摘要
电网含有较丰富的电网电压背景谐波和较大的电网等效阻抗,会对光伏并网逆变器的入网电流质量和系统稳定性产生影响。以LCL型滤波单相光伏并网逆变器的双环无源阻尼控制方案为例,指出常规电网电压比例前馈控制在弱电网条件下不能完全消除电网电压谐波的影响,且系统稳定性会受到电网阻抗变化的影响。文章提出了一种通过并网电压完全补偿的全前馈控制策略,该方法能够使得电压谐波对入网电流的影响降至最低,并且控制稳定性也不受电网阻抗的影响,对弱电网有很强的适应性,仿真实验验证了该控制策略的有效性。
Weak network contains rich background harmonies in grid voltage and large power grid equivalent impedance, which will influence the grid current quality and the stability of photovoltaic grid connected inverter. The paper started from double passive damping control scheme of single-phase LCL filter photovol- talc grid connected inverter as an example. It is pointed out that the conventional voltage proportional feedforward control in a weak network will not completely eliminate the influence of voltage harmonic of power network and the system stability will be influenced by grid impedance variation. This article put forward the grid voltage feed-forward control strategy which can completely eliminate the influence of voltage harmonics on grid current. In addition, the system stability will not affected by the grid impedance and the system has strong adaptability to the weak power grid. The effectiveness of the proposed method was verified by simulation.
出处
《微电机》
2017年第8期38-42,47,共6页
Micromotors
基金
国家自然科学基金项目(51277051)
关键词
弱电网
LCL型滤波
光伏并网逆变器
前馈控制
稳定性
weak gird
LCL filter
photovohaic grid-connected inverter
feedforward control
system stability
