Electrical charging system

A motor vehicle in combination with an electrical charging system (1) comprising:

• a rectifier (6) to which energy being supplied from an external supply grid to an input (6a),
• the charging system (1) also comprising an inverter (3) whose alternating voltage side (3b) is electrically connected via phase conductors (u, v, w) to phase windings (U, V, W) of a rotating field machine (4) and whose direct voltage side (3a) being electrically connectable to an electrical energy accumulator (2) to be charged,
• a first current path section (7a) being formed for passing current supplied by the rectifier (6) into the charging system (1) by way of a plus pole of the rectifier (6) and the rotating field machine (4) to the inverter (3), and the first current path section (7a) causing the current to pass via the phase windings (U, V, W) of the rotating field machine (4),
• a minus terminal of the electrical energy accumulator (2) being electrically connected to a minus terminal of the rectifier (6) via an electrical pathway that bypasses both the inverter (3) and the rotating field machine (4),
• the first current path section (7a) comprising a first switch (S1), by which the first current path section (7a) being selectively interruptable, and
• the charging system (1) being designed such that by virtue of the first switch (S1) and at least one of the phase windings (U, V, W) in the first current path section (7a), the charging system (1) being operable as a step-up converter and also as a step-down converter in a direction toward the electrical energy accumulator (2).