A Modified Semi-Active Topology for Battery-Ultracapacitor Hybrid Energy Storage System for EV Applications

To cater fluctuating load demands in battery operated electric vehicles (EVs), ultracapacitors (UC) are now-a-days being employed as a secondary energy source along with the battery. Considering EVs where size and space of the energy storage system (ESS) is of utmost importance, a modified semi-active configuration for hybridizing lithium ion battery (LiB) with ultracapacitor has been proposed in this work. The hybrid energy storage system (HESS) configuration comprises of a bidirectional dc-dc converter with an effective control scheme to ensure the desired operation of the HESS and also for regulating the power distribution between the LiB and the ultracapacitor module. The performance parameters of the proposed HESS configuration have been evaluated through simulation using MATLAB/Simulink tool and then verified in experimentation using a scaled down bidirectional converter with its control logic validated through dSPACE-1103 controller board.