Research On Energy Management Strategy Of Mixed Power System With Contactor

With the urbanization process in China,the development of urban rail transit can ease the traffic pressure and optimize city space structure.The power supply in traditional urban rail transit mainly comes from the catenary,but increasingly intensive urban planning and construction cause inconvenience for the erection of catenary.For problems above,vigorously developing the vehicle energy storage equipment has become one of the solutions,and working reasonably and efficiently of the power system,which consists of the energy storage equipment,is very important.This paper will study the energy management strategy of the power system of a 100%low floor tram.The main work of this paper includes:(1)According to the mixed power structure composing of battery pack and super capacitor stack of a 100%low floor tram,two kinds of different power system topology with contactors are proposed.(2)Study how the two battery packs sharing a DC/DC converter work,and the conditions that the two battery packs can work in parallel on the premise of security and no circumfluence are derived.Using MATLAB/Simulink simulation to verify the conditions of no circumfluence,and put forward the circumfluence control strategy of two parallel battery packs.(3)For the two kinds of different power system structure,according to the power demand of the bus operation and the capacity of battery discharging,two power distribution strategies are developed respectively.And then take equalization control to the power source.Finally,the simulation results of MATLAB/Simulink show that the effect of equalization control is good.(4)For the phenomenon of overcharge and overdischarge,time delay of contactors'action,and time delay of DC/DC converters' transformation of operating mode,control strategies are proposed respectively in this paper,and then the design of the energy management controller is improved.With the power supply system and the controller based on MATLAB/Simulink and Stateflow,the simulation results show that the energy management controller designed is effective,and the power curve of the composite power sources can track the demand power curve of the train well.