Research On The Control Strategy Of Electric Vehicle Heat Pump Air Conditioner Based On The Technology Of Composite Defrost

As the global environmental pollution intensified and the lack of oil resources,the automotive industry is also looking for new impetus to protectect the environment.Because of the advantages of zero emission,low energy consumption and low noise,electric vehicles have been paid more and more attention.However,the battery is the only energy source of electric vehicles.The car system needs to have higher energy efficiency.Electric air-conditioning system is the second largest energy-consuming equipment in the electric vehicle in addition to the drive system.Unlike traditional fuel vehicles,electric vehicles do not have the engine cooling water.Its heating efficiency will directly affect the driving range and vehicle performance.Therefore,optimizing the heat pump air conditioning system,reduceing energy consumption and improving the heating efficiency are of great practical significance.An electric bus air conditioning system is taken as the research object.The air-conditioning drive program is established,and the parameters is matched,such as electric compressors,heat exchangers,fans and four-way valve.Defrosting is an important part of heat pump air composite conditioning heating process.Aiming at the deficiency of the existing defrosting method,the defrosting scheme was proposed,the defrosting logic was analyzed,and its advantages are verified by experiments.The traditional switching control method of electric air conditioning system is optimized.The optimization of traditional switch controlling algorithm is composed of putting forward a composite controlling method utilizing both fuzzy and PID theory to realize the frequency conversion control.At the same time,variable air volume control is used instead of traditional constant air volume control.The thermal load model,compressor model,heat exchange model,temperature calculation model and controller model are established in MATLAB / Simulink.Fuzzy-PID,fuzzy control,PID control and traditional switching control are simulated and compared to demonstrate the advantages of the proposed control method.Finally,with the help of an air conditioning laboratory of a factory,experimental platform is build.The LABVIEW software was finished.The data collected in the database are fitted in MATLAB.Through the data analysis shows that the simulation model is accurate,the composite defrosting method,fuzzy-PID control method and variable air volume control are useful to optimize the energy consumption of the electric vehicle heat pump air conditioning.It has important significance to improve the electric car mileage.