Research On Fuel Cell/battery Hybrid Power Supply System And Energy Management Strategy

Proton Exchange Membrane Fuel Cell(PEMFC)is a power device which generates electricity by hydrogen.PEMFC has the advantages of high efficiency,no pollution and high reliability.For the practical applications,research on PEMFC power system has important theoretical and practical value.Because of the problem of soft output characteristics and poor load capacity,a dual-input and dual-output buck-boost converter is proposed,and the energy management strategy for smooth switching is designed.The content includes:Firstly,the model of battery and PEMFC are established.According to the electrochemical working principle of PEMFC,the mechanism model is established.The genetic algorithm is used to optimize the relevant parameters in the model.Based on the data of the charge and discharge experiments and the Hybrid Pulse Power Characterization,the battery model is established.Secondly,according to the characteristics of the hybrid power supply system,a dual-input and dual-output buck-boost converter is proposed.The working principle and voltage relationship of the converter is researched in the single-input single-output mode,dual-input mode and dual-output mode.The inductor and capacitor is calculated and selected based on the duty cycle in each mode.Thirdly,in order to ensure the feasibility and reliability of the PEMFC hybrid power supply system,an energy management strategy is designed.Voltage and current closed-loop regulators are designed in each mode.According to the variety of fuel cell output current,the control mode is changed.The simulation results show that load voltage,PEMFC current and battery current can be stabilized in the single-input single-output mode,dual-input mode and dual-output mode.An experimental prototype of PEMFC and battery hybrid power supply system is built.The feasibility of the dual-input and dual-output buck-boost converter is verified by experiments.The experimental results show that the proposed control strategy can switch between single input and double input,single output and double output smoothly according to the load.