Integration methodology of ultracapacitor-battery based hybrid energy storage system for electrical vehicle power management

摘要

Nowadays electrical vehicles are in demand and the developments in their field are increasing which is required to improve the performance of the vehicle in terms of single range to cover. An efficient energy storage device is required to improve the performance and the efficiency of an EV. Power requirement of EV is dynamic in nature which requires a high energy and high power density source. A single source cannot fulfill this requirement. Thus efficiency of an EV can be improved by hybridization of different energy storage sources. This paper discusses an approach to interface the ultracapacitor source with the battery using sliding mode controlled bidirectional DC-DC converter. The EV is operating in different operating modes such as normal mode, cruise mode and acceleration/deceleration mode. To utilize the full capability of both the sources, a rule based energy management system is developed and these rules are based on certain empirical values. The hybrid power source is used to supply the momentary (peak) load and as well as average load demands of an electrical vehicle. The complete e-rickshaw vehicle simulations have been carried out in MATLAB/SIMULINK environment with pulse load condition as well as vehicle as load using real time Indian city drive cycle. It is observed from the results that ultracapacitor takes up the pulse load current effectively in fully controlled manner in an active HESS.