DE102018208249A1 - Device and method for detecting defective lines and / or contacts - Google Patents

Abstract

It is a device for detecting defective lines and / or contacts between a power source, in particular a high-voltage storage, and an energy consumer, in particular an electric motor proposed, the apparatus comprising: a receiving unit for receiving a first voltage information of the power source, a second voltage information of the energy consumer and a current information of a line between the power source and the power consumer, a comparison unit for determining a voltage difference based on a comparison of the first voltage information and the second voltage information, a calculation unit for calculating a resistance value of the line based on the voltage difference and the current information and a processing unit for detecting a defect in the line if the resistance exceeds a predefined threshold.

Description

The invention relates to a device for detecting defective lines and / or contacts between a power source and an energy consumer. Furthermore, the present invention relates to a motor vehicle with such a device. Moreover, the present invention relates to a method for detecting defective lines and / or contacts between a power source and an energy consumer.

In various systems, such as in vehicles, power transmission lines are used. In order to enable reliable operation of these systems, it is necessary to ensure the correct functioning of such lines and the contact points. Overloading power transmission lines / contacts may damage the lines themselves or their associated plugs or other related systems. In the worst case, overloading may damage a thermal event, i. cause a fire.

In order to prevent this, monitoring devices can be provided which detect overloading of these lines and initiate corresponding protective measures. In previous systems, overload protection may be provided for a cable-to-connector assembly. To determine such an overload, a current-time characteristic of the weakest link in the cable-plug combination is used. This characteristic defines how long, in particular, high currents must be applied, and thus shutdown times for these high currents can be defined. In practice, the current-time characteristic is approximated by a staircase characteristic. If a maximum value is exceeded, measures against overloading are initiated. The overload protection is based on a non-defective cable / plug connection. However, if there is already a defect, an overload, which in this case can already occur at much lower currents, can not be detected. The consequence of this may be a thermal event as described above.

In order to prevent damage by thermal events in these cases, it is known to incorporate temperature sensors in the weakest link of a cable-connector assembly and to monitor them. However, additional vulnerable hardware, i. Sensors required, which must be self-monitored. This in turn increases the cost, also by additional required wiring and other measuring inputs (AD converter) for the temperature sensors in control units.

It is therefore an object of the present invention to provide improved and easy monitoring of lines in an energy-borne system.

This object is achieved by a device for detecting defective lines and / or contacts between a power source, in particular a high-voltage storage, and an energy consumer, in particular an electric motor, according to claim 1 and a method for detecting defective lines and / or contacts according to claim 10.

The device for detecting defective lines and / or contacts has a receiving unit, a comparison unit, a calculation unit and a processing unit.

First, the receiving unit receives first voltage information of the power source, that is, a voltage applied to the power source with respect to the line to the power consumer. Furthermore, the receiving unit receives a second voltage information of the energy consumer, that is, a voltage which is present in the energy consumer with respect to the line between the energy source and the energy consumer. The receiving unit also receives current information of the line between the power source and the power consumer.

The voltage information and the current information can be provided for example by controllers in the power source and the power consumer. These controllers can pick up the voltage and current of the line or receive that information from sensors. The device can be provided separately from these control units or form part of one of the control units. The transmission of the data to the device can be wireless, for example via a radio transmission, or wired, for example via a data bus.

Under a voltage information can be understood in this context, a voltage value of a voltage applied to the power source or the power consumer. The voltage information may comprise a plurality of voltage values over a specific period of time, continuously and / or as voltage values tapped at specific intervals. This applies analogously to the current information.

After receiving the first and second voltage information, the comparison unit may then determine a voltage difference based on a comparison of the first and second voltage information (FIG. U ₁ . U ₂ ), determine. Based on this voltage difference, the calculation unit can calculate a resistance value of the line. In addition to the voltage difference, the calculation unit also uses the current information of the line. Since the resistance value changes depending on a defect of the line, it can be detected from the resistance value whether there is a defect of the line.

