Porous metal model for calculating slot thermal conductivity coefficient of electric machines

The calculation accuracy of Slot Thermal Conductivity Coefficient (TCC) is related to the estimation of temperature rise of electric machines, which is important in the process of improving motor's efficiency and working capacity. In this article, the Porous Metal Model (PMM) with a variety of filling materials considered is proposed to improve the accuracy of TCC. A simplified structure model and thermal resistance network of slots are established to investigate the equivalent TCC of a slot. The calculated result is verified by a 2-layer flat thermal conduction model, which is based on experiments and electromagnetic simulations. Moreover, TCC obtained through the PMM method is compared with the Parallel Method (PM) and Classical Estimate Method (CEM). The results show that the calculation method of TCC based on PMM is more accurate; besides, the formula only includes one variable usually fixed for a certain motor, so the proposed method is more suitable for the practical application.