WO2024023203A1

WO2024023203A1 - Electric circuit and operating method

Info

Publication number: WO2024023203A1
Application number: PCT/EP2023/070816
Authority: WO
Inventors: Fabian Schnabel
Original assignee: Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
Priority date: 2022-07-29
Filing date: 2023-07-27
Publication date: 2024-02-01
Also published as: DE102022207897A1

Abstract

The invention relates to an electric circuit (10, 10', 10'') having the following features: a converter circuit (12, 12', 13') which is located between a first potential tap (16a) and a second potential tap (16b) and comprises a plurality of switches (14), wherein a battery (20) can be coupled via the first potential tap (16a) and/or the second potential tap (16b), wherein the first and/or the second potential tap (16b) comprise(s) an additional switch (28, 28', 28''); a voltage terminal (22) which is connected to the converter circuit (12, 12', 13'); a fault-current/fault-voltage detection unit (24) which is coupled to the voltage terminal (22) and is designed to detect a fault current or fault voltage; a controller (26) which is designed, when a fault current or fault voltage is detected by the fault-current/fault-voltage detection unit (24), to perform a turn-off sequence according to which the additional switch (28, 28', 28'') of the first and/or the second potential tap (16b) as well as at least one of the switches of the converter circuit (12, 12', 13') are opened.

Description

Electrical circuit and operating procedures

Description

Embodiments of the present invention relate to a circuit with a power converter circuit and shutdown sequence as well as a corresponding method for operating a power converter circuit and computer program.

Preferred exemplary embodiments relate to a circuit arrangement for detecting and switching off DC fault currents.

When operating non-insulating rectifiers (AC-DC conversion, unidirectional or bidirectional), pulsating DC residual currents or DC residual currents can arise due to insulation faults on the DC voltage side. When using TYPE AC or A residual current circuit breakers, these can lead to saturation of the magnetic core of the converter. This means that the residual current circuit breaker can no longer detect and switch off any residual current that may be present (“blinding” the RCD).

Figures 1a and 1b illustrate bridge circuits in which fault currents can occur. Fig. 1a shows a six-pulse bridge circuit 100, which is arranged between two potential taps 102a and 102b. A direct voltage can be provided between the potential taps 102a and 102b based on an alternating voltage present at the alternating voltage inputs of the bridge circuit 100. This drops across the consumer/resistor 106. The voltage existing between the potential taps and PE 104 results in a current i _F in the event of an insulation fault. For example, the fault current can occur with both an insulation fault of 102a and 102b - the choke 106 leads to a smoothing of the current depending on the inductance value. The residual current is marked as direct residual current i _F in the diagram opposite.

The situation is analogous with the battery charger shown in FIG. 1 b, which also has a bridge circuit 100 between two potential taps 102a and 102b. The battery 108 is charged in series with the smoothing inductor 106. The DC residual current i _F smoothed by the inductor 106 is shown in the associated diagram. A publication [1] described the structure of a charger with galvanic isolation, as shown in Fig. 2. There are three areas B1, B2 and B3, with the areas B2 and B3 being separated by a transformer 120. All areas B1, B2 and B3 are arranged in a common housing 122. The area B1 includes the AC voltage input with appropriate filtering. The rectifier 124 and another power converter circuit 126 are arranged in area B2. The further converter circuit 126 essentially serves to operate the transformer 120. An analog converter circuit 128 is provided in area 3 on the secondary side of the transformer.

For a charger without galvanic isolation, the galvanically isolated area 3 is omitted, as shown in connection with FIG.

3 shows a charger with areas B1 and B2, both of which are provided in the common housing 122. The last voltage connection including filtering is again provided in area B1. The area B2 houses the power converter circuit, here a rectifier 124. The rectifier direct voltage is then output to a battery without galvanic isolation. Both in the variant from FIG. 2 and in the variant from FIG. 3, a coupling can be provided via a cable 130 with a cable shield.

