Research On Data Driven Control Scheme Of Absorption Lithium Bromide Air Conditioning System

This paper applies the data-driven control scheme to the control problem of absorption lithium bromide air-conditioning system.Aiming at the characteristics of lithium bromide air-conditioning system,such as large lag,nonlinearity,and difficulty in establishing accurate models,an improved data drive control scheme was proposed,and TRNSYS software and MATLAB simulation platform were established for experimental research,which verified the effectiveness of the new algorithm.The main research contents and results are as follows:First of all,in order to make the lithium bromide unit control scheme more flexible and better track the set-point temperature,this paper is based on the basic model-free adaptive control(MFAC: Model-free adaptive control)algorithm.For the two parameter constraint terms of fixed ratio,an important parameter constraint term in the input criterion is selected with a fixed variable proportion and its rate of change in the control input criterion function.An improved MFAC control algorithm is derived to control complex lag air-conditioning systems.At the same time,the scheme is applied to the lithium bromide refrigeration system.Simulation results show that the new control algorithm has superior control performance.Secondly,in order to solve the control problem of the refrigeration system with time-delay characteristics,this paper proposes a parameter estimation control scheme that introduces two parameters L1,L2,and improves the pseudo-bias derivative parameter estimation process of the model-free adaptive predictive control algorithm(MFAPC).Then,the control output error is added to the control input criterion function,and an improved model-free adaptive predictive control algorithm is derived.The improved model-free adaptive prediction algorithm is applied to the refrigeration system control scheme.The simulation results show that the improved model-free predictive control algorithm can achieve more stable output and solve the control problem of refrigeration system with time-delay characteristics.Then,for the large changes in the working conditions of complex refrigeration systems,strong non-linearity and the problem of time delay,this paper proposes an improved data-driven control method based on synchronous perturbation stochastic approximation(SPSA)The controller part and parameter estimation process of the stochastic approximation control algorithm for synchronous disturbances are improved.An improved SPSA-based data-driven control algorithm is applied to the refrigeration system.Simulation results show that the algorithm can achieve relatively ideal control results.Finally,in order to establish an accurate model to study the control effect of the improved algorithm on the actual system,this paper uses TRNSYS software to establish the TRNSYS and MATLAB co-simulation platform to build the actual system model.Then,the improved model-free adaptive algorithm,improved model-free adaptive predictive control algorithm and improved data-driven algorithm based on synchronous perturbation stochastic approximation are simulated on the dynamic simulation platform to verify the effectiveness of the new control algorithm.