The defect detection is thus based on an increased voltage drop between the energy source and the energy consumer (ie between or on these existing contacts and lines). The voltage drop can be achieved by simply subtracting the voltages U ₁ . U ₂ be determined.

The defect can be, for example, bad contacts in plugs, an approaching line break or a chemical or corrosive decomposition of lines / plugs. If a defect of the line was detected, i. If the resistance value exceeds a predefined threshold value, the processing unit can, for example, output a signal which gives an indication of a defect in the line.

By means of the device described above, it is possible to detect both a defect and an overload of the line and / or contact points (e.g., plugs) in the power source and / or the power consumer connected to the line without further additional sensors such as temperature sensors. The determination of an overload or a defect takes place only by calculating the relevant electrical variables based on local measured values (voltages and currents) in the energy source and the energy consumer, or in these existing control units (ECUs).

The device can be used for various systems with a power source and an energy consumer, for example, for vehicles such as land vehicles, aircraft, watercraft, agricultural or construction machinery, but also in power engineering or for energy supply systems. The energy to be transmitted may be DC or AC, which may also be multi-phase. The device can also be used for both high voltage and low voltage systems. The energy source can also be, for example, a charging station and the energy consumer is an energy storage that is charged by the charging station.

Since the voltage drop across contacts and lines is usually very small and / or the measurements of the voltages and currents may have offset errors, it is advantageous to subtract the voltages U ₁ . U ₂ to calibrate. For this purpose, the processing unit may have a calibration unit. This can perform the calibration, for example, in the idle state, ie when no current flows, because then the voltage drop across the cable-connector network is zero. The calibration voltage in this case is equal to the differential voltage U ₁ minus U ₂ ,

The apparatus may, according to one embodiment, have a first modeling unit for modeling a size proportional to the thermal energy in the cable-and-socket joint. The first modeling unit serves to detect the overload of the line. An overload of the line can lead to an increase in temperature and thus to damage and failure of the line. If this is detected in time, the protection of the line can be improved by appropriate countermeasures.

The first modeling unit can be implemented, for example, as a PT1 element, which represents a particularly simple possibility of modeling a variable proportional to the thermal energy content of the line with the aid of the current-time characteristic curve. The characteristics, i. the time constant and the maximum possible continuous current, can be derived from the current-time characteristic of the weakest link in the cable-connector composite. The output of the first modeling unit, i. the quantity proportional to the heat energy can be forwarded to the processing unit in order, if necessary, to indicate an overload of the line.

According to a further embodiment, the device has a second modeling unit for the heat energy present in the cable-plug composite. While the first modeling unit receives only the current information as input, the second modeling unit uses as inputs the first voltage information, the second voltage information, and the current information. The second modeling unit can also be implemented as a PT1 element and use the same time constant as the first modeling unit. Since the second modeling unit not only supplies the current but also the differential voltage of first and second voltage information, i. taken into account the voltage drop at the cable-connector composite, in the calculation of the present in the cable-connector composite thermal energy optionally changes in resistance due to defects, but also changes in resistivity due to the heating of the cable-connector composite are taken into account.

A change in resistivity may be considered as a function of temperature and may be accounted for by one factor - the relative resistance change due to temperature. Since the temperature is directly proportional to the thermal energy calculated in the cable-and-connector assembly, the influence of the resistivity change due to a temperature change can be eliminated by the second modeling unit to observe only the resistance changes due to defects.

In the new state of a system, the cable-connector composite can be assumed to be defect-free. The total resistance of the cable-and-connector assembly in this case is the thermal energy proportional size of the second modeling unit divided by the thermal energy proportional size of the first modeling unit divided by a factor that modifies the resistivity of the cable connector. Indicates composite. The new total resistance thus determined can be used, for example, as a reference for the monitoring by the calculation unit and the processing unit.

