DE102016209354A1 - DEVICE FOR PROTECTING AN ELECTRICAL NETWORK IN A VEHICLE AND A PASSENGER NET AND A VEHICLE - Google Patents

Abstract

The invention relates to an overcurrent protection device for an electrical network, in particular for a high-voltage vehicle electrical system, and such an electric network with an overcurrent protection device, which is a semiconductor switch which is adapted to disconnect a supply line of the network, and a current measuring device which is set up a To detect value of an indicator of the strength of a current flowing through the semiconductor switch load current has. The overcurrent protection device also has a control device which is set up to switch off the semiconductor switch if, in accordance with a predetermined triggering characteristic which determines a triggering criterion for the overcurrent protection device as a function of the value of the indicator, the trigger criterion is met for the value of the indicator detected by the current measuring unit wherein the triggering characteristic can be influenced by means of at least one adjustable parameter in order to adapt the triggering criterion.

Description

The invention relates to a device for protecting an electrical network in a vehicle and an electrical system for a vehicle with such a device and a vehicle with such a vehicle electrical system.

Electrical components in a vehicle, such as electric motors, air conditioning, batteries, etc., are supplied or supplied with electrical energy via electrical lines or emit electrical energy via these lines. In the case of a defect or fault of a single component or a line, there is a change in the flow of current, in particular when short circuits occur, u. U. a hazard to other components, lines, or people, especially for maintenance personnel during repair or maintenance.

In order to protect electrical lines and / or electrical components in the automotive sector, fuses are generally used in which a high current lying above the tripping or rated current of the fuse, for example a short-circuit current, and / or a high energy flux above a tripping threshold of the fuse For example, due to a high current flow over a longer period of time, brings a fusible conductor to melt and thereby the circuit is interrupted.

In this case, the tripping characteristic, which defines a time-current characteristic which represents the turn-off time of an overcurrent protection device, in particular of fuses at different currents, with fuses usually fraught with tolerances, whereby possibly on the one hand minor overcurrents can not be detected and on the other hand Tripping can take place even if a predefined tripping current or energy flow was not exceeded. Moreover, in the case of fuses, the tripping behavior is strongly temperature-dependent and can therefore only be reproduced poorly.

Another disadvantage of fuses is the lack of sensitivity to heavy currents, which flow only for very short periods of time, which in particular can damage electronic semiconductor elements.

It is an object of the invention to provide an improved solution for protecting an electrical vehicle electrical system, in particular against short circuits and overload.

This object is achieved by the device for protecting an electrical network for a vehicle and an electrical system for a vehicle with such a device and a vehicle with such a vehicle electrical system according to the independent claims.

A first aspect of the invention relates to an overcurrent protection device for an electrical network, in particular for a high-voltage vehicle electrical system, which comprises a semiconductor switch which is adapted to disconnect a supply line of the network, and a current measuring device which is set up, a value of an indicator for the To detect strength of a current flowing through the semiconductor switch load current. The overcurrent protection device further comprises a control device configured to turn off the semiconductor switch when, according to a predetermined triggering characteristic defining a triggering criterion, in particular a turn-off time, for the overcurrent protection device depending on the value of the indicator, for the value of the detected value of the current measuring unit Indicator the triggering criterion is met, the triggering characteristic can be influenced by means of at least one adjustable parameter to adjust the triggering criterion.

By a semiconductor switch with an adjustable by at least one parameter tripping characteristic, the separation of a supply line of an electrical network, in particular a high-voltage vehicle electrical system, can be performed flexibly and situation-dependent. The adjustable tripping characteristic is preferably a line-specific and / or component-specific tripping characteristic, ie. H. a selected in view of particular diameter and / or the material of the electrical line (s) and / or the power consumption of one or more components of the electrical network (selected) tripping characteristic. Preferably, the turn-off or trip times of the semiconductor switch can be flexibly chosen, d. H. In particular, it can be set at which overcurrent the overcurrent protection device triggers as quickly or after which time period the semiconductor switch is switched off.

Overall, the invention enables the semiconductor switch to be controlled in a flexible and reliable manner.

The semiconductor switch can have one or more semiconductor switches. In particular, several supply lines can be disconnected with a plurality of semiconductor switches. In particular, an integrated circuit with a plurality of semiconductor switches may be provided, each of the plurality of semiconductor switches preferably being of the type Control device can be controlled so that each one of the several supply lines is disconnected.

In a preferred embodiment, the control device compensates the value of the indicator for the load current flowing through the semiconductor switch with the trigger criterion, so that an overload of the supply line detected and the semiconductor switch is turned off.

In a further preferred embodiment, by determining the value of the indicator for the load current flowing through the semiconductor switch an overload condition, in particular one over a predetermined amount of electric charge flowed or released in the supply line electrical energy loss, the supply line and / or a component could damage the electrical network, determined or detected. The control unit is configured to open or shut off the semiconductor switch in the event of an overload condition, i. H. to separate the supply line, and thereby to control the current flow through the supply line or the semiconductor switch, taking into account or characteristics of the supply line or the electrical components, which are connected by the supply line, so that a damage the supply line and / or connected by the supply line components of the network or a risk to persons, especially maintenance personnel, is avoided.

