Vehicle electrical system arrangement for a vehicle, and vehicle having such a vehicle electrical system arrangement
A cascaded dual DC/DC converter system optimizes power distribution by dividing low-voltage consumers into groups based on environmental conditions, addressing inefficiencies in existing systems and reducing converter size, weight, and cost.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- MERCEDES BENZ GROUP AG
- Filing Date
- 2025-09-08
- Publication Date
- 2026-06-25
AI Technical Summary
Existing on-board electrical systems in vehicles require large and costly DC/DC converters to handle varying power demands for different low-voltage consumers under different environmental conditions, leading to inefficiencies in installation space, weight, and cost.
A cascaded dual DC/DC converter system is used, dividing low-voltage consumers into two groups based on environmental conditions, with one converter converting high-voltage to 48V and the other converting 48V to 12V, optimizing power distribution and reducing converter size and weight.
This approach reduces the overall size, weight, and cost of the DC/DC converter system while ensuring all low-voltage consumers can operate efficiently under varying conditions, achieving synergies in power utilization and minimizing conductor stress.
Smart Images
Figure EP2025075506_25062026_PF_FP_ABST
Abstract
Description
[0001] Mercedes-Benz Group AG
[0002] On-board electrical system arrangement for a vehicle and vehicle with such an on-board electrical system arrangement
[0003] The invention relates to an on-board electrical system arrangement for a vehicle according to the features of the preamble of claim 1 and a vehicle.
[0004] As described in US 2015 / 0258947 A1, a DC / DC converter with variable setpoint control is known from the prior art. The DC / DC converter is installed in a vehicle to convert a high-voltage voltage from a power source to a low-voltage voltage. It comprises a primary converter, a secondary converter, and a DC / DC module that controls the operation of the secondary converter based on a setpoint threshold and the power output of the primary converter. The setpoint threshold is variably adjustable.
[0005] The invention is based on the objective of providing an improved on-board electrical system arrangement for a vehicle compared to the prior art and a vehicle improved compared to the prior art.
[0006] The problem is solved according to the invention by a vehicle electrical system arrangement for a vehicle with the features of claim 1 and a vehicle with the features of claim 9.
[0007] Advantageous embodiments of the invention are the subject of the dependent claims.
[0008] A vehicle electrical system comprises a high-voltage battery, a DC / DC converter (also referred to as a DC-DC converter), and several low-voltage electrical loads. The DC / DC converter is connected to the high-voltage battery, and the low-voltage electrical loads are connected to the DC / DC converter. According to the invention, the DC / DC converter comprises a first DC / DC converter unit and a second DC / DC converter unit. The first DC / DC converter unit is configured to convert a high-voltage voltage from the high-voltage battery, for example, 800 V or 400 V, into a first low-voltage voltage, in particular 48 V. The second DC / DC converter unit is configured to convert the first low-voltage voltage into a second low-voltage voltage that is lower than the first low-voltage voltage, in particular 12 V.
[0009] One input of the first DC / DC converter unit is connected to the high-voltage battery, and one input of the second DC / DC converter unit is connected to an output of the first DC / DC converter unit. The DC / DC converter is thus configured, in particular, as a cascaded DC / DC converter, specifically as a cascaded dual DC / DC converter.
[0010] The low-voltage electrical loads are each assigned to a first group or a second group, with the first group comprising all low-voltage electrical loads with a nominal voltage corresponding to the first low-voltage voltage and the second group comprising all low-voltage electrical loads with a nominal voltage corresponding to the second low-voltage voltage. The low-voltage loads of the first group are connected to the output of the first DC / DC converter unit, and the low-voltage loads of the second group are connected to an output of the second DC / DC converter unit.
[0011] Low-voltage electrical consumers whose normal operation is only intended under specified primary environmental conditions are only present in the first group, and low-voltage electrical consumers whose normal operation is only intended under specified secondary environmental conditions that differ from the primary environmental conditions are only present in the second group. Environmental conditions are, in particular, conditions, especially ambient temperature conditions, that exist in the external environment of the vehicle electrical system, especially in the external environment of the vehicle containing the vehicle electrical system.
[0012] The specified environmental conditions are, for example, seasons, especially summer and winter, and / or ambient temperature ranges, where ambient temperatures of the first ambient temperature range are greater or less than ambient temperatures of the second ambient temperature range.
[0013] Normal operation is, in particular, a typical and / or usual and / or predominant use case for the respective low-voltage consumer by vehicle users and vehicles. Normal operation differs, for example, from test operation and / or exceptional operation and / or operation of the respective low-voltage consumer that is unusual and / or rarely occurring for vehicles and vehicle users, and / or from operation of the respective low-voltage consumer at low, especially very low, power, particularly with a power output significantly reduced compared to normal operation, especially by a factor of several.
[0014] Low-voltage consumers whose normal operation is only intended under specified first environmental conditions are, for example, cooling low-voltage consumers, and low-voltage consumers whose normal operation is only intended under specified second environmental conditions are, for example, heating low-voltage consumers, or vice versa.
[0015] The low-voltage consumers whose normal operation is only intended under specified first environmental conditions include, for example, at least one suction fan and / or an electrically operated air conditioning device and / or at least one coolant pump and / or at least one blower, and the low-voltage consumers whose normal operation is only intended under specified second environmental conditions include, for example, at least one seat heater or several seat heaters, and / or at least one windshield heater or several windshield heaters, and / or at least one steering wheel heater and / or at least one exterior mirror heater or several exterior mirror heaters, and / or at least one windshield washer device heater and / or at least one electrically operated passenger compartment heater and / or at least one electrically operated auxiliary heater, or vice versa.
