Mode Adaptive Droop Control With Virtual Output Impedances for an Inverter-Based Flexible AC Microgrid

TLDR

Droop control is widely considered a good choice for managing power flows between microgrid converters in a decentralized manner. This paper proposes a decentralized power control method for a single‑phase flexible AC microgrid that uses droop control with a derivative controller to improve power‑loop dynamics in islanded mode. In islanded mode the droop controller is combined with a derivative controller, while in grid‑connected mode it is paired with an integral controller to enforce strict power‑factor control at the point of common coupling. Small‑signal analysis, simulation, and experimental results demonstrate that the scheme operates in both modes without mode‑switching actions, provides smooth transitions, and is relatively simple to implement.

Abstract

A decentralized power control method in a single-phase °exible AC microgrid is proposed in this paper. Droop control is widely considered to be a good choice for managing the power flows between microgrid converters in a decentralized manner. In this work, to enhance the power loop dynamics, droop control combined with a derivative controller is used in islanded mode. In grid- connected mode, to strictly control the power factor in the point of common coupling (PCC), a droop method combined with an integral controller is adopted. Small-signal analysis of the proposed control is shown both in islanded and grid-connected mode. The proposed control scheme does not need any mode switching action. Thus, it is relatively simple in control for full mode of operation. Smooth transitions between the operation modes and the effectiveness of the proposed control scheme are evaluated through simulation and experimental results.