Dynamic Consensus Algorithm based Distributed Unbalance Compensation in Islanded Microgrids

In islanded microgrids (MG), distributed generators (DG) can be employed as distributed compensators for improving the power quality (voltage unbalance and harmonics) in consumer side. Hierarchical control is usually applied with different control levels differentiated. In case of voltage unbalance compensation, droop control and virtual impedance can be applied in primary control to help the positive sequence active and reactive power sharing. Secondary control is used to assist voltage unbalance compensation. However, if transmission line differences are considered, the negative sequence current cannot be well shared among DGs. Accordingly, this paper analyzes the power flow in unbalanced islanded MG, proposes a dynamic consensus algorithm based distributed negative sequence current sharing method. Experimental results are shown to demonstrate the effectiveness of the method