Power supply apparatus, three-phase transformer circuit, and charging pile

A power supply apparatus, comprising:

• a turns ratio switching circuit, a connection relationship switching circuit, a three-phase transformer, and two three-phase rectifier bridge circuits;
• a three-phase primary winding of the three-phase transformer is configured to receive a three-phase alternating current, a three-phase secondary winding of the three-phase transformer is configured to output a three-phase alternating current to each of the two three-phase rectifier bridge circuits, and a running mode of the three-phase transformer comprises a first turns ratio mode and a second turns ratio mode;
• the turns ratio switching circuit is configured to switch a quantity of turns of the three-phase primary winding, to switch the running mode of the three-phase transformer, a quantity of turns of a primary winding of each phase comprises a first quantity of turns and a second quantity of turns, the second quantity of turns is greater than the first quantity of turns, the first quantity of turns corresponds to the first turns ratio mode, and the second quantity of turns corresponds to the second turns ratio mode;
• and
• the connection relationship switching circuit is configured to switch a connection relationship between the two three-phase rectifier bridge circuits, and the two three-phase rectifier bridge circuits are connected in series or in parallel through the connection relationship switching circuit,
• wherein the turns ratio switching circuit or the connection relationship switching circuit is configured to adjust an output voltage range of the power supply apparatus;
• in response to the turns ratio switching circuit being configured to switch the running mode of the three-phase transformer and the connection relationship switching circuit being configured to switch the connection relationship between the two three-phase rectifier bridge circuits, an output voltage of the power supply apparatus falls within at least one of a first voltage range, a second voltage range, a third voltage range, or a fourth voltage range;
• and
• an upper limit of the first voltage range is less than or equal to a lower limit of the second voltage range, and an upper limit of the third voltage range is less than or equal to a lower limit of the fourth voltage range, and
• wherein the power supply apparatus comprises a three-phase inverter bridge circuit, three bridge arm midpoints of the three-phase inverter bridge circuit output a three-phase alternating current to three primary windings of the three-phase transformer through a three-phase resonant circuit, and the three-phase inverter bridge circuit is configured to:
• run in a first switching frequency range in response to that a parallel voltage of the two three-phase rectifier bridge circuits falls within the second voltage range, that a series voltage of the two three-phase rectifier bridge circuits falls within the third voltage range or the fourth voltage range, that the connection relationship switching circuit connects the two three-phase rectifier bridge circuits in series, or that the connection relationship switching circuit connects the two three-phase rectifier bridge circuits in parallel and the three-phase transformer runs in the first turns ratio mode, wherein an upper limit of the first switching frequency range is less than or equal to resonant frequencies of the three-phase transformer and the three-phase resonant circuit;
• and
• run, based on a result of comparing the parallel voltage of the two three-phase rectifier bridge circuits with a voltage threshold, at the first switching frequency range or in a second switching frequency range in response to that the parallel voltage of the two three-phase rectifier bridge circuits falls within the first voltage range, or that the connection relationship switching circuit connects the two three-phase rectifier bridge circuits in parallel and the three-phase transformer runs in the second turns ratio mode, wherein a lower limit of the second switching frequency range is greater than the resonant frequency of the three-phase resonant circuit, and the another voltage threshold is greater than a lower limit of the first voltage range and less than the upper limit of the first voltage range.