Converter system for transmitting electric power

Abstract

The invention relates to a converter system for transmitting electrical power, a vehicle comprising such a converter system and a method for transmitting electrical power in such a converter system. The converter system comprises a first DC-DC module, a second DC-DC module and a first control unit. The first DC-DC module is connected to a first high-voltage interface of a high-voltage system and to a first low-voltage interface of a low-voltage system. The second DC-DC module is connected to a second high-voltage interface of the high-voltage system and to a second low-voltage interface of the low-voltage system. The first high-voltage interface and the second interface are independent from each other. The first control unit is connected to the first DC-DC module and is configured to supply power by means of the second DC-DC module in case of a malfunction of the first DC-DC module.

Description

Technical Field

[0001] The present invention relates to a converter system for transmitting electricity, a vehicle including such a converter system, and a method for transmitting electricity in such a converter system. Background Technology

[0002] In electric vehicles, various power conversion modules exist, each operating normally under different conditions. For example, the onboard charger converts AC to DC to charge the high-voltage battery, while the traction inverter converts DC to AC to drive the vehicle. In both scenarios, the onboard charger or traction inverter functions correctly. However, to maintain power supply to low-voltage system loads, the DC-DC converter that transfers power from the high-voltage system to the low-voltage system must function correctly in both scenarios.

[0003] DC-DC converters face greater stress than other power conversion modules, making their design more complex. If a DC-DC converter fails during operation, certain vehicle functions powered by the low-voltage system may be at risk, especially when the low-voltage battery is low in charge. Furthermore, the DC-DC converter is off when the vehicle is in the key-off state. In traditional electric vehicles, the low-voltage control unit relies on the low-voltage battery for power. Therefore, if a vehicle is parked for several months, the low-voltage battery will be deeply discharged, potentially causing the vehicle to cease functioning completely. Summary of the Invention

[0004] An improved converter system that allows for a more reliable supply of low-voltage power may be required.

[0005] This problem is addressed by the subject matter of the independent claims of this disclosure, wherein further embodiments are incorporated in the dependent claims. It should be noted that several aspects of this disclosure described below are applicable to converter systems for transmitting electricity, vehicles including such converter systems, and methods for transmitting electricity in such converter systems.

[0006] According to this disclosure, a converter system for transmitting power is proposed. The converter system includes a first DC-DC (direct current to direct current) module, a second DC-DC module, and a first control unit. The first DC-DC module is connected to a first high-voltage interface of a high-voltage system and a first low-voltage interface of a low-voltage system. The second DC-DC module is connected to a second high-voltage interface of the high-voltage system and a second low-voltage interface of the low-voltage system. The first high-voltage interface and the second high-voltage interface are independent of each other. The first control unit is coupled to the first DC-DC module and configured to supply power through the second DC-DC module in the event of a failure of the first DC-DC module.

[0007] The converter system disclosed herein reduces power supply risk even in the event of a single point of failure within the first and second DC-DC modules. By providing power availability on the low-voltage system, the converter system can still operate even in the event of a failure in the first and / or second DC-DC modules. Therefore, the converter system can more effectively maintain the battery system and power supply. Furthermore, a high degree of safety integration can be achieved with the converter system.

[0008] The first DC-DC module and the second DC-DC module are configurable to supply power from a high-voltage system to a low-voltage system and / or from the low-voltage system to the high-voltage system. The high-voltage system can provide 200V or 400V, and the low-voltage system can provide 12V or 48V. However, the input voltage of the high-voltage system can vary depending on its configuration. The first DC-DC module and the second DC-DC module can operate according to load consumption to maximize the efficiency of the converter system. In other words, the first DC-DC module and the second DC-DC module can operate individually or together to provide an efficient power supply.

[0009] The first high-voltage interface and the second high-voltage interface respectively ensure reliable coupling between the first DC-DC module and the high-voltage system, and between the second DC-DC module and the high-voltage system. The high-voltage system may include one or more battery cells. The first high-voltage interface and the second high-voltage interface may be connected to the same battery cell or to different battery cells. The first low-voltage interface and the second low-voltage interface respectively ensure reliable coupling between the first DC-DC module and the low-voltage system, and between the second DC-DC module and the low-voltage system. The first low-voltage interface and the second low-voltage interface may also be connected to the same low-voltage system load or different low-voltage system loads. The low-voltage system load may be a control element for opening doors or windows, starting a motor, steering, or braking, etc.

