Table of Contents
ISRN Electronics
Volume 2013, Article ID 361643, 8 pages
Research Article

Transformer Magnetizing Inrush Currents Using a Directly Coupled Voltage-Source Inverter

Division of Electricity, Department of Engineering Physics, Swedish Centre for Renewable Electric Energy Conversion, Uppsala University, P.O. Box 534, 751 21 Uppsala, Sweden

Received 20 July 2013; Accepted 19 September 2013

Academic Editors: J. Abu Qahouq and J. Doval-Gandoy

Copyright © 2013 Rickard Ekström 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.


The connection of a power transformer to the grid is associated with magnetizing inrush currents that may result in power quality issues as well as faulty relay tripping. In distributed generation, the transformer may instead be premagnetized from the source to avoid this. In this paper, a VSI is directly coupled to a transformer. Three different strategies of premagnetization are implemented into the control system, and the inrush currents are measured for various values of the remanent flux in the core. The results show good reduction in the peak magnetizing inrush currents without using any external circuitry.