Control Configuration Design Of Process Complex Control System And Block Decentralized Control System

With the development of the process industry,more and more non-square multivariable systems and high-dimensional large-scale systems appear in chemical process.The common method of dealing with non-square multivariable system is increasing or decreasing several inputs or outputs to make it square,but this method does not make full use of all the measurable variables and ignores some inner interactions,thus,the control requirements is unable to be satisfied.Now,the full decentralized control strategy or the centralized control strategy is adopted to deal with high-dimensional large-scale systems.But there usually are complex interactions in high-dimensional large-scale systems,it's always hard for the decentralized control strategy to get good performance and also hard to design and achieve the centralized control strategy.This paper propose some new control configuration design methods to solve these problems.Firstly,based on Relative Gain Array(RGA),the non-square RGA(NRGA)is introduced then extended to frequency domain,so the average frequency NRGA is deduced.Based on the average frequency NRGA,a new complex control system designing method of non-square systems is proposed.The cascade control strategy is used to thin systems and the feedforward-feedback control strategy is used to fat systems.Both of the two control strategies take all the measurable variables into account,so they are more effective for control performance.Secondly,the primary controlled variable,the secondary controlled variable,the adjustable operating variable and the non-adjustable operating variable are defined for large-scale systems.According to these definitions,a large-scale system is divided into several subsystems and the control configuration design is implemented individually,and an integrated regular control system designing method is put forward involving single loop control,cascade control and feedforward-feedback control.The cascade control system is used to dealing with the situation that two outputs pairing one input,and the feedforward-feedback control system is used to dealing with the situation that two inputs pairing one output.Finally,two kinds of block decentralized control configuration design methods are provided for large-scale systems.The first method is to select several closed-loop properties of block relative gain,and these properties will be used as the screening conditions of system decomposition structures,then,the block pairing rules of inputs and outputs are used to find all the possible decomposition structure which satisfying screening conditions.In the second method,a flexible comprehensive evaluation criterion for large-scale systems structural decomposition is formed based on the conception of simplicity and controllability.According to this criterion,an efficient method to screen the possible decomposition structure of large-scale systems is proposed to select the most reasonable block decentralized control configuration design structure.