Parameters Sensitivity Analysis of Circulating Resonance in Islanded Micro-grid with Aggregated Droop-Based Control Inverters

Circulating resonance is studied among aggregated droop controlled inverters in islanded micro-gird. Firstly, the output impedance of droop control inverter is obtained by small signal method. And parameter sensitivity of the impedance is analyzed, which reveals that the lower-frequency impedance is sensitive to Q-U control parameters in droop control, and higher-frequency impedance is impacted by voltage loop control parameters and
$\boldsymbol{C}$
value of LC filters. Then circulating resonance is analyzed based-on the derived output impedance. Through disturbing voltage loop control parameters and
$\boldsymbol{C}$
value, it discloses that, resonant frequency is sensitive to
$\boldsymbol{C}$
value, and the oscillation will be suppressed with increase of
$\boldsymbol{C}$
value. However, the frequency is less sensitive to voltage loop parameters, and the resonance will be amplified by increasing voltage loop control parameters, especially voltage proportional control parameters. Finally, the circulating resonance is verified by simulations and experiments.