Under weak grid conditions

coupling parallel inverters and grid impedance can easily cause harmonic resonance

seriously affecting the quality of grid-connected power.First

an equivalent circuit model for a multi-inverter parallel system is established

and the mechanism of harmonic resonance generation is analyzed from the perspective of impedance.Secondlly

by introducing a second-order low-pass filter into the PCC voltage feedforward channel of the inverter

the output impedance characteristics at the resonant frequency are enhanced

and its effectiveness is verified using impedance stability criteria.Finally

simulation experiments conducted in Simulink show that this method can effectively suppress the resonance hazards in multi-inverter parallel systems and improve the adaptability of inverters to weak grids.