MULTI-INVERTER PARALLEL SYSTEM, AND GRID CONNECTION CONTROL METHOD FOR INVERTER

A multi-inverter parallel system and a method for controlling grid connection of an inverter are provided. The system includes a first inverter and a second inverter. The first inverter includes a first controller, a first inverter circuit, and a first relay. The second inverter includes a second controller, a second inverter circuit, and a second relay. Phases of an output end of the first inverter circuit are correspondingly connected to phases of an output end of the second inverter circuit. The first controller may control the first relay to be turned on. The second controller may control, when the second relay is turned off, a direct current bus voltage of the second inverter circuit to be the same as a direct current bus voltage of the first inverter circuit, and control a common-mode voltage injection manner of the second inverter circuit to be the same as a common-mode voltage injection manner of the first inverter circuit; and then control the second relay to be turned on, so that the second inverter operates in a grid-connected manner. In this way, a common-mode voltage output by the first inverter circuit is consistent with a common-mode voltage output by the second inverter circuit, which avoids affecting system reliability caused by a large common-mode circulating current impulse generated at a moment when the second relay is turned on.