Experimental Investigation of Oil Jet Cooling in Electrical Machines With Hairpin Windings

Liu, Chuan; Xu, Zeyuan; Gerada, David; Zhang, Fengyu; Chong, Yew Chuan; Michon, Melanie; Goss, James; Gerada, Chris; Zhang, He

doi:10.1109/tte.2022.3186947

Cited by 15 publications

(2 citation statements)

References 19 publications

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“…In this case, the efficient cooling technique is a significant enabler for improving the performance metrics beyond the current state of the art. Whilst, the implemented temperature reduction is directly beneficial for active material saving and reliability promotion [4,5].…”

Section: Introductionmentioning

confidence: 99%

Heat Pipe Bending Effect on Cooling Effectiveness in Electrical Machines

Zhao

Zhang

et al. 2023

IEEE Trans. Energy Convers.

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Heat pipes (HPs) are being extensively explored in motor cooling scenarios for enhanced cooling capacity. HPs are commonly bent to adapt to the compact structure of electrical machines, whereas the bending effect on motor cooling effectiveness still requires further investigation. This article analytically and experimentally studies the effect of the bending process, including bending angle and bending radius, on HP thermal properties. Cooling density is defined and derived to analyze the tradeoff between HP thermal performance and additional volume due to HP installation. Practical guidelines for feasible HP bending solutions under different space constraints are provided to achieve a higher cooling density. Finally, the HP bending effect on motor cooling effectiveness under various cooling methods is quantitatively evaluated through a validated thermal model based on a stator-winding assembly. The bending process can degrade the HP equivalent thermal conductivity by up to 76%, thus leading to a temperature difference of 4.8K under liquid cooling conditions.

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Section: Introductionmentioning

confidence: 99%

Heat Pipe Bending Effect on Cooling Effectiveness in Electrical Machines

Zhao

Zhang

et al. 2023

IEEE Trans. Energy Convers.

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“…The direct oil impingement cooling of hairpin end-windings has attracted numerous studies in the past few years as a promising cooling approach for EV traction motors. Liu et al [9] analysed the oil jet cooling of hairpin winding using an oil jet distribution bar mounted on top of the end-winding. The oil jet distributor was designed with a series of jet nozzles to impinge oil onto the end-winding.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of Oil Jet Cooling in Electric Traction Motors with Hairpin Windings

Maddumage

Cairns

Paykani

2023

2023 IEEE Workshop on Electrical Machines Design, Control and Diagnosis (WEMDCD)

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Hairpin winding technology, combined with direct oil jet impingement cooling, is a viable solution known to increase volumetric power density and efficiency in the next generation of traction motors. However, the coolant fluid interaction with the complex winding geometry has not yet been fully examined; specifically, with the use of high-fidelity CFD simulations. Thus, the present work investigates the radial and axial oil impinging jets in a hairpin winding motor using multi-phase simulation. The study first analyses power losses and temperature distribution of the motor under the Worldwide Harmonised Light Vehicle Test Procedure (WLTP). Next, the performance of axial and radial jet impingement is numerically analysed by considering the fluid flow. Finally, the two configurations are compared in terms of their oil film formation rate. The results indicate that the maximum power losses observed in typical driving conditions are considerably lower than the maximum losses predicted for the complete operational region of the motor. Moreover, the axial impinging jet shows a higher oil film formation rate compared to a radial jet impingement configuration within the examined conditions.

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