Multisampling based Grid Impedance Estimation for Two-Cell Interleaved Three-phase Inverters

This paper presents a multisampling based grid impedance estimation method for two-cell interleaved three-phase grid-connected inverters. By comparing the sampled point of common coupling (PCC) voltage at the peak/valley and intersection points of the phase-shifted carriers, the grid impedance can be estimated under an inductive grid condition. Moreover, to reduce the estimation error, a compensation scheme based on the phase-locked loop (PLL) is developed. Finally, the effectiveness of the proposed method is verified through the experimental results.