Circuit arrangement for diagnosing a service disconnect line of an electrically operated vehicle

Abstract

The invention describes a circuit arrangement for diagnosing a service disconnect line (4) of an electrically operated vehicle, which comprises two electrical systems with different high voltages. The service disconnect line (4) is wired between a first terminal (6) and a second terminal (2) and comprises at least one manual isolating element (3), wherein in the operation of the circuit arrangement in the vehicle, the voltage applied at the second terminal (2) is detected with a measuring device (5) and voltage information (s4) representing the voltage is evaluated by a computing unit (30). The computing unit (30) is configured to separate or not separate the electrical system with the high voltage from consumers connected to the electrical system depending on the voltage information. The computing unit (30) is furthermore configured to determine a fault of the service disconnect line (4) for the purpose of executing a test routine by operating respective switching elements (13, 21, 22) to apply different voltage or current levels at the first terminal (6) and / or the second terminal (2) in an iterative manner, detecting the respective voltage applied at the second terminal (2) with the measuring device (5) and evaluating voltage information (s4) representing the voltage by the computing unit (30).

Description

Technical Field

[0001] This invention relates to a circuit device for diagnosing a service disconnect circuit in an electrically operated vehicle, the vehicle comprising two electrical systems with different high voltages, wherein the service disconnect circuit includes at least one manually operated isolation element and an optional fuse, and is wired between a first terminal and a second terminal. During operation of the circuit device in the vehicle, a measuring device detects the voltage applied to the second terminal and a calculation unit evaluates voltage information representing that voltage. The calculation unit is configured to disconnect or not disconnect the electrical system with the high voltage from the power consumption devices connected to said electrical system based on the voltage information. Background Technology

[0002] Electric vehicles possess two electrical systems with different voltage levels. The lower voltage system, typically 12V, 24V, or 48V, supplies power to low-power appliances such as control equipment, lights, comfort and ventilation systems, navigation systems, and driver assistance systems. The higher voltage system, also known as the high-voltage system, supplies power to high-power appliances such as the electric drive unit of an electric vehicle. Here, the voltage in the high-voltage system can be 400V or higher, depending on the design of the high-voltage system.

[0003] In this application, "electric vehicle" is understood to refer to either a battery electric vehicle (BEV) or a hybrid electric vehicle (HEV or Plug-in Hybrid Electric Vehicle, PHEV), where the battery electric vehicle has only an electric motor as its drive source, and the hybrid electric vehicle has a combination of an internal combustion engine and an electric motor as its drive source. Electric vehicles can be understood not only as motor vehicles, but also as all electric vehicles, such as ground transport vehicles or forklifts.

[0004] The presence of two electrical systems with different high voltages presents safety challenges in both accident and service work situations. Every operation and manipulation at the high-voltage components of an electric vehicle can be fatal in some circumstances. Workshop personnel performing maintenance or repair work, or first responders or firefighters in the event of an accident, are not permitted to come into contact with the high voltage of the high-voltage electrical system. Therefore, manually isolating elements, also known as manual service disconnect switches, are installed in so-called service disconnect circuits to quickly and safely cut off the voltage.

[0005] The manually disconnecting element is located in the service disconnect line, where disconnecting the manually disconnecting element creates a safe condition for workshop personnel or rescue teams. For this purpose, during the operation of the circuit, for example, a measuring device detects the voltage applied to the terminals, which changes depending on whether the manually disconnecting element is open or closed. In this case, a calculation unit evaluates voltage information representing the voltage, wherein the calculation unit activates the high-voltage electrical system whenever (e.g., due to intentional disconnection by a rescue team) causes an open-circuit state in the manually disconnecting element or service disconnect line.

[0006] The drawback of the solutions currently in use is that the identification of fault conditions at the terminals where the voltage is being evaluated is incomplete for various fault scenarios. Summary of the Invention

[0007] The objective of this invention is to describe a functionally improved circuit arrangement for diagnosing service disconnection lines in electric vehicles comprising two electrical systems with different voltage levels.

[0008] This task is accomplished by a circuit device used for diagnosing service disconnection lines on electrically operated vehicles. Advantageous designs are derived from other embodiments.

