Meshed DC microgrid hierarchical control: A differential flatness approach

In this paper, a meshed DC microgrid control architecture whose goal is to manage load balancing and efficient power distribution is introduced. A novel combination of port-Hamiltonian (PH) modeling with differential flatness and B-splines parametrization is introduced and shown to improve the microgrid's performance. A three layer supervision structure is considered: (i) B-spline parametrized flat output provide continuous profiles for load balancing and price reduction (high level); (ii) the profiles are tracked through a MPC implementation with stability guarantees (medium level); (iii) explicit switching laws applied to the DC/DC converters ensure appropriate power injection. Each level functions at a different time-scale (from slow to fast), and the control laws are chosen appropriately. The effectiveness of the proposed approach is evaluated by simulations over a DC microgrid composed by a collection of solar panels (PV), an energy storage system (ES), a utility grid (UG) and a consumers' demand.