Abstract
Given the fact that the operation of electrical machines generates various loss components that finally become heat, developing advanced thermal management technologies is essential to control temperature increases and to guarantee safe operations. Meanwhile, the armature winding can stand larger currents when the machines are equipped with advanced cooling systems, which directly improves torque/power densities. This paper aims to provide a systematic review of the latest developments of advanced thermal management technologies of electrical machines. According to different heat dissipation mechanisms, the cooling systems studied in this paper are categorized into five major types: enclosed housing cooling, enhanced conductive cooling, embedded heat pipe cooling, direct oil cooling, and enhanced rotor cooling. The advantages and disadvantages of these cooling systems are researched and compared comprehensively. This study contributes to the revelation of insights on the thermal management of electrical machines and offers good guidance for the thermal management of electrical machines.