双馈风电机组的非线性变结构功率解耦控制

Decoupled Control Strategy of Active and Aeactive Power Based on Variable Structure Theory for Wind Power Double-Fed Induction Generator

双馈异步电机的传统矢量控制中,其转子侧的反电动势引起的电压交叉耦合补偿项会使控制器无法实现对系统有功无功的完全解耦控制,且传统矢量控制过于依赖电机参数,导致其控制性能对电机参数变动和外界扰动比较敏感。为此,采用精确线性化理论的解耦控制方法,以更准确地反映双馈异步电机的时变强耦合的高阶非线性系统特性;又考虑到双馈异步风力发电机组运行于风速不可控且随机性较强的环境中,而传统PI控制器的调节过程相对滞后且超调量较大,影响动态响应特性,所以采用动态响应特性较好且对外界干扰和参数摄动具鲁棒性的滑模变结构控制理论来设计控制器。仿真结果表明,所提解耦控制方法可以实现定子有功无功的完全解耦和鲁棒控制,且控制器有良好的动态调节性能。

In traditional vector control of double-fed induction generators（DFIGs）,voltage cross-coupling compensation caused by counterelectromotive force of the rotor side makes the active and reactive power of the system cannot be decoupled completely.Moreover,traditional vector control relies on parameters of DFIGs heavily,which makes its control performances sensitive to the parameter variations and external disturbances.So,the exact linearization theory of decoupling control method is applied,which can reflect the time-variation strong-coupling characteristics of the high-order nonlinear system more accurately.In addition,taking account of the operation environment of the uncontrolled and strongly random wind speed,which makes the adjustment process of the traditional PI controller excessively lag behind and affect the dynamic-response performances,the sliding mode variable structure control theory is applied to design the controller with good dynamic-response and robustness against outside interferences and parameter uncertainties.The simulation results show that the proposed decoupling control method can make the controller achieve complete-decoupling and robust control of the active and reactive power with good dynamic-performance.