Research On Energy Management Optimization Of New Power Supply Tram Hybrid Power System

Hydrogen fuel cell is the key vehicle energy carrier to achieve zero carbon product.Unified with the advantages of efficient braking energy recovery of high-capacity energy storage components,meanwhile,the construction of a new power supply system tram hybrid power system has gradually became an ideal solution for the current collection of tram without catenary.However,the diversification of energy storage components makes energy management more complex,and the lack of fuel economy obviously restricts the course of massive commercialization in the field of rail transit.Therefore,taking energy conservation,cost reduction,dynamic performance enhancement and overall efficiency as the core objectives,the construction of typical driving conditions of tram,live efficiency allocation technology and operation optimization of rail transit hybrid motive force system are central argument of the full text.The work carried out is as follows:Firstly,in order to accurately reflect the instantaneous driving characteristics of tram,and then provide a theoretical basis for the calculation of power system energy consumption and energy supply,a new method of working condition construction based on multi-dimensional Markov chain is proposed.The sample database is composed of the measured line data of many cities in China,and the dimension of the characteristic parameters is reduced by principal component analysis,and the driving characteristics are divided by cluster analysis.The traditional Markov chain is extended to the multi-dimensional state space,and the threedimensional state transition probability matrix of train speed,average acceleration and road slope is constructed.The random number is generated by the combination of cumulative Poisson distribution function and MCMC sample to ascertain the operation state at the next time,so as to obtain the real-time working condition.Through error analysis,it is verified that the proposed method can truly deduce the actual operation characteristics of tram.Secondly,in view of the problem of over reliance on expert experience and poor adaptability of working conditions in the dynamic power distribution of lithium battery / super capacitor hybrid energy storage system for tram,it is proposed to introduce the working conditions of tram into the input of traditional fuzzy control,formulate the membership function and domain according to the driving conditions,redress peak value corresponding moment of EDLC,and optimize the dynamic performance of train.In the meantime,select PSO for weight optimization of fuzzy control rules,so as to reduce the peak current of lithium battery,extend the cycle appliance life of auxiliary energy storage system of tram and guarantee the power demand meanwhile;An example shows that the proposed strategy can effectively avoid the defect that the traditional rule control can not achieve the global optimal power allocation.Lastly,in order to deal with the features of expansive electrification load spreading,strong impact,strong pulsation and wide frequency domain variation of electrification load in tram driving conditions,an energy management strategy suitable for fuel cell hybrid power system is proposed.Based on the equivalent hydrogen consumption theory,the mathematical model of adaptive adjustment of energy factor with SOC of energy storage system is deduced.The objective function of minimizing equivalent hydrogen consumption is rewritten as maximizing external energy consumption to improve the robustness of the system to load change.The online operation verification of the proposed strategy is carried out under the constructed multidimensional driving condition scenario.The results show that the advantages of the proposed strategy are high energy density,high power density and high hydrogen efficiency.