Controller Design And Control System Simulation Of The Vapor Compression Refrigeration System

Vapor compression refrigeration system(VCRS)has a wide range of applications in people’s production and life,but also consumes a lot of pow er resources,and its operating efficiency needs to be improved urgently.However,the variables of VCRS are not only strongly coupled and non-linear but also subject to several constraints.It is difficult for traditional controllers to ensure their effic ient operation.Model predictive control(MPC)can make up for the shortcomings of traditional controllers.Its design process includes the establishment of dynamic models,the identification of dynamic model parameters and the design of optimization algor ithms.This paper has carried out the following research work in these three aspects: first the dynamic model of VCRS was established,and the order reduction and linearization of each component model in VCRS were completed.Compared with the response of actual VCRS,it was found that this model can not only describe the main characteristics of VCRS,but also have high calculation accuracy.Then,the VCRS steady-state model is established,and the model is used to solve most of the steady-state operating parameters of the system under different working conditions,thereby reducing the number of parameters to be identified and the difficulty of parameter identification.Finally,a model predictive controller is designed for VCRS.The Hildreth method and Laguerre network method are used to optimize the solution process of the optimization algorithm in MPC,thereby greatly reducing the time consumption of calculating the optimal control action process.On the MATLAB platform,computer simulation results show tha t even in the case of constraints,disturbances,and parameter perturbations,the MPC system can still ensure that the output of VCRS tracks the set value quickly and accurately.From the research results,the VCRS dynamic model and steady-state model established in this paper provide a high-precision prediction model for MPC.The MPC algorithm designed for VCRS in this paper provides a reference for the application of MPC in VCRS and has certain engineering application value.