On-board electrical system for a vehicle and also control apparatus for an on-board electrical system
An electrical system has first and second switches. The switches are used by the electrical system to produce closed circuits from a first energy storage device and/or a second energy storage device to a system load to supply power to the system load. The electrical system has a device for detecting a voltage at the second energy storage device and for comparing the detected voltage with a voltage threshold, and also a control device for producing a third, closed circuit from the second energy storage device to an earth connection by closing the first and second switches, and therefore for discharging the second energy storage device when the detected voltage exceeds the voltage threshold. This prevents the second energy storage device from charging uncontrollably when a system fault occurs in the electrical system or on the current path from the first energy storage device to the second energy storage device.
1. An on-board electrical system for a vehicle, comprising:
a system load having at least one power consumer;
a first energy store providing current for said system load;
a second energy store providing current for said system load, said second energy store being rechargeable;
a first, controllable switch, producing a first, closed circuit from said first energy store to said system load in a closed switching state;
a second, controllable switch, producing a second closed circuit from said first energy store via said second energy store to said system load in a closed switching state;
a monitoring device for detecting a voltage value at said second energy store and for comparing a detected voltage value with a predetermined voltage threshold value; and
a control device for producing a third, closed circuit from said second energy store via said first switch and said second switch, to an electrical ground, by closing said first switch and said second switch and therefore for discharging said second energy store when the detected voltage value exceeds the predetermined voltage threshold value.
2. The on-board electrical system according to claim 1 , further comprising a recharging device for charging said second energy store with a charging current from said first energy store.
3. The on-board electrical system according to claim 2 , wherein said control device configured to discharge the charging current via said first, controllable switch and said second, controllable switch to said electrical ground when the detected voltage value exceeds the predetermined voltage threshold value.
4. The on-board electrical system according to claim 1 , wherein said monitoring device predetermines the predetermined voltage threshold value depending on at least one parameter related to a charge capacity of said second energy store.
5. The on-board electrical system according to claim 1 , wherein said control device keeps said first, controllable switch and said second, controllable switch in the closed switching state for a predetermined period of time, wherein said control device predetermines the predetermined period of time depending on the detected voltage value in comparison with the predetermined voltage threshold value.
6. A control apparatus for controlling a current flow in an on-board electrical system, the control apparatus comprising:
a first electrical terminal, a second electrical terminal and a third electrical terminal for producing electrical connections between the control apparatus and the on-board electrical system;
a first controllable switch, disposed between said first terminal and said second terminal and electrically connecting said first terminal to said second terminal in a closed switching state;
a second controllable switch, disposed between said first terminal and said third terminal and electrically connecting said first terminal to said third terminal in a closed switching state;
a monitoring device for detecting a voltage value between said third terminal and said second terminal and for comparing a detected voltage value with a predetermined voltage threshold value; and
a control device for closing said first controllable switch and said second controllable switch or for holding said first controllable switch and said second controllable switch in the closed switching state when the detected voltage value exceeds the predetermined voltage threshold value.
7. A vehicle with an on-board electrical system, comprising:
an on-board electrical system containing:
a system load having at least one power consumer;
a first energy store providing current for said system load;
a second energy store providing current for said system load, said second energy store being rechargeable;
a first, controllable switch, producing a first, closed circuit from said first energy store to said system load in a closed switching state;
a second, controllable switch, producing a second closed circuit from said first energy store via said second energy store to said system load in a closed switching state;
a monitoring device for detecting a voltage value at said second energy store and for comparing a detected voltage value with a predetermined voltage threshold value; and
a control device for producing a third, closed circuit from said second energy store via said first switch and said second switch, to an electrical ground, by closing said first switch and said second switch and therefore for discharging said second energy store when the detected voltage value exceeds the predetermined voltage threshold value.