METHOD FOR OPERATING A VEHICLE-EXTERNAL CHARGING DEVICE FOR CHARGING A VEHICLE AND CHARGING DEVICE

Abstract

A method is provided for operating a vehicle-external charging device (1) for charging an electric or hybrid vehicle. The method checks an electrical connection of an insulation monitor (3) between a contactor (4) of the charging device (1) and a charging cable (5) of the charging device (1) when the contactor (4) is in a closed switching state and also uses the insulation monitor to check an electrical insulation of the charging cable (5) when the contactor (4) is in an open switching state. A charging device (1) also is provided.

Claims

1. A method for operating a vehicle-external charging device for charging an electric or hybrid vehicle, the method comprising: checking an electrical connection of an insulation monitor that is connected between a contactor of the charging device and a charging cable of the charging device when the contactor is in a closed switching state; and using the insulation monitor to check an electrical insulation of the charging cable when the contactor is in an open switching state.

2. The method of claim 1, wherein the correct connection of the insulation monitor is checked by the insulation monitor.

3. The method of claim 1, wherein the switching state of the contactor is transmitted from a positively driven auxiliary contact of the contactor via a signal line to the insulation monitor.

4. The method of claim 1, wherein the switching state of the contactor is transmitted from a control computer of the charging device to the insulation monitor.

5. The method of claim 1, further comprising using the insulation monitor to check an electrical insulation of the charging device between the contactor and a power electronics system when the contactor is in an open switching state.

6. The method of claim 5, further comprising checking a further electrical connection of the insulation monitor between the contactor and the power electronics system when the contactor is in an open switching state.

7. The method of claim 5, further comprising checking the electrical insulation of the charging cable at first connections of the insulation monitor, checking the electrical insulation of the charging device between the contactor and the power electronics system at second connections of the insulation monitor, and in the closed switching state of the contactor comparing measurement values at the first connections with measurement values at the second connections.

8. The method of claim 1, further comprising using the insulation monitor to monitor a voltage between electrical lines of the charging cable and to monitor a further voltage between electrical lines between the contactor and the power electronics system.

9. The method of claim 1, wherein the steps of checking the electrical connection of the insulation monitor and checking the electrical insulation of the charging cable are carried out based on reference values, wherein the reference values are provided to the insulation monitor as a value matrix and are updated in the event of a charging process.

10. A charging device for charging an electric or hybrid vehicle, the charging device comprising: a contactor; a charging cable and an insulation monitor that is connected between the contactor and the charging cable, the insulation monitor being configured to check an electrical connection of the insulation monitor to the contactor and to the charging cable when the contactor is in a closed switching state and to check an electrical insulation of the charging cable when the contactor is in an open switching state.

11. The charging device of claim 10, wherein the insulation monitor further is connected between the contactor and a power electronics system of the charging device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG. 1 schematically illustrates a charging device according to an embodiment of the invention that is operated according to the method of the invention.

DETAILED DESCRIPTION

[0023] FIG. 1 schematically illustrates a charging device 1 according to an embodiment of the invention. The charging device is operated according to the method of the invention. The charging device 1 is a vehicle-external charging device 1 for charging a vehicle 2 having an electric drive. The vehicle 2 is connected to the charging device 1 using a charging cable 5. A contactor 4 is arranged between a power electronics system 7 of the charging device 1 and the charging cable 5. In the closed switching state, the contactor 4 electrically connects the power electronics system 7 to the charging cable 5 and, in the open switching state, the contactor 4 interrupts the connection between the charging cable 5 and the power electronics system 7.

[0024] The charging device 1 has an insulation monitor 3 arranged between the contactor 4 and the charging cable 5. The insulation monitor 3 monitors the electrical insulation of lines to which it is connected and ensures safe charging of the vehicle 2. The insulation monitor 3 checks for a correct connection that will ensure correct functioning of the insulation monitoring system. For this purpose, the insulation monitor carries out a resistance measurement at the electrical lines that are to be monitored. However, this is only possible for resistances that are lower than, for example, 4 MOhm.

[0025] It also is desirable for the insulation of the charging cable 5 to be checked when no vehicle 2 is being charged, that is to say when the charging cable 5 has an open end and thus an infinitely high resistance. In such a case, the correct connection of the insulation monitor 3 cannot be checked. However, in accordance with the invention, the connection is checked depending on the switching state of the contactor 4. If the switching state of the contactor 4 is closed, that is to say a charging process is currently taking place, the resistance of the charging cable is below, for example, 4 MOhm, and the correct electrical connection can be checked. If this is determined, the electrical insulation of the charging cable 5 can also be monitored between the charging processes as well.

[0026] Information about the switching state of the contactor 4 are obtained by the insulation monitor 3 via a signal line 6 that connects a positively driven auxiliary contact of the contactor to the insulation monitor 3. It is possible that a control computer transmits items of information about the switching state to the insulation monitor 3.

[0027] In the context of this disclosure, a “control computer” can be understood to include, for example, a processor and/or a storage unit or memory for storing algorithms and program commands. By way of example, the processor and/or the evaluation unit is specifically configured to carry out program commands in such a way that the processor and/or the control computer carries out functions to implement or realize a method as disclosed herein or a step of a method as disclosed herein. The term control computer is used here synonymously with devices known from the prior art and therefore, encompasses one or more general-purpose processors (CPUs) or microprocessors, RISC processors, GPUs and/or DSPs. The control computer has, for example, additional elements such as storage interfaces or communication interfaces. Optionally or additionally, the term “control computer” refers to a device that is capable of executing a provided or included program, preferably with standardized programming language (for example C++, JavaScript or Python), and/or of controlling and/or accessing data storage devices and/or other devices such as input interfaces and output interfaces. The term control computer also refers to a multiplicity of processors or a multiplicity of (sub)computers that are interconnected and/or connected and/or otherwise communicatively connected and possibly share one or more other resources, such as for example a memory.

[0028] A voltage between the conductors of the charging cable 5 preferably is monitored by the insulation monitor 3. If a voltage is applied here, this means that the contactor 4 is in the closed switching state and the correct connection of the insulation monitor 3 can be checked.

[0029] The charging cable 5 is connected to first connections 3.1 of the insulation monitor 3 or the insulation monitor 3 is connected at the first connections 3.1 to the charging cable 5. Electrical conductors and/or busbars between the contactor 4 and the power electronics system 7 are connected to second connections 3.2. The insulation monitor 3 monitors the electrical insulation of the electrical conductors and/or busbars between the contactor 4 and the power electronics system 7 via the second connections 3.2. Furthermore, the insulation monitor 3 checks the correct connection of the second connections 3.2 at the electrical conductors and/or busbars between the contactor 4 and the power electronics system 7. Both can be carried out in the closed and open switching state.

[0030] To ensure the correct performance of the charging process, the insulation monitor 3 compares the measurement values ascertained at the first connections 3.1 with the measurement values ascertained at the second connections 3.2 during the charging process. Discrepancies that imply possible problems and faults can thus be discovered and the charging process can be terminated in case of emergency.

LIST OF REFERENCE DESIGNATIONS

[0031] 1 Charging device [0032] 2 Vehicle [0033] 3 Insulation monitor [0034] 3.1 First connections [0035] 3.2 Second connections [0036] 4 Contactor [0037] 5 Charging cable [0038] 6 Signal line [0039] 7 Power electronics system