Research On Electric-electric Hybrid Power System Of Hydrogen Fuel Cell Bus

With the intensification of environmental pollution,greenhouse effect and energy shortage,it is urgent to find new energy sources for automobiles.The hydrogen-oxygen proton exchange membrane fuel cell is considered to be the most ideal vehicle power,but the fuel cell has the disadvantages of slow dynamic response,long start-up time,and high price,which makes it difficult to meet the needs of independently driven vehicles.Therefore,it is of great significance to study the fuel cell and power battery electric-electric hybrid power system for the application of fuel cells in automobiles.Based on the PEMFC electrochemical principle,a PEMFC electrochemical Simulink simulation model including Nernst voltage,activation overvoltage,ohmic overvoltage,concentration overvoltage,and double-charge layer effect was established.Through simulation,the factors affecting the performance of PEMFC are analyzed.After that,a fuel cell system simulation model including a PEMFC stack,a cathode/anode gas supply system,and a temperature system was established.By controlling the air compressor,back pressure valve,pressure reducing valve,air release valve and coolant water pump,the operating parameters of the PEMFC system are maintained within a reasonable range.Based on the AVL-Cruise platform,a bus model was established,and the established PEMFC system Simulink model was coupled to obtain the FC+B bus electric-electric hybrid system.The energy distribution of the constructed bus electricelectric hybrid system was analyzed based on Simulink established fuzzy energy management strategies,fuel cell operating state control strategies,and vehicle driving state control strategies.Based on the DLL dynamic link library,the simulation of the model is performed.The simulation results show that the operating parameters of the PEMFC system are stable within a reasonable range in the CCBC cycle condition interval,which verifies the effectiveness of the PEMFC system model and its control;The established strategy can control the operating status and output power of the PEMFC system,and reasonably allocate the required power of the entire vehicle,so that the SOC value of the power battery is stable within a reasonable range;when the discharge current of the power battery is too large,the fuel cell can provide protective power To achieve the purpose of protecting power batteries.