A New End Windings Transposition to Reduce Windings Eddy Loss for 2 MW Direct Drive Multi-Unit PMSM

The additional eddy loss in the solid strand of the formed coil is an important part of windings copper loss in the superpower direct drive permanent magnetic synchronous motor (PMSM). This eddy loss produces due to the uneven leakage magnetic field in the stator slot region. The traditional windings transposition technology is difficultly applied to the multi-turn and less-strand formed coil, because of the limited slot fill factor. Therefore, aiming to reduce the additional eddy loss, this paper proposes a new end windings transposition technology and it was used in a 2 MW low-speed and high-torque multi-unit PMSM prototype. The additional eddy loss inhibitory excellent effect is verified by finite element analysis. It should be emphasized that this technology can be directly used in the permanent magnetic direct drive wind generator.