[0010] The first DC-DC module and the second DC-DC module are connected independently to each of the high-voltage system and the low-voltage system. In other words, the first high-voltage interface and the second high-voltage interface operate independently of each other, and the first low-voltage interface and the second low-voltage interface operate independently of each other. The term "independently" can be understood as the separation of the structure and / or function of the two components. Therefore, the first high-voltage interface and the second high-voltage interface can function independently of each other, and the first low-voltage interface and the second low-voltage interface can function independently of each other.

[0011] The first control unit may include a digital signal processor (DSP) with a dedicated CAN communication interface. The first control unit may be configured to monitor the first DC-DC module and detect whether the first DC-DC module is faulty. The fault may occur within the first DC-DC module and may be a hardware component failure, a software control failure, or a combination of both.

[0012] If the first control unit receives any fault signal from the first DC-DC module, it can disconnect the connection between the first DC-DC module and the first high-voltage interface and / or the connection between the first DC-DC module and the first low-voltage interface. Simultaneously, the first control unit can enable or maintain the operation of the second DC-DC module to reliably transfer power between the high-voltage system and the low-voltage system.

[0013] In one embodiment, the converter system further includes a second control unit separate from the first control unit. The second control unit is connected to the second DC-DC module and configured to transmit power through the first DC-DC module in the event of a failure in the second DC-DC module. The second control unit may also include a digital signal processor (DSP) with a dedicated CAN communication interface. The second control unit may be configured to monitor the second DC-DC module and detect whether the second DC-DC module is faulty.

[0014] If the second control unit receives any fault signal from the second DC-DC module, it can disconnect the connection between the second DC-DC module and the second high-voltage interface and / or the connection between the second DC-DC module and the second low-voltage interface. Simultaneously, the second control unit can enable or maintain the operation of the first DC-DC module to reliably transfer power between the high-voltage system and the low-voltage system. Therefore, even if either the first or second DC-DC module fails, the converter system can ensure reliable power transmission.

[0015] In one embodiment, the first DC-DC module includes a first AC-DC (alternating current to direct current) unit and a first DC-AC (direct current to alternating current) unit, and the second DC-DC module includes a second AC-DC unit and a second DC-AC unit. Each DC-AC unit is connected to each high-voltage interface, and each AC-DC unit is connected to each low-voltage interface. In other words, the first DC-AC unit may be coupled to the first high-voltage interface, and the first AC-DC unit may be coupled to the first low-voltage interface. Furthermore, the second DC-AC unit may be coupled to the second high-voltage interface, and the second AC-DC unit may be coupled to the second low-voltage interface.

[0016] The first AC-DC unit and the first DC-AC unit allow power transfer between the high-voltage system and the low-voltage system via the first DC-DC module. The second AC-DC unit and the second DC-AC unit allow power transfer between the high-voltage system and the low-voltage system via the second DC-DC module. Therefore, independent operation of the first DC-DC module and the second DC-DC module can be ensured.

[0017] In one embodiment, the first DC-DC module further includes a third AC-DC unit, and the second DC-DC module further includes a fourth AC-DC unit. The third and fourth AC-DC units are connected to an AC (alternating current) interface via a power factor correction (PFC) unit and are configured to supply power to the high-voltage system and / or the low-voltage system. In other words, each of the first DC-DC module and the second DC-DC module can be connected to an on-board charger, which provides means and methods for charging the battery system from an external AC power source.

[0018] Therefore, the power factor correction unit can be connected to the external AC power supply on one side. The other side of the PFC unit can be connected to the third AC-DC unit and the fourth AC-DC unit, wherein the third AC-DC unit and the fourth AC-DC unit can operate independently of each other. The PFC unit can be configured to change the output voltage within a predetermined range and to provide DC power to the third AC-DC unit and / or the fourth AC-DC unit during the charging process.