In both variants of FIGS. 2 and 3 , potential insulation breakthroughs between circuit components in the areas B1, B2 and B3 and in the housing 122 are shown as examples using arrow symbols. Fault currents in area B1 are avoided by state-of-the-art means or can be detected and switched off by an RCD-A, as explained with reference to FIG. 4.

4 shows a power converter circuit 124 with the AC voltage input or AC voltage filter 134. This can, for example, have a common mode filter 1341, a push-pull filter 134r and one or more capacitances 134c. This AC voltage connection or input filter 134 of the charger is connected via a charging station 140 to the supply network 150, here for example a TN-C network or TN-CS. Two errors are shown as examples. Error 1 represents an insulation fault in the input filter against the housing 122 of the charger, which is grounded via the protective conductor, and can be detected and switched off by a typical RCD-A 142, which is arranged, for example, in the charging column 140. The The same applies to a double fault in which there is an internal insulation fault and an interrupted protective conductor at the same time. If a person touches the housing 122, error 2 is triggered and a contact current flows across the person in a closed circuit.

Fault currents in area B2 occur on the DC voltage side and lead to “blindness” of the RCD-A, as will be explained below with reference to Fig. 5. 5 again shows the power converter circuit 124 with the AC voltage filter 134, which is connected to the supply network 150 via the charging station 140.

In addition to the power converter circuit 124, the charger has a further power converter circuit or a further part of the power converter circuit 126 (see above) in front of the transformer 120, via which a battery can be coupled (cf. battery system 131). The part of the power converter circuit 124 is connected to the part of the power converter circuit 126 via the common potential taps 124a and 124b. In addition, an intermediate circuit 124z can also be provided.

Two errors are shown here as examples, namely an error 1 as a short circuit between the voltage tap 124a or 124b and the housing 122 and an error 2 in which the protective conductor connection to the housing is interrupted at the same time (see double lines in Fig. 5), so that a dangerous Contact current can flow over the person. Due to the blinding, the fault currents with a direct component cannot be detected, in contrast to the AC voltage faults from FIG. Personal safety is at risk.

There are some approaches in the prior art to overcome these problems. These are shown, for example, in FIG. 6, which is based on the topology from FIG. 3.

6 shows a charger with the power converter circuit 124 with the AC voltage input 135, the battery 131 or the battery system 131 being connected directly via a cable 130. The charger is coupled to the power grid 150 via a charging station 140. In this exemplary embodiment, the charging station 140 again has the RCD-A 142, for example. The AC voltage input 135 has an RCM-B 135r. This can carry out DC residual current measurements within the device. When using contactors/relays, the long response time until interruption can be problematic (typically 5 to 40 ms). During this time, the fault current in the event of a low impedance insulation fault can already reach current values for which the contactor or the diodes of the converter circuit 124 are no longer designed. On the current increase The filter chokes of the converter circuit have a limiting effect at first. In order to avoid saturation of the chokes and damage to the converter circuit 124, the power must be switched off very quickly. Especially when using wide-bandgap semiconductors with high switching frequencies, the inductance of the filter chokes is very small and the current rise is higher. In order to be able to safely switch off the fault current, fast reaction times are required.

In addition, the components of the charger, in particular the converter circuit 124, the high-voltage vehicle electrical system 130 and the battery system 131 are designed using double insulation. This is provided with the reference number 133. This solution is also suitable without the galvanic isolation, that is, the structural separation from the high-voltage electrical system 130 and 131, as is present, for example, in FIG. 5. Therefore, for example, the insulation 133 extends not only over the rectifier 124, but also the components of the high-voltage vehicle electrical system 130 and 131.

Patent US 2012/028674.0 A1 from Renault describes a charger without galvanic insulation. An excerpt of the circuit arrangement for non-isolated chargers is shown in Fig. 7.

Fig. 7 shows a non-insulated charger with an AC voltage input 5, a first converter circuit 6 and a second converter circuit 7 as well as inductors 14 in between. The circuit 6 has bucking behavior. The switches 12 and the diodes 11 are connected so that the current can be switched off in both directions. A fault current on the DC side can be quickly switched off via the semiconductor switches after detection with the RCM-B. However, the rectifier circuits commonly used have boosting behavior. With these it is not possible to switch off the current flow with the semiconductors in both directions. Therefore, there is a need for an improved approach.

