DC-DC converter for vehicle
The system addresses inefficiencies in electric vehicles by using multiple DC-DC converters with varying power modes and cooling methods to efficiently convert high to low voltage, ensuring reliable power distribution to critical loads in both states, reducing weight and consumption.
Patent Information
- Application Number
- CN202510056054.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-01-15
- Filing Date
- 2025-01-14
- Publication Date
- 2025-07-15
AI Technical Summary
In modern electric vehicles, low-voltage electrical systems directly powered by high-voltage batteries increase vehicle weight and power consumption, and low-voltage vehicle batteries have different load cycles in fully electric or hybrid vehicles, resulting in faster deterioration and failure. At the same time, some electrical components in the off-ignition state need to be continuously powered, and existing DC-DC converters cannot operate efficiently at a wide range of power outputs, especially the redundant power supply requirements for safety-critical loads are not met.
The multi-stage DC-DC converter configuration is adopted, including the first and second DC-DC converters that are efficiently powered in the ignition state, and the third DC-DC converter is low-powered in the ignition state, and redundant power is achieved through the power distribution unit and the main fuse box. Combining active and passive cooling methods, it ensures efficient and robust supply of low DC voltages in different states.
It realizes efficient power supply in ignition and off states, improves the system's failsafety and reliability, reduces vehicle weight and power consumption, extends battery life, and meets the redundant power supply requirements for safety-critical loads.
Smart Images
Figure CN120307887A_ABST
Abstract
Description
Field of the Invention
[0001] The present invention relates to a system for supplying a low DC voltage from a high-voltage battery of a vehicle to the vehicle. Background Art
[0002] Modern electric vehicles such as battery electric vehicles (BEVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and fuel cell electric vehicles (FCEVs) generally include a battery with a relatively high output voltage for powering one or more electric motors of the vehicle. In the case of a BEV or FCEV, the electric motor is the only engine for propelling the vehicle. On the other hand, HEVs and PHEVs include an electric motor in addition to an internal combustion engine. For reasons of efficiency, such electric motors operate at a rather high voltage, for example 400 V, 800 V, or even higher.
[0003] On the other hand, the vehicle includes an electrical system for powering electrical loads such as control units, entertainment systems, navigation systems, driver assistance systems, air conditioners, actuators, seat heating, advanced driver assistance systems (ADAS), and the like. Nowadays, autonomous or semi-autonomous vehicles are becoming increasingly common, which include a plurality of electronic components powered by the electrical system. This electrical system generally has a relatively low voltage, for example 12 V, 24 V, or 48 V.
[0004] Therefore, even vehicles that in principle include an electrical power supply (such as BEVs, HEVs, PHEVs, or FCEVs) also include an additional low-voltage battery for powering the electrical and electronic components of the vehicle. This has several disadvantages. First, the additional battery increases the total weight of the vehicle, which increases fuel and / or power consumption and reduces the range of the vehicle. Second, the low-voltage vehicle battery is designed for the typical load cycles of conventional internal combustion engine vehicles. For fully electric or hybrid vehicles, the load cycles are very different, resulting in faster degradation and failure of the low-voltage battery.
[0005] Therefore, attempts have been made to omit the low-voltage vehicle battery and use the high-voltage traction battery to power the electrical system of the electric or semi-electric vehicle. This requires a DC-DC converter in order to convert the high-voltage output of the battery (for example 400 V) into the low voltage (for example 12 V) required by the electrical system of the vehicle. However, when the vehicle is stationary, some electrical components of the vehicle must also be powered, which are so-called key-off loads. Examples include alarm systems / anti-theft systems, entertainment / infotainment systems, parking heating, and air conditioning. In addition, modern automobiles are usually wirelessly connected, for example via a mobile communication network such as 4G or 5G, even when the engine is turned off. The corresponding connection unit needs to be powered at all times.