In a further preferred embodiment, the current measuring device is adapted to determine the value of the indicator for the strength of the load current flowing through the semiconductor switch by, in particular temporal, integration of the indicator for the load current through the semiconductor switch. An integration of the indicator over time takes into account the fact that an overload is characterized by an overcurrent flowing over a certain period of time. Thus, the flow of energy flowing through the semiconductor switch, i. H. the current flowing during a predetermined period of time, are determined particularly easily and reliably. In particular, this can reliably determine whether there is an overload condition or an overload of the supply line and / or several components of the electrical network connected by the supply line, and the semiconductor switch has to be switched off.

Alternatively, the value of the indicator of the magnitude of the load current flowing through the semiconductor switch may be determined by integration of a load voltage which drops, for example, at a resistor in the supply line. A load voltage can be integrated particularly reliably.

In a further preferred embodiment, the current measuring device has at least one analog-digital converter and at least one integration element, wherein the analog-digital converter is configured to convert the load current flowing through the semiconductor switch into a digital signal. The integrator is configured to integrate the digital signal based on a first adjustable parameter. Due to the conversion into a digital signal, integration by the integration element can be carried out particularly easily. In particular, it can be set by means of the first adjustable parameter how fast the semiconductor switch should be opened, ie. H. How quickly the value of the indicator obtained by integration for an overcurrent flowing through the semiconductor switch meets the triggering criterion. Thereby, the triggering of the overcurrent protection device to the supply line and / or connected by the supply line components of the electrical network can be tuned.

In a further preferred embodiment, the integration element is designed as a filter which is adapted to output an output value based on the incoming digital signal, wherein the output value converges to the value of the indicator for the strength of the current flowing through the semiconductor switch.

In a further preferred embodiment, the integration element is designed as an IIR filter with a transfer function that depends on the first adjustable parameter, so that the triggering criterion defined by the triggering characteristic can be adapted independently of the flowing overcurrent based on setting of the first adjustable parameter. In particular, by setting the first parameter, the trip time, i. H. the permissible according to the tripping characteristic duration for which an overcurrent may flow before the semiconductor switch is turned off, be set independently of the actual flowing overcurrent. As a result, the tripping time for many possible overcurrents changes uniformly. For example, the duration of a small flowing overcurrent shortens or lengthens in accordance, for example, by the same factor, with the duration of a large flowing overcurrent.

Preferably, by setting the first adjustable parameter, the trigger criterion can be adjusted without changing the shape of the time-current characteristic, which defines the tripping characteristic. In particular, the time Current characteristic without shape change along the logarithmic time axis to be moved.

In a further preferred embodiment, the current measuring device has at least one exponentiation element, which is designed to amplify the digital signal output by the analog-to-digital converter based on a second adjustable parameter, so that by adjusting the second adjustable parameter by the tripping characteristic Fixed trigger criterion is adjustable depending on the flowing overcurrent. In particular, by setting the second parameter, the trip time, i. H. the allowable in accordance with the tripping characteristic duration for which an overcurrent may flow before the semiconductor switch is turned off, be set depending on the actual flowing overcurrent. In particular, the permissible time duration changes as a function of the flowing overcurrent. As a result, for example, the permissible period of time for which a large overcurrent is allowed to flow can be reduced without significantly changing the permissible period of time for which a small overcurrent may flow. Thereby, the adaptation of the overcurrent protection device to the supply line or to components which are connected by the supply line, particularly flexible.

Preferably, by setting the second adjustable parameter, the triggering criterion is adjustable by adjusting the tripping characteristic, i. H. In particular, the shape of the time-current characteristic, which defines the tripping characteristic, is changed. In particular, the slope of the time-current characteristic thereby changes at least partially, in particular not uniformly.

In a further preferred embodiment, the value of the indicator of the strength of the load current flowing through the semiconductor switch, determined by integration of the load current, is adjusted in a comparator with a predetermined threshold value, the control device being adapted to switch off the semiconductor switch, if the value of the indicator Threshold reached or exceeded. As a result, it can be ensured in a particularly simple manner that the semiconductor switch is reliably switched off at a value of the indicator corresponding to the triggering criterion. Preferably, the predetermined threshold value is selected based on the triggering criterion.

In a further preferred embodiment, the control device is set up to reset the semiconductor switch after a shutdown if the value of the indicator no longer reaches or falls below the threshold value. In particular, the semiconductor switch can be turned on again from the time, d. H. the electrically conductive connection between at least two components of the electrical network via the supply line to be restored, to which no overload condition is present, d. H. the supply line no longer causes overcurrent. As a result, the supply line of the electrical network can be charged again, d. H. Power without having to replace a physical component of the overcurrent protection device.

In a further preferred embodiment, the control device has at least one interface and is configured to output a switch-off signal via the at least one interface when the semiconductor switch has been switched off. As a result, in particular by a control unit of the vehicle and / or maintenance personnel, a discharge of the electrical network, in particular of the high-voltage vehicle electrical system, can be initiated, so that the semiconductor switch is turned on in a no-load condition. Further preferably, the control device is also configured to output an activation signal via the at least one interface after switching on the semiconductor switch, so that a startup, d. H. Commissioning, the electrical network can be initiated.

In a further preferred embodiment, the control device is set up to reset the semiconductor switch when it receives a reset signal, which in particular can be sent by a control unit and / or triggered by a user, in particular by maintenance personnel. Thereby, the semiconductor switch can be reset when the user, in particular the maintenance staff, has fixed the cause of the overload or the overcurrent and the control device signals by inputting or triggering the reset signal that the supply line or connected by the supply line components of the electrical Network can be reliably used again.