Embodiments of the present invention are based on the object of improving the fault behavior in the case of DC voltage side insulation faults or fault currents for electrical circuits, such as chargers.

The task is solved by the subject matter of the independent patent claims. Embodiments of the present invention provide an electrical circuit, such as a charger with a power converter circuit, a voltage connection, such as an AC voltage connection, a residual current/voltage detection unit, and a controller. The power converter circuit is arranged between a first potential tap and a second potential tap and has a plurality of switches. For example, the power converter circuit can have an H4 or B6 topology and can be designed to provide a direct voltage to the first and second potential taps based on an alternating voltage present at the voltage connection and/or in particular have a step-up behavior. Other voltage conversions, such as DC-AC voltage conversion or DC-DC conversion, are of course also conceivable. A consumer (e.g. a battery) or a source (e.g. a battery, photovoltaic, fuel cell) can be coupled via the first and/or the second potential tap. The first and/or the second potential tap has an additional switch. The fault current/fault voltage detection unit is coupled to the voltage connection (which in turn is coupled to the power converter circuit) and is designed to detect a fault current (or possibly a fault voltage). For example, it can be an RCM (residual current monitor) differential current sensor. The controller is designed to execute a shutdown sequence in the event of a fault current or fault voltage detected by the fault current or fault voltage detection unit, according to which the additional switch of the first and/or the second potential tap as well as at least one of the switches of the power converter circuit is opened. According to a preferred exemplary embodiment, all switches of the power converter circuit are opened.

Embodiments of the present invention are based on the knowledge that by controlling the power converter circuit and opening the corresponding switches in the event of a fault current in combination with the opening of a switch in the first and/or second potential tap, practically all voltage or current sources are decoupled, so that The danger potential is significantly reduced even for chargers that are not galvanically isolated. According to exemplary embodiments, the fault current/fault voltage detection unit is designed to detect a direct current. Advantageously, a fault current can be quickly interrupted in both the positive and negative paths through the rapid device-internal detection. This allows the semiconductors and the AC relays to be switched off in the event of a short circuit on the DC side. be protected. This also eliminates the need for an additional, expensive “high speed circuit breaker” on the DC side. The simple switch in one of the potential taps is significantly more cost-effective than this circuit breaker.

Due to the quick error shutdown, the error can probably occur! Reference source could not be found, double insulation of the HV electrical system and battery system shown is omitted and basic insulation is used as usual. This can save additional costs for double insulation, which makes the use of non-insulating rectifiers, e.g. in chargers, financially unattractive despite their potentially lower overall costs. The normative assessment of this security aspect is currently being processed.

According to exemplary embodiments, the power converter circuit has a rectifier (on one side) and/or a DC-DC converter (on the other side). Both can be connected, for example, via the first and second potential taps. According to the exemplary embodiments, the additional switch is arranged between the rectifier and the DC-DC converter in one of the potential taps. Alternatively, the switch could also be arranged behind the DC-DC converter. However, the current is higher there, i.e. in front of the DC-DC converter. Which is why the arrangement in between seems advantageous. With regard to the DC-DC voltage converter, it should be noted that, according to exemplary embodiments, it can have a center tap. According to exemplary embodiments, a battery can be coupled via this direct voltage to direct voltage converter. For example, on the side of the first potential tap, the battery can be connected to a first pole of the battery with the first potential tap (generally: part of the input/output of the DC-DC converter, via which a battery/load/source can be coupled), the second The battery terminal is connected to the center tap. Alternatively, it would also be conceivable that the battery on the side of the second potential tap is connected to the second pole in the second potential tap (second part of the input/output of the DC-DC converter), in which case the first pole of the battery is connected to the center tap of the DC voltage -DC voltage converter is connected. Since a switch from the DC-DC converter is used, only another semiconductor switch with a diode is necessary. Since this is permanently switched on during normal operation, there are no additional switching losses that would reduce the efficiency of the rectifier. The conduction losses that occur are when using a low conductivity The loss of an optimized switch is low and comparable to the conduction losses that would occur in additional fuses or circuit breakers. At this point it should be noted that the DC-DC converter can also be designed differently, for example only a switch and a diode can be provided in the opposite direction to the rectifier.

