A novel high-speed flywheel based DC voltage source with soft handover capability

A novel high-speed flywheel-based DC voltage source (FDCS) has recently been developed as a direct and improved energy storage substitute for chemical batteries in uninterruptible power supply (UPS) applications. Like chemical batteries, the FDCS requires only a DC connection to a UPS with no other interconnections; however, the FDCS offers many advantages over chemical batteries, including reduced life cycle costs due to elimination of the periodic replacement of chemical batteries, increased power density, known state of charge, and the absence of environmentally harmful materials. The FDCS also incorporates a novel soft handover feature which was developed to provide a gradual load transfer from the backup energy source of the UPS to a backup engine-generator set (genset). In the absence of the soft handover feature, the genset fails due to its inability to slew its output power in the time required to continue to supply the critical load. This paper details the performance of the FDCS during operational events and shows the benefits of the soft handover feature for a combined genset-UPS ride-thru application