Individual monitoring of plurality of output sites of system for supplying external load on vehicle side

Abstract

A method for monitoring at least one first and one second alternating current output point in a vehicle specifies the following steps: detecting a total alternating current (I0) output from an inverter (WR) to the output points (A1, A2) via a distribution point (V); and detecting at least one first alternating current (I1) flowing in the first output point (AS1). A second alternating current (I2) flowing in the second output point (AS2) is determined as a difference between the total alternating current (I0) and the at least one first alternating current (I1). The at least one first alternating current (I1) and the at least one second alternating current (I2) are compared with respective threshold values. If at least one of the comparisons indicates that a threshold value (SW) is exceeded, an overload signal (OS) is output. The invention further relates to a vehicle-based unit and to a vehicle charging circuit for carrying out the method.

Description

Background Art

[0001] It is known that vehicles are equipped with an onboard electrical system which, in addition to a high-voltage battery, also has an electric drive. It is also known that as an additional function, the energy of the battery can also be accessed for external loads, which is referred to as "Vehicle-to-load (V2L)".

[0002] For this purpose, outlets are usually used, for example in the form of common household sockets. Since high-voltage batteries have a very high power which is much higher than the common power for which household sockets are designed, the object of the present invention is to provide a possibility with which such a supply of power to external loads can be realized in a reliable manner. Summary of the invention

[0003] This object is achieved by the subject matter of the independent claims. Further properties, features, embodiments and advantages can be gathered from the dependent claims, the description and the drawings.

[0004] It is proposed to monitor a plurality of output locations (e.g. sockets) individually, which are connected to the inverter via a distribution location. It has been recognized that even if the total alternating current is within the rated range (e.g. up to 32 amperes), one of the output locations may still be overloaded if the current intensity of the load connected thereto exceeds the permissible current intensity. It is therefore proposed to take into account not only the generally known total alternating current, but also the alternating current of the first output location. The second alternating current at the second output location can be obtained as the difference between the total alternating current and the first alternating current. Not only the detected first alternating current but also the obtained second alternating current is compared with a threshold value, for example a maximum current intensity (e.g. 16 amperes), so that if the corresponding alternating current exceeds at least one of these threshold values, an overload signal is output. Therefore, for monitoring, it is not necessary to measure both output locations, but only the first alternating current at the first output location is detected, and the second alternating current can be calculated from the first alternating current (measured) and the total alternating current (also measured). The first alternating current is detected in terms of measurement or in terms of deriving a value from the measurement, wherein this also applies to the total alternating current. The second alternating current is only calculated, not measured, so that it is only obtained as the difference between the total alternating current and the first alternating current. If there are more than two output locations, i.e., n output locations, the alternating current is measured from n-1 output locations, and the alternating current of the remaining output locations is obtained by the difference between the total alternating current and the sum of the measured alternating currents. Therefore, the obtained difference is obtained from the total alternating current and the sum of all measured alternating currents. As an alternative, the inverter can include a distribution location, wherein this combination can be set as a vehicle charging circuit. Here, the inverter can be a power circuit that works as a (controlled) rectifier in charging mode.

[0005] A method for monitoring at least one first and second alternating current output locations in a vehicle is described. The alternating current output location is arranged in the vehicle and can be accessed to contact an external load. For example, an electric tool can then be operated with the aid of energy stored in the vehicle. In particular, the total alternating current is detected by measurement. The total alternating current is output from an inverter via a distribution location to the output location. Starting from the inverter, the power is distributed via the distribution location in the form of a plurality of power paths that each lead to the output location.

[0006] The inverter is fed in particular by the traction battery of the vehicle. The inverter is preferably a high-voltage inverter and is designed for operating voltages exceeding 60 volts, in particular 200, 400 or 800 volts. The inverter can be implemented by means of the charging circuit of the vehicle or by means of the traction inverter of the vehicle. Since such components contain controllable semiconductor switches, the corresponding inverter can be implemented by controlling these switches. The total alternating current is preferably detected in the alternating current side of the inverter or at the direct current side of the inverter by means of a measuring device in the inverter, wherein the value must then be converted by means of a coefficient in order to obtain the total alternating current. In addition, at least one first alternating current flowing in the first output portion is detected. Preferably, at least one first alternating current is measured by means of another measuring device. As a measuring device, a Hall element or a shunt resistor implemented as a current sensor can be considered in particular. A signal is generated at the Hall element or the shunt resistor, from which the flowing current can be derived. In addition, for this purpose, a measuring transformer or other inductive coupling device of a conductor with a relevant alternating current can also be considered. If a plurality of first alternating currents are present, they are detected or measured separately. For this purpose, the aforementioned devices can be used.