According to exemplary embodiments, the at least one switch of the power converter circuit and/or the additional switch is implemented as a parallel connection of an active element (transistor) with a diode (e.g. IGBT) or as an active element with an intrinsic diode (e.g. MOSFET). According to one exemplary embodiment, the diodes associated with the switches of the power converter circuit on the respective first or second side of the potential tap (or the switch of the rectifier on the respective first or second side of the potential tap) are opposite to the diode of the additional switch and/or opposite to the Diodes of the DC-DC voltage converter are arranged. This can prevent a corresponding current flow from occurring when the switch is open. It should be noted at this point that a bidirectional blocking switch would also be possible.

Further embodiments provide a battery charger or a non-insulating battery charger or a battery charger with a non-isolated rectifier or another application comprising the (electrical) circuit as discussed above, e.g. electrolysis rectifiers, PV inverters, etc.

A further exemplary embodiment creates a method for operating the (electrical) circuit. The method includes the step of executing a shutdown sequence in the event of a fault voltage or fault current detected by the fault current/fault voltage detection unit, the corresponding shutdown sequence opening the additional switch of the first and/or second potential tap and at least one of the switches or preferably all switches of the power converter circuit become. Further exemplary embodiments relate to a computer program for carrying out the corresponding method.

Embodiments of the present invention are explained below with reference to the accompanying drawings. Show it: Fig. 1a/1b schematic representations of rectifier circuits to illustrate DC residual currents ip (see [1]);

Fig. 2 shows a schematic structure of a charger with galvanic insulation (see [1]);

Fig. 3 is a schematic representation of a charging configuration without galvanic isolation (see [1]);

4 shows a schematic enlargement of the configuration from FIGS. 2 and 3 in parts of area 1 for error observation;

Fig. 5 shows a schematic enlargement of the topography from Fig. 2 for fault analysis in area 2 (DC link with direct current component);

6 shows a schematic representation of a charger without galvanic isolation between the supply network and the HV network (implementation example includes an AC/DC converter (Bridgeless PFC) according to [1]);

7 shows a circuit arrangement for non-insulating chargers according to the prior art;

8 shows a schematic representation of an electrical circuit according to a basic exemplary embodiment;

9 shows a schematic representation of a circuit for a charger without galvanic isolation with a DC-DC converter and battery at the negative intermediate circuit potential according to an expanded exemplary embodiment; and

Fig. 10 is a schematic representation of a circuit for a charger without galvanic insulation with DC-DC conversion and battery at the positive intermediate circuit potential according to an expanded exemplary embodiment.

Before exemplary embodiments of the present invention are explained below with reference to the accompanying drawings, it should be noted that the same elements and Structures are provided with the same reference numerals so that the description of them can be applied to one another or interchangeable.

Fig. 8 shows a circuit 10 with a power converter circuit 12, which here has two half bridges 12a and 12b. The half bridges 12a and 12b and thus the converter circuit 12 are arranged between two potential taps 16a and 16b. A battery 20 can optionally be coupled via these two potential taps 16a and 16b. The battery 20 is connected, for example, with a first pole to the first voltage tap 16a and with a second pole to the second voltage tap 16b. In between, an additional switch 28 'is arranged in the voltage tap 16b (between the second pole and 16b), which will be discussed later. According to exemplary embodiments, a switch 28″ of an analogous position can alternatively or additionally be provided on the potential tap 16a (between the first pole and 16a). Depending on the version, the switch 28' or 28" can be part of the DC-DC converter, as will be explained below.

On the opposite side of the power converter circuit 12, that is, for example, on the input side, assuming that the battery 20 is provided on the output side (which is typical for battery chargers), a voltage connection 22, here for example an AC voltage connection, is provided.

