Research On Control Strategy Of Fuel Cell Electric Vehicle Energy Management System

With the continuous reduction of fossil fuel reserves and the increasingly serious problem of environmental pollution,the development of clean energy has become a hot topic of social and economic development.New energy vehicles are well developed in this context.As a new type of new energy vehicle,fuel cell vehicle has broad research prospects in the field of new energy vehicles with its advantages of zero pollution,noise-free,long life and easy maintenance.At the same time,it can provide new ideas for solving energy crisis and pollution problems in the future."Fuel cell+battery?FC+B?"fuel cell hybrid electric vehicle is taken as the research object.The fuel cell is the main energy source,and the accumulator is the auxiliary energy device.Both of them provide the power for the vehicle driving.The reasonable distribution of output power between different power sources is an important part of the fuel cell vehicle energy management system.The thesis proposes two energy management strategies.One is an improved finite state machine control strategy.The other is hybrid fuzzy logic control strategy.In the improved energy management strategy of finite state machine,P_FCmin?minimum output power of fuel cell?and P_FCmax?maximum output power of fuel cell system?are introduced.The energy management strategy is divided into three control modes:low SOC,medium SOC and high SOC,and 15 control rules have been formulated.The SOC of battery and load demand power are used to dynamically adjust the distribution of energy flow in different power sources to improve the vehicle economy.Based on this,the target value of SOC(BSOC_tag)is introduced in hybrid fuzzy logic control strategy.It uses IF-THEN rules to design the main fuzzy controller and sub-fuzzy controller respectively,so as to determine the appropriate fuel cell system output power distribution coefficient?,which will ensure the power performance of fuel cell vehicle and power balance control,give full play to the advantages of fuel cell and battery.MATLAB/Simulink simulation platform was used to verify the proposed improved finite state machine and composite fuzzy logic energy management strategy,and to make a comparative analysis with the power tracking strategy.Simulation results show that,both proposed energy management strategies can meet the power demand in the actual working condition.When the initial SOC of the battery is too low or too high?taking BSOC=39.8%and BSOC=80.2%as examples,respectively?,compared with the power tracking strategy,both proposed strategies make the battery SOC closer to the target value;when the initial SOC of the battery is moderate?taking BSOC=60%as an example?,the proposed strategies are more efficient and can save fuel.Proposed strategies are more flexible and have certain practical value.