On-board electrical system for a motor vehicle and method for operating an on-board electrical system for a motor vehicle

A method for operating an on-board electrical system for a motor vehicle, comprising:

• providing an on-board electrical system comprising:
• a first on-board electrical system having a first on-board electrical system voltage,
• a second on-board electrical system having:
• a second on-board electrical system voltage lower than the first on-board electrical system voltage, and two parallel strands and one electrical component connected to both strands,
• a first and a second DC-DC converter arranged between the first and the second on-board electrical systems, and
• an energy store arranged in the second on-board electrical system,
• supplying, in a normal operating mode, energy from the first on-board electrical system to the second on-board electrical system via the first and second DC-DC converters, and
• when a failure of one of the two parallel strands occurs, transitioning the on-board electrical system to a third fault mode in which the electrical component is supplied with energy via a remaining one of the two parallel strands, and, when a failure of one of the first or second DC-DC converters occurs, transitioning the on-board electrical system to a first fault mode in which the remaining one of the first or second DC-DC converters supplies the second on-board electrical system with energy, and, when a failure of both the first and second DC-DC converters or of the first on-board electrical system occurs, transitioning the on-board electrical system to a second fault mode in which the energy store supplies the second on-board electrical system with energy.

A method for operating an on-board electrical system of a motor vehicle, comprising:

• providing an on-board electrical system that includes:
• a first on-board electrical system,
• a second on-board electrical system coupled to the first on-board electrical system by a first DC-DC converter and a second DC-DC converter, and
• two parallel power strands in the second on-board electrical system, an electrical component being electrically connected to both power strands, and
• during normal operation, supplying energy from the first on-board electrical system to the second on-board electrical system through the first and second DC-DC converters, and
• when a failure of one of the two parallel power strands occurs, supplying the electrical component with energy via a remaining one of the two parallel power strands.