Power distribution device and use thereof for distributing electrical power in a vehicle

Abstract

The invention relates to a power distribution device (10) for distributing electrical power in a DC voltage supply of a vehicle, comprising an input connection (20) for a DC voltage source (BAT), output connections (30-1, 30-2) for electrical loads (L1, L2), a distribution line assembly (40) that is connected or can be connected to the input connection (20) and to the output connections (30-1, 30-2), a semiconductor switching element (42) that is provided in the distribution line assembly (40) so as to be paired with one (30-2) of the output connections (30-1, 30-2) and can be actuated by means of a switching signal (SS), which can be applied to a control connection (G), in order to be able to switch off a current flow by opening the switching element (42) in the event of an excessively high current flowing over the relevant output connection (30-2), a driver circuit (50) for receiving a driver input signal (TES) and outputting the switching signal (SS) corresponding to the driver input signal (TES), and a control device (60, 70, 80, 90, 100) for monitoring the aforementioned current flow and for generating the driver input signal (TES) while taking into account said current flow. In order to be able to detect error events, the control device (60, 70, 80, 90, 100) is also designed to monitor the correspondence between the driver input signal (TES) and the switching signal (SS) and, in the event of a non-correspondence, to generate and output an error signal (FS).

Description

[0001] 202400671

[0002] 1

[0003] Description

[0004] Power distribution device, and its use for distributing electrical power in a vehicle

[0005] The present invention relates to a power distribution device and further to the use of such a device for distributing electrical power in a DC power supply of a vehicle.

[0006] A power distribution device is used, for example, by battery electric vehicles (BEVs) and hybrid electric vehicles (HEVs) and is often referred to in this context as a "Power Distribution Unit" (PDU). These devices serve to distribute electrical power in the vehicle's high-voltage direct current (HVDC) power supply, which in this context refers to voltages of more than 100 V or even more than 400 V, such as typically around 800 V. From this HVDC power supply, high-power electrical consumers in the vehicle can be supplied, such as (as a "main load") an inverter to power an AC motor located in the vehicle's drivetrain, and (as "secondary load(s)") at least one other inverter or at least one electric heating device.

[0007] To prevent excessive current flow through an output terminal of the power distribution device in the event of a fault, newer power distribution devices use so-called electronic fuses, also known as efuses, instead of traditional fuses. These electronic fuses contain a semiconductor switching element.

[0008] However, due to its complexity, an electronic fuse implemented with a semiconductor switching element has an inherently lower reliability than a conventional fuse. Therefore, it would be desirable to be able to monitor the functionality of the electronic fuse or the semiconductor switching element in order to take appropriate measures to maintain the safety of the vehicle and its occupants in the event of a detected fault. 202400671

[0009] 2

[0010] The object of the present invention is to provide a power distribution device with an electronic fuse that enables the detection of fault events which are relevant to the functionality of the electronic fuse.

[0011] The problem is solved by the features of the independent patent claims. Advantageous embodiments of the invention are characterized in the dependent claims.

[0012] According to a first aspect, the problem is solved by a power distribution device that has an input terminal for connecting a DC voltage source (e.g., a traction battery) and several output terminals for connecting respective electrical loads (e.g., an inverter). Furthermore, the device includes a distribution line arrangement (e.g., a two-pole arrangement) that is connected or connectable to the input terminal on one side and to the output terminals on the other. The device also includes (at least) one semiconductor switching element (e.g., a power MOSFET) that is assigned to one of the output terminals and is arranged in the distribution line arrangement, and which is connected to a control terminal (e.g., a controller).The gate of a FET) of the semiconductor switching element can be controlled by a switching signal applied to it, such that in the event of an excessively high current flow via the relevant output terminal, the current flowing via this output terminal can be switched off by opening the semiconductor switching element controlled by the switching signal.

[0013] For example, it may be provided that the current flowing through the relevant output terminal is measured by means of a measuring resistor (shunt) and the control device causes the semiconductor switching element to open as soon as this current exceeds a (fixed or variable) predetermined threshold current (function of the semiconductor switching element as an "electronic fuse" for current interruption).

[0014] Furthermore, the power distribution device includes a driver circuit with a driver input for receiving a driver input signal (e.g., a voltage signal) and a driver output for outputting the switching signal corresponding to the driver input signal (e.g., a voltage signal). 202400671

[0015] 3

[0016] Furthermore, the device includes a control unit (e.g. comprising a microcontroller) which is designed to monitor the current flow via the relevant output terminal (e.g. by measuring the current) and to generate the driver input signal taking this current flow into account.

