Method and device for determining a component of an impairment of an on-board power system

Abstract

This invention relates to a device for identifying damage to components of an onboard electrical system in a motor vehicle; wherein the onboard electrical system comprises a plurality of different components, each contributing to the total Y capacitance of the onboard electrical system. The device is configured to determine an estimate of the total Y capacitance of the onboard electrical system. The device is further configured to identify damaged components of the onboard electrical system based on the determined estimate and based on a capacitance model of the onboard electrical system; wherein the capacitance model illustrates how the total Y capacitance of the onboard electrical system is composed of multiple individual Y capacitances of the respective plurality of components.

Description

Technical Field

[0001] This invention relates to a method and corresponding apparatus for determining and / or identifying damage to components of an onboard electrical system in a motor vehicle. Background Technology

[0002] Electric vehicles include drive motors that operate using electrical energy from an energy storage device. The AC voltage used to operate the drive motor is generated by an inverter based on a high-voltage DC voltage supplied by the energy storage device. Furthermore, when using a current-driven drive motor, an excitation voltage for the drive motor rotor can be generated from the DC voltage of the energy storage device using a DC transformer. Additionally, electric vehicles typically have one or more additional power consumers, such as air conditioning units, which operate based on the high-voltage DC voltage.

[0003] Energy storage devices, inverters, one or more high-voltage power consumers, and / or DC transformers are part of an onboard electrical network used to power the drive motor of a motor vehicle. To meet electromagnetic compatibility (EMC) requirements, the onboard electrical network typically has Y capacitors between each pole or potential of the onboard electrical network and the vehicle ground. Furthermore, different components of the onboard electrical network typically have parasitic capacitances that contribute to the total Y capacitance between each pole or potential of the onboard electrical network and the vehicle ground. Summary of the Invention

[0004] The technical task involved in this document is to identify damage to components of the (high-voltage) onboard electrical system of a motor vehicle in an efficient, accurate and reliable manner.

[0005] This task is accomplished by each of the independent claims. Furthermore, advantageous embodiments are described in the dependent claims. It is noted that additional features of a claim dependent on an independent claim can form an invention independent of all combinations of features of the independent claim, either without the features of the independent claim or in combination with only a portion of the features of the independent claim. This invention can be the technical solution of the independent claim, divisional application, or subsequent application. This also applies to the technical teachings described in the specification, which can form an invention independent of the features of the patent claims.

[0006] According to one aspect, a device for identifying damage to components of an onboard electrical system in a motor vehicle is described. Examples of damage to the components include breakage of the component or disconnection of the component from the onboard electrical system.

[0007] The vehicle electrical network can have an electrical (particularly electrochemical) energy storage device configured to provide electrical energy with a defined vehicle electrical network voltage (i.e., DC voltage). The vehicle electrical network voltage is typically in the high-volt range of 60V or higher, particularly 300V or higher. This electrical energy can be provided to operate the drive motor of the vehicle. The energy storage device typically has a first pole (e.g., positive) and a second pole (e.g., negative), through which the vehicle electrical network voltage is applied and provides electrical energy.

[0008] The vehicle-mounted electrical network may also have a first potential conductor and a second potential conductor, which are respectively (currently grounded) coupled to the first and second terminals of the energy storage device. Electrical energy from the energy storage device can be supplied to an inverter via these potential conductors, which is configured to generate a multiphase AC voltage for the (drive) motor of the vehicle.

[0009] A typical vehicle electrical network includes a first Y capacitor and a second Y capacitor. The first Y capacitor can be positioned between a first potential conductor and a reference potential, particularly the vehicle ground, and the second Y capacitor can be positioned between a second potential conductor and the reference potential. These Y capacitors are used to meet EMC requirements.

[0010] The vehicle-mounted electrical network comprises multiple distinct components, each contributing to the total Y capacitance of the network. The total Y capacitance may include the capacitance of a first or second Y capacitor. Furthermore, the total Y capacitance may include multiple individual Y capacitors from the respective components of the vehicle-mounted electrical network. This document typically discusses the Y capacitance relating to the Y capacitance between a potential conductor (e.g., a positive or negative conductor) and a reference potential (e.g., vehicle ground).

