Virtual impedance design method and system considering high-precision power output of inverter

The invention provides a virtual impedance design method and system considering high-precision power output of an inverter, and is suitable for a capacitive coupling inverter. The method comprises the following steps: firstly, selecting an equivalent coupling impedance boundary according to an active power output limit value calculated by physical impedance; secondly, adding an inner boundary and an outer boundary which meet the transient response requirement, and narrowing the selection range of virtual impedance; further, a stability margin parameter is introduced, the stability boundary of the coupling impedance is derived, and the selection range of the virtual impedance is further narrowed; secondly, considering possible power loss, and taking a range in which the equivalent impedance approaches zero as a feasible range of the equivalent coupling impedance; and finally, a virtual impedance value is obtained by using a difference value between the physical impedance and the equivalent coupling impedance.