The coordinated control of parallel three-phase four-wire converters in autonomous AC microgrids is investigated in this paper. First

based on droop control

virtual impedance is inserted in positive-

negative-and zero-sequences to enhance system damping and imbalance power sharing. Then

to facilitate virtual impedance design

small signal models of the three-sequence equivalent circuits are established respectively. Corresponding indexes are proposed to comprehensively evaluate the impact of sequence virtual impedance on current sharing accuracy

voltage quality at the point of common coupling (PCC) and system stability. In addition

constraint of DC-link voltage is also considered to avoid over modulation when subjected to unbalanced loads. Furthermore

to address the PCC voltage degradation resulting from virtual impedance

a voltage imbalance compensation method

based on low-bandwidth communication

is proposed. Finally

simulation and experimental results are provided to verify the correctness of the theory model

indicating that the proposed method can achieve PCC voltage restoration while guaranteeing the current sharing accuracy with desirable dynamics.