In a further preferred embodiment, the semiconductor switch is designed as a bipolar transistor with an integrated gate electrode (insulated gate bipolar transistor, IGBT). As a result, the current-voltage characteristic, in particular the current flow through the IGBT, can be changed in a particularly simple manner by applying a control voltage, in particular between the gate electrode (hereinafter gate) and an emitter electrode (hereinafter emitter) of the IGBT.

Particularly advantageous is the use of a short-circuit-proof IGBT which limits the saturation current flowing through the IGBT, ie a current-voltage characteristic in the active working range at high voltages between the collector electrode (hereinafter: collector) and the emitter, which is substantially horizontal or only slightly rising, that has only a slight slope.

In a further preferred embodiment, the current measuring device detects the value of the indicator for the strength of the load current flowing through the semiconductor switch on the basis of a load voltage dropping across a load resistor. Preferably, the load resistor is designed as a low-resistance resistor (shunt), so that the falling load voltage is proportional to the load current. The load resistor preferably has an ohmic resistance of essentially 1 mΩ. The dropping load voltage can be easily processed, in particular potentiate and integrate, and in particular compare with a predetermined voltage value, so that the shutdown of the semiconductor switch can be controlled by means of the adjustment.

In a further preferred embodiment, the IGBT has a current mirror emitter which is set up to divert a partial current dependent on this load current from a load current flowing through the semiconductor switch, wherein the current measuring device is set to receive a value of an indicator of the intensity of the partial current to detect the load current flowing through the semiconductor switch. In particular, the branched partial flow and the load flow are in a fixed ratio, so that by determining the strength of the partial flow and the strength of the load current is determined. Thereby, a power loss occurring in detecting the value of the indicator can be reduced or even substantially avoided, whereby the efficiency of the overcurrent protection device is improved.

In a further preferred embodiment, a voltage measuring device is provided, which is set up to detect a value of a further indicator for the saturation of the semiconductor switch and to switch off the semiconductor switch if the value of the further indicator indicates at least partial desaturation of the semiconductor switch. The saturation of the semiconductor switch, which is dependent on the number of available free charge carriers, which are available for a current transport through the semiconductor switch, decreases when the current through the semiconductor switch increases sharply, in particular by a short-circuit current.

In a further preferred embodiment, the voltage measuring device is similar to the voltage dropping across the semiconductor switch during operation of the semiconductor switch, in particular a voltage between a collector electrode (hereinafter: collector) and the emitter of the IGBT or a voltage based on the voltage drop during operation of the semiconductor switch, with a predetermined desaturation voltage and turns off the semiconductor switch when the voltage dropping in operation at the semiconductor switch voltage or voltage based on the falling voltage of the semiconductor switch is greater than the predetermined desaturation voltage.

In a further preferred embodiment, the current measuring device and / or the control device and / or the voltage measuring device is formed on an application-specific integrated circuit (ASIC). In particular, the current measuring device and / or control device and / or the voltage measuring device can be formed on the ASIC. This makes it possible to realize the overcurrent protection device with a few circuit parts or physical components (ICs). Further preferably, the ASIC has at least one interface and is adapted to output the circuit state of the semiconductor switch and / or the determined value of the indicator for the current flowing through the semiconductor switch current via this interface. Alternatively or additionally, the tripping characteristic set based on the at least one parameter and / or the voltage dropping on the semiconductor switch during operation of the semiconductor switch, in particular a voltage based on the voltage drop across the semiconductor switch during operation of the semiconductor switch, can be output via the interface. The interface is preferably connected to a data bus of the vehicle, in particular a LIN bus, so that the determined value of the indicator and / or the set tripping characteristic and / or the falling voltage, in particular from another data bus subscriber, in particular a control unit, can continue to be used ,

In a further advantageous embodiment, the overcurrent protection device has a driver for controlling the semiconductor switch and a voltage supply of the driver, wherein the control device is adapted to the driver according to the value determined by the current measuring device of the indicator of the strength of the load current flowing through the semiconductor switch and / / or in accordance with the value of the further saturable indicator of the semiconductor switch determined by the voltage measuring device so that the semiconductor switch is turned off when, according to the predetermined triggering characteristic for the value of the indicator detected by the current measuring unit, the triggering criterion is met, and / or if Value of the other indicator indicates an at least partially desaturation of the semiconductor switch. The control device is also to set up to control the voltage supply of the driver so that the occurrence of desaturation is affected. In particular, by controlling the voltage supply of the driver, the maximum permissible current can be adjusted as a function of at least one property of the semiconductor switch or the supply line separable by the semiconductor switch or the components of the electrical network connected by the supply line. Such a property may preferably be the material or a property of the material, in particular the conductivity, of the semiconductor switch or of the supply line and / or the dimensions, in particular the thickness or the diameter of the semiconductor switch or the supply line and / or the power consumption at least be one of the components connected by the supply line. By controlling the power supply of the driver, the desaturation occurs upon occurrence of a short circuit, ie flow of a short-circuit current, depending on the setting advantageously earlier or later.

