Influence of magnetic slot wedge on the performance of 10-kV, 1000-kW permanent magnet synchronous motor

摘要

Because of uneven air-gap magnetic field caused by open slots in stator cores, motor performance is influenced by harmonic magnetic field in air-gap. In this paper, a 10-kV, 1000-kW line-start high-voltage permanent magnet synchronous motor (LS-HV-PMSM) is taken as an example to establish finite element models when the magnetic slot wedge relative permeability is different. The influence of using the magnetic slot wedge on a motor's torque ripple, loss, and starting performance is studied. On the basis of the analysis of the torque ripple coefficient, the influence of the magnetic slot wedge relative permeability on torque ripple is obtained. Using the finite element method, the influence of the magnetic slot wedge relative permeability on a motor's loss is studied. It is found that the rotor cage bar eddy-current loss is changed obviously. The relationship between the rotor cage bar eddy-current loss and rotor cage bar current density is determined. Furthermore, the influence mechanism of rotor cage bar current density on rotor cage bar eddy-current loss is revealed. According to the speed change curve, the starting performance of the LS-HV-PMSM is analyzed, and the influence of slot leakage reactance on a motor's starting performance is obtained. On the basis of the above analysis, some references are obtained for choosing the magnetic slot wedge with suitable relative permeability when the LS-HV-PMSM is designed.