The smooth switching between grid-connected and islanded microgrid operation modes and the stability of system frequency are important guarantees for the safe and stable operation of a master-slave microgrid system.Combined with the operating characteristics of the microgrid system,an off-grid switching method based on phase angle switching is proposed,and a pre-synchronization control module is added to make sure that the grid phase is quickly tracked and compensated when the islanded mode is switched to the grid-connected mode,thereby solving the problem of shocks in the output voltage and current from master and slave inverters in switching.To ensure the frequency stability of the microgrid system,a V-F frequency control strategy based on fuzzy droop control is proposed and further applied to the smooth switching based on phase angle switching,so that the system frequency is basically maintained at 50 Hz and the problems of large oscillations in voltage and current and frequency shocks in switching are avoided.Finally,an experimental platform was built to verify the effectiveness and stability of the proposed method.
关键词
微电网主从结构/相位角平滑切换/预同步控制/模糊下垂的V-F控制
Key words
Master-slave structure of microgrid/smooth phase angle switching/pre-synchronization control/fuzzy drooping V-F control
维普
万方数据