[0019] Therefore, the first AC-DC unit can convert DC power supplied from the third AC-DC unit, and / or the second AC-DC unit can convert DC power supplied from the fourth AC-DC unit, to provide power to the low-voltage system load through each low-voltage interface. Furthermore, the first DC-AC unit can transfer DC power supplied from the third AC-DC unit to the first high-voltage interface, and the second DC-AC unit can transfer DC power supplied from the fourth AC-DC unit to the second high-voltage interface. Thus, independent power transfer through the first DC-DC module and the second DC-DC module can be achieved during charging, ensuring reliable power transfer even if either the first DC-DC module or the second DC-DC module fails.

[0020] In one embodiment, the first DC-AC unit and the second DC-AC unit are configured to supply power from the high-voltage system to the low-voltage system via the first AC-DC unit and the second AC-DC unit, respectively. In other words, the converter system can be configured to transmit power bidirectionally. Therefore, the first DC-AC unit can transfer power from the first high-voltage interface to the first low-voltage interface via the first AC-DC unit, and the second DC-AC unit can transfer power from the second high-voltage interface to the second low-voltage interface via the second AC-DC unit. Thus, the high-voltage system and the low-voltage system can mutually supply power according to their respective voltage system's operating state or charging state to improve efficiency.

[0021] In one embodiment, the first AC-DC unit and the second AC-DC unit are configured to remain on to supply power to each low-voltage interface. In other words, the first AC-DC unit can continuously supply power to the first low-voltage interface, and the second AC-DC unit can continuously supply power to the second low-voltage interface. Therefore, even if the first DC-DC module or the second DC-DC module fails, continuous power supply to the low-voltage system can be achieved through the first low-voltage interface or the second low-voltage system.

[0022] In one embodiment, the first AC-DC unit and the second AC-DC unit are configured to supply power from the low-voltage system to the high-voltage system via the first DC-AC unit and the second DC-AC unit, respectively. During operation, the first AC-DC unit can transfer power from the first low-voltage interface to the first high-voltage interface via the first DC-AC unit, and the second AC-DC unit can transfer power from the second low-voltage interface to the second high-voltage interface via the second DC-AC unit. Therefore, the high-voltage system and the low-voltage system can mutually supply power according to their respective operating or charging states to improve efficiency.

[0023] In one embodiment, the third and fourth AC-DC units are configured to supply power from the high-voltage system to the AC interface. The AC interface may be further coupled to the power grid or any AC load. The converter system can be configured to enable reverse power transfer and supply power from the first and / or second high-voltage system to an external system via the first and / or second DC-DC modules. Therefore, efficient energy use can be achieved.

[0024] In one embodiment, the converter system further includes a first low-power DC-DC unit and a second low-power DC-DC unit configured to transmit power in only one direction. The first low-power DC-DC unit may be connected to the first high-voltage interface on one side and to the first low-voltage interface on the other side. The second low-power DC-DC unit may be connected to the second high-voltage interface on one side and to the second low-voltage interface on the other side. Both the first and second low-power DC-DC units may be low-power isolated DC-DC converters.

[0025] The first low-power DC-DC unit and the second low-power DC-DC unit are configured to transfer power from the high-voltage system to the low-voltage system. Each of the first low-power DC-DC unit and the second low-power DC-DC unit may include an analog controller or a digital signal processor to maintain power supply to the low-voltage system load, such as opening a door or window, starting a motor, etc. Therefore, the low-voltage system load can also operate in emergency situations where the first DC-DC module and the second DC-DC module fail. Thus, a high level of safety integration of the converter system can be achieved.

[0026] According to this disclosure, a vehicle is also provided. The vehicle includes the converter system described above, wherein the vehicle is an electric vehicle. Even if the first DC-DC module or the second DC-DC module fails, the converter system can still allow power transfer between the high-voltage system and the low-voltage system. The first DC-DC module and the second DC-DC module are independently connected to each of the high-voltage system and the low-voltage system. Therefore, reliable power supply to the vehicle can be achieved.

