表贴式与内置式永磁同步风力发电机的轴电流模型对比分析

摘要

Permanent magnet synchronous generators (PMSG) are connected to the grid through converters.The common mode voltage from the converter could induce the high bearing voltage and bearing currents,which endangers the safety of the operation system.It is important to analyze the bearing current problem of PMSGs.The circuit models of bearing currents in surface mounted PMSG and built-in PMSG are put forward in this paper.The coupling capacitances are obtained through analytical calculation and bearing voltage ratios are determined.According to the analysis of the two types of PMSG,it shows that bearing voltage ratio of the PMSG is smaller than the double fed induction generator (DFIG).The bearing voltage ratio of built-in PMSG is close to the surface mounted PMSG,but the common mode current in surface mounted PMSG is bigger than which in built-in PMSG.%永磁同步风力发电机通过变流器与电网相连时,变流器产生的共模电压会产生轴电压和轴电流,继而引起轴承早期失效,危害系统的安全运行,因此对永磁同步风力发电机轴电流问题进行研究具有重要意义.本文对表贴式与内置式永磁同步发电机的轴电流问题进行分析,分别建立轴电流分析模型,通过解析计算获取杂散电容参数,确定发电机的轴承分压比.通过对比分析发现:永磁同步发电机的轴承分压比小于双馈异步发电机;内置式永磁同步风力发电机与表贴式的轴电压分压比相近;但是表贴式永磁同步电机的共模电流较大.