The goal of this semester project is to create a thermal model of a electronic circuit board that will be used to control a Brushless DC motor for the project “Solar Impulse”. For this project, the finite element (FEM) software Ansys is used to build the model and to then apply the thermal loads. The software will calculate the temperature of the circuit board. The modeling using FEM is applied as it is not possible to make an analytical model for a complicated configuration like in this case.