Method for the detection of an arc fault in an electrical circuitry, and motor vehicle

Patent metadata

Field	Value
Publication number	US-12062900-B2
Application number	US-202117509928-A
Country	US
Kind code	B2
Filing date	Oct 25, 2021
Priority date	Oct 26, 2020
Publication date	Aug 13, 2024
Grant date	Aug 13, 2024

Abstract

A method detects an arc fault in an electrical circuitry. The electrical circuitry includes a controller, an energy storage and a plurality of loads each connected to the energy storage via a respective load path. A current measuring device determines current measurement values describing an energy storage current is assigned to the energy storage. Voltage measuring devices for determining voltage measurement values describing a load voltage at the respective load are assigned to said loads. The current measurement values and voltage measurement values are continuously transmitted to the controller via at least one communication link.

First claim

The invention claimed is:

1. A method for detecting an arc fault in an electrical circuitry including a switching device electrically coupled between plurality of loads and an energy storage that stores energy, the method comprising:
determining, with a current measuring device electrically coupled between the energy storage and the switching device of the electrical circuitry, current measurement values indicative of an energy storage current between the energy storage and a plurality of loads of the electrical circuitry, wherein the current measuring values include, for each time interval of a plurality time intervals, a mean value of the energy storage current and a maximum value of the energy storage current;
determining, for each load of the plurality of loads of the electrical circuitry, voltage measurement values indicative of a load voltage at the load with a respective voltage measuring device electrically coupled to the load, wherein each load is connected to the energy storage by a respective load path;
continuously transmitting the current measurement values and the voltage measurement values to a controller of the electrical circuitry via at least one communication link, wherein a sampling frequency of the current measuring device is higher than a transmission frequency of the current measurement values from the current measuring device to the controller;
detecting a parallel arc in the electrical circuitry by comparing the current measurement values or a change over time of the energy storage current indicated by the current measurement values with at least one current limit value;
detecting a series arc in one of the load paths by comparing the voltage measurement values or a change over time of the load voltages of the load associated with the load path indicated by the voltage measurement values with at least one voltage limit value assigned to the respective load; and
disconnecting, via the switching device, the energy storage from the load associated with the one of the load paths responsive to detecting the parallel arc or switching off the load associated with the one of the load paths responsive to detecting an occurrence of the series arc in the one of the load paths.

2. The method according to claim 1 , wherein each current measurement value is a mean value of the energy storage current representing a measurement of a total current flow from a respective time interval, wherein a change over time in the mean values is compared with a mean value limit value as the current limit value.

3. The method according to claim 2 , wherein the communication link is a data bus, wherein the time interval corresponds to the time between two transmission time slots in which the current measuring device sends at least one current measurement value to the controller.

4. The method according to claim 1 , wherein each current measurement value is a maximum value of the energy storage current in a respective time interval, wherein a change over time in the maximum values is compared with a maximum value limit value as the current limit value.

5. The method according to claim 1 , wherein the controller, in operation, for each time interval of the plurality time intervals, compares a difference between the mean value and the maximum value with a differential limit value as the current limit value.

6. The method according to claim 1 , comprising disconnecting the energy storage from the loads when the current measurement values or the change over time of the energy storage current indicated by the current measurement values exceed the at least one current limit value.

7. The method according to claim 1 , further comprising:
determining, for each load, at least one respective reference differential voltage between a voltage measurement value of the load and a reference voltage value of the energy storage; and
comparing, for each load, the at least one respective reference differential voltage with a reference differential limit value assigned to the load.

8. The method according to claim 7 , further comprising:
determining, for each load, at least one load differential voltage between a voltage measurement value of the load and at least one voltage measurement value of at least another one of the loads; and
comparing, for each load, the load differential voltage with a load differential limit value assigned to the load.

9. The method according to claim 8 , further comprising:
comparing, for each load, the change over time of the load voltage with a load voltage limit value assigned to the load; and
switching off each load when the corresponding at least one respective reference differential voltage exceeds the reference differential limit value assigned to the load, the corresponding load differential voltage exceeds the load differential limit value, and the corresponding change over time of the load voltage exceeds the load voltage limit value.

10. The method according to claim 1 , comprising detecting the series arc when the voltage measurement values or the change over time of the load voltages of the load associated with the load path indicated by the voltage measurement values exceeds the at least one voltage limit value for a predetermined time period or for a predetermined number of consecutive voltage measurements.

11. The method according to claim 1 , comprising determining the current measurement values or the voltage measurement values with a frequency between 50 Hz and 20 kHz.

12. The method according to claim 1 , comprising:
transmitting the voltage measurement values for each load at at least partially different times via the communication link; and
synchronizing the voltage measurement values with the controller.

13. The method according to claim 1 , further comprising controlling, with the controller, a flow of energy between the energy storage and at least one of the loads.

14. The method according to claim 1 , wherein the electrical circuitry includes an onboard electrical system of a motor vehicle with a voltage of 48 V, wherein at least one of the loads includes an electrical consumer of a motor vehicle selected from a group including an inverter, a drive train generator, a starter generator, an electrically operated catalytic converter, an electric drive compressor and an electric refrigerant compressor.

15. The method according to claim 1 , wherein the electrical circuitry includes a respective switch different from the switching device in each respective load path, and wherein the controller, in operation, switches off the respective switch in the one of the load paths to switch off the load associated with the one of the load paths responsive to detecting the occurrence of the series arc in the one of the load paths.

16. A motor vehicle, comprising:
electrical circuitry including:
a controller;
an energy storage that, in operation, stores energy;
a plurality of loads each connected to the energy storage via a respective load path;
a switching device electrically coupled between the energy storage and the plurality of loads;

a current measuring device electrically coupled between the switching device and the energy storage that, in operation, stores energy,
wherein the current measuring device, in operation, determines current measurement values indicative of an energy storage current between the energy storage and a plurality of loads of the electrical circuitry, wherein the current measurement values include, for each time interval of a plurality time intervals, a mean value of the energy storage current and a maximum value of the energy storage current; an

Assignees

• Audi Ag

Inventors

• Kell Viktor

Classifications

• H02H3/08

  responsive to excess current (responsive to abnormal temperature caused by excess current H02H5/04) · CPC title

• H02P29/024

  Detecting a fault condition, e.g. short circuit, locked rotor, open circuit or loss of load · CPC title

• G01R19/16571

  comparing AC or DC current with one threshold, e.g. load current, over-current, surge current or fault current (G01R19/16514, G01R19/16519, G01R19/16528, G01R19/16533, G01R19/1659 take precedence; measuring currents by using elements sensitive to the magnetic field generated G01R15/14; measuring earth resistance G01R27/18; testing for leakage or short circuits in electrical apparatus G01R31/52) · CPC title

• G01R31/006

  on road vehicles, e.g. automobiles or trucks (testing of ignition installations peculiar to internal combustion engines F02P17/00) · CPC title

• G01R31/1272 Primary

  of cable, line or wire insulation, e.g. using partial discharge measurements (locating faults in cables G01R31/083) · CPC title