Multi-purpose droop controllers incorporating a passivity-based stabilizer for unified control of electronically...

Area of Science:

• Electrical Engineering
• Control Systems
• Power Systems

Background:

• Electronically-interfaced distributed generators (EI-DGs) are crucial for modern micro-grids.
• Maintaining stability during mode transitions (grid-connected to islanded) is a significant challenge.
• Existing droop controllers may not adequately address transient stability and power sharing in all micro-grid operational modes.

Purpose of the Study:

• To propose multi-purpose droop controllers for EI-DGs enabling seamless operation in grid-connected, islanded, and transient modes.
• To ensure accurate active and reactive power sharing among EI-DGs in islanded mode.
• To enhance transient stability and damping capabilities of EI-DGs during large disturbances.

Main Methods:

• Development of unique droop controller configurations for EI-DGs.
• Integration of a passivity-based control (PBC) stabilizer to dampen deviations using local information.
• Analytical investigation of primary source dynamics' impact on damping.
• Introduction of a novel compensator in the frequency-droop loop to counteract adverse effects of primary source dynamics.

Main Results:

• The proposed droop controllers facilitate stable operation in grid-connected, islanded, and transient modes.
• Effective active and reactive power sharing is achieved in islanded mode.
• The PBC-based stabilizer significantly improves transient stability and damping.
• Analytical results indicate primary source dynamics can attenuate damping, which is compensated by the novel frequency-droop loop compensator.

Conclusions:

• The developed multi-purpose droop controllers offer a robust solution for micro-grid stability.
• The integration of PBC and a novel compensator effectively addresses transient stability challenges posed by EI-DGs and their primary source dynamics.
• Simulation results validate the proposed strategy's superiority over existing methods.