An electrical circuit based 3-D thermal model of a fan cooled 600μH, 80A inductor for a plasma cutting power supply

This paper applies a 3-D electrical circuit based thermal model technique described in [1] to analyze the thermal performance of a 600 muH, 80 A inductor for a plasma cutting application. The forced convective heat transfer terms in the model are derived using the empirical correlation method [2, 3]. This approach is cost-effective since it does not use an FEA tool for the analysis. Also, the circuit based nature of the model facilitates seamless coupling of the magnetic and thermal physics that affect the inductor in a standard circuit simulator environment. A comparative evaluation of the simulation results with experiment shows that the average coil temperature error is in the 10-12% range while the average layer temperature error is in the 3-16% range. This is lower than that seen in [1] where errors in the range 25-40% are recorded. However, the model has limitations due to the presence of individual winding layer temperature errors in the range 18-50%. Factors affecting the performance of the model are also discussed in the paper.