Research On Modeling And Control Of Fuel Cell/Super Capacitor Hybrid Power Supply System

Hydrogen is a high-calorie,low-pollution,renewable secondary energy source.Hydrogen-fueled proton exchange membrane fuel cell has the advantages of high efficiency,no pollution,low noise,and strong environmental adaptability.The fuel-cell/supercapacitor hybrid power supply system is a promising hydrogen energy utilization system that can be used as a small mobile power generation device,backup power supply,power device,etc.The system is a nonlinear,strongly coupled system with complex dynamic characteristics and many influencing factors.Its modeling methods and control methods are practical significance.This paper takes the fuel cell/supercapacitor hybrid power supply system as the research object,and mainly carries out the following work:(1)The fuel cell stack voltage model is established by Matlab/simulink,and the fuel cell polarization characteristic curve is obtained.The comparison with the measured data shows that the polarization characteristics of the model are basically consistent with the actual system.The simulation parameters such as battery inlet pressure,battery temperature and membrane humidity are changed,and the fuel cell output voltage is positively correlated with the inlet pressure,battery temperature and membrane humidity.(2)The model of fuel cell/supercapacitor hybrid power generation system is established by Matlab/simulink,and the system energy management strategy and control method are proposed.The energy management unit divides the system into six operating modes according to the system state,and gives the reference power of the fuel cell and the super capacitor in each mode;the control unit controls the operating current of the fuel cell and the super capacitor according to the reference power.The simulation results show that the hybrid power supply system can respond quickly when the load power is abrupt,and meet the requirements of rapid load change.(3)The start-stop experiment and the variable-load experiment are carried out using the "10kW hydrogen utilization system".The experimental results show that during the start-stop process and the load-changing process,the super capacitor can respond quickly,the fuel cell gradually increases the output power,and the load voltage is basically kept stable.It shows that the energy management strategy and control method proposed in this paper can effectively guarantee the system power supply and has certain practical value.