An Intelligent Dual-Mode Control Strategy for Extending MPPT Operation Interval of DFIG

摘要

An intelligent dual-mode control strategy is proposed to extend the MPPT operation range of doubly-fed induction generator (DFIG) and improve the power generation efficiency under low wind speed in this article. By adjusting the strategy of the machine-side converter (MSC) and the necessary switchover, DFIG can automatically operate in two modes depending on the wind speed: the traditional DFIG mode and the DFIG stator short circuit (SSC) mode. In addition, aiming at the characteristics of short time, large impact, and long impact of mode switching process, this article focuses on the flexible mode switching control methods rarely mentioned in other studies, especially the specific process of bidirectional mode switching, MSC control strategy, and the selection of generator load. Finally, the hardware-in-the-loop (HIL) simulation results based on RT-lab show that the control strategy proposed in this article takes the advantages of the low cost of DFIG and the wide speed range of full-power generator (FPG), and achieves fast and flexible switching between the two modes.