Monitoring device for leakage currents

Patent metadata

Field	Value
Publication number	US-11364810-B2
Application number	US-202017068984-A
Country	US
Kind code	B2
Filing date	Oct 13, 2020
Priority date	Oct 14, 2019
Publication date	Jun 21, 2022
Grant date	Jun 21, 2022

Abstract

A monitoring device for monitoring leakage currents at active conductors has a differential current measurement device, a signal generation device and a control device, which differential current measurement device is designed to record a first signal (I_DIFF) characterizing the differential current of the active conductors and to feed the first signal to the control device. The signal generation device is designed to generate at least one second signal (V_GRID) and to feed the second signal to the control device, which at least one second signal (V_GRID) includes information about the phase angle of a signal occurring at one of the active conductors. The control device is designed to generate a third signal (I_LC_RES) on the basis of the first signal (I_DIFF) and of the at least one second signal (V_GRID), which third signal characterizes the resistive leakage current.

First claim

What is claimed:

1. A monitoring device for monitoring leakage currents at active conductors, which active conductors are configured to be connected to a power grid by way of at least one phase conductor, said monitoring device comprising:
a control device;
a differential current measurement device configured to record a first signal (I_DIFF) characterizing a differential current of the active conductors and to feed said first signal to the control device;
a signal generation device configured to generate at least one second signal (V_GRID) and to feed said second signal to the control device, which at least one second signal (V_GRID) comprises information about a phase angle of a signal occurring at one of the active conductors; and
an amplifier and a feeder device,
wherein the amplifier is configured to generate a compensation current (I_COMP) on the basis of the fourth signal (I_COMP_S),
wherein the feeder device is configured to allow the compensation current to be fed in at least one of the active conductors,
wherein the control device is configured to generate a third signal (I_LC_RES) on the basis of the first signal (I_DIFF) and of the at least one second signal (V_GRID), which third signal characterizes a resistive leakage current, and
wherein the control device is configured to generate a fourth signal (I_COMP_S) from the first signal (I_DIFF) and from the second signal (V_GRID), which fourth signal characterizes the capacitive leakage current.

2. The monitoring device as claimed in claim 1 , wherein the control device is configured to compare the third signal (I_LC_RES) with a predefined first limit value (I_LC_RES_MAX) and then generate a fault signal (F_LC_RES_HIGH) when the third signal (I_LC_RES) corresponds to a resistive leakage current that is greater than the resistive leakage current corresponding to the first limit value (I_LC_RES_MAX).

3. The monitoring device as claimed in claim 2 , wherein the control device has an output interface and is configured to output the fault signal (F_LC_RES_HIGH) via the output interface.

4. The monitoring device as claimed in claim 2 , wherein the control device is configured to predefine the first limit value (I_LC_RES_MAX) on the basis of the second signal (V_GRID).

5. The monitoring device as claimed in claim 1 , wherein the signal generation device has at least one voltage measurement device and is configured to use the at least one voltage measurement device to generate a signal characterizing the voltage at the active conductor and to feed said signal to the control device as the second signal (V_GRID).

6. The monitoring device as claimed in claim 1 , wherein the signal generation device has at least one current measurement device and is configured to use the at least one current measurement device to generate a signal characterizing a current at the active conductor and to feed said signal to the control device as the second signal (V_GRID).

7. The monitoring device as claimed in claim 1 , wherein the control device is configured to define a phase position of the first signal (I_DIFF) in relation to the second signal (V_GRID) and, in order to define the third signal (I_LC_RES), to determine that component of the first signal (I_DIFF) that is in phase with the second signal (V_GRID).

8. The monitoring device as claimed in claim 1 , wherein the control device is configured to determine a first phase angle (phi 112 ; phi 113 ) from the first signal (I_DIFF) and to determine at least one second phase angle (phi 111 ) from the at least one second signal (V_GRID).

9. The monitoring device as claimed in claim 8 , wherein the control device is configured to define whether a resistive leakage current is present on the basis of the phase angle difference between the first phase angle (phi 112 ; phi 113 ) and the at least one second phase angle (phi 111 ).

10. The monitoring device as claimed in claim 1 , wherein the control device is configured to determine the third signal on the basis of a product of the first signal (I_DIFF) and the at least one second signal (V_GRID).

11. The monitoring device as claimed in claim 1 , wherein the signal generation device is configured to generate at least two second signals (V_GRID) and to feed said second signals to the control device, and wherein the control device is configured to generate the third signal (I_LC_RES) on the basis of the at least two second signals (V_GRID).

12. The monitoring device as claimed in claim 11 , wherein the control device is configured, when generating the third signal (I_LC_RES), to perform a respective individual comparison between the first signal (I_DIFF) and a first of the at least two second signals (V_GRID) and to check whether a resistive leakage current is present with regard to the first second signal (V_GRID).

13. A vehicle having a charger for a traction battery, which charger has a rectifier and a traction battery connected directly or indirectly to the rectifier, wherein the traction battery is coupled galvanically to the active conductors, and wherein the charger includes the monitoring device as claimed in claim 1 .

14. A monitoring device for monitoring leakage currents at active conductors, which active conductors are configured to be connected to a power grid by way of at least one phase conductor, said monitoring device comprising:
a control device;
a differential current measurement device configured to record a first signal (I_DIFF) characterizing a differential current of the active conductors and to feed said first signal to the control device; and
a signal generation device configured to generate at least two second signals (V_GRID) and to feed said second signals to the control device, which each second signal (V_GRID) comprises information about a phase angle of a signal occurring at one of the active conductors,
wherein the control device is configured to generate a third signal (I_LC_RES) on the basis of the first signal (I_DIFF) and of the at least two second signals (V_GRID), which third signal characterizes a resistive leakage current,
wherein the control device is configured, when generating the third signal (I_LC_RES), to perform a respective individual comparison between the first signal (I_DIFF) and a first of the at least two second signals (V_GRID) and to check whether a resistive leakage current is present with regard to the first second signal (V_GRID).

Assignees

• Porsche Ag

Inventors

• Spesser Daniel
• Pfizenmaier Tim

Classifications

• H02J2105/37

  exchanging power with electric vehicles [EV] or with hybrid electric vehicles [HEV] · CPC title

• H02J7/60

  including safety or protection arrangements · CPC title

• B60L3/0069

  relating to the isolation, e.g. ground fault or leak current · CPC title

• G01R31/52 Primary

  Testing for short-circuits, leakage current or ground faults · CPC title

• B60L53/30 Primary

  Constructional details of charging stations · CPC title