Power Quality Improvement for Grid Connected Inverters under Distorted and Unbalanced Grids

- Journal title : Journal of Power Electronics
- Volume 16, Issue 4, 2016, pp.1578-1586
- Publisher : The Korean Institute of Power Electronics
- DOI : 10.6113/JPE.2016.16.4.1578

Title & Authors

Power Quality Improvement for Grid Connected Inverters under Distorted and Unbalanced Grids

Kim, Hyun-Sou; Kim, Jung-Su; Kim, Kyeong-Hwa;

Kim, Hyun-Sou; Kim, Jung-Su; Kim, Kyeong-Hwa;

Abstract

A power quality improvement scheme for grid connected inverters, even in the presence of the disturbances in grid voltages due to harmonic distortions and three-phase imbalance, is presented for distributed generation (DG) power systems. The control objective is to force the inverter currents to follow their references with robustness even under external disturbances in grid voltages. The proposed scheme is realized by a disturbance observer (DOB) based current control scheme. Since the uncertainty in a system can be effectively canceled out using an estimated disturbance by the DOB, the resultant system behaves like a closed-loop system consisting of a disturbance-free nominal model. For experimental verification, a 2 kVA laboratory prototype of a grid connected inverter has been built using a digital signal processor (DSP) TMS320F28335. Through comparative simulations and experimental results under grid disturbances such as harmonic distortion and imbalance, the effectiveness of the proposed DOB based current control scheme is demonstrated.

Keywords

Distorted and unbalanced grid;Distributed generation;Disturbance observer;Grid connected inverter;Power quality;

Language

English

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