Method for controlling an on-board charger of a motor vehicle, and controller

Abstract

The invention relates to a method for controlling an on-board charger (OBC) of a motor vehicle, wherein the on-board charger (OBC) has a configuration circuit (4), a switchable power factor correction filter (5) and an intermediate circuit capacitor, and - the configuration circuit (4) can be switched to carry out charging processes with different AC voltage charging stations (AC) in such a way that the switchable power factor correction filter (5) can be connected to different combinations of charging phases (L1, L2, L3); - the intermediate circuit capacitor (7) is charged in a respective charging process by a charging current coming from the switchable power factor correction filter (7) and wherein the method has the following steps: - a. determining a situation that the intermediate circuit capacitor (7) is to be discharged; and - b. switching the on-board charger (OBC) in such a way that the intermediate circuit capacitor (7) is discharged via the configuration circuit (4).

Description

[0001] 202401008

[0002] 1

[0003] Description

[0004] Method for controlling an on-board charging device of a motor vehicle and control unit

[0005] The invention relates to a method for controlling an on-board charging device of a motor vehicle and a control unit configured to execute the method. The invention further relates to an on-board charging system, a computer program, and a computer-readable medium.

[0006] In the state of the art, on-board charging devices are generally known and are used in fully electric or hybrid motor vehicles to charge an electrical energy storage device via an externally connected AC charging station.

[0007] Common on-board charging devices have a DC link capacitor located between the output of an inverter and the input of a DC-DC converter. This DC link capacitor couples the intermediate circuit between the inverter and the DC-DC converter, ensuring a stable voltage drop across the circuit.

[0008] The intermediate circuit capacitor has a considerable capacitance and stores a significant amount of electrical energy, which poses a safety risk in an emergency situation involving an uncontrolled discharge of the capacitor. This emergency situation arises particularly when the insulation between the AC and DC sections breaks.

[0009] To ensure controlled discharge of the DC link capacitor in the aforementioned emergency situation, the on-board charging device has a dedicated discharge circuit specifically designed and controlled for this emergency scenario. This discharge circuit is essentially intended for a single, specific situation—one that often never occurs—and incurs additional costs. These circumstances are undesirable. 202401008

[0010] 2

[0011] Against this background, the object of the invention is to provide a simplified and improved discharge method for an intermediate circuit capacitor of an on-board charging device. At the very least, the object of the invention is to provide an alternative to the prior art.

[0012] The problem is solved by the features of the independent patent claims. Advantageous embodiments are characterized in the dependent claims.

[0013] According to the first and second aspects, the problem is solved by a method and a corresponding control unit for controlling an on-board charging device of a motor vehicle. The on-board charging device comprises a configuration circuit, a switchable power factor correction filter, and a DC link capacitor. In particular, the switchable power factor correction filter is connected downstream of the configuration circuit, and the DC link capacitor is connected downstream of the power factor correction filter.

[0014] The configuration circuit is switchable for charging processes with different AC charging stations, allowing the switchable power factor correction filter to be connected to different combinations of charging phases. The DC link capacitor is charged by a charging current from the switchable power factor correction filter during each charging process.

[0015] The process includes the following steps:

[0016] - a. Determining a situation where the intermediate circuit capacitor needs to be discharged; and

[0017] - b. Switching the on-board charging device in such a way that a discharge process of the intermediate circuit capacitor takes place via the configuration circuit.

[0018] The configuration circuit includes a variety of charging phases, in particular three charging phases, and is connected to a charging socket into which a charging plug of the AC charging station is inserted during each charging process.

[0019] Depending on the configuration of the AC charging station – for example, country-specific – the charging plug applies an AC voltage to one or more of the charging phases. For example, there are 202401008

[0020] 3

[0021] AC charging stations that perform the charging process in single-phase or three-phase mode.

[0022] The configuration circuit is set up to connect the charging phases in such a way that the on-board charging device meets the requirements of the AC charging station.

[0023] The configuration circuit is designed to provide various combinations of charging phases for the switchable power factor correction filter.

[0024] The switchable power factor correction filter is actively designed and configured to perform a rectifier function. The switchable power factor correction filter is configured to convert a single-phase or multi-phase AC voltage applied to one AC input of the power factor correction filter into a DC voltage and provide this DC voltage at another DC input of the power factor correction filter.

[0025] In particular, the switchable power factor correction filter is designed to provide a rectified charging current at its DC voltage terminal in a charging mode.

