感应牵引电机定子绕组涡流附加损耗分析

Analysis of Eddy Current Additional Loss in Induction TractionMotor Stator Winding

高功率密度感应牵引电机具有结构紧凑、磁通饱和度高、工作频率高、单位体积损耗密度大等特点。高工作频率导致定子绕组趋肤效应和邻近效应明显增加,在定子绕组中感应高频涡流附加损耗,引起附加铜耗大大增加。基于感应电机内部谐波磁场理论分析定子绕组涡流附加损耗的来源、计算方法及影响因素,并对一款4极650 kW感应牵引电机进行了详细有限元分析。分析了感应牵引电机定子槽内磁场分布、槽内磁场的各次谐波、谐波幅值与距槽口深度的关系,并计算了槽内导体的涡流附加损耗。计算结果表明槽口附近导体的涡流附加损耗最大,随着距离槽口深度的增加,槽内导体的涡流附加损耗呈明显减小的趋势,通过合理设计定子槽口深度可以有效减小槽口附近导体的涡流附加损耗。

High-power-density induction traction motors have the characteristics of compact structure,high magnetic flux saturation,high operating frequency and high volume loss density.The high operating frequency leads to the significant increase of skin effect and proximity effect of the stator windings.The high frequency eddy current additional loss is generated in the stator windings,causing additional copper loss to increase greatly.Based on the internal harmonic magnetic field theory of the induction motor,the source,calculation method and influencing factors of the stator windings eddy current additional loss are analyzed.A 4-pole 650 kW induction traction motor is analyzed in detail with the finite element method.The stator slot inner magnetic field distribution,the harmonics of the magnetic field in the slot,and the relationship between harmonic amplitude and depth from slot opening are analyzed,and the eddy current additional loss of conductors in the slot is calculated.The calculation results show that the eddy current additional loss of the conductors near the slot opening is the largest,and as the depth from the slot opening increases,the eddy current additional loss of conductors in the slot shows a significant reduction trend.By reasonable design of the stator slot opening depth,the eddy current additional loss of the conductors near the slot opening can be effectively reduced.