锅炉主蒸汽温度控制系统二次优化控制研究

锅炉主蒸汽温度关系到电厂的安全性和经济性,而主蒸汽温度控制具有大滞后、大惯性、扰动因素多的特点,常用的串级控制很难保证控制精度和稳定性。针对这类被控对象,进行了常规控制系统的分析,提出运用二次优化原理进行控制系统设计,并在控制系统中引入预估模型实现二次优化控制,最后增加非线性均方根放大器环节对优化控制系统再优化。以电厂锅炉主蒸汽温度控制系统为例,对二次优化控制进行了仿真研究,并与传统PID控制进行比较。结果表明,该方法显著提高了控制系统的动态特性、稳态精度及鲁棒性,实现了无超调量、无稳态误差的控制精度。

Research of Twice Optimum Control for Boiler Main Steam Temperature Control Systems

Boiler main steam temperature is an important factor that affects the safety and economy of the power plant. However, the temperature control has the characteristics of great inertial, long time-delay and time varying, so common cascade control method is difficult to guarantee the control precision and stability. For this kind of controlled object, the theory of twice optimum is applied to design of control system by analyzing the general control system. To realize twice optimum control, a forecast model is introduced in this paper. Next, cascading a non-linear square-root amplifier to improve control effect is suggested. Take boiler main steam temperature control system of power plant for example, twice optimum control is studied by simulation and compared to PID control. Results show that the method has significantly improved the dynamic property, the steady accuracy, and the robustness of this kind of control system. The overshoot and the steady-state error of the control system is zero.