If there is no overload / damage in the cable / plug connection, the calculated ratio of the size of the second modeling unit, which is proportional to the heat energy, to the size of the first modeling unit, which is proportional to the heat energy, remains divided by the total new resistance and divided by the factor for a change of resistivity equal to one.

If the ratio is greater than one, this indicates an increase in the total resistance. Depending on the size of the resistance ratio, a warning may be issued or a power reduction or shutdown of the energy source or the energy consumer may be initiated.

In order to perform the calculation of the overload more accurately, the heat energy proportional output of the first modeling unit can be normalized by dividing by the maximum allowable continuous current squared. This result can then be multiplied by the current resistance ratio to easily calculate the overload more accurately.

This means that based on the output signals of both modeling units by the calculation unit and the processing unit both an overload and a defect of the line or related contacts or connectors can be determined.

By using the two modeling units, both overload protection and defect detection in the cable-plug connection between the energy source and the energy consumer can be realized.

It is also possible to model each of the connectors and the cable separately as PT1 links to refine the models represented by the modeling units or PT1 links.

The proposed device makes it possible to detect defective contacts and / or lines before they lead to further damage or danger. In addition to a mere detection of a defect or overload, the detection can be linked to an emergency concept. Depending on how high the overload and / or how extensive the defect is, it can be ensured that the system, such as a vehicle, can still be operated until a safe state has been reached. By knowing the currently calculated heat energy in the cable-plug connection, an emergency concept can be derived in which a vehicle can still be driven into the workshop, even if the cable-plug connection is defective.

Furthermore, a motor vehicle with an energy source, in particular a high-voltage accumulator, with an energy consumer, in particular an electric motor, and with a device as described above for detecting defective lines and / or contacts between the energy source and the energy consumer proposed. The motor vehicle may be, for example, an electric vehicle or a hybrid vehicle.

• Empfangen einer ersten Spannungsinformation der Energiequelle, einer zweiten Spannungsinformation des Energieverbrauchers und einer Strominformation einer Leitung zwischen der Energiequelle und dem Energieverbraucher,
• Bestimmen eines Spannungsunterschieds basierend auf einem Vergleich der ersten Spannungsinformation und der zweiten Spannungsinformation,
• Berechnen eines Widerstandswerts der Leitung basierend auf dem Spannungsunterschied und der Strominformation und
• Erkennen eines Defekts der Leitung, wenn der Widerstandswert einen vordefinierten Schwellwert überschreitet.

According to a further aspect, a method for detecting defective lines and / or contacts between a power source, in particular a high-voltage storage, and an energy consumer, in particular an electric motor proposed. The method comprises the following steps:

• Receiving a first voltage information of the energy source, a second voltage information of the energy consumer and a current information of a line between the energy source and the energy consumer,
• Determining a voltage difference based on a comparison of the first voltage information and the second voltage information,
• Calculating a resistance value of the line based on the voltage difference and the current information and
• Detecting a line failure when the resistance exceeds a predefined threshold.

Determining the voltage difference may include determining a calibration value. In this way, a very small difference voltage can be calculated more accurately and an offset measurement error can be eliminated. Furthermore, measures can be taken to reduce quantization errors if the quantization levels are too large compared to the differential voltages to be measured.

The embodiments and features described for the proposed device apply accordingly to the proposed method.

Furthermore, a computer program product is proposed, which has a program code which is adapted to cause the execution of the method as explained above on a computer.

A computer program product, such as a computer program means may, for example, be used as a storage medium, e.g. Memory card, USB stick, CD-ROM, DVD, or even in the form of a downloadable file provided by a server in a network or delivered. This can be done, for example, in a wireless communication network by transmitting a corresponding file with the computer program product or the computer program means.

Further possible implementations of the invention also include not explicitly mentioned combinations of features or embodiments described above or below with regard to the exemplary embodiments. The skilled person will also add individual aspects as improvements or additions to the respective basic form of the invention.

Further advantages and advantageous embodiments are given in the description, the drawings and the claims. In particular, the combinations of features given in the description and in the drawings are purely exemplary, so that the features can also be present individually or otherwise combined.