There is a detection unit 24 at the voltage connection 22, which is connected to a controller 26. The controller 26 is used to control or supports the control of the switchable elements 14 and the switch 28 'or the optional switch 28" in one of the two potential taps 16a and 16b, here in the potential tap 16b, namely between the converter circuit 12 and the DC voltage side or the battery 20. Optionally, the voltage input 22 can also have relays 27 for disconnecting from the network. These are controlled by the controller 26 and, for example in the event of a fault, decouple the converter circuit 12 from the network 22. Each switch can have a diode connected in parallel, as shown, for example, in FIG.

Now that the structure has been explained, how it works will be discussed.

The power converter circuit 12 represents, for example, a rectifier which is designed based on an alternating current applied to the alternating voltage connection 22. Voltage to provide a DC voltage at the potential taps 16a and 16b. Both the function as a step-up converter and a step-down converter would be theoretically conceivable. It should be noted that a buck rectifier topology as shown in FIG. 7 can turn off current in both directions, according to embodiments. For this purpose, the switchable elements 14 in the half bridges 12a and 12b are controlled accordingly. The control can be carried out, for example, by the control unit 26 or another control unit. In this respect, a battery charger is realized through this structure. It should be noted at this point that not only rectification would be possible as conceivable modes, but also DC-DC conversion or a combination of rectification with DC-DC conversions.

The fault current/fault voltage detection unit 24 can, for example, be connected to the voltage connection and is designed to detect a fault current (or possibly a fault voltage). Examples of a recognizable fault current is an insulation fault between one of the voltage taps 16a or 16b and ground. This leads to a fault current on the high-voltage side, which is detected by the fault current/fault voltage detection unit 24. The unit 24 can be implemented, for example, in the form of a differential current sensor RCM (residual current monitor).

If a fault current is identified accordingly, a so-called switch-off procedure is triggered by the controller 26. This switches off the or preferably the additional switches 28' and 28" as well as at least one or preferably more of the switches 14 of the power converter unit. For example, the four switches 14 on the side of the potential tap 16a or preferably all switches 14 can be opened.

As shown in Fig. 8, a so-called overvoltage protection 28ü can be provided in parallel with the additional switches 28', 28" or associated with the additional switch 28', 28". The background is that switching off in combination with inductors can lead to an overvoltage, which is dissipated via this overvoltage protection. An example of a surge protector is a varistor.

Referring to FIG. 9, an expanded embodiment will be explained. Fig. 9 shows a charger 10' with a power converter circuit that includes a first part 12' and a second part 13'. Part 12' is a B6 rectifier connected to three phase inputs 22a, 22b and 22c. The phase inputs 22a to 22c are each connected to center nodes of the half bridges of the rectifier 12' via inductors 23. One of the half bridges 12c is explained as an example for all half bridges. Each half bridge 12c has two switchable elements 14' connected in series. These are implemented here, for example, by a parallel connection of a switchable element with a respective diode. The center tap is located between the switchable elements 14', via which the respective phases 22a, 22b and 22c are coupled.

The further part of the power converter circuit 13' forms a DC-DC converter, which is also formed by a comparable half-bridge. All half bridges 12a to 12c and the half bridge 13' are arranged in parallel between the two potential taps 16a and 16b. It should be noted at this point that an intermediate circuit capacitance 15 can optionally also be provided between the potential taps 16a and 16b.

The battery 20 is provided on the output side of the DC-DC converter 13 'and in this exemplary embodiment in such a way that the first pole of the battery, here the positive pole, is directly connected to the DC-DC converter 16a, while the second pole (here the negative pole) is connected via a Inductance is coupled to a center tap of the half bridge 13 'of the DC-DC converter.

