Development Of DC/DC Power Supply Unit For Fuel Cell

Fuel cell is a device that converts hydrogen and air into electrical and thermal energy,which is a very environmentally friendly way to generate electricity.However,the fuel cell output characteristics are soft and its lifetime is affected by ripple.As the fuel cell stack increases,the output current keeps increasing and the output voltage decreases with the increase of current,which is vulnerable to the load.Based on this,a 7.5k W fuel cell DC/DC power supply unit is developed in this paper,with the following main work.(1)analyze the mechanism and external characteristics of the fuel cell,and for the low voltage and high current applications of the fuel cell power system,summarize the characteristics of the matching DC/DC converter with high gain,low ripple and high conversion efficiency(2)Through comparison,several existing fuel cell DC/DC power supplies are analyzed,and the topologies of non-isolated and isolated types are compared and analyzed,and the advantages and disadvantages of different topologies and their application scenarios are summarized.The main circuit topology is the Dual-Active-Bridge(DAB),which is connected in the form of Input-Parallel Output-Series(IPOS)to achieve Zero-Current Switching(ZCS)and Zero-Voltage Switching(ZVS)on the primary side,and Zero-Voltage Switching(ZVS)on the secondary side.and Zero-Voltage Switching(ZVS)of the secondary-side switching tubes,resulting in a significant reduction in switching losses and a significant improvement in the transmission efficiency of the fuel cell DC/DC power supply.(3)The operating principle of the fuel cell DC/DC power supply topology is analyzed,modeled and analyzed,the switching losses of the power module are calculated,and the high-frequency transformer and fuel cell DC/DC power supply monitoring system are designed.(4)The MATLAB/Simulink simulation tool is used to establish the simulation model.Finally,a 750V/7.5k W fuel cell DC/DC power supply platform is built based on the theoretical analysis,parameter calculations and experimental results,and the experimental results verify the rationality of the circuit structure and parameter design.