[0007] The second alternating current does not need to be measured, but is obtained, in particular calculated as the difference between the total alternating current and at least one first alternating current. If multiple first alternating currents are provided, the second alternating current is the difference between the total alternating current and all the first alternating currents (i.e., the difference between the second alternating current and the sum of all the first alternating currents). The acquisition can also be similarly achieved by a subtraction circuit. The second alternating current is an alternating current flowing to the second output portion. (At least one) first alternating current flows from the distributor portion to the first output portion, and the second alternating current flows from the distributor portion to the second output portion.

[0008] If a plurality of first alternating currents are provided, a plurality of first output locations are also provided, and vice versa. The first alternating current flows to the corresponding first output location. If additional output locations are provided, their alternating currents also flow from the distributor location to the relevant output locations. The second current is generated as the difference between the total alternating current and the first alternating current (or all measured first alternating currents). If there are additional loads in the vehicle electrical system, the current consumption of the additional loads can be subtracted from or added to the difference, so as to obtain the net difference between the total alternating current and all measured alternating currents.

[0009] The first alternating current is compared with an assigned threshold value, and the second alternating current is also compared with an assigned threshold value. The two threshold values ​​can be the same, in particular if the output locations are designed according to the same output power or according to the same current intensity. If all comparisons or only one of the comparisons or a subset of the comparisons indicate that the threshold value is exceeded, an overload signal is output. Thus, if at least one comparison indicates that the corresponding current value has exceeded the corresponding threshold value, an overload signal is output. The overload signal can be output specifically to the relevant output location where the alternating current exceeds the assigned threshold value. The overload signal can also be output in a debounced manner, that is, the threshold value must be exceeded for a minimum duration in order to trigger the overload signal.

[0010] The method involves at least one AC current output point and a second AC current output point, which are supplied by the same distribution point. If there are multiple first AC current output points, these first AC current output points are measured, that is, the first AC currents assigned to the first AC current output points are detected (for example by measurement). The second AC current is obtained as the difference between the total AC current and the sum of all first (measured) AC currents.

[0011] Here, the AC current output portion is also simply referred to as an output portion.

[0012] The first alternating current is preferably detected using a current sensor, which is arranged in a first plug device connected to the distribution site. The connection is preferably a plug-free connection. As an alternative or supplementary solution, the first alternating current can also be detected using a current sensor arranged in a second plug device. The second plug device is inserted into the first plug device, wherein the first plug device is connected to the distribution site (in a plug-free manner). In other words, the current sensor can be located in the first plug device, which is, for example, constructed as a power socket or a socket or can be arranged in a plug device inserted therein (such as a load plug or an adapter into which the load plug can be inserted).

[0013] As an alternative or in combination therewith, the first alternating current can be detected by means of a current sensor arranged in an intermediate adapter. The intermediate adapter is inserted into a first plug device which is connected to the distribution point (without a plug connection). In this case, the second plug device can be inserted into the intermediate adapter, so that the intermediate adapter connects the first plug device and the second plug device to one another. Thus, the intermediate adapter can have a connection in the form of a socket (socket) or a plug socket, into which the second plug device (i.e., for example, a load plug) can be inserted.

[0014] Thus, the current sensor can be arranged in a plug device that is designed in accordance with a common household socket. The current sensor can also be integrated into a load plug that is designed to be plugged into such a household socket. Finally, an intermediate adapter can be provided that has a socket in the form of a common household socket into which a load plug (for example, a second plug device) can be plugged. The current sensors are each arranged in such a way that they can detect the current flowing through the respective device or the current flowing through the intermediate adapter.