[0026] The rectified charging current can be used to charge the intermediate circuit capacitor.

[0027] The on-board charging device may also include a DC / DC converter located downstream of the intermediate circuit capacitor.

[0028] The situations identified in step a. correspond to those in which an emergency situation occurs, for example, an insulation break is detected, particularly when the on-board charging device is operating in a vehicle-to-load (V2L) mode. Alternatively, the detected situation may also consist of the detection that the charging plug of the AC charging station has been / is being disconnected and / or that a plug of an AC load that has drawn power from a high-voltage battery of the vehicle has been / is being disconnected. This allows the 202401008 to be detected even during and after V2L operation.

[0029] 4

[0030] The on-board charging device must comply with the standardized contact protection for persons.

[0031] The discharge current of the DC link capacitor flows through the configuration circuit, and thus through a circuit section that is also essential for charging. Therefore, the dual function of the configuration circuit reduces the cost and effort required for a dedicated discharge circuit.

[0032] In at least one advantageous embodiment according to the first and second aspects, the power factor correction filter comprises a plurality of switches, wherein the switchable power factor correction filter is configured to convert an alternating voltage supplied by the configuration circuit into a direct voltage in the respective charging process in order to supply the charging current to the intermediate circuit capacitor.

[0033] In at least one advantageous embodiment according to the first and second aspects, the on-board charging device comprises at least one short-circuitable pre-charge resistor, through which the DC link capacitor is charged after the start of the respective charging process until a certain state of charge is reached, and which is then short-circuited. In step b., the on-board charging device is connected such that the discharge process of the DC link capacitor takes place via the configuration circuit and at least via some of the switches of the power factor correction filter and / or the pre-charge resistor.

[0034] This design of the process allows the discharge process to take place via additional circuit components that are also involved in the charging process and perform functions there. The cost and complexity of the on-board charging device can therefore be further reduced.

[0035] The pre-charge resistor can be arranged between the power factor correction filter and the DC link capacitor, or a short-circuitable pre-charge resistor can be arranged in each of the charging phases. A short-circuitable pre-charge resistor is understood to be, in particular, a pre-charge resistor to which a switch is connected in parallel for bypassing the pre-charge resistor, or in which the switch is located in a 202401008

[0036] 5

[0037] A branch is arranged parallel to a branch in which the pre-charging resistor is located.

[0038] Preferably in step b. the on-board charging device is switched in such a way that the discharge process of the intermediate circuit capacitor takes place exclusively via electronic circuit components, in particular the configuration circuit, the power factor correction filter and the pre-charge resistor(s), which are also involved at least temporarily in the charging of the DC voltage storage.

[0039] In at least one advantageous embodiment, the power factor correction filter is bidirectional. Optionally, the on-board charging device, which is controlled by the control unit, can also be bidirectional. It can thus be operated in two ways: firstly, to charge the DC battery when an AC charging station is connected, and secondly, to supply power to a load connected to the charging socket. The latter is referred to as "vehicle-to-load (V2L)."

[0040] According to a third aspect, the task is solved by an on-board charging system comprising an on-board charging device and a control unit as described in the second aspect. The on-board charging device includes a configuration circuit, a switchable power factor correction filter, and a DC link capacitor. The configuration circuit is switchable to allow charging processes with different AC charging stations, such that the switchable power factor correction filter can be connected to different combinations of charging phases, and the DC link capacitor is charged by a charging current from the switchable power factor correction filter during each charging process.

[0041] According to a fourth aspect, the above-mentioned task is solved by a computer program comprising commands which, when the program is executed by a control computer of an on-board charging device, cause the control computer to execute the procedure according to the first aspect.

[0042] The control computer has a processor and program memory. Alternatively, the program memory can be assigned to the control computer. The processor can be a central processing unit (CPU). 202401008

[0043] 6. The processor can be a general-purpose processor, a microprocessor, a microcontroller, or a digital signal processor (DSP).

[0044] The feature “switching the on-board charging device in such a manner” is to be understood as meaning that the control computer, by outputting control signals, activates the appropriate switches of the on-board charging device so that the discharge of the intermediate circuit capacitor takes place according to the other specified features.

[0045] According to a fifth aspect, the above-mentioned task is solved by a computer-readable medium containing instructions which, when executed by a control computer of an on-board charging device, cause the control computer to execute the procedure according to the first aspect.

[0046] The computer program can be stored on a computer-readable storage medium, in particular in non-volatile memory.

