Under abnormal operating conditions such as limited power operation and faults of grid-forming units,the traditional distributed coordination control method of islanded AC/DC hybrid microgrid clusters is prone to losing support for AC bus voltage and frequency,resulting in system instability.To tackle this issue,a distributed coordina-tion control strategy for islanded AC/DC hybrid microgrid clusters under such conditions is proposed here-in.When the grid-forming units of an AC microgrid operate under limited power or faulty condition,in the abnormal grid-forming units microgrid converters control layer,the output power of grid-forming units is limited or they exit opera-tion.The secondary coordination control is then applied to control the grid-following units and their interlinking con-verter to ensure reasonable power allocation.In the interlinking converters control layer,the interlinking converter connected to the abnormal grid-forming units microgrid switches to a grid-forming control mode,providing neces-sary bus voltage and frequency support to this microgrid.The other interlinking converters share power supply with abnormal microgrid according to the remaining capacity of normal microgrids.Simulation results under various sce-narios indicate that when there is an increased load and grid-forming units operate under limited power condition,the proposed distributed coordination control strategy enables fast recovery of AC bus voltage and frequency in the ab-normal microgrid and ensures precise power allocation among grid-following units through the variable mode opera-tion of interlinking converters.Furthermore,when grid-forming units fail,the proposed strategy can effectively solve the instability problem of abnormal microgrid caused by the loss of support from AC bus voltage and frequency.
关键词
孤岛交直流混合微电网群/分布式协同控制/构网型单元/异常运行工况/电压与频率支撑/功率分配
Key words
islanded AC/DC hybrid microgrid cluster/distributed coordination control/grid-forming unit/abnormal operating condition/voltage and frequency support/power allocation
维普
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