[0017] Compared to a conventional fuse, the semiconductor switching element used as an electronic fuse has the advantage, for example, that it is not destroyed when the fuse blows to interrupt the current, but can be reused after the fault (e.g., short circuit) has been cleared or rectified. In this context, a further advantage is that, for example, when the vehicle is parked or started, the semiconductor switching element can initially be open for safety reasons and only closes after certain safety checks have been completed. Another advantage is that, depending on the vehicle's safety strategy, the semiconductor switching element can also open during current flow through the relevant output terminal for reasons other than an excessively high current flow.

[0018] The control unit is further designed to monitor the correspondence between the driver input signal and the switching signal and, in the event of a mismatch between these two signals, to generate and output an error signal.

[0019] The basic idea of ​​the invention is to consider a mismatch between driver input signal and switching signal as an indicator of a fault event, which consists in the driver circuit not functioning correctly and delivering a faulty driver output signal and / or the semiconductor switching element not functioning correctly and altering the switching signal (driver output signal) applied to its control terminal.

[0020] Here's an example: Assume the semiconductor switching element is a FET, and the switching signal applied to the control terminal (gate) of the FET is a gate voltage, which the driver circuit outputs as its driver output signal corresponding to its driver input signal. As a further example, assume a gate voltage (switching signal) of 5 V to turn the FET on (off), and a gate voltage of 202400671

[0021] 4 out of 15 V is provided for closing (switching on) the FET. As a further example, let us assume that the driver input signal (e.g., generated by a microcontroller) is provided with a voltage of 0 V for opening the FET and with a voltage of 5 V for closing the FET, as summarized in Table 1 below:

[0022] Table 1

[0023] To determine whether the switching signal "corresponds" or "does not correspond" to the driver input signal, respective tolerance ranges can be specified for the switching signal, here gate voltage, as exemplified in Table 2 below:

[0024] Table 2

[0025] Based on a measurement of the actual gate voltage (switching signal) and its evaluation, taking into account the simultaneously specified driver input signal, an error signal can be generated and output (e.g., to a vehicle control unit) if there is a discrepancy between these two signals. The error signal can also represent, for example, an information technology component of a "diagnostic signal" sent to the vehicle control unit permanently or periodically, i.e., the inclusion of an "error code" in such a diagnostic signal. 202400671

[0026] 5

[0027] All numerical values ​​in the above example (Tables 1 and 2) are purely illustrative and may be adapted to the specific application. However, to achieve advantageous fail-safe behavior, it is advisable in the design of the power distribution device to ensure that both a switching signal with a value of zero and a driver input signal with a value of zero result in an open state of the semiconductor switching element.

[0028] In at least one advantageous embodiment according to the first aspect, the control device is further configured to classify a detected fault event (be it a mismatch between the driver input signal and the switching signal, or another event such as a defective driver supply voltage). In the example above (Tables 1 and 2), it can be classified, for example, whether the fault event affects the "off" state or the "on" state of the FET (more generally: semiconductor switching element). Furthermore, in the example above, and more generally, a classification is possible which, in the case of a mismatch, also distinguishes whether the (actual or measured) switching signal is "too large" or "too small" with respect to a predefined tolerance range. In the example above (Tables 1 and 2), for example,The criterion "outside [4 V,5 V]" should be replaced by the criteria "less than 4 V" and "greater than 5 V".

[0029] In at least one advantageous embodiment according to the first aspect, the generation of the error signal depends on the result of such a classification. In this case, the control unit outputs different error signals for differently classified error events.

[0030] In a preferred embodiment of generating and outputting the error signal as a digital signal, the result of the monitoring performed by the control device and thus, in particular, the result of a classification, e.g., as information encoded in the digital signal (e.g., different "error codes" for different error events).

[0031] In at least one advantageous embodiment according to the first aspect, the fault signal, in the case of a digital signal e.g. via a digital communication bus system of the vehicle, is transmitted to another, in particular 202400671

[0032] 6. Transfer to a higher-level control unit, such as a vehicle control unit.

[0033] In at least one advantageous embodiment according to the first aspect, it is provided that the control device is further configured to monitor a driver supply voltage for supplying the driver circuit and to take a result of this monitoring into account when generating the fault signal.

[0034] For example, in the event of a defective driver supply voltage, a further error signal could be provided, generated and output independently of the aforementioned error signal, which could again be, for example, a digital signal and which could again be generated, for example, depending on the result of a classification of the defective driver supply voltage (in this classification, for example, a specifically measured value of the driver supply voltage could be taken into account).

[0035] Preferably, however, it is essentially the same error signal as the aforementioned error signal, in that the control device is designed to generate and output such an error signal if a mismatch is detected between the driver input signal and the switching signal and / or a defective driver supply voltage is detected, both of which affect the functionality of the electronic fuse implemented with the semiconductor switching element.

