Meshed DC microgrid hierarchical control: A differential flatness approach

• Published in: Electric power systems research Vol. 180; pp. 106133 - 133
• Main Authors: Zafeiratou, I., Prodan, I., Lefèvre, L., Piétrac, L.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.03.2020; Elsevier Science Ltd; Elsevier
• Subjects: Automatic; Computer simulation; Control theory; DC microgrid; Differential flatness; Distributed generation; Electric converters; Electric power; Electric power distribution; Electricity distribution; Energy storage; Engineering Sciences; Flatness; Hierarchical control; Load balancing; Meshed topology; Parameterization; Photovoltaic cells; Port-Hamiltonian systems; Power balancing; Simulation; Solar energy; Spline functions; Switching; Voltage converters (DC to DC); Power balancing; Meshed topology; Differential flatness; DC microgrid; Port-Hamiltonian systems; Hierarchical control
• ISSN: 0378-7796; 1873-2046
• DOI: 10.1016/j.epsr.2019.106133

•Port-Hamiltonian modeling for explicit description of the power routing through a meshed DC microgrid.•Three layer hierarchical control accounting for fast and slow dynamics under uncertainties within the grid.•Differential flatness and subsequent B-spline parametrizations for continuous time profile generation.•Set invariance for constraints tightening in the profile generation procedure. 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.