[0009] A circuit arrangement is proposed for diagnosing a service disconnect line in an electrically operated vehicle, the vehicle comprising two electrical systems with different high voltages. The service disconnect line is connected between a first terminal and a second terminal and includes at least one manually operated isolating element. Optionally, a fuse may be provided in the service disconnect line. During operation of the circuit arrangement in the vehicle, a measuring device detects the voltage applied to the second terminal, and a calculation unit evaluates voltage information representing that voltage. The calculation unit is configured to disconnect or not disconnect the electrical system with the higher voltage from the power consumption devices connected to said electrical system based on the voltage information.

[0010] According to the present invention, the calculation unit is further configured to perform test routines to determine the fault of the service disconnect line by iteratively applying different voltage or current levels by manipulating the respective switching elements at the first and / or second terminals, detecting the respective voltage applied to the second terminal using a measuring device, and evaluating voltage information representing the voltage by the calculation unit in order to perform test routines.

[0011] In particular, the computing unit is configured to detect short circuits between the service disconnect line and the potential of an electrical system with low voltage, or with a reference potential. Furthermore, the computing unit is configured to detect interruptions in the service disconnect line that are not caused by operating a manual isolation element or by a rescue team selectively disconnecting the service disconnect line.

[0012] Therefore, the circuit device according to the invention results in improved safety for workshop personnel or rescue teams, because in the absence of monitoring, a short circuit between the second terminal and the potential of the electrical system with low voltage may still prevent the establishment of a safe state despite the intentional disconnection of the manual isolation element. Furthermore, in the absence of monitoring by means of the circuit device, a short circuit between the second terminal and the reference potential may prevent the establishment of the vehicle's driving equipment state.

[0013] The present invention is based on the consideration that it is impossible to identify a fault condition at the second terminal, which is terminal 30c (Kl30c) of the vehicle, simply by evaluating the voltage level present in an electrical system with low voltage. Instead, identifying a short circuit or interruption at the second terminal requires an active, externally applied voltage and / or current level at the second terminal. Change.

[0014] The proposed circuitry thus addresses this issue by configuring the computing unit to iteratively manipulate the respective switching elements at the first and / or second terminals to apply different voltage or current levels in order to execute test routines. The voltage applied at the second terminal can then be detected using a measuring device. Here, by evaluating voltage information (one or more) representing the voltage, the computing unit can thus deduce a fault or a targeted disconnection of a service line caused, for example, by disconnecting a manually isolating element or by mechanical disassembly by a rescue team.

[0015] According to a suitable design of a first variant in which a switchable power supply device is incorporated, a first controllable switching element is connected between the supply voltage and the node of a voltage divider consisting of two resistors. The supply voltage can be derived, for example, from an electrical system with low voltage and may include, for example, 12V, 24V, or 48V. The series circuit of the voltage divider consisting of two resistors is connected between the first terminal and a reference potential.

[0016] According to a suitable design, the computing unit is configured to successively control the first switching element from a conducting state to a non-conducting state, and if a potential of an electrical system with low voltage is detected at the second terminal in either of the two switching positions of the first switching element, it is inferred that the service disconnect line is short-circuited to the potential of the electrical system with low voltage.

[0017] In another advantageous configuration, the second controllable switching element is connected to the second terminal via a resistor. The computing unit is suitably configured to successively control the second switching element from an on state to a non-conducting state, or vice versa, and to infer that the service disconnect line is short-circuited with the reference potential if a reference potential is detected at the second terminal in either of the two switching positions of the second switching element.

[0018] In another variation using a current source and current sink, current is applied to the first terminal via a fixed or variable first current source. The computing unit is suitably configured to infer that the service disconnect line is short-circuited to the potential of the low-voltage electrical system if a potential of the low-voltage electrical system is detected at the second terminal.

[0019] According to another suitable design, the computing unit is configured to infer that the service disconnect line is short-circuited to the reference potential of the electrical system if a reference potential of the electrical system is detected at the second terminal.

[0020] According to another design of this variant, the second terminal is connected to a switchable current source device via a resistor, the switchable current source device applying current to the second terminal or externally applying current to the second terminal.

[0021] As described above, the second terminal is the vehicle's terminal 30c (abbreviated as Kl30c). In contrast, the first terminal is a test cycle-specific terminal, which is specifically different from the vehicle's terminal 30 (Kl30).

[0022] According to another suitable design, the computing unit is configured to execute the test routine once for each driving cycle or each charging cycle of the vehicle. Alternatively or additionally, the computing unit is configured to execute the test routine periodically during the operation of the vehicle.

