Transient Stability Enhancement for Virtual Synchronous Generator by Combining Direct Power Control

Virtual synchronous generator (VSG) control-based grid-connected converter (GCC) is an attractive method to solve the inertia issue of more renewable energy-integrated power system. However, The transient instability issues of VSG under grid faults may result in several security problems . To cope with the issue, this paper firstly analyzes the transient instability mechanism. It indicates that the roots of instability phenomenon are the continuous phase angle integration in active power loops caused by insufficient power transmission capacity, and the Q - v- i - P coupling. Based on it, a new direct power based VSG control (DPVSG) is proposed by combining the direct power control (DPC). With the method, the aforesaid power coupling can be significantly weakened, thus the transient stability can be improved. Finally, the proposed method is validated by the simulation.