[0047] Optional variations of the first and second aspects can also be present in the third, fourth, and fifth aspects and have corresponding effects.

[0048] Further advantageous embodiments are disclosed in the appended claims and in the following description of exemplary embodiments with reference to the appended figures. In the figures, the same reference numerals are used for elements with essentially the same function; however, these elements need not be identical in every detail.

[0049] Figure 1 shows an on-board charging device and schematically a control unit according to the invention, which controls the on-board charging device according to the method according to the invention;

[0050] Figure 2 shows a variant of the on-board charging device controlled by the method according to the invention, wherein in this variant the pre-charge resistor shown in Figure 1 is replaced by three pre-charge resistors located in charging phases; and 202401008

[0051] 7

[0052] Figure 3 shows a further variant of the on-board charging device controlled by the method according to the invention, wherein configuration switches of a configuration circuit are connected in relation to Figures 1 and 2 in such a way that they contact and include a neutral conductor.

[0053] Figure 1 shows a control unit 1 according to the invention, which controls an on-board charging device (OBC) according to a method according to the invention.

[0054] To better understand the invention, the structure of the on-board charging device (OBC) will first be explained.

[0055] The control unit 1 and the on-board charging device (OBC) are designed for installation in a motor vehicle, such as a fully electric or hybrid vehicle. The on-board charging device (OBC) serves to recharge a DC electrical storage device, in particular battery 2, after it has been discharged.

[0056] The accumulator 2 shown is in particular a high-voltage accumulator 2 which supplies an electric drive unit of the motor vehicle and preferably an on-board network of the motor vehicle with electrical energy.

[0057] The on-board charging device is, as intended, located between the battery 2 and an AC charging station, which supplies the electrical energy required for charging. The on-board charging device is connected to a charging socket 3 on one side and to the battery 2 on the other.

[0058] The on-board charging device (OBC), controlled by the control unit 1, is bidirectional. It can be operated in two ways: firstly, to charge the DC battery 2 when an AC charging station is connected, and secondly, to supply a load connected to the charging socket 3. The latter is referred to as "vehicle-to-load".

[0059] The dashed line shown in Figure 1 schematically indicates the outer surface of the vehicle. The charging socket 3 is located on the outer surface of the vehicle, so that a (not shown) charging plug of the 202401008

[0060] 8

[0061] The AC charging station can be inserted into the charging socket 3 to charge the motor vehicle or the battery 2 and can be contacted with the on-board charging device.

[0062] The on-board charging device OBC includes as components a configuration circuit 4, a power factor correction filter 5 with six switches, such as transistors, a pre-charge resistor 6, an intermediate circuit capacitor 7 and a DC voltage converter 8.

[0063] The power factor correction filter 5 is preferably designed to be bidirectional and functions as an inverter in the opposite direction, the "vehicle-to-load" mode.

[0064] For example, the control unit 1 is configured to control the components during a charging process and thus to carry out a charging procedure to charge the battery 2.

[0065] The control unit 1 is configured to carry out a control method according to the invention in order to discharge the intermediate circuit capacitor 7 in certain situations. The corresponding steps of the control method according to the invention are explained below.

[0066] The configuration circuit 4 includes three charging phases L1, L2 and L3 as well as a neutral conductor N which is irrelevant in Figure 1.

[0067] The charging network for motor vehicles installed in public spaces includes various types of AC charging stations, which apply an alternating voltage generated for charging the accumulator 2 to different charging phases L1, L2, L3.

[0068] For example, some AC charging stations charge battery 2 via one of the charging phases L1, L2, or L3, while others charge battery 2 via all three charging phases L1, L2, and L3. The different types of AC charging stations are, for example, country-specific and are due to differences in the public power grids of different countries.

[0069] In order for the various AC charging stations to charge the vehicle equipped with the on-board charging device (OBC), 202401008

[0070] 9 The configuration circuit 4 controlled by the control unit 1 is provided. This includes a configuration switch 40, which is configured to connect the charging phase L1 with the charging phase L2, so that an AC voltage phase applied via the charging socket 3 takes over the single-phase charging of the accumulator 2.

[0071] If, however, the control unit 1 has switched the configuration switch 40, the charging phase L1 and the charging phase L2 are separated from each other, so that the charging of the battery 2 can be taken over by an AC charging station which uses three AC phases (three-phase current) to charge the battery 2.

[0072] In addition to the configuration switch 40, the configuration circuit 4 preferably includes coils or inductors 41, which, however, are not essential for the invention. These coils have high resistance and only a few pH values.