In a further preferred embodiment, the current measuring device is set up to transmit or transmit a control signal to the driver so that the driver switches off the semiconductor switch. The semiconductor switch can thus be switched off faster than via the control device. The current measuring device preferably generates the control signal when the voltage dropping during operation at the semiconductor switch or the voltage based on the falling voltage of the semiconductor switch is greater than the predetermined desaturation voltage. This ensures that, in particular in the case of a short circuit, the supply line and / or a component of the electrical network connected or connected via the supply line is not damaged and / or there is no danger to persons, in particular maintenance personnel.

In a further preferred embodiment, the overcurrent protection device has at least one temperature measuring device which is set up to generate a temperature signal as a function of the temperature of the semiconductor switch. The control device is preferably set up to determine or detect the temperature of the semiconductor switch, in particular during operation of the semiconductor switch, on the basis of the temperature signal of the temperature measuring device. This allows the temperature of the semiconductor switch in the opening, d. H. switching off, the semiconductor switch, to be involved.

In particular, the opening of the semiconductor switch can be carried out as a function of the temperature of the semiconductor switch. A second aspect of the invention relates to an electrical network, in particular a high-voltage vehicle electrical system. It has at least one network component, which is set up to consume and / or generate electrical energy, and at least one energy store, which is configured to receive, store and deliver electrical energy from the vehicle electrical system. The electrical network also has at least one supply line, which electrically conductively connects the at least one network component to the at least one energy store, and at least one overcurrent protection device according to the first aspect of the invention, in particular according to one of the previously described related embodiments, which is adapted to to separate electrically conductive connection between the at least one network component and the at least one energy storage.

A third aspect of the invention relates to a vehicle, in particular a motor vehicle, with at least one electrical network according to the second aspect of the invention.

The features and advantages described in relation to the first aspect of the invention and its advantageous embodiment also apply to the second and third aspects of the invention and its advantageous embodiment and vice versa.

Other features, advantages and applications of the invention will become apparent from the following description taken in conjunction with the figures. Show it:

1 a first exemplary embodiment of an overcurrent protection device;

2 a second exemplary embodiment of an overcurrent protection device;

3 an exemplary embodiment of a current measuring device; and

4 a schematic representation of a tripping characteristic.

1 shows a first exemplary embodiment of an overcurrent protection device 1 for an electrical network, in particular for a high-voltage vehicle electrical system. Here is a semiconductor switch 10 in a supply line 2 between two connection points 3 . 3 ' arranged. The semiconductor switch 10 is designed to provide power flow through the supply line 2 to allow or prevent, in particular by disconnecting the supply line 2 ie interrupting the flow of current through the supply line 2 ,

The semiconductor switch 10 is as a bipolar transistor with integrated gate electrode 11 Insulated gate bipolar transistor (IGBT) is formed. The supply line 2 is over the first connection point 3 with the collector 12 of the IGBT and the second connection point 3 ' with the emitter 13 connected to the IGBT. About the between the gate 11 and the emitter 13 adjacent gate-emitter voltage U _GE can be according to a characteristic of the IGBT, the collector current I _C influence. In particular, by suitable choice of the gate-emitter voltage U _GE, a very small saturation voltage U _CE (collector-emitter voltage) of about 1-3 V can be achieved, so that forward losses compared to forward losses, that in the case of metal oxide semiconductors Field effect transistors occur negligible.

The semiconductor switch 10 includes in the example shown one between collector 12 and emitter 13 switched zener diode 14 to the maximum voltage when switching off the semiconductor switch 10 limit. In particular, the Zener diode 14 set up in the supply line 2 existing electrical energy when opening or turning off the semiconductor switch 10 dissipate. This allows the semiconductor switch 10 be reliably protected against destruction.

The semiconductor switch 10 In the example shown, this also includes a Zener diode 14 ' between collector 12 and gate 11 so that in the supply line 2 existing electrical energy when opening or turning off the semiconductor switch 10 is dissipated essentially in the semiconductor switch.

In another embodiment (not shown), it is also possible to use only one of the two Zener diodes 14 . 14 ' to be provided, in particular depending on the requirement and application of the overcurrent protection device 1 in the (respective) electrical network. With elimination of the zener diode 14 between collector 12 and emitter 13 At this point, another diode is provided, which allows a current flow in opposite, ie reverse, direction to the semiconductor switch 10 to protect against destruction at such a current flow.

The semiconductor switch 10 has several derivatives, in particular inputs and / or outputs, on which he with a control device 20 connected is. The control device 20 has terminals D, G, CS, E, which are connected to the leads and adapted to output signals and in particular voltages and / or currents, and / or to receive or transmit. In some embodiments, at least a portion of these signals provide information about the state, in particular about the circuit state, of the semiconductor switch 10 , A, in particular other, part of these signals controls the semiconductor switch 10 , ie switches the semiconductor switch 10 from a conductive, ie the connection points 3 . 3 ' connecting, in a blocking, ie separating state, or vice versa, or determines or regulates the flowing collector current I _C.

At terminal D, the collector potential is applied, based on which the control device 20 can determine the collector-emitter voltage U _CE .

Via terminal G, the control device 20 Control signals to the semiconductor switch 10 , especially the gate 13 , output or the semiconductor switch 20 control, in particular turn off, in particular, via a voltage at the terminal G, the gate-emitter voltage U _{GE can be} adjusted.

