Data-Driven Voltage Secondary Control for Microgrids

This paper presents a secondary voltage Koopman-based control for an alternate current microgrid (MG). Following the hierarchical control frame for MGs, secondary voltage control is designed using two different approaches. In the first case, a linear approach is used for model predictive control using droop equations and measurements of the reactive power. In a second case, the voltage controller is designed using the Koopman operator in a data-driven strategy using only measurements of the voltage, which allows managing the nonlinear behavior of voltage as a linear problem in the space of observables of the Koopman operator, making it suitable for the model predictive control design. Both cases are simulated in an MG model, for which the Koopman-based approach shows satisfactory results regulating the voltage in the presence of load changes.