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Journal of Control Science and Engineering
Volume 2012 (2012), Article ID 684610, 21 pages
Research Article

Model-Based Fault Detection and Isolation of a Liquid-Cooled Frequency Converter on a Wind Turbine

1Innovation Center, KK-Electronic a/s, Bøgildvej 3, 7430 Ikast, Denmark
2Section of Automation and Control, Department of Electronic Systems, Aalborg University, Fredrik Bajers Vej 7C, 9220 Aalborg, Denmark

Received 11 April 2011; Revised 20 November 2011; Accepted 1 December 2011

Academic Editor: Ricardo Dunia

Copyright © 2012 Peng Li 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.


With the rapid development of wind energy technologies and growth of installed wind turbine capacity in the world, the reliability of the wind turbine becomes an important issue for wind turbine manufactures, owners, and operators. The reliability of the wind turbine can be improved by implementing advanced fault detection and isolation schemes. In this paper, an observer-based fault detection and isolation method for the cooling system in a liquid-cooled frequency converter on a wind turbine which is built up in a scalar version in the laboratory is presented. A dynamic model of the scale cooling system is derived based on energy balance equation. A fault analysis is conducted to determine the severity and occurrence rate of possible component faults and their end effects in the cooling system. A method using unknown input observer is developed in order to detect and isolate the faults based on the developed dynamical model. The designed fault detection and isolation algorithm is applied on a set of measured experiment data in which different faults are artificially introduced to the scaled cooling system. The experimental results conclude that the different faults are successfully detected and isolated.