一种基于自适应下垂与前馈控制的孤岛微电网构网型逆变器瞬态功率均分与解耦方法

Accurate power sharing is a basic demand for grid-forming inverters (GFMIs) in islanded microgrid (MG). However, even if the controllers of GFMIs are the same, the transient power sharing (TPS) performance will still be poor considering the differences from the circuit. In this article, a point-of-common-coupling (PCC) dynamic small-signal model is proposed to describe the interactions among GFMIs. Based on this model, an adaptive transient power decoupling (TPD) controller is derived first to assure good TPD performance and simplify the small-signal model of GFMIs. Then, an adaptive TPS controller is derived using adaptive droop and feedforward control to assure good TPS performance. Compared with traditional droop control method, the proposed method can compensate for voltage drop of line impedance and virtual impedance so that the steady state droop gains are maintained. Meanwhile, the differences of the circuit are canceled so that each GFMI has consistent dynamics, and the influence of operating point is canceled so that global optimal parameters design can be achieved. The effectiveness of the proposed method is verified by both simulations and experiments.