针对光伏逆变器直流侧电容电压波动的问题,根据光伏逆变器直流电压波动的机理和其主要输出有功功率的特点,提出一种镜像虚拟电阻技术用以解决光伏逆变器直流电压波动的问题。该策略只需在逆变器正常工作的基础上增加少量计算,具有较高实用性。对于谐波分量,光伏逆变器等效为一个与基波等效电阻大小相等、方向相反的镜像虚拟电阻吸收电网谐波功率,同时可显著减小直流侧电压波动的问题。仿真和实物实验结果均验证了该策略的有效性。
Abstract
When the grid contains harmonic components, the DC side capacitor of the photovoltaic inverter will produce voltage ripple, which will not only affect the service life of the DC container, but also reduce the power quality of the system. According to the mechanism of DC voltage fluctuation of PV inverter and its characteristic of only outputting active power, this paper proposes a mirror virtual resistance technology to solve the problem of DC voltage fluctuation of PV inverter. This strategy only needs to add a small amount of calculation on the basis of the normal operation of the inverter, which can suppress the fluctuation of DC voltage and improve the power quality of PCC point, and has high practicability. For the harmonic component, the photovoltaic inverter is equivalent to a mirror virtual resistance with the same size and opposite direction as the fundamental equivalent resistance to absorb the harmonic power, and significantly reduce the DC side voltage fluctuation. The simulation and physical experiment results verify the effectiveness of the strategy.
关键词
直流电压波动 /
瞬时无功功率 /
虚拟电阻 /
镜像虚拟电阻 /
谐波抑制 /
光伏逆变器
Key words
DC voltage fluctuation /
instantaneous reactive power /
virtual resistance /
mirror virtual resistance /
harmonic suppression /
photovoltaic inverter
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基金
广东省基础与应用基础研究基金（2021A1515012616）
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