[0036] In at least one advantageous embodiment according to the first aspect, the fault signal is, in a sense, a specific encoding of a digital "diagnostic signal" that is generated and output from time to time and / or during certain operating situations (e.g., starting up and / or stopping the vehicle or the DC power supply) and / or on demand (e.g., by a vehicle control unit). Such a diagnostic signal can, for example, contain encoded information regarding details (classification) of the fault event, such as different "fault codes" for various predefined classes of fault events. This encoding or the fault codes can also take into account, in particular, a result of monitoring the driver supply voltage, such as a measured value of the driver supply voltage. 202400671

[0037] 7

[0038] Here is an example, which builds on the example above according to Tables 1 and 2: Assuming a driver supply voltage of 20 V is provided for the driver circuit, a respective tolerance range can be specified to determine whether an actual (measured) driver supply voltage is "deficient" or "not deficient", as exemplified by [18 V, 22 V] in the following Table 3:

[0039] Table 3 202400671

[0040] 8

[0041] Based on an additional measurement and evaluation of the actual driver supply voltage, this information can then be encoded into the error signal as part of the information classifying the error event in the event of a defective driver supply voltage. The numerical values ​​in the example above in Table 3 are again purely illustrative and may be different depending on the specific application.

[0042] In at least one advantageous embodiment according to the first aspect, the semiconductor switching element is designed as a transistor, in particular, for example, as a FET (e.g., MOSFET) or, for example, as an IGBT ("Insulated Gate Bipolar Transistor"). This allows the requirements placed on the semiconductor switching element (e.g., voltage and current withstand capability, low switching losses) to be met effectively in most applications.

[0043] In at least one advantageous embodiment according to the first aspect, the switching signal is transmitted via an electrical resistor arranged between the driver output of the driver circuit and the control terminal of the semiconductor switching element. This advantageously provides, for example, protection of the driver circuit in the event of faults where a defect in the semiconductor switching element could cause a potentially damaging voltage to be applied to the driver output via its control terminal (e.g., the gate in the case of a FET). It should be noted that in the applications and situations of particular interest here, a relatively high voltage is applied to the semiconductor switching element, or a relatively large current flows through it.

[0044] In at least one advantageous embodiment according to the first aspect, the power distribution device is designed to transmit electrical power via the input connection that can assume values ​​of more than 10 kW in operation, in particular, for example, more than 30 kW. On the other hand, in most of the applications of particular interest here (in the automotive sector), such a maximum power of, for example, 100 kW is sufficient.

[0045] In at least one advantageous embodiment according to the first aspect, it is provided that the power distribution device for the transmission of electrical power via the 202400671 associated with the semiconductor switching element

[0046] 9

[0047] The output connection is designed to assume values ​​of more than 1 kW in operation, in particular, for example, more than 3 kW. On the other hand, such a maximum power output can be, for example, a maximum of 30 kW.

[0048] In at least one advantageous embodiment according to the first aspect, the power distribution device is designed to connect a DC voltage source at the input terminal, which has a nominal voltage of more than 100 V, in particular more than 400 V. On the other hand, in most cases it is sufficient if this nominal voltage is less than 3 kV, in particular less than 2 kV. For example, an electrical energy storage system installed on board a vehicle, including an electric battery, can be used as the DC voltage source. Alternatively or additionally to a (rechargeable) electric battery, a fuel cell device, for example, can also be provided as the DC voltage source.

[0049] In at least one advantageous embodiment according to the first aspect, it is provided that the control device includes a microcontroller which is configured to generate the driver input signal to be output to the driver input of the driver circuit.

[0050] The driver input signal can, for example, represent a digital voltage signal output by a digital signal output of the microcontroller, with a voltage of 0 V corresponding to a "low" state and 5 V corresponding to a "high" state of this signal (or other predefined voltage values). The driver circuit generates a driver output signal from this at its driver output, which is then fed as the switching signal to the control terminal (e.g., the gate of a FET) of the semiconductor switching element. This switching signal (driver output signal) then corresponds to the driver input signal in that the "low" and "high" states each trigger corresponding states (e.g., different voltage levels) of the switching signal in order to effect the corresponding switching states (open, closed) of the semiconductor switching element (see, for example, the examples in Tables 1 and 2).

[0051] For the decision as to whether the semiconductor switching element (as an electronic fuse) is opened or closed, it may be provided, for example, that the power distribution device includes a current measuring device for measuring a 202400671

[0052] 10

[0053] The current strength of the current flowing through the relevant output terminal (i.e., protected by the semiconductor switching element) is measured, which provides a corresponding measurement signal to the microcontroller, so that in the event of an excessively high current strength, the current flowing through this output terminal can be switched off by opening the semiconductor switching element ('triggering the fuse').

[0054] Such a current measuring device can, for example, include a measuring resistor (shunt) positioned at a suitable point in the distribution line arrangement, along with a measuring amplifier to amplify the measuring voltage across this resistor, which is representative of the current. The (amplified) measuring voltage can then be fed to an analog-to-digital converter (ADC) input of the microcontroller, which then generates a suitable driver input signal (i.e., corresponding to the desired switching signal) depending on the measured voltage.