[0015] Here, sockets or (common) household sockets are sockets which are designed according to the NEMA 1-15, 5-15, 14-50R or 14-30R standards, or are designed to receive plugs according to CEE7 / 16 (Euro plug), or are designed to receive plugs according to CEE7 / 14, CEE7 / 5, CEE7 / 4 or CEE7 / 7. Other possible designs are sockets for receiving BS1363, SI-32, AS3112, SEV1011, DS60884-2-D1, CEI23-50, BS546, IEC60506-7 plugs, or sockets for refrigeration equipment plugs (IEC60320C13, 14, 19, etc.). In particular, common household sockets are designed according to national standards. In particular, single-phase AC sockets are called household sockets, which can be designed with or without protective contacts. Household sockets are actually designed for an AC voltage of at least 100 volts, for example for a voltage of 230 volts at 50 Hz.

[0016] At least one alternating current is transmitted to an evaluation unit. A signal reflecting the level of the alternating current is transmitted. The level of the alternating current is referred to as the effective current intensity, the current amplitude or the peak-to-peak current intensity. The signal can be transmitted by wire or wirelessly, directly or by changing the entity of the transmission protocol. In particular, at least one alternating current or a signal reflecting the alternating current can be transmitted via a CAN bus, an IP-based network or by other data transmission protocols. The signal can also be transmitted wirelessly, for example by means of a Wifi signal or by means of a Bluetooth signal or according to other wireless signals with standardized protocols.

[0017] The inverter can be configured as a bidirectional charging converter for a vehicle. In other words, the inverter can be configured as an AC charging circuit, which is bidirectional and can convert a DC current (such as a traction battery of a vehicle) into an AC current. Here, the charging converter or inverter is configured to output a power signal having a target rated voltage (such as 110, 120, 200, 220 or 230 volts) and a target frequency (such as 50, 60 or 100 Hz) as a total AC current. In particular, the inverter is configured to output a sinusoidal current as a total AC current. The inverter is configured to generate a total AC current by inverting the DC current provided by the DC power supply. The total AC current can be supplied by a DC voltage source, such as a battery such as a high-voltage battery, so as to generate a total AC current by inversion. In the case of the bidirectional direction of the charging converter, the charging converter has a lower power in the function of the inverter than in the reverse direction where it works as a rectifier.

[0018] The total AC current is generated by the inverter by inverting the DC current or DC voltage output by the traction battery. The traction battery then forms the DC power source. If the charging converter is operated in the reverse direction, the charging converter acts as a rectifier and is used to supply charging current to the traction battery.

[0019] A charging control unit can be provided which controls the inverter and is designed to operate the inverter bidirectionally. In particular, the charging control unit is designed to operate the inverter for inversion and for rectification (operation in the reverse direction).

[0020] A current sensor for detecting a first alternating current can be arranged in an adapter connected to a connection site. The adapter itself forms a connection site for an external load. The detected alternating current is transmitted from the adapter, in particular from a transmission unit of the adapter, to a charging control unit. It can also be provided that the first output site itself has a current sensor, wherein the adapter is inserted into the first output site. The adapter then provides a plug-in device, such as a socket, into which an external load can be inserted. The plug connection between the adapter and the output site (with the current sensor) can be proprietary and different from all standard power sockets, and can also have a standardized interface for inserting common load plugs. The adapter can have a transmission device, which is set up to transmit a value detected by a sensor (which reflects the intensity of the alternating current flowing through the adapter), such as to a distribution site, a charging control unit of a vehicle-based unit, or an evaluation unit as described here.

[0021] A distribution point can be provided in which the total alternating current is not only distributed into a first alternating current and a second alternating current, but also a current sensor for detecting at least one first alternating current is provided in the distribution point. Such a distribution point can be connected to a charging control unit for controlling the inverter in the form of data transmission. In general, the charging control unit can also be designed as a control device, which in particular has an evaluation unit as described here.