[0011] The plurality of components may include:

[0012] •Electrical energy storage devices, particularly electrochemical energy storage devices, which are configured to store and supply electrical energy to the vehicle-mounted electrical grid;

[0013] • An electric motor configured to drive a motor vehicle;

[0014] • An inverter configured to generate phase current for operating a motor based on the on-board grid voltage; and / or

[0015] • One or more power supplies configured to operate by directly utilizing electrical energy from the vehicle's electrical grid (the vehicle's electrical grid voltage can be directly applied to the one or more power supplies).

[0016] Each component can operate based on the on-board electrical grid voltage applied between a first potential conductor and a second potential conductor. Furthermore, each component can have a housing coupled to a reference potential via a potential balancing conductor (conductively grounded). Alternatively or supplementarily, the component's housing can be coupled to the reference potential via a shield of a conductor leading to or away from the component. A first end of the conductor can be disposed on the component, and the shield of the conductor can be connected at the first end to the component's housing (conductively grounded). The opposite second end of the conductor can be disposed on another component of the on-board electrical grid, and the shield of the conductor can be connected at the second end to the housing (conductively grounded) of that other component. Thus, the connection of the component's housing to the reference potential can be achieved indirectly via the shield of the conductor (and via the housing of another component).

[0017] The device can be configured to identify damage as occurring when the housing of a component is separated from the reference potential (and therefore there is no conductive connection between the housing and the reference potential, neither via a potential balancing conductor nor via the shielding of the electrical wires of the vehicle's electrical grid).

[0018] The device is configured to determine an estimate of the total Y capacitance of the vehicle electrical network. For this purpose, the time history of the voltage at the measuring resistance of the insulation monitoring unit (either symmetrical or asymmetrical) can be determined based on the insulation monitoring unit (wherein, for example, the time history is determined within the framework of insulation resistance monitoring). The estimate of the total Y capacitance can then be determined efficiently and accurately based on the time history of the voltage.

[0019] The device is also configured to identify damaged components (i.e., one of a plurality of components of the on-board electrical network) of the vehicle electrical network based on determined estimates and a capacitance model of the on-board electrical network. Damage to a component may include damage to, and in particular, an interruption of, a potential balance conductor, through which the component's housing is electrically connected to a reference potential of the vehicle electrical network. Alternatively or additionally, damage to a component may include impairment of the component's function (in particular, affecting the function of the component's Y-cell capacitor).

[0020] A capacitance model can illustrate and / or model and / or depend on how the total Y capacitance of an onboard electrical network is composed of multiple Y individual capacitors from various components. The capacitance model can be predetermined, for example, determined experimentally and / or trained. The capacitance model may, for example, include experimentally determined characteristic data and / or a family of characteristic curves.

[0021] The device may also be configured to implement at least one measure regarding the identified component. Example measures include:

[0022] • Issue prompts, especially via the user interface of a motor vehicle;

[0023] • Input the error into the vehicle's error memory; and / or

[0024] • Intervene in the operation of motor vehicles.

[0025] Therefore, an apparatus is described that analyzes the total Y capacitance of an onboard electrical network to identify damaged components, particularly those with damaged potential balance conductors, in a highly efficient and reliable manner.

[0026] The capacitance model can specify a target value for the total capacitance of Y (which should exist if no components are damaged). The device can be configured to compare the determined estimate with the target value. Based on this comparison, it can then be reliably determined whether, and if necessary, at least one of the plurality of components is damaged.

[0027] The device can be configured to determine the deviation (specifically, the difference) between a determined estimate and a target value of the total Y capacitance of the vehicle electrical network. Damaged components among the plurality of components can then be identified in a particularly precise manner based on the deviation and on a capacitance model.

[0028] This device can be specifically configured to compare the determined deviation with multiple Y-cell capacitors of corresponding components. The damaged components can then be reliably identified based on the comparison. Specifically, components with Y-cell capacitors corresponding to (particularly equivalent to) the determined deviation can be identified.

[0029] According to another aspect, an on-board electrical network for a motor vehicle is described. This on-board electrical network includes several different components, each contributing to the total Y capacitance of the on-board electrical network. Furthermore, the on-board electrical network includes the devices described in this document.

[0030] According to another description, a (road) motor vehicle (particularly a passenger car, truck, bus, or motorcycle) includes the equipment described in this document and / or the on-board electrical network described in this document.

[0031] According to another aspect, a method for identifying damage to components of an onboard electrical network of a motor vehicle is described, wherein the onboard electrical network includes multiple different components, each of which contributes to the total Y capacitance of the onboard electrical network.