[0055] Based on such a current measurement, the control unit or the aforementioned microcontroller can trigger the opening of the semiconductor switching element as soon as the measured current exceeds a (fixed or variable) predefined threshold current. A variable threshold current can advantageously be defined, for example, as a function of an "expected current" (e.g., lower for a lower expected current than for a higher expected current). The expected current can be determined, for example, based on information about the current operating state (e.g., on or off) of the electrical load(s) supplied via the relevant output terminal.

[0056] Alternatively or additionally to evaluating the measured current to detect a fault event with excessive current flow by inputting a measured current value (e.g., the aforementioned measuring voltage) to the control unit (e.g., microcontroller), the power distribution device can also include a comparator, in addition to a current measuring device, for comparing the measured current with a (fixed or variable) predefined threshold current. In this case, an output signal from the comparator can be supplied to the control unit (e.g., at a digital signal input of the aforementioned microcontroller), indicating that the threshold current has been exceeded. 202400671

[0057] 11

[0058] The microcontroller can also be used to monitor the correspondence between the driver input signal and the switching signal and / or, in the event of a mismatch between these two signals, to generate and output the error signal.

[0059] For the purpose of such monitoring, it can be provided, for example, that a switching voltage representing the switching signal, or a voltage-split version of this switching voltage, is supplied to the microcontroller at an A / D converter input, so that the microcontroller can monitor the correspondence between the switching voltage (switching signal) and the driver input signal. The driver input signal can be supplied to the microcontroller (if generated outside the microcontroller), or it can already be present within the microcontroller (if generated by the microcontroller).

[0060] For the purpose of generating an error signal, it may be possible, for example, to specify certain tolerance ranges for the corresponding switching signal for each of the possible states of the driver input signal, such as each of the aforementioned "low" and "high" states of a digital signal (see examples of such correspondence in Table 2), or to define other criteria to determine whether the error event is a mismatch between the two signals. In the case of a mismatch, an error signal is generated. This can be transmitted, for example, as a digital signal via the vehicle's digital communication bus system to a higher-level control unit (e.g., the central vehicle control unit). The error signal (e.g., digital signal) can advantageously contain encoded information about the type of error event, such as the result of a corresponding classification.Already described above.

[0061] Monitoring the correspondence between the driver input signal and the switching signal can be implemented as a check performed periodically, e.g., during the operation of the vehicle in question. A particular advantage of the invention is that it allows the functionality of the semiconductor switching element as an "electronic fuse" to be checked, especially when the semiconductor switching element is energized (switched on). Alternatively or additionally, if (at least) one predetermined operating state of the vehicle is present, e.g., during each start-up (and / or 202400671

[0062] 12

[0063] (decommissioning), such a check may be provided for, either with and / or without energizing the semiconductor switching element.

[0064] The fact that, according to the invention, an error signal is generated and output in the event of a mismatch between the driver input signal and the switching signal, does not preclude the possibility that this signal, or more precisely, a signal indicating the mismatch between these two signals, can be generated and output if the two signals do match. In this case, the "error signal" within the meaning of the invention can also be considered a "diagnostic signal" that contains information about the functionality of the power distribution device and / or the (at least one) semiconductor switching element contained therein (e.g., in the form of a digital code). The diagnostic signal can then, for example, provide a higher-level control unit (e.g., a vehicle control unit) with information about the functionality of the power distribution device.

[0065] According to a further aspect of the present invention, a use of a power distribution device of the type described herein for distributing electrical power in a DC power supply of a vehicle for supplying electrical consumers in the vehicle is proposed.

[0066] The electrical consumers supplied by the power distribution device can, in particular, include at least one inverter for supplying power to an AC motor of the vehicle, especially an AC motor intended for propelling the vehicle. The vehicle can therefore be, for example, a battery-electric or hybrid-electric vehicle (BEV or HEV) in which electrical power is distributed via a high-voltage DC power supply.

[0067] Furthermore, the electrical consumers supplied by means of the power distribution device can include, for example, at least one electric heating device of the vehicle (e.g., for heating a vehicle interior or, for example, for heating an electric battery (e.g., traction battery) or an electrical energy storage system containing such a battery).

[0068] The embodiments and special configurations described here for the power distribution device according to the invention can be used individually or in 202400671

[0069] 13. Any combination thereof, analogously also provided as embodiments or special configurations of the use according to the invention, and vice versa. For example, a high-voltage DC power supply with a voltage of more than 100 V or even more than 400 V (e.g., about 800 V to 1000 V) can be provided, from which relatively powerful electrical consumers in the vehicle are supplied, such as, for example, as a "main load," an inverter for supplying power to an AC motor intended for driving the vehicle and arranged for this purpose in a drive train of the vehicle, and as "auxiliary load(s)," for example, at least one further inverter (e.g., for an AC motor for driving a compressor or a pump in the vehicle) and / or, for example, at least one electric heating device.

