风机中参数变化对变流器直流侧电容可靠性的影响分析

Effects of wind turbine parameters on reliability of DC-link capacitor in power converter

以风电机组功率变流器可靠性评估为背景,给出了一种直流侧电容的可靠性评估方法。基于电容的损耗计算方法,结合热网络结构,构建了直流侧电容的可靠性分析流程。综合考虑电容的可靠性影响因素,分析了环境温度、风速、电容等效串联电阻及热阻的变化对直流侧电容可靠性的影响。以某风电场2 MW双馈风电机组结合实际风速、气温数据为例进行验证,实例结果验证了理论分析的正确性。讨论了当风电变流器实际工作时,利用优化变流器直流侧设计或电容的散热环境等措施提高直流侧电容的可靠性,结果表明了所提方案的可行性。

With the background of reliability evaluation in wind turbine power converter,a reliability evaluation method for DC-link capacitor is proposed.Based on the loss calculation of capacitor,the flowchart for reliability analysis of DC-link capacitor combined with the thermal network model is investigated.Considering the influence factors of the capacitor reliability,the influence of the ambient temperature,wind speed,equivalent series resistance of capacitor and thermal resistance on the reliability of DC-link capacitor are discussed.Taking a 2 MW DFIG（Doubly-Fed Induction Generator）-based wind farm as an example and combining with the real wind speed and air temperature profiles,the results verify the correctness of theoretical analysis.The measures to improve the reliability of the DC-link capacitor through optimizing the DC-link design or thermal dissipated condition are discussed in view of actual work condition of wind power converter,and the results show the feasibility of the proposed scheme.