About port CS is the control device 20 one from the current flow through the semiconductor switch 10 diverted current flow, ie a partial current, available, which in a fixed relationship to the current flow through the semiconductor switch 10 stands.

At terminal E, the emitter potential is applied, which can be used by the control device for determining the collector-emitter voltage U _CE and the gate-emitter voltage U _GE . In particular, the potential at the terminal E as the reference potential of the control device 20 be used.

The control device 20 In the illustrated example, it is designed as a circuit on a semiconductor chip, in particular as an application-specific integrated circuit (ASIC). Other components of the overcurrent protection device 1 can therefore easily into the control device 20 can be integrated, ie in particular as part of the control device 20 be educated. The control device 20 has, for example, a current measuring device 21 and a tension measuring device 22 on.

The current measuring device 21 is adapted to a load voltage at the semiconductor switch 10 a value of an indicator for one through the semiconductor switch 10 flowing current, in particular an energy flow, ie to determine a current flowed over a predetermined period of time to determine. The load voltage preferably depends on the load current which flows through the supply line 2 and the semiconductor switch 10 flows. To do this measures the current measuring device 21 a signal, in particular a current at the terminal CS.

The tension measuring device 22 is arranged to be based on a in the operation of the semiconductor switch 10 at the semiconductor switch 10 declining voltage, especially the Saturation voltage U _CE or on a voltage based on the saturation voltage U _CE , another value of an indicator for the saturation of the semiconductor switch 10 capture. To do this measures the voltage measuring device 22 a signal, in particular a potential at the terminal D, ie at the collector 12 , in particular with reference to the potential at port E.

The control device 20 is adapted to the semiconductor switch 10 based on the determined value of the indicator for the semiconductor switch 10 To control flow, and / or the determined further value of the indicator for the saturation state, ie to close, keep closed and / or open, ie the connection points 3 . 3 ' the electric wire 2 conductively connect, hold connected and / or disconnect by a signal, in particular a voltage / or a current, via the terminal G to the semiconductor switch 10 is issued. In the present embodiment, the control device comprises 20 a driver unit 23 , which is adapted to output the corresponding signal or the corresponding signals via the terminal G or the semiconductor switch 10 via the connection G with a corresponding voltage and / or a corresponding current to control.

In the illustrated embodiment, a driver power supply 24 the driver unit 23 parameterizable, whereby the maximum through the semiconductor switch 10 flowing current, in particular the maximum permissible collector current I _C , easily set, ie can be specified. Preferably, that of the drive voltage supply 24 Provided supply voltage of the driver unit 23 essentially 10 to 18 volts, preferably 12 to 16 volts. In a preferred embodiment of the overcurrent protection device 1 is the drive voltage supply 24 formed by a charge pump.

To the recorded at the input CS, analog signal, in particular the recorded load voltage and / or load current, in the current measuring device 21 The control device can be processed particularly simply and efficiently 20 a first analog-to-digital converter 25 , which is adapted to convert the analog signal into a digital signal. The analog-to-digital converter 25 For example, it can be designed as a sigma-delta modulator with a downstream low-pass filter, in particular a Sinc ³ low-pass filter. The sigma-delta modulator converts the analog signal, in particular the load voltage, into a modulated pulse train, from which the low-pass filter, in particular the Sinc ³ low-pass filter, filters out the digital signal and makes it available for further use.

In another embodiment, not shown, the first analog-to-digital converter 25 also part of the current measuring device 21 be.

In the illustrated embodiment, the semiconductor switch formed as an IGBT 10 a current mirror emitter 15 on, which provides an outgoing load current at the input CS. An analog load voltage supplied by the analog-to-digital converter 25 , in particular of the sigma-delta modulator with a downstream low-pass filter, in particular the Sinc ³ low-pass filter is converted into a digital signal, can from the load current through an upstream load, in particular against a predetermined potential, in particular against the emitter potential At port E, switched resistance can be generated. Alternatively, the analog-to-digital converter 25 by means of a charge pump, in particular by means of a capacitor which is discharged at a defined voltage, for example 0.2 volts, with a frequency to be formed. In this case, this frequency is a measure of the current incoming at the terminal CS and can be easily processed digitally, in particular after filtering.

The signal taken at the connection CS and digitized can be connected to a further connection, in particular an interface S of the control device 20 , other components of the vehicle, such as control units, via a data bus, in particular a LIN bus, are made available.

Similarly, also behind port D is a second analog-to-digital converter 25 ' as part of the control device 20 provided, which in operation at the semiconductor switch 10 decreasing voltage, in particular the collector-emitter voltage or saturation voltage U _CE , converted into a digital signal, which from the voltage measuring device 22 for determining the value of the indicator for the saturation of the semiconductor switch 10 is used.

In another, not shown embodiment, the second analog-to-digital converter 25 ' also part of the tension measuring device 22 be.

The signal taken off at the connection D and digitized can be connected to a further connection, in particular an interface S 'of the control device 20 , other components of the vehicle, such as control units, via a data bus, in particular a LIN bus, are made available.

The data provided by the interface S, S 'data or signals allow For example, a condition monitoring of the semiconductor switch 10 by a control device of the vehicle which is in communication with at least one component connected to the supply line 2 connected. In particular, it is possible, the plausibility of the state of the semiconductor switch 10 by checking against data provided by the at least one component. In particular, during operation on the semiconductor switch 10 decreasing voltage or saturation voltage U _CE and / or by the semiconductor switch 10 flowing current or the collector current I _{C are} checked. This may cause a malfunction of the semiconductor switch 10 can be easily detected and optionally reported to the driver of the vehicle and / or stored in a fault memory.

