Thermal-Flow Performance of Stator Ventilation Structure Featuring Z-Shape Channels in Permanent Magnet Synchronous Wind Generators

The elevation in power density of permanent magnet synchronous wind generators (PMSWGs) is constrained by the thermal conditions of its windings and magnets. In conventional radial ventilation structure, the stator core is completely divided into multiple substacks, which form radial channels between each other. This leads to an increase in the axial length and a reduction in power density of the generator. This paper proposes a stator ventilation structure characterized by Z-shape channels. The Z-shape channels are formed by stacking three different shapes of lamination sheets without dividing the stator core. The flow and temperature fields of 3.2 MW PMSWGs with different ventilation structures are analyzed in detail using computational fluid dynamics (CFD) methods. Owing to larger specific surface area, higher convection heat transfer coefficient and lower pressure loss, the proposed structure provides better cooling and ventilation performance compared to radial ventilation structure. Under the same cooling fan power and temperature rise limit, the winding current and the generator output power can be increased by 9.31% and 8.07%, respectively. Finally, experimental validations are implemented on small-scale prototypes.