Robust Grid Current Control With Impedance-Phase Shaping for LCL-Filtered Inverters in Weak and Distorted Grid
Robust Grid Current Control With Impedance-Phase Shaping for LCL-Filtered Inverters in Weak and Distorted Grid
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DOI：
10.1109/tpel.2018.2808604
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发表时间：
2018-02
影响因子：
6.7
通讯作者：
Jinming Xu;Shaojun Xie;Binfeng Zhang;Qiang Qian
中科院分区：
文献类型：
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作者：
Jinming Xu;Shaojun Xie;Binfeng Zhang;Qiang Qian
对于并网型LCL滤波逆变器，电网电流反馈有源阻尼（AD）可以通过使用最少数量的传感器来保证期望的带宽和对某些参数变化的良好鲁棒性。然而，逆变器的性能受到公共耦合点（PCC）的非理想条件，包括背景电压畸变和电网阻抗变化的严重危害。电网电流AD不能很好地用于宽的电网阻抗变化。因此，在本研究中，此控制的鲁棒性进行了讨论，并通过数学推导得出其与系统参数的关系。证明了对于典型的电网电流AD控制，存在高带宽和高鲁棒性之间的矛盾。在分析典型控制局限性原因的基础上，提出了一种提高复杂电网条件下鲁棒性的系统方法。所提出的基本PCC电压前馈增强了鲁棒性，而所提出的相位成形补偿器确保了具有期望带宽的更高鲁棒性。通过与典型电网电流AD控制的对比波形，验证了分析的正确性和所提方法的改进。
For the grid-connected LCL-filtered inverter, the grid current feedback active damping (AD) can assure a desirable bandwidth and a good robustness against certain parameter variations by using a minimal number of sensors. However, the inverter performance was seriously endangered by nonideal conditions at the point of common coupling (PCC), including background voltage distortions and grid impedance variation. The grid current AD could not work well for wide grid impedance variation. Hence, in this study, the robustness with such control is discussed and its relations with system parameters are derived through mathematic derivations. It is proved that, for the typical grid current AD control, a contradiction between high bandwidth and high robustness exists. On the basis of analyzing the reasons for the limitations of the typical control, a systematic approach for enhancing the robustness under complex grid conditions has been proposed. The proposed fundamental PCC voltage feedforward enhances the robustness, while the proposed phase shaping compensator assures a higher robustness with a desired bandwidth. Comparative waveforms with the typical grid current AD control have been provided to verify the correctness of the analysis and the improvement of the proposed approach.