Although virtual synchronous generator (VSG) alleviates low inertia and weak damping characteristics of new electricity system

it also introduces angle oscillation

leading to angle instability. Existing studies improve VSG control from the perspectives of control parameter adaptation and control loop reconstruction. There are still problems such as design difficulties and unclear physical meaning. To address the aforementioned issues

this paper firstly proposes an improved control idea by using virtual impedance for rapid attenuation of "angle energy" based on equal area criterion (EAC). The ideal explains physical meaning by graphical methods. Also

an algorithm is designed to calculate virtual impedance values of different stages. On this basis

possible problems in the improved control idea are analyzed. Secondly

to compensate for “damping work” and improve control applicability

a control strategy based on adaptive virtual impedance by frequency is constructed to achieve better suppression of power angle oscillation under different conditions. Finally

correctness of the above analysis is verified through electromagnetic transient simulation

and effectiveness of the proposed control strategy in improving angle stability is demonstrated.