Exchanged Virtual Synchronous Generator Control Method for Grid-Tied Inverter with Strengthened Frequency Support

Traditional VSG is prone to oscillation when attached to strong grids especially when distribution line is more resistive. To tackle this issue, this letter proposes an exchanged virtual synchronous generator (eVSG) control strategy with exchanging the active- and reactive-power loop for strengthened frequency support capability. Specifically, the reactive-power is regulated to form the frequency and phase angle, but the active-power is controlled to form the voltage magnitude as required for PWM signals. It is found that the frequency stability margins with the eVSG control is better than that of the conventional VSG control strategy. Finally, the proposed eVSG strategy as well as analysis is validated by experiments.