S. Abdul Rahman
University of Gondar

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Maximum voltage sag compensation using direct converter by modulating the carrier signal S. Abdul Rahman; Gebrie Teshome
International Journal of Electrical and Computer Engineering (IJECE) Vol 10, No 4: August 2020
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (890.806 KB) | DOI: 10.11591/ijece.v10i4.pp3936-3941

Abstract

The aim of this paper is to achieve maximum voltage sag compensation of 52% using direct converter based DVR. The DVR topology has only two switches. The DVR is designed to compensate the voltage sag in a phase by taking power from the same phase. A direct converter is connected between the series transformer and the line in which sag compensation is to be achieved. If the actual amplitude of the error signal is used and the amplitude of carrier signal is kept at 1 unit, it is possible to achieve only 22% of sag compensation. If the amplitude of the carrier signal is modulated according to the percentage of existing sag, 52% of the sag is compensated through ordinary PWM technique with the THD less than 5%. Matlab Simulation results are presented for the validating the analysis.
Voltage sag compensation using direct converter based DVR by modulating the error signal S. Abdul Rahman; Estifanos Dagnew
Indonesian Journal of Electrical Engineering and Computer Science Vol 19, No 2: August 2020
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v19.i2.pp608-616

Abstract

The aim of this paper is to present a modulation technique to achieve highest voltage sag compensation using direct converter based dynamic voltage restorer (DVR). The DVR topology proposed in this paper, has a direct converter and a series transformer. The direct converter is fabricated using only two bi-directional switches. The DVR is designed to compensate the sag in a phase by taking power from the same phase. The direct converter is connected between the series transformer and the line in which sag compensation is to be achieved. Conventionally, the PWM pulses for the direct converters are produced by comparing the error signal with the carrier signal. The error signal is obtained by comparing the amplitude of voltage in the line with the amplitude of the reference voltage. If the amplitude of the carrier signal is kept constant and the actual amplitude of error signal is used for PWM generation, it is possible to achieve only 22% of voltage sag compensation. But if the error signal amplitude is modulated according to the amplitude of existing voltage sag in the line, 52% of the voltage sag can be compensated with the THD less than 5%. Simulation results are presented for validating the analysis.