Application Of Adaptive Genetic Algorithm In Decoupling Control Of Variable Air Volume Air-conditioning System

With the rapid development of science and technology,people's living standard has been greatly improved,and higher requirements have been put forward for the comfort of living and working environment.The central air conditioning system is widely used in modern buildings.Although the traditional air conditioning system can meet the requirements of comfort,the energy consumption is huge.Vav systems have received wide attention due to their advantages of energy saving,flexible control and low energy consumption.The control parameters of vav system directly affect its control performance,and then affect the operation state and energy saving efficiency of the air conditioning system.Therefore,it is of great significance to optimize the performance and save energy of the air-conditioning system to study the appropriate control method.At the same time,vav system is characterized by multiple variables,nonlinearity and strong coupling,so it is difficult for traditional control methods to obtain a good control effect,which also hindering the development of vav system to some extent.Aiming at the characteristics of vav system and the problem that the traditional control algorithm is difficult to control effectively,the adaptive genetic algorithm is applied to the actual control process of vav system.Genetic algorithm(GA)is a global optimization algorithm that simulates the natural selection in Darwin's theory of biological evolution and the computational model in genetics to find the optimal solution.This paper introduces the basic content of genetic algorithm and analyzes the defects of genetic algorithm.Aiming at the defects of genetic algorithm,adaptive genetic algorithm is adopted to make up for them,which is mainly improved from four aspects: population analysis,individual fitness value scaling method,adaptive adjustment of crossover probability and mutation probability,and retention of excellent individuals,so as to improve the operation efficiency and convergence speed of the algorithm.Adopts the basic genetic algorithm and adaptive genetic algorithm for PID controller parameters optimization,respectively,for the secondorder system,nonlinear system and the lag of the second order system simulation analysis,the simulation results show that the PID controller based on adaptive genetic algorithm has better dynamic characteristics and control effect,to verify the validity and reliability of the algorithm.By analyzing the working principle of vav air conditioning system and combining with system identification,the transfer function matrix of the controlled object is obtained.On this basis,the PID controller of each control loop is designed,and the parameters of the PID controller are adjusted with the adaptive genetic algorithm.Finally,the adaptive genetic algorithm PID controller and the basic genetic algorithm PID controller are used to decouple the three control loops of VAVBOX air conditioning system,namely,the chilled water flow-air supply temperature,the VAVBOX air valve opening-room temperature,and the fan frequency-air duct static pressure.Then the three coupling loops were simulated on the Matlab/Simulink platform,and finally the Labview+Matlab program was written and loaded onto the vav experimental platform for experiments.The simulation and experimental results show that the efficiency and accuracy of the adaptive genetic algorithm in searching for optimization problems are greatly improved compared with the traditional genetic algorithm,and the overshot and adjustment time of the system are reduced.At the same time,the adaptive genetic algorithm has strong anti-interference and robustness.