分布参数系统的顺流型热交换器的渐近近似法与预测控制Smith法补偿

分布参数系统由于是偏微分方程描述,具有无限维的特性。在极大多数情况下,无法求到它的精确解,而且求解也相当繁复。因此不少研究分布参数系统的科学工作者对这方程式近似方法进行了大量的研究,如差分法,特性曲线法和MWR法等;或者把分布参数系统近似成集中参数系统,或者把高价方程简化为低阶方程等。在此基础上再进行系统设计,加以补偿,以得到良好的系统特性。本文以典型的顺流型热交换器为例,介绍此类分布参数系统的另一种渐近近似法,并在此基础上用预测控制Smith 法进行补偿,给出计算机仿真结果,从根据轨迹角度来探讨补偿结果

An Asymptotic Approximate Method of the Parallel-flow Heating Exchanger with Distributed Parameters and a Compensation of the System Using Smith Predictive Control

A distributed parameter system,which possesses a character of infiniteto dimension,is described by partial differential equations.Under mostconditions,it is difficult to find its exact solution and is time consumingsolve such a problem.Therefore scientists have been engaged in research onapproximate solutions of the partial differential equations,e.g.,the differencemethods,the methods of characteristic curve and MWR method etc.,i.e.,by using approximate lumped parameter systems or simplifying the highorder equations to lower order equations and then by system designing andcompensating to improve its performance.In this paper,with the parallel-flow heating exchanger as an example,anew asymptotic approximate method is presented.In this method,we use thewell-known Smith predictive control to compensate the system and study theeffect of the compensation by root locus method,and simulation results are given.