Flexible Grid-connection Technique and Novel Maximum Wind Power Tracking Algorithm for Doubly-Fed Wind Power Generator

The connection between the doubly-fed wind power generators (WPGs) and the grid affects the security of the grid and generator. The maximum. wind power tracking (MWPT) affects the efficiency of the generators connected to the grid. This paper deals with two problems above. Based on a no-load model of doubly-fed induction generator (DFIG), and by applying a vector control technique called stator flux orientation vector control technique (SFOVCT), a grid-connection control strategy for doubly-fed WPGs is developed. According to the wind turbines (WTs) principles and DFIG power characteristics, the paper investigates the MWPT principles based on generator power control, and then introduces an algorithm for active power command of the DFIG. Based on SFOVCT and general-purpose model for DFIG, this novel algorithm enables decoupled output power of DFIG, and then an integrated control strategy for MWPT are developed The grid-connection and the MWPT for the DFIG are presented for a 15-kw laboratory set up, and the experiment results verified the validity and feasibility of the theoretic analysis, as well as the control strategy.