[0022] A vehicle-based unit is described, which is designed to implement the method. The vehicle-based unit is used to feed a load external to the vehicle by means of a vehicle-based energy storage device. In particular, the vehicle-based unit is designed to control such feeding. The vehicle-based unit has an evaluation unit, which has a total current measurement input and at least one single current measurement input. In addition, the evaluation unit has an output for outputting an overload signal. The evaluation unit has a subtraction mechanism, which is designed to form a difference from a current value applied to the total current measurement input (i.e., the total alternating current) and at least one current value applied to at least one single current measurement input (corresponding to at least one alternating current). In addition, a comparator is provided there, which is used to compare at least one current value at at least one single current measurement input and the difference with a corresponding threshold value. The comparator is designed to output an overload signal if at least one of the comparisons indicates that the corresponding threshold value is exceeded. Such a unit can be arranged in a charging control unit or can be connected before the charging control unit. As a vehicle-based unit, an intermediate adapter as described here can also be considered. Since the intermediate adapter is connected to the onboard electrical system of the vehicle, the intermediate adapter is considered to be vehicle-based here.

[0023] In particular, a charging circuit control unit can be provided, which is connected to the inverter in a controllable manner and is designed to control the inverter for controlled rectification (for example, according to a target voltage or a target current on the DC voltage side). In addition, the charging control unit is designed to operate the circuit as an inverter in order to transmit power in the opposite direction. If the charging control unit includes a vehicle-based unit or is connected after the corresponding unit, it can be provided that the charging control unit reduces the power or switches off the inverter if at least one of the threshold values ​​in the vehicle-based unit is exceeded. The following device is described here as a vehicle-based unit, which is designed to be arranged in a vehicle, in particular in an onboard power supply control unit or an onboard power supply. The unit is used to feed a load external to the vehicle in such a way that the unit is designed to control the inverter or monitor the current output from the inverter (including the individual currents at the output point). One embodiment provides that, in addition to the load connected to one of the output points, a load inside the vehicle can also be connected to the inverter in order to operate the load inside the vehicle with an alternating current. In this case, the current of the load inside the vehicle is preferably also measured and taken into account as an additional load within the monitoring, in particular as a load added to the total alternating current conducted through the distribution point. Overloads caused by internal loads together with external loads can thus be monitored.

[0024] The method can also be implemented in a vehicle charging circuit, in particular a bidirectional vehicle charging circuit. Such a vehicle charging circuit has a controlled rectifier, which rectifies the charging AC current in the charging state of the circuit (for example, in the AC charging state) in order to output the rectified current to the DC connection of the charging circuit (and the battery connected thereto if necessary). In the feedback state of the circuit, the rectifier works as an inverter, in particular as an inverter as described herein. In the feedback state, the rectifier works as an inverter, which generates an AC current at the AC connection or the AC side of the rectifier (at the corresponding phase potential of the circuit) starting from the DC voltage at the DC connection. The distribution point is connected to the AC side of the rectifier. Starting from the AC side of the rectifier, the distribution point leads to at least one first AC connection on the one hand and to a second AC connection on the other hand. The distribution point connects these connections to the rectifier. The AC current output point can be connected to the first and second AC connections; the vehicle charging connection can be connected to one of the AC connections in particular. The connector is constructed for this purpose, in particular in terms of the design of the electrical conductivity (the electrical conductivity should be designed to be higher when connected to the vehicle charging connector than when connected to the AC current output site). The first current sensor acquires the total AC current between the rectifier (which operates as an inverter) and the distribution site. At least one second current sensor acquires at least one first AC current flowing from the distribution site to at least one first AC connector. The difference mechanism of the circuit acquires the AC current flowing from the distribution site to the second AC connector as the difference between the total AC current and the first AC current (or the sum of all measured first AC currents). The comparator of the circuit compares at least one (measured) first AC current with an assigned threshold value. The comparator also compares the (acquired) second AC current with the assigned threshold value. If one of the threshold values ​​is exceeded, the circuit is set up to output an overload signal at the (signal-) output end of the circuit. In addition, the comparator can be set up to also compare the total current with the assigned threshold value so as to output an overload signal when the threshold value is exceeded (especially at the output end).

[0025] The threshold value of the AC current flowing between the distribution point and the vehicle charging connector is preferably greater than the threshold value of the AC current flowing between the distribution point and one of the AC current output points. It is therefore particularly conceivable that in some embodiments, the maximum current fed back to the power supply network via the vehicle charging connector is greater than the maximum current that can be output via the AC current output point.