[0073] The control unit 1 is specifically designed to recognize the charging procedure required by the AC charging station or the alternating voltages applied to the charging phases L1, L2, L3 by the charging plug and to make the corresponding position of the configuration switch 40.

[0074] The power factor correction filter 5, controlled by the control unit 1, includes an active rectifier and contains six switches, such as transistors.

[0075] In addition to rectifying the AC voltage(s) supplied by the AC charging station, the power factor correction filter 5 preferably also performs power factor correction (PFC). This PFC correction stabilizes the generated DC voltage at the intermediate circuit capacitor 7. Preferably, the power factor correction filter 5 is a 6-switch boost PFC rectifier.

[0076] The power correction factor filter 5 has a bridge configuration with three bridge branches 50, 51, 52, each containing a high-side switch 50a, 51a, 52a and a low-side switch 50b, 51b, 52b. 202401008

[0077] 10

[0078] The charging phases L1, L2, L3 are each connected to a corresponding bridge branch 50, 51, 52 between the corresponding high-side switch 50a, 51a, 52a and the corresponding low-side switch 50b, 51b, 52b.

[0079] During the charging process, the control unit 1 controls the power factor correction filter 5 and the respective switches in such a way that the alternating voltage supplied by the AC charging station is rectified and a rectified charging current L is generated, which charges the intermediate circuit capacitor 7 shown.

[0080] When the charging process is initiated, the rectified charging current k initially flows through the pre-charge resistor 6 shown.

[0081] This pre-charge resistor 6 protects the intermediate circuit capacitor 7 from an excessively high or undefined charging current L and potential damage.

[0082] The pre-charge resistor 6 can be short-circuited via a bypass 60 shown, in which a bypass switch 61 is provided. The bypass switch 61 is, for example, a transistor, wherein the bypass switch 61 is open when the charging process is initiated and the charging current L flows through the pre-charge resistor 6.

[0083] When the intermediate circuit capacitor 7 is sufficiently charged, the control unit 1 closes the bypass switch 61, so that the pre-charge resistor 6 is short-circuited and the charging current L flows via the bypass 60.

[0084] The intermediate circuit capacitor 7 has a relatively large capacitance and serves to stabilize and couple the output of the power factor correction filter 5 with the input of the DC voltage converter 8.

[0085] The DC voltage converter 8 converts the DC voltage supplied by the power factor correction filter 5 via the intermediate circuit capacitor 7 into a charging DC voltage intended for charging the accumulator 2.

[0086] The situations mentioned earlier may occur in which the intermediate circuit capacitor 6 needs to be discharged. 202401008

[0087] 11

[0088] Examples of such situations include disconnecting the charging plug and / or emergency situations such as crashes and / or short circuits in "vehicle-to-load" mode.

[0089] The discharge of the intermediate circuit capacitor 7 is carried out in these situations to prevent the intermediate circuit capacitor 7 from posing a safety risk due to its capacity and the stored energy.

[0090] The method according to the invention relates to these situations and provides a method for controlling the on-board charging device (OBC), wherein the control unit 1 according to the invention is configured to carry out the method according to the invention.

[0091] The control unit 1 is configured to determine that the intermediate circuit capacitor 7 needs to be discharged (step a.). This determination can be based, for example, on the control unit 1 receiving a corresponding instruction from higher-level safety devices, or on the need for discharge being determined based on sensor data.

[0092] Step b of the inventive method then follows. In this step b, the control unit 1 activates the configuration circuit 4 and ensures that the configuration switch 40 is in the position shown in Figure 1.

[0093] In addition, the control unit 1 controls the power factor correction filter 5 in such a way that the high-side switch 51 a of the second bridge branch and the low-side switch 50b of the first bridge branch are closed.

[0094] The intermediate circuit capacitor 7 is thus short-circuited by the switch positions described and discharges according to the invention via the configuration circuit 4.

[0095] Additionally, the control unit 1 can open the bypass switch 61, which results in the discharge current flowing through the pre-charge resistor and thus the discharge current is not undefined or is limited accordingly.

[0096] It should be emphasized that the discharge of the intermediate circuit capacitor takes place exclusively via components and circuit parts that are also used in the 202401008

[0097] 12

[0098] Charging is involved, at least temporarily. Therefore, it is not necessary to provide dedicated circuit sections and components for discharging.

[0099] Figures 2 and 3 show variants of the on-board charging device that controls the control unit 1 according to the method according to the invention.

