Backup apparatus and power converter

A power converter comprising:

• an inverter circuit configured to convert a direct current from a photovoltaic module into an alternating current;
• a backup apparatus comprising a contactor, a first rectifier circuit, a first switch, a second switch, and an auxiliary power supply circuit;
• and
• a controller, wherein the inverter circuit is configured to convert a direct current from a photovoltaic module or an energy storage battery into an alternating current, the backup apparatus comprises a contactor, a first rectifier circuit, a first switch, a second switch, and an auxiliary power supply circuit, the contactor comprises a coil and a main contact switch, the main contact switch is connected between a power grid and the inverter circuit, an input of the first rectifier circuit is connected to the power grid through the first switch, an output of the first rectifier circuit is connected to the coil, and the coil is further connected to the auxiliary power supply circuit through the second switch;
• the first rectifier circuit is configured to:
• when the first switch is turned on,
• convert an alternating current from the power grid into a direct current to supply power to the coil, to turn on the main contact switch;
• the controller is configured to:
• after the main contact switch is turned on,
• control the second switch to be turned on and the first switch to be turned off, so that the auxiliary power supply circuit converts an alternating current from the power grid into a direct current to supply power to the coil, to keep the main contact switch on;
• and
• the auxiliary power supply circuit comprises an input capacitor, and when the second switch is turned on, the input capacitor supplies power to the coil when a voltage of the power grid is lower than a voltage threshold.