Energy Management And Decision-making Of Urban Electric Bus

With the development of society,Urban problems have become increasingly prominent such as traffic congestion,environmental pollution and energy shortage.In order to realize the sustainable development of urban traffic,the Government attaches great importance to promoting the development of low carbon urban transportation,and promoting new energy vehicles,and raising the level of industrialization of electric vehicles.As a new type of zero-emission,pollution-free green transportation,the urban electric bus is paid more and more attention.Therefore,it's great significance to promote public transport system development and realize the energy conservation and emission reduction by researching the power system management strategy of urban electric bus and its key technology.Based on the current situation of the public traffic system operation in our country city,first,this paper analysis the dynamic characteristics of urban electric bus,and defined the calculation method of real-time power demand during the driving process.Then,by combing with the design of the vehicle parameters and target performance,it analysis the vehicle motor rated power and the energy requirements of and lithium battery and super capacitor.At last,the parameter matching design of each module of the hybrid power system is carried out.By analyzing the hybrid power system and the structure principle and performance characteristics of DC/DC power converter,this paper introduces the calculating method of state parameters in each module.Finally,the simulation model of the vehicle compound power system is established according to the logic structure of the hybrid power system.Through the analysis and study of logical threshold energy management strategy and fuzzy control energy management strategy,this paper built a Simulink simulation model,Based on traditional fuzzy control energy management strategy and logic threshold energy management strategy,this paper presents a fuzzy optimal design of controlled energy management strategy.Finally,the simulation analysis and comparison of different energy management strategies are carried out.Under different strategies,this paper compared to energy management strategy by analyzing percentage difference between energy consumption and target energy consumption percentage and braking energy recovery.It is concluded that the fuzzy control strategy can better meet the power requirements of the vehicle system,and the power allocation can be better and more effective than the other two management strategies.Then,this paper presents a long cycle of performance simulation,and the results show that the strategy can make reasonable distribution of power for lithium batteries and super capacitors.The strategy makes the input and output of the lithium battery group change smoothly,and effectively improve the life of the lithium battery pack,and can meet the performance requirements of the vehicle.