Oscillation phenomenon of grid-connected inverter can be caused due to time-varying grid impedance. Terminal output impedance of inverter can be reshaped by re-tuning internal parameters of inverter to mitigate the oscillation issue. However, it's not easy to obtain internal parameters of gridconnected inverter in practical operation. This paper presents a gray-box parameters identification method to identify the parameters of LCL filter, the proportional coefficient of current controller and capacitor-current-feedback coefficient from the measured terminal impedance frequency responses by using vector fitting algorithm. When instability phenomenon of multipleparalleled inverters system occurs, the internal parameters of each inverter are first identified by using the proposed method. Then, the capacitor-current-feedback coefficients are re-tuned to stabilize the studied power system according to the impedancebased stability criterion. The re-designed parameters for the specific grid condition can be delivered to the manufacturers for further parameters modification. Simulation results are given to validate the proposed gray-box parameter identification and corresponding impedance reshaping method.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.