Research On Fuel Cell Vehicle Hybrid Power System And Energy Management Control Strategy

With the extensive use of cars around the world,the oil consumption increasing and the environmental pollution problem, which caused by the vehicle retain quantity keeps increasing is urgent to be solved. The existence of the car around the world with a increasing amount have been causing some serious problems like depletion of oil resource and environment issues. And all these issues are so urgent for human being to work out. At this time, the fuel cell electric vehicle which works for environmental protection and energy saving attracts the world’s attention. As we know, fuel cell has soft output,poor of dynamic response and it is incapable of recycling braking energy as well as mixed using with super-capacitor and battery, which makes the study of fuel cell car hybrid power system a hot topic in the field of fuel cell electric vehicle.The main research content is summarized as follows:First of all, at present the advantages and disadvantages of three hybrid power systems are compared, discusses the necessity that using battery and super-capacitor to provide cars energy. The three input DC-DC convert topology has been designed for hybrid system, pulse unit and the buffer unit combination method was used to construct a new type of three ports converter, traditional multiple single input converter is replaced as auxiliary energy connected to the direct current bus of the intermediate links, simplified the system structure. That parallel to the direct current bus with fuel cell formed a hybrid power system of the three input DC-DC converter topology in this paper, which will analyze the way hybrid power system works in different situation.Secondly, according to the requirement of cars’ acceleration performance determine the total power of the power source, and then we need to change the mixing degree and β to adjust the different ratios of the total power sources in three different energy source. Statistical analysis of vehicle power and fuel economy simulation results under different allocation schemes,to determine the best optimal hybrid power system power allocation scheme.Finally, management of energy was not thought highly of the shock caused by frequent changes in power to fuel cell and battery by now. In this paper, the wavelet transform and fuzzy logic are used in hybrid system energy management strategy for the energy dynamic management. The wavelet transform is used in energy management strategy to real-time processing the load power single, the energydistribution based on the change frequency division power demand single, not only meet the power required by the load of vehicle, but also reduce the bad influence on the fuel cell and battery caused by demand power transient change. Based on fuzzy control on the system of energy management, we take the effective control on battery and super capacitor to make sure that the battery and super capacitor value in setting the scope of the SOC. By improving system performance to prolong the service life of fuel cells, battery and reduce fuel consumption. Model of hybrid system has been set up in Matlab/Simulink to test the certify validity and effectiveness of the energy management strategy. The three input DC-DC converter in vehicles under different working mode switch working state of the feasibility and the correctness of the theoretical analysis has been verified.