A novel phase estimation method for renewable energy grid-connected equipments

Abstract

When renewable energy is applied to the power grid, it will cause problems such as harmonic interference and changes in grid frequency, resulting in harmonic distortion of the inverter and other renewable energy grid-connected equipments output current. So the grid-connected environment of weak grid puts forward higher requirements on the performance of phase-locked loop (PLL). Therefore, these renewable energy grid-connected equipments require Phase-Locked Loop (PLL) with higher technical performance. Aiming at the control requirements of inverter and other grid-connected equipments in weak grid, an optimization method based on a novel PLL is proposed. The method uses a dual enhanced novel cascade second-order generalized integrator (DENCSOGI) to simultaneously filter out the fundamental voltage negative sequence (FVNS) component and the DC offset (DCO) voltage component, and it can speed up the dynamic response and phase-locked accuracy of the PLL. The proposed PLL is verified by the simulation experiment platform. The performance of the approach is excellent and the grid-connected power quality of the renewable energy grid-connected equipments is guaranteed.