Resonance is one of the most significant challenges in a voltage source inverter interfaced with the grid through an LCL filter. The capacitor current (CC) damping control methodology is considered due to its high-quality of grid injected current feature. It is widely accepted that the proportional CC feedback compensation damping method becomes ineffective at critical resonance frequency due to control loop delays and may result in an unstable system under grid impedance or filter parameters variations. A suitable differential compensator placed in the CC feedback path can address this issue with a trade-off between robustness and noise rejection capability. This paper offers a different design method called parallel feedforward compensation (PFC) method, which builds an almost strictly real positive (ASRP) plant and realized damping with enhanced stability features. In the proposed alternative, a compensator consisting of a damping gain and a sampled delay is placed across the filter plant and filter CC feedback loop and the joint output of this augmented plant is then transmitted back at the reference point on the input side of the inverter to attenuate the undesirable resonance peak. The control response and stability performance analysis show that the suggested methodology offers a wide damping region, high robustness, and improved control performance. Simulation and experimental results are presented to confirm the theoretical findings.

中文翻译：

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基于严格实数正工厂策略的并网逆变器LCL滤波器谐振抑制

在通过 LCL 滤波器与电网连接的电压源逆变器中，谐振是最重大的挑战之一。电容器电流 (CC) 阻尼控制方法因其高质量的电网注入电流特性而被考虑。人们普遍认为，由于控制回路延迟，比例 CC 反馈补偿阻尼方法在临界谐振频率下变得无效，并且可能导致在电网阻抗或滤波器参数变化的情况下系统不稳定。在 CC 反馈路径中放置一个合适的差分补偿器可以通过在鲁棒性和噪声抑制能力之间进行权衡来解决这个问题。本文提供了一种不同的设计方法，称为并行前馈补偿 (PFC) 方法，它建立了一个几乎严格的实正（ASRP）工厂并实现了具有增强稳定性特征的阻尼。在提议的替代方案中，由阻尼增益和采样延迟组成的补偿器被放置在滤波器设备和滤波器 CC 反馈环路中，然后该增强设备的联合输出在逆变器输入侧的参考点传输回衰减不需要的共振峰。控制响应和稳定性能分析表明，所建议的方法提供了宽阻尼区域、高鲁棒性和改进的控制性能。给出了仿真和实验结果以证实理论发现。一个由阻尼增益和采样延迟组成的补偿器被放置在滤波器设备和滤波器 CC 反馈回路中，然后该增强设备的联合输出被传输回逆变器输入侧的参考点，以衰减不需要的谐振顶峰。控制响应和稳定性能分析表明，所建议的方法提供了宽阻尼区域、高鲁棒性和改进的控制性能。给出了仿真和实验结果以证实理论发现。一个由阻尼增益和采样延迟组成的补偿器被放置在滤波器设备和滤波器 CC 反馈回路中，然后该增强设备的联合输出被传输回逆变器输入侧的参考点，以衰减不需要的谐振顶峰。控制响应和稳定性能分析表明，所建议的方法提供了宽阻尼区域、高鲁棒性和改进的控制性能。给出了仿真和实验结果以证实理论发现。控制响应和稳定性能分析表明，所建议的方法提供了宽阻尼区域、高鲁棒性和改进的控制性能。给出了仿真和实验结果以证实理论发现。控制响应和稳定性能分析表明，所建议的方法提供了宽阻尼区域、高鲁棒性和改进的控制性能。给出了仿真和实验结果以证实理论发现。