[0027] In one embodiment, the converter system is configured to operate a first and / or a second low-power DC-DC unit in a key-off state. The first and / or second low-power DC-DC unit may be low-power isolated DC-DC converters that can be directly connected to the high-voltage system and the low-voltage system. The first and / or second low-power DC-DC unit may be configured to supply power, particularly to low-voltage system loads (e.g., core vehicle control units, window opening, or door opening).

[0028] If the vehicle remains in parked mode for an extended period, the low-voltage system may be in a deep discharge state, and the vehicle may cease operation completely. The low-power isolated DC-DC converter can be turned on with the vehicle's ignition switch off and supply power to the low-voltage system. Therefore, a predetermined charging state of the low-voltage system can be maintained, and a complete malfunction of the vehicle can be avoided.

[0029] In one embodiment, the converter system is configured to transfer power from a third AC-DC unit to a first AC-DC unit and a first DC-AC unit and / or from a fourth AC-DC unit to a second AC-DC unit and a second DC-AC unit during a charging mode. If the vehicle is in charging mode, the on-board charger can transfer power from the AC interface in the direction of the DC-DC module via the PFC unit. Therefore, the third AC-DC unit can supply power to a first low-voltage interface via the first AC-DC unit and to a first high-voltage interface via the first DC-AC unit. Furthermore, the fourth AC-DC unit can supply power to a second low-voltage interface via the second AC-DC unit and to a second high-voltage interface via the second DC-AC unit.

[0030] In one embodiment, the converter system is configured to transfer power from a high-voltage system to a low-voltage system during driving mode via the first DC-AC unit and the first AC-DC unit and / or the second DC-AC unit and the second AC-DC unit. If the vehicle is in driving mode, the low-voltage system load can be powered from the high-voltage system via the first DC-AC unit and the first AC-DC unit and / or the second DC-AC unit and the second AC-DC unit. Therefore, even if the first DC-DC module or the second DC-DC module fails, a reliable power supply to the low-voltage system load can be ensured. Thus, a high level of safety integration of the converter system can be achieved.

[0031] According to this disclosure, a method for transmitting power in a converter system is also proposed. The method includes the following steps, but not necessarily in this order:

[0032] Connect the first DC-DC module to the first high-voltage interface of the high-voltage system and to the first low-voltage interface of the low-voltage system.

[0033] Connect the second DC-DC module to the second high-voltage interface of the high-voltage system and to the second low-voltage interface of the low-voltage system.

[0034] - Connect the first control unit to the first DC-DC module, and

[0035] - Power is supplied via the second DC-DC module when the first DC-DC module fails.

[0036] The first high-voltage interface and the second high-voltage interface are independent of each other.

[0037] Therefore, the converter system can still operate even if any single point of failure occurs in the first DC-DC module or the second DC-DC module. Furthermore, power supply to the low-voltage system can be ensured even if the first DC-DC module and the second DC-DC module are shut down for extended periods.

[0038] It should be noted that the above embodiments can be combined with each other, regardless of the aspect involved. Therefore, the method can be combined with structural features, and similarly, the system can be combined with the features described above regarding the method.

[0039] These and other aspects of the invention will become apparent and will be illustrated with reference to the embodiments described below. Attached Figure Description

[0040] Exemplary embodiments of the present invention will now be described with reference to the following figures.

[0041] Figure 1 An embodiment of a converter system for transmitting power according to the present disclosure is illustrated schematically and exemplary. Detailed Implementation

[0042] Figure 1 A converter system 1 for transmitting power is shown. The converter system 1 is configured to transmit power from a high-voltage system to a low-voltage system or vice versa. The high-voltage system may have a voltage of 200V or 400V, while the low-voltage system may have a voltage of 12V or 48V. The converter system 1 can be integrated into an electric vehicle for power transmission.

[0043] The converter system 1 includes a first DC-DC module 10 and a second DC-DC module 20. The first DC-DC module 10 includes a first AC-DC unit 14 and a first DC-AC unit 13, and the second DC-DC module 20 includes a second AC-DC unit 24 and a second DC-AC unit 23. The first DC-DC module 10 is connected to a first high-voltage interface 11 of a high-voltage system via the first DC-AC unit 13 and to a first low-voltage interface 12 of a low-voltage system via the first AC-DC unit 14. The second DC-DC module 20 is connected to a second high-voltage interface 21 of the high-voltage system via the DC-AC unit 23 and to a second low-voltage interface 22 via the second AC-DC unit 24. The first AC-DC unit 14 and the second AC-DC unit 24 are configurable to remain on to supply power to each low-voltage interface 12, 22.

