VSG Transient Power Angle Stabilization Strategy Considering Current Limiting

Abstract

Virtual synchronous generators (VSGs) can imitate the output characteristics of traditional synchronous generators, which means that when the frequency or voltage of the system fluctuates, the VSG can use the inertia and damping characteristics to smooth the fluctuations as much as possible. VSG also has transient stability problems under large disturbances, but its overcurrent capability is far less than that of traditional synchronous generators. Therefore, it is necessary to limit the overcurrent while maintaining the transient power angle stability of the system. Most of the existing studies analyze the overcurrent limit and transient power angle stability respectively, but the control strategies considered both are also worthy of attention and research. This paper firstly analyzes the current limiting control of VSG and its influence on the virtual power angle characteristic through the vector diagram. Then, the transient power angle stability of the system is studied under the condition of current saturation through the power angle characteristic curve. On this basis, a transient power angle stabilization method is proposed to keep the virtual power angle unchanged at the initial steady state value while limiting overcurrent. Finally, the rationality of the proposed strategy is verified by simulations on MATLAB/Simulink.