Decentralized Frequency Restoration in Islanded Converter Base Microgride

Variation of frequency and voltage by load changes in a microgrid is a challenge in droop control method. Centralized restoration frequency or voltage in a microgrid requires communication link and therefore affects the advantage of decentralized droop control such as reliability, simplicity and inexpensiveness. This paper proposes a decentralized method that restores the frequency of a microgrid without any communication link and maintains these advantages. The method detects signal changing by wavelet transform (WT) to synchronize distributed energy resource (DER) that interfaced by converter to microgrid. Its operation principle and control method are explained and analyzed. The simulation results are presented to validate the effectiveness of the proposed method.