[0026] The vehicle charging circuit is in particular an AC charging circuit. The vehicle charging circuit is designed for bidirectional rectification. A vehicle charging connector is a connector that is designed for (AC) charging of a vehicle. With the circuit described here, this connector is also used for feedback. Therefore, the phrase "vehicle charging" should not limit its function and design to charging, but only define that it is suitable for charging in addition to feedback. The vehicle charging connector can also be called a vehicle connector or a vehicle charging connector and feedback connector. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 For explaining the methods and apparatus described herein in more detail. DETAILED DESCRIPTION

[0028] Figure 1 An inverter WR and a DC voltage source GQ are shown. The total AC current I0 output by the inverter is directed to a distributor point VP of a distribution site V. The power path is divided at or within the distributor point VP and generates a first AC current I1 and a second AC current I2. These currents are directed to a first output site AS1 (current I1) and a second output site AS2 (current I2). Loads K1 and K2 are connected to these output sites. Here, the first current is directed from the distributor site V to a first socket or plug-in device B1. The second plug-in device S1 is inserted into the first socket or plug-in device. The second plug-in device is constructed complementary to the first plug-in device. The second plug-in device S1 can be a plug. The plug can be directed to a wire, which is in turn connected to the assembly K1. Therefore, the second plug-in device S1 can be a plug-in device assigned to the load K1. In particular, the first plug-in device is constructed according to a common household socket. The second output point AS2 also has a similar structure, with a first plug device B2 and a second plug device S2 plugged into the first plug device B2. The second component K2 can be a load, whose plug (second plug device S2) is plugged into the plug device B2.

[0029] One specific embodiment provides that only the first plug-in devices B1 , B2 are part of the output region and thus part of the vehicle electrical system, whereas the second plug-in devices S1 , S2 are external plug-in elements of external loads.

[0030] A feasible scheme provides that the current sensor according to the reference numeral a is arranged in the first plug device B1 to detect the current flowing through the plug device B1 as the first alternating current. As an alternative, the current sensor can be arranged as shown in the reference numeral b. In this case, the current sensor b is in the second plug device. At least the current sensor b - if it is not also the second plug device in addition - is preferably regarded as the first output part AS1 and therefore as the vehicle on-board power system. Therefore, the current sensor can be arranged in the first plug device or the second plug device of the output part. Another feasible scheme is shown in the dotted frame in the upper right corner. An alternative first output part AS1' is shown there. The alternative first output part has a first plug device B1. The intermediate adapter Z is inserted into the first plug device. Then, the second plug device S2 (leading to the load K1) is inserted into the intermediate adapter Z again, so that the intermediate adapter Z connects the components B1 and S1. In the embodiment shown, the current sensor c is arranged in the intermediate adapter. The intermediate adapter Z can have a transmission device T, which is designed to transmit the current value detected by the current sensor c, in particular to the unit E. If the intermediate adapter Z is connected to the plug device B1, for example, the intermediate adapter Z can then transmit the measured current value I1 to the unit E via the transmission device T. For this purpose, the sensor c is preferably connected to the transmission device T in a signal transmission manner. The transmission device T can be designed for wired or wireless data transmission. In order to receive the current value sent by the transmission device T, the unit E preferably has a receiver, which can be connected before the input S, or the receiver forms the input S. The receiver is designed to receive signals according to a data transmission protocol, which is also used by the transmission device T for data transmission.

[0031] Another possible solution is to place the current sensor in the distribution point V, as indicated by reference numeral d. There, the current sensor is arranged in the power path or coupled to it in a current-detecting manner. The power path leads from the connection point VP of the distribution point V to the first plug device or the first output point AS1.

[0032] The inverter is set up to obtain the total alternating current I0 by measurement or by calculation according to the current operation. It is stipulated that the current I2 is obtained by forming the difference between I0 and the measured current I1. Not only the current I1, but also the current I2 is compared with the corresponding threshold value, which corresponds to the rated current or maximum current of the connected output part, for example. They can also be equal, for example, 16 amperes. If only one of these values ​​exceeds the corresponding threshold value, an overload signal US is also output. This can cause the control unit of the inverter WR to deactivate the inverter or at least reduce the power of the inverter. In particular, it can also be stipulated that the output part through which the alternating current exceeding the threshold flows is separated. For this purpose, a switch can be provided, which is connected after the vehicle-based unit, for example.

