A Novel Distributed and Hierarchical Control Method for the Series-Parallel-Type Microgrid

The series-parallel-type microgrid has been proposed to integrate various distributed generation (DG) units, such as photovoltaic (PV) and energy storage. This article further proposes a novel distributed and hierarchical control method for accurate power sharing and restoration of AC output voltage magnitude. First, the basic working principle of the series-parallel-type microgrid has been briefly introduced, based on which the proposed method is elaborated. Each converter module only communicates with its neighboring converter module, and the central controller is not needed, which avoids the failure of central controller on the whole system and increases the reliability. The correction values of AC voltage magnitude and angular frequency are calculated. The proposed method is suitable for both resistive-inductive (RL) and resistive-capacitive (RC) loads. Evaluation results are provided to validate the feasibility of the proposed method.