双馈异步风力发电机的轴电流分析  

Analysis of Bearing Currents in Doubly-Fed Induction Wind Turbines

作　　者：刘瑞芳[1] 任雪娇 陈嘉垚 Liu Ruifang;Ren Xuejiao;Chen Jiayao(School of Electrical Engineering Beijing Jiaotong University Beijing 100044 China)

机构地区：[1]北京交通大学电气工程学院,北京100044

出　　处：《电工技术学报》2018年第19期4517-4525,共9页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金资助项目(51777008)

摘　　要：双馈异步风力发电机是风力发电系统目前广泛采用的形式之一,变流器产生的共模电压通过电机耦合电容形成的共模通路在电机转轴上感应出轴电压并产生轴电流,严重影响风力发电系统的安全稳定运行。建立合理的轴电流分析模型是准确预测轴电流的基础。该文建立了综合考虑定子侧和转子侧共模电压影响的轴电流分析模型,采用电磁场数值计算获得了电机内部杂散电容耦合参数,并给出了多导体系统部分电容的测量方法。针对一台1.5MW双馈异步风力发电机进行分析,结果表明定子侧共模电压的影响可以忽略,可以采用仅考虑转子共模电压作用的简化轴电流模型。同时对轴电压进行了灵敏度分析,指出减小转子绕组和转子铁心之间的杂散电容C_(rwr)能有效减小轴电压,从而抑制轴电流。The common mode voltage caused by the converter can induce bearing voltage through the coupling capacitance and result in the bearing currents,which seriously affect the efficiency and safety of wind power generation.It’s very important to construct a precise bearing currents model.This paper established a completed bearing currents equivalent model,which considered both stator common mode voltage and rotor common mode voltage.The capacitances of the DFIG could be calculated through finite element method and the measurement method on capacitances of DFIG was provided.Then a 1.5 MW DFIG was analyzed.The result showed that bearing voltage induced by stator common mode voltage was very small,and the effects of the stator part can be neglected.The simplified model which only considered the rotor common mode voltage is suitable for analyzing the bearing current problem of DFIG.The sensitivity analysis on capacitors was carried out.The capacitor Crwr is a key parameter to suppress the bearing voltage and bearing current.

关 键 词：双馈异步风力发电机 轴电压 轴电流 耦合电容 轴承分压比 

分 类 号：TM315[电气工程—电机]