Currently, high power density and compact size converters are widely used and being extensively developed. Heatsinks also occupy a large volume affecting the power density, size of the converters and ensuring stable operation. This paper presents a model for estimating the losses of MOSFETs, thermal resistance of heat sink when incorporating the impact of cooling fans. Following this, a proposition is presented for the selection of appropriate heatsink and fan parameters. The validity of the proposed model and the effectiveness of these techniques are verified through simulations conducted using Ansys Icepak