[0070] For the purposes of the invention, a secondary load can be considered, for example, a load where the maximum expected power flow under operating conditions (e.g., rated power) is at least a factor of 5, and in particular at least a factor of 10, lower than the maximum expected power flow under operating conditions of the most powerful electrical consumer (e.g., electric drive unit). In one embodiment, the (at least one) semiconductor switching element is assigned to an output terminal of the power distribution device, to which (at least) one electrical consumer of the secondary load(s) is connected.

[0071] According to another aspect, a computer program product is comprehensively proposed as program code which, executed on a data processing device (e.g. microcontroller or the like) in a control unit of a power distribution device of the type described here, effects the described monitoring of the correspondence between driver input signal and switching signal (and a corresponding generation and output of an error signal or diagnostic signal).

[0072] The invention is further described below with reference to exemplary embodiments and the accompanying drawing. It schematically illustrates:

[0073] Fig. 1 shows a block diagram of a power distribution device used on board a vehicle according to an exemplary embodiment. 202400671

[0074] 14

[0075] Fig. 1 shows an embodiment of a power distribution device 10 installed on board a battery electric or hybrid electric vehicle (BEV or HEV), by means of which electrical power is distributed in a high-voltage direct current supply (voltage e.g. about 800 V) of the vehicle in order to supply electrical consumers L1 , L2 connected thereto.

[0076] In the example shown, the electrical load L1 is a main load and is, for example, formed by an inverter for supplying power to an electric AC motor intended for propelling the vehicle. The electrical power to be transferred to this main load via output terminal L1 can, under normal operating conditions, assume values ​​of, for example, more than 10 kW, or more than 30 kW, and, on the other hand, can be, for example, a maximum of 100 kW.

[0077] In contrast, the electrical consumer L2 represents an auxiliary load, which is, for example, an electric heating device and / or further inverters (e.g., for electric compressor drives or the like), whereby the electrical power to be transferred to this auxiliary load via the output connection L2 can, in operational terms, assume values ​​of, for example, more than 1 kW or, for example, more than 3 kW, and, on the other hand, a maximum of, for example, 30 kW.

[0078] The power distribution device 10 comprises an input terminal 20 to which an electrical (rechargeable) battery BAT of an electrical energy storage system installed on board the vehicle is connected as a DC voltage source. In this example, the battery BAT supplies the input terminal 20 with a positive DC supply potential DC+ and a negative DC supply potential DC-. The difference between the potentials DC+ and DC- corresponds to the aforementioned high voltage (of approximately 800 V).

[0079] Furthermore, the example shows two output terminals 30-1 , 30-2, to which the electrical consumers L1 (at 30-1 ) and L2 (at 30-2) are connected as shown.

[0080] The power distribution device 10 further comprises a distribution line arrangement 40, which in the example is designed as a two-pole (for the potentials DC+ and DC-), and which is connected on one side to the input terminal 20 and on the other side to the 202400671

[0081] 15

[0082] The supply of consumers L1, L2 is connected or connectable to the output terminals 30-1, 30-2.

[0083] Furthermore, the device comprises a semiconductor switching element 42, in this example a power MOSFET, which is assigned to the output terminal 30-2 and arranged in the distribution line arrangement 40 such that it can be used as an "electronic fuse" to protect the output terminal 30-2. With a switching signal SS (gate voltage) that can be applied to a control terminal G (here gate) of the semiconductor switching element 42 (here FET), the switching element 42 can be selectively opened or closed and thus controlled in such a way that, in the event of an excessively high current flow through the output terminal 30-2, the current flowing through this output terminal 30-2 can be switched off by opening the semiconductor switching element 42 caused by the switching signal SS.

[0084] In this example, the current flowing through output terminal 30-2 is measured using a shunt resistor Rs and a downstream measuring amplifier 60. The measuring amplifier 60 provides an amplifier output signal m2 (here: an analog voltage signal) representative of this current.

[0085] The semiconductor switching element 42 opens as soon as the current exceeds a predefined threshold current. In this example, the threshold current is determined by a reference voltage Vref, which is compared with the measurement voltage (amplifier output signal m2) output by the measuring amplifier 60 using a comparator 70. In contrast to the example shown, a variable threshold current (corresponding to a variable reference voltage Vref in Fig. 1) could also be provided, particularly depending on an "expected current," which can be determined, for example, based on information about the current operating state of the vehicle and / or the electrical load L2.

