systems, motor vehicles

Abstract

A system (2) comprises a controller (3) with a housing (4), in which at least one computing unit (5, 6) of the controller (3) is arranged, an electrical ground connection (13) arranged outside the housing (4), a first ground line (19) via which the controller (3) is electrically connected to the ground connection (13), a second ground line (20) via which the controller (3) is electrically connected to the ground connection (13), and a sensor device (21) configured to monitor a first ground current flowing through the first ground line (19) and a second ground current flowing through the second ground line (20). The sensor device (21) for monitoring the first ground current and the second ground current comprises an XMR sensor (22).

Description

Technical Field

[0001] The invention relates to a system comprising a controller having a housing in which at least one computing unit of the controller is arranged, an electrical ground connection arranged outside the housing, a first ground line via which the controller is electrically connected to the ground connection, a second ground line via which the controller is electrically connected to the ground connection, and a sensor device designed to monitor a first ground current flowing through the first ground line and a second ground current flowing through the second ground line.

[0002] The invention further relates to a motor vehicle having such a system. Background Art

[0003] A controller is installed, for example, in a motor vehicle to execute one or more control processes for controlling the motor vehicle. To this end, the controller typically has at least one computing unit disposed within the controller housing. To conduct current, the controller is typically electrically connected to an electrical ground connection disposed outside the housing.

[0004] For example, the publication WO 2017 008 057 A1 discloses a controller electrically connected to a ground connection via two redundant ground lines. There is a first ground line, via which the controller is electrically connected to the ground connection, and a second ground line, via which the controller is electrically connected to the ground connection. This allows for particularly reliable current conduction. To monitor the ground lines, a sensor device is assigned to each ground line. The sensor device is configured to monitor a first ground current flowing through the first ground line and a second ground current flowing through the second ground line. The controller, ground connection, ground lines, and sensor device together form a system of the type mentioned above. By monitoring the ground currents, it is possible to determine, for example, whether a fault in the ground lines, such as a ground fault in one of the ground lines, has occurred.

[0005] The sensor device known from the publication WO 2017 008 057 A1 has a plurality of shunt components and a plurality of comparators for monitoring the ground current. Summary of the Invention

[0006] The system according to the invention with the features of claim 1 has the advantage that the controller can be designed to save space. According to the invention, for this purpose, the sensor device for monitoring the first and second ground currents includes an XMR sensor. An XMR sensor is provided that is designed to monitor the first and second ground currents. The sensor device is thus designed to be compact and space-saving. In particular, a comparator, which typically takes up a large amount of space, is not required for the sensor device. The sensor device is preferably designed without a comparator. An XMR sensor can be understood as a sensor that has at least one magnetoresistive resistor element as a sensor element (a magnetoresistive resistor element is a resistor element whose resistance is influenced by a magnetic field in the region of the resistor element). The XMR sensor preferably includes a plurality of such magnetoresistive resistor elements. A change in the first ground current causes a change in a first magnetic field surrounding the first ground line. A change in the second ground current correspondingly causes a change in a second magnetic field surrounding the second ground line. To monitor the ground current, the XMR sensor is arranged adjacent to the ground line such that changes in the first magnetic field and / or the second magnetic field influence the resistance of the magnetoresistive resistor element. The resistance is indirectly influenced by changes in the ground current. The XMR sensor monitors the ground current using the magnetoresistive effect, for example, the anisotropy magnetoresistive effect (AMR), the giant magnetoresistive effect (GMR), the colossal magnetoresistive effect (CMR), the tunneling magnetoresistive effect (TMR), or the planar Hall effect. The ground line is preferably electrically connected to a star point of the controller. The grounding lines are thus connected in parallel to the star point and to a ground connection located outside the housing. In this regard, the grounding lines are generally connected in parallel to each other to redundantly connect the controller to the ground connection. Because the ground connection is located outside the housing, the grounding lines also extend at least partially outside the housing. The resistance value of the first grounding line preferably at least substantially corresponds to the resistance value of the second grounding line, so that the grounding current has the same current value, at least in the absence of a grounding line fault.Regarding the flow direction of the ground current, it is assumed that the ground current flows from the controller to the ground terminal.

