A Double-Loop Inertia Phase-Locked Loop With Antidisturbance Ability

Power grid disturbance usually degrades the performance of phase-locked loop (PLL), which may cause the stability issue of grid-connected inverter. Considering the power grid disturbance, including voltage amplitude, grid frequency, and grid stiffness, a double-loop inertia phase-locked loop (DLI-PLL) with antidisturbance ability is proposed. In addition, the mechanism and characteristics of the proposed DLI-PLL are analyzed based on the unit step response of transfer function. The inertia of the proposed DLI-PLL can be controlled by adjusting the control parameters. Compared with the single-loop inertia phase-locked loop, the proposed DLI-PLL have better grid synchronization performance in case of grid frequency fluctuation. Meanwhile, due to the inertial control of angular frequency, the designed DLI-PLL has good antidisturbance ability. Finally, experimental results validate the effectiveness of the proposed DLI-PLL.