Delay Compensation Strategy Incorporating Parameter Identification and Newton Interpolation for Grid-connected Inverter

With the development of "double high" in the power system, the proportion of renewable energy connected to the grid through the grid-connected inverter is increasing. However, the control delay introduced by the grid-connected inverter will change the impedance characteristics of the grid-connected inverter, causing resonance risk in the grid-connected system and threatening the security of the grid. The internal control delay parameters of the grid-connected inverter at the project site are undisclosed due to confidentiality. To address this issue, a delay compensation strategy is proposed for grid-connected inverter, which combines parameter identification and Newton interpolation. Firstly, the Loewner matrix is utilized to improve the vector matching, and an impedance transfer function of the grid-connected inverter is proposed to realize the correct identification of the control delay parameters of the grid-connected inverter. A compensation delay method based on Newton interpolation is given on this basis, which aims to reshape the impedance of the inverter by compensating the delay time required in the control system, so as to suppress the system resonance. Finally, the correctness and effectiveness of the proposed method are verified through simulation.