汽轮机数字电液控制系统（DEH）是电厂自动化控制系统重要的组成部分。DEH控制系统主要包括转速控制系统和负荷控制系统，由于负荷扰动、汽压扰动及其他外界干扰的影响，系统存在不稳定性，系统中再热器部分具有滞后现象，内部结构复杂，控制变量较多等因素，常规控制方式很难达到理想效果，控制品质需要进一步提升。模糊控制，是智能控制的一个分支，也是近年来控制界学者研究的热点，模糊控制具有仿人智能的特点，在大滞后、扰动、非线性等复杂控制系统中具有较好的动态控制效果。常规PID控制能消除系统的稳态误差，使系统具有较好的稳态特性。 本文将模糊控制与PID控制结合，在转速控制回路，利用模糊控制的模糊推理规则对PID参数进行整定，使PID参数能随着控制系统的变化而实时调整，可减少现场工作人员的工作量及操作误差，使系统得到更好的控制。在负荷控制回路，升负荷过程中，偏差变化较大，利用模糊控制及PID控制各自的优势，当偏差变化较大时采用模糊控制，响应速度快可抑制系统产生超调，小偏差时采用PID控制，有助于消除静差，防止干扰。由于DEH控制系统中被控对象较多且数学模型难以精确，运用MATLAB仿真实验平台建立模糊数学模型及采用模型优化方案对两种控制系统进行仿真实验。实验中，模糊控制与PID控制相互转换时切换开关存在扰动问题，在此引入信号跟踪的方法实现开关的无扰动切换。实验结果表明模型的建立及复合控制方案的引入较传统控制在快速、稳定等方面取得了较好的控制效果。此复合控制算法的仿真研究也可应用于具有类似结构的其他复杂控制系统。仿真实验对实际应用具有一定的指导作用。开关的无扰动切换方法可应用于类似的阀门管理等实际中。

Steam turbine digital electro-hydraulic control system(DEH)is an important part in automatic control system of power plant. DEH control system conclude the speed control system and load control system. The conventional control method is difficult to achieve the desired effect, and further enhance the quality control needs because of the complexity of the system internal structure, the numerous control variables and the load disturbance, the influence of the vapor pressure perturbations, and other external interference caused the system instability, the reheater portion also have a delayed phenomenon etc. Fuzzy control is a branch of intelligent control , but also it have been a hot research in recent years . The advantage feature of fuzzy control is humanoid intelligent, it has a good dynamic control in disturbance, nonlinear and complex control system . The conventional PID control can eliminate the steady-state error of the system, making the system have good steady state characteristics. Combinationing fuzzy control and PID control, for one sides，we can use fuzzy control rules to complete PID parameter tuning in the speed control loop, the PID parameters can be adjusted in real time with the change of the control system, it can reduce the workload of field staff and operator error, making the effect of control system to be better . Another，making use of fuzzy control and PID control ‘s advantages during load process deviation change greater in Load control circuit, using fuzzy control when large deviation change, it can make fast response and inhibit overshoot, using PID control when small deviation, it could help eliminate static error and prevent interference. The mathematical model is difficult to be accurately established because of multi- controlled objects in DEH control system. So make use of fuzzy mathematical model and model optimization have simulation experiments in the two control systems through MATLAB simulation platform. Existing switch disturbance problem when fuzzy control and PID control conversion during experiment processing .The paper introduced switching signal tracking method . The experimental results show that the introduction of the model and composite control scheme achieved better control effect in fast and stable compared with the traditional control. The simulation of the composite control algorithm may also be applied to other complex control system with a similar structure. The simulation experiments play a guidance on the practical application . Besides，the bumples transfer method can be applied to the similar valve management practice.