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Mathematical Problems in Engineering
Volume 2015 (2015), Article ID 790584, 23 pages
http://dx.doi.org/10.1155/2015/790584
Research Article

Control Strategy of Three-Phase Photovoltaic Inverter under Low-Voltage Ride-Through Condition

1Department of Electromechanical Engineering, Faculty of Science and Technology, University of Macau, Macau
2Information Engineering College, Henan University of Science and Technology, Luoyang, China

Received 19 June 2015; Accepted 1 September 2015

Academic Editor: Xinggang Yan

Copyright © 2015 Xianbo Wang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The new energy promoting community has recently witnessed a surge of developments in photovoltaic power generation technologies. To fulfill the grid code requirement of photovoltaic inverter under low-voltage ride-through (LVRT) condition, by utilizing the asymmetry feature of grid voltage, this paper aims to control both restraining negative sequence current and reactive power fluctuation on grid side to maintain balanced output of inverter. Two mathematical inverter models of grid-connected inverter containing LCL grid-side filter under both symmetrical and asymmetric grid are proposed. PR controller method is put forward based on inverter model under asymmetric grid. To ensure the stable operation of the inverter, grid voltage feedforward method is introduced to restrain current shock at the moment of voltage drop. Stable grid-connected operation and LVRT ability at grid drop have been achieved via a combination of rapid positive and negative sequence component extraction of accurate grid voltage synchronizing signals. Simulation and experimental results have verified the superior effectiveness of our proposed control strategy.