Research On Control Method Of Thermal Management System Of Vehicle Proton Exchange Membrane Fuel Cell

At present,hydrogen fuel cell vehicles have received extensive attention due to their high efficiency and cleanliness.Proton Exchange Membrane Fuel Cell(PEMFC)has the advantages of high energy conversion efficiency,high reliability,and zero emission.It has broad application prospects in the automotive field.However,the life and output performance of proton exchange membrane fuel cells are affected by many factors,among which temperature is one of the key factors affecting the output characteristics of the PEMFC system.The optimal working temperature of PEMFC is between 60℃ and 80℃.Effective thermal management of proton exchange membrane fuel cells is one of the key factors to improve the safety,durability and operating efficiency of hydrogen fuel cell vehicles.This article introduces the development status at home and abroad from four aspects:PEMFC temperature characteristics,thermal management system model,thermal management control method,and thermal management method verification.PEMFC will generate electricity and heat during the working process.Based on the three types of energy losses that PEMFC will produce during reactive power generation,a PEMFC voltage model is established,and the effect of temperature on the output power and output voltage of PEMFC is analyzed.According to the law of conservation of internal energy in the PEMFC stack,the thermal management system model is established,including the stack temperature dynamic model used to analyze the heat generation of the PEMFC stack,as well as the water tank model,radiator model and water pump model to prepare for the formulation of thermal management control methods.Through the analysis of the thermal management system,the control requirements for the thermal management of the PEMFC for vehicles are formulated.Due to the inherent non-linear characteristics of PEMFC and the uncertainty of parameters,a fuzzy control method is proposed to control the temperature of the entrance and exit of the PEMFC stack,so that the temperature of the entrance and exit of the stack is maintained at a set value.Because the membership function of the fuzzy controller relies on expert experience,it is proposed to apply genetic algorithm to optimize the membership function of the fuzzy controller,so that the control accuracy of the fuzzy controller is higher.In order to verify the effectiveness of the proposed method,a hydrogen fuel cell vehicle was selected,and a hybrid model of PEMFC and battery was built.According to the PEMFC work efficiency curve,a rule-based energy management strategy was proposed.Two standard operating conditions of WLTC and HWFET are selected to verify the thermal management method.The simulation results show that the thermal management control method proposed in this paper can effectively control the temperature of the inlet and outlet of the stack.Meanwhile,the fuzzy controller optimized by genetic algorithm has higher control accuracy than the unoptimized fuzzy controller.The deviation between the temperature and the set value is lower.