As already explained in connection with the exemplary embodiment from FIG. 8, the fault voltage/fault current detection device 24 is provided on the input side, that is to say at the phase connections 22a, 22b and 22c, which are connected to the mains connection 25. The corresponding evaluation is provided with the reference number 26 and is designed to open the switches 14 'of the power converter circuits 12' or 13' in the event of the detection of a fault current or a fault voltage. In addition, an additional switch 28' is provided in one of the potential taps, here the potential tap 16a. When arranging the additional switch 28', it is chosen so that it is preferably provided between the rectifier 12' and the DC-DC converter 13', specifically on the side on which the pole of the battery is directly connected to the respective potential tap 16a is connected. This means, in this exemplary embodiment, in which the battery 20 is coupled directly to the potential tap 16a, that the switch 28' controls the potential tap 16a can separate. As can be seen, here again the switch 28' can be provided by a combination of parallel-connected switches and diodes (eg IGBT) or a switch with an intrinsic diode (eg MOSFET). The diode is in turn arranged so that it blocks the switch 14 'opposite to the diode direction. With regard to the arrangement of the switch, it should be noted that the switch can theoretically be placed to the left of the intermediate circuit 15 or between or after the DC-DC converter, although the placement explained above has proven to be best (current load, intermediate circuit connection to the rectifier 12).

The reverse arrangement of the additional switch is shown in Fig. 10. The topology of Fig. 10 represents the more common topology compared to Fig. 9.

Fig. 10 shows another charger 10", in which the two parts of the converter circuit 12' and 13' are provided. These are connected to one another via the voltage taps 16a and 16b, with the voltage tap 16b comprising the additional switch 28″ in this exemplary embodiment. For the sake of completeness, it should be noted that the connection of the converter circuit 12' to the AC voltage network 25 also takes place via the three-phase connection 22a, 22b and 22c, with these phase connections 22a, 22b, 22c providing error detection 24 and subsequent evaluation 26. Each of the phase connections 22a, 22b and 22c has a corresponding inductance 23.

As already noted above, the coupling of the battery 20 is different here, namely such that one pole, here the negative pole of the battery 20, is connected directly to the potential tap 16b, while the other pole, here the positive pole, is connected to the center node of the DC voltage - Converter 13 'is connected. The connection to the center node takes place via an inductor, with a capacitance being connected in parallel to the battery 20 and thus forming the DC-DC converter.

The functionality, in particular the functionality of error detection, is explained in part below.

As already explained, the residual current/error voltage detection unit 24 is preferably an all-current sensitive (AC+DC) differential current sensor within the charger. A fault is detected when an insulation fault against ground potential occurs on the DC side. This causes the differential current in the sensor to increase. This signal will evaluated and all power semiconductors 14 'switched off. On the positive side of the DC voltage, the fault current can be interrupted because the two diodes connected in series (D1 in both Fig. 19 and Fig. 10) in the current path can block the current in both directions. On the opposite side, in the exemplary embodiment from FIG. 9 the positive side or side of the potential tap 16a and in the exemplary embodiment from FIG Normal operation is permanently closed. In the event of a fault, this switch 28' or 28" is also opened and the two diodes D2 connected in anti-series can interrupt the fault current again in both directions. If the battery is connected with its positive pole to the positive intermediate circuit voltage, the additional switch can be installed in the positive path.

The DC-DC converter 13 'can be designed with a different topography according to further exemplary embodiments, e.g. B. Flying capacitor technology. According to exemplary embodiments, the decisive factor is the arrangement of the diodes D1 and D2, which are provided in the corresponding DC-DC converter 13 'and the rectifier 12'.

The “high speed circuit breaker” described in [2] is implemented in this case by combining the all-current sensitive (AC+DC) differential current sensor in combination with a switch of the DC-DC converter and an additional switch.

In this respect, exemplary embodiments enable DC residual currents to be switched off quickly by using an all-current sensitive differential current sensor in combination with a DC-DC converter and an additional semiconductor switch (if already known, with the restriction to non-insulating battery chargers).

According to exemplary embodiments, the switching off process is carried out by a controller. The method includes the step of executing a shutdown sequence as already explained above.

According to exemplary embodiments, a DC-DC converter 13 can be provided on the DC voltage side (see FIG. 11). Especially with an implementation By adjusting a step-down converter or step-up converter, an additional switch of the converter 13, here in this exemplary embodiment the additional switch 13a ', can be opened by the switch-off sequence.

