Analytical Thermal Model of Natural-Convection Cooling in Axial Flux Machines

Abstract

An analytical approach is proposed in developing a lumped parameter thermal model for the stator coils of naturally-cooled Axial-Flux Tooth-Coil Permanent-Magnet Machines. The model comprises one tooth, the coil around it, the air channels between coils and the teeth supporting structure; each component is subdivided into cuboidal or arc sub-elements. An expression of the convective exchange coefficient is proposed to take into account the radial position of each tooth. Experimental results validate the proposed model, which can also be used in the design stage of a machine.

Influence of Complex Fluid Flow on Temperature Distribution in the Rotor Region of Large Hydrogenerator Under the Rotor Rotation

“…The rotor rotation of the hydrogenerator is considered. After solving the fluid and thermal equations of fluid-solid conjugated heat transfer, fluid velocity and temperature distribution are obtained in the rotor region of hydrogenerator [22]- [27]. The influence of fluid velocity in the different directions on the temperature of the rotor excitation winding is studied under the different flow rates in the hydrogenerator rotor region.…”

An overview of thermal modelling techniques for permanent magnet machines

“…The theory and required calculations to design the insulation and cooling system of a PM generator using thermal analysis have been presented in [132]. Thermal analysis and optimization of the cooling system are one of the key steps in design of electrical machines, therefore, a wide array of cooling options such as cooling with air [38,133], oil [134][135][136], or water [137], and also natural [133] and forced [38,[134][135][136][137] cooling layouts has been studied.…”

Insulation Capacitance as Diagnostic Marker for Thermally Aged, Low Voltage Electrical Machines

“…According to the Arrhenius law for thermally-activated chemical reactions, the lifetime of a solid insulating material is directly related to its absolute temperature through an exponential relationship [16]. It is then clear that improved thermal management [17,18] and modeling [19,20], as well as thermal lifetime assessment and prediction [21,22] are of primary importance in the EMs design process. The aforementioned aspects are nowadays relevant more than ever, especially for high performance EMs employed in safety-critical applications such as aerospace actuators [23,24], where high level of reliability and fault-tolerance capabilities are a main requirement [25,26].…”