In the LCL-filtered grid-tied inverter, the classical low-cost control strategy which is composed of the single converter-side current control and the unit grid voltage feedforward compensation, is commonly employed to inject the sinusoidal current into the utility. However, the inverter output admittance features the non-passive behaviour, which indicates that the harmonic currents may be amplified under the disturbances of the grid voltage and the grid impedance. Therefore, two dedicated current loops based on only the converter-side current feedback are proposed, which consist of the low-pass filter-based current regulation and the high-pass filter-based active damping (HFAD). The mixed asymmetrical regular sampling method is further used to reduce the control delay of the HFAD. Moreover, the low-pass filter-based feedforward is developed to make a compromise between the disturbance rejection and the stability. Fair comparisons with other typical control strategies are made through analysing the virtual resistor in parallel with the filter capacitor, which reveals that the positive virtual resistance at the frequency lower than half of the switching frequency is maintained. With the elaborated control parameters, the exhaustive experimental results finally verify the effectiveness of the proposed method in passivating the inverter output admittance.

中文翻译：

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转换器侧电流控制并网逆变器的基于无源性的输出导纳整形，以提高对电网阻抗的鲁棒性

在经过LCL滤波的并网逆变器中，经典的低成本控制策略通常由单转换器侧电流控制和单位电网电压前馈补偿组成，以将正弦电流注入电网。但是，逆变器的输出导纳具有无源特性，这表明谐波电流可能会在电网电压和电网阻抗的干扰下被放大。因此，提出了仅基于转换器侧电流反馈的两个专用电流环路，它们由基于低通滤波器的电流调节和基于高通滤波器的有源阻尼（HFAD）组成。进一步采用混合不对称规则采样方法来减少HFAD的控制延迟。此外，开发了基于低通滤波器的前馈，以在干扰抑制和稳定性之间做出折衷。通过分析与滤波电容器并联的虚拟电阻器，与其他典型控制策略进行了合理的比较，这表明在低于开关频率一半的频率下，可以保持正虚拟电阻。借助详尽的控制参数，详尽的实验结果最终验证了所提出方法在钝化逆变器输出导纳方面的有效性。这表明在低于开关频率一半的频率处保持正虚拟电阻。借助详尽的控制参数，详尽的实验结果最终验证了所提出方法在钝化逆变器输出导纳方面的有效性。这表明在低于开关频率一半的频率处保持正虚拟电阻。借助详尽的控制参数，详尽的实验结果最终验证了所提出方法在钝化逆变器输出导纳方面的有效性。