Evaluation of Impregnation Materials for Thermal Management of Liquid-Cooled Electric Machines

• In this paper, the thermal impact of using different impregnation materials on high-performance liquid-cooled electric machines is studied. In this regard, varnish, Epoxylite, and a silicone-based thermally conductive material are considered. To study thermal effects of using different impregnation materials in theory, an advanced lumped-parameter thermal model of the studied electric machines is developed. In addition to the simulation studies, three identical induction machines using the aforementioned materials are manufactured and evaluated. Experimental tests are carried out at a wide range of current magnitudes and cooling conditions. A good agreement between the temperature measurements and corresponding simulation results is observed. It is demonstrated that using innovative thermally conductive materials in the stator slots and the end winding bodies of liquid-cooled electric machines results in a significant reduction in the winding hot spot temperature. Additionally, the influence of the critical parameters on the impregnation material performance, e. g., impregnation goodness and slot fill factor, is studied.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik -- Reglerteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering -- Control Engineering (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik -- Annan elektroteknik och elektronik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering -- Other Electrical Engineering, Electronic Engineering, Information Engineering (hsv//eng)

Nyckelord

Computational fluid dynamics

direct oil cooling

Epoxylite

hybrid electric vehicle (HEV)

impregnation material

induction machines

lumped parameter (LP) thermal model

silicone-based thermally conductive material (SbTCM)

vacuum impregnation

varnish

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