[0006] Therefore, the DC-DC converter mentioned above must operate efficiently over a wide range of power output levels to power the vehicle's electrical system in the off state and the key-on state. In addition, some electrical loads may have an Automotive Safety Integrity Level (ASIL) and require certain safety requirements. Depending on the safety level of such loads, some power-consuming devices must be redundantly powered by two low-voltage power rails. SUMMARY OF THE INVENTION
[0007] The present invention addresses these needs through the subject matter of the independent claims. Advantageous embodiments are defined in the dependent claims.
[0008] Accordingly, the present invention relates to a system for supplying a low DC voltage to a vehicle from a high-voltage battery of the vehicle, the system comprising: a first DC-DC converter configured to convert a high DC voltage from a first battery of the vehicle into a low DC voltage; a second DC-DC converter configured to convert a high DC voltage from a second battery of the BEV into a low DC voltage; a third DC-DC converter having a lower output power compared to the first DC-DC converter and the second DC-DC converter, and configured to convert a high DC voltage from a battery of the vehicle into a low DC voltage, wherein the first DC-DC converter is configured to be connected to the first battery, wherein the second DC-DC converter (3b) is configured to be connected to the second battery, and wherein the third DC-DC converter is configured to be connected in series to the first battery and the second battery.
[0009] The present invention is not limited to applications involving two different batteries ("first battery" and "second battery"). Instead, the present invention also covers the case of only a single battery. In this case, the "first battery" may be the first part or section of a single battery, and the "second battery" may be the second part or section of a single battery. In addition, in this case, the term "high-voltage battery" should be understood as a single battery having multiple parts or sections (at least two). For example, a single battery may include a plurality of stacked battery cells and include multiple power outputs. It should be noted that the battery itself is not part of the system according to the present invention.
[0010] In the context of the present invention, a DC-DC converter (direct current to direct current converter) is understood to be an electronic circuit or electromechanical device that converts a direct current (DC) source from one voltage level to another voltage level. Therefore, the first DC-DC converter, the second DC-DC converter, and the third DC-DC converter take the high voltage from the high-voltage battery as input and convert it into a low voltage that is lower compared to the high voltage.
[0011] The first DC-DC converter and the second DC-DC converter can be configured to provide a low DC voltage in the ignition state of the vehicle, and the third DC-DC converter can be configured to provide a low DC voltage in the key-off state of the vehicle. In this way, the first DC-DC converter and the second DC-DC converter can operate in their optimal domain, i.e., the high-power mode, while the third DC-DC converter can also operate in its optimal domain, i.e., the low-power mode. In addition, the first DC-DC converter and the second DC-DC converter can supply power redundantly in the ignition state, which improves the fail-safety and reliability.
[0012] In the context of the present invention, the "key-on state" is understood as the state of the vehicle in which power can be immediately supplied to the main engine of the vehicle, so that the motion state of the vehicle is changed (e.g., the vehicle starts to move, accelerates or decelerates). In the "key-off" state, power cannot be supplied to the main engine, and the vehicle is usually in a parked state. In addition, in the key-on state, electric power is supplied to certain electrical loads, but in the key-off state, electric power is not supplied to these loads. Examples include all systems required for driving, such as actuators, control units, driver assistance systems, etc.
[0013] The first DC-DC converter and the second DC-DC converter can be configured to provide electric power in the ignition state in a high-power mode with active cooling. This improves the efficiency of the system because active cooling is only effective in the ignition state where the power consumption is much higher compared to the key-off state. In the key-off state, the power consumption is usually low, so active cooling is not required. The active cooling of the DC-DC converter can be achieved by liquid cooling, air cooling using a fan, a thermal evaporator, etc. The electric power required for these cooling measures is not needed in the key-off state.
[0014] The third DC-DC converter can be configured to provide electric power in the key-off state with only passive cooling. Passive cooling generally means that no additional equipment is operating for cooling to maintain a low static current. It can include using materials with good heat conduction, vents for heat exchange through (passive) air circulation, cooling fins, etc. These measures do not require additional electric power for cooling in the low-power mode of the third DC-DC converter, which is cost-effective, but also increases the fail-safety and robustness of the system because active cooling components introduce additional failure points.
