基于开关振荡电流的交流电机主绝缘在线监测  

Online monitoring of AC motor grounding insulation based on switch oscillating current

作　　者：李政达 张旭浩 江周余 王梦谦 霍柯 林子棋 LI Zhengda;ZHANG Xuhao;JIANG Zhouyu;WANG Mengqian;HUO Ke;LIN Ziqi(CRRC Qingdao Sifang Rolling Stock Research Institute Co.,Ltd.,Qingdao,Shandong 266000,China;School of Electrical Engineering,Southwest Jiaotong University,Chengdu,Sichuan 610031,China)

机构地区：[1]中车青岛四方车辆研究所有限公司,山东青岛266000 [2]西南交通大学电气工程学院,四川成都610031

出　　处：《机车电传动》2024年第2期126-131,共6页Electric Drive for Locomotives

摘　　要：在变频驱动系统中,由于功率器件高速开关产生的高dv/dt和瞬态过电压,会使电机绝缘部件承受较高的电应力,加速电机绝缘材料的老化,进而增加绝缘故障发生概率并危害驱动系统的整体可靠性。相较于传统的离线监测方法,对电机绝缘状态进行在线监测可以提高监测的实时性并减小停机维修的损失。因此,文章提出一种基于逆变器开关振荡电流的交流电机主绝缘在线监测方法。首先,建立了交流电机绝缘等效电路,分析了绝缘老化对电机阻抗特性的影响,并通过外部并联电容的方法模拟了绝缘老化的过程。然后,采用脉冲宽度调制(PWM),研究了电机主绝缘参数对开关振荡电流的影响,提出了以开关振荡电流频域偏差作为老化特征指标的在线监测方法。试验证明,该方法在不影响电机正常运行的前提下,可以对电机主绝缘老化状态进行有效监测。In the variable frequency drive system,the high dv/dt and transient overvoltage generated by the high-speed switch of the power device will make the motor insulation parts withstand high electrical stress,accelerate the aging of the motor insulation materials,and then increase the probability of insulation failure and harm the overall reliability of the drive system.Compared with the traditional offline monitoring method,online monitoring of motor insulation states can improve the real-time monitoring performance and reduce the loss of shutdown maintenance.Therefore,this paper presents a method of online monitoring of AC motor grounding insulation based on inverter switch oscillating current.First,the authors established an AC motor insulation equivalent circuit,analyzed the influence of insulation aging on the impedance of AC motor,and simulated the insulation aging process by connecting external capacitors in parallel.Then,the influence of the motor grounding insulation parameters on the switch oscillating current under pulse width modulation(PWM)was analyzed,and proposed an online monitoring method with the frequency domain deviation of switch oscillating current as the aging characteristic index.This test shows that this method can effectively monitor the aging state of the motor grounding insulation without affecting the normal operation of the motor.

关 键 词：交流电机 绝缘老化 在线监测 电流响应 逆变器 高速列车 

分 类 号：U292.914[交通运输工程—交通运输规划与管理] TM34[交通运输工程—道路与铁道工程]