The Effect of Phase Locking Error on Control of Grid-Connected Inverter in Distribution Network

The phase-locked loop provides a phase reference for the coordinate transformation in grid-connected inverters to ensure synchronous operation and power output. In the distribution network, under the conditions of three-phase unbalance because of the diversity of loads, untransposed line and the complex operating conditions, the phase-locked loop can produce phase locking errors that affect the inverter power output and thus the regulation of the active distribution network. Therefore, by analyzing the inverter control, the influence of phase error of the phase-locked loop on the Park transformation and modulation signal is deduced, and the relationship between phase error, voltage, current, current reference value, and modulation signal is quantified. The simulation results prove the correctness of the analysis.