Study On Heating Conditions Of Pure Electric Vehicle Heat Pump Air Conditioning System Based On Fuzzy Control

The present widely used in pure electric vehicles PTC heating and air conditioning,this kind of heating way has the defects of low efficiency,high energy consumption.Heat pump air conditioning has been proved to be efficient and energy-saving in the field of home air conditioning.In this paper,the control strategy of heat pump air conditioning system applied in electric vehicle is studied.The main research contents include: theoretical research of heat pump air conditioning and model building and verification of model accuracy in AMESim software;Research on two-dimensional multi-output fuzzy control strategy for heat pump air conditioning;AMESim and Simulink co-simulation analysis;Software and hardware design of fuzzy controller based on STM32 microcontroller.In this paper,the definition of heat pump and the working principle of heat pump air conditioning system are briefly introduced.In addition,an electric vehicle heat pump air conditioning system model was built in AMESim software,referring to the experimental data collected on the heating conditions of the heat pump air conditioning system by professor wei mingshan’s team from the Beijing institute of technology.For-10℃,5℃ and 0℃ three groups of indoor and outdoor heat exchanger under the condition of import and export pressure,temperature has carried on the comparative analysis of the accuracy of the model was verified.Then,based on the instantaneous and nonlinear characteristics of the automotive air-conditioning system,a fuzzy control strategy with two dimensional multiple outputs is proposed.That is,according to the real-time temperature feedback in the car room,control the speed of the compressor and the speed of the indoor fan,adjust the amount of heat production,so as to achieve a high-precision regulation of the indoor temperature.The fuzzy control system was built in Simulink software and the heat pump air-conditioning model established in AMESim software was used for joint simulation.Research when winter outdoor environment temperature 0 ℃,humidity is 40%,the electric cars under the working condition of three kinds of speed,by looking at two dimensional multiple output fuzzy control strategy with the traditional control strategy(switch control strategy)under the two kinds of control strategies of the crew compartment temperature control effect(set temperature 18 ℃)showed that under the idle condition and common speed conditions,this paper design the control strategy,the crew compartment temperature can quickly reach the set temperature,and no overshoot phenomenon,after system stable accuracy within 0.1 ℃;Working condition of high speed,overshoot phenomenon appear within 0.5 ℃,this is due to the outdoor heat exchanger of air near the side of the air velocity faster speeds up the system so the heat exchange process.But temperature correction,quickly the last stable temperature near the 18 ℃,precision can reach 0.1 ℃;Compared with the traditional switch control strategy,the control strategy designed in this paper can quickly raise the temperature of the crew cabin to the target temperature,and the temperature control precision is more accurate,the callback time is shorter,and the comfort is better.Finally,based on the good results of simulation,the preliminary software and hardware design of the fuzzy controller is carried out with embedded single-chip STM32F103 as the core.The hardware of the fuzzy controller for heat pump air conditioning is trial-produced and debugged.