The invention relates to an electrical drive system of a hybrid vehicle, comprising: a traction battery (1), a high-voltage intermediate circuit (2), a pulse-controlled inverter (3) which is coupled to the high voltage intermediate circuit (2), an electrical machine (5) which is coupled to the pulse-controlled inverter (3); a DC-to-DC converter (6) which is coupled to the pulse-controlled inverter (3) and the high-voltage intermediate circuit (2) and is designed to convert a high voltage (UE) from the high-voltage intermediate circuit (2) into a low voltage (UA) for a vehicle electrical system; a low-voltage battery (8) which is coupled to the DC-to-DC converter (6); a plurality of selectively-connectable electrical consumers (9a, 9b) of the vehicle electrical system, which are coupled to the low-voltage battery (8) and the DC-to-DC converter (6); and a control device (7) which, in the event of a traction battery failure, is designed to operate the DC-to-DC converter (6) in a current-controlled manner using the electrical machine so as to supply said vehicle electrical system consumers (9a, 9b).