风电变流器直流母线电容器的纹波谐振问题

Ripple Resonance of DC Bus Capacitor of Wind Power Converter

纹波是风电变流器直流侧的一种典型电能质量问题,纹波谐振不仅会影响直流侧的电能质量,严重时还会危及风电系统及其组件的安全稳定运行。介绍了薄膜电容器在风电变流器直流侧中的应用及其实际的等效电路模型;探究了风电变流器直流母线及薄膜电容器的杂散参数对直流侧纹波电流的影响;分析了风电变流器直流侧电容器因纹波谐振而过热损坏的失效机理,并推导出了其固有谐振频率的数学表达式。最后在MATLAB/Simulink中搭建了计及杂散参数的永磁直驱式风电系统仿真模型,仿真结果验证了理论分析和所建模型的正确性。

Ripple is a typical power quality problem on the DC side of wind power converters,ripple resonance not only affects the power quality of the DC side,in severe cases,it will also endanger the safe and stable operation of wind power systems and their components.This paper introduces the application of film capacitors in the DC side of wind power converters and their actual equivalent circuit model;the influence of the stray parameters of the DC bus and film capacitor of the wind power converter on the ripple current on the DC side is investigated;the failure mechanism of the DC side capacitor of the wind power converter due to the ripple resonance is analyzed,the mathematical expression of its natural resonant frequency is derived.Finally,a simulation model of permanent magnet direct-drive wind power system considering stray parameters is built in Matlab/Simulink,the simulation results verify the theoretical analysis and the correctness of the model.