Decreasing fossil energy sources require the search for alternative ways of individual transport. An important step is the electrification of the drive train and further vehicle components, enabling a total control of the overall energy flow while at the same time offering more degrees of freedom in optimizing the vehicle architecture.
This paper describes an energy management system for battery electric vehicles. Main component of the system is a load balancing strategy which smoothens the energy flow and reduces high current fluctuations, reducing energy losses while increasing the battery lifetime.
The first part of the paper describes a central ECU, which has been developed as a vehicle management unit. Driving strategy as well as the energy management strategy are implemented on this ECU. A bench test has been developed to test the ECU hardware as well as software in a laboratory environment.
The second part of the paper describes in detail the simulation model of the vehicle used, a Tata Indica Vista EV. The model concentrates on the energy flow within the vehicle and includes sub-models of all relevant components of the vehicle, for example the traction and starter batteries, or loads like the heating system. A comparison of simulation and measurements proves the validity of the simulation model.
The last part of the paper describes the energy management strategy. Energy savings, the reduction of load peaks and the reduction of microcycles have been evaluated using the simulation model during different drive cycles, indicating an increase of the battery lifetime.