[0016] The first group includes, for example, additional low-voltage electrical appliances besides those whose normal operation is only intended under specified primary environmental conditions. The second group includes, for example, additional low-voltage electrical appliances besides those whose normal operation is only intended under specified secondary environmental conditions.
[0017] For example, one of the two groups includes, as additional low-voltage electrical consumers, a low-voltage battery and / or an electric steering device and / or an electric braking device. The low-voltage battery acts as a low-voltage consumer, at least while it is being charged. The low-voltage battery can also supply electrical energy to the other low-voltage consumers in its group.
[0018] It is specifically designed that the total power output of the DC / DC converter is less than the sum of the maximum power outputs of all low-voltage loads. The DC / DC converter is specifically designed and configured accordingly.
[0019] In one embodiment, the following is provided:
[0020] The first DC / DC converter unit is designed to convert the high-voltage voltage of the high-voltage battery (e.g., 800V or 400V) into the first low-voltage voltage of 48V. The second DC / DC converter unit is designed to convert the first low-voltage voltage of 48V into the second low-voltage voltage of 12V. The input of the first DC / DC converter unit is connected to the high-voltage battery, and the input of the second DC / DC converter unit is connected to the output of the first DC / DC converter unit. The first group consists of all low-voltage loads with a nominal voltage corresponding to the first low-voltage voltage of 48V, and the second group consists of all low-voltage loads with a nominal voltage corresponding to the second low-voltage voltage of 12V.The low-voltage loads of the first group are connected to the output of the first DC / DC converter unit, and the low-voltage loads of the second group are connected to the output of the second DC / DC converter unit. Low-voltage loads whose normal operation is only intended under predefined first ambient conditions are cooling low-voltage loads, for example, at least one suction fan and / or an electrically operated air conditioning device and / or at least one coolant pump and / or at least one blower. These low-voltage loads are only present in the first group. The relevant predefined ambient conditions include the season of summer and / or associated ambient conditions and / or the first ambient temperature range with ambient temperatures that are higher than the ambient temperatures of the second ambient temperature range, in particular summer ambient temperatures.Low-voltage consumers whose normal operation is only intended under specified second environmental conditions that differ from the first are heating low-voltage consumers, for example, at least one seat heater and / or at least one windshield heater and / or at least one steering wheel heater and / or at least one exterior mirror heater and / or at least one windshield washer heater and / or at least one electrically operated passenger compartment heater and / or at least one electrically operated auxiliary heater. These low-voltage consumers are only present in the second group. The relevant specified environmental conditions include the winter season and / or associated environmental conditions and / or the second ambient temperature range with ambient temperatures that are lower than the ambient temperatures of the first ambient temperature range, in particular winter ambient temperatures.
[0021] At least the second group, for example, has additional low-voltage consumers besides the low-voltage consumers whose normal operation is only intended under specified second environmental conditions, such as the low-voltage battery and / or the electric steering device and / or the electric braking device.
[0022] In this embodiment, the low-voltage loads, whose normal operation is intended only during summer and / or associated ambient conditions, particularly summer temperatures, thus exhibit the nominal voltage corresponding to the first low-voltage voltage of 48V. This has the advantage of reducing the overall current required for the conversion from the high-voltage voltage to the second low-voltage voltage of 12V, thereby reducing conductor cross-sections and relieving stress on contacts. Otherwise, high temperature stress would occur during summer with high currents. This embodiment thus enables further savings in costs, weight, and installation space, in addition to the savings achieved by the solution according to the invention.
[0023] The electrical system arrangement includes, in particular, a high-voltage electrical system, especially with the high-voltage battery, and a low-voltage electrical system with two low-voltage sub-systems. The first low-voltage sub-system comprises the first group of low-voltage consumers, and the second low-voltage sub-system comprises the second group of low-voltage consumers.
[0024] A vehicle according to the invention has such an on-board electrical system arrangement. The vehicle is, in particular, an electric vehicle, hybrid vehicle, or fuel cell vehicle. It has, in particular, at least one electric drive motor for propelling the vehicle, for whose electrical energy supply the high-voltage battery is provided.
[0025] The described solution takes advantage of the fact that certain low-voltage consumers are only needed in summer or at corresponding ambient temperatures, and therefore only draw their full power then, while other low-voltage consumers are only needed in winter or at corresponding ambient temperatures, and therefore only draw their full power then. In the prior art, low-voltage sub-systems with 48V and 12V are known, where each of these sub-systems is connected to the high-voltage battery via its own DC / DC converter. That is, one DC / DC converter converts the high-voltage voltage to 48V, and the other DC / DC converter converts the high-voltage voltage to 12V. This necessitates dimensioning both DC / DC converters to meet the power requirements for winter or summer operation, depending on which requires the most power.This results in disadvantages in terms of installation space, weight and cost due to the high power output of the DC / DC converters, even though this high power is only necessary in some cases for winter or summer conditions.
[0026] By using the described cascaded DC / DC converter, in particular the cascaded dual DC / DC converter, with the two low-voltage voltage levels in cascaded form, which makes it possible in particular to convert the full power from the high-voltage voltage level to the first low-voltage voltage level of, for example, 48V and then further to the second low-voltage voