| 1. |
- Boscaglia, Luca, 1991, et al.
(författare)
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Convective Heat Transfer Coefficients and Mechanical Loss Evaluation of Oil Splashing in Direct Cooled Electrically Excited Hairpin Motors
- 2022
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Ingår i: 2022 International Conference on Electrical Machines, ICEM 2022. ; , s. 496-503
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Konferensbidrag (refereegranskat)abstract
- There in an increasing trend in the use of the direct oil cooling in electric motors for automotive because of the increasing demand of high power/torque density as well as overload capability. One of the most immediate solution is to fill the housing with some oil level and benefit of the heat transfer from the oil splashing. The mechanical losses coming from the rotor rotation are well known and they represent a significant challenge, especially at high speed and high oil level. Therefore, the derivation and prediction of these losses have not been properly investigated leading to a lack in the current literature. Moving Particles Simulation (MPS) method is used in Particleworks to calculate the mechanical losses caused by the oil viscosity and convective heat transfer coefficients (HTC) are extracted for a 250 kW Electrically Excited Synchronous Machine at different speeds and oil levels.
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| 2. |
- Tang, Junfei, 1990, et al.
(författare)
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Observations of Field Current and Field Winding Temperature in Electrically Excited Synchronous Machines with Brushless Excitation
- 2022
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Ingår i: 2022 International Conference on Electrical Machines, ICEM 2022. ; , s. 841-847
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Konferensbidrag (refereegranskat)abstract
- Electrically excited synchronous machines have become an alternative in electrification of transportations and renewable power generations. To reduce the extra effort in the maintenance of sliprings and brushes for field excitation, brushless excitation has been developed. However, when brushless excitation is adopted, the field winding becomes physically inaccessible when the machine is rotating. To solve this problem, an algorithm is proposed in this study to observe the field current and field winding temperature of an EESM with brushless excitation. The stator currents are measured and then used to correct the machine state predictor. The correction of the state prediction is interpreted to adjust the field winding resistance and temperature value. The algorithm is evaluated in simulations. The estimations of field current and field winding temperature track the measurements successfully.
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