Vehicle electrical system and method for operating a vehicle electrical system
View Patent ↗A vehicle electrical system includes a first system branch with a first nominal voltage U 1 , a second system branch with a second nominal voltage U2, at least one DC/DC converter configured to transmit energy between the first and second system branches, a first actuating unit to actuate the DC/DC converter(s), a first detection unit to detect an instantaneous voltage U act,1 of the first system branch, and a comparison unit to compare the detected instantaneous voltage U act,1 to a first upper voltage threshold value U o,1 and to a first lower voltage threshold value U u,1 , wherein U u,1 <U 1 <U o,1 . The first actuating unit actuates the DC/DC converter(s) such that energy is transmitted from the first system branch to the second system branch if U act,1 >U o,1 , and such that energy is transmitted from the second system branch to the first system branch if U act,1 <U u,1 .
1. A vehicle electrical system, comprising:
a first vehicle electrical system branch with a first nominal voltage U1,
a second vehicle electrical system branch with a second nominal voltage U2,
at least one DC/DC converter configured to transfer energy between the first vehicle electrical system branch and the second vehicle electrical system branch,
a first actuating unit configured to actuate the at least one DC/DC converter,
a first detection unit configured to detect an instantaneous voltage Uact, 1 of the first vehicle electrical system branch, and
a first comparison unit configured to compare the detected instantaneous voltage Uact,1 with a first upper voltage threshold value Uo,1 and a first lower voltage threshold value Uu,1, where Uu,1<U1<Uo,1,
wherein the first actuating unit is configured to actuate the at least one DC/DC converter such that energy is transferred from the first vehicle electrical system branch to the second vehicle electrical system branch if Uact,1>Uo,1, and such energy is transferred from the second vehicle electrical system branch to the first vehicle electrical system branch if Uact,1<Uu,1,
wherein if Uact,1>Uo,1, after the actuation of the at least one DC/DC converter:
the first detection unit detects a second value of the instantaneous voltage Uact,1 of the first vehicle electrical system branch,
the first comparison unit compares the detected second value of the instantaneous voltage Uact,1 with a second upper voltage threshold value Uo,2, where U1<Uo,2<Uo,1, and
if Uact,1<Uo,2, the first actuation unit ends the transfer of energy from the first vehicle electrical system branch to the second vehicle electrical system branch, and
wherein if Uact,1<Uu,1, after the actuation of the at least one DC/DC converter:
the first detection unit detects a second value of the instantaneous voltage Uact,1 of the first vehicle electrical system branch,
the first comparison unit compares the detected second value of the instantaneous voltage Uact,1 with a second lower voltage threshold value Uu,2, where Uu,1<Uu,2<U1, and
if Uact,1>Uu,2, the first actuation unit ends the transfer of energy from the second vehicle electrical system branch to the first vehicle electrical system branch.
2. The vehicle electrical system of claim 1 , wherein the first comparison unit has at least one comparator.
3. The vehicle electrical system of claim 1 , further comprising a voltage-limiting switch.
4. The vehicle electrical system of claim 3 , wherein the voltage-limiting switch has at least one freewheeling diode.
5. The vehicle electrical system of claim 1 , further comprising:
a second detection unit configured to detect an instantaneous voltage Uact,2 of the second vehicle electrical system branch, and
a second comparison unit configured to compare the detected instantaneous voltage Uact,2 with a third upper voltage threshold value Uo,3 and a third lower voltage threshold value Uu,3, where Uu,3<U2<U0,3.
6. The vehicle electrical system of claim 5 , wherein the first actuating unit is further configured to actuate the at least one DC/DC converter such that energy is transferred from the second vehicle electrical system branch to the first vehicle electrical system branch if Uact,2>U0,3, and such that energy is transferred from the first vehicle electrical system branch to the second vehicle electrical system branch if Uact,2<Uu,3.
7. The vehicle electrical system of claim 1 , wherein the at least one DC/DC converter comprises a synchronous converter.
