Does grid impedance affect the stability of grid-connected inverters?

The stability analysis method based on impedance is used to analyse the influence of grid impedance on the stability of grid-connected inverters. Finally, the simulation finally proves the correctness of the analysis method.

What is a grid-connected inverter?

A grid-connected inverter equipped with an active online grid impedance estimation algorithm for stability analysis. Recently, there has been extensive research on the online wideband grid impedance using grid-connected inverters , , , , , , , , , , .

Can a grid connected inverter be measured with unknown grid impedance?

A new impedance measurement method for the grid-connected inverter with unknown grid impedance is proposed. The method conducts the measurement using FRA. Since the method is performed in the stationary frame, the synchronous angle concern occurred in the dq-frame measurement is avoided.

How do you analyze a grid connected inverter system?

For grid-connected inverter systems, stability analysis requires information about both the equivalent grid impedance seen by the inverter at its PCC and the inverter output impedance . Then, the ratio of these two impedances should satisfy the GNC in order for the system to be stable.

How does a grid interact with an inverter?

Interaction between the grid and the inverter may gener-ate harmonic resonances that lead to reduced power quality and even instability. To analyse the stability of the inverter-grid system using impedance-based stability criterion, inverter impedance has to be known.

Does grid impedance always exist?

In practical applications, when an inverter is connected to the grid, the grid impedance always exists and its effect to the inverter should be considered. Further, the grid impedance is usually unknown to the inverter and to the operator.