Performance enhancement of a dynamic voltage restorer

Authors: LATHA PAPPATH VASUDEVAN, VALSALAL PRASAD

Abstract: Custom power devices are widely employed to mitigate power quality issues affecting critical loads. The dynamic voltage restorer is one of the custom power devices designed to inject a voltage in series with line to present a pure sinusoidal voltage of the desired RMS value to the sensitive loads, if the supply side is affected by voltage disturbances. The design and implementation of a DVR with a quasi-impedance source inverter and variable structure control is discussed in this paper. The voltage boosting ability of a quasi-impedance (Z) source inverter is used here to improve the performance of the DVR with reduced energy storage. The control system designed based on variable structure control effectively supports the DVR with good dynamic response, even under parameter variations. Performance of the proposed system in a single phase network is evaluated against the conventional DVR system using MATLAB simulation studies. An experimental model of the proposed system was developed to validate the simulation results. Implementation of the proposed DVR in a 3 phase distribution system is investigated with the help of simulation studies.

Keywords: Custom power devices, dynamic voltage restorer (DVR), quasi Z source inverter, variable structure control

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