【作者】 王浩；

【导师】 闫伟；

【作者基本信息】 山东大学 ， 载运工具运用工程， 2019， 硕士

【摘要】 随全国乃至全球汽车保有量的上升,能源短缺、环境污染、排放严苛、战略导向等问题使不同国家纷纷将汽车发展方向转移到新能源汽车特别是纯电动汽车上,新能源汽车成为了下一步汽车工业的竞争重点和发展引擎。本文主要设计基于智能算法的整车热管理系统,使动力系工作在适合的温度以提高电机效率,也为在低环境温度下加热动力电池、在高环境温度下冷却动力电池包,保证行驶可靠性的同时,减少能量消耗,增加续航里程。本文基于某品牌纯电动汽车整车热管理开发,首先通过试验方式得到锂动力电池单体在不同温度和不同充放电倍率下的性能表现和温度变化情况,根据试验数据拟合出动力电池单体物性参数和欧姆内阻关于温度和SOC的函数表达式,进而得出生热速率公式,基于生热速率公式通过UDF赋值热源的方法进行CFD仿真得到不同倍率下的温升计算结果,对比试验数据验证生热速率公式。然后根据整车参数对热管理系统中重要部件进行参数匹配,设计整车热管理方案,在一维仿真软件中搭建电机部分和考虑空调制冷的电池包冷却模型,得到不同行驶工况下的电机出水温度和电池包进水温度,对比整车风洞试验数据验证仿真模型,并仿真得到不同因素的变化对热管理系统性能的影响,得到对系统制冷能力影响较大的变量,确定下一步智能算法控制对象为电子风扇和电动压缩机。最后通过一维仿真模型得到不同工况下符合温度要求的电子风扇和电动压缩机转速,生成电子风扇和电动压缩机转速的样本数据,运用回归型的SVM智能算法(SVR)对两样本数据库进行训练预测,验证SVR模型的预测准确性。将SVR模型嵌入到一维仿真软件中,联合运行NEDC工况,得到基于SVR控制的电机出水温度和电池包进水温度的变化情况,与阈值控制的仿真结果进行对比,结果得出基于SVR控制的热管理系统能在满足温度要求的基础上,使电子风扇和电动压缩机在较低的转速范围内运行,可以减少电子风扇和电动压缩机的功耗,具有良好可行性。更多还原

【Abstract】 With the increase of car ownership in the whole country and even in the world,the problems of energy shortage,environmental pollution,emission stringency,strategic orientation and so on have caused different countries to shift the direction of automobile development to new energy vehicles,especially pure electric vehicles.New energy vehicles have become the next competitive focus and development engine of the automobile industry.This paper mainly designs a vehicle thermal management system based on intelligent algorithm,which can make the power system work at the appropriate temperature to improve motor efficiency.It also can heat the power battery at low ambient temperature and cool the power battery pack at high ambient temperature to ensure driving reliability,reduce energy consumption and increase endurance mileage.Firstly,Based on the thermal management development of a brand pure electric vehicle,the performance and temperature variation of lithium power battery monomer at different temperatures and charge-discharge ratios are obtained through the test method.According to the test data,the physical parameters of power battery monomer and the functional expressions of ohmic internal resistance on temperature and SOC are fitted,and then the heat generation rate formula is obtained based on the heat generation rate formula.The rate formula is simulated by CFD with UDF heat source assignment method to get the temperature rise calculation results at different rates.The heat generation rate formula is verified by comparing the experimental data.Then,according to the parameters of the whole vehicle,the paper matches the important parts of the thermal management system,designs the thermal management scheme of the whole vehicle and builds the cooling model of the motor part and the battery pack considering air conditioning refrigerationt in one-dimensional CFD software.The outlet temperature of the motor and the inlet temperature of the battery pack under different driving conditions are obtained.The simulation model is validated by comparing the wind tunnel test data of the whole vehicle,and the influence of element change on the performance of heat management system is validated and determined.The next step is to determine the control objects of intelligent algorithm,electronic fan and electric compressor.Finally,with a one-dimensional CFD model,the paper obtains the reasonable rotational speed of the electronic fan and the electric compressor under different operating conditions and generates the sample data of the rotational speed of the electronic fan and the electric compressor.The regressive SVM intelligent algorithm(SVR)is used to train and predict the two sample databases to verify the predictive accuracy of the SVR model.Embedding the SVR model in the one-dimensional CFD simulation software,operating the NEDC condition,the paper obtains the change of the outlet water temperature and the inlet water temperature of the battery pack controlled by SVR.After compared with the simulation results of threshold control,the result shows that the heat management system based on SVR control can reduce the power consumption of the electronic fan and the electric compressor on the basis of meeting the temperature requirements,which has good feasibility.更多还原