Greater capacity of UPS is usually achieved by parallel operation of inverters.Minor difference between inverter voltage magnitude,frequency and phase will trigger great circulating current,which attaches great importance to current sharing.At present,lots of solution have been proposed.Droop control without communication connection and virtual impedance are promising method.In a paper,equal virtual resistance and inductance are introduced and by linear combination of power the coupling between active and reactive power is decreased,which leads to better performance.This paper analyzes the deficiency of this method and points out that voltage correction is essential.Correction method is also provided and Mtalab simulation is carried out to confirm the effectiveness.