[0044] The first high-voltage interface 11 and the second high-voltage interface 21 operate independently of each other, and the first low-voltage interface 12 and the second low-voltage interface 22 operate independently of each other. The high-voltage system may include more than one battery cell. The first high-voltage interface 11 and the second high-voltage interface 21 may be connected to the same battery cell or different battery cells. In contrast, the low-voltage battery system coupled to the first low-voltage interface 12 and the second low-voltage interface 22 may be the same system to ensure the operation of the low-voltage system load in the event of a failure of the first DC-DC module 10 or the second DC-DC module 20.

[0045] The first DC-DC module 10 further includes a third AC-DC unit 15, and the second DC-DC module 20 further includes a fourth AC-DC unit 25. The third AC-DC unit 15 and the fourth AC-DC unit 25 are connected to the AC interface 30 via a power factor correction (PFC) unit 31, and they are configured to supply power to a high-voltage system and / or a low-voltage system. In other words, each of the first DC-DC module 10 and the second DC-DC module 20 is connected to an on-board charger, which provides means and methods for charging the battery system from an external AC power source. Therefore, the power factor correction unit 31 is connected to the AC interface 30 on one side. The other side of the power factor correction unit 31 is connected to the third AC-DC unit 15 and the fourth AC-DC unit 25, wherein the third AC-DC unit 15 and the fourth AC-DC unit 25 operate independently of each other.

[0046] Therefore, the first AC-DC unit 14 converts the DC power supplied from the third AC-DC unit 15 and / or the second AC-DC unit 24 converts the DC power supplied from the fourth AC-DC unit 25 to supply power to the low-voltage system load through each low-voltage interface 12, 22. Furthermore, the first DC-AC unit 13 transfers the DC power supplied from the third AC-DC unit 15 to the first high-voltage interface 11, and the second DC-AC unit 23 transfers the DC power supplied from the fourth AC-DC unit 25 to the second high-voltage interface 21. Thus, independent power transfer through the first DC-DC module 10 and the second DC-DC module 20 can be achieved during the charging process, ensuring reliable power transfer even if either the first DC-DC module 10 or the second DC-DC module 20 fails.

[0047] The converter system 1 is also configured to bidirectionally transfer power from a high-voltage system to a low-voltage system during driving mode via the first DC-AC unit 13 and the first AC-DC unit 14 and / or the second DC-AC unit 23 and the second AC-DC unit 24. The converter system 1 is also configured to supply power from the first high-voltage interface 11 to the AC interface 30 via the third AC-DC unit 15 or from the second high-voltage interface 21 to the AC interface 30 via the fourth AC-DC unit 25. The AC interface 30 may be further coupled to the power grid or any AC load.

[0048] The converter system 1 also includes a first control unit 40 and a second control unit 50. The first control unit 40 and the second control unit 50 include digital signal processors (DSPs) 46 and 56 with dedicated CAN communication interfaces 47 and 57. The first control unit 40 is connected to the first DC-DC module 10 and configured to supply power through the second DC-DC module 20 in the event of a failure of the first DC-DC module 10. The second control unit 50 is disconnected from the first control unit 10. The second control unit 50 is connected to the second DC-DC module 20 and configured to transmit power through the first DC-DC module 10 in the event of a failure of the second DC-DC module 20.

[0049] Therefore, if the first control unit 40 detects a fault in the first DC-DC module 10, the first control unit 40 redirects the power supply through the second DC-DC module 50 instead of the first DC-DC module 10. Conversely, if the second control unit 50 detects a fault in the second DC-DC module 20, the second control unit 50 redirects the power supply through the first DC-DC module 10 instead of the second DC-DC module 20.

