中文摘要：

国家标准对并网风机在故障期间的低电压穿越能力提出了技术要求,即能在电压跌落一定范围内不脱网运行,并提供动态无功支撑。为了提高双馈风电机组的低电压穿越能力,提出了基于状态相关Riccati方程（state-dependent Riccati equation,SDRE）的控制器。SDRE控制器具有灵活的设计方式,可以通过实时优化状态相关系数矩阵,提升暂态响应性能,实现被控对象在较大范围内的渐近稳定。针对双馈风电机组设计了SDRE控制器,并通过与Crowbar的配合,实现了符合国家标准的低压故障穿越策略。通过算例系统在三相故障下的仿真,验证了所提控制策略相比常规PI控制策略以及故障期间持续投入Crowbar的策略,能够更好地实现低电压穿越。

英文摘要：

Integrated wind turbines are required to have LVRT ability during grid fault according to Chinese national standards, i.e., they are supposed to remain grid-connected within certain realms of voltage sag and offer dynamic reactive power support, etc： In order to improve LVRT ability of DFIG, a controller based on state-dependent Riccati equation （SDRE） is proposed in this paper. Due to its design flexibility, SDRE controller can optimize system＇s dynamic response and guarantee asymptotic stability in a large scope through real-time optimization of state-dependent coefficients. For DFIG, this paper proposes SDRE controller in cooperation with active crowbar circuit to comply with national standards. In comparison with commonly used PI controller and strategy of crowbar circuit being continuously on during the fault, simulation under three phase fault shows that the proposed control strategy has better LVRT performance.