新型直接功率控制算法在双馈风电平台的应用

A Novel Direct Power Control Strategy Used in DFIG-based Wind Generation Platform

结合传统双馈发电机(DFIG)矢量控制与直接功率控制,提出了一种基于无差拍控制的直接功率控制策略。该算法结合定子有功、无功功率给定值,在定子电压定向的坐标系下通过无差拍控制直接得到所需电压矢量,既避免了传统双闭环中电流环带宽对系统快速性的不利影响,又克服了传统直接功率控制中开关频率不确定所带来的不便。同时该方法利用电流观测器对电流进行预测,从而提前计算电压矢量,极大地消除了计算延时在系统中造成的滞后。最后通过试验证实了该控制策略的有效性。

A novel direct power control strategy based on deadbeat algorithm is proposed,which is deduced from the PI control strategy and the conventional direct power strategy of doubly fed induction generator（DFIG） wind power system.The expected voltage vector is calculated from the given value of reactive and active power of the generator’s stator under the grid voltage oriented axis.This new method improves the transient performance by eliminating time delay caused by the current loop and outwits traditional direct power control because of the constant converter switching frequency.The predictive current value is calculated by a simple current observer and in this way the expected voltage vector can be predicted one sample period ahead,which eliminates the time delay caused by calculation.The experimental results prove the validity of this method.