Adaptive controller based on grid impedance estimation for stable operation of grid-connected inverters under weak grid conditions

Temiz, Hakan
Keysan, Ozan
Demirok, Erhan
An electric grid having high impedance seen from the connection point is considered as a weak grid and it adversely affects the system stability of grid-tied voltage source inverters in renewable power devices. In this study, an adaptive controller is proposed by configuring the settling time of the phase-locked loop based on the estimated grid impedance. Pseudorandom binary sequence injection and Fourier techniques are carried out for grid impedance estimation. Impedance-based stability analysis is performed for a predetermined steady-state operation point. The proposed method is verified by a 300-kVA inverter prototype for wide-range grid impedance varying from 0.3 to 3 mH.


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Citation Formats
H. Temiz, O. Keysan, and E. Demirok, “Adaptive controller based on grid impedance estimation for stable operation of grid-connected inverters under weak grid conditions,” IET POWER ELECTRONICS, pp. 2692–2705, 2020, Accessed: 00, 2020. [Online]. Available: