Adaptive Harmonic Impedance Reshaping Control Strategy Based on a Consensus Algorithm for Harmonic Sharing and Power Quality Improvement in Microgrids With Complex Feeder Networks

Abstract

In islanded microgrids with complex feeder networks, distributed generation units (DGs) and loads can be freely connected to any node, leading to changes in the feeder impedance between nodes and the microgrid structure. However, traditional harmonic sharing control methods encounter difficulties with microgrids with complex topologies. Additionally, existing techniques essentially require constructing additional harmonic virtual impedance, possibly resulting in conflict between voltage quality and harmonic sharing effectiveness. To address this issue, this paper proposes an adaptive harmonic impedance reshaping method based on a consensus algorithm. The proposed method adaptively reshapes the inverter harmonic impedance by introducing harmonic current feedforward compensation control and impedance reshaping factor adaptive control, which can achieve accurate harmonic sharing while greatly improving the voltage quality of the microgrid. The proposed method avoids constructing additional harmonic virtual impedance and can be applied to microgrids with complex feeder networks and variable structures without acquiring prior microgrid configuration knowledge. Moreover, the proposed method is a fully distributed control, where the microgrid central controller (MGCC) is not required. Furthermore, the control parameter design method based on modeling and stability analysis is discussed in detail. Finally, simulations and experiments verify the feasibility and effectiveness of the proposed method.