Author Contributions
Conceptualization, M.C., Z.L. and S.X.; methodology, M.C.; software, Z.L.; validation, M.C., Z.L. and S.X.; formal analysis, Z.L.; investigation, S.X.; resources, R.P.; data curation, M.C.; writing—original draft preparation, M.C.; writing—review and editing, Z.L. and S.X.; visualization, S.X.; supervision, M.C.; project administration, S.X.; funding acquisition, R.P. All authors have read and agreed to the published version of the manuscript.
Figure 1.
Cross-section of UHSPMM.
Figure 1.
Cross-section of UHSPMM.
Figure 2.
Loss distribution of iron core.
Figure 2.
Loss distribution of iron core.
Figure 3.
Calculation of wind friction loss: (a) air flow velocity distribution; (b) wind friction loss under different speeds.
Figure 3.
Calculation of wind friction loss: (a) air flow velocity distribution; (b) wind friction loss under different speeds.
Figure 4.
Eddy current density distribution.
Figure 4.
Eddy current density distribution.
Figure 5.
Thermal analysis model.
Figure 5.
Thermal analysis model.
Figure 6.
Computational fluid dynamics results at 95 krpm and 25 kW: (a) pressure distribution of water jacket; (b) temperature distribution of water jacket.
Figure 6.
Computational fluid dynamics results at 95 krpm and 25 kW: (a) pressure distribution of water jacket; (b) temperature distribution of water jacket.
Figure 7.
Temperature distribution at 95 krpm and 25 kW: (a) winding temperature; (b) rotor temperature.
Figure 7.
Temperature distribution at 95 krpm and 25 kW: (a) winding temperature; (b) rotor temperature.
Figure 8.
Rotor structure of the UHSPMM: (a) rotor structure dimensions; (b) force diagram of PM; (c) force diagram of sleeve.
Figure 8.
Rotor structure of the UHSPMM: (a) rotor structure dimensions; (b) force diagram of PM; (c) force diagram of sleeve.
Figure 9.
Sleeve stress distributions (T = 22 °C, n = 95 krpm): (a) 2D; (b) 3D.
Figure 9.
Sleeve stress distributions (T = 22 °C, n = 95 krpm): (a) 2D; (b) 3D.
Figure 10.
Variation of rotor stresses with operating speed.
Figure 10.
Variation of rotor stresses with operating speed.
Figure 11.
PM tangential stress distributions with different operating speeds (T = 22 °C): (a) n = 95 krpm; (b) n = 110 krpm.
Figure 11.
PM tangential stress distributions with different operating speeds (T = 22 °C): (a) n = 95 krpm; (b) n = 110 krpm.
Figure 12.
PM tangential stress distributions with different operating speeds (T = 180 °C): (a) n = 95 krpm; (b) n = 110 krpm.
Figure 12.
PM tangential stress distributions with different operating speeds (T = 180 °C): (a) n = 95 krpm; (b) n = 110 krpm.
Figure 13.
Sleeve equivalent stress distributions with different operating speeds (T = 180 °C): (a) n = 95 krpm; (b) n = 110 krpm.
Figure 13.
Sleeve equivalent stress distributions with different operating speeds (T = 180 °C): (a) n = 95 krpm; (b) n = 110 krpm.
Figure 14.
Maximum sleeve stress and PM maximum tangential stress versus the sleeve thickness: (a) maximum sleeve stress; (b) PM maximum tangential stress.
Figure 14.
Maximum sleeve stress and PM maximum tangential stress versus the sleeve thickness: (a) maximum sleeve stress; (b) PM maximum tangential stress.
Figure 15.
Sleeve, PM maximum stress variations with interference for 3 mm thickness sleeve: (a) maximum sleeve stress; (b) PM maximum tangential stress.
Figure 15.
Sleeve, PM maximum stress variations with interference for 3 mm thickness sleeve: (a) maximum sleeve stress; (b) PM maximum tangential stress.
Figure 16.
Sleeve, PM maximum stress variations with temperature: (a) PM tangential stress; (b) sleeve equivalent stress.
Figure 16.
Sleeve, PM maximum stress variations with temperature: (a) PM tangential stress; (b) sleeve equivalent stress.
Figure 17.