[0023] The proposed circuitry can prevent erroneous assessment of the voltage signal applied to the second terminal, thereby especially avoiding or eliminating dangerous and undesirable vehicle conditions. Attached Figure Description

[0024] The invention will now be described in more detail with reference to the embodiments shown in the accompanying drawings. Wherein:

[0025] Figure 1 shows a known circuit arrangement, in which the conventional wiring of the service disconnect signal loop is shown;

[0026] Figure 2 A first embodiment of the circuit device according to the invention, having a switchable power supply, is shown; and

[0027] Figure 3 A second embodiment of the circuit device according to the invention, having a current source and a current sink, is shown. Detailed Implementation

[0028] The same components are equipped with the same reference numerals in the figure.

[0029] Figure 1 shows a known circuit arrangement of a service disconnect signal circuit commonly used in electrically operated vehicles, which is used to induce a safety status for workshop personnel or rescue teams.

[0030] The signal loop is formed by service disconnect line 4 (hereinafter: line 4), in which a manual isolation element 3 is arranged, for example, as a disconnect switch. Line 4 is wired between terminal 1 and vehicle terminal 30 (Kl30), and between terminal 2 and vehicle terminal 30c (Kl30c). Terminal 1 is connected to an electrical system with a low voltage (e.g., 12V). If the electrical system with the low voltage has a voltage different from 12V, such as 24V, then terminal 1 is connected to 24V. A measuring device 5 is connected to terminal 2. The voltage applied at terminal 2 (Kl30c) is detected by the measuring device 5. Voltage information s4, representing the voltage, is transmitted to a calculation unit 30, such as a control device, and evaluated by the calculation unit.

[0031] If voltage information s4 corresponds to the voltage of an electrical system (not shown in detail) with a low voltage (here: 12V), then line 4 connects terminals 1 and 2 to each other. The high-voltage battery (not shown in the figure), i.e., the part of the high-voltage electrical system (hereinafter: high-voltage electrical system) also not shown, can then be connected to the cable bundle and / or the power consumers of the high-voltage electrical system. Conversely, if line 4 is disconnected by means of the manual isolating element 3, the voltage information s4 determined by the measuring device 5 corresponds to the reference potential GND (where it is assumed here that the high-voltage electrical system and the low-voltage electrical system have the same reference potential GND). The calculation unit 30 then operates the corresponding switching element to disconnect the high-voltage battery from the cable bundle and / or the power consumers of the high-voltage electrical system.

[0032] Instead of the manual isolation element 3 operated by workshop personnel, the line 4 can also be disconnected by mechanical means (especially violently), such as by a rescue team cutting it with rescue shears.

[0033] A short circuit at terminal 2 (Kl30c) to a line in an electrical system with low voltage (i.e., 12V) may prevent the establishment of a safe state after the manual isolating element 3 has been selectively disconnected or the line 4 has been mechanically disconnected. A short circuit at terminal 2 (Kl30c) to the reference potential GND may also prevent the establishment of a driving-ready state.

[0034] Figure 2 and 3 The embodiment shown enables the identification of fault conditions at terminal 2 (Kl30c) by actively applying a change in the voltage and / or current level at terminal 2 (Kl30c). Terminal 2 (Kl30c) corresponds to the second terminal in this specification.

[0035] Figure 2 An embodiment is shown that actively changes the voltage level at the second terminal 2 (Kl30c). Unlike the device according to FIG1 known from the prior art, line 4 is now wired between the second terminal 2 (Kl30c) and the first terminal 6, which is a test cycle-specific terminal and, in particular, different from the vehicle's terminal 1 (Kl30). The manual isolation element 3 is again wired in line 4. Terminal 1 (Kl30) is inactive for this circuit device and... Figure 2 The diagram is shown for informational purposes only, to illustrate that the first terminal 6 is a different terminal from terminal 1 (Kl30).

[0036] The first controllable switching element is wired between node 15 of a voltage divider consisting of two resistors and diode 14, which is connected to the supply voltage, for example, 12V. The supply voltage may, for example, be the electrical system voltage of an electrical system with a low voltage. In principle, the supply voltage may also be a different voltage. The controllable switching element 13 is switched on or off by means of a control signal s1 from the already described computing unit 30. The series circuit of the voltage dividers 11 and 12 consisting of two resistors is wired between the first terminal 6 and the reference potential GND.

