A thermal enclosure model for inverters

Design of a suitable thermal model, inclusive of the enclosure or cabinet, is an integral part of power electronic thermal management. This stems from the fact that power losses in an inverter may cause severe temperature rise in the enclosed cabinet, causing damage to the inverter switches or components. A thermal enclosure model for a 3φ, back-to-back inverter topology rated 24 kVA, kept in an enclosure having dimensions 1.524 × 1.066 × 1.828 cubic metre is presented. An enclosure air temperature calculation algorithm has been proposed to calculate the enclosure air temperature in steady state when power losses in the inverters and enclosure material and dimensions are the only known parameters. Effects of the enclosure air temperature on the heat-sinks and switches of the back to back inverter have also been investigated for the above mentioned inverter topology. The enclosure air temperature is calculated with an error less than 3%.