The LCL-type grid-connected inverter (GCI) is widely adopted between distributed generation (DG) and power grid to realize DC/AC power conversion. However, the underdamped LCL filter will cause a resonance phenomenon near the control stability boundary, which may lead to instability of the GCI system. The traditional passive damping method will cause power loss, while the active damping method may have the need for additional sensors or be sensitive to parameter changes. In this article, a control scheme based on active disturbance rejection control (ADRC) is proposed for the LCL-type GCI, and the systematic parameter design method is presented through root locus analysis. With the proposed strategy, only the grid-injected current is sensed to achieve the objectives of grid-injected current direct control and robust resonance damping for the LCL-type GCI. In the design process, the influence of digital control delay and grid impedance uncertainty on system stability is explicitly analyzed in detail. Through this, the GCI can work stably over a wide range of the typical inductive-resistive grid impedance. In addition, it is found that the proposed strategy also has good adaptability to the filter parameter perturbation. Simulation and experimental results validate the theoretical analysis in this paper.

中文翻译：

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LCL型并网逆变器基于有源干扰抑制控制的单电流反馈谐振阻尼策略

LCL型并网逆变器（GCI）被广泛用于分布式发电（DG）和电网之间，以实现DC / AC电力转换。但是，欠阻尼的LCL滤波器将在控制稳定性边界附近引起谐振现象，这可能导致GCI系统不稳定。传统的被动阻尼方法会导致功率损耗，而主动阻尼方法可能需要额外的传感器或对参数变化敏感。本文针对LCL型GCI提出了一种基于主动抗扰控制（ADRC）的控制方案，并通过根源分析提出了系统的参数设计方法。根据拟议的策略，仅感测电网注入电流，以实现针对LCL型GCI的电网注入电流直接控制和鲁棒谐振阻尼的目标。在设计过程中，详细分析了数字控制延迟和电网阻抗不确定性对系统稳定性的影响。通过这种方式，GCI可以在典型的感应电阻电网阻抗的宽范围内稳定工作。另外，发现所提出的策略还对滤波器参数摄动具有良好的适应性。仿真和实验结果验证了本文的理论分析。GCI可以在典型的感应电阻电网阻抗的宽范围内稳定工作。另外，发现所提出的策略还对滤波器参数摄动具有良好的适应性。仿真和实验结果验证了本文的理论分析。GCI可以在典型的感应电阻电网阻抗的宽范围内稳定工作。另外，发现所提出的策略还对滤波器参数摄动具有良好的适应性。仿真和实验结果验证了本文的理论分析。