DFIG model in synchronously rotating reference frame. Both models work in coordination one after another to achieve the whole simulation of DFIG before and after grid-connection. Based on the field-oriented vector control technique, the decoupling control of output power of DFIG, together with grid synchronization, was investigated. The maximum power point tracking (MPPT) was realized by control of DFIG active power. The simulation results, which are highly consistent with the experiment results, verify the validity and correctness of the theoretical analysis and control strategy proposed by this paper.