Experimental Validation of a Grid-Aware Optimal Control of Hybrid AC/DC Microgrids

Abstract: This paper presents the experimental validation of a grid-aware real-time control method for hybrid AC/DC microgrids. The optimal control is leveraged by the voltage sensitivity coefficients (SC) that are computed analytically using the close-form expression proposed in the authors' previous work. The SCs are based on the unified power flow model for hybrid AC/DC grids that accounts for the AC grid, DC grid, and the Interfacing Converters (IC), which can operate in different control modes, e.g. voltage or power control. The SCs are used to express the grid constraints in the optimal control problem in a fully linear way and, therefore, allow for second- to subsecond control actions. The validation of the model is performed on the hybrid AC/DC grid, available at the EPFL. The network consists of 18 AC nodes, 8 DC nodes, and 4 converters to interface the AC and DC network. The network hosts multiple controllable and uncontrollable resources. The SC-based optimal control is validated in a generic experiment. It is shown that the real-time control is able to control the ICs optimally to redirect power through the DC grid, to avoid grid constraint violations while providing reactive power support to the upper layer AC grid. Furthermore, the computational time of the optimal control is analysed to validate its application in critical real-time applications.