Research On Control Strategy Of Hydrogen Fuel Cell Heavy Truck

Hydrogen fuel cell vehicles have the advantages of clean and efficient,diverse fuel sources,and long driving range,so they have received widespread attention.Control strategy is an important core technology of hydrogen fuel cell vehicles.It has a major impact on the power,economy and reliability of the vehicle.This thesis takes the hydrogen fuel cell heavy truck as the object of researching,and the control strategy is the core.Carried out the research on the power system selection and parameter matching,vehicle control strategy,energy management strategy and vehicle modeling and control strategy simulation optimization,The main work is as follows:(1)Comparing the different power system structures of fuel cell vehicles,it is determined that the hydrogen fuel cell heavy truck hybrid power system structure uses the fuel cell as the main and the power battery as the auxiliary.According to the requirements of hydrogen fuel cell heavy truck and the types and classification and characteristics of various parts of the power system,the selection is completed.According to the vehicle design parameters and power performance indicators,the parameter matching calculation of each core component has been completed.(2)According to the structure and function of the hydrogen fuel cell heavy truck vehicle control system,the vehicle control strategy is studied from three aspects: vehicle drive control,AMT shift control,and brake energy recovery control.The vehicle driving control strategy converts the driver’s operation of the accelerator pedal into the motor torque coefficient through a linear relationship.The aim of AMT shift strategy is to minimize the acceleration time,and the current gear is determined by the opening of accelerator pedal and the current speed.The braking energy recovery strategy takes into account driving safety and fuel economy,and reasonably allocates regenerative braking force and mechanical braking force.(3)The energy management strategy of hydrogen fuel cell heavy truck is studied,the suitable working range of fuel cell system and power battery is determined,and the control logic and execution mode of power following control strategy are analyzed.Considering the impact of frequently changing output power on fuel cell,an ALPF energy management strategy is proposed.The vehicle demand power is allocated through adaptive low-pass filter and logic rules.So as to ensure that the fuel cell system provides low-frequency power,and the rest of the power is borne by the power battery.(4)MATLAB/Simulink was used to build a hydrogen fuel cell heavy truck vehicle simulation model.The method of combining forward and backward simulation is used to verify the rationality of the power system parameter matching and the effectiveness of the control strategy.The simulation research shows that the hydrogen fuel cell heavy truck meets the power requirements.The fuel economy and the output power fluctuation degree of the fuel cell system under the power following control strategy and the ALPF energy management strategy are compared respectively.It can be seen from the simulation results: the fuel economy of the two energy management strategies is basically equivalent,but the ALPF energy management strategy can effectively suppress the fluctuation of the output power of the fuel cell system.Finally,in order to improve the fuel economy of the hydrogen fuel cell heavy truck and the endurance of fuel cell,the Pareto genetic algorithm is used to optimize the ALPF with multiple objectives.Under the premise of ensuring the working efficiency of the fuel cell system and the level of hydrogen consumption of the vehicle,the output power fluctuation of the fuel cell system is further reduced by 9.28%.