火电厂主汽压力的IMC-PI控制系统设计

针对电厂主汽压被控对象的大惯性、大滞后特点,采用炉膛辐射能作为中间被调量,构成了一种内模－比例积分串级控制系统。内回路采用比例积分控制,以快速消除燃料量引起的扰动;外回路采用内模控制,以有效地补偿对象的大滞后特性。采用具有纯滞后的一阶惯性环节作为广义被控对象的内部模型,给出了广义被控对象模型的建立方法及控制系统的设计步骤。对控制系统进行仿真试验,试验结果表明,所提出的控制方案有很好的克服扰动和给定值响应能力。

IMC-PI cascade control for main steam pressure system of power plant

Considering that main-steam pressure is a big-inertial and big-lagged object, the IMC-PI cascade control strategy is presented. It uses the furnace radiation signals as intermediate regulated variable. The inside loop is used to overcome fuel disturbance quickly, and the outside loop is used to compensate time-delay of object. The general controlled object including inside loop is modeled by first order lag plus time delay model. The process of model building is discussed in detail and the design approach of control system is given. It is shown through simulation tests that the proposed control system has good adaptability to overcome disturbances and track set point.