Carrier Phase Synchronization Based on Circulating Current Identification for Distributed Inverters

Distributed parallel inverters are a promising solution for large power systems due to their flexibility and reliability. However, the distributed control mode often causes carrier phase desynchronization among the control units, leading to adverse effects on high-frequency harmonics and power loss. To address this issue, this article proposes a carrier phase synchronization (CPS) method for distributed parallel inverters, leveraging circulating current identification. In the proposed scheme, circulating currents in parallel inverters directly influence high-frequency harmonics and carry carrier phase information. The peak amplitude of these currents is used to identify the CPS point and adaptively adjust the carrier phase difference. The proposed strategy leverages existing circulating currents to achieve CPS in parallel inverters, eliminating the need for additional synchronization hardware. Consequently, this solution not only reduces system costs and size but also enables CPS-based multifunctionality, such as power quality optimization and common mode reduction. Finally, both simulation and experimental results are provided to validate the effectiveness of the proposed CPS method and the associated analysis.