一类不确定变速风力涡轮机系统的实际跟踪控制

本文研究一类不确定变速风力涡轮机系统的实际跟踪控制问题. 与现有文献对系统不确定性和参考信号的严格限制(系统参数已知, 扰动光滑或上界已知, 参考信号二阶可导)不同, 本文允许系统参数全部未知, 扰动不必可导且上界不必已知, 参考信号仅需一阶可导, 因此传统控制设计方法无效. 为此, 本文首先给出误差系统, 将原系统的跟踪控制问题转化为误差系统的镇定控制问题. 然后, 对误差系统选择适当的李雅普诺夫函数, 将自适应动态补偿技术融入反推控制设计框架, 给出自适应状态反馈控制器显示形式. 性能分析表明该控制器保证闭环系统所有信号有界且转子转速实际跟踪到期望转速, 即在某个时刻之后到达并保持在期望转速的任意给定邻域内. 值得指出的是, 所设计的控制器仅依赖于参考信号本身而不依赖其导数, 因此降低了相关文献对参考信号可量测性的限制. 最后, 仿真实验验证理论结果的有效性.

Practical tracking control for a class of uncertain variable speed wind turbine systems

Practical tracking control for a class of uncertain variable speed wind turbine (VSWT) systems is investigated in this paper. Different from the existing literature where strict constraints are imposed on the system uncertainties and reference signals (e.g., system parameters must be known, disturbance must be smooth or has known upper bound, and moreover, the reference signal must be twice differentiable), in this paper, all the system parameters are unknown, the disturbances are not necessarily differentiable or have known upper bounds while the reference signals are only first-order differentiable, and hence those result into the ineffectiveness of the traditional control methods. For this, an error system is derived firstly whose stabilization implies the tracking of the original system. Then, by choosing appropriate Lyapunov functions for the error system, adaptive dynamic compensation technique is incorporated into the back stepping control framework, and an adaptive state feedback controller is explicitly constructed which ensures that all signals of the closedloop system are bounded while the rotor speed practically tracks the desired one, i.e., the rotor speed arrives at and then stay within an arbitrary neighborhood of the desired speed after some time. It is worth pointing out that the designed controller only depends on the reference signal itself but regardless of its derivative, and hence relaxes the restrictions on the measurability of the reference signal in the related literature. Finally, a simulation example is provided to verify the effectiveness of the proposed theoretical results.