[0086] The comparator device 70 thus provides a comparator output signal m1 (here: a digital voltage signal) at its output, which indicates whether the current flowing through the output terminal 30-2 exceeds the specified threshold current or not. 202400671

[0087] 16

[0088] Furthermore, the power distribution device 10 comprises a driver circuit 50 with a driver input 52 for receiving a driver input signal TES (here: a digital voltage signal) and a driver output 54 for outputting the switching signal SS corresponding to the driver input signal TES, which is applied to the control terminal G of the semiconductor switching element 42 via an electrical resistor 56. The resistor 56 protects the driver circuit 50 from a potentially destructive overvoltage at the driver output 54, which can occur in the event of a short-circuit defect of the semiconductor switching element 42. A relatively high voltage (high voltage) applied to the switching path of the semiconductor switching element 42 (between source S and drain D) can lead to a significant voltage increase at the control terminal G due to such a defect.

[0089] Furthermore, the device 10 comprises a microcontroller 80, which, in combination with the measuring amplifier 60 and the comparator unit 70, forms a control unit that monitors the current flow via the output terminal 30-2 and, taking this current flow into account, appropriately generates the driver input signal TES. The generation of the driver input signal TES is carried out using (evaluating) the signals m1 and m2 supplied to the microcontroller 80 as shown (alternatively, only one of the two monitoring signals m1 and m2 could also be used for this purpose).

[0090] Unlike a conventional "fuse", the semiconductor switching element 42 can, for example, be initially open when the vehicle is switched off (parked) or when the vehicle is started up according to a safety strategy of the vehicle and can only be closed (switched on) after certain safety checks of a vehicle control unit VCU have been completed, by the vehicle control unit VCU sending a corresponding instruction to the microcontroller 80 via a digital communication bus system of the vehicle (e.g. CAN bus, LIN bus or the like).

[0091] In general, it is preferable to switch on the semiconductor switching element 42 before any voltage is applied (or when a relatively small voltage is applied) to minimize its load. In the example shown, the electrical energy storage system containing the battery BAT includes a switching device (not shown in Fig. 1), e.g., contactors, by means of which the electrical connection of the battery BAT to the power distribution device 10, and thus the voltage supply with the 202400671

[0092] 17

[0093] The DC+ and DC- potentials can be selectively switched on and off. During vehicle commissioning, or, for example, if a problem occurs in the main load (L1) during subsequent operation, the entire system (10, L1, L2) can be switched off using the aforementioned switching device.

[0094] The semiconductor switching element 42 primarily serves to protect the auxiliary load (here: consumer L2) when the entire system is switched on. However, regardless of its overcurrent protection functionality (e.g., in the event of a short circuit in consumer L2), a safety strategy may also provide for the semiconductor switching element 42 to be opened for reasons other than an excessively high current flow, such as to forcibly disconnect consumer L2 for safety reasons.

[0095] A special feature of the power distribution device 10 shown is that it monitors the functionality of the electronic fuse or the semiconductor switching element 42 used for this purpose, in order to be able to take suitable (and adapted) measures to maintain the safety of the vehicle and its occupants in the event of a detected fault event.

[0096] It should be considered, for example, that a semiconductor switching element can develop a "short-circuit defect," often also referred to as a "stuck closed" defect, due to overload and / or degradation over its lifetime. This defect can permanently short-circuit the switching path (e.g., the source-drain channel in a FET) to a greater or lesser degree (independent of the gate voltage) and, furthermore, connect the control terminal (e.g., the gate in a FET) to the switching path with a more or less low resistance. In known power distribution devices, such a defect state is indistinguishable from the switched-on (closed) state of the switching element. This defect is safety-relevant because, in an emergency, the switching element cannot be opened (switched off) to interrupt the current flowing through the relevant output terminal (the "electronic fuse" fails to trip).

[0097] To detect such defects early and generally to monitor their functionality, the power distribution device 10 is designed to monitor the correspondence between the driver input signal TES and the switching signal SS and, in the event of any non-correspondence, 202400671

[0098] 18. To generate an error signal FS between these signals and to output it to the vehicle control unit VCU via the aforementioned digital communication bus system.

[0099] The term "correspondence" is, as explained above, a specific assignment between the two states (e.g. voltage values) of the driver input signal (here: TES) and the respective states (e.g. voltage values ​​or ranges) of the switching signal that are brought about by proper functioning, as provided by the design of the power distribution device 10 or circuit arrangement (component properties etc.).

[0100] In the invention, a mismatch between the driver input signal TES and the switching signal SS is considered an indicator of a fault event. This fault event consists of the driver circuit 50 malfunctioning and therefore delivering a faulty driver output signal (switching signal SS), and / or the semiconductor switching element 42 malfunctioning and thereby altering the switching signal SS (driver output signal) applied to its control terminal G, for example, due to the effect described above in the case of a "short-circuit defect" of the semiconductor switching element 42. For example: Assuming that in the closed (switched-on) state of the semiconductor switching element 42, a voltage of approximately 15 V is present at the gate terminal when the device 10 is functioning correctly, the aforementioned short-circuit defect can cause this gate voltage to drop to, for example, a few volts (e.g., approximately 5 V or less).This defect therefore results in a "non-correspondence" between the signals (here: voltage values) TES and SS, which is detectable with the invention.

