铁路机车牵引电机外壳接地方式仿真研究

Simulation Research on Grounding Mode of Traction Motor Shell of Railway Locomotive

对铁路机车牵引电机外壳的两种主要接地方式进行了仿真研究。研究发现,动力线使用非屏蔽线缆,通过第四根电缆使得机壳与牵引变流器连接的接地方式,在理想正弦波激励和含高次谐波的正弦波激励时,开关瞬间均容易产生高频瞬态磁场,轴电流有一个激荡过程,机壳和线缆温升较大;而动力线使用屏蔽线缆,机壳通过与车体最近点连接的接地方式,在理想正弦波激励时,开关瞬间能抑制大部分的高频瞬态磁场,对低频率的磁场抑制较弱,对轴电流的高频部分也能进行缓解,温升较低,但在含高次谐波的正弦波激励情况下,0时刻的瞬态磁场值还是偏高,轴电流也有较大的激荡,温升较高。本文对铁路机车的牵引电机外壳在不同情况下选择合适的接地方式具有参考意义。

The two main grounding methods of railway locomotive traction motor shell were simulated.The study found that the power line uses an unshielded cable,and the fourth cable makes the chassis and the traction converter connected to the grounding mode.When the ideal sine wave excitation and sine wave excitation with higher harmonics are excited,the switching is easy at the instant.A high-frequency transient magnetic field is generated,the shaft current has an oscillating process,and the temperature rise of the chassis and cables is large;while the power line uses shielded cables,the chassis is excited by an ideal sine wave through the grounding method connected to the closest point of the car body.At the moment,the switching moment can suppress most of the high-frequency transient magnetic field,weaker suppression of the low-frequency magnetic field,and can also relieve the high-frequency part of the shaft current.The temperature rise is low,but the sine with higher harmonics.In the case of wave excitation,the value of the transient magnetic field at time 0 is still high,the shaft current also has a large oscillation,and the temperature rise is high.This article has reference significance for choosing proper grounding method of railway locomotive traction motor housing in different situations.