Design Of VRV Terminal Controller Based On Embedded Technology

VRV air conditioning system is widely used in small and medium-sized commercial buildings and villas,it has the advantages of high comfort and controllability.Each room device can adjust independently,VRV air conditioning system can accurately meet the requirements of different rooms heat load.Due to the different indoor environment,air conditioning terminal devices has different demands for refrigerant,and refrigerant flow has an important influence to the air terminal device and the energy consumption of air conditioning system.The current environmental situation is not good,air conditioning energy conservation design has great significances.Aimed at the uncertainty of the indoor temperature control,in order to achieve the rapidity and accuracy of the indoor temperature control,this design to do the following work.This article first introduces the way that VRV air conditioning works,analyzes the VRV air conditioning terminal evaporator heat transfer principle.Room temperature control has non-linear,lag and coupling characteristics.Terminal controller controls the electronic expansion valve and refrigerant flow to affect the heat exchange.Fuzzy control dynamic effect is excellent,but the steady state control precision is poor,the fuzzy control is used in the terminal air-conditioning unit start control.When indoor temperature is close to the setting temperature,the system is switching to the PID control.Because PID initial parameter values cannot be changed according to the actual circumstances,thus introducing genetic optimization algorithm to optimize PID parameter values,making the room temperature control more accurate and avoiding vibration.Using Simulink simulation to verify the control effect of the design method.The next in the use of embedded technology to develop VRV terminal controller.Air terminal controller using STM32 processor as the main control chip,using uCOSII operating system as a controller platform,using LCD touch screen to set temperature and display temperature.The terminal embedded controller uses the control algorithm in the previous section,communicated with computer simulation model by serial port,verified the temperature control effect,proved that the controller can according to user needs to control room temperature,and improve the ability of temperature control.