Zero-sequence Circulating Current Suppression Strategy for Microgrid Inverters

The parallel connection of inverters in the microgrid system increases the system capacity, but also provides a basis for the generation of zero sequence circulating current (ZSCC). In order to solve the problems of system loss caused by ZSCC, an improved controller was designed. Based on the traditional linear active disturbance rejection control (LADRC), the controller adds compensation for the total disturbance estimation error, which improves the performance of the controller. In this way, zero-vector allocation factor is obtained to adjust the duty cycle, eliminate the difference between the inverters, and thereby suppress ZSCC. Finally, the simulation results verify the reference effect of the control strategy on suppressing ZSCC.