Development and validation of an integrated planetary gear set permanent magnet electric motor power loss model

Nutakor, Charles; Montonen, Juho; Nerg, Janne; Heikkinen, Janne; Sopanen, Jussi; Pyrhönen, Juha

doi:10.1016/j.triboint.2018.03.026

Cited by 14 publications

(9 citation statements)

References 28 publications

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“…The temperature distribution was analyzed in the nominal operating point. The losses caused by oil friction were estimated by applying the calculation scheme presented in [22].…”

Section: Calculation Resultsmentioning

confidence: 99%

“…In the case of an integrated design, the properties and limitations of the planetary gear system have an influence on the electric motor design also because of other physical factors. In this very case, the maximum allowable speed for the planetary gear sun is about 2500 min −1 , because above that speed, the pitch line velocity increases above 10 m/s, resulting in severe lubricating oil whip, which leads to difficulties in circulating the cooling and lubricating oil [22]. Therefore, the rated speed of the electrical motor is chosen to be about half of that speed at 1200 min −1 , enabling about 50% field weakening for the motor at the 2400 min −1 maximum speed.…”

Section: Electromagnetic Analysismentioning

confidence: 99%

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Integration Principles and Thermal Analysis of an Oil-Cooled and -Lubricated Permanent Magnet Motor Planetary Gearbox Drive System

et al. 2019

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A permanent magnet traction motor integrated with a planetary gearbox is studied. A machine of this kind can be employed as a propulsion motor in off-road machines like agricultural tractors that have to produce either very high traction forces at low speeds or reach higher traveling speeds at lower torques. In principle, a constant power curve as a function of speed is desired, which means that the output torque of the drive system should be inversely proportional to the operating speed of the off-road machine. Such driving conditions are challenging as the electric motor has to be heavily overloaded at the lowest speeds. Therefore, it is essential to accurately evaluate not only the electromagnetic performance but also the thermal performance of the machine. This paper studies the integration principles of an electrical machine and a planetary gear. The integration poses some new challenges to the design. For example, also the lubrication and cooling can, and, in practice, must be integrated into the system. The thermal performance of the motor and cooling with the lubrication oil of the gear were analyzed. The long-term tests with the oil cooling system were carried out to verify the successful integration.

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“…The temperature distribution was analyzed in the nominal operating point. The losses caused by oil friction were estimated by applying the calculation scheme presented in [22].…”

Section: Calculation Resultsmentioning

confidence: 99%

Section: Electromagnetic Analysismentioning

confidence: 99%

Integration Principles and Thermal Analysis of an Oil-Cooled and -Lubricated Permanent Magnet Motor Planetary Gearbox Drive System

et al. 2019

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“…Sliding friction (characterized by the thin film and high viscosity at the Hertzian region of the EHD contact) increases the bulk temperature; in addition, it generates friction forces that contribute to energy losses. In regard to gearbox efficiency, the product of the traction force and the rate of slip at a rolling‐sliding contact is a direct measure of the sliding mechanical power loss at the rolling element bearing and race contact and also at the gear mesh contact …”

Section: Introductionmentioning

confidence: 99%

“…In regard to gearbox efficiency, the product of the traction force and the rate of slip at a rolling-sliding contact is a direct measure of the sliding mechanical power loss at the rolling element bearing and race contact 16 and also at the gear mesh contact. [17][18][19][20] Although wind turbine gearboxes tend to fail predominately at critical bearing locations because of white structure flaking (WSF), 2 several recent studies on wind turbine gearbox rolling element bearings have shown that lubrication conditions can also have an impact on rolling contact fatigue (RCF). [21][22][23] Similarly, it has been shown elsewhere that the boundary and mixed lubrication regimes together with frictional energy should be used as key input parameters in tribological experiments that aim to reproduce actual service operating conditions that initiate WSF.…”

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confidence: 99%

An experimental characterization of the friction coefficient of a wind turbine gearbox lubricant

2019

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In this study, a method to predict the contact friction coefficients at the rolling‐sliding contacts of isotropic superfinished and axially ground gear and bearing surfaces in wind turbine gearboxes is proposed. A two‐disc test rig was used to measure friction coefficient values within a slide‐to‐roll ratio range of −0.8 to 0.8, rolling velocities of 2 to 12 m/s, at oil temperatures of 50°C, 70°C, and 100°C and Hertzian contact pressures of 1.2, 1.6, and 2.0 GPa. A polyalphaolefin (PAO) International Standards Organization (ISO) viscosity grade (VG) 320 was the lubricant. Data from 90 individual friction coefficient tests were combined to develop two closed‐form friction coefficient formulae. A multivariable linear regression analysis was used to derive the regressed formulae. Using the developed regressed formulae, the predicted friction values follow the trend of measured values at all of the operating conditions. The results show that the regressed formulae are close to experimental friction coefficient values. The friction coefficient predictions confirm that the regressed formulae are capable of simulating contact friction values for the lubricated contact conditions considered.

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“…Also different kinds of magnetic gear solution are studied in [9]- [11] but a mechanical gear was selected in this analysis because of its low price, large torque tolerance and robustness. It is often stated that a mechanical gear has lots of losses but different authors have shown with several measurements in [12] that the selected two step planetary gear has low losses.…”

Section: Introductionmentioning

confidence: 99%

A New Traction Motor System With Integrated-Gear: A Solution for Off-Road Machinery

et al. 2019

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Off-road traction applications require extremely high torque, especially, at low speeds. Such a high torque can be reached by gearing up the torque of an electrical machine. A tooth-coil permanent magnet synchronous machine with an integrated planetary gear is proposed as a solution for heavy off-and on-road traction applications. The key benefits of tooth-coil permanent-magnet synchronous machine (PMSM) in the proposed drive system and its integration with a planetary gearbox are explained in detail. A multiobjective optimization is performed to determine the slot/pole combination of the PMSM and the design process of the proposed drive system is entirely clarified. The proposed tooth-coil PMSM is investigated by electromagnetic and structural finite element analysis to obtain the final design and highlight the machine performance. A prototype is built to validate the proposed system. The results show that the traction drive system works well in laboratory and offers means to serve as a traction system in heavy off-and on-road applications. INDEX TERMS Permanent magnet machines, traction motors, torque, planetary gear.

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Development and validation of an integrated planetary gear set permanent magnet electric motor power loss model

Cited by 14 publications

References 28 publications

Integration Principles and Thermal Analysis of an Oil-Cooled and -Lubricated Permanent Magnet Motor Planetary Gearbox Drive System

Integration Principles and Thermal Analysis of an Oil-Cooled and -Lubricated Permanent Magnet Motor Planetary Gearbox Drive System

An experimental characterization of the friction coefficient of a wind turbine gearbox lubricant

A New Traction Motor System With Integrated-Gear: A Solution for Off-Road Machinery

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