POWER SUPPLY APPARATUS FOR CHARGING PILE

This application provides a power supply apparatus, a three-phase transformer circuit, and a charging pile. A connection relationship or a turns ratio of at least one of primary-side windings or secondary-side windings in a three-phase transformer may be switched by using a winding switching switch, to extend an output voltage range of the power supply apparatus or the charging pile, and improve conversion efficiency of the power supply apparatus or the charging pile. The power supply apparatus provided in this application includes a three-phase transformer and a winding switching switch module. The winding switching switch module includes at least one of a winding connection switching switch group or a winding turn number switching switch group. The winding switching switch module is configured to switch a turns ratio or a connection manner of the three-phase transformer. The winding connection switching switch group is configured to switch a connection manner of the three primary-side windings or a connection manner of the three secondary-side windings, and the winding turn number switching switch group is configured to switch turn numbers of the three primary-side windings or turn numbers of the three secondary-side windings, to extend the output voltage range of the power supply apparatus or the charging pile.