A Simple Three-Level Switching Architecture to Enhance the Power Delivery Duration of Supercapacitor Banks in Electrified Transportation

Abstract

Hybridization of supercapacitors (SCs) with batteries in electric vehicular applications improves battery life, acceleration, and driving range. However, the efficiency of the power electronic interface that unites batteries and SCs is affected due to wide voltage variations at the SC bank terminals. Moreover, the SCs in a bank offer low storage capacity that restricts them from serving a series of transients on a single charge. This article aims at improving the power delivery duration and energy utilization of SCs with controlled terminal voltage variations using a new bank switching configuration. A simple three-level transition control scheme is implemented for charge and discharge of the SC bank. The effectiveness of the proposed topology is validated using PLECS simulations and experimental studies on a laboratory-developed prototype. Furthermore, the suitability of the proposed SC bank in a hybrid energy storage system (HESS) for an electric vehicle is verified in accordance with varying load demands. The superiority of the proposed architecture is shown in terms of the SC bank voltage variations and depth of discharge under standard urban and highway drive cycles.