Influences of Design and Manufacturing on the Performance of Electric Traction Drives

Halwas, Maximilian; Hausmann, Ludwig; Wirth, Felix; Fleischer, Jürgen; Jux, Benedict; Doppelbauer, Martin

doi:10.1109/icem49940.2020.9270899

Cited by 18 publications

(3 citation statements)

References 42 publications

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“…The subconductor insulation consists either of a polymer varnish or, as shown in Fig. 2b, of thin mica tapes or foils with which the subconductor is wound [19], [23], [51]. Mica is a naturally occurring inorganic material that is characterized by its high resilience to PDs and it prevents the erosion effect of PD [52], [53].…”

Section: B Electrical Insulation System and Materials Of LV And Hv Ma...mentioning

confidence: 99%

The Insulation Resilience of Inverter-Fed Low Voltage Traction Machines: Review, Challenges, and Opportunities

2022

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The use of wide bandgap (WBG) semiconductor devices, which enable higher switching slew rates, and the increase in DC link voltage, which provides system-wide advantages, exposes the winding system of traction machines to enhanced electrical stress. The resulting nonlinear voltage distribution along the motor winding favors partial discharges (PD), which in low voltage (LV) machines causes excessive damage to the insulation system, and premature failure can occur. A simple solution by increasing the enamel thickness of the wires leads on the one hand to a lower copper fill factor. On the other hand, this measure is not necessarily accompanied by an increase in electrical resilience in the case of pulsed voltage. It is therefore essential to understand the phenomenon of partial discharges, which is composed of a large number of processes and mechanisms, to be able to make an estimation of aging. The ultimate goal is to derive a lifetime model that links the dynamic load collectives -ideally in conjunction with the environmental stress influences -of a traction application to a usage-dependent and realistic prediction of the residual lifetime. To this end, this paper provides an overview of the current state of science and technology in this interdisciplinary topic by describing, with reference to high voltage (HV) technology/engineering, the design of the insulation system, the discharge physics, the degradation mechanisms, the statistical effects to be considered, and the partial discharge measurement methods.

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Section: B Electrical Insulation System and Materials Of LV And Hv Ma...mentioning

confidence: 99%

The Insulation Resilience of Inverter-Fed Low Voltage Traction Machines: Review, Challenges, and Opportunities

2022

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“…The generation of this magnetic field is facilitated by copper wires within the stator slot [1]. The limitations on the magnetic field due to shape factor constraints addressed through the use of hairpin coils, which is characterized by a rectangular cross-sectional geometry [2], [3], [4]. Hairpin coils help mitigate the impact of the stator slot geometry by minimizing empty space while simultaneously enhancing the winding number and magnetic field strength, as shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Mechanical Properties Considering Uncertainties for Hairpin Coils in Electric Vehicle Motor Manufacturing

Shim,

Kim,

Kim

et al. 2024

IEEE Access

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The rising demand for electric vehicles (EVs) underscores the need for enhancing electric motor efficiency. Utilizing hairpin coils with a rectangular cross-section has emerged as an alternative approach to increase conductor density in motor stator slots. However, the manufacturing process for hairpin coil motors presents challenges such as springback, which stems from wire shaping processes such as leveling and bending with plastic deformation. These challenges are closely tied to mechanical properties of the Young's modulus and yield stress. This study investigates uncertainties in mechanical property evaluation using a combination of tensile tests, analytic solutions, numerical simulations, and a present double-sided four-point bending method. The results show significant variations in the Young's modulus, which affect the determination of yield stress in tensile tests. It has been revealed that in order to obtain stable mechanical properties of hairpin coils in tensile tests, the conditions should be restricted to a very slow strain rate, slower than 10 -3 s -1 . To address this, this study introduces an alternative method that combines double-sided four-point bending and tensile tests, allowing for the acquisition of Young's modulus without prior information on material properties. This approach reduces uncertainties in determination of the mechanical properties with much less time cost.

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“…The fill factor indicates the ratio of the conductor area to the available slot area in the stator sheet metal package. [1,2] The compaction process step is part of the compact winding process, which has been developed at the wbk Institute of Production Science in previous research work [3]. In this context, compaction refers to two process steps: The first is the compression step, which compacts the winding without significant plastic deformation, the second is the forming step with a high degree of plastic deformation.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Forming Behavior of Copper Wires for the Compaction of Windings for Electric Machines

Halwas

Wirth

Fleischer

2022

KEM

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To meet the increasing demand for highly efficient electric traction drives, the compact winding process has been developed at the wbk Institute of Production Science. One key element of the process chain is the compaction of the round wire stator windings. In order to enable an estimation of the sensitivities of the influencing factors, a simplified finite element simulation model was set up in the present work. In the calculations, the number of wire layers, the layer structure and the punch stroke were selected as factors with three levels each. The evaluation was performed by means of false color images and the maximum strains and stresses in the section plane of the slots.

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Influences of Design and Manufacturing on the Performance of Electric Traction Drives

Cited by 18 publications

References 42 publications

The Insulation Resilience of Inverter-Fed Low Voltage Traction Machines: Review, Challenges, and Opportunities

The Insulation Resilience of Inverter-Fed Low Voltage Traction Machines: Review, Challenges, and Opportunities

Evaluation of Mechanical Properties Considering Uncertainties for Hairpin Coils in Electric Vehicle Motor Manufacturing

Investigation of the Forming Behavior of Copper Wires for the Compaction of Windings for Electric Machines

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