A Multi Input Converter for Interfacing Battery and Supercapacitor to the Load

Abstract

Hybrid Energy Storage System (HESS), i.e. battery assisted by supercapacitor is used to safeguard the battery from power surges, which can be much greater than the steady state power requirement. These power surges severely deteriorate the battery lifetime. In a conventional HESS, two converters are used, one for battery and the other for supercapacitor. This could be expensive since one of the converters has to be rated for the surge power requirement. In this paper, a multi input converter has been proposed, in which the supercapacitor directly supplies the load without any power conversion stage during high power demand. To compensate for the changing supercapacitor voltage, a compensating voltage has been added to the supercapacitor output. This leads to reduced ratings for the required power electronic conversion stages for the HESS. Battery current is regulated to protect the battery from sudden current changes, thus increasing its lifetime. Simulation results have been presented for the proposed converter, which show that the proposed converter serves the purpose of regulating the load voltage and protecting the battery from power surges.