In this article, the stability robustness of repetitive control (RC) in the grid-tied inverter is discussed. Due to the limited control band, high-frequency characteristics of the control plant are seriously affected by the modeling and parameter uncertainties, which can lead to RC controller instability. Then, an infinite impulse response (IIR) low-pass filter is applied inside the internal model of RC to improve the stability robustness. To alleviate the effects of the RC gain reduction induced by the phase lag of the IIR filter, an approximated simple computational method of the phase compensation is proposed. The situation of the gain attenuation and frequency deviation of RC caused by the IIR filter is analyzed, and a method that modifies the phase compensator in real time for the IIR filter is applied to resist the grid frequency variation. Parameter design is provided in details, and comparison experiments are performed in different uncertainty situations to demonstrate the effectiveness of the proposed approach.

中文翻译：

---

使用IIR滤波器的并网逆变器重复控制的参数鲁棒性改进

在本文中，讨论了并网逆变器中重复控制（RC）的稳定性鲁棒性。由于控制频带有限，建模和参数不确定性严重影响了控制设备的高频特性，这可能导致RC控制器不稳定。然后，在RC的内部模型内部应用无限脉冲响应（IIR）低通滤波器，以提高稳定性。为了减轻IIR滤波器的相位滞后引起的RC增益降低的影响，提出了一种近似简单的相位补偿计算方法。分析了IIR滤波器引起的RC增益衰减和频率偏差的情况，并采用一种实时修改IIR滤波器相位补偿器的方法来抵抗电网频率变化。