Power Management of Supercapacitors using Auxiliary Bank Switching for Hybrid Energy Storage Systems

The hybridization of battery and supercapacitors (SCs) forms a highly effective energy storage system (ESS) for the electrified transportation that offers both energy and power at the same time as per the load requirements. However, the SC bank in hybrid ESS (HESS) deficits in delivering power for a longer duration to serve a higher number of transients. To reduce the burden on batteries and the overall system cost, a new auxiliary bank switching strategy for SCs with enhanced power delivery duration is introduced in this paper. A simple power management control is proposed to effectively switch the SCs from parallel to series combinations while serving the dynamic load demands. The key performance of the proposed circuit is holistically evaluated using PLECS simulations and a scaled-down laboratory prototype in terms of maximum power delivery time and SC cell energy utilization. The impact on passive components of the bi-directional converter with proposed architecture in terms of current stress is analyzed in detail. Finally, the suitability of the proposed architecture in HESS for an electric vehicle (EV) is verified on an OPAL-RT real-time simulator under a standard new European driving cycle.