A power supply assembly for a vehicle includes a generator connected to an engine of the vehicle; a high-voltage bus to which the output voltage of the generator is supplied and to which a high-voltage load is connected; a low-voltage bus connected to the high-voltage bus via a voltage step-down element and to which a starter motor and a low-voltage load are connected; a high-voltage storage cell which a positive terminal thereof is connected to the high-voltage bus and a negative terminal thereof is grounded via a switch element; a low-voltage storage cell which a positive terminal thereof is connected to the low-voltage bus via a key switch and a negative terminal thereof is grounded; and a controller for controlling the opening and closing of the switch element, wherein the controller is constructed so as to monitor the starting and stopping of the engine based on start and stop signals form the engine, and open the switch element when the stopping of the engine is detected.

In an energy supply circuit for a motor vehicle on-board electrical system with two voltage supply branches at different voltage levels, the first voltage supply branch can be fed by way of an electric direct voltage converter by the second voltage supply branch and the second voltage supply branch can be fed by a generator. A multi-level controller W3 with three voltage levels is provided whose first in/output is connected with the second voltage supply branch, whose second in/output is connected with the first voltage supply branch and whose third in/output is connected with the energy accumulator B1 assigned to the first voltage supply branch.

A vehicle regenerative braking apparatus of simple structure is provided, which prevents adverse effects on a battery while handling excess power appropriately. In a vehicle regenerative braking, when excess power which exceeds a preferable charge amount of a battery has been generated as a result of regeneration, the excess power is consumed by increased power consumption of a plurality of electrical loads selected from among several electrical loads.

A device for voltage regulation for a generator driven by an internal combustion engine is described in which the voltage regulator is equipped with a load response travel function (LRF), which prevents a rapid rise in the exciting current when a powerful electric consumer is turned on. By means of a suitable trigger circuit which evaluates the engine rpm and thus the generator rpm, the load response travel function is blocked during travel when rpm values are falling, so that in this case, the voltage incursions that occur during an active load-response function are maximally averted.

A generator control system for a vehicle includes an AC generator, a switch connected in series with a field coil, a voltage regulator unit, a field-current restricting unit for controlling the switch to turn on or off, a forbidding unit having a command signal input terminal for forbidding operation of the field-current restricting unit when a voltage higher than a predetermined regulation voltage is applied to the command signal input terminal.