[0015] The third DC-DC converter can be configured to be directly electrically connected to the battery without any switch therebetween. In this way, the third DC-DC converter can supply power in the off state. On the other hand, the first DC-DC converter and the second DC-DC converter can be connected to the battery downstream of the power switch controlling the motor, since their output voltages are only required in the ignition state and not in the off state. Thus, the first DC-DC converter and the second DC-DC converter can be placed outside the battery.
[0016] A system for supplying a low DC voltage from a high-voltage battery of a vehicle to the vehicle can further include at least one power distribution unit configured to provide the low DC voltage to a plurality of loads, wherein the power distribution unit is electrically connected to the second DC-DC converter and selectively electrically connected to the first DC-DC converter or the third DC-DC converter. The power distribution unit allows the low DC voltage to be distributed to loads within the vehicle. In the off state, the third DC-DC converter supplies power to the power distribution unit, and in the ignition state, the first DC-DC converter and the second DC-DC converter supply power to the power distribution unit. Thus, any load connected to the power distribution unit can be supplied with electrical power in both the off state and the ignition state. Additionally, the first DC-DC converter and the second DC-DC converter can be redundantly powered in the ignition state, which improves robustness and fail-safety. In addition to voltage, the power distribution unit can also distribute data, or aggregate data from sensors and peripherals, and distribute the data to actuators via a corresponding data bus. Thus, the power distribution unit can be a zone controller.
[0017] The system can be configured such that in the ignition state of the vehicle, the first DC-DC converter is electrically connected to the power distribution unit, and in the off state, the third DC-DC converter is electrically connected to the power distribution unit. As described above, this allows electrical power to be permanently supplied to loads connected to the power distribution unit.
[0018] The power distribution unit can be configured to electrically connect each of a plurality of loads to a first DC-DC converter or to a second DC-DC converter or to a third DC-DC converter. Thus, the power distribution unit is connected to two DC-DC converters such that power can still be supplied to safety-critical loads in the event of a failure of one of the DC-DC converters. This is especially the case in the ignition state, in which the power distribution unit can switch between a first DC-DC converter operating in a high-power mode and a second DC-DC converter. Non-safety-critical loads, so-called quality management (QM) loads, can be switched off in the event of a failure of one of the DC-DC converters. Thus, even in the event of a failure of the other DC-DC converter, the fault-free DC-DC converter can operate safely and supply voltage to the safety-critical loads.
[0019] Typically, the system can include more than one power distribution unit. The DC-DC converters can be connected to all the power distribution units in the vehicle. At least, the first DC-DC converter and the second DC-DC converter can be connected to all the power distribution units in the vehicle that supply safety-critical loads. In this way, the fail-safety and robustness are increased. The power distribution units that supply only quality management loads can be connected to one DC-DC converter.
[0020] The power distribution unit can be configured to actively distribute a plurality of loads between a first DC-DC converter and a second DC-DC converter such that the first battery and the second battery are substantially balanced. Battery balancing can increase the available capacity of a plurality of batteries or a single battery having a plurality of parts, sections or cells and can increase the battery life. The batteries can naturally have slightly different capacities and thus can be in different states of charge during charge and discharge cycles. Thus, the balancing takes into account the different capacities and can, for example, draw the highest current from the most charged battery. According to the invention, the balancing can be achieved by distributing the loads between the DC-DC converters, which is a simple and effective way of balancing the batteries.
[0021] The power distribution unit can include at least one switch for separating the quality management loads from the safety-critical loads. The quality management loads can be non-safety-critical loads such as heating, air conditioning and entertainment systems. The power distribution unit can, for example, disconnect the quality management loads in the event of a failure such that power is supplied only to the safety-critical loads.
