Synchronization algorithms are of great importance in control of grid-connected inverters as an integral part of distributed power generation units such as photovoltaic systems. A new all-digital closed-loop phase-locked algorithm for the synchronization signals of three-phase grid-connected inverters is presented even considering seriously distorted and variable-frequency utility conditions. The proposed synchronization algorithm can suppress the negative sequence utility voltage at fundamental frequency and high-frequency harmonic components effectively, and lock the positive sequence phase at fundamental frequency accurately.Moreover, a frequency adaptation algorithm is also proposed for applications where large frequency variations are often expected. Finally, digital simulation and experimental results both prove the feasibility of the proposed phase-locked method. The introduced synchronization method provides higher degree of immunity and insensitivity to harmonics and other types of pollutions in the utility when used to synchronize inverters.
Digital Object Identifier (DOI)
Guo, Xiaorui and Guo, Jifeng
"A New Synchronization Algorithm for Grid-Connected Inverters,"
Applied Mathematics & Information Sciences: Vol. 08
, Article 49.
Available at: https://dc.naturalspublishing.com/amis/vol08/iss2/49