【摘要】 随着高比例可再生能源的接入，电网呈现弱电网特性。弱电网下，电网电压中存在的大量背景谐波会对并网逆变器的并网电流电能质量造成影响。通常采用电网电压前馈策略对背景谐波进行抑制，但由于电网阻抗的存在，采用传统前馈策略会降低并网逆变器的稳定裕度，引发谐波振荡问题甚至导致并网系统的不稳定。针对这一问题，本文提出一种基于加权比例微分的公共耦合点(PCC)电压前馈策略。首先，推导并建立了LCL型的并网逆变器等效阻抗模型，利用阻抗法分析弱电网下引入传统电压前馈策略对系统稳定性的影响，并通过绘制引入前馈前后并网逆变器等效输出阻抗比值的矢量图来揭示其幅相特性随频率的变化情况，在此基础上提出在前馈通道引入加权比例微分环节，并选取适宜的权重系数，实现对弱电网下并网逆变器谐波谐振的有效抑制。最后，基于Matlab/Simulink平台进行了仿真实验，验证了本文所提策略的可行性和有效性。更多还原

【Abstract】 With the high proportion of renewable energy being integrated into the grid, the grid presents weak grid characteristics. In conditions of a weak electrical grid, significant underlying harmonics in the grid’s voltage can adversely affect the power quality of the current supplied to the grid by an inverter that is connected to it. Commonly, the conventional method of grid voltage feedforward is employed to mitigate the effects of background harmonics. However, the presence of impedance in the grid can diminish the stability of the inverter that is tied to the grid. This may result in harmonic oscillations and potentially destabilize the entire grid-connected system. To tackle this issue, the article introduces a point of common coupling(PCC) grid voltage feedforward technique that utilizes a weighted proportional-derivative approach. Initially, the paper develops and establishes an equivalent impedance model for the grid-connected inverter. Furthermore, this study analyzes the impact of employing the conventional grid voltage feedforward method on system stability during weak grid scenarios, utilizing an impedance-based analysis. A vector diagram comparing the equivalent output impedance of the grid-tied inverter with and without the feedforward implementation is utilized to effectively mitigate the harmonic resonance issues of the inverter under weak grid conditions. Finally, simulations conducted within the Matlab/Simulink environment confirm the viability and efficacy of the proposed approach.更多还原