8. A vehicle comprising:
a vehicle electrical system comprising:
a first vehicle electrical system branch with a first nominal voltage U1,
a second vehicle electrical system branch with a second nominal voltage U2,
at least one DC/DC converter configured to transfer energy between the first vehicle electrical system branch and the second vehicle electrical system branch,
a first actuating unit configured to actuate the at least one DC/DC converter,
a first detection unit configured to detect an instantaneous voltage Uact, 1 of the first vehicle electrical system branch, and
a first comparison unit configured to compare the detected instantaneous voltage Uact,1 with a first upper voltage threshold value Uo,1 and a first lower voltage threshold value Uu,1, where Uu,1<U1<U0,1,
wherein the first actuating unit is configured to actuate the at least one DC/DC converter such that energy is transferred from the first vehicle electrical system branch to the second vehicle electrical system branch if Uact,1>Uo,1, and such energy is transferred from the second vehicle electrical system branch to the first vehicle electrical system branch if Uact,1<Uu,1,
wherein if Uact,1>Uo,1, after the actuation of the at least one DC/DC converter:
the first detection unit detects a second value of the instantaneous voltage Uact,1 of the first vehicle electrical system branch,
the first comparison unit compares the detected second value of the instantaneous voltage Uact,1 with a second upper voltage threshold value Uo,2, where U1<Uo,2<Uo,1, and
if Uact,1<Uo,2, the first actuation unit ends the transfer of energy from the first vehicle electrical system branch to the second vehicle electrical system branch, and
wherein if Uact,1<Uu,1, after the actuation of the at least one DC/DC converter:
the first detection unit detects a second value of the instantaneous voltage Uact,1 of the first vehicle electrical system branch,
the first comparison unit compares the detected second value of the instantaneous voltage Uact,1 with a second lower voltage threshold value Uu,2, where Uu,1<Uu,2<U1, and
if Uact,1>Uu,2, the first actuation unit ends the transfer of energy from the second vehicle electrical system branch to the first vehicle electrical system branch.
9. A method for operating a vehicle electrical system having a first vehicle electrical system branch with a first nominal voltage U1, a second vehicle electrical system branch with a second nominal voltage U2, and at least one DC/DC converter configured to transfer energy between the first vehicle electrical system branch and the second vehicle electrical system branch, the method comprising:
detecting a first value of an instantaneous voltage Uact,1 of the first vehicle electrical system branch,
comparing the detected first value of the instantaneous voltage Uact,1 with a first upper voltage threshold value Uo,1 and a first lower voltage threshold value Uu,1, where Uu,1<U1<Uo,1, and
if Uact,1>Uo,1, actuating the at least one DC/DC converter such that energy is transferred from the first vehicle electrical system branch to the second vehicle electrical system branch, and if Uact,1<Uu,1, actuating the at least one DC/DC converter such that energy is transferred from the second vehicle electrical system branch to the first vehicle electrical system branch,
wherein if Uact,1>Uo,1, the method further comprises, after the actuation of the at least one DC/DC converter:
detecting a second value of the instantaneous voltage Uact,1 of the first vehicle electrical system branch,
comparing the detected second value of the instantaneous voltage Uact,1 with a second upper voltage threshold value Uo,2, where U1<Uo,2<Uo,1, and
if Uact,1<Uo,2, ending the transfer of energy from the first vehicle electrical system branch to the second vehicle electrical system branch, and
if Uact,1<Uu,1 the method further comprises, after the actuation of the at least one DC/DC converter:
detecting a second value of the instantaneous voltage Uact,1 of the first vehicle electrical system branch,
comparing the detected second value of the instantaneous voltage Uact,1 with a second lower voltage threshold value Uu,2, where Uu,1<Uu,2<U1, and
if Uact,1>Uu,2 ending the transfer of energy from the second vehicle electrical system branch to the first vehicle electrical system branch.
10. The method of claim 9 , wherein if Uact,1>Uo,1 the transfer of energy from the first vehicle electrical system branch to the second vehicle electrical system branch is ended after a predetermined time period.
11. The method of claim 9 , wherein if Uact,1<Uu,1 the transfer of energy from the second vehicle electrical system branch to the first vehicle electrical system branch is ended after a predetermined time period.