For islanded microgrids using virtual synchronous generator-based secondary voltage control

existing approaches depend heavily on continuous communication and exhibit a significant gap between the theoretical convergence upper bound and the actual convergence time. To address these issues

this paper proposes a preset-time consensus algorithm enhanced with an event-triggered mechanism. First

an event-triggered strategy is designed based on state error thresholds

enabling each inverter to communicate intermittently and only with its neighbors. This achieves voltage restoration without deviation and reactive power sharing according to inverter rating within a user-specified time. Then

the convergence of the proposed method is theoretically analyzed

and the possibility of Zeno behavior is excluded. Finally

a simulation platform of an islanded microgrid is built and the test results show that the system converges within the preset time. Compared with continuous communication schemes

the proposed method reduces communication events by more than 99% with almost no loss in recovery performance

significantly improving the efficiency and flexibility of microgrid control.