Indirect Vector Control for Stand-alone Operation Brushless Doubly Fed Induction Generator Employing Power Winding Stator Flux Orientated Approach

The brushless doubly-fed induction generator (BDFIG) provides an interesting alternative to the commonly applied conventional doubly-fed induction generator in wind turbines. In this paper, a novel voltage control strategy of stand-alone operation BDFIG for variable speed constant frequency wind energy conversion systems was presented. Based on the model of the generator, the power winding stator voltage and flux for stand-alone operation BDFIG are only determined by the equivalent PW stator magnetizing current which are independent of load, but PW stator terminal output power is only determined by load. An indirect PW stator flux orientated vector control scheme is employed to control the BDFIG by regulating the amplitude and frequency of the control winding stator current appropriately, and this results in constant generator terminal voltage and frequency for variations in both load and wind speed. In addition, simulation results prove the feasibility and validity of the proposed scheme, and excellent steady and dynamic state performance is achieved. (paper)