UHSPMM rotor with Solid PM.
Figure 17.
UHSPMM rotor with Solid PM.
Figure 18.
Campbell diagram of UHSPMM rotor.
Figure 18.
Campbell diagram of UHSPMM rotor.
Figure 19.
Calculated results of mode shape for UHSPMM rotor: (a) 12,753 rpm; (b) 18,054 rpm; (c) 173,140 rpm.
Figure 19.
Calculated results of mode shape for UHSPMM rotor: (a) 12,753 rpm; (b) 18,054 rpm; (c) 173,140 rpm.
Figure 20.
UHSPMM prototype: (a) rotor; (b) stator.
Figure 20.
UHSPMM prototype: (a) rotor; (b) stator.
Figure 21.
Back EMF experimental and calculated results with UHSPMM prototype speed.
Figure 21.
Back EMF experimental and calculated results with UHSPMM prototype speed.
Figure 22.
Power loss experimental results for UHSPMM prototype.
Figure 22.
Power loss experimental results for UHSPMM prototype.
Figure 23.
No-load current and casing vibration under different speed. (a) No-load input current; (b) vibration velocity.
Figure 23.
No-load current and casing vibration under different speed. (a) No-load input current; (b) vibration velocity.
Figure 24.
Wind friction loss comparison of calculation and measurement at different speeds.
Figure 24.
Wind friction loss comparison of calculation and measurement at different speeds.
Figure 25.
Measured winding temperatures under load operation.
Figure 25.
Measured winding temperatures under load operation.
Table 1.
Main design of UHSPMM.
Table 1.
Main design of UHSPMM.
Parameters | Value | Parameters | Value |
---|
Rated power | 25 kW | Rated speed | 95,000 rpm |
Stator outer diameter | 100 mm | Extreme speed | 110,000 rpm |
Stator slot number | 24 | Rotor outer diameter | 39 mm |
Stator inner diameter | 45 mm | Pole pair number | 2 |
Slot opening width | 2 mm | Pole arc pole pitch | 1 |
Winding Connection | Y | PM material | Sm2Co17 |
Winding layer number | 2 | PM thickness | 16.5 mm |
Iron core length | 56 mm | Sleeve thickness | 3 mm |
Conductors per slot | 12 | PM conductivity | 110,000 S/m |
Phase number | 3 | Sleeve conductivity | 610,000 S/m |
Table 2.
Rotor eddy current loss.
Table 2.
Rotor eddy current loss.
| No Load | Rated Load |
---|
| 2D | 3D | 2D | 3D |
---|
Sleeve (W) | 32.86 | 31.23 | 154.19 | 147.69 |
PM (W) | 0.51 | 0.49 | 23.8 | 22.67 |
Total (W) | 33.37 | 31.72 | 177.99 | 170.36 |
Table 3.
Loss distribution of UHSPMM.
Table 3.
Loss distribution of UHSPMM.
| Stator Iron Loss | Copper Loss | Wind Frictional Loss | PM Eddy Current Loss | Sleeve Eddy Current Loss |
---|
Loss (W) | 371.42 | 240.3 | 95.3 | 23.8 | 154.8 |
Table 4.
Material mechanical properties.
Table 4.
Material mechanical properties.
| Inconel 718 | Sm2Co17 |
---|
Density (kg/m3) | 8190 | 8400 |
Coefficient of thermal expansion (1/K) | 13 10−6 | 9 10−6 |
Young’s Modulus (GPa) | 211 | 151 |
Yield strength (MPa) | 1036 | 42 (tensile) 900 (compressive) |
Poisson’s ratio | 0.27 | 0.294 |
Table 5.
UHSPMM maximum stress results.
Table 5.
UHSPMM maximum stress results.
| Sleeve | PM |
---|
| (MPa) | Radial (MPa) | Tangential (MPa) |
---|
A | 906.39 | −95.01 | −13.17 |
B | 772.44 | −74.67 | 7.14 |
C | 830.24 | −56.77 | 40.74 |
Table 6.
Temperature results by CFD and measurement.
Table 6.
Temperature results by CFD and measurement.
| CFD | Measurement |
---|
Winding (°C) | 104.5 | 108.3 |
Rotor surface (°C) | 175.4 | 169.2 |