考虑故障限流的VSG暂态功角稳定控制方法

当电网发生严重故障时，虚拟同步发电机(VSG)易发生功角失稳并导致故障电流越限，现有方法大多忽略功角失稳与故障过流之间的内在关联性而将二者单独处理，导致二者难以同时解决。为此，分析了VSG的暂态功角特性和故障电流特性，阐释了产生上述问题的原因及相互关系；基于相图理论分析了多影响因素下VSG的暂态功角稳定性，提出了一种考虑故障限流的VSG暂态功角稳定控制方法，该方法在自适应调节有功功率指令以保持功角稳定的基础上联合调节无功调压系数，并引入准静态近似虚拟阻抗，同时实现了故障期间VSG的暂态功角稳定和全故障限流。仿真和实验结果验证了理论分析的正确性及所提控制方法的有效性。

Transient power angle stability control method of VSG considering fault current limitation

When a serious fault occurs in the power grid, the virtual synchronous generator(VSG) is prone to power angle instability and fault current exceeding the limit. Most of the existing methods ignore the internal correlation between power angle instability and fault overcurrent and deal with them separately, which makes it difficult to solve the two problems simultaneously. Therefore, the transient power angle characteristic and fault current characteristic of VSG are analyzed, and the causes and relations of the above problems are explained. Based on the phase diagram theory, the transient power angle stability of VSG under multiple influencing factors is analyzed, and a transient power angle stability control method of VSG considering fault current limitation is proposed. On the basis of adaptively adjusting the active power command to keep the power angle stable, the proposed method regulates the reactive power regulation coefficient jointly. In addition, a quasi-static approximate virtual impedance is introduced to realize both transient power angle stability and total fault current limitation of VSG during fault. Simulative and experimental results verify the correctness of the theoretical analysis and the effectiveness of the proposed control method.