Photovoltaic Power Supply System and Control Method Thereof, and Air Conditioning Unit

Disclosed are a photovoltaic power supply system and a control method thereof, and an air conditioning unit. The system includes: a photovoltaic cell panel; a direct-current bus; a DC/DC converter, one end of which is connected to the photovoltaic cell panel, and the other end of which is connected to the direct-current bus; and a switch assembly arranged in parallel with the DC/DC converter, wherein one end of the switch assembly is connected to the photovoltaic cell panel, and the other end thereof is connected to the direct-current bus, and the switch assembly is used for controlling a grid connection mode of the photovoltaic cell panel. When the switch assembly is turned off, the photovoltaic cell panel is connected to the direct-current bus by means of the DC/DC converter; and when the switch assembly is turned on, the photovoltaic cell panel is directly connected to the direct-current bus.