High-power density induction machines with increased windings temperature

Abstract

The increase of the operating temperature of electrical machines is a major challenge in the context of the large-scale use of electricity in many industrial or individual applications such as mobility. Indeed, working at higher temperatures makes it possible to place electrical actuators in critical areas – such as aircraft engines, for example – and/or to significantly improve the power-to-weight ratio of the machine. For several applications (deep pumping, ventilation, etc.), the use of the induction machine is still preferred due to cost, simplicity and robustness essentially. The objective of this study is to estimate the possibilities of making a high-temperature squirrel cage induction machine. A significant increase in the operating temperature of a machine would indirectly allow us to envisage an increase in the current density in the active conductors and thus a significant improvement in the power-to-weight ratio. However, this is at the sacrifice of efficiency. The aim of this study is to evaluate this decrease in efficiency correlated with the increase in the temperature to find the best compromise according to the relevant applications. An analytic sizing model has been proposed for the prediction of losses, which will be coupled with a thermal model to predict the temperature in different parts of the machine. This study presents essential information on the influence of temperature on the parameters important for the performance of an induction machine.

Keywords

• induction machine
• high temperature
• current density
• power-to-weight ratio
• machine efficiency