[0033] The vehicle-based unit can be configured to feed the internal load of the vehicle. The vehicle-based unit can be constructed as a pure control unit, which can be connected to the inverter in a controlled manner to present its function, or it can also be configured as a power unit including an inverter. In particular, an evaluation unit E can be provided, which can detect not only the total alternating current I0, but also at least one alternating current I1. For this purpose, the evaluation unit has an input terminal in the form of a total current measurement input terminal G for the total alternating current, and also at least one single current measurement input terminal S for detecting the current I1 (first alternating current). The corresponding data transmission connection is shown in a symbolic manner with a dotted line. Unit E can be part of the inverter WR or the control unit of the inverter WR. The unit also has a subtraction mechanism M, which obtains relevant values ​​from the single current measurement input terminal S and the total current measurement input terminal G in order to subtract these values ​​from each other. The difference formed is input to the comparator x. The comparator x compares the difference corresponding to the current I2 with the assigned threshold value. In addition, the single current measurement input S is also connected to the comparator x, so that the comparator x can also compare the current I2 (received through the single current measurement input S) with the assigned threshold value. The comparator x is set up to output an overload signal OS if at least one of the threshold values ​​is exceeded. For this purpose, the comparator can be provided with a current-individualized output interface, which indicates that at least one threshold value has been exceeded, and preferably also indicates which current (I1 or I2) has exceeded the threshold value, so as to adjust the relevant output position, for example, by a control unit not shown. The comparator x is also configured in particular to compare the total current measurement input or the current I2 with the relevant (higher) threshold value, so as to be able to detect an overload of the inverter WR. However, this feasible solution is only provided in a specific embodiment, while other embodiments do not provide for comparing the total alternating current I0 with the assigned threshold value.

[0034] At least one internal AC socket can be provided in a vehicle or in a vehicle onboard power system. The AC socket corresponds in particular to one of the output locations. A plurality of such output locations can also be provided. The total current, i.e., the sum of the AC currents flowing through the relevant output locations, can be centrally measured using only one current sensor, in particular a current sensor provided before the distribution location V. The input lines leading to all output locations can be provided with the same power cross-section, for example, designed for a specific rated current intensity or maximum current intensity. The rated current intensity or maximum current intensity can be, for example, 10 amperes. If all the input lines leading to the output locations are designed identically (for example, in terms of electrical conductivity), then the threshold value or the relevant output location or plug-in element can also be designed for the same current intensity.

[0035] In particular, an intermediate adapter can be provided which has not only a current sensor but also a transmission unit for outputting the measured current. In this way, an output connected thereto can be authorized to output a current which is limited only by the method described here and not by fuses etc. In other words, such outputs can be protected with a higher current intensity than that reflected by the associated threshold value.

[0036] An onboard power system can be provided, which includes an inverter having a DC voltage input for connecting a battery. In addition, the onboard power system has the components described here, in particular output locations AS1, AS2 and a distribution location V. Such an onboard power system can also be equipped with a vehicle-based unit as described here and / or an evaluation unit E as described here. The unit can also be arranged in an intermediate adapter. In other words, the intermediate adapter can be equipped with a unit, or with a subtraction mechanism M, a comparator x, a total current measurement input G and / or a single current measurement input S.

[0037] If the distribution point and the inverter are integrated in a common circuit (such as a vehicle charging circuit), the first sensor detects the current I0 and the second sensor detects the AC current I1. The AC current I2 can be calculated as a difference. The currents I1, I2 measured and calculated in this way can then be compared with threshold values, and if at least one of the threshold values ​​is exceeded, an overload signal OS can be output. One embodiment provides that the common circuit has: a first AC connector, to which the vehicle charging connector is connected; and a second AC connector, to which the AC current output point is connected. The vehicle charging connector can also be used to feed back the AC current to an external AC power grid. The check performed with the aid of the threshold value allows the current flowing to the vehicle charging connector and the AC current output point to be monitored separately in the following aspects, namely: an overload signal is output when the corresponding threshold value is exceeded.

