A Novel Order Reduced Synchronous Power Control for Grid-Forming Inverters

Abstract

Nowadays, the grid-forming inverter, also referred as the voltage-controlled inverter, has gained greater attention due to its advantages in providing power support to the grid. The power control is central to grid-forming inverters in realizing grid-support functionalities, such as the droop control or virtual inertia emulation. However, in these controls, the dynamic response of the instantaneous power usually suffers from overshoots and oscillations. To improve the dynamic response of the injected instantaneous power, this letter introduces a novel synchronous active power control for the voltage-controlled grid-connected inverter. The droop coefficient can be released from adjusting the damping factor of the system. A novel design method is proposed to reduce the second-order power loop to a first-order model. Consequently, the droop and reference-following controls operate like a first-order system with an excellent dynamic response. Moreover, the virtual inertia can be designed freely without affecting the performance of the power control. The correctness of the control is verified experimentally.