Multi-machine grid-connected control system and control method thereof

The invention discloses a multi-machine grid-connected control system and a control method thereof, belongs to the technical field of multi-machine grid-connected control, and aims to solve the problem that existing multi-machine grid-connected control cannot give consideration to multiple oscillation sources. The multi-machine grid-connected control system comprises a pulse width modulation module which is used for controlling the output voltage of an inverter; the unit module comprises a leading unit and a plurality of following units, the input end of the unit module is simultaneously connected with the output end of the pulse width modulation module, and the output end of the unit module is simultaneously connected with a power transmission line and a power grid part; and the control module comprises a first control structure and a plurality of second control structures. According to the invention, power oscillation between units and power oscillation between the units and a power grid can be considered.