大功率储能变流器功率模组DC-link电容器的试验研究

Experimental Research on DC-link Capacitor of Power Modules in High-power Energy Storage Converter

从满足最恶劣运行工况下纹波电流和满足动态响应的电容容值这两方面,对三相大功率储能变流器功率模组中的DC-link电容进行了计算设计。在简化模型下,定性分析了功率模组间连接铜排寄生电感对电容纹波电流的放大效应,并采取实验验证的方式在整机装置上进行了测试验证。测试发现,模组采用铜排连接方式的原有设计不合理,电容纹波电流放大明显,不能满足设计要求。针对该问题进行了改良设计,模组间更换采用叠排方式连接,改进后模组内DC-link电容的纹波电流放大现象得到了明显抑制,满足整机设计要求。

From the aspects of satisfying the ripple current in the worst operating conditions and satisfying the capacitance capacity under the dynamic response,the DC-link capacitor of power modules in a three-phase high-power energy storage converter was calculated and designed.In the simplified model,the amplification effect of the parasitic inductance of copper bars connected between power modules on the capacitor ripple current was qualitatively analyzed,and the test verification was carried out on the whole device,showing that the original design of modules connected by copper bars was unreasonable,and the capacitor ripple current amplification obviously cannot meet the design requirements.To solve this problem,the original design was improved,i.e.,the connection between modules was replaced by a stacking mode.As a result,the ripple current amplification phenomenon of the DC-link capacitor in the modules after improvement was significantly suppressed,which satisfied the design requirements of the whole machine.