[0050] The converter system 1 also includes a first low-power DC-DC unit 18 and a second low-power DC-DC unit 28. The first low-power DC-DC unit 18 is connected to a first high-voltage interface 11 on one side and to a first low-voltage interface 12 on the other side. The second low-power DC-DC unit 28 is connected to a second high-voltage interface 21 on one side and to a second low-voltage interface 22 on the other side. The first low-power DC-DC unit 18 and the second low-power DC-DC unit 28 can be low-power isolated DC-DC converters.

[0051] The first low-power DC-DC unit 18 and the second low-power DC-DC unit 28 are configured to transmit power in only one direction. Therefore, the first low-power DC-DC unit 18 transmits power from the first high-voltage interface 11 to the first low-voltage interface 12, and the second low-power DC-DC unit 28 transmits power from the second high-voltage interface 21 to the second low-voltage interface 22 to supply power to the low-voltage system load. Thus, the low-voltage system load can still operate even in emergency situations where the first DC-DC module 10 and the second DC-DC module 20 fail. Therefore, a high level of safety integration of the converter system can be achieved.

[0052] It should be noted that the embodiments of this disclosure are described with reference to different subjects. Specifically, some embodiments are described with reference to method type claims, while other embodiments are described with reference to device type claims. However, those skilled in the art will understand from the above and below description that, unless otherwise notified, any combination of features relating to different subjects, except for any combination of features belonging to one class of subjects, is also considered to be disclosed with this application. However, all features can be combined together to provide more synergistic effects than the simple sum of these features.

[0053] While this disclosure has been illustrated and described in detail in the accompanying drawings and description, such illustrations and descriptions are to be considered illustrative or exemplary rather than limiting. This disclosure is not limited to the disclosed embodiments. Other variations to the disclosed embodiments will be understood and implemented by those skilled in the art in practicing the claimed disclosure by studying the drawings, the disclosure, and the dependent claims.

[0054] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite words "a" or "an" do not exclude a plural. A single processor or other unit can perform the functions of several items recited in the claims. The fact that certain measures are referenced in mutually different dependent claims does not mean that a combination of these measures cannot be used advantageously. Any reference numerals in the claims should not be construed as limiting the scope.

Claims

1. A converter system (1) for transmitting power, comprising: - First DC-DC module (10). - Second DC-DC module (20) - First control unit (40), and - A second control unit (50) separate from the first control unit (40). The first DC-DC module (10) is connected to the first high-voltage interface (11) of the high-voltage system and the first low-voltage interface (12) of the low-voltage system. The second DC-DC module (20) is connected to the second high-voltage interface (21) of the high-voltage system and the second low-voltage interface (22) of the low-voltage system. The first high-voltage interface (11) and the second high-voltage interface (21) operate independently of each other. The first control unit (40) is connected to the first DC-DC module (10) and configured to disconnect the connection between the first DC-DC module (10) and the first high-voltage interface (11) and / or the first low-voltage interface (12) and supply power through the second DC-DC module (20) when the first DC-DC module (10) fails. The second control unit (50) is connected to the second DC-DC module (20) and configured to disconnect the connection between the second DC-DC module (20) and the second high voltage interface (21) and / or the second low voltage interface (22) and supply power through the first DC-DC module (10) when the second DC-DC module (20) fails.

2. The converter system (1) according to claim 1, wherein the first low voltage interface (12) and the second low voltage interface (22) operate independently of each other.

3. The converter system (1) according to any one of the preceding claims, wherein the first DC-DC module (10) includes a first AC-DC unit (14) and a first DC-AC unit (13), and the second DC-DC module (20) includes a second AC-DC unit (24) and a second DC-AC unit (23), each DC-AC unit (13, 23) being connected to each high-voltage interface, and each AC-DC unit being connected to each low-voltage interface.

4. The converter system (1) according to any one of the preceding claims. The first DC-DC module (10) further includes a third AC-DC unit (15), and the second DC-DC module (20) further includes a fourth AC-DC unit (25), and The third AC-DC unit (15) and the fourth AC-DC unit (25) are connected to the AC interface (30) via the power factor correction unit (31) and are configured to supply power to the high-voltage system and / or to the low-voltage system.

5. The converter system (1) according to claim 3, wherein the first DC-AC unit (13) and the second DC-AC unit (23) are configured to supply power from the high-voltage system to the low-voltage system through the first AC-DC unit (14) and the second AC-DC unit (24), respectively.

