变速风力发电系统瞬态载荷分析及其优化设计途径

Way to Optimally Design Transient Load of Variable-Speed Wind Energy Conversion System

为了提高风力发电系统捕获的风能,在额定风速以下,需要对机组实施最大功率跟踪控制。目前大多数关于最大功率跟踪控制策略的研究均集中于提高跟踪的速度。然而,本文的研究发现,最大功率跟踪速度的加快将使机组承受更大的瞬态载荷,使传动链更易疲劳损坏。首先通过对最大功率跟踪的速度及承受的瞬态载荷进行定量分析,找出了机组承受的瞬态载荷与最大功率跟踪速度的定量关系。之后,为了优化设计机组的瞬态载荷,提出了最大功率跟踪控制系统的跟踪带宽的设计原则。且为了使机组可按优化设计的跟踪带宽恒带宽运行,提出了保持最大功率跟踪带宽恒定的方法。最后,在实验室内建立了一套1.2k W的变速风力发电系统,实验结果验证了理论分析的正确性。

In order to increase the annual energy yield of variable-speed wind energy conversion system(WECS), maximum power point tracking control is usually required below rated wind velocity. However, most of the researches only paid their attention to the way to fasten the MPPT speed. In fact, the research of this paper find out that the faster the maximum power point tracking(MPPT) speed is, the larger the transient load the turbine shaft bears. Thus, attempts are firstly made in this paper to find out the relationship between the MPPT speed and the transient load the shaft bears through quantity analysis. Then, principle to design MPPT bandwidth is given out to optimize the transient load. To make the WECS can operate under the designed MPPT bandwidth, the design details on how to make the MPPT bandwidth constant is further given out in this paper. Finally, a 1.2k W variable-speed WECS is established in the laboratory. Theoretic analysis is verified by experimental results.