Short-Circuit Characteristics of Superconducting Permanent Magnet Generators for 10 MW Wind Turbines

Abstract

Superconducting permanent magnet generators (SCPMGs) are a potential candidate for 10 MW direct-drive wind turbine applications. This paper presents two 10 MW SCPMG designs using MgB2 cables for the armature winding and investigates the short-circuit characteristics of the designed SCPMGs. The first part of the results shows that the SCPMGs can double the shear stress of a conventional low-speed permanent magnet (PM) generator (from 65 kPa to 130 kPa) whilst avoiding demagnetization of the PMs in rated-load operation. However, the power factor has to drop to a range of 0.7-0.8. The second part of the results shows that during a sudden threephase short circuit, the superconducting armature winding is prone to quench and the PMs are likely to be demagnetized in both proposed designs.

Comparison of AC-Superconducting Multiphase Symmetric-Winding Topologies for Wind Power Generators With PM Rotors

“…Hence, the actual safety margin may comply with a sudden three-phase short circuit. Moreover, according to Liu et al in [30], it is very likely a quench of superconductivity due to a three-phase short circuit for MgB 2 .…”

“…Moreover, a reconsideration of the stacking of SC layers should be done to reduce further the AC losses according to [55]. Additionally, since the reference machine is taken from [29], [30], the terminal voltage is fixed to a specific value, giving the total current and the number of turns per phase. Future work may reconsider the voltage value and number of turns per phase to optimize the superconducting material.…”

“…The reference machine considered in this paper, is taken from Dong Liu et al [29], [30], to size the geometry accordingly for 15 MW. The generator has 48 slots and 40 poles.…”

Co-Design Optimization of Direct Drive PMSGs for Offshore Wind Turbines Based on Wind Speed Profile

“…The slot depth to tooth width ratio is also limited to 8 [24]. Concerning the outer radius R, setting a maximum value is more difficult, especially because the smallest radii do not necessarily lead to the lowest Energies 2021, 14, 4486 8 of 17 masses, here [25]. According to [21], if the external diameter is too large, the stress on the mechanical structure becomes too great.…”

“…Beside the fact that it is an In Table 4, the costs of the four lightest machines presented in Figure 7 are given for comparison. The following material costs were considered [25]: 50 EUR/kg for the magnets, 3 EUR/kg for iron and 15 EUR/kg for copper. As it can be seen, machines optimized considering a MTPA control are less expensive compared to the machines optimized considering an FW control (28% and 18% for q = 3 and q = 5, respectively).…”