According to exemplary embodiments, the first potential tap 16a and the second potential tap 16b can each have an additional switch 28, 28 ', 28 ".

Although some aspects have been described in connection with a device, it is understood that these aspects also represent a description of the corresponding method, so that a block or a component of a device is also to be understood as a corresponding method step or as a feature of a method step. Similarly, aspects described in connection with or as a method step also represent a description of a corresponding block or detail or feature of a corresponding device. Some or all of the method steps may be performed by a hardware apparatus (or using a hardware device). Apparatus), such as a microprocessor, a programmable computer or an electronic circuit. In some embodiments, some or more of the key process steps may be performed by such apparatus.

Depending on particular implementation requirements, embodiments of the invention may be implemented in hardware or in software. The implementation may be using a digital storage medium such as a floppy disk, a DVD, a Blu-ray Disc, a CD, a ROM, a PROM, an EPROM, an EEPROM or a FLASH memory, a hard drive or other magnetic or optical memory are carried out on which electronically readable control signals are stored, which can interact with a programmable computer system in such a way that the respective method is carried out. Therefore, the digital storage medium can be computer readable.

Some embodiments according to the invention thus include a data carrier that has electronically readable control signals that are capable of interacting with a programmable computer system such that one of the methods described herein is carried out. In general, embodiments of the present invention may be implemented as a computer program product with a program code, the program code being effective to perform one of the methods when the computer program product runs on a computer.

The program code can, for example, also be stored on a machine-readable medium.

Other embodiments include the computer program for performing one of the methods described herein, the computer program being stored on a machine-readable medium. In other words, an exemplary embodiment of the method according to the invention is therefore a computer program that has a program code for carrying out one of the methods described herein when the computer program runs on a computer.

A further exemplary embodiment of the method according to the invention is therefore a data carrier (or a digital storage medium or a computer-readable medium) on which the computer program for carrying out one of the methods described herein is recorded.

A further exemplary embodiment of the method according to the invention is therefore a data stream or a sequence of signals which represents the computer program for carrying out one of the methods described herein. The data stream or the sequence of signals can, for example, be configured to be transferred via a data communication connection, for example via the Internet.

Another embodiment includes a processing device, such as a computer or a programmable logic device, configured or adapted to perform one of the methods described herein.

Another embodiment includes a computer on which the computer program for performing one of the methods described herein is installed. A further embodiment according to the invention includes a device or system designed to transmit a computer program to a receiver for carrying out at least one of the methods described herein. The transmission can take place electronically or optically, for example. The recipient may be, for example, a computer, a mobile device, a storage device or a similar device. The device or system can, for example, comprise a file server for transmitting the computer program to the recipient.

In some embodiments, a programmable logic device (e.g., a field programmable gate array, an FPGA) may be used to perform some or all of the functionality of the methods described herein. In some embodiments, a field programmable gate array may cooperate with a microprocessor to perform any of the methods described herein. Generally, in some embodiments, the methods are performed by any hardware device. This can be universally applicable hardware such as a computer processor (CPU) or hardware specific to the method, such as an ASIC.

The embodiments described above are merely illustrative of the principles of the present invention. It will be understood that modifications and variations of the arrangements and details described herein will occur to others skilled in the art. Therefore, it is intended that the invention be limited only by the scope of the following claims and not by the specific details presented from the description and explanation of the exemplary embodiments herein.

Source reference

[1] A contribution to modular and highly compact insulating fast chargers for electric vehicles, Jens Schmenger, doctoral thesis, The Technical Faculty of the Friedrich-Alexander-University Erlangen-Nuremberg, 07.2020

[2] Semiconductor Fuse Applications Guide, Mersen (formerly Ferraz Shawmut), January 2002