Claims

1. A method for monitoring at least one first alternating current output location and a second alternating current output location in a vehicle, the method comprising the following steps: Detecting a total AC current (I0) outputted from an inverter (WR) via a distribution portion (V) to the output portion (A1, A2); detecting at least one first alternating current (I1) flowing in the first output portion (AS1); obtaining a second alternating current (I2) flowing in the second output portion (AS2) as a difference between the total alternating current (I0) and the at least one first alternating current (I1); and The at least one first alternating current (I1) and the second alternating current (I2) are compared with corresponding threshold values ​​and an overload signal (OS) is output if at least one of the comparisons indicates that the threshold value (SW) is exceeded.

2. The method according to claim 1, wherein: The first alternating current (I1) is detected by a current sensor (a) which is arranged in a first plug-in device (B1) connected to the distribution point (V), or the first alternating current (I1) is detected by a current sensor (b) which is arranged in a second plug-in device (S1) which is inserted into the first plug-in device (B1) connected to the distribution point (V).

3. The method according to claim 1, wherein: The first alternating current (I1) is detected by means of a current sensor (c) arranged in an intermediate adapter (Z), which is plugged into a first plug device (B1) connected to the distribution point (V) and into which a second plug device (S1) is plugged.

4. The method according to claim 1, wherein: The first alternating current (I1) is detected by means of a current sensor (d) which is arranged in the distribution point (V) in a power path leading from a connection point (VP) of the distribution point to a first plug-in device (B1).

5. A method according to any one of the preceding claims, wherein: The first alternating current (I1) is transmitted to an evaluation unit (E) as a signal reflecting the level of the alternating current, wherein the signal is transmitted by wire or wirelessly.

6. A method according to any one of the preceding claims, wherein: The inverter (WR) is a bidirectional charging converter of the vehicle, and the total AC current (I0) is generated by the inverter (WR) by inverting the DC current of the DC power source (GQ).

7. The method according to claim 6, wherein: The total AC current (I0) is generated by the inverter (WR) by inverting a DC current output from a traction battery operated as a DC power source (GQ).

8. A vehicle-based unit for feeding vehicle-external loads (K1, K2) with the aid of a vehicle-based energy store (GQ), the vehicle-based unit having an evaluation unit (E) having a total current measurement input (G) and at least one single current measurement input (S) and an output for outputting an overload signal (OS), wherein: The evaluation unit (E) has a subtraction mechanism (M) which is designed to form a difference between the current value at the total current measurement input and the current value at the single current measurement input, and further has a comparator (x) for comparing the current value at the single current measurement input and the difference with corresponding threshold values ​​(SW) and outputting an overload signal (OS) if at least one of the comparisons indicates that the corresponding threshold value (SW) is exceeded.

9. A vehicle charging circuit having a controlled rectifier, which is designed bidirectionally and has at least a first alternating current output connection and a second alternating current output connection, wherein: One of the connections is designed for connection to an alternating current output location (AS1), and the other of the connections is designed for connection to a vehicle charging connection or to a further alternating current output location (AS2), The vehicle charging circuit comprises a distribution point (V) which is connected to the rectifier and connects the rectifier to the AC current output point (AS1) and to the vehicle charging connector or the further AC current output point (AS2). wherein a first current sensor of the vehicle charging circuit is designed to detect a total alternating current (I0) flowing between the rectifier and the distribution point (V), and a second current sensor of the vehicle charging circuit is designed to detect a first alternating current (I1) flowing between the distribution point (V) on the one hand and the first alternating current output connection on the other hand or between the distribution point (V) on the one hand and the vehicle charging connection or the second alternating current output connection on the other hand, The vehicle charging circuit has a difference mechanism, which is configured to obtain a second alternating current as a difference between the total alternating current (I0) and the first alternating current (I1), and Therein, the vehicle charging circuit has a comparator which is designed to compare the first alternating current and the second alternating current with corresponding threshold values ​​and to output an overload signal (OS) at a signal output of the vehicle charging circuit if at least one of the comparisons indicates that the corresponding threshold value (SW) is exceeded.

10. The vehicle charging circuit according to claim 9, wherein: A threshold value of the alternating current flowing between the distribution point (V) and the vehicle charging connector is greater than a threshold value of the alternating current flowing between the distribution point (V) and one of the alternating current output points.

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