The overcurrent protection device 1 may also comprise a clamping device (not shown), which is adapted to a parasitic, ie a by a displacement current between the collector 12 and gate 11 triggered, in particular unintentional or uncontrolled, switching on the semiconductor switch 10 after a controlled shutdown of the semiconductor switch 10 , ie a successful separation of the supply line 2 , to avoid. It must be ensured that the gate-emitter voltage U _GE always remains smaller than the threshold voltage of the semiconductor _switch in the off state 10 in which a current flow I _C occurs. Preferably, a metal-oxide-semiconductor field effect transistor (MOSFET) may be used between gate 11 and emitter 13 be provided, wherein the drain electrode of the MOSFET before an ohmic resistance with the electrical supply line of the gate 11 , the gate electrode of the MOSFET behind the resistor with the electrical supply of the gate 11 , and the source of the MOSFET with the emitter 13 connected is.

2 shows a second exemplary embodiment of an overcurrent protection device 1 , wherein the overcurrent protection device 1 , in particular the semiconductor switch 10 , a temperature measuring device, preferably comprising one or more diodes ( 16 ), for temperature measurement of the semiconductor switch 10 having, via one or more terminals T with the control device 20 connected is. Further preferably, the control device 20 adapted to the measured temperature of the semiconductor switch 10 in the control of the semiconductor switch 10 , ie when opening or when switching off, to include. In particular, based on the temperature measurement, the triggering criterion can be selected or adjusted. Alternatively or additionally, the current measuring device 21 and / or the voltage measuring device 22 the measured temperature in determining the value of the indicator for the by the semiconductor switch 10 flowing current and / or in the determination of the further value of the indicator for the saturation of the semiconductor switch 10 considered, ie used. This will control the semiconductor switch 10 , or the triggering of the overcurrent protection device 1 , especially reliable.

Further preferably, by the temperature of the semiconductor switch measured by the temperature measuring device 10 the determined value of the indicator for the by the semiconductor switch 10 flowing current and / or the determined further value of the indicator for the saturation state of the semiconductor switch 10 be checked or corrected.

Alternatively, the temperature measurement of the control device 20 without the temperature measuring device, in particular without the one or more diodes ( 16 ), directly on the basis of at least one of at least one of the terminals D, G, CS, E recorded signal to be performed. Here, a temperature model is in a memory of the control device 20 provided, by means of which the temperature of the semiconductor switch 10 is determined based on the at least one signal.

In the in 2 shown second exemplary embodiment is further the interconnection of the terminal D with respect to the interconnection in 1 changed. Here is at least one of the diodes 14 . 14 ' provided as a diode with two anode connections. This can be compared to the embodiment in 1 advantageous components can be saved, which increases the structure of the overcurrent protection device 1 simplified.

In addition, the control device has 20 via a further interface S ", via which preferably the circuit state of the semiconductor switch 10 is output, ie whether the semiconductor switch 10 the connection points 3 . 3 ' conductively connects or the supply line 2 separates. Preferably, the temperature determined by at least one of the interfaces S, S ', S "can also be determined by the semiconductor switch 10 be issued.

The other features correspond to those in 1 shown and discussed accordingly features.

3 shows an exemplary embodiment of the current measuring device 21 , Via a supply line 30 is the reconstructed or digitized, at the terminal CS (see 1 ), signal provided. In particular, voltage differences in different overcurrents differ only slightly from each other, the digital signal is in a potentiating 31 with an exponent, especially with the second adjustable parameter p, increased. To the circuit complexity for the realization of the potentiator 31 to keep low, in particular in order to save computing capacity or to keep the logic costs low, the exponentiation resorted to a lookup table in a memory unit (not shown) of the current measuring device 21 or the overcurrent protection device 1 is stored. The lookup table contains the potentiated values of all relevant, incoming digital signal values. The values of the look-up table are preferred in the development of the overcurrent protection device 1 or the control device 20 calculated or determined or determined by trial or simulation. To save further storage space, the bit depth of the digital signal before exponentiation may be reduced, for example to 9 bits, resulting in digital signal values suitable for use in the current measuring device 21 are sufficiently accurate.

mit τ = 2^kausgebildet sein, wobei F(z) aus einer z-Transformation vom Zeitbereich in den Bildbereich hervorgeht. Die Übertragungsfunktion kann daher durch Einstellen eines ersten einstellbaren Parameters k angepasst werden. Insbesondere kann durch Variation des ersten einstellbaren Parameters k die Sprungantwort des IIR-Filters, d. h. der nach einer gewissen (Integrations-)Zeit ermittelte Wert des Indikators für den durch den Halbleiterschalter 10 fließenden Strom, verändert und somit die Auslösecharakteristik der Überstromschutzvorrichtung 1 angepasst werden. Insbesondere sinkt die Sprungantwort des IIR-Filters bei wachsendem Parameter k, so dass der Halbleiterschalter 10 bei einem festen Überstrom und kleinem Parameter k schneller bzw. bei großen Parameter k langsamer abgeschaltet wird, d. h. bei kleinem Parameter k wird ein kleinerer Energiefluss, und bei größerem Parameter k wird ein größerer Energiefluss durch den Halbleiterschalter 10 zugelassen.After the exponentiation with the second adjustable parameter p, the digital signal is converted into an integrator by means of a digital filter 32 integrated. In this case, the filter, for example, as an IIR filter with a transfer function