[0007] According to a preferred embodiment, the XMR sensor includes a measuring bridge with a first magnetoresistive resistor element, a second magnetoresistive resistor element, a third magnetoresistive resistor element, and a fourth magnetoresistive resistor element. This ensures that a homogeneous stray magnetic field (i.e., a magnetic field that is not affected by variations in the ground current) does not hinder monitoring of the ground current. This allows for particularly precise monitoring of the ground current. The measuring bridge is preferably designed as a Wheatstone bridge. The resistor elements are preferably each designed as a spin-valve type resistor element. To this end, each resistor element preferably has at least one section made of a soft magnetic material and at least one section made of a hard magnetic material.

[0008] The resistance elements are preferably designed identically. In the absence of a magnetic field acting on the resistance elements, the resistance elements have the same resistance. This simplifies the software evaluation of the measurement data detected by the XMR sensor.

[0009] According to a preferred embodiment, the measuring bridge includes a first conductor and a second conductor, wherein the conductors are electrically connected in parallel to an input of the measuring bridge and to an output of the measuring bridge, wherein the first conductor has the first resistor element adjacent to the input and the third resistor element adjacent to the output, and wherein the second conductor has the second resistor element adjacent to the input and the fourth resistor element adjacent to the output. The input can be understood as the portion of the measuring bridge via which the measuring bridge is electrically connected to a power supply line. The output can be understood as the portion of the measuring bridge via which the measuring bridge is electrically connected to ground. The potential difference between the input and the output is referred to as the supply voltage.

[0010] The system preferably includes an evaluation unit configured to detect the bridge voltage of the measuring bridge and, based on the bridge voltage, determine whether the first and / or second ground lines have a ground interruption. If a ground interruption occurs in one of the ground lines, the controller and the ground connection are no longer electrically connected via the ground line in question, preventing ground current from flowing through the ground line. The controller is then no longer redundantly connected to the ground connection. In this state, current flow is limited, and the controller should not be used to execute control processes. Determining whether a ground interruption exists is therefore particularly important for reliable execution of control processes. The potential difference between a first portion of the first conductor, located between the first and third resistor elements, and a second portion of the second conductor, located between the second and fourth resistor elements, is referred to herein as the bridge voltage. The first portion is preferably connected to a first analog-to-digital converter of the evaluation unit via a first signal line. The second portion is preferably connected to a second analog-to-digital converter of the evaluation unit via a second signal line.

[0011] According to a preferred embodiment, the first and fourth resistors are arranged adjacent to the first ground line such that the resistance values ​​of the first and fourth resistors are affected by changes in the first ground current, and the second and third resistors are arranged adjacent to the second ground line such that the resistance values ​​of the second and third resistors are affected by changes in the second ground current. The first and fourth resistors are assigned to the first ground line. The second and third resistors are assigned to the second ground line. Preferably, the resistance values ​​of the first and fourth resistors are affected only by changes in the first ground current and not by changes in the second ground current. Preferably, the resistance values ​​of the second and third resistors are affected only by changes in the second ground current and not by changes in the first ground current.

[0012] According to a preferred embodiment, the first and fourth resistor elements are designed such that a change in the first ground current affects the resistance of the first and fourth resistor elements to the same extent, and the second and third resistor elements are designed such that a change in the second ground current affects the resistance of the second and third resistor elements to the same extent. Taking the first and fourth resistor elements as an example, this means that both resistor elements are designed either such that an increase in the first ground current causes an increase in their resistance or such that an increase in the first ground current causes a decrease in their resistance. This is preferably achieved by appropriately positioning the soft-magnetic and hard-magnetic positions of the resistor elements. This design of the sensor unit makes it particularly easy to determine whether there is a ground interruption in one of the ground lines. If there is no ground interruption, the voltage value of the bridge voltage corresponds at least substantially to an expected nominal voltage value. However, if the voltage value of the bridge voltage deviates from the nominal voltage value by more than a predetermined voltage threshold, the evaluation unit determines that there is a ground interruption in one of the ground lines. Depending on whether the voltage value of the bridge voltage does not exceed or exceeds the nominal voltage value, the evaluation unit determines which of the ground lines is affected by the ground interruption.

[0013] The XMR sensor is preferably integrated into the controller and arranged within a housing of the controller, thereby protecting the XMR sensor from damage.

[0014] According to a preferred embodiment, it is provided that the XMR sensor is designed without a magnetic flux concentrator. The installation space required for the sensor device is thereby further reduced.

