DC Microgrid Control Strategies
This PhD research developed a hierarchical control scheme for low-voltage DC microgrids, connecting passive converter control, dual-window DC bus signalling and rule-based power management. The stabiliser and signalling method were developed in this work and integrated with droop control into one scheme.
Stable Converters, Coordinated Sources
A DC microgrid connects generation, storage and loads to a common DC bus through power converters. Running it reliably requires two things at once: each converter must remain stable as converters interact on the bus, and the sources and storage must agree on operating roles, such as which one regulates the bus voltage and when batteries charge. Hierarchical control addresses these at different time scales, from fast local current and voltage loops, through droop-based power sharing, to supervisory power management.
A Three-Layer Control Framework
Passive control for Boost converters stabilises the interface converters. A high-pass-filtered compensator suppresses oscillation without the steady-state voltage shift of constant-gain compensation.
Dual-window bus signalling separates normal droop operation from deliberate voltage messages, so converters can exchange coordination commands through the power bus.
Rule-based EMS assigns bus regulation, charging and discharging roles, and limits PV output when storage cannot absorb the surplus.
Laboratory Microgrid
The scheme was implemented on a low-voltage laboratory microgrid in which interface converters connect emulated generation, battery storage and loads.
Related work examines how voltage variation and line resistance affect droop power sharing, extending the same question: how local converter behaviour can support reliable operation of the network.
PhD thesis: Control Strategies for Low Voltage DC Microgrids, Chapters 4–6. · Passive-control paper · Dual-window signalling paper