[0032] This method includes determining an estimate of the total Y capacitance of the vehicle electrical network. Furthermore, this method includes identifying damaged components of the vehicle electrical network based on the determined estimate and a capacitance model of the vehicle electrical network. The capacitance model can describe and / or depend on how the total Y capacitance of the vehicle electrical network is composed of multiple Y individual capacitors from corresponding components.

[0033] It should be noted that aspects described in connection with the device, particularly claims described in connection with the device, can also be applied to the method as corresponding method features.

[0034] According to another aspect, a software (SW) program is described. The SW program can be configured to be implemented on a processor (e.g., on a vehicle controller), and thereby implement the methods described in this document.

[0035] According to another aspect, a storage medium is described. This storage medium may include a Service Module (SW) program configured to implement, and thereby implement, the methods described in this document on a processor.

[0036] It should be noted that the methods, apparatus, and systems described in this document can be used not only individually but also in combination with other methods, apparatus, and systems described in this document. Furthermore, any aspect of the methods, apparatus, and systems described in this document can be combined with each other in various ways. In particular, the features of the claims can be combined with each other in various ways. Additionally, features listed in parentheses should be understood as optional features. Attached Figure Description

[0037] The present invention will now be described in more detail with reference to embodiments. Wherein:

[0038] Figure 1a Exemplary components of a vehicle having a drive motor are shown;

[0039] Figure 1b An exemplary insulation monitoring unit is shown;

[0040] Figure 2 An exemplary voltage history is shown during the discharge of the second Y capacitor;

[0041] Figure 3 An exemplary capacitor model for an onboard electrical network is shown; and

[0042] Figure 4 A flowchart illustrating an exemplary method for identifying damaged components of an onboard electrical network is shown. Detailed Implementation

[0043] As stated at the beginning, this document relates to identifying potential damage to components of a motor vehicle's onboard electrical system in an efficient and reliable manner. In this regard, Figure 1aExemplary components of a vehicle 140 are shown, including a motor 103 for driving the vehicle 140. The motor 103 is coupled to one or more wheels 141 of the vehicle 140 to drive the one or more wheels 141 and thus drive the vehicle 140. The motor 103 operates using electrical energy from an electrical energy storage device, particularly an electrochemical energy storage device 130. The energy storage device 130 may be configured to provide direct current with a defined direct current voltage.

[0044] Vehicle 140 has an inverter 100 configured to generate phase voltages and / or phase currents for different phases of motor 103 based on DC voltage from energy storage 130. Inverter 100 can be operated via (control) device 101 of vehicle 100.

[0045] Inverter 100 can be, for example, in Figure 1b As shown, the first potential wire 151 is electrically connected to the energy storage device 130 via potential wires 151 and 152. The first potential wire 151 can lead to a first terminal of the energy storage device 130, and the second potential wire 152 can lead to a second terminal of the energy storage device. The first potential wire 151 can be at a first potential (e.g., at a positive potential, such as high volts + or HV+), while the second potential wire 152 can be at a second potential (e.g., at a negative potential, such as HV-). The potential wires 151 and 152 connected to the energy storage device 130 can be decoupled from the inverter 100 via wire switching elements 159 (e.g., via MOSFETs).

[0046] In addition to the inverter 100 Figure 1b Also shown is a DC transformer 110 configured to generate an excitation voltage for the rotor of the motor 103 based on a DC voltage provided by the energy storage device 130, i.e., based on the on-board grid voltage.

[0047] Each potential conductor 151 and 152 should have a relatively high insulation resistance R relative to the vehicle ground 153 (usually relative to the reference potential) for the safe operation of the motor vehicle 100. ISO+ and R ISO- The insulation resistance R can be reduced due to defects in the energy storage device 130 and / or due to defects in one of the potential conductors 151 and 152 and / or due to defects in the inverter 100. ISO+ and R ISO- Vehicle 100 may have an insulation monitoring unit 150 for monitoring insulation resistance. The insulation monitoring unit 150 may be configured to specifically determine a first insulation resistance R between a first potential conductor 151 and ground (typically a reference potential) 153. ISO+ and the second insulation resistance R between the second potential conductor 152 and the ground 153 ISO-For this purpose, a measuring voltage (corresponding, for example, to the potential difference between the respective potential conductors 151, 152 and the ground 153) can be applied, and the resulting measuring current can be detected. The respective insulation resistance can then be determined from the ratio between the measuring voltage and the measuring current.

