Decoupling Control Strategy Of Temperature And Humidity In VAV Air Conditioning System

With the progress of modernization and the continuous improvement of people’s quality of life,people are looking for a more comfortable building life and production environment.As an important equipment in modern intelligent buildings,air conditioning system has been widely used in human production and life.At this stage,air conditioning system not only need to meet the indoor comfort,but also need to reduce energy consumption.However,due to the shortage of control mechanisms,constant air volume air conditioning systems are usually difficult to meet these requirements at the same time.VAV air conditioning system can make the temperature of the room meet people’s needs only by adjusting the air volume sent into the room,thereby greatly improving the efficiency of the equipment,and can realize the energy saving of the air-conditioning system.Therefore,the variable air volume air-conditioning system is currently a highly flexible and energy-saving system,and it is the development and research trend of air-conditioning systems in modern buildings.Although the variable air volume air conditioning system has the advantages of high comfort and high energy saving efficiency,it also has many variable factors that make it unable to work smoothly.When all the loops in the system work at the same time,it will cause the disadvantages of poor coordination and stability between the loops,and waste of energy.In order to solve the problem of coupling and instability between the temperature and humidity loops of the variable air volume air conditioning system,a variety of decoupling control strategies are proposed in the article to improve the control quality of the variable air volume air conditioning system to meet the temperature and humidity control requirements.In this paper,the coupling problem of temperature and humidity in VAV air conditioning system is studied.The following aspects are mainly completed:(1)In this paper,the principle,composition and characteristics of VAV system are introduced in detail,and the coupling characteristics of temperature and humidity of VAV system are explained,which lays a theoretical foundation for the study of temperature and humidity decoupling of VAV system.(2)In order to eliminate the mutual interference between the temperature and humidity of the air-conditioning system,the feedforward compensation decoupling is designed according to the principle of invariance,and the fuzzy PI~λD~μcontrol is proposed to further optimize the decoupling control loop.(3)Because of the strong dynamic coupling which cannot be eliminated by static decoupling,the reverse decoupling of dynamic decoupling is used to eliminate the coupling between temperature and humidity.The traditional fireworks algorithm is improved to find the optimal filter parameters of internal model PID control.Finally,it is applied to the decoupled temperature and humidity control system and verified by simulation.(4)A multivariable internal mode decoupling control strategy with both a decoupler and a controller was proposed,and the optimized Butterworth filter replaces the traditional first-order filter to make the control system have better dynamic and steady state characteristics.Then the immune genetic algorithm is used to reduce the order of the controlled object model,which makes the system structure simple and easy to calculate.Finally,the improved multivariable internal model decoupling control is compared with the traditional PID control.