Research On Topology And Fault Diagnosis Of DC-DC Converter For Fuel Cell Vehicle

In order to solve the problem of environmental pollution,the automotive industry is shifting its research and development focus from traditional fuel vehicles to new energy vehicles.Fuel cell vehicles have become a development trend in the new energy vehicle industry due to their non-polluting and high energy density.However,the output voltage of the fuel cell is lower than the DC bus voltage of electric vehicle.At the same time,the output current increases,the output voltage drops significantly.In order to meet the high gain and wide-range input voltage requirements of DC-DC converters for electric vehicle fuel cells,this dissertation proposes a non-isolated DC-DC converter and studies the proposed converter from the aspects of the converter’s working principle,performance analysis and fault diagnosis.First,the principle analysis and working performance analysis of the proposed converter are carried out,and the voltage gain and device stress calculation formulas of the converter are derived,and compared with some existing DC-DC converters from the voltage gain,device stress and device.On this basis,the device parameter calculation and device selection of the proposed converter are carried out.Secondly,in order to ensure the safe and stable working of the converter,a set of power switch fault diagnosis strategy is designed for the proposed converter.First,through the analysis of the fault characteristics of the converter,the inductor voltage signal and the drive signal are selected as the fault diagnosis characteristic quantities.On this basis,a set of fault diagnosis strategies based on logic gate circuits are designed,and the proposed faults are analyzed in detail in principle.The effectiveness of the diagnostic strategy.Finally,Psim and Simulink models are built to verify the proposed converter and fault diagnosis strategy,Designing an experimental prototype with a rated power of 100 W to verify the proposed converter.According to the results of parameter calculation and device selection,the schematic diagram and PCB board of the converter are drawn,and DSP28335 is used as the main control chip for control program design.When the experimental prototype has input disturbance and load disturbance,the output can be stabilized at 200 V and the efficiency of the converter under rated conditions is 85.1%.The experimental results are consistent with theoretical calculations,verifying the effectiveness and rationality of the proposed converter.