[0048] Figure 1b An exemplary (asymmetric) insulation monitoring unit 150 is shown, which advantageously has only a single measuring switching element 155 so as to be able to measure the two insulation resistances R. ISO+ and R ISO- Furthermore, the insulation monitoring unit 150 has an activation switch element 154 that can be closed to enable the measurement of insulation resistance R. ISO+ and R ISO- .

[0049] The insulation monitoring unit 150 has a first series circuit for measuring resistances Ra and Rb, which can be connected in parallel with the first insulation resistance R (by closing the activation switch element 154). ISO+ Arrangement. Furthermore, the insulation monitoring unit 150 has a second series circuit for measuring resistances Rc and Rd, which can be connected in parallel with the second insulation resistance R (by closing the activation switch element 154). ISO- Arrangement. Preferably, the first resistor series circuit and the second resistor series circuit have the same resistance value (i.e., Ra + Rb = Rc + Rd).

[0050] The current can be measured based on the voltage across resistor Rd caused by the current flowing through Rd (via measuring unit 156). The measuring switch element 155 is configured to directly couple or decouple the midpoint between the two resistors Ra and Ra in the first resistor series circuit to the second potential wire 152.

[0051] Insulation resistance R ISO+ and R ISO- Measurements can be initiated by closing the activation switch element 154, such that the node between the two resistors in series is coupled to ground 153 (typically coupled to a reference potential).

[0052] The measuring unit 156 can determine the measuring current for two measurement scenarios or switch states: "measuring switch element 155 closed" and "measuring switch element 155 open". This measuring current can be used to determine the insulation resistance R. ISO+ and R ISO- The value of .

[0053] Energy storage device 130 and potential conductors 151, 152 are part of the (high-volt) on-board electrical network of vehicle 100, which is configured to supply electrical energy to drive motor 103 of vehicle 100. To meet EMC requirements, the on-board electrical network typically includes a Y capacitor, particularly a first Y capacitor C between the first potential conductor 151 and the reference potential 153. y+ The second Y capacitor C between the second potential conductor 152 and the reference potential 153 y- .

[0054] The on-board electrical network may also include, if necessary, one or more power consumers 170 arranged between potential conductors 151, 152, and these power consumers typically have (parasitic) Y-capacitors, specifically a first Y-capacitor between the first potential conductor 151 and the reference potential 153, and a second Y-capacitor between the second potential conductor 152 and the reference potential 153. Furthermore, the inverter 100 typically also has (parasitic) first and second Y-capacitors.

[0055] The Y capacitor is discussed exemplarily below, which may refer to a first Y capacitor (between the first potential conductor 151 and the reference potential 153) and / or a second Y capacitor (between the second potential conductor 152 and the reference potential 153).

[0056] Therefore, the vehicle-mounted electrical network can have a total Y capacitance, which can be composed of the capacitance of the Y capacitor and the (parasitic) capacitance of one or more components 151, 152, 100, 103, 110, 170 of the vehicle-mounted electrical network.

[0057] Within the framework of insulation resistance monitoring, the (voltage) measurements can be used to determine an estimate of the total Y capacitance in an efficient and accurate manner. For this purpose, as exemplarily... Figure 2 As shown, the second Y capacitor C can be detected and evaluated (according to measurement unit 156). y- The voltage at point 200 is recorded over time 221. The closing of the measuring switch element 155 (at time 211) within the framework of the insulation resistance check causes the second Y capacitor C to... y- The (partial) discharge and voltage history 221 decreases, wherein voltage 200 decreases from a first voltage 201 to a second voltage 202. This occurs from the second Y capacitor C. y- The charge flows into the first Y capacitor C here. y+ It is then charged.

[0058] The voltage history 221 can be approximated by a reference curve 222 (e.g., an exponential curve or a hyperbola) with a time constant. The estimated value of the total Y capacitance can then be determined based on the time constant (considering the one or more resistances of the insulation monitoring unit 150 and / or considering the insulation resistance).

[0059] As explained above, the total Y capacitance consists of multiple individual capacitors from various components of the vehicle's electrical network. Example components are:

[0060] • Y capacitor C y ;

[0061] • One or more power supplies 170;

[0062] • Inverter 100;

[0063] • Motor 103; and / or

[0064] • Energy storage device 130.

