Improved Thermal Management and Analysis for Stator End-Windings of Electrical Machines

Abstract

In electrical machine design, thermal management plays a key role in improving performance and reducing size. End-windings are commonly identified as the machine hot-spot. Hence, lowering and predicting end-windings temperature are crucial tasks in thermal management of electrical machines. This paper proposes and investigates a non-invasive but effective cooling method that aims for a uniform cooling of a machine's winding by implementing direct cooling on its end-windings. Modelling and experimental results show that a 25% hot-spot temperature reduction on a particular application can be achieved. To analyse the proposed technique in detail, an accurate but computationally-economic lumped parameter thermal network is developed. Comparison between a 'standard' thermal network and its simplified equivalent (with less nodes) is presented where the models are developed and fine-tuned based on experimental data. All the above is used to investigate the potential of the proposed end-winding cooling method with different configurations of the methodology.

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“…The operating temperature of a winding is the main cause of the thermal stress, which results from Joule losses plus additional heating due to core eddy currents The associate editor coordinating the review of this manuscript and approving it for publication was Saeid Nahavandi . and hysteresis losses [4], [5]. In insulating materials, this high temperature accelerates chemical reactions involved in the insulation deterioration.…”

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