METHOD FOR VOLTAGE REGULATION OF AN ELECTRICAL SYSTEM OF A MOTOR VEHICLE

The invention relates to a method for supplying voltage to an on-board electrical system (1) of a motor vehicle, comprising a first sub-network (2) in which a first rated voltage (U1) is applied and which includes a first energy storage device (5) for electrical energy and a load resistance formed by at least one consumer (9), and a second sub-network (3) in which a second rated voltage (U2) is applied and which includes an electric machine (8) operable in both motor and generator modes and a second energy storage device (6) for electrical energy, wherein the first and second sub-networks (2, 3) are coupled to one another via a first DC/DC converter (4). The method comprises the following steps: (a) During driving operation: supplying the first sub-network (2) with voltage from the second sub-network (3) via the first DC/DC converter (4), wherein the first energy storage device (5) is used to cover load peaks; (b) during non-driving operation: supplying the first sub-network (2) with voltage via the first energy storage device (5); and (c) recharging the first energy storage device (5) with energy from the second energy storage device (6) during non-driving operation, wherein the recharging of the first energy storage device (5) occurs periodically and/or when a monitored parameter, which is a measure of the state of charge of the first energy storage device (5), indicates a drop below a specified minimum state of charge of the first energy storage device (5).