The hybrid AC/DC admittance of interlinking converters operating under AC voltage control mode may contain right half-plane (RHP) pole(s), and thus, the existing harmonic stability analyses on grid-tied interlinking converter systems may become inapplicable as well. Aiming at addressing this deficiency, this letter modifies the hybrid AC/DC admittance definition and re-studies the harmonic stability of a grid-tied interlinking converter operating under AC voltage control mode. The results reveal that when the control mode of an interlinking converter changes from P/QP/Q control to AC voltage control, the system minor-loop gain utilized to assess the AC-side stability evolves to its inverse matrix. In contrast, the stability assessment related to the DC side (and the coupling interaction between the AC and DC sides) remains unchanged. Furthermore, the DC- and AC-side stabilities can also be regulated independently and are dominated by the dd-axis and the qq-axis controllers, respectively.

中文翻译：

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交流电压控制模式下并网互联变流器系统谐波稳定性分析


在交流电压控制模式下运行的互连变流器的混合交直流导纳可能包含右半平面（RHP）极点，因此现有的并网互连变流器系统的谐波稳定性分析也可能变得不适用。针对这一不足，本文修改了混合交直流导纳的定义，并重新研究了交流电压控制模式下并网互联变流器的谐波稳定性。结果表明，当互连变流器的控制模式从P/QP/Q控制变为交流电压控制时，用于评估交流侧稳定性的系统小环增益演化为其逆矩阵。相比之下，与直流侧（以及交直流侧之间的耦合相互作用）相关的稳定性评估保持不变。此外，直流侧和交流侧的稳定性也可以独立调节，并分别由dd轴和qq轴控制器控制。