with τ = 2 ^k , F (z) resulting from a z transformation from the time domain to the image domain. The transfer function can therefore be adjusted by setting a first adjustable parameter k. In particular, by varying the first adjustable parameter k, the step response of the IIR filter, ie the value of the indicator determined by the semiconductor switch after a certain (integration) time, can be determined 10 flowing current, and thus changes the tripping characteristic of the overcurrent protection device 1 be adjusted. In particular, the step response of the IIR filter decreases with increasing parameter k, so that the semiconductor switch 10 k is turned off more slowly at a fixed overcurrent and small parameter k, or slower at large parameters k, ie, with a smaller parameter k, a smaller energy flow, and with a larger parameter k, a larger energy flow through the semiconductor switch 10 authorized.

The filtered or integrated digital signal value, ie the determined value of the indicator for the by the semiconductor switch 10 flowing electricity coming from the integrator 32 is output, is in a comparator 33 with one at the comparator entrance 34 predetermined value, in particular a predetermined digital value, adjusted, and a corresponding signal on the derivative 35 output. In particular, a control signal is sent to the driver 23 (please refer 1 ), so that the semiconductor switch 10 opened or shadowed, ie the supply line 2 disconnected, when the integrated digital signal value, ie the value determined by the indicator for the semiconductor switch 10 flowing current, greater than the predetermined value.

Preferably, the at the comparator input 34 predetermined value adjusted based on the first adjustable parameter p and / or the second adjustable parameter p, in particular by a predetermined function f (p, k). This allows the at the comparator input 34 predetermined value the triggering criterion for switching off the semiconductor switch 10 as the third adjustable parameter influence or determine.

4 shows a schematic representation of a tripping characteristic 100 the overcurrent protection device 1 , In this case, the logarithm of the time t, for which an overcurrent I through the semiconductor switch 10 allowed to flow, ie the turn-off, against the normalized to a nominal current I _N overcurrent I applied. The nominal current I _N corresponds to the normally flowing, ie approved, current flow through the semiconductor switch 10 , For example, the maximum permissible collector current I _C. Therefore, for I = I _N, the turn-off time of the overcurrent protection device 1 infinite or not defined, so that the nominal current I _N can be arbitrarily long.

For low overcurrents I, the turn-off time t becomes very large. For large overcurrents I on the other hand, the turn-off time t is rapidly smaller. This clarifies the tripping characteristic 100 through a first area 101 , which drops very steeply as the overcurrent I increases. The tripping characteristic 100 goes in a second area 102 over, by the waste is less pronounced.

By a variation of the first adjustable parameter k, ie the setting of the transfer function of the integration member 32 used filter, the overall tripping characteristic 100 , or the curve which the tripping characteristic 100 reflects, adjusted, in particular, be shifted along the time axis. This is through the dotted line 103 and the double-headed arrow next to the reference symbol k. In particular, by increasing the parameter k, the turn-off time t of the overcurrent protection device 1 be increased by the tripping characteristic 100 is moved upwards. Accordingly, by reducing the parameter k, the turn-off time t of the overcurrent protection device 1 be reduced by the tripping characteristic 100 is moved down. In particular, this increase or decrease in the turn-off time t relates to all overcurrents I, ie both weak and small as well as strong or large overcurrents I.

By a variation of the second adjustable parameter p, ie the exponent used in the potentiator 31 (please refer 2 ), the second area 102 the tripping characteristic 100 adjusted, in particular the slope in the second area 102 be increased or decreased. This is through the dashed line 102 ' and the curved double-headed arrow indicated by the reference numeral p. In particular, by increasing the parameter p, the (negative) slope in the second region 102 be increased, so that the tripping time t for large overcurrents I is greatly reduced, while it is only slightly reduced for moderate overcurrents I and substantially not at all reduced for small overcurrents I. In particular, the strength of the adjustment of the tripping characteristic depends 100 from the flowing overcurrent I by the parameter p.

LIST OF REFERENCE NUMBERS

1

Overcurrent protection device

2

supply line

3, 3 '

connection Punk

10

Semiconductor switches

11

Gate electrode

12

Collector electrode

13

Emitter electrode

14, 14 '

Zener diode

15

Current mirror emitter

16

Diode for temperature measurement

20

control device

21

Current measuring device

22

Voltage measuring device

23

driver

24

power supply

25, 25 '

Analog to digital converter

30

supply

31

Potenzierglied

32

integrator

33

comparator

34

comparator

35

derivation

100

tripping characteristic

101

first area

102

second area

102 '

moved second area

103

shifted tripping characteristic

S, S ', S' '

interface

k

first adjustable parameter

p

second adjustable parameter

Claims (15)

