扩展MPPT运行区间的双馈风电机组智能双模控制策略

Intelligent Dual-mode Control Strategy for Extending MPPT Operation Interval of DFIG Based Wind Turbines

为扩展双馈型感应发电机(DFIG)最大功率点跟踪运行区间,提高其在低风速区间的发电效率,首先,文中提出了一种智能双模控制策略,通过机侧变流器控制策略的调整以及必要的开关切换,DFIG可根据风速不同自动地运行于两种模式:传统DFIG模式及DFIG定子短路模式。然后,针对模式切换过程时间短的需求以及冲击大、影响久的特点,重点研究了文献鲜有提及又极为重要的模式柔性切换控制方法,特别是双向模式切换的具体流程、机侧变流器控制策略以及发电机负载的选取等。最后,基于RT-lab的硬件在环仿真结果表明,所提控制策略较好地发挥了DFIG的成本优势与全功率型发电机的宽变速范围优势,并实现了两种模式的快速、柔性切换。

To extend the operation interval of maximum power point tracking(MPPT)of doubly-fed induction generator(DFIG)and improve the power generation efficiency with low wind speed interval,an intelligent dual-mode control strategy is firstly proposed.With adjustment of the strategy on the machine side converter(MSC)and the necessary switchover,the DFIG can automatically operate in two modes depending on the wind speed:the traditional DFIG mode and the stator short-circuit(SSC)mode.Then,to satisfy the requirement of short switching time and address the issues including huge impacts and long-time influences during the mode-switching process,this paper focuses on the flexible mode switching control methods,especially the specific procedure of bidirectional mode switching,MSC control strategy and the selection of generator load,which is rarely studied in previous literature.Finally,the hardware-in-the-loop experimental evaluation based on the RT-lab demonstrates that the proposed strategy effectively takes advantages of both the low cost of DFIG and the wide speed range of full-power generator,which achieves efficient and flexible switching between the two modes.