On-board electrical system and method for a motor vehicle

Abstract

The invention relates to an on-board electrical system (1) for a motor vehicle, comprising at least one HV battery (2) for providing a positive potential (H+) and a negative potential (H-) and at least one HV consumer (3, 4), wherein: an insulation monitor (5) is provided for monitoring the insulation resistance (R iso_P , R iso_N ) to a vehicle ground (PA) which is electrically isolated from the on-board electrical system (1); a Y-capacitance (C Y_P , C Y_N ) is provided between the positive potential (H+) and the vehicle ground (PA) and between the negative potential (H-) and the vehicle ground (PA), respectively; a voltage center tap (6) between the positive potential (H+) and the negative potential (H-) present in the on-board electrical system (1) or in a component of the on-board electrical system (1) is connected to the vehicle ground (PA) via an ohmic coupling resistance (R K ).

Claims

1. An onboard electrical network (1) for a motor vehicle, comprising at least one high-voltage battery (2) for providing a positive potential (H+) and a negative potential (H-) and at least one high-voltage power consumer (3, 4), wherein, An insulation monitor (5) is provided to monitor the insulation resistance (R) of the vehicle ground (PA), which is electrically isolated from the vehicle electrical grid (1). iso_P R iso_N The Y capacitor (C) is provided between the positive potential (H+) and the vehicle ground (PA) and between the negative potential (H-) and the vehicle ground (PA). Y_P C Y_N ), Its features are, A voltage center tap (6) exists in the vehicle electrical network (1) or in a component of the vehicle electrical network (1). The voltage center tap (6) is located between two resistors connected as a voltage divider between the positive potential (H+) and the negative potential (H-), or is formed by a capacitive voltage divider and connected through an ohmic coupling resistor (R). K ) connected to the vehicle ground (PA), Wherein, the coupling resistor (R) K ) is formed by a fixed resistor (R) F ) and variable resistor (R) V A series circuit consisting of .

2. The vehicle-mounted electrical grid according to claim 1, Its features are, The resistor of the voltage divider is formed as the internal resistance of a series high-voltage power consumer (3, 4) or at least two series high-voltage batteries (2.1, 2.2).

3. The vehicle-mounted electrical grid (1) according to claim 2, Its features are, The voltage divider's resistance and the coupling resistor (R) K The measuring resistance (R) of the insulation monitor (5) configured as a resistance insulation monitor. mess_p R mess_n It is much smaller in comparison.

4. The vehicle-mounted electrical grid (1) according to claim 3, Its features are, The measured resistance (R) mess_p R mess_n ) and the coupling resistor (R) K (In the range of more than 100 kOhm) 5. The vehicle-mounted electrical network (1) according to any one of the preceding claims, Its features are, At least one of the following lists is connected through the coupling resistor (R) K Coupled to the vehicle ground (PA): - A series circuit for the high-voltage power supply of the control board. - Series circuits of half-bridge and / or H-bridge, - Multi-level half-bridge, - The series circuit of the inverter. - Multilevel inverter - A heating circuit with two or more heating elements connected in series. - Taps at the connection points of the battery module series circuit.

6. A vehicle comprising an onboard electrical network (1) according to any one of the preceding claims.

7. A method for operating the vehicle according to claim 6, Its features are, The coupling resistor (R) K ) is formed by the fixed resistor (R) F ) and the variable resistor (R) V A series circuit consisting of [variable resistors] is used when the vehicle is not connected to a DC charging station, and a high variable resistor (R) is provided. V When the vehicle is connected to a DC charging station, a low variable resistor (R) is set. V ).

Images