DC-link voltage control strategy for reducing capacitance and total harmonic distortion in single-phase grid-connected photovoltaic inverters
DC-link voltage control strategy for reducing capacitance and total harmonic distortion in single-phase grid-connected photovoltaic inverters
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DOI：
10.1049/iet-pel.2014.0453
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发表时间：
2015-04
影响因子：
2
通讯作者：
Yihua Hu;Yang Du;W. Xiao;S. Finney;W. Cao
中科院分区：
文献类型：
--
作者：
Yihua Hu;Yang Du;W. Xiao;S. Finney;W. Cao
在单相光伏并网逆变器中，需要大容量的电容来缓冲输入和输出端口之间的功率差，这成为了提高系统效率和延长器件寿命的障碍。此外，当系统运行到低功率电平时，总的谐波失真变得严重。本文对两级拓扑结构进行了综合分析，综合考虑了有功功率、直流侧电压、纹波和电容等因素。本研究提出了一种综合的DCL电压控制策略，在保持系统正常运行的同时最小化DCL电容。此外，所提出的控制策略可以灵活地与跳脉冲控制相结合，显著改善了光功率条件下的电能质量。由于所提出的控制策略需要改变DCL的电压，因此还引入了有源保护方案来防止DCL上的任何电压违规。通过仿真和实验对所提出的控制策略进行了评估，结果证实了系统的有效性。
High-volume capacitance is required to buffer the power difference between the input and output ports in single-phase grid-connected photovoltaic inverters, which become an obstacle to high system efficiency and long device lifetime. Furthermore, total harmonic distortion becomes serious when the system runs into low power level. In this study, a comprehensive analysis is introduced for two-stage topology with the consideration of active power, DC-link (DCL) voltage, ripple and capacitance. This study proposed a comprehensive DCL voltage control strategy to minimise the DCL capacitance while maintaining a normal system operation. Furthermore, the proposed control strategy is flexible to be integrated with the pulse-skipping control that significantly improves the power quality at light power conditions. Since the proposed control strategy needs to vary DCL voltage, an active protection scheme is also introduced to prevent any voltage violation across the DCL. The proposed control strategy is evaluated by both simulation and experiments, whose results confirm the system effectiveness.