Distributed Control Strategy for Low-Voltage Three-Phase Four-Wire Microgrids: Consensus Power-Based Control

Most of the distributed control strategies for grid-connected power converters are droop-based approaches composed of converters driven in voltage-control mode, based on local and shared data with adjacent units. They are usually combined with consensus protocols to deal with the trade-off between power sharing accuracy and voltage/frequency regulation. To achieve the desired results these control systems usually incorporate other techniques and need to take into account details of primary control dynamic. Additionally, power flow control and current unbalance compensation at the PCC are rarely addressed in such approaches. Contrariwise, the centralized control strategy power-based control has been successful in achieving these functionalities. It is oriented to a set point selection to the whole system, considering converters driven in current-control mode and a central converter in voltage-control mode. However, the dependence on centralized communication network in this method still requires improvement. Thereby, the complementary features of both strategies are combined herein in the consensus power-based control, based on a master/slave peer-to-peer integration using sparse communication. This model-free approach provides all aforementioned benefits to the grid without any other technique. Implementation complexity and costs are decreased, while the flexibility and reliability are enhanced. All these achievements are demonstrated by simulation results under different operational conditions and compared to previous works.

Automated summary

Most distributed control strategies for grid-connected power converters are droop-based approaches with converters driven in voltage-control mode, combined with consensus protocols. These strategies balance power sharing accuracy and voltage/frequency regulation, while centralized power-based control successfully achieves power flow control and current unbalance compensation. The complementary features of both strategies are combined in consensus power-based control, improving flexibility and reliability without additional techniques.