In the following, the invention will be described in more detail with reference to embodiments illustrated in the drawings. Here, the embodiments and the combinations shown in the embodiments are purely exemplary and are not intended to define the scope of the invention. This is defined solely by the appended claims.

• 1: ein schematisches Blockschaltbild einer Energiequelle und eines Energieverbrauchers; und
• 2: ein schematisches Blockschaltbild einer Vorrichtung zum Erkennen defekter Leitungen und/oder Kontakte zwischen der Energiequelle und dem Energieverbraucher.

Show it:

• 1 a schematic block diagram of a power source and an energy consumer; and
• 2 : A schematic block diagram of a device for detecting defective lines and / or contacts between the power source and the power consumer.

In the following, the same or functionally equivalent elements are identified with the same reference numerals.

1 shows an energy source 2 , For example, a high-voltage storage, and an energy consumer 4 , For example, an electric motor. These are each a plug or contact 6 . 8th and a wire or cable 10 interconnected to energy from the energy source 2 to the energy consumer 4 to deliver. A control of the energy source 2 and the energy consumer 4 takes place via respective control units 12 . 14 For example, via a bus 16 can communicate with each other.

In order to enable reliable operation of the entire system, it is necessary to ensure the correct functioning of the line 10 and the plug 6 . 8th sure. In case of overload of the so-called cable-connector composite, ie the plug 6 . 8th and the line 10 , can the lead 10 yourself or the associated plug 6 . 8th or the energy source 2 and the energy consumer 4 to be damaged. Such damage can be caused, for example, by thermal events such as a fire in the pipe 10 , which occur due to the overload.

To prevent this, a device can 20 be provided for detecting defective lines and / or contacts, as in 2 is shown. The device 20 can in one of the controllers 12 . 14 integrated or arranged externally to these.

The device 20 has a receiving unit 22 on. This receiving unit 22 initially receives a first voltage information U ₁ the source of energy 2 that is, a voltage that is in the energy source 2 in terms of the line 10 to the energy consumer 4 is applied. Furthermore, the receiving unit receives 22 a second voltage information U ₂ of the energy consumer 4 that is a voltage that is in the energy consumer 4 in relation on the line 10 between the energy source 2 and the energy consumer 4 is applied. In addition, the receiving unit receives 22 a stream information I the line 10 between the energy source 2 and the energy consumer 4 ,

The voltage information U ₁ . U ₂ and the current information I For example, from the controllers 12 . 14 to be provided. These controllers 12 . 14 can the tensions U ₁ . U ₂ and the stream I tap or receive this information from sensors and to the device 20 hand off.

The current information I can be attached to a first and a second modeling unit 24 . 26 to get redirected. The voltage information U1 . U2 can contact the second modeling unit 26 to get redirected. Both the first and second modeling units 24 . 26 simulate a value proportional to the heat energy or a heat energy in the cable-plug combination. The modeling units 24 . 26 can be implemented as a PT1 element.

The first modeling unit 24 is used to model a value proportional to the thermal energy in the cable-plug composite using the current information I , The output of the first modeling unit 24 can be used to detect the overload of the line 10 be used. Because an overload of the line 10 to a temperature increase and thus to a damage and a failure of the line 10 lead, it is necessary to detect this in order to be able to take timely appropriate countermeasures. If the calculated heat energy approaches or exceeds a threshold value, this can be considered as an overload on the line 10 be interpreted.

The output of the first modeling unit 24 is sent to a processing unit 32 be forwarded, which can output a signal to overload the line 10 display.

The second modeling unit 26 serves to model the actual heat energy using the first voltage information U ₁ , the second voltage information U ₂ and the current information I , The output of the second modeling unit 26 can be connected to a comparison unit 28 to get redirected. In the calculation unit 30 a temperature dependence of the resistivity is eliminated, so that by means of the comparison unit 28 a change in resistance of the plug-line network can be determined due to a defect.