[0101] The term "non-correspondence" is to be understood as a significant deviation from the specific assignment between the two states of the driver input signal (TES) and the respective states of the switching signal (SS) resulting from the design of the power distribution device 10 or circuit arrangement.

[0102] For the purpose of the aforementioned monitoring (the correspondence between TES and SS), in the example of Fig. 1, a voltage-divided version of the switching voltage (switching signal) SS is supplied to the microcontroller 80 via a voltage divider 90 at an A / D converter input of the microcontroller 80, 202400671

[0103] 19, which is shown in Fig. 1 as a monitoring signal m3. Based on an evaluation of the supplied monitoring signal m3, taking into account the current driver input signal TES, the microcontroller 80 can thus check the correspondence between the switching signal SS and the driver input signal TES. The driver input signal TES is already present within the microcontroller's domain (since it is generated by the microcontroller 80).

[0104] Regarding the generation of the fault signal FS, it is provided that for each of the two possible states (e.g., "low" and "high") of the driver input signal TES, specific tolerance ranges are defined for the corresponding switching signal SS. These tolerance ranges can be predefined, for example, by a control program running on the microcontroller 80. This allows the system to determine "correspondence" if the switching signal SS lies within the relevant tolerance range and "non-correspondence" if it lies outside the relevant tolerance range. In the event of a non-correspondence, the fault signal FS is generated. This signal is transmitted as a digital signal via the vehicle's communication bus system to the vehicle control unit (VCU).

[0105] The vehicle control unit (VCU) can advantageously evaluate a fault event communicated via the fault or diagnostic signal FS, for example, taking into account the current operating state of the vehicle, and take appropriate measures to maintain safety. Such measures can include, for example, issuing a warning message to the driver (and / or recording the fault in the vehicle control unit's fault memory), as well as initiating a shutdown of the vehicle.

[0106] In the illustrated embodiment, the power distribution device 10 further comprises a voltage divider 100, via which a voltage-divided version of a driver supply voltage VS is supplied to the microcontroller 80 at an A / D converter input of the microcontroller 80. This voltage-divided version is shown in Fig. 1 as a monitoring signal m4. The driver supply voltage VS serves to supply the driver circuit 50. Based on an evaluation of the supplied monitoring signal m4, the microcontroller 80 can thus monitor the driver supply voltage VS and, in the event of a defective (e.g., too low) driver supply voltage VS, detect this condition in the 202400671

[0107] 20

[0108] The detection and diagnosis of fault events must take into account their relevance to the functionality of the "electronic fuse" implemented with the semiconductor switching element 42. In the example shown, however, it is intended that a result of the monitoring of the driver supply voltage VS (e.g., whether defective or not, and / or the value of VS) be included as coded information in the fault signal FS. More generally, the fault signal FS can contain information regarding such details within the framework of classifying a detected fault event. For example, the fault signal FS can contain different "fault codes" for different predefined classes of fault events (where, for example, a value of the driver supply voltage VS determined from the monitoring signal m4 can also be taken into account). Thus, the microcontroller 80 can generate different (i.e., different) fault events for differently classified fault events.Adapted coded) error signals FS are output.

[0109] The fact that an error signal FS is generated and output in the event of a mismatch between the driver input signal TES and the switching signal SS does not preclude the possibility that such a signal, in the sense of a diagnostic signal, can also be generated and output when there is a mismatch between TES and SS. In the latter case, the error signal FS (diagnostic signal) then indicates this mismatch between the two signals.

[0110] In contrast to the representation in Fig. 1 of the power distribution device 10, in which the devices 50, 60, 70, 90, 100 are implemented outside the microcontroller 80, it is also possible to implement one or more of these devices within the microcontroller, for example by means of a so-called peripheral device of a suitable microcontroller or microcontroller module configured accordingly.

[0111] The terms "input connection" and "output connections," as well as the term "electrical load," are to be interpreted within the meaning of the invention such that, at least in certain or typical operating situations, electrical power can enter the power distribution device via the (at least one) input connection, exit the power distribution device via the output connections, and be converted by the electrical loads (e.g., into mechanical power, heat power, etc.). Furthermore, the terms are not to be understood as restrictive with regard to the direction of such power flows. In particular, 202400671

[0112] In the illustrated embodiment, for example, it can be provided that during a recuperation operation of the vehicle, electrical power is generated by the consumer L1 (inverter) (from mechanical power when braking the vehicle, in generator operation of the drive machine), enters the power distribution device via the output terminal 30-1, and exits via the input terminal 20.

