Adaptive Robust Control for the Steam Temperature of Thermal Power Plant in Sliding Pressure Operation

采用模块化建模系统MMS（Modular Modeling System）开发了火电厂滑压运行仿真系统。MMS提供了大量的模块，这些模块是基于热力学定律开发的。本仿真系统采用了锅炉、过热器、减温器、涡轮机、省煤器、管道、凝汽器、减温器、给水加热器等200多个MMS模块，并结合真实的电厂和制造厂的数据，对开发的仿真系统的准确性进行了验证。仿真结果表明，在额定负荷下的仿真结果与真实的电厂的仿真结果吻合较好。通过仿真算例表明，该模拟器是稳定的，但在计算方面还存在一些问题。模拟器在计算中是“僵硬的”，因为有非常快的模式和非常慢的模式。快模态起源于涡轮机， ...更多信息 w模式源自锅炉和再热器。当负载需求变化较大时，仿真需要耗费大量的CPU时间.由于计算刚度的限制，使得仿真台的动态精度难以验证.在研究了真实的电厂现有的PI控制系统的基础上，提出了一种新的控制系统结构，即由主蒸汽压力和负荷的要求到燃料流量控制系统和主蒸汽温度控制系统的FF（前馈）控制作用。所提出的FF控制可以插入到当前基于PI的控制系统中。为了设计FF控制器，建立了锅炉对象的时变模型。该模型由锅炉装置在多个负荷和压力需求水平下的多个线性模型插值而成。这些线性化的模型通过用伪随机二进制序列（PRBS）激励模拟器来识别。根据该时变模型，设计了一种根据负荷和压力要求进行增益调度的FF控制器。针对负荷和压力需求的小阶跃变化和负荷和压力需求的大斜坡变化的情况进行了大量的仿真研究。仿真结果令人满意。主汽温的控制误差比无FF控制器时减小了50%。少

A simulator has been developed for the purpose of studying of the sliding pressure operation method for thermal power plants by means of MMS (Modular Modeling System). There are a lot of modules supplied by MMS,which are developed based on the laws of thermodynamics. These modules are boiler, superheater, attemperator, turbine, economizer, piper, condenser, deaerator, feedwater heater, and so on. Two hundreds of MMS modules are used to develop the simulator together with the data collected from real plant and manufactory.Several studies have been done in order to validate the accuracy of the developed simulator. It is shown that the results of the simulator at the rated load are agreed with that of the real plant well. Although the simulator is ahown to be stable by simulation examples, there still exist some problems in calculation aspects. The simulator is 'stiff' in calculation, because there are very fast modes and very slow modes. The fast modes originate from the turbine, and slo … More w modes originate from the boiler and reheater. The simulation costs amount of CPU time if demand of load is changed largely. The calculating stiffness makes it difficult for us to validate the dynamic accuracy of the simulator. A simlified simulator has then been developed in order to improve the calculating efficiency.After studying the current PI based control systems of the real plant, we have developed a new control system structure which is composed of a FF (feedforward) control action from the demands of load and pressure of main steam to fuel flow rate control system and temperature control of main steam. The proposed FF control can be plugged in the current PI based control systems. In order to design the FF controller, a time varying model for boiler plant is developed. This model is interpolated by several linearized models of the boiler plant at several levels of demand of load and pressure. These linearized models are identified by stimulating the simulator with PRBS (pseudo random binary sequence). According to this time varying model, a FF controller that is gain scheduled by demands of load and pressure is developed. A lot of simulation studies have been carried out for cases of small step change of demand of load and pressure and large ramp change of demand of load and pressure. The simulation results are satisfactory. The controlled error of main steam temperature has been reduced to 50% comparing with that of without FF controller. Less