Consensus-based P-f and Q-V droop control for multiple parallel-connected inverters in lossy networks

Micro-grid is a system with various distributed energy sources integrated. Due to its inherent distributed and heterogeneous nature, the micro-grid becomes ideal platform for consensus-based multi-agent control. Conventionally, power sharing in a micro-grid is achieved by autonomous P-f and Q-V droop control on individual inverters, which suffers from lack of frequency restoration mechanism and dependence on output line impedance. While the previously developed Q-V droop control still ends up with inaccurate reactive power sharing under strongly non-uniform line impedance. In this paper, a consensus-based P-f and Q-V droop control with sparse communication network is proposed. With the networks considered to be lossy, its operation principle and control method are explained, and stability of the closed-loop system is investigated by the energy function approach. Simulation results of a 4-node 3-inverter system are then presented to validate the effectiveness of the proposed control method.