Exploring Converter Control Duality in Microgrids: AC Grid-Forming vs DC Droop Control
New paper shows AC and DC microgrid controls are mathematically identical, enabling unified design...
A team of researchers from ETH Zurich and ABB (Jovan Krajacic, Ognjen Stanojev, Mario Schweizer, Orcun Karaca, Gabriela Hug, Vladan Lazarević) has published a paper on arXiv that reveals a fundamental duality between AC grid-forming control and DC droop control in microgrids. The work, accepted for the 2026 IEEE International Conference on DC Microgrids (ICDCM), shows that these two control strategies—long considered distinct due to operating in different physical domains—are actually mathematical duals.
The paper demonstrates isomorphism across four key areas: small-signal converter models, inner current control structures, power-sharing mechanisms (comparing the AC swing equation to DC capacitor power balance), and disturbance signals with dynamic response. The theoretical analysis was validated through simulations on simple converter setups. This finding could enable a unified control design framework for both AC and DC microgrids, potentially simplifying development and improving interoperability between the two systems.
- AC grid-forming and DC droop control are shown to be mathematical duals across 4 key aspects
- Duality includes small-signal models, current control, power-sharing (swing equation vs capacitor balance), and disturbance response
- Accepted for presentation at 2026 IEEE International Conference on DC Microgrids (ICDCM)
Why It Matters
Unified control design could streamline microgrid development and improve AC/DC system interoperability for renewable energy integration.