[0015] The XMR sensor is preferably configured as a GMR sensor or a TMR sensor. This configuration of the XMR sensor clearly displays the change in the resistance value of the resistor element. Therefore, an amplifier between the conductor and the analog-to-digital converter is unnecessary. Alternatively, the XMR sensor can preferably be configured as an AMR sensor, a CMR sensor, or an EMR sensor.

[0016] The motor vehicle according to the invention is characterized by the system according to the invention using the features of claim 11. This also results in the advantages already mentioned. Further preferred features and combinations of features can be derived from the preceding description and from the claims. The controller is particularly preferably designed to fully automatically control the parking process of the motor vehicle as a controlled process. The ground connection is preferably a ground connection for the body of the motor vehicle or a ground connection for the battery of an electrical energy storage device of the motor vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described below with reference to the accompanying drawings, wherein:

[0018] Figure 1 A motor vehicle is shown with a system; and

[0019] Figure 2 A detailed view of the sensor arrangement of the system is shown. DETAILED DESCRIPTION

[0020] Figure 1 A simplified diagram shows a motor vehicle 1 with a system 2. The system 2 has a control unit 3. The control unit 3 has a housing 4 in which a plurality of computing units 5, 6 are arranged. The computing units 5 and 6 each have at least one circuit.

[0021] The computing unit 5 is the main computing unit of the controller 3. It is designed to fully automatically execute a parking process for the motor vehicle 1 as a controlled process. To this end, the computing unit 5 is signal-connected to the surroundings sensor system of the motor vehicle 1, the steering system of the motor vehicle 1, the drive system of the motor vehicle 1, and the brake system of the motor vehicle 1, and is designed to control the steering system, the drive system, and the brake system based on the surroundings data detected by the surroundings sensor system.

[0022] The system 2 includes an electrical energy storage device 7. The energy storage device 7 is arranged outside the housing 4. The positive pole 8 of the energy storage device 7 is electrically connected to a power supply contact 10 of the controller 3 via a line 9. To supply electrical energy to the computing units 5 and 6, the computing units 5 and 6 are electrically connected to the power supply contact 10 via a line 11 or a line 12.

[0023] The computing units 5 and 6 are also electrically connected to a ground point 14 or 15 of the controller 3 , respectively. The ground points 15 and 14 are electrically connected to a star point 16 of the controller 3 . The star point 16 is arranged within the housing 6 of the controller 3 .

[0024] System 2 also has a ground connection 13 as part of the body ground of motor vehicle 1. Ground connection 13 can be disconnected from control unit 3 and arranged outside housing 4. Ground connection 13 is electrically connected to battery ground 18 of energy storage device 7 via a line 17. To draw current from computing units 5 and 6, computing units 5 and 6 are electrically connected to ground connection 13 via battery ground 18. System 2 also has a first ground line 19 and a second ground line 20.

[0025] First ground line 19 is electrically connected to star point 16 on the one hand and to battery ground 18 on the other hand. Second ground line 20 is also electrically connected to star point 16 on the one hand and to battery ground 18 on the other hand. Ground lines 19 and 20 extend partially outside housing 4 . Ground lines 19 and 20 are connected in parallel to star point 16 and to battery ground 18, so that overall, ground lines 19 and 20 are connected in parallel to each other. Computer units 5 and 6 of controller 3 are thus redundantly connected to ground connection 13 via ground lines 19 and 20.

[0026] System 2 also includes a sensor device 21 arranged in housing 4 and integrated into controller 3 . Sensor device 21 is designed to monitor a first ground current flowing through first ground line 19 and a second ground current flowing through second ground line 20 . It is determined that during normal operation of controller 3 , the ground current flows from star point 16 to ground connection 13 . To monitor the ground current, sensor device 21 includes an XMR sensor 22 . In this case, XMR sensor 22 is a GMR sensor 22 . Alternatively, XMR sensor 22 may be a TMR sensor, a CMR sensor, an EMR sensor, or an AMR sensor.

[0027] The XMR sensor 22 is electrically connected to the supply contact 10 and, therefore, to the positive pole 8 of the energy storage device 7 via a supply line 23. Furthermore, the XMR sensor 22 is electrically connected to a further ground point 25 of the control device 3 via a line 24. The further ground point 25 is also electrically connected to the star point 16. Furthermore, the XMR sensor 22 is connected to a first analog-to-digital converter 27 of the computing unit 6 via a first signal line 26 and to a second analog-to-digital converter 29 of the computing unit 6 via a second signal line 28.