[0065] The individual capacitances of each component can be measured in advance to determine the capacitance model 300 of the total Y capacitance of the vehicle electrical network (see [reference]). Figure 3 The capacitor model 300 illustrates how the total Y capacitance is composed of multiple Y individual capacitors 302 of corresponding multiple components 301 of the vehicle electrical network.

[0066] During operation of the vehicle-mounted electrical network, an estimated value of the total Y capacitance can be measured (as described in this document). Based on the capacitance model 300 for the total Y capacitance, it can be identified that the estimated value of the total Y capacitance is lower than a predetermined target value. Furthermore, based on the capacitance model 300, and particularly on the plurality of individual Y capacitors 302, it can be determined which component 301 of the vehicle-mounted electrical network is damaged. Specifically, it can be determined which one or more individual Y capacitors 302 do not contribute to the total Y capacitance. Based on the one or more identified individual Y capacitors 302, conclusions can be drawn regarding the one or more components 301 associated with them.

[0067] As described at the beginning, the motor vehicle 140 has an insulation monitoring device for monitoring insulation resistance. The insulation monitoring device measures the insulation resistance between HV potentials 151, 152 and ground 153. If the measured insulation resistance is below one or more resistance thresholds, one or more safety measures may be triggered (such as issuing a warning, limiting availability, and / or completely shutting down the vehicle's electrical system).

[0068] The housings of each HV component 170, 301 are connected to the ground potential 153 via so-called PA (potential balance) conductors. This can be a direct threaded connection or a cable. Typically, only relatively high costs are required to check whether the individual PA conductors are correctly connected and / or whether the predetermined resistance values ​​of the individual PA conductors are maintained during their service life. Errors in connecting the individual components 170, 301 may occur, for example, due to faulty components, deviations in the manufacturing process, or after maintenance via component replacement.

[0069] The presence of PA conductors in individual components 170, 301 can be checked based on the estimated total Y capacitance. Each HV component 170, 601 has a single Y capacitance between HV potentials 151, 152 and ground potential 153, and therefore contributes to the total Y capacitance of the HV system (i.e., the vehicle electrical network). Capacitive losses in the total Y capacitance can be identified based on the determined estimated total Y capacitance. Furthermore, faulty components 170, 301 can be inferred based on the value of the capacitive losses, since each HV component 170, 301 contributes to the total Y capacitance by a fairly certain and known amount (i.e., the determined single Y capacitance 302).

[0070] For example, an estimate of the total Y capacitance of the HV system of vehicle 140 can be determined after production of vehicle 140. Based on the estimate, it can be identified that the capacitance is below a predetermined threshold. By comparing this estimate with a family of characteristic curves (i.e., with capacitance model 300), in which each HV component 301 stores its own preset capacitance value—which may include tolerances—(i.e., its own individual Y capacitance 302), it can be identified that the estimate reduces the predetermined Y capacitance value of the determined component 301 (e.g., motor 103). A check of the potential balance conductor and / or the function of the identified component 301 can then be initiated.

[0071] Figure 4 A flowchart is shown of a (possibly computer-implemented) method 400 for identifying damage to components 301 of the onboard electrical system of a motor vehicle 140. The onboard electrical system includes multiple different components 301, each contributing to the total Y capacitance of the onboard electrical system. Method 400 can be implemented by device 101 of the motor vehicle 140.

[0072] Method 400 includes determining an estimate of the total Y capacitance of the 401 on-board electrical network (based on the method described in this document).

[0073] Furthermore, method 400 includes identifying 402 damaged components 301 of the on-board electrical network based on the determined estimates and on a capacitance model 300 of the on-board electrical network. The capacitance model 300 can illustrate and / or model how the total Y capacitance of the on-board electrical network is composed of multiple Y individual capacitors 302 of the corresponding multiple components 301. The capacitance model 300 can exist, for example, in the form of one or more families of characteristic curves and / or characteristic curves. Alternatively or additionally, the capacitance model 300 can exist in the form of a model trained via machine learning (e.g., having one or more neural networks).

[0074] Method 400 can be repeated at a series of successive time points (e.g., periodically). This enables persistent and reliable monitoring of the vehicle's electrical grid.

[0075] Analysis of the total capacitance of Y enables the efficient and reliable identification of damage to component 301 in the HV vehicle electrical network.

