Modified non‐adaptive bandpass filter based phase locked loop. Issue 18 (7th July 2020)

• Record Type: Journal Article
• Authors: Verma, A.K.; Jarial, R.K.; Mohan Rao, U.
• Is Part Of: Electronics letters. Volume 56:Issue 18(2020)
• Page Start: 951
• Page End: 954
• Publication Date: 2020-07-07
• Subjects: proportional control -- power grids -- adaptive filters -- phase locked loops -- band‐pass filters -- curve fitting; modified nonadaptive bandpass filter -- phase locked loop -- demodulation -- pre‐filtering technique -- single‐phase grid variables -- grid voltage parameters -- synchronous reference frame phase‐locked loop -- modified bandpass filter -- pre‐filtering stage -- DC‐offset -- simple proportional controller -- in‐loop filtering burden -- phase information -- curve fitting technique -- PLL scheme -- grid disturbances; Electronics -- Periodicals; 621.381
• DOI: 10.1049/el.2020.1227
• Languages: English
• ISSNs: 0013-5194

Abstract

Abstract : In this Letter, a demodulation based pre‐filtering technique is proposed for fast detection of the single‐phase grid variables. The estimation of grid voltage parameters is achieved through a Type‐I synchronous reference frame phase‐locked loop (PLL). The modified bandpass filter in the pre‐filtering stage ensure a better rejection of the DC‐offset and harmonics. Thus, the grid variables are estimated rapidly with the help of a simple proportional controller. Consequently, in‐loop filtering burden and the effort required to tune the PLL is minimal. However, steady errors are witnessed in the fundamental amplitude and the phase information which are mitigated by a curve fitting technique. Importantly, the proposed PLL scheme has improved the dynamic performance under off‐nominal frequency conditions with immunity against grid disturbances. The robustness of the proposed algorithm is experimentally verified vis‐à‐vis existing literature.