[0028] Next reference Figure 2 Further explain the technical solution of the sensor device 21. Figure 2 As can be seen in FIG, the XMR sensor 22 has a measuring bridge 30. The measuring bridge 30 has an inlet 31 and an outlet 32. The inlet 31 is electrically connected to the supply contact 10 by means of the supply line 23. The outlet 32 ​​is electrically connected to a further ground point 25 by means of the line 24. The potential difference between the inlet 31 and the outlet 32 ​​is referred to as the supply voltage.

[0029] The measuring bridge 30 further comprises a first conductor 33 and a second conductor 34. The first conductor 33 and the second conductor 34 are electrically connected in parallel to the inlet 31. The first conductor 33 and the second conductor 34 are also electrically connected in parallel to the outlet 32.

[0030] The first conductor 33 has a first magnetoresistive resistor element 35 adjacent to the inlet 31. The second conductor 34 has a second magnetoresistive resistor element 36 adjacent to the inlet 31. The first conductor 33 has a third magnetoresistive resistor element 37 adjacent to the outlet 32. The second conductor 34 has a fourth magnetoresistive resistor element 38 adjacent to the outlet 32. Since the XMR sensor 22 is configured as a GMR sensor 22, the resistor elements 35, 36, 37, and 38 are configured as GMR elements 35, 36, 37, and 38.

[0031] In the present case, the resistor elements 35 , 36 , 37 and 38 are each designed as a spin-valve type resistor element or GMR element. In this respect, the resistor elements 35 , 36 , 37 and 38 each have at least one soft-magnetic site and at least one hard-magnetic site.

[0032] If the XMR sensor 22 is designed as a TMR sensor, AMR sensor, CMR sensor or EMR sensor, the resistor elements 35 , 36 , 37 and 38 are preferably each designed as a spin-valve TMR element, AMR element, CMR element or EMR element.

[0033] The first conductor 33 has a first portion 39 located between the first resistor element 35 and the third resistor element 37. The second conductor 34 has a second portion 40 located between the second resistor element 36 and the fourth resistor element 38. The potential difference between the first portion 39 and the second portion 40 is called the bridge voltage. The first portion 39 has a first terminal 41, to which the first signal line 26 is connected. The second portion 40 has a second terminal 42, to which the second signal line 28 is connected. The computing unit 6 is thus supplied with the potential of the first portion 39 and the potential of the second portion 40 via the signal lines 26 and 28, and thus with the bridge voltage.

[0034] The change of the first ground current flowing through the first ground wire 19 will cause a change of a first magnetic field around the first ground wire, and the change of the second ground current flowing through the second ground wire will correspondingly cause a change of a second magnetic field around the second ground wire.

[0035] The first resistor element 35 and the fourth resistor element 38 are arranged adjacent to the first ground line 19 such that a change in the first magnetic field causes a change in the resistance of the first resistor element 35 and a change in the resistance of the fourth resistor element 38. The first resistor element 35 and the fourth resistor element 38 are assigned to the first ground line 19. In the present embodiment, the resistor elements 35 and 38 are designed such that an increase in the first ground current causes a decrease in the resistance of the resistor elements 35 and 38.

[0036] Second resistor element 36 and third resistor element 37 are arranged adjacent to second ground line 20 such that a change in the second magnetic field causes a change in the resistance of second resistor element 36 and a change in the resistance of third resistor element 37. Second resistor element 36 and third resistor element 37 are assigned to second ground line 20. In the present embodiment, resistor elements 36 and 37 are designed such that an increase in the second ground current causes a decrease in the resistance of resistor elements 36 and 37.

[0037] The calculation unit 6 is designed as an evaluation unit 6 for determining, based on the bridge voltage, whether one of the ground lines 19 or 20 has a ground interruption. If one of the ground lines 19 or 20 has a ground interruption, the star point 16 is no longer electrically connected to the ground connection 13 via the ground line 19 or 20 in question, so that a ground current cannot flow through the ground line 19 or 20.

[0038] If there is no ground interruption, the voltage value of the bridge voltage corresponds at least substantially to an expected normal voltage value, which typically corresponds to 0 V. If the voltage value of the bridge voltage corresponds at least substantially to the normal voltage value, the calculation unit 6 accordingly determines that there is no ground interruption.

