A rapid prototyping environment for DC and AC microgrids: Smart energy integration Lab (SEIL)

This paper introduces an automated and reconfigurable laboratory environment for rapid prototyping of DC and AC microgrids. The laboratory includes seven fully programmable power converters, 47.5 kWh lithium-ion battery, configurable AC loads, a set of AC busbars with configurable network impedances between them, a set of DC busbars and relevant monitoring and control equipment. Each laboratory element includes its own local embedded controller connected via Ethernet link to a centralized control system. In contrast to other laboratory facilities already reported in the literature, SEIL allows DC and AC microgrids to be emulated simultaneously, it is highly reconfigurable (on both AC and DC sides), provides great versatility due to its hierarchical control system architecture and in addition to that allows connection and testing of any other external equipment in the 100 kW range. A case study will be used to demonstrate how the laboratory can be configured and operated to test a microgrid with multiple AC and DC connections. The test case assumes a DC microgrid interconnecting an AC islanded microgrid, an emulated traction substation, a lithium-ion battery and an existing AC grid. The primary control objective is to maintain the DC bus voltage constant, while an Energy Management System (EMS) is deployed to manage the power flows in the microgrid.