Mobile QR Code QR CODE : The Korean Institute of Power Electronics
Title An Adaptive Digital Notch Filter for Stabilization of Single-Phase Grid-Connected Inverters With LCL Filter
Authors 허진용(Jin-Yong Heo) ; 김학수(Hak-Soo Kim) ; 노의철(Eui-Cheol Nho)
DOI https://doi.org/10.6113/TKPE.2021.26.5.307
Page pp.307-314
ISSN 1229-2214
Keywords Grid-connected inverter; LCL filter; Stabilization; Digital notch filter
Abstract Even though the LCL filters have superior harmonic attenuation ability to L filters, stability has always been an issue. The system could be unstable because of the resonance phenomenon, especially when digital controller is used. Adding a notch filter to the compensator is one approach to solve the problem. Resonance phenomenon can be inhibited by aligning notch frequency to system resonance frequency. However, resonance frequency variation can be obtained because the actual system has a nonstationary characteristic. Therefore, the system could be unstable, where the system parameters are changed when the conventional notch filter is used. An adaptive digital notch filter that stabilizes the system even system parameters are changed. Simulation and experiment results are provided to verify the validity of the proposed adaptive filter.