Design Of Control Strategies For Automotive Proton Exchange Membrane Fuel Cell Thermal Management System Under Variable Load Condition

China’s huge inventory of fuel vehicles is an important factor leading to energy crises and environmental issues.Hydrogen energy,with its high energy density,pollution-free,and carbon emissions free characteristics,is the best solution to energy and environmental issues.Proton Exchange Membrane Fuel Cell(PEMFC),with its high energy conversion rate and strong environmental adaptability,is currently one of the development and research directions of vehicle power sources that have received much attention.Among them,the thermal management system is an important component of the on-board proton exchange membrane fuel cell system.A reasonable thermal management system can ensure the stability of its internal operating temperature,improve its output performance,relatively extend its working life,and is one of the effective guarantees for the stable operation of vehicles.Therefore,it is of great significance to study the thermal management system of the on-board proton exchange membrane fuel cell.Based on the internal electrochemical reaction principle,heat transfer principle,and mass conservation law of the vehicle proton exchange membrane fuel cell system,combined with the heat transfer characteristics of the proton exchange membrane fuel cell stack and heat management system components,a lumped parameter dynamic model of the vehicle proton exchange membrane fuel cell,including the stack voltage model,energy model,and heat management system component model,is established;Based on the established lumped parameter model,the vehicle mounted fuel cell was operated under two operating conditions,respectively,in the ambient temperature range of0 to 10 ℃ and 30 to 40 ℃.The variation rules of the coolant temperature and output voltage of the proton exchange membrane fuel cell under different arrangement sequences of the cooling water tank and radiator in its heat dissipation components were analyzed,including the inlet temperature and outlet temperature of the system stack coolant,Study the parameters such as the temperature difference between the inlet and outlet and the stack output voltage to determine the appropriate arrangement order of different thermal management components under different operating conditions under changing ambient temperature;Analyzes the importance of coolant flow and cooling air flow in the thermal management system of proton exchange membrane fuel cell for stack temperature control,selects fuzzy PID control,adjusts control parameters,formulates fuzzy control rules,and derives adaptive control formulas.With the stack coolant outlet temperature and radiator coolant outlet temperature as control objectives,establishes a flow controller model for the fuel cell thermal management system;Adaptive control and fuzzy PID control are selected as the coolant flow controller and radiator cooling air flow controller for the thermal management system through thermal power step conditions.The effectiveness of the corresponding controller is analyzed using parameter curves such as coolant temperature and stack output voltage at different locations in the thermal management system under operating conditions.The results show that the relevant parameters all have reasonable changes within a reasonable range,meeting the corresponding control requirements.