A modified demodulation technique for single-phase grid voltage fundamental parameter estimation

Md. Shamim Reza, Mihai Ciobotaru, Vassilios G. Agelidis

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)


This paper proposes a modified demodulation technique to provide accurate estimation of the single-phase grid voltage fundamental amplitude, frequency, and phase angle under distorted grid conditions. A quadrature oscillator is combined with a demodulation technique for rejecting oscillations at second harmonic generated by the demodulation of the fundamental voltage component; thus, it can provide more accurate estimation, as compared to a conventional one, using same-order and cutoff-frequency-based infinite-impulse-response low-pass filters after the demodulation stage. It also does not require a separate frequency estimation algorithm for adaptive demodulation as the frequency is obtained from the estimated initial phase by using a differentiation operation and an integral controller. The technique is relatively simple and can also reject the negative effects caused by harmonics under a wide range of fundamental frequency variation as specified by the standard requirements. When compared with a quadrature phase-locked loop technique, the proposed one provides improved estimation of the fundamental voltage parameters. The performance of the proposed technique is verified using both simulation and experimental results.
Original languageEnglish
Pages (from-to)3705-3713
Number of pages9
JournalIEEE Transactions on Industrial Electronics
Issue number6
Publication statusPublished - Jun 2015
Externally publishedYes


  • Demodulation
  • parameters estimation
  • quadrature oscillator and single-phase voltage system


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