[0039] If there is a ground interruption in first ground line 19, the resistance values ​​of resistor elements 36 and 37 are smaller than the resistance values ​​of resistor elements 35 and 38. Consequently, the voltage value of the bridge voltage decreases compared to the nominal voltage value. The calculation unit 6 is accordingly configured to determine that there is a ground interruption in first ground line 19 if the voltage value of the bridge voltage decreases compared to the nominal voltage value.

[0040] If there is a ground interruption in second ground line 20, the resistance values ​​of resistor elements 35 and 38 are smaller than the resistance values ​​of resistor elements 36 and 37. Consequently, the voltage value of the bridge voltage increases compared to the nominal voltage value. The calculation unit 6 is accordingly configured to determine that there is a ground interruption in second ground line 20 if the voltage value of the bridge voltage increases compared to the nominal voltage value.

[0041] The computing unit 6 is preferably designed to prevent the function of the computing unit 5 (ie, the execution of a parking process) if there is a ground interruption in the ground line 19 or 20 .

Claims

1. A system for detecting a ground fault, comprising a controller (3) having a housing (4), in which at least one computing unit (5, 6) of the controller (3) is arranged, an electrical ground connection (13) arranged outside the housing (4), a first ground connection (19) via which the controller (3) is electrically connected to the ground connection (13), a second ground connection (20) via which the controller (3) is electrically connected to the ground connection (13), and a sensor device (21) configured to monitor a first ground current flowing through the first ground connection (19) and a second ground current flowing through the second ground connection (20), characterized in that The sensor device (21) for monitoring the first ground current and the second ground current comprises an XMR sensor (22), The XMR sensor (22) has a measuring bridge (30) with a first magnetoresistive resistor element, a second magnetoresistive resistor element, a third magnetoresistive resistor element and a fourth magnetoresistive resistor element (35, 36, 37, 38). The measuring bridge (30) comprises a first conductor (33) and a second conductor (34), wherein the first conductor (33) and the second conductor (34) are electrically connected in parallel to an inlet (31) of the measuring bridge (30) and are electrically connected in parallel to an outlet (32) of the measuring bridge (30), wherein the first conductor (33) comprises a first magnetoresistive resistor element (35) adjacent to the inlet (31) and a third magnetoresistive resistor element (37) adjacent to the outlet (32), and wherein the second conductor (34) comprises a second magnetoresistive resistor element (36) adjacent to the inlet (31) and a fourth magnetoresistive resistor element (38) adjacent to the outlet (32), The first and fourth magnetoresistive resistor elements (35, 38) are arranged adjacent to the first grounding line (19) so that the resistance value of the first magnetoresistive resistor element (35) and the resistance value of the fourth magnetoresistive resistor element (38) are affected by changes in the first grounding current; and the second and third magnetoresistive resistor elements (36, 37) are arranged adjacent to the second grounding line (20) so that the resistance value of the second magnetoresistive resistor element (36) and the resistance value of the third magnetoresistive resistor element (37) are affected by changes in the second grounding current.

2. The system according to claim 1, wherein: The magnetoresistive resistor elements (35, 36, 37, 38) are identically designed.

3. The system according to claim 1, characterized in that An evaluation unit (6) is designed to detect a bridge voltage of the measuring bridge (30) and to determine, based on the bridge voltage, whether the first ground line and / or the second ground line (19, 20) has a ground interruption.

4. The system according to claim 1, wherein: The first and fourth magnetoresistive resistor elements (35, 38) are constructed so that a change in the first grounding current affects the resistance values ​​of the first and fourth magnetoresistive resistor elements (35, 38) to the same extent; and the second and third magnetoresistive resistor elements (36, 37) are constructed so that a change in the second grounding current affects the resistance values ​​of the second and third magnetoresistive resistor elements (36, 37) to the same extent.

5. The system according to claim 1, wherein: The XMR sensor (22) is integrated into the controller (3).

6. The system according to claim 1, wherein: The XMR sensor (22) is designed without a magnetic flux concentrator.

7. The system according to claim 1, wherein: The XMR sensor (22) is designed as a GMR sensor or as a TMR sensor.

8. A motor vehicle (1) with a system (2) according to any one of the preceding claims.

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