[0037] An optional second controllable switch element 21 is connected to the second terminal 2 (Kl30c) via resistor 23. The other end of the second controllable switch element 21 is connected to the supply voltage (here: 12V). Similarly, another optional third controllable switch element 22 is shown, connected between node 24 and the reference potential GND, node 24 being formed between the second controllable switch element 21 and resistor 23. The second controllable switch element 21 is switched on or off via a second control signal s2 by the calculation unit 30. The third controllable switch element 22 is switched on or off by a third control signal s3 by the calculation unit 30.

[0038] For simplified functionality of the circuit device, the circuit device connected to the second terminal 2 (Kl30c) may be completely or partially unnecessary.

[0039] The calculation unit 30 is configured to successively control the first switching element 13 from a conducting state to a non-conducting state. If a potential of a low-voltage electrical system is detected at the second terminal 2 (Kl30c) in either of the two successive switching positions of the first switching element 13, a short circuit in line 4 is deduced by the calculation unit 30. The presence of the second and third controllable switching elements 21 and 22 is not necessary for performing this test. However, if these two controllable switching elements are present, they are switched to the off state.

[0040] The following table again shows different variations of the switching position of the first switching element and the voltage information s4 obtained at the second terminal 2 (Kl30c):

[0041]

[0042] Table 1: Fault Status Matrix

[0043] To deduce that line 4 is short-circuited with the reference potential GND, the calculation unit 30 is configured to successively control the second switching element 21 from an on state to a non-conducting state. The switching sequence can also be reversed. During the operation of the second controllable switching element 21, the first and third controllable switching elements 13 and 22 are switched to off. If the reference potential is detected at the second terminal 2 (Kl30c) in either of the two switching positions of the second switching element 21, it can be deduced that line 4 is short-circuited with the reference potential.

[0044] Figure 3 A second embodiment is shown, in which a current source and a current sink are used instead of a switchable power supply device. A first terminal 6 is connected to a first current source 16, which is supplied with a power supply potential of 12V (either the power supply voltage of the electrical system or a different power supply voltage). A switching device including first and second controllable switching elements 21, 22 is connected to a second terminal 2 (Kl30c). In this case, the first controllable switching element 21 is wired between node 24 and current source 25. Current source 25 is connected to the power supply potential of 12V. The second controllable switching element 22 is wired between node 24 and current source 26, which is connected to a reference potential.

[0045] The calculation unit 30 is configured to infer that line 4 is short-circuited to the potential of the electrical system with low voltage if a potential of the electrical system with low voltage is detected at the second terminal 2 (Kl30c). This test is performed by switching the second and third controllable switching elements 21 and 22 to the off position.

[0046] If the reference potential GND of the electrical system is activated at the second terminal 2, it can be deduced that line 4 is short-circuited to the reference potential GND of the electrical system with low voltage. This test is performed by switching the second controllable switching element 21 to conduct and the third controllable switching element 22 to cut off.

[0047] If the second and third controllable switching elements s2 and s3 are switched on, the switchable current source device functions as a voltage divider, thus requiring an intermediate voltage at the second terminal 6 (Kl30c), i.e., a voltage between the reference potential and the supply voltage (here: 12V). If a different voltage is present at terminal 6 (Kl30c), a short circuit with a low-voltage electrical system can be deduced.

[0048] List of reference numerals

[0049] 1. Third terminal (Kl30)

[0050] 2. Second terminal (Kl30c)

[0051] 3 Manual Interruption Components

[0052] 4. Service disconnected.

[0053] 5. Measuring device

[0054] 6. First terminal (Kl30)

[0055] 11 Resistors

[0056] 12 resistors

[0057] 13 Controllable switching elements

[0058] 14 Diodes

[0059] 15 nodes

[0060] 16 Current Sources

[0061] 21 Controllable switching elements

[0062] 22 Controllable switching elements

[0063] 23 Resistors

[0064] 24 nodes

[0065] 25 Current Source

[0066] 26 Current Source

[0067] 30 computing units

[0068] s1 is the control signal for the controllable switching element 13.

[0069] s2 is the control signal for the controllable switching element 21.

[0070] S3 is the control signal for the controllable switching element 22.

[0071] S4 voltage information

[0072] GND reference potential

[0073] 12V power supply potential.