From the output signals of the first modeling unit 24 and the second modeling unit 26 can in the calculation unit 30 the resistance value of the cable / plug connection can be calculated. Optionally, in the new state of a system, the resistance can be calculated under certain conditions during an initialization run and stored as a reference value. The reference value can later be compared by continuous calculation of resistance increase.

As the resistance varies depending on a defect of the line 10 changes, it can be detected by the resistance value, whether a defect of the line 10 is present.

Became a defect of the line 10 detected, ie the resistance exceeds a predefined threshold, or was an overload of the line 10 detected, the processing unit 32 For example, output a signal that gives an indication of a defect or overload of the line.

By using the two modeling unit 24 . 26 can be easily detected, whether it is an overload of the line 10 or a defect of the line 10 or the contacts 6 . 8th is. The first modeling unit 24 serves to detect the overload of the line 10 and the second modeling unit 26 serves to detect a defect. Additional temperature sensors or other sensors are not needed.

LIST OF REFERENCE NUMBERS

2

energy

4

energy consumers

6

plug

8th

plug

10

management

12

control unit

14

control unit

16

bus

20

device

22

receiver unit

24

first modeling unit

26

second modeling unit

28

comparing unit

30

calculation unit

32

processing unit

I

current information

U ₁ , U ₂

voltage information

Claims (10)

Device (20) for detecting defective lines (10) and / or contacts between a power source (2), in particular a high-voltage storage, and an energy consumer (4), in particular an electric motor, wherein the device (20) comprises: a receiving unit (22) for receiving a first voltage information (U ₁ ) of the energy source (2), a second voltage information (U ₂ ) of the energy consumer (4) and a current information (I) of a line (10) between the energy source (2) and the energy consumer (4) a comparison unit (28) for determining a voltage difference based on a comparison of the first voltage information (U ₁ ) and the second voltage information (U ₂ ), a calculation unit (30) for calculating a resistance value of the line (10) based on the voltage difference and Current information (I) and a processing unit (32) for detecting a defect of the line (10) when the resistance value exceeds a predefined threshold exceeds ell value. Device after Claim 1 wherein the comparison unit (28) comprises a calibration unit for determining a calibration value. Device after Claim 1 or 2 with a first modeling unit (24) for modeling a signal proportional to a thermal energy of the line (10) and for applying the signal to the current information (I). Device after Claim 3 , wherein the first modeling unit (24) is adapted to detect an overload of the line (10). Device after Claim 3 or 4 wherein the first modeling unit (24) is a PT1 member. Apparatus according to any one of the preceding claims, comprising a second modeling unit (26) for modeling a signal proportional to the thermal energy in the duct (10) and applying the signal to the first voltage information (U ₁ ), the second voltage information (U ₂ ) and Current information (I). Device after Claim 6 wherein the second modeling unit (26) is adapted to eliminate a temperature dependence of the current value (I). Device after Claim 6 or 7 wherein the calculation unit (30) is configured to calculate the resistance value of the line (10) based on the voltage difference and an output of the second modeling unit (26). Motor vehicle with an energy source (2), in particular a high-voltage accumulator, with an energy consumer (4), in particular an electric motor, and with a device (20) for detecting defective lines (10) and / or contacts between the energy source (2) and the energy consumer (4) according to one of the preceding claims. Method for detecting defective lines (10) and / or contacts between a power source (2), in particular a high-voltage store, and an energy consumer (4), in particular an electric motor, the method comprising: receiving first voltage information (U ₁ ) of the energy source ( 2), second voltage information (U ₂ ) of the energy consumer (4) and current information (I) of a line (10) between the energy source (2) and the energy consumer (4), determining a voltage difference based on a comparison of the first voltage information ( U ₁ ) and the second voltage information (U ₂ ), calculating a resistance value of the line (10) based on the voltage difference and the current information (I) and detecting a defect of the line (10) when the resistance value exceeds a predefined threshold value.

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