汽轮机电液伺服系统建模及控制方法

Modeling and control method of electro-hydraulic servo system for steam turbine

汽轮机电液伺服系统液压油的油液密度、体积弹性模量等参数随环境温度、压力等条件变化而变化,且系统存在未建模动态,致使电液伺服系统难以获得良好的跟随性。本文以200 MW中间再热凝汽式汽轮机电液伺服系统为研究对象,根据力平衡及流量连续性原则,建立了双侧进油油动机数学模型。通过仿真分析了油液密度、体积弹性模量变化对系统性能的影响,在此基础上设计了滑模变结构控制器,并采用指数趋近律设计方法来削弱滑模变结构控制中的抖振问题。通过MATLAB仿真平台,对所设计的控制系统进行仿真验证,并与经参数优化后的PID控制系统进行仿真对比。结果表明:本文所设计的控制器具有良好的跟踪性和对不确定性参数、外负载干扰的适应能力。

The oil density and volume elastic modulus of hydraulic fluid of the electro-hydraulic servo system in steam turbine change with the ambient temperature and pressure, and the system has unmodeled dynamic, which makes it difficult for the electro-hydraulic servo system to achieve a good tracking ability. Taking the electro- hydraulic servo system in a 200 MW intermediate reheat condensing steam turbine as the research object, this paper established a mathematical model for bilateral oil motive, according to the principle of force balance and flow continuity. The influence of oil density and volume elastic modulus on the system performance was analyzed by simulation. On this basis, a sliding mode variable structure controller was designed, and the exponential convergence law design method was used to weaken the chattering problem in sliding mode variable structure control. The simulation system of the designed control system was simulated and verified by Matlab simulation platform, and compared with the PID control system with optimized parameter. The results show that, the controller designed in this paper has good tracking ability and adaptability to uncertain parameters and external load interference.