Topology And Control Of DC-DC Converter For Fuel Cell Vehicle

With the rapid economic development of countries,the number of conventional fuel vehicles is growing rapidly,consuming large amounts of oil resources and imposing a huge ecological burden on the planet.There is an urgent need to develop clean energy technologies to improve the environment and meet the challenges of energy use.Fuel cell vehicles are widely used in practice for their high-density current output,clean power generation,and efficient operation.A voltage difference between the fuel cell side output voltage and the vehicle DC bus voltage.In order to match the voltage difference between fuel cell vehicle and electric vehicle DC bus,a new DC-DC converter is proposed,which has the advantages of non-isolated structure,high voltage gain and low device stress.Before all others,by analyzing the traditional converter topology,this thesis proposes a new converter topology.The proposed converter has low voltage stress and high voltage gain,and the switch tubes are common ground,so that no additional EMI problems are generated at the input and output.Secondly,the proposed DC-DC converter is analyzed and calculated comprehensively,and the voltage gain equation and the voltage and current stresses of the switching tubes and diodes are derived and analyzed.Then,modeling the converter using small signal analysis method to find the transfer function of the converter.Then,the proposed converter circuit structure and control program are simulated and verified to prove the reliability of the converter topology and control program.Since the demand power of the vehicle changes frequently during the driving process of the fuel cell vehicle,especially in the congested urban roads,the proposed converter is also simulated under actual working conditions.Finally,a 100 W prototype was built in the laboratory,using DSP28335 as the main control chip.In order to simulate the actual operating condition of a real fuel cell vehicle converter,artificial perturbations are added to the experiment.The experiments prove that the converter can output preset voltage stably in the presence of disturbances,which is consistent with the theoretical calculation results and shows that the proposed converter works well in dynamic environment.