Optimal Sizing of Hairpin Conductors in highway operation with PWM power supply

Notari, Riccardo; Devito, Giampaolo; Bernardi, Fabio; Pastura, Marco; Barater, Davide; Nuzzo, Stefano

doi:10.1109/wemdcd55819.2023.10110896

Cited by 1 publication

(1 citation statement)

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“…A greater copper fill factor enhances a better utilisation of the available space, potentially resulting in improved motor efficiency and performance. All these aspects are well discussed in [6], which also analyses the possibility of adopting a variable cross-section of conductors to reduce the AC losses (Figure 1c). In particular, due to their large cross-section, hairpins suffer high AC losses at high frequencies, primarily due to skin and proximity effects.…”

Section: Introductionmentioning

confidence: 99%

Investigation on the Torsional–Flexural Instability Phenomena during the Bending Process of Hairpin Windings: Experimental Tests and FE Model Validation

Mangeruga,

Barbieri,

Giacopini

et al. 2024

Machines

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Modern electric motors developed for the automotive industry have an ever higher power density with a relatively compact size. Among the various existing solutions to improve torque and power density, a reduction in the dimensions of the end-windings has been explored, aiming to decrease volume, weight, and losses. However, more compact end-windings often lead to complex shapes of the conductors, especially when preformed hairpin windings are considered. The rectangular cross-section of hairpin conductors makes them prone to deviating out of the bending plane during the forming process. This phenomenon, known as torsional–flexural instability, is influenced by the specific aspect ratio of the cross-section dimensions and the bending direction. This study focuses on understanding this instability phenomenon, aiming to identify a potential threshold of the cross-section aspect ratio. The instability makes it difficult to predict the final geometry, potentially compromising the compliance with the geometric tolerances. A finite element model is developed to analyse a single planar bend in a hairpin conductor. Various cross-section dimensions with different aspect ratios are simulated identifying those that experience instability. Moreover, an experimental campaign is conducted to confirm the occurrence of instability by testing the same single planar bending. The experimental data obtained are used to validate the finite element model for the tested dimensions. The aim is to provide designers with a useful tool to select hairpin geometries that are more suitable for the folding process, contributing to successful assembly and improving the overall design process of preformed hairpin conductors.

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Section: Introductionmentioning

confidence: 99%