Research On Modeling And Power Distribution Method For Hybrid Power System In The Fuel Cell Vehicle

Fuel cell vehicles are an important type of new energy vehicles,which use fuel cell systems and auxiliary energy sources to output energy to drive the vehicle forward.The fuel cell system has high energy utilization rate,and does not have the common charging problem of secondary batteries.It is the most balanced vehicle power device at present.The power distribution of the fuel cell vehicle hybrid power system is an important part of vehicle control strategy.A good power distribution control strategy will have a very important impact on the fuel economy and the use cost of the vehicle.This paper takes fuel cell vehicles as the research object and the hybrid system model is built.Based on the characteristic analysis of power system,an effective power distribution control strategy is developed by using the optimization algorithm.The specific research content is as follows:(1)The fuel cell models in this article use a fuel cell system as the main energy source and lithium-ion batteries as an auxiliary energy source.In view of the existing problems,based on the prototype of fuel cell system,lithium-ion battery and DC/DC converter,the mathematical modeling of the core components of fuel cell is completed based on MATLAB/Simulink,and an improved hybrid power system model is established.The gas supply system is controlled by the method based on the oxygen excess ratio,and the simulation verification is carried out.(2)The characteristics of the fuel cell system is analyzed,and propose a characteristic analysis idea based on working conditions.The characteristics of lithiumion batteries are analyzed,and a power estimation method under multi-parameter constraints is proposed.Based on AVL CRUISE,the vehicle parts are modeled and forward simulation is carried out.Realize the joint simulation of AVL CRUISE and MATLAB through the software interface of AVL CRUISE,and complete the construction of the simulation model of the hybrid power system.(3)Transform the power allocation problem into a non-linear programming optimization problem.The calculation method of equivalent hydrogen consumption is proposed,the behavior boundary of the power source that guarantees the life is set,the optimization is solved through SQP,and the power distribution strategy based on the nonlinear programming algorithm is proposed.It can be seen from the simulation results that the designed power distribution control strategy plays a positive role in improving the vehicle endurance performance,and at the same time it has strong adaptability under urban conditions.(4)According to the analysis results of the power source characteristics and the simulation results of the control strategy based on the optimization algorithm,the existing power following control strategy is improved.In the control strategy,the vehicle operating condition judgment condition and power estimation method are added.It can be concluded from the simulation results that the improved control strategy can play a positive role in improving the durability of the vehicle.