CPC B60L 58/12 (2019.02) [B60L 50/64 (2019.02); H02J 7/007 (2013.01); B60L 2210/10 (2013.01); B60L 2210/30 (2013.01)] | 20 Claims |
1. A charging and discharging device, comprising an alternating current/direct current (AC/DC) converter, a first direct current/direct current (DC/DC) converter, a second DC/DC converter and a control unit, wherein one end of the second DC/DC converter is connected between the first DC/DC converter and the AC/DC converter and the other end of the second DC/DC converter is connected to an energy storage unit; and
the control unit is configured to:
receive a first charging request transmitted by a battery management system (BMS) of a battery, the first charging request comprising a first charging voltage and a first charging current,
set output power of the first DC/DC converter as first output power of the first DC/DC converter based on the first charging voltage and the first charging current,
acquire a state of charge (SOC) of the energy storage unit,
turn on the second DC/DC converter under the condition that the SOC of the energy storage unit is greater than a first threshold, to charge the battery by the energy storage unit through the first DC/DC converter and the second DC/DC converter,
acquire a bus voltage of the charging and discharging device in real time, and
adjust output power of the second DC/DC converter to the first output power of the second DC/DC converter under the condition that the battery is charged by the energy storage unit, the bus voltage is less than a bus balance voltage and a difference between the bus voltage and the bus balance voltage exceeds a preset value, the first output power of the second DC/DC converter being less than or equal to a maximum output power of the second DC/DC converter,
wherein the difference between the bus voltage and the bus balance voltage is less than or equal to the preset value after the output power of the second DC/DC converter is adjusted to the first output power of the second DC/DC converter.
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