Cooperative Inverters to Overcome PLL Malfunctions

This article introduces a cooperative strategy between grid-interactive inverters to prevent undesired trips of inverters due to Phase-Locked Loop (PLL) malfunctions. The PLL is typically used to measure the inverter’s phase-angle at the Point of Common Coupling (PCC). Accurate phase-angle measurement is critical for grid-interactive inverters to stay synchronized with the power grid and independently control active and reactive power. The cooperative strategy utilizes the phase-angles of inverters at their PCCs in a region to identify any possible PLL malfunctions, exchanges data, and then enables the inverters to make corrective decisions. In this article, the efficacy of the cooperative strategy is verified through simulation results in MATLAB/Simulink environment.