基于九开关变换器的双馈风电系统研究

项目名称： 基于九开关变换器的双馈风电系统研究

项目编号： No.51207065

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 电气科学与工程学科

项目作者： 陈宇

作者单位： 华中科技大学

项目金额： 26万元

中文摘要： 在目前的双馈风电系统中，双馈电机转子绕组通过背靠背变换器与电网连接，在此结构下实现低电压穿越（LVRT）需增加辅助电路或额外的器件容量，这导致了系统成本的增加和正常运行时容量的浪费。为解决上述问题，本项目在用九开关变换器代替背靠背变换器后,提出器件容量的动态分配思路。通过九开关变换器额定容量在网侧与转子侧支路的动态实时分配，无需增加辅助电路和额外器件容量即可实现双馈风电系统的正常运行、故障穿越以及电压恢复过程中对电网的动态无功支撑。本方案使九开关变换器的额定容量在正常与LVRT过程中均得以充分利用，有利于减少成本，提高功率密度。除了为双馈风电系统增加新的解决方案和技术储备外，本方案还可在风电并网中发挥积极作用,具有广阔的应用前景。

中文关键词： 风力发电；双馈感应电机；低电压穿越；九开关变换器；控制策略

英文摘要： The rotor of the doubly-fed induction generator is connected to the grid by the back-to-back converters in the recently doubly-fed wind-power generation system, based on which the realization of low voltage ride-through (LVRT) requires the auxiliary circuits or additional component capacities, and thus increases the cost of the system and wastes the capacities in normal situation. To solve this problem, this study proposes the component-capacity-dynamic-assignment conception after the replacement of the back-to-back converters with the nine-switch converter. By assigning the rated component capacities of the nine-switch converter to its grid- and rotor-side branches dynamically in real-time, the normal-work, ride-through after grid failure and reactive power support during grid recovery can be realized without any auxiliary circuits and additional component capacities. With the proposed solution, the rated component capacities of the nine-switch converter can be fully used, in favor of low cost and high power density. Besides providing the new solution and technology backup for the doubly-fed wind-power generation system, the proposed solution could also play an active role in the grid integration of wind energy system and have the wide application prospect.

英文关键词： wind power generation；doubly fed induction generator；low voltage rising through；nine switch converter；control strategy