A comprehensive control strategy for variable-speed constant-frequency wind power generation

The vector control technique is applied in doubly fed induction generator (DFIG) according to the characteristic of AC-excited variable speed constant frequency (VSCF) wind power generation, a comprehensive control strategy is presented based on grid voltage orientation, which gets the same performances as stator flux orientation, but the stator flux observer can be omitted to simplify the control strategy. The models of flexible cutting-in, running in ready state and grid fault ride-through are established respectively, cutting-in grid without overshoot current is realized in a wide speed range, decoupling control of stator side active power and reactive power is obtained and maximum power point is tracked. In the VSCF wind power generation system, stator and grid are connected flexibly, simulation and experimental results confirm the accuracy and validity of this control strategy.