[0100] The on-board charging device (OBC) according to Figure 2 differs from that of Figure 1 in that the pre-charge resistor is not located between the intermediate circuit capacitor 7 and the power factor correction filter 5. Instead, a separate pre-charge resistor 6a, 6b, 6c is provided in each of the charging phases L1, L2, L3.

[0101] Each of these pre-charge resistors 6a, 6b, 6c can be short-circuited via a correspondingly assigned bypass 60a, 60b, 60c, in which a corresponding bypass switch 61a, 61b, 61c is arranged. The control unit 1 is responsible for actuating the bypass switches 61a, 61b, 61c.

[0102] When the charging of the DC battery 2 is initiated, the bypass switches 61a, 61b, 61c are open, insofar as the corresponding charging phase is involved, until the intermediate circuit capacitor 7 is sufficiently charged. The control unit 1 then closes the bypass switches 61a, 61b, 61c.

[0103] In step b. mentioned with reference to Figure 1, the control unit 1 controls the high-side switch 51 a of the second bridge branch 51 and the low-side switch 50b of the first bridge branch 50, as explained with reference to Figure 1.

[0104] The intermediate circuit capacitor 7 discharges as shown in Figure 1 in these switch positions via the interconnected charging phases L1 and L2 and the respective closed bridge branches 50, 51.

[0105] Furthermore, the control unit 1 can open or close the bypass switch 61a and / or the bypass switch 61b, thus reducing the overall resistance. In this respect, the control unit 1 can control the magnitude of the discharge current with which the intermediate circuit capacitor 7 discharges, and thus the discharge rate. 202401008

[0106] 13

[0107] Figure 3 shows another variant of the on-board charging device OBC, which differs from Figures 1 and 2 in the design of the configuration circuit 4.

[0108] The configuration circuit from Figure 3 includes two configuration switches 42, 43, which are arranged in the charging phases L2 and L3.

[0109] The configuration switches 42, 43 can each be switched in such a way that the corresponding charging phases L2, L3 are each connected to the neutral conductor N.

[0110] In the position of the configuration switches 42, 43 shown in Figure 3, the charging process of the accumulator 2 takes place in a single-phase manner. If, however, the configuration switches 42, 43 are in their other position, the accumulator 2 can be charged in a three-phase manner by the AC charging station.

[0111] In step b. of the method according to the invention, the control unit 1 ensures that the configuration switches 42, 43 assume the position shown in Figure 3.

[0112] Regarding the control of the power factor correction filter 5 and the pre-charge resistor 6, reference is made to the explanations in Figure 1.

[0113] Figure 3 merely illustrates that, to perform the discharge, it is not the low-side switch of the first bridge branch 50, but rather the low-side switch 52b of the third bridge branch 52 that can be closed. It is only necessary that one of the high-side switches below one of the low-side switches is closed for the discharge to occur.

[0114] In particular, the power factor correction filter 5 is configured in hardware such that both switches, the high-side switch and the low-side switch, of a bridge branch cannot be closed simultaneously. This configuration of the power factor correction filter 5 is for safety reasons and prevents unintended short circuits. For this reason, it is necessary to close the high-side and low-side switches of different bridge branches.

[0115] The control method according to the invention is implemented in particular by software in the control unit 1.

Claims

202401008 14 Patent claims 1. Method for controlling an on-board charging device (OBC) of a motor vehicle, wherein the on-board charging device (OBC) comprises a configuration circuit (4), a switchable power factor correction filter (5) and an intermediate circuit capacitor, and - the configuration circuit (4) for carrying out charging processes with different alternating current charging stations (AC) is switchable in such a way that the switchable power factor correction filter (5) can be connected with different combinations of charging phases (L1 , L2, L3); - the intermediate circuit capacitor (7) is charged in a respective charging process by a charging current coming from the switchable power factor correction filter (7); and wherein the method comprises the following steps: - a. Determining a situation in which the intermediate circuit capacitor (7) needs to be discharged; and - b. Switching the on-board charging device (OBC) such that a discharge process of the intermediate circuit capacitor (7) takes place via the configuration circuit (4).

2. The method of claim 1, wherein the switchable power factor correction filter - has a plurality of switches (50a, b; 51 a,b; 52a, b) and is configured to convert an alternating voltage supplied by the configuration circuit (4) into a direct voltage in the respective charging process in order to supply the charging current to the intermediate circuit capacitor (7); wherein in step b., the on-board charging device (OBC) is switched such that the discharge process of the intermediate circuit capacitor (7) additionally takes place via at least some of the switches (50a, b; 51 a,b; 52a, b) of the power factor correction filter (5).

