Distributed Thermal Monitoring of Wind Turbine Power Electronic Modules Using FBG Sensing Technology

This paper reports a distributed thermal monitoring scheme for power electronic modules (PEMs) in wind turbine converters. The sensing system is based on utilizing electrically non-conductive and electromagnetic interference immune fiber Bragg Grating (FBG) sensing technology embedded in the PEM baseplate. The design and implementation features of the proposed scheme are presented first. The scheme is then applied in a commercial PEM operating within an inverter bridge, equipped also with a conventional distributed thermal monitoring system using a multiple point thermo-couple (TC) sensor suite. A range of tests are performed to evaluate the performance of the FBG distributed thermal monitoring system and correlate it to TC measurements under steady-state and transient operating conditions representative of PEM operation in an actual wind turbine application. It is shown that the proposed FBG monitoring system can offer practical operational improvements in establishment of distributed thermal sensing schemes for wind turbine PEM.