A combined regulation method of transient power angle stability control and fault current suppression for VSG.

• By the characteristic analysis of VSG, the causes and influencing factors of TPAI and FOC are revealed, and the inherent relationship between TPAI and FOC is found. • Based on the phase portrait theory, the stability analysis of different influencing factors is carried out. It is found that the proposed method can significantly enhance the TPAS of VSG under serious grid faults. • According to the verification results, the proposed method can simultaneously realize the TPAS and FCS of VSG during the fault, and the virtual inductance based on QSA can effectively suppress IIC. In addition, this method has the advantages of simple operation, no need to freeze the reactive power loop, and strong adaptability to engineering application problems such as considering the change of fault impedance and the difficulty of grid fault voltage measurement. When a serious grid fault occurs, a virtual synchronous generator (VSG) tends to lose transient power angle stability (TPAS) and cause the fault current to exceed the limit. Most existing research usually neglects the inherent relationship between transient power angle instability (TPAI) and fault over-current (FOC), which leads to the two problems being solved separately rather than simultaneously. In this paper, the transient power angle and fault current characteristics of VSG are first studied, and the causes and influencing factors of TPAI and FOC are explored. Then, the TPAS analysis is carried out based on the phase portrait theory. A TPAS control method for VSG considering fault current suppression (FCS) is proposed. This method is fulfilled by the combined regulation of active power reference and reactive voltage regulation coefficient, in which the reference and coefficient can be adjusted adaptively according to different fault degrees and application scenarios. In addition, a quasi-static approximate (QSA)virtual inductance is introduced to limit the instantaneous inrush current (IIC). The proposed method achieves both the TPAS and FCS at the same time during the fault. Finally, simulations and experiments verify the correctness of the theoretical analysis and the proposed method. [ABSTRACT FROM AUTHOR]