Thermal modeling of a medium frequency transformer

Author:	Kalle Ilves
Title:	Thermal Modelling of a Medium Frequency Transformer
School:	Royal Institute of Technology
Date:	March 2009
Type:	MastersThesis

Abstract
This thesis covers thermal modeling of a medium freuqency transformer. The
geometry of the transformer and the thermal properties of the di erent parts
are used to derive thermal resistances that can be put together in an equivalent
circuit describing the thermal system. The transformer is immersed in oil and
it is found that convective heat transfer through the oil must be included in the
model. The dynamic behaviour of the transformer is also modeled by including
thermal capacitances in the circuit.
The model is evaluated by measuring the primary winding and core temperature
while the transformer is heated. The primary winding temperature is measured
by measuring its electical resistance. The chosen method is discussed along
with the di erence between the measured and estimated response of the
thermal system

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