6. The converter system (1) according to claim 3, wherein the first AC-DC unit (14) and the second AC-DC unit (24) are configured to remain on to supply power to each low-voltage interface (12, 22).

7. The converter system (1) according to claim 3, wherein the first AC-DC unit (14) and the second AC-DC unit (24) are configured to supply power from the low-voltage system to the high-voltage system through the first DC-AC unit (13) and the second DC-AC unit (23), respectively.

8. The converter system (1) according to claim 4, wherein the third AC-DC unit (15) and the fourth AC-DC unit (25) are configured to supply power from the high-voltage system to the AC interface (30).

9. The converter system (1) according to any one of the preceding claims further includes a first low-power DC-DC unit (18) and a second low-power DC-DC unit (28), the first low-power DC-DC unit (18) and the second low-power DC-DC unit (28) being configured to transmit power in only one direction.

10. A vehicle comprising a converter system (1) according to claim 1 or 2, wherein the vehicle is an electric vehicle.

11. The vehicle according to claim 10, wherein, The converter system (1) further includes a first low-power DC-DC unit (18) and a second low-power DC-DC unit (28), the first low-power DC-DC unit (18) and the second low-power DC-DC unit (28) being configured to transmit power in only one direction, and the converter system (1) being configured to operate the first low-power DC-DC unit (18) and / or the second low-power DC-DC unit (28) in the key switch off state.

12. The vehicle according to any one of claims 10 and 11, wherein, The first DC-DC module (10) includes a first AC-DC unit (14) and a first DC-AC unit (13), and the second DC-DC module (20) includes a second AC-DC unit (24) and a second DC-AC unit (23). Each DC-AC unit (13, 23) is connected to each high-voltage interface, and each AC-DC unit is connected to each low-voltage interface. The first DC-DC module (10) further includes a third AC-DC unit (15), and the second DC-DC module (20) further includes a fourth AC-DC unit (25). The third AC-DC unit (15) and the fourth AC-DC unit (25) are connected to an AC interface (30) via a power factor correction unit (31) and are configured to supply power to the high-voltage system and / or to the low-voltage system. The converter system (1) is configured to transfer power from the third AC-DC unit (15) to the first AC-DC unit (14) and the first DC-AC unit (13) and / or transfer power from the fourth AC-DC unit (25) to the second AC-DC unit (24) and the second DC-AC unit (23) during the charging mode.

13. The vehicle according to any one of claims 10 and 11, wherein, The first DC-DC module (10) includes a first AC-DC unit (14) and a first DC-AC unit (13), and the second DC-DC module (20) includes a second AC-DC unit (24) and a second DC-AC unit (23). Each DC-AC unit (13, 23) is connected to each high-voltage interface, and each AC-DC unit is connected to each low-voltage interface. The converter system (1) is configured to transfer power from a high-voltage system to a low-voltage system during driving mode via the first DC-AC unit (13) and the first AC-DC unit (14) and / or the second DC-AC unit (23) and the second AC-DC unit (24).

14. A method for transmitting power in a converter system (1), comprising the following steps: - Connect the first DC-DC module (10) to the first high-voltage interface (11) of the high-voltage system and to the first low-voltage interface (12) of the low-voltage system. - Connect the second DC-DC module (20) to the second high-voltage interface (21) of the high-voltage system and to the second low-voltage interface (22) of the low-voltage system. The first high-voltage interface (11) and the second high-voltage interface (21) operate independently of each other. - Connect the first control unit (40) to the first DC-DC module (10). The method is characterized by: - Connect the second control unit (50), which is separate from the first control unit (40), to the second DC-DC module (20). - In the event of a failure of the first DC-DC module (10), disconnect the first DC-DC module (10) from the first high-voltage interface (11) and / or the first low-voltage interface (12) and supply power through the second DC-DC module (20), and - In the event of a failure of the second DC-DC module (20), disconnect the connection between the second DC-DC module (20) and the second high voltage interface (21) and / or the second low voltage interface (22) and supply power through the first DC-DC module (10).

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