Contents Introduction
Energy storage systems and renewable energy sources (RES) are expected to play a key role in the future utility power grid, especially in connection with smart grid applications [1]. Microgrids (MG) as proposed by Lasseter et al. [2] are thus of increasing interest in terms of a reliable integration of energy storage systems and renewable energy sources. Since a lot of MG components such as photovoltaics or storage technologies are intrinsically in DC and additional power converter stages are expensive, DC microgrids attract a high level of attention [3]. However, the control and management of a MG to ensure an optimal operation is a challenging task regardless of the application. Power flow control strategies, that operate the interfacing power converter stage of a MG component, constitute an important element to prevent for example batteries from critical conditions such as overcharging and deep discharging [4]. Coordinated control is a crucial task to ensure both stable and reliable operation, especially in the case of heterogeneous BESS [5]. Thus, the focus of this work is on PFCS for heterogeneous multiple BESS as shown in Fig. 1, whereby RES, loads and line losses are neglected.
Schematic of a DC MG composed of a BESS, RES, load and BESS control, where the typical architecture of a BESS is shown in bold.