3. The method of claim 2, wherein the on-board charging device (OBC) further comprises: - a short-circuitable pre-charge resistor (6), via which the intermediate circuit capacitor (7) is charged after the start of the respective charging process until a certain state of charge of the intermediate circuit capacitor is reached and which is then short-circuited; wherein in step b., the on-board charging device (OBC) is switched such that the discharge process of the intermediate circuit capacitor (7) additionally takes place via the pre-charge resistor (6). 202401008 15 4. Method according to one of the preceding claims, wherein the power factor correction filter (5) is bidirectional.

5. Method according to one of the preceding claims, wherein in step b., the on-board charging device (OBC) is switched such that the discharge process of the intermediate circuit capacitor (7) takes place exclusively via electronic circuit components that are also at least temporarily involved in the charging of the DC voltage storage device (2).

6. Method according to any one of the preceding claims 1 to 5, wherein the configuration circuit (4) comprises three charging phases (L1, L2, L3) which are intended to be contacted with the respective AC charging station via a charging socket (3), and at least one configuration switch (40, 42, 43) for switching between the different combinations of charging phases (L1, L2, L3); wherein in step b., the configuration switch (40, 42, 43) is switched such that at least two of the three charging phases (L1, L2, L3) are short-circuited and the discharge process of the DC link capacitor (7) takes place via the short-circuited charging phases (L1, L2, L3).

7. Method according to any one of the preceding claims 1 to 5, wherein the configuration circuit (4) comprises three charging phases (L1, L2, L3) and a neutral conductor (N), which are intended to be contacted with the respective AC charging station (AC) via a charging socket (3), and at least two configuration switches (40, 42, 43) for switching between the different combinations of charging phases (L1, L2, L3); wherein in step b., the two configuration switches (40, 42, 43) are switched such that at least two of the three charging phases (L1, L2, L3) are short-circuited via the neutral conductor (N) and the discharge process of the DC link capacitor (7) takes place via the short-circuited charging phases (L1, L2, L3).

8. A method according to claim 6 or 7, wherein the switchable power factor correction filter (5) has a bridge structure with three bridge branches (50, 51, 52) and the plurality of switches in the bridge branches each form a high-side switch (50a, 51a, 52a) and a low-side switch (50b, 51b, 52b); wherein 202401008 16 in step b., at least one of the high-side switches (50a, 51a, 52a) and one of the low-side switches (50b, 51b, 52b) is closed, wherein the closed high-side switch and the closed low-side switch are arranged in different of the bridge branches (50, 51, 52).

9. Control unit (1) for a motor vehicle, which is configured to control an on-board charging device (OBC) of the motor vehicle, wherein the on-board charging device (OBC) comprises a configuration circuit (4), a switchable power factor correction filter (5) and an intermediate circuit capacitor (7), and the configuration circuit (4) is switchable for carrying out charging operations with different alternating current (AC) charging stations such that the switchable power factor correction filter (5) can be connected to different combinations of charging phases (L1, L2, L3); - the intermediate circuit capacitor (7) is charged in a respective charging process by a charging current coming from the switchable power factor correction filter (5); and the control device is set up: - to receive an instruction that the intermediate circuit capacitor (7) is to be discharged; and - then to control the on-board charging device (OBC) in such a way that a discharge process of the intermediate circuit capacitor (7) takes place via the configuration circuit (4).

10. Control unit (1) according to claim 9, which is configured to perform the method according to any one of claims 2 to 8.

11. Featuring an on-board charging system - an on-board charging device (OBC) comprising a configuration circuit (4), a switchable power factor correction filter (5) and an intermediate circuit capacitor (7), wherein the configuration circuit (4) is switchable for carrying out charging processes with different alternating current (AC) charging stations such that the switchable power factor correction filter (5) can be connected to different combinations of charging phases (L1, L2, L3) and the intermediate circuit capacitor (7) is charged in a respective charging process by a charging current coming from the switchable power factor correction filter (5); and - a control unit according to claim 9 or 10. 202401008 17 12. Computer program comprising instructions which, when executed by a control computer for an on-board charging device, cause the latter to execute the method according to any one of claims 1 to 8.

13. Computer-readable medium comprising instructions which, when executed by a control computer for an on-board charging device, cause the latter to execute the method according to any one of claims 1 to 8.

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