1000MW超超临界机组汽温多模型预测控制研究

针对电厂过热汽温对象大惯性、大滞后及参数随负荷变化显著的特点,利用非线性过程(线性不确定过程)在多个工作点上的线性化模型,把整个对象工作空间划分为若干子空间,而每个子空间可以找到一个较精确的固定模型,再通过加权子模型获得复杂对象的全局近似模型作为预测模型,然后采用线性优化或非线性优化方法计算预测控制器输出进行汽温控制,并给出具体的现场应用实施方案。实际仿真和应用结果证明无论对于稳态过程或负荷变化过程,过热汽温都能维持在要求的控制范围内,能够有效保证机组的安全经济运行。

Study on Multi-model Prediction Control on Steam Temperature of 1 000 MW Ultra-supercritical Unit

Aiming at characteristics of great inertial and large lag of overheat steam temperature object and obvious change of parameters with change of load, this paper uses linear model on multiple work points of nonlinear process which means uncertain linear process to divide the whole object work space into some subspaces and each subspace is able to find an accurate fixed model. By weighting sub-model, it is able to get an overall situation approximate model of the object as prediction model and by using linear optimization or nonlinear optimization, it is able to work out output of prediction controller for steam temperature control and providing definite field application and implementation scheme. Practical simulation and application result prove that no matter in process of steady-state or load change, it is able to keep overheat steam temperature in required control range and effectively ensure safe and economic operation of the unit.