Regenerative power supply unit and electric drive system

A regenerative power supply unit (1) is adapted to feed electrical energy from a DC intermediate circuit (2) in a three-phase network (3), wherein the regenerative power supply unit (1) comprising: a downconverter unit (4) having a first downconverter (5) and a second downconverter ( electrically 6), wherein the first buck converter (5) and the second buck converter (6) are connected in parallel and each input side (with the voltage intermediate circuit 2) are electrically coupled to an inverter (7), the input side (an output of the downconverter unit 4) is coupled and the output side with the three-phase network (3) is electrically coupled, at least one filter capacitor (CF; CF1, CF2, CF3), which is arranged at the output of downconverter unit (4) or at the output of the inverter (7), and a regulator unit (8) that is adapted in response to a filter capacitor current (iCF; iCF1, iCF2, ICF3) the first downconverter (5 ) And the second step-down converter (6) to control such that the first buck converter (5) and the second buck converter (6) equal parts (to an output current KIC) of the step-down converter unit (4) contribute.