Sizing Electric Storage Devices for Power Smoothing Applications in DC Microgrids

Converter technologies powering drive systems established direct current technology in industrial applications. Recent developments expand the regular Direct Current (DC) link from a multi-axis-drive-systems to an interlinked multiple machine supply system. The extended DC-link allows for the exchange of recuperated energy between different processes and increases the overall system efficiency. The comparison of the extended DC link and the DC microgrids shows that the integration of multiple supply systems, like distributed generation and storage systems, allows for further optimization with respect to reliability, efficiency and robustness. One possible optimization strategy is to reduce dynamic load peaks with a storage system and downsize the grid infeed converter. Several applications for power smoothing can be found in literature, however there is no approach for sizing storage capacity and power for these applications. This paper introduces a systematic approach, which aims for storage sizing based on a load profile of industrial machines.