Smart Battery Cells for Maximum Utilization in Power Electronics Dominated Grids

Abstract

This paper proposes a control scheme for maximum utilization of smart battery cells based on differential power processing (DPP) for application in power electronics dominated grids (PEDG). It is essential to supply uninterrupted power to critical and non-critical loads by using battery energy storage systems (BESS) in next generation power grid i.e., PEDG. The capability of BESS to provide uninterrupted power is highly dependent on the state of Charge (SOC) of individual battery cells in a battery string. Conventionally, the end of life (EOL) metric of BESS is limited by the battery with lowest SOC. Ultimately, this limitation constraints the total power injection capability of the BESS. In contrast, the proposed scheme estimates the differential power required to support the battery cells with lowest SOCs and thereby ensures a balanced discharge of the BESS. The required differential power is supplied by an auxiliary battery cell interfaced to the BESS via dual active bridge converter (DAB). Thus, the energy availability of the BESS is significantly enhanced while also minimizing the discharge stresses on the weaker battery cells while increasing the battery cell’s lifetime. The performance improvement obtained from the proposed smart battery cells is verified via several case studies. Furthermore, the superiority of the proposed approach is justified by comparing with conventional BESS control approach.