Study of brushless doubly-fed control for VSCF wind power generation system connected to grid

A whole model for brushless doubly-fed wind generation system is presented and the model in includes wind turbine, gear-box and brushless doubly-fed machine (BDFM). Starting from d-q model of rotor under reference coordinate, a mathematical model of BDFM based on synchronous coordinates is researched. For the power system, a new model adapting to analyze the power system is gained by neglecting the electromagnetic transient change. According to the characteristics of BDFM and adopting flux linkage oriented vector transformation control technology, a new type of control for brushless doubly-fed VSCF wind power generation system connected to grid is developed. The doubly-fed control is adopted in this system, and the voltage compensate is avoiding for the PWM current-tracing control is used in the inner ring. By means of controlling the control winding of wind turbine this control system the AC excitation is implemented, and then the decoupling control of active and reactive power is realized, eventually the generating operation mode with high efficiency that can capture maximal wind energy is come true. Simulation results verify the availability and validity of the proposed control strategy.