[0113] In summary, the invention and the described

[0114] Example of implementation: malfunctions and defects in the area of ​​a power distribution device can be detected or diagnosed at an early stage.

[0115] 202400671

[0116] 22

[0117] Reference symbol list

[0118] 10 Power distribution device 20 Input connection

[0119] DC+, DC- DC supply potentials BAT electric battery 30-1 Output connection (main load) L1 electrical consumer (main load) 30-2 Output connection (auxiliary load) L2 electrical consumer (auxiliary load) 40 Distribution line arrangement 42 Semiconductor switching element G Control connection (gate) 50 Driver circuit VS Driver supply voltage 52 Driver input TES Driver input signal 54 Driver output SS Switching signal (driver output signal) 56 Resistor 60 Current measuring amplifier m2 Amplifier output signal Rs Current measuring resistor 70 Comparator device ml Comparator output signal Vref Reference voltage 80 Microcontroller 90 Voltage divider m3 Monitoring signal 100 Voltage divider m4 Monitoring signal FS Fault signal VCU Vehicle control unit

Claims

202400671 23 Patent claims 1. Power distribution device (10) for distributing electrical power in a DC power supply of a vehicle for supplying electrical consumers (L1, L2) in the vehicle, comprising - an input terminal (20) for connecting a DC voltage source (BAT), - multiple output terminals (30-1 , 30-2) for connecting respective electrical loads (L1 , L2), - a distribution line arrangement (40) which is connected or connectable on the one hand to the input terminal (20) and on the other hand is connected or connectable to the output terminals (30-1 , 30-2), - a semiconductor switching element (42) which is arranged in the distribution line arrangement (40) and which can be controlled by a switching signal (SS) that can be applied to a control terminal (G) of the semiconductor switching element (42), such that in the event of an excessively high current flow via the relevant output terminal (30-2), the current flowing via this output terminal (30-2) can be switched off by opening the semiconductor switching element (42) controlled by the switching signal (SS), - a driver circuit (50) with a driver input (52) for receiving a driver input signal (TES) and a driver output (54) for outputting the switching signal (SS) corresponding to the driver input signal (TES), - a control device (60, 70, 80, 90, 100) configured to monitor the current flow via the relevant output terminal (30-2) and to generate the driver input signal (TES) taking this current flow into account, wherein the control device (60, 70, 80, 90, 100) is further configured to monitor the correspondence between the driver input signal (TES) and the switching signal (SS) and, in the event of a non-correspondence between these two signals, to generate and output an error signal (FS). 202400671 24 2. Power distribution device (10) according to claim 1, wherein the control device (60, 70, 80, 90, 100) is further configured to monitor a driver supply voltage (VS) for supplying the driver circuit (50) and to take into account a result of this monitoring when generating the fault signal (FS).

3. Power distribution device (10) according to one of the preceding claims, wherein the semiconductor switching element (42) is designed as a transistor.

4. Power distribution device (10) according to one of the preceding claims, wherein the switching signal (SS) is transmitted via an electrical resistor (56) which is arranged between the driver output (54) of the driver circuit (50) and the control terminal (G) of the semiconductor switching element (42).

5. Power distribution device (10) according to one of the preceding claims, designed to transmit electrical power via the input connection (20), which can assume values ​​of more than 10 kW during operation.

6. Power distribution device (10) according to one of the preceding claims, designed to transmit electrical power via the output terminal (30-2) associated with the semiconductor switching element (42), which can assume values ​​of more than 1 kW during operation.

7. Power distribution device (10) according to one of the preceding claims, configured for connecting a DC voltage source (BAT) to the input terminal (20) which has a nominal voltage of more than 100 V, in particular more than 400 V.

8. Power distribution device (10) according to one of the preceding claims, wherein the control device (60, 70, 80, 90, 100) comprises a microcontroller (80) which is configured to generate the driver input signal (TES) to be output to the driver input (52) of the driver circuit (50).

9. Use of a power distribution device (10) according to one of claims 1 to 8 for distributing electrical power in a DC power supply of a vehicle for supplying electrical consumers (L1 , L2) in the vehicle. 202400671 25 10. Use according to claim 9, wherein the electrical consumers (L1 , L2) supplied by means of the power distribution device (10) comprise at least one inverter (L1 ) for supplying current to an electric AC machine of the vehicle.

11. Use according to claim 9 or 10, wherein the electrical consumers (L1, L2) supplied by means of the power distribution device (10) comprise at least one electric heating device (L2) of the vehicle.

12. Computer program product comprising a program code that, on a microcontroller (80) in a control unit (60, 70, 80, 90, 100) of a power distribution device (10) according to one of claims 1 to 8, monitors the correspondence between driver input signal (TES) and switching signal (SS).

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