Multi-split air conditioning system and control method thereof

The invention discloses a multi-split air conditioning system and a control method thereof, relates to the technical field of air conditioners, and aims to solve the problem that continuous operation of the multi-split air conditioning system is affected when an electrical box has a frosting risk. The multi-split air conditioning system comprises an outdoor unit, a controller and a plurality of indoor units. The outdoor unit comprises an electrical box, a refrigerant heat dissipation module is arranged on the electrical box, the refrigerant heat dissipation module comprises a refrigerant inlet and a refrigerant outlet, the outdoor heat exchanger comprises a first end and a second end, and the refrigerant inlet is connected with the first end; the indoor heat exchanger comprises a third end and a fourth end, the third end is connected with the second end, and the refrigerant outlet is connected with the fourth end; the controller is configured to obtain the temperature Tsc of a refrigerant at the refrigerant i