[0022] A system for supplying a low DC voltage from a high-voltage battery of a vehicle to the vehicle may further include: a first electrical main fuse box (eMFB), electrically connected to both a first DC-DC converter and a third DC-DC converter to selectively supply power to a load via the first DC-DC converter or the third DC-DC converter, and electrically connected to a first power distribution unit and a second power distribution unit; and a second eMFB, electrically connected to a second DC-DC converter, the first power distribution unit, and the second power distribution unit. In this way, the two power distribution units are connected to at least the first DC-DC converter and the second DC-DC converter by means of the respective eMFBs, which increases the fail-safety and robustness.
[0023] The system may further include a switch configured to selectively electrically connect the first DC-DC converter or the third DC-DC converter to the first eMFB. In this way, power is selectively provided by the third DC-DC converter in the off state and by the first DC-DC converter in the on state. A further switch may be part of the eMFB.
[0024] The low DC voltage mentioned here may be a nominal voltage of 60V or less, preferably a nominal voltage of 12V, 24V, or 48V. The low DC voltage is the output voltage of the DC-DC converter. As mentioned above, typical loads in the vehicle (except for the main engine) operate at a voltage of 60V or less.
[0025] The high voltage mentioned here may be a nominal voltage greater than 60V, preferably a nominal voltage of 200V, 400V, 800V, or higher. The high voltage is typically supplied to the main engine to propel the vehicle. The DC-DC converter advantageously converts the high voltage supplied by the battery into a low voltage to feed electrical loads within the vehicle. The system according to the invention allows such loads to be operated in both the on state and the off state, while each DC-DC converter does not operate in its optimal power domain. In addition, safety-critical loads can be operated because the first DC-DC converter and the second DC-DC converter arranged according to the invention provide fail-safety and robustness.
[0026] The high-voltage battery may be adapted to power an electric motor of the vehicle. As mentioned above, the system according to the invention advantageously allows low-voltage loads to be operated from the high voltage of the traction battery in a cost-effective and fail-safe manner. Description of the Drawings
[0027] Possible embodiments of the invention are described in more detail below with reference to the following figures:
[0028] Figure 1 Exemplary embodiments of the invention are illustrated. Detailed implementation manners
[0029] For the sake of simplicity, only a few embodiments will be described below. Those skilled in the art will recognize that the features described with reference to these specific embodiments can be modified and combined in different ways, and individual features can also be omitted. The general explanations in the above sections also apply to the following more detailed explanations.
[0030] Figure 1 An embodiment of a system 1 for supplying a low DC voltage from a high-voltage battery of a vehicle to a vehicle ( Figure 1 not shown in the figure) is illustrated. The system 1 includes: a first DC-DC converter 3a configured to convert a high DC voltage provided by a first battery 2a of the vehicle into a low DC voltage; a second DC-DC converter 3b configured to convert a high DC voltage provided by a second battery 2b of the vehicle into a low DC voltage; and a third DC-DC converter 3c having a lower output power compared to the first DC-DC converter 3a and the second DC-DC converter 3b, and configured to convert a high DC voltage from batteries 3a and 3b of the vehicle into a low DC voltage. The batteries 2a and 2b are traction batteries for supplying power to the main engine of the vehicle. Exemplary vehicles in which the present invention can be implemented include battery electric vehicles (BEVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and fuel cell electric vehicles (FCEVs). The electric motors of such vehicles operate at a relatively high voltage, for example, greater than 60V. Typical voltages include 200V, 400V, 800V, or even higher. Typical batteries for this type of vehicle are based on electrochemical cells (such as lithium-ion batteries) with external connections to supply power to the vehicle.
[0031] The batteries supply electric power to the main engine of the vehicle through outputs 4a and 4b, and the outputs 4a and 4b will be connected to a traction inverter ( Figure 1 not shown in the figure). In addition, corresponding main switches are shown before the outputs 4a and 4b, and these main switches disconnect all loads when the vehicle is turned off or in the parking mode. Therefore, the batteries 2a and 2b are usually inside the battery pack together with the DC-DC converter 3c, while the DC-DC converters 3a and 3b can be located outside the battery pack.
