Adaptive filter with Y capacitors for a 3-phase DC on-board electrical system
Power converter having first, second and third lines, and a filter device having a first terminal connected to the first line, second terminal connected to the second line, and a third terminal connected to the third line. A first capacitor is provided via which a first current path is routed from the first terminal to the third terminal, a second capacitor via which a second current path is routed from the second terminal to the third terminal, a third capacitor connected between a center node, which is between the first capacitor and the second capacitor, and the third terminal. A switching device switches between a first filter mode, in which the first and second current paths are routed past the third capacitor to the third terminal, and a second filter mode, in which the first and second current paths are routed via the third capacitor to the third terminal.
1 . A power converter for an on-board electrical system of an electrically driveable vehicle, having a first line for a first potential, a second line for a second potential, a third line for a reference potential and a filter device that has
a first terminal that is connected to the first line,
a second terminal that is connected to the second line,
a third terminal that is connected to the third line,
a first capacitor via which a first current path is routed from the first terminal to the third terminal,
a second capacitor via which a second current path is routed from the second terminal to the third terminal, and
a switching device that is configured to switch between a first filter mode and a second filter mode on the basis of control information,
wherein
the filter device further has a third capacitor that forms an electrically conductive connection between a center node, which is between the first capacitor and the second capacitor, and the third terminal, wherein the first current path and the second current path are routed past the third capacitor to the third terminal in the first filter mode and are routed via the third capacitor to the third terminal in the second filter mode.
2 . The power converter as claimed in claim 1 , wherein
the filter device is configured, in the second filter mode, to set in each case a higher pole frequency for filtering a common-mode current on the first line and the second line along the first current path and the second current path than in the first filter mode.
3 . The power converter as claimed in claim 2 , wherein
the center node is a common node of
a terminal of the third capacitor facing away from the third terminal,
a terminal of the first capacitor facing away from the first terminal and/or facing the second capacitor, and
a terminal of the second capacitor facing away from the second terminal and/or facing the first capacitor.
4 . The power converter as claimed in claim 2 , wherein
a terminal of the third capacitor facing away from the center node is connected to the third terminal.
5 . The power converter as claimed in claim 2 , wherein
the switching device has a first terminal and a second terminal and a switching path able to be controlled on the basis of the control information.
6 . The power converter as claimed in claim 1 , wherein
the center node is a common node of
a terminal of the third capacitor facing away from the third terminal,
a terminal of the first capacitor facing away from the first terminal and/or facing the second capacitor, and
a terminal of the second capacitor facing away from the second terminal and/or facing the first capacitor.
7 . The power converter as claimed in claim 1 , wherein
a terminal of the third capacitor facing away from the center node is connected to the third terminal.
8 . The power converter as claimed in claim 1 , wherein
the switching device has a first terminal and a second terminal and a switching path able to be controlled on the basis of the control information.
9 . The power converter as claimed in claim 8 , wherein
the first terminal of the switching device is connected to the center node and/or to the third capacitor.
10 . The power converter as claimed in claim 9 , wherein
the second terminal of the switching device is connected to the third terminal of the filter device and/or to the third capacitor.
11 . The power converter as claimed in claim 9 , wherein
the switching device is configured to switch on the switching path so as to adopt the first filter mode and/or to switch it off so as to adopt the second filter mode.
12 . The power converter as claimed in claim 8 , wherein
the second terminal of the switching device is connected to the third terminal of the filter device and/or to the third capacitor.
13 . The power converter as claimed in claim 8 , wherein
the switching device is configured to switch on the switching path so as to adopt the first filter mode and/or to switch it off so as to adopt the second filter mode.
14 . The power converter as claimed in claim 1 , wherein
the switching device is connected in parallel with the third capacitor.
15 . The power converter as claimed in claim 1 , wherein
the switching device is designed as a bidirectionally conductive and/or blocking switch.
16 . The power converter as claimed in claim 1 , wherein
the capacitance of the third capacitor is less than the capacitance of the first capacitor and/or of the second capacitor, and/or
the capacitances of the first capacitor and of the second capacitor are the same.
17 . The power converter as claimed in claim 1 , wherein
the filter device further has a fourth capacitor that is connected to the first terminal of the filter device and to the second terminal of the filter device in parallel with the first capacitor and with the second capacitor.
18 . The power converter as claimed in claim 1 , wherein
the filter device has a printed circuit board, wherein
the first to third capacitors, in particular also a fourth capacitor, are arranged on the printed circuit board and/or
the first to third terminals of the filter device are arranged on the printed circuit board and/or
the switching device is arranged on the printed circuit board.
19 . The power converter as claimed in claim 1 , further comprising
a DC link capacitor, which is connected between the first line and the second line, and a converter circuit, which is connected between the first line and the second line, wherein the filter device is arranged on a side of the DC link capacitor facing away from the converter circuit.
20 . An onboard electrical system for an electrically driveable vehicle, having
at least one power converter as claimed in claim 1 , a traction battery, a charging device that is able to be connected to an electrical power supply system external to the vehicle in order to charge or discharge the traction battery, and a control device that is configured to provide the control information to adopt the second filter mode when and/or for as long as the charging device is connected to the electrical power supply system external to the vehicle.