Overcurrent protection device ( 1 ) for an electrical network, in particular for a high-voltage vehicle electrical system, comprising: a semiconductor switch ( 10 ), which is set up, a supply line ( 2 ) of the network; a current measuring device ( 21 ), which is adapted to provide a value of an indicator of the strength of a through the semiconductor switch ( 10 ) to detect flowing load current; and a control device ( 20 ), which is adapted to the semiconductor switch ( 10 ) when, according to a predetermined triggering characteristic ( 100 ), which is a triggering criterion for the overcurrent protection device ( 1 ) depending on the value of the indicator for which the current measuring unit ( 21 ) value of the indicator meets the trigger criterion; the triggering characteristic ( 100 ) can be influenced by means of at least one adjustable parameter (p, k) in order to adapt the triggering criterion. Overcurrent protection device ( 1 ) according to claim 1, wherein the current measuring device ( 21 ) is adapted to adjust the value of the strength indicator by the semiconductor switch ( 10 ) flowing load current through, in particular temporal, integration of the indicator for the by the semiconductor switch ( 10 ) to determine the flowing load current. Overcurrent protection device ( 1 ) according to claim 2, wherein the current measuring device ( 21 ) at least one analog-to-digital converter ( 25 ) and at least one integrator ( 32 ), and the analog-to-digital converter ( 25 ) is arranged to pass through the semiconductor switch ( 10 ) convert the flowing load current into a digital signal, and the integrator ( 32 ) is arranged to integrate the digital signal based on a first adjustable parameter (k). Overcurrent protection device ( 1 ) according to claim 3, wherein the integration member ( 32 ) is designed as an IIR filter with a transfer function that depends on the first adjustable parameter (k), so that based on setting of the first adjustable parameter (k) the tripping criterion determined by the tripping characteristic is adjusted independently of the flowing overcurrent. Overcurrent protection device ( 1 ) according to one of claims 2 to 4, wherein the current measuring device ( 21 ) at least one potentiating member ( 31 ), which is adapted to that of the analog-to-digital converter ( 25 ) to increase the output digital signal based on a second adjustable parameter (p), so that on the basis of adjusting the second adjustable parameter (p), the tripping characteristic determined by the tripping characteristic is adjusted depending on the flowing overcurrent. Overcurrent protection device ( 1 ) according to claim 4, wherein the by integration of the load current determined value of the indicator of the strength of the semiconductor switch ( 10 ) flowing load current in a comparator ( 33 ) is adjusted with a predetermined threshold value, and the control device ( 20 ) is adapted to the semiconductor switch ( 10 ) when the value of the indicator reaches or exceeds the threshold. Overcurrent protection device ( 1 ) according to claim 6, wherein the control device ( 20 ) is adapted to the semiconductor switch ( 10 ) after a shutdown if the value of the indicator no longer reaches or exceeds the threshold. Overcurrent protection device ( 1 ) according to one of the preceding claims, wherein the semiconductor switch ( 10 ) as a bipolar transistor with integrated gate electrode ( 11 ), IGBT, is formed. Overcurrent protection device ( 1 ) according to one of the preceding claims, wherein the current measuring device ( 21 ) the value of the indicator of the strength of the semiconductor switch ( 10 ) is detected by a load voltage dropping across a load resistor. Overcurrent protection device ( 1 ) according to claim 8, wherein: the IGBT comprises a current mirror emitter ( 15 ), which is adapted from one through the semiconductor switch ( 10 ) flowing load current to divert a dependent of this load current partial flow; and the current measuring device ( 21 ) is arranged to detect from the substream a value of an indicator of the magnitude of the load current. Overcurrent protection device ( 1 ) according to one of the preceding claims, comprising a voltage measuring device ( 22 ), which is set to a value of a further indicator for the saturation of the semiconductor switch ( 10 ) and the semiconductor switch ( 10 ), if the value of the further indicator at least partially desaturates the semiconductor switch ( 10 ). Overcurrent protection device ( 1 ) according to one of the preceding claims, wherein the current measuring device ( 21 ) and / or the control device ( 20 ) and / or the voltage measuring device ( 22 ) is formed on an application-specific integrated circuit, ASIC. Overcurrent protection device ( 1 ) according to claim 12, further comprising a driver ( 23 ) for controlling the semiconductor switch ( 10 ) and a power supply ( 24 ) of the driver ( 23 ); the control device ( 20 ) is set up the driver ( 23 ) according to the current measuring device ( 21 ) value of the indicator of the strength of the semiconductor switch ( 10 ) flowing load current and / or according to the by the voltage measuring device ( 22 ) value of the further indicator for the saturation of the semiconductor switch ( 10 ), so that the semiconductor switch ( 10 ) is switched off when, according to the predetermined triggering characteristic ( 100 ) for which the current measurement unit ( 21 ) value of the indicator, the trigger criterion is met, and / or if the value of the further indicator at least partially desaturation of the semiconductor switch ( 10 ), and wherein the control device is adapted to supply the power supply ( 24 ) of the driver ( 23 ) so that the onset of desaturation of the semiconductor switch ( 10 ) being affected. Electric network, in particular high-voltage vehicle electrical system, comprising: at least one network component that is configured to consume and / or generate electrical energy; at least one energy storage, which is adapted to receive electrical energy from the electrical system, store, and deliver; at least one supply line ( 2 ), which connects the at least one network component with the at least one energy storage electrically conductive; and at least one overcurrent protection device ( 1 ) according to one of the preceding claims, which is adapted to the electrically conductive connection ( 2 ) between the at least one network component and the at least one energy storage to separate. Vehicle, in particular motor vehicle, with at least one electrical network according to claim 14.

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