Claims

Claims Electrical circuit (10, 10', 10"), with the following features: a power converter circuit (12, 12', 13'), which is arranged between a first potential tap (16a) and a second potential tap (16b) and several Switch (14), wherein a battery (20) can be coupled via the first (16a) and/or the second potential tap (16b), the first and/or the second potential tap (16b) having an additional switch (28, 28'). , 28"); a voltage connection (22) connected to the power converter circuit (12, 12', 13'); a fault current/fault voltage detection unit (24), which is coupled to the voltage connection (22) and is designed to detect a fault current or a fault voltage; a controller (26) which is designed to carry out a switch-off sequence in the event of a fault current or fault voltage detected by the fault current/or fault voltage detection unit (24), according to which the additional switch (28, 28', 28") of the first and / or the second potential tap (16b) and at least one of the switches of the converter circuit (12, 12', 13') is opened. Electrical circuit according to claim 1, wherein the voltage connection (22) is arranged on the input side; and/or wherein the voltage connection (22) is a single-phase or three-phase AC voltage connection (22); and/or wherein the voltage connection (22) is connected to a center tap of half bridges of the power converter circuit (12, 12', 13'). Electrical circuit according to one of the preceding claims, wherein all switches of the power converter circuit (12, 12', 13') are opened during the shutdown sequence. Electrical circuit (10, 10', 10") according to one of the preceding claims, wherein the fault current/fault voltage detection unit (24) has a direct current detector and/or a type A RCD, a type B RCD or a type RCD B+. Electrical circuit (10, 10', 10") according to one of the preceding claims, wherein an inductance is provided per phase between the fault current/fault voltage detection unit (24) and the power converter circuit (12, 12', 13'). Electrical circuit (10, 10', 10") according to one of the preceding claims, wherein the power converter circuit (12, 12', 13') has a rectifier and/or a DC-DC converter; or wherein the power converter circuit (12, 12', 13') has a rectifier and a DC-DC converter; and wherein the additional switch (28, 28', 28”) is arranged between the rectifier and the DC-DC converter. Electrical circuit (10, 10', 10") according to one of the preceding claims, wherein a DC-DC converter and/or a DC-DC converter with a center tap is provided between the first and second potential taps (16b); or wherein a DC-DC converter and/or a DC-DC converter with a center tap is provided between the first and second potential taps (16b); wherein a switch of the DC-DC converter, which is opposite the additional switch, is controlled to open by the switch-off sequence. Electrical circuit (10, 10', 10") according to claim 7, wherein the battery (20) on the side of the first potential tap (16a) is connected to a first pole (22a, 22b, 22c) of the battery with the first potential tap (16a). is, wherein the second pole (22a, 22b, 22c) of the battery (20) is connected to the center tap of the DC-DC converter.

9. Electrical circuit (10, 10 ', 10") according to claim 7, wherein the battery (20) on the side of the second potential tap (16b) is connected to the second pole (22a, 22b, 22c) with the second potential tap (16b). is or wherein a first pole (22a, 22b, 22c) of the battery (20) is connected to the center tap of the DC-DC converter.

10. Electrical circuit (10, 10', 10") according to one of the preceding claims, wherein the power converter circuit (12, 12', 13') has a B4 topology or B6 topology.

11. Electrical circuit (10, 10', 10") according to one of the preceding claims, wherein the at least one switch of the power converter circuit (12, 12', 13') and/or the additional switch (28, 28', 28") is implemented as a parallel connection of an active element with a diode.

12. Electrical circuit (10, 10', 10") according to claim 11, wherein the diode associated with the additional switch (28, 28', 28") has the diodes associated with the power converter circuit (12, 12', 13'). Sides of the respective first or second potential tap (16b) are opposite.

13. Battery charger or non-insulating battery charger or rectifier, non-isolated rectifier, inverter, non-isolated inverter comprising a circuit (10, 10 ', 10") according to one of the preceding claims.

14. A method for operating a circuit (10, 10', 10") according to one of claims 1 to 12 with the step of executing a shutdown sequence in the event of a fault current or fault voltage detected by the fault current/fault voltage detection unit (24), wherein the additional switch (28, 28', 28") of the first and/or the second potential tap (16b) and at least one of the switches of the power converter circuit (12, 12', 13') are opened in accordance with the switch-off sequence.

15. Computer program for carrying out the method according to claim 14, if the program runs on a controller (26) of an electrical circuit (10, 10 ', 10") according to one of claims 1 to 12.