Power Decoupling Strategy for Virtual Synchronous Generator Relaxing Condition of Small Power Angle

The virtual synchronous generator (VSG) may produce output power error, amplify power oscillation and even become invalid due to the power coupling. To tackle this issue, a novel power decoupling method which relaxes the small power angle condition is proposed based on the power decoupling mechanism. The proposed method can decouple the active and reactive power more accurately. Furthermore, the state space small signal model of improved VSG control strategy based on the proposed decoupling method is built, and the stability and power coupling characteristics are analyzed. By contrastive analysis, it is proved that the proposed method can weaken the coupling influence between the active power and reactive power loop more effectively. In addition, the proposed decoupling method increases the gain margin and phase margin, and thus enhances the system stability. Finally, the experimental results validate that the proposed method can eliminate the power steady-state error and dynamic oscillation and improve the dynamic and steady-state response performance of active and reactive power.