A Novel Power Flow Control Strategy for Heterogeneous Battery Energy Storage Systems Based on Prognostic Algorithms for Batteries

This work focuses on a novel power flow control strategy (PFCS) for a heterogeneous multiple battery energy storage system (BESS) based on prognostic algorithms for batteries and the selection of proper prediction horizons for such algorithms. Unlike existing PFCS, the proposed control strategy copes with the transition between power balancing and state of charge balancing regardless of the scenario, the system configuration or the objective of the operator due to the adaptability of the prediction horizons. MATLAB/Simulink is used to conduct a simulation study based on a heterogeneous multiple BESS. Therefore, the novel PFCS is implemented in a validated simulation model to prove its advantages in terms of the performance and efficiency target indicator in different scenarios and system configurations. The results show, the performance can be enhanced regardless of the scenario or system configuration and the efficiency is at least as high as for the reference PFCS.

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. Fig. 1:

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.