US 8,076,794 B2Granted

Multi-voltage vehicle electrical supply system for a motor vehicle and method for operating the same

AssigneeBayerische Motoren Werke Aktiengesellschaft

InventorsHartmut Proebstle, Michael Roesler, Joerg Merwerth, Thomas Christ

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Abstract

A multi-voltage vehicle electrical system for a motor vehicle is provided, including at least one multi-voltage generator, a first energy store, whose energy may be fed into a first low-voltage vehicle electrical system branch having low-voltage consumers, and a second energy store, whose energy may be fed into a second high-voltage vehicle electrical system branch having high-voltage consumers, as well as at least one controllable switching device, using which the energy generated by the multi-voltage generator may be distributed to the first and the second vehicle electrical system branches, the first and the second energy stores being connected in series to one another and the first vehicle electrical system branch being connected to a node between the first and the second energy store and to a reference potential of the first energy store.

Claims13

Dependent claims

A multi-voltage vehicle electrical system for a motor vehicle, comprising:

at least one multi-voltage generator;
a first energy store, whose energy is fed into a first low-voltage vehicle electrical system branch having low-voltage consumers;
a second energy store, whose energy is fed into a second high-voltage vehicle electrical system branch having high-voltage consumers;
and
a controllable switching device, using which the energy generated by the multi-voltage generator is distributed to the first and the second vehicle electrical system branches,
wherein the first and the second energy stores are connected in series to one another and the first vehicle electrical system branch is connected to a node between the first and the second energy stores and to a reference potential of the first energy store,
wherein the second vehicle electrical system branch is connected in parallel to the series circuit made of first and second energy stores,
wherein the controllable switching device being switchable between a first circuit configuration, in which the multi-voltage generator is in parallel to the first energy store and to the first vehicle electrical system branch, and a second circuit configuration, in which the multi-voltage generator is in parallel to the series circuit made of first and second energy stores and to the second vehicle electrical system branch,
wherein the first energy store is a battery and the second energy store is a super capacitor circuit,
wherein the controllable switching device comprises a first switchable interrupter between the terminal node of the first vehicle electrical system branch and the terminal of the multi-voltage generator facing away from its reference potential, and
wherein the first interrupter is opened when the charge state of the second energy store has fallen below a predetermined charge level, and the second energy store is charged when the first interrupter is opened.

8 more elements

A method for operating a multi-voltage vehicle electrical system including a multi-voltage generator delivering a selectable output voltage, a first energy store and a second energy store connected in series thereto, a first low-voltage electrical system branch connected in parallel to the first energy store, and a second high-voltage vehicle electrical system branch connected in parallel to the series circuit made of first and second energy stores, and a controllable switching device, using which the multi-voltage generator may alternatively be switched parallel to the first energy store or parallel to the series circuit made of first and second energy stores, wherein the controllable switching device comprises a first switchable interrupter between a terminal node of the first vehicle electrical system branch between first and second energy stores and the terminal of the multi-voltage generator facing away from its reference potential and a unidirectional disconnection unit, between the terminals of the multi-voltage generator and the second energy store facing away from their particular reference potentials, the method comprising the acts of:

preventing a current flow from the second to the first energy store if the first interrupter is dosed;
and
before the first interrupter is closed, equalizing the generator output voltage to the potential of the terminals of the first energy store facing away from its reference potential,
wherein the first energy store is a battery and the second energy store is a super capacitor circuit, and
wherein the first interrupter is opened when the charge state of the second energy store has fallen below a predetermined charge level, and the second energy store is charged when the first interrupter is opened.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 12/126,417Filed 23 May 2008 · continuation
Priority: DE 10 2005 056 23225 Nov 2005
Published: US 2008/0284246 A120 Nov 2008
Granted: 13 Dec 2011
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

H02J 7/1423
For charging batteries from dynamo-electric generators driven at varying speed, e.g. on vehicle: with multiple batteries
B60L 58/20
Of two or more battery modules: having different nominal voltages
Y02T 10/70
Other road transportation technologies with climate change mitigation effect: energy storage systems for electromobility, e.g. batteries
H02J
Power supply and charging