| The rapid development of the auto industry has driven the rapid growth of fossil energy consumption and pollutant emissions,and the task of energy conservation and emission reduction is arduous.As an efficient and clean hydrogen-to-electricity energy conversion device,proton exchange membrane fuel cell（PEMFC）has the characteristics of fast startup,high reliability,no pollution and efficient,and has been increasingly applied in the new energy vehicle industry.Aiming at the problem of comprehensive performance evaluation of fuel cell power system under vehicle operating conditions,this thesis from the perspective of fuel cell system integration,considers the energy consumption of system accessories and other factors,establishes a vehicle proton exchange membrane fuel cell system model,and studies the dynamic engineering.The energy consumption of auxiliary equipment is analyzed under the condition of energy consumption,and the mapping relationship between operating parameters and the efficiency of the system is analyzed,and the economical and environmental performance of the power system is comprehensively evaluated.It provides a new research idea for the research of vehicle PEMFC system.The specific work is as follows:First,the model of the vehicle proton exchange membrane fuel cell system is established.The system includes PEMFC stack,hydrogen circulation pump,air compressor,cooling water pump,humidifier,etc.Explore the energy consumption of auxiliary equipment of fuel cell system（air compressor,hydrogen circulation pump,cooling water pump,humidifier）and its mapping relationship with the performance of fuel cell system,and analyze the electrical loss and thermal loss of auxiliary equipment under dynamic conditions.Secondly,the thermodynamic performance of the vehicle fuel cell system under dynamic conditions is analyzed.The electrical and thermal losses of the auxiliary equipment and the output power and system efficiency of the fuel cell power system under dynamic conditions were calculated,and the effects of operating parameters such as system temperature and humidity on the thermodynamic performance of the system were obtained.The results indicate that the air compressor has the highest energy consumption and the humidifier has the lowest energy consumption;high intake air humidity and high operating temperature help to simultaneously improve the net power output and electrical efficiency of the PEMFC system.The thermodynamic performance of the system is best under the operating conditions of a stable operating temperature of 358K,cathode and anode air inlets,and 100%humidity.The maximum electrical power reaches22.5k W,and the maximum electrical efficiency and thermal efficiency reach 46.5%and 52.2%,respectively.Finally,the economic and environmental evaluation model of the vehicle PEMFC system is established,and the change of hydrogen consumption under the operation of the PEMFC system is analyzed.Taking the total system cost and the emission quality of polluting gases in the hydrogen production process as the evaluation indicators of economy and environment,the system economy and environment were evaluated from the perspectives of transient response and long-term operation.The results show that increasing the operating current will lead to an increase in the intake air volume of the system and an increase in the power of the cooling system,which increases the operating cost of the system.When the current is stepped from 230A to 300A,the difference in total system cost is 1646$.After the system runs for 2400h,the total system cost is 62616$.The increase in current will lead to an increase in hydrogen consumption and an increase in the emission of hydrogen pollutants.Under the current fluctuation of 600s,the maximum hydrogen consumption of the system reaches 6.4×10-4kg.Among the three methods of hydrogen production,the quality of pollutant emissions produced by wind energy is the lowest,and the maximum transient emissions of NOx,CO,GHG and VOC in the process of hydrogen production are 1.52×10-3g,1.28×10-3g,1.85g,1.19×10-4g,respectively.The greater the power of the PEMFC system,the greater the hydrogen consumption during its operation and the greater the emission of pollutants. |
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