摘要
针对永磁直驱风电系统网侧换流器模型存在非线性和强耦合的特点,提出了一种非光滑控制和反推控制相结合的混合控制策略。在dq两相同步旋转坐标系下建立网侧换流器非线性数学模型,采用非光滑控制理论和反推控制方法分别设计了外环直流电压控制策略和内环电流控制策略。在外环控制方面,通过结合非光滑理论的有限时间控制方法和扩张状态观测器(extended state observer,ESO)对于系统扰动的估计作用,设计了直流电压控制器。在内环控制方面,采用附加扰动补偿的反推控制方法进行设计,利用扩张状态观测器对外部扰动造成的系统内环不确定因素进行估计,将估计量引入到反推迭代控制律的设计中进行补偿,通过选择合适的Lyapunov函数,推导出内环电流反推控制律,使内环系统满足Lyapunov渐近稳定条件。仿真结果表明,与常规的PI线性控制策略相比,所提混合控制策略能够有效提高永磁直驱风电系统在电网扰动时的并网动态特性。
According to the nonlinear and strong coupling characters of the grid-side converter model of direct-driven permanent magnet synchronous generator （PMSG） based wind power generation system, this paper proposes a compound control strategy which combines the non-smooth control and back-stepping control. Based on the nonlinear mathematical model of the grid-side converter in dq synchronous rotating coordinate system, the grid-side outer-loop of DC voltage control strategy is designed by using non-smooth control principle and the inner-loop of current control scheme is designed by using back- stepping control method. In the aspect of outer-loop control, the DC voltage controller is designed by combining the finite-time feedback control method of non-smooth principle and the system disturbance estimation effect of extended state observer （ESO）. The back-stepping control approach with additional disturbance compensation is applied in the inner-loop current control. By adopting ESO to estimate the uncertainties of system inner-loop caused by external disturbances, the back-stepping iterative control law is designed with the introduction of the estimated uncertainties for compensation. The appropriate Lyapunov function is established to obtain the principle of the inner-loop back-stepping current control, which makes the inner- loop system meet the Lyapunov asymptotic stability condition. The simulation results show that, compared with the conventional PI linear control strategy, the presented compound control strategy can effectively improve the grid-integration dynamic response performance of PMSG-based wind power generation system under the grid disturbance conditions.
出处
《电力建设》
北大核心
2017年第6期133-141,共9页
Electric Power Construction
基金
国家重点研发计划项目(2016YFB0900101)~~
关键词
永磁直驱风电系统
网侧换流器
混合控制策略
非光滑控制
反推控制
扩张状态观测器(ESO)
direct-driven permanent magnet synchronous generator based wind power generation system
grid-side converter
compound control strategy
non-smooth control
back-stepping control
extended state observer（ESO）
