This paper presents a method for improving the reliability of DC nanogrids by decreasing the input capacitance requirement. The nanogrid DC bus capacitance requirement is reduced by utilizing the zero-sequence operation mode of the solid state converter (SSC). This SSC is often considered as the main DC nanogrid energy control unit that is linking the nanogrid with the main utility AC grid and managing the nanogrid elements. The proposed method injects a zero-sequence voltage in the SSC AC filter capacitors to compensate the low frequency power ripples that are imposed on the DC bus. The proposed method compensates power ripple due to non-linear loads, linear loads, distorted grids, and load variations. Moreover, the compensation method does not require additional components that are commonly used with the existing power ripple compensators. Furthermore, practical considerations of the proposed control are discussed in the paper regarding stabilization of the nanogrid in case of lack of critical damping. The analysis and results demonstrated that a 50 µF total capacitance is sufficient at the DC bus for 500V/5kW DC nanogrid to achieve negligible DC bus voltage ripple. Thereby, with such small DC nanogrid input capacitance, the DC link capacitor can be a film type capacitor to enhance the reliability of the nanogrid.

中文翻译：

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通过固态转换器的直流纳米电网功率纹波补偿器

本文提出了一种通过降低输入电容要求来提高DC纳米电网可靠性的方法。通过利用固态转换器（SSC）的零序工作模式，降低了纳米电网DC总线的电容要求。该SSC通常被视为主要的DC纳米电网能源控制单元，它将纳米电网与主要的公用交流电网连接起来并管理纳米电网要素。所提出的方法在SSC AC滤波电容器中注入零序电压，以补偿施加在DC总线上的低频电源纹波。所提出的方法补偿了由于非线性负载，线性负载，扭曲的电网和负载变化引起的功率纹波。此外，补偿方法不需要现有电源纹波补偿器通常使用的其他组件。此外，在缺乏关键阻尼的情况下，在论文中讨论了有关纳米网格稳定性的建议控制的实际考虑。分析和结果表明，对于500V / 5kW DC纳米电网，DC总线上的总电容为50 µF就足以实​​现可忽略的DC总线电压纹波。因此，利用如此小的DC纳米网格输入电容，DC链路电容器可以是膜型电容器，以增强纳米网格的可靠性。