[0032] In Figure 1In [the figure], the batteries 2a and 2b are shown as separate components, namely the first battery 2a and the second battery 2b. However, in other embodiments, the first battery 2a may be the first part or section of a single battery, and the second battery 2b may be the second part or section of a single battery. For example, the first battery 2a may include one or more first battery cells, and the second battery 2b may include one or more second battery cells. In such a case, the term "high-voltage battery" should be understood to mean a single battery having multiple parts or sections (at least two). Additionally, it should be understood that the batteries 2a and 2b are not part of the system 1. Instead, the DC-DC converters 3a and 3b of the system of the present invention are configured to be electrically connected to the batteries 2a and 2b. Thus, the first DC-DC converter 3a is configured to be electrically connected to the first battery 2a, and the second DC-DC converter 3b is configured to be electrically connected to the second battery 2b. The connection can be a direct electrical connection without any switches in between and can be made, for example, via a plug or a clamp.
[0033] In Figure 1 the example, the first DC-DC converter 3a, the second DC-DC converter 3b, and the third DC-DC converter 3c are each implemented as magnetic DC-DC converters. In these DC-DC converters, energy is periodically stored in and released from the magnetic field within an inductor or a transformer. Alternatively, other types of DC-DC converters, such as capacitive or switched-mode DC-DC converters, may be used. The output voltages of the first DC-DC converter 3a, the second DC-DC converter 3b, and the third DC-DC converter 3c are each low voltages that are lower than the high voltage at their inputs. Typically, the low voltage is 60V or less. Generally, the electrical system of a vehicle operates at 12V, 24V, or 48V, and the DC-DC converters 3a, 3b, and 3c may be adapted to supply such voltage levels at their outputs.
[0034] In Figure 1 the example, the first DC-DC converter 3a and the second DC-DC converter 3b are configured to provide a low DC voltage in the ignition state of the vehicle. Typically, the DC-DC converters will be supplied with active cooling during the ignition state because the number and power consumption of the active loads are higher in the ignition state compared to the off state. Active cooling can be achieved, for example, by liquid cooling, air cooling using a fan, a thermal evaporator, etc. In the ignition mode, the DC-DC converters 3a and 3b can provide, for example, up to 3kW of power.
[0035] In the off state, power is provided by the third DC-DC converter 3c, which will typically operate without active cooling and only using passive cooling. Passive cooling can be achieved by using materials with good thermal conductivity, vents for heat exchange through (passive) air circulation, cooling fins, etc. In the off mode, the DC-DC converter 3c can provide, for example, up to 300 W of power.
[0036] Figure 1 The system 1 of an exemplary embodiment also includes two power distribution units 5a and 5b, which are configured to supply a low DC voltage to a plurality of loads ( Figure 1 not shown in the figure). It should be noted that the power distribution unit is optional in the context of the present invention. Additionally, in the context of the present invention, the number of such power distribution units can be different from two, for example, three or more.
[0037] In Figure 1 the exemplary embodiment, the power distribution units 5a and 5b are electrically connected to the second DC-DC converter 3b and selectively connected to the first DC-DC converter 3a or the third DC-DC converter 3c. The power distribution units 5a and 5b distribute the low DC voltage to the loads within the vehicle. As Figure 1 shown in the figure, the power distribution units 5a and 5b are configured to electrically connect each of the plurality of loads to the second DC-DC converter 3b or selectively connect to the first DC-DC converter 3a or the third DC-DC converter 3c. To this end, the first power distribution unit 5a includes corresponding switches 6a, 6b, 6c, and 6d. The second power distribution unit 5b includes corresponding switches 6e, 6f, 6g, and 6h. In other embodiments, the number of switches can be different. Figure 1 The switches in the embodiment of
[0038] are implemented based on field effect transistors (FETs), for example, as power metal oxide semiconductor field effect transistors (MOSFETs).
