汽轮发电机组轴系扭振的鲁棒非线性控制

提出将同步发电机及其励磁系统看做扭振励磁控制的执行元件,采用直接反馈线性化方法补偿其非线性因素,避免小偏差线性化模型的参数摄动问题,从而提高扭振励磁控制系统的鲁棒性.综合H∞扭振模态观测器、独立模态空间鲁棒控制器和非线性反馈补偿律,提出一种轴系扭振的鲁棒非线性控制策略,在大范围工况下具有一致的全局性能,并且3个组成部分可以分别独立设计;另外,可以方便地与常规非线性励磁控制律综合在一起,而不影响后者阻尼低频振荡的性能.以一台300 MW汽轮发电机组第1阶扭振模态的阻尼控制为例,通过仿真验证鲁棒非线性控制器的性能优于常规线性控制器.

ROBUST NONLINEAR CONTROL OF SHAFT TORSIONAL OSCILLATION OF THE TURBINE-GENERATOR

By considering the synchronous machine and excitation system as the actuator of torsional excitation control, it is suggested to use direct feedback linearization to compensate nonlinear characteristics of the actuator to avoid model parameter perturbation caused by deviation linearization and improve the robustness of torsional control system. A robust nonlinear control strategy of the shaft torsional oscillation is proposed by integrating the Hinfinity torsional modal observer with the independent modal space robust controller and the nonlinear feedback compensated law, which have consistent performance over wide range operating conditions. Above three components can then be designed respectively with little influence on each other. In addition, the proposed nonlinear strategy can be expediently integrated with the conventional nonlinear excitation control without affecting performance of the latter. A case study is given to validate the performance of damping control of the first torsional mode of one 300 MW turbine-generator unit. It is shown the robust nonlinear controller has better performance than that of the conventional linear controller.