Soft start circuit of ups relay

A soft start circuit of a UPS relay, characterized by comprising a three-phase pre-charging module, a first PFC module, a second PFC module, a relay module, a three-phase input voltage detection module, a bus voltage detection module and a relay control module;

• wherein a first end of the relay module is connected to an A-phase mains input, a B-phase mains input and a C-phase mains input respectively, a second end of the relay module is connected to the first PFC module, and a third end of the relay module is connected to the second PFC module, and the first PFC module and the second PFC module are connected to a positive bus, a negative bus and an N line respectively;
• a first end of the three-phase pre-charging module is connected to the A-phase mains input, the B-phase mains input and the C-phase mains input respectively, and a second end of the three-phase pre-charging module is connected to the positive bus and the negative bus respectively;
• the three-phase input voltage detection module is connected to the A-phase mains input, the B-phase mains input and the C-phase mains input respectively to detect an A-phase input voltage, a B-phase input voltage and a C-phase input voltage;
• the bus voltage detection module is connected to the positive bus and the negative bus to detect a bus voltage;
• and
• the relay control module is electrically connected to the three-phase input voltage detection module and the bus voltage detection module and controls the connection of the relay module, to control part of relays in the relay module to be turned on based on the A-phase input voltage, the B-phase input voltage, the C-phase input voltage and the bus voltage to soft start the relay.