Real time analysis of multi-level dual active bridge charger using quintuple phase shift modulation for battery energy storage system

Abstract

Abstract This study presents on board charger system designed specifically for the purpose of charging and discharging of the batteries used in electric vehicles (EVs). The conventional charger used in the EVs consists a three phase AC-DC converter and a DC-DC converter. In bidirectional isolated converter mostly dual active bridge (DAB) is used. But this converter produces more harmonics in the inductor current due to which more heating in the transformers and inductor takes place regardless of the modulation methods employed. Hence, the efficiency of the EV charger reduces. Keeping these limitations of the conventional DAB charger, in this paper a multilevel dual active bridge (MLDAB) converter based charger with quintuple phase shift (QPS) modulation has been proposed for the application in EVs. The control technique used in the proposed EV charger offers an enhanced control approach that results in the improved performance, while simultaneously ensuring a unity power factor. The charging algorithm has been constructed in a manner that enables it to effectively maintain voltage at the DC link to 650V. Moreover the proposed EV charger has been compared with the conventional DAB chargers with different modulation schemes. The results show that proposed EV charger produce less harmonics in the inductor current and hence the efficiency of the proposed charger is more than the conventional DAB converter based EV charger. The obtained simulation results are then validated using real time OPAL-RT results.