Abstract: Although the parallel connection of inverters in a microgrid system increases the system capacity，it

creates a circulation path which provides the conditions for the generation of zero-sequence circulating current

（ZSCC）. In order to solve the problem of system loss caused by ZSCC，a ZSCC controller was designed. Based on

the traditional linear active disturbance rejection control（LADRC），in the proposed controller ，the linear state error feedback （LSEF） control law was improved，the compensation for the total disturbance estimation error was

increased，and the performance of the controller was enhanced. Thus，the accurate zero-vector allocation factor

could be obtained to adjust duty cycle，eliminate the difference between inverters，and then suppress ZSCC.

Finally，the immunity of the improved LADRC and the stability of the system were illustrated through theoretical

analysis. The simulation results verify the reference effect of the control strategy on the suppression of ZSCC.

      Key words: microgrid；inverter parallel connection；zero-sequence circulating current（ZSCC）；linear active

disturbance rejection control（LADRC）；zero-vector allocation factor