| Plate heat exchangers,due to their small footprint and high heat transfer efficiency,are widely used in industrial production and civil heating fields in China.They are commonly used equipment in heat exchange,and the outlet temperature is achieved by the heat exchange of cold and hot fluids.With the expansion of the application scope of heat exchangers,people’s requirements for their temperature control stability,hysteresis resistance,and anti-interference ability are also increasing.This article starts from four aspects: analyzing and modeling the heat exchange principle of plate heat exchangers,designing decoupling controllers that are coupled and decoupled with each other,improving the anti-interference performance of the system with an autodisturbance rejection controller,and intelligent optimization of the parameters of the auto-disturbance rejection controller.The decoupling controller is designed by coupling the two branches of quality regulation and quantity regulation to achieve state feedback,The method of precise temperature adjustment by the self-disturbance rejection controller to improve the performance of the plate heat exchanger system.Firstly,based on the study of the heat exchange principle and structure of plate heat exchangers,this article takes the modeling of heat exchanger temperature control as the research object to study the characteristics of strong coupling,strong hysteresis,and disturbance instability during the control process of plate heat exchangers.By adjusting the opening of the primary side outlet valve and the frequency of the secondary side circulating pump,the control optimization of the secondary side temperature is achieved,The Gauss Newton’s method is used for system identification of the model,and the proposed recursive algorithm is easy to implement in industrial production conditions due to its simple operation steps.Second,in order to make up for the disadvantage of strong coupling in the temperature control of plate heat exchanger,this paper analyzes the coupling characteristics of the control object and designs a decoupling controller.To comprehensively test the decoupling performance of the control object,compare the response time and decoupling degree with traditional cross decoupling and feedforward decoupling devices.The simulation experiment results show that the decoupling controller based on state feedback has the shortest adjustment time and the best decoupling degree.Thirdly,based on the temperature control characteristics of the plate heat exchanger,such as time-varying,hysteresis,and susceptibility to interference,an Active Disturbance Rejection Controller(ADRC)is used to suppress external interference,and genetic algorithm is used to optimize its parameters.The tracking performance and system stability of the established extended state observer(ESO)are analyzed.By adjusting the nonlinear state error feedback control law coefficient in ADRC,the stability of the system under bounded input conditions is achieved.To verify the working performance of the self disturbance rejection controller,experimental comparison and analysis were conducted with traditional PID control,adaptive fuzzy PID and other control methods.The results showed that the self disturbance rejection controller had the shortest adjustment time,the fastest response time,and the strongest anti lag performance.Fourthly,the superiority of the control algorithm is verified through temperature control simulation experiments on plate heat exchangers.The simulation results show that the genetic algorithm optimized parameter controller based on state feedback decoupling can achieve complete decoupling of temperature control,ESO has good tracking performance,the controller has better anti-interference performance,response speed and time delay resistance have been greatly improved,ensuring efficient and stable operation of heat exchange stations.This algorithm has great practical application value in practical engineering. |
