Evaluation of Hardware-in-the-Loop-based Converter/Inverter Digital Twins for Microgrids Using the OPC Unified Architecture Platform

This paper compares the average output error rates of the information models of converters/inverters based on actual microgrid equipment with those designed using Hardware-in-the-Loop (HIL). The microgrid environment implemented at the Mirae building of Seoul National University of Science and Technology was virtually designed using HIL, and Open Platform Community Unified Architecture (OPC UA) information models were employed to digitalize the converters/inverters of each microgrid as virtual assets. The microgrid environment designed in HIL equipment consists of three batteries, three converters, two inverters, a photovoltaic (PV) system, and the Mirae building load including three EV chargers. To verify the similarity between the actual and simulated microgrid, a scenario was executed where the batteries were charged and discharged at 20 kW, 0 kW, and -20 kW in 10-minute intervals. The average error rates of the output power of the converters/inverters information models implemented via OPC UA ranged from a minimum of 0.38% to a maximum of 9.60%. Consequently, it was verified that the Mirae building digital twin, designed based on HIL and OPC UA, can operate similarly to the actual environment, ensuring an average error rate below 9.60%.