[0076] This invention is not limited to the embodiments shown. In particular, it should be noted that the specification and drawings are intended to illustrate the principles of the proposed methods, apparatus, and systems only.

Claims

1. A device (101) for identifying damage to a component (301) of the onboard electrical network of a motor vehicle (140); wherein, The vehicle-mounted electrical network includes multiple different components (301), each contributing to the total Y capacitance of the vehicle-mounted electrical network; wherein the device (101) is configured to: Determine the estimated value of the total Y capacitance of the vehicle-mounted electrical network; Based on the determined estimates and based on the capacitance model (300) of the vehicle electrical network, the damaged components (301) of the vehicle electrical network are identified; wherein the capacitance model (300) illustrates how the total Y capacitance of the vehicle electrical network is composed of multiple Y single capacitors (302) of the corresponding multiple components (301).

2. The device (101) according to claim 1, wherein, The capacitance model (300) describes the target value of the total capacitance of Y; and The device (101) is configured to: —Compare the determined estimated value with the target value; and —Based on the comparison, it is determined that at least one of the plurality of components (301) has damage.

3. The device (101) according to any one of the preceding claims, wherein, The device (101) is configured to: Determine the deviation between the estimated and target values ​​of the total Y capacitance of the vehicle-mounted electrical network; and Based on the deviation and based on the capacitance model (300), the damaged component (301) among the plurality of components (301) is identified.

4. The device (101) according to claim 3, wherein, The device (101) is configured to: The determined deviation is compared with the plurality of Y-cell capacitors (302) of the corresponding plurality of components (301); and The damaged component (301) is identified based on the comparison.

5. The device (101) according to claim 4, wherein, The device (101) is configured to identify a component (301) having a Y single capacitor (302) corresponding to a determined deviation.

6. The device (101) according to any one of the preceding claims, wherein, The device (101) is configured to: The time history (221) of the voltage (200) at the measuring resistor of the insulation monitoring unit (150) is determined based on the insulation monitoring unit (150); and The estimated value of the total capacitance of Y is determined based on the time history (221) of the voltage (200).

7. The device (101) according to any one of the preceding claims, wherein, The device (101) is configured to implement at least one measure concerning the identified component (301); and The measures specifically include: —Prompts are issued, particularly via the user interface of the vehicle (140); — Input the error into the error memory of the vehicle (140); and / or —Intervene in the operation of motor vehicles (140).

8. The device (101) according to any one of the preceding claims, wherein, The plurality of components (301) include An electrical energy storage device (130), particularly an electrochemical energy storage device, is configured to store and supply electrical energy for an on-board electrical grid; An electric motor (103) configured to drive a motor vehicle (140). Inverter (100), the inverter is configured to generate phase current for operating motor (103) based on grid voltage of on-board power grid; and / or One or more power supplies (170) configured to operate using electrical energy from the vehicle's electrical grid.

9. The device (101) according to any one of the preceding claims, wherein, The vehicle electrical grid has a vehicle electrical grid voltage of 60V or higher, particularly in the high-volt range of 300V or higher.

10. The device (101) according to any one of the preceding claims, wherein, The vehicle-mounted electrical network has a first potential conductor (151), a second potential conductor (152), and a reference potential (153). Each component (301) operates based on the on-board grid voltage applied between the first potential conductor (151) and the second potential conductor (152); and Each component (301) has a housing, which is coupled to a reference potential (153) via a potential balancing conductor.

11. The device (101) according to any one of the preceding claims, wherein, Damage to component (301) includes: Damage to, and particularly interruption of, the potential balancing conductor, by which the housing of the component (301) is electrically connected to the reference potential (153) of the on-board electrical network; and / or Damage to the function of the component (301).

12. A method (400) for identifying damage to a component (301) of an onboard electrical network of a motor vehicle (140); wherein, The vehicle-mounted electrical network includes multiple different components (301), each of which contributes to the total Y capacitance of the vehicle-mounted electrical network. The method (400) includes: Determine the estimated value of the total Y capacitance of the on-board electrical network (401); and Based on the determined estimates and based on the capacitance model (300) of the vehicle electrical network, identify (402) the damaged components (301) of the vehicle electrical network; wherein the capacitance model (300) illustrates how the total Y capacitance of the vehicle electrical network is composed of multiple Y single capacitors (302) of the corresponding multiple components (301).

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