Power supply system and switch unit

A power supply system, comprising a control unit, a switch, a direct current source, and a power conversion unit, wherein the switch is electrically connected between the direct current source and the power conversion unit, the control unit is configured to send a switch-off signal to the switch when the direct current source or the power conversion unit is faulty, the switch comprises a switch unit and an operating mechanism, the operating mechanism is configured to receive the switch-off signal and control the switch unit to be opened or closed, and the switch unit comprises:

• an arc-extinguishing functional component;
• a fixed contact assembly, located inside the arc-extinguishing functional component;
• a moving contact, located inside the arc-extinguishing functional component and configured to move relative to the fixed contact assembly, wherein the operating mechanism controls the switch unit to be opened when receiving the switch-off signal, so that the moving contact is separated from the fixed contact assembly, and an electric arc is formed between the moving contact and the fixed contact assembly in a separation process;
• and
• a first magnet assembly, wherein directions of at least some magnetic induction lines of the first magnet assembly intersect a current direction of the electric arc to drive the electric arc to move towards the arc-extinguishing functional component, the first magnet assembly comprises a first magnet and a second magnet that are spaced apart, and the first magnet and the second magnet are both configured to increase a movement path of the electric arc or increase a contact area between the electric arc and the arc-extinguishing functional component to improve cooling effect of the arc-extinguishing functional component on the electric arc.