Three-Level Hierarchical Microgrid Control

Research Question

How can a microgrid coordinate primary, secondary, and tertiary control levels in a unified hierarchical architecture, and can such an architecture be validated on physical hardware rather than only in simulation?

Method

This project developed a three-level hierarchical control architecture for islanded microgrids:

• Primary control — local droop-based voltage and frequency regulation at the inverter level, acting on millisecond timescales to stabilize the system after disturbances.
• Secondary control — centralized restoration of voltage and frequency to nominal values, compensating for the deviations introduced by primary droop control.
• Tertiary control — economic dispatch and power flow optimization, managing energy distribution among sources and storage over longer time horizons.

The architecture was implemented in a hardware-in-the-loop (HIL) laboratory platform, connecting real controllers to a real-time simulated microgrid. This bridged the gap between pure simulation and full physical deployment, allowing validation of control timing, communication delays, and equipment constraints that pure simulation cannot capture.

Personal Contribution

Frederik Banis was a co-author. He contributed to the laboratory implementation and experimental validation, working on the integration of control layers and the HIL testing setup. The first author (Mateo Beus) led the model development and overall architecture design.

Validation and Key Results

• The three-level control architecture was successfully implemented and tested on a HIL platform, demonstrating coordinated operation across all control levels.
• The laboratory validation confirmed that the hierarchical scheme maintains stable frequency and voltage under load changes and source switching, beyond what simulation-only validation could guarantee.
• The HIL setup revealed practical timing and communication constraints that informed the control design.

The method was published in Electric Power Systems Research (2020), a peer-reviewed journal.

Outputs

• Journal paper: DOI 10.1016/j.epsr.2020.106758
• PhD thesis: Efficient Operation of Energy Grids, DTU, 2020. DOI 10.11581/DTU.00000334

Collaborators

• DTU Compute, Technical University of Denmark — Niels Kjølstad Poulsen (supervisor)
• University of Zagreb — Mateo Beus (first author), Hrvoje Pandžić (supervisor)

Status and Next Steps

Status: Published (2020). This project distinguishes simulation from physical implementation — the HIL validation is the key contribution beyond pure modeling.

Transfer to current research: The closed-loop experimentation architecture — measure, infer, decide, act, with physical validation — is the same pillar that now drives human-supervised autonomous bioassay platforms. The shift is from energy hardware to biomedical hardware, but the closed-loop validation methodology is shared.

See the Methods page for the closed-loop experimentation pillar and the Research page for the broader research program.