Claims

1. A circuit device for diagnosing a service disconnect line (4) of an electrically operated vehicle, the electrically operated vehicle comprising a high-voltage electrical system and a low-voltage electrical system, wherein the service disconnect line (4) is wired between a first terminal (6) and a second terminal (2) and includes at least one manually operated isolation element (3), wherein during operation of the circuit device in the vehicle, a measuring device (5) detects the voltage applied to the second terminal (2), and a calculation unit (30) evaluates voltage information (s4) representing the voltage, wherein the calculation unit (30) is configured to connect the electrical system with the high voltage to the service disconnect line (4) based on the voltage information. The power consumption connected to the high-voltage electrical system is disconnected or not disconnected, wherein in order to perform a test routine to determine the fault of the service disconnect line (4), the calculation unit (30) is further configured to apply different voltage or current levels at the first terminal (6) and / or the second terminal (2) in an iterative manner by manipulating the respective switching elements, detect the respective voltage applied to the second terminal (2) using the measuring device (5), and evaluate the voltage information (s4) representing the voltage by the calculation unit (30), so that the calculation unit can infer the fault of the service disconnect line or disconnect it in a targeted manner.

2. The circuit device according to claim 1, wherein the computing unit (30) is configured to detect a short circuit between the service disconnect line (4) and the potential of the electrical system with low voltage or with the reference potential (GND) as a fault detection.

3. The circuit arrangement according to claim 1 or 2, wherein the computing unit (30) is configured to detect interruptions in the service disconnect line (4) as a fault.

4. The circuit arrangement according to claim 1 or 2, wherein the first controllable switching element (13) is connected between the supply voltage (12V) and the node (15) of the voltage divider (11, 12) consisting of two resistors, wherein the series circuit of the voltage divider (11, 12) consisting of two resistors is connected between the first terminal (6) and the reference potential (GND).

5. The circuit device according to claim 4, wherein the computing unit (30) is configured to successively control the first controllable switching element (13) from an on state to a non-on state, and if a potential of an electrical system with low voltage is detected at the second terminal (2) in either of the two switching positions of the first controllable switching element (13), it is deduced that the service disconnect line (4) is short-circuited to the potential of the electrical system with low voltage.

6. The circuit arrangement according to claim 4, wherein the second controllable switching element (21) is connected to the second terminal (2) via a resistor (23).

7. The circuit arrangement according to claim 5, wherein the second controllable switching element (21) is connected to the second terminal (2) via a resistor (23).

8. The circuit apparatus according to claim 6, wherein the computing unit (30) is configured to successively control the second controllable switching element (21) from an on state to a non-on state, or vice versa, and if the reference potential (GND) is detected at the second terminal (2) in either of the two switching positions of the second controllable switching element (21), it is inferred that the service disconnect line (4) is short-circuited with the reference potential (GND).

9. The circuit arrangement according to claim 1 or 2, wherein current is applied to the first terminal (6) by a fixed or variable first current source (16).

10. The circuit arrangement according to claim 9, wherein the computing unit (30) is configured to infer that the service disconnect line (4) is short-circuited to the potential of the electrical system with low voltage if a potential of the electrical system with low voltage is detected at the second terminal (2).

11. The circuit arrangement of claim 9, wherein the computing unit (30) is configured to infer that the service disconnect line (4) is short-circuited to the reference potential of the electrical system if the reference potential (GND) of the electrical system is detected at the second terminal (2).

12. The circuit arrangement of claim 10, wherein the computing unit (30) is configured to infer that the service disconnect line (4) is short-circuited to the reference potential of the electrical system if the reference potential (GND) of the electrical system is detected at the second terminal (2).

13. The circuit device according to claim 9, wherein the second terminal (2) is connected to a switchable current source device via a resistor (23), the switchable current source device applying current to the second terminal (2) or externally applying current to the second terminal.

14. The circuit device according to claim 1 or 2, wherein the second terminal (2) is terminal 30c of the vehicle.

15. The circuit device according to claim 1 or 2, wherein the first terminal (6) is a test cycle specific terminal, the test cycle specific terminal being different from the terminal 30 of the vehicle.

16. The circuit arrangement according to claim 1 or 2, wherein the computing unit (30) is configured to perform the test routine once for each driving cycle or charging cycle of the vehicle.

17. The circuit arrangement according to claim 1 or 2, wherein the computing unit (30) is configured to periodically execute the test routine during operation of the vehicle.

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