[0039] In the example, the outputs of the power distribution units 5a and 5b associated with switches 6a, 6b, 6e, and 6f can be connected to safety-critical loads, while the outputs associated with switches 6c, 6d, 6g, and 6h can be connected to quality management loads. More specifically, the outputs associated with switches 6a and 6e can feed a first safety-critical load, and the outputs associated with switches 6b and 6f can feed a second safety-critical load. The safety-critical loads will be connected to two rails such that even in the event of a failure of one of the battery, DC-DC converter, or eMFB, the safety-critical loads will still be powered. In contrast, the quality management (QM) loads are not critical and can be powered off in the event of a failure without causing any damage. Thus, in this example, in the event of a failure of one of the DC-DC converters, switches 6c, 6d, 6g, and 6h can turn off their corresponding QM loads, while switches 6a, 6b, 6e, and 6f turn on, so that power from the remaining fault-free DC-DC converter is supplied to the safety-critical loads.
[0040] The way of feeding the safety-critical loads as described above allows for functional safety up to ASIL D level to be achieved through so-called ASIL B(D) decomposition. In this case, the battery, DC-DC converter, eMBF, and zone controller conform to ASIL B, such that ASIL D compliance is achieved by feeding the safety-critical loads redundantly and independently from two branches.
[0041] In addition, in Figure 1 the example, the loads associated with switches 6a, 6c, 6e, and 6g are "always on" in the sense that in the off state, power is supplied to those switches by the third DC-DC converter, and in the ignition state, power is supplied to those switches by the first DC-DC converter via switch 8 to be explained below. In contrast, the loads associated with switches 6b, 6d, 6f, and 6h are only powered in the ignition state because they are only electrically connected to the second DC-DC converter 3b.
[0042] In Figure 1 the example, two power distribution units 5a and 5b are shown. In other embodiments, the system 1 can include more than two power distribution units. In those embodiments, all DC-DC converters 3a, 3b, and 3c or at least the first DC-DC converter 3a and the second DC-DC converter 3b can be connected to all power distribution units. At least, DC-DC converters 3a and 3b can be connected to all power distribution units supplying safety-critical loads.
[0043] In Figure 1In an exemplary embodiment, the power distribution units 5a and 5b actively distribute a plurality of loads between the first DC-DC converter and the second DC-DC converter such that the first battery 2a and the second battery 2b are substantially balanced. To this end, the switches 6a, 6b, 6c, 6d, 6e, 6f, 6g, and 6h electrically connect a specific load to a specific DC-DC converter to achieve a desired power consumption from a specific battery relative to the power consumption from the other battery.
[0044] In Figure 1 an exemplary embodiment of the system 1, the system 1 further includes a first electrical main fuse box (eMFB) 7a electrically connected to the first DC-DC converter 3a and electrically connected to the third DC-DC converter 3c. At the other end, the eMFB 7a is electrically connected to the first power distribution unit 5a and the second power distribution unit 5b. A switch 8 is arranged between the first DC-DC converter 3a and the third DC-DC converter 3c and the eMFB 7a to selectively connect the first DC-DC converter 3a or the third DC-DC converter 3c to the eMFB 7a according to the state of the vehicle. Thus, in the off state, power is supplied by the third DC-DC converter 3c, which is particularly adapted to operate in a low power mode preferably without active cooling. In the ignition state, on the contrary, power is provided by the first DC-DC converter 3a, which is particularly adapted to operate in a high power mode preferably with active cooling.
[0045] The system 1 further includes a second eMFB 7b electrically connected to the second DC-DC converter 3b. At the other end, the eMFB 7b is electrically connected to the first power distribution unit 5a and the second power distribution unit 5b. The eMFB contains fuses that interrupt the current in case of overcurrent to protect the loads, the DC-DC converters, and the batteries.
Claims
1. A system (1) for supplying a low DC voltage to a vehicle from a high-voltage battery (2a, 2b) of the vehicle, the system (1) comprising: A first DC-DC converter (3a) configured to convert a high DC voltage from a first battery (2a) of the vehicle into a low DC voltage; A second DC-DC converter (3b) configured to convert a high DC voltage from a second battery (2b) of the BEV into a low DC voltage; A third DC-DC converter (3c) having a lower output power compared to the first DC-DC converter (3a) and the second DC-DC converter (3b), and configured to convert a high DC voltage from the batteries (2a, 2b) of the vehicle into the low DC voltage, wherein the first DC-DC converter (3a) is configured to be connected to the first battery (2a), wherein the second DC-DC converter (3b) is configured to be connected to the second battery (2b), and wherein the third DC-DC converter is configured to be connected in series to the first battery (2a) and the second battery (2b).
2. The system (1) according to claim 1, characterized in that, The first DC-DC converter (3a) and the second DC-DC converter (3b) are configured to provide the low DC voltage in an ignition state of the vehicle, and the third DC-DC converter (3c) is configured to provide the low DC voltage in a non-ignition state of the vehicle.
3. The system (1) according to any one of claims 1-2, characterized in that The first DC-DC converter (3a) and the second DC-DC converter (3b) are configured to provide electric power in a high-power mode with active cooling in the ignition mode.
4. The system (1) according to any one of claims 1 to 3, characterized in that, The third DC-DC converter (3c) is configured to provide electric power in the non-ignition state with only passive cooling.
5. The system (1) according to any one of claims 1-4, characterized in that, The third DC-DC converter (3c) is configured to be directly electrically connected to the batteries (2a, 2b) without any switch therebetween.
6. The system (1) according to any one of claims 1-5, further comprising at least one power distribution unit (5a, 5b), the at least one power distribution unit (5a, 5b) being configured to supply the low DC voltage to a plurality of loads, wherein, The power distribution unit (5a, 5b) is electrically connected to the second DC-DC converter and selectively electrically connected to the first DC-DC converter (3a) or the third DC-DC converter (3c).
7. The system (1) according to claim 6, characterized in that, The system (1) is configured such that in an ignition state of the vehicle, the first DC-DC converter (3a) is electrically connected to the power distribution unit (5a, 5b), and in a non-ignition state, the third DC-DC converter (3c) is electrically connected to the power distribution unit (5a, 5b).
8. The system (1) according to any one of claims 6-7, characterized in that, The power distribution unit (5a, 5b) is configured to electrically connect each of the plurality of loads to the first DC-DC converter (3a) or to the second DC-DC converter (3b) or the third DC-DC converter (3c).
9. The system (1) according to any one of claims 6-8, characterized in that, The power distribution units (5a, 5b) are configured to actively distribute the plurality of loads between the first DC-DC converter (3a) and the second DC-DC converter (3b) in an ignition state of the vehicle such that the first battery (2a) and the second battery (2b) are substantially balanced.
10. The system (1) according to any one of claims 6-9, characterized in that, The power distribution units (5a, 5b) include at least one switch for separating a quality management load from a safety-critical load.
11. The system (1) according to any one of claims 6-10, further comprising: A first electrical main fuse box eMFB (7a) electrically connected to both the first DC-DC converter (3a) and the third DC-DC converter (3c) to selectively supply power to a load through the first DC-DC converter (3a) or the third DC-DC converter (3b), and electrically connected to a first power distribution unit (5a) and a second power distribution unit (5b); And A second eMFB (7b) electrically connected to the second DC-DC converter (3b), the first power distribution unit (5a), and the second power distribution unit (5b).
12. The system (1) according to claim 11, further comprising a switch (8) configured to selectively electrically connect the first DC-DC converter (3a) or the third DC-DC converter (3c) to the first eMFB (7a).
13. The system (1) according to any one of claims 1-12, characterized in that, The low DC voltage is a nominal voltage of 60V or less, preferably a nominal voltage of 12V, 24V, or 48V.
14. The system (1) according to any one of claims 1-13, characterized in that, The high voltage is a nominal voltage greater than 60V, preferably a nominal voltage of 200V, 400V, 800V, or higher.
15. The system (1) according to any one of claims 1-14, characterized in that, The high-voltage batteries (5a, 5b) are adapted to power an electric motor of the vehicle.