Inherent Difference in Saliency for Generators with Different PM Materials
Table 2
Electromagnetic characteristics for rated speed and power as well as some geometrical characteristics from stationary simulations for the two generators [2].
Characteristics
G1-Nd
G2-Fe
PM grade
N40H
Y30
Active power (kW)
225
225
Load L-L voltage (V) rms
793
793
Current (A) rms
164
164
Electrical frequency (Hz)
9.9
9.9
Rotational speed (r/min)
33
33
Torque (kNm)
65
65
Cogging (% of rated torque)
1.8
1.3
Electrical efficiency (%)
96.6
96.6
Stator copper losses (kW)
5.4
5.4
Stator iron losses (kW)
2.4
2.4
Load angle (°)
9.6
9.3
Power factor
1
1
Airgap force (MN/m2)
0.18
0.20
Number of poles
36
36
Magnet dimensions (mm)
PM weight
536
4789
Total rotor weight, activea (t)
1.7
8.5
Total rotor weight (t)
3.3
approx. 10.8
Total generator weight, activea (t)
6.5
13.3
Total generator weight (t)
13
approx. 20.5
Active material is material active in the magnetic circuit; see Figure 1.
