Mobile QR Code QR CODE : The Korean Institute of Power Electronics
Title A Study on 3-level Interleaved Charger-Discharger for Uninterruptible Power Supplies
Authors Tae-Geun Koo ; In-Hwan Lee ; Young-Hoon Cho
Page pp.535-542
ISSN 1229-2214
Keywords 3-level converter ; Interleaved charger-discharger ; Neutral point voltage ; Uninterruptible power supply(UPS) ; Ripple current of battery inductor
Abstract This paper proposes a simple 3-level interleaved charger-discharger for the uninterruptible power supply (UPS) with various combinations of battery cells. The proposed converter not only improves charging and discharging efficiency, but also reduces the physical volume and the cost. Furthermore, the converter also offers the capability of the neutral point voltage, so that more stable operation can be obtained. In addition, the proposed converter significantly reduces the ripple current of the battery inductor, thereby providing an expected life extension of the battery. Experimental results for a 300kVA UPS prototype verify the validity of the proposed converter. The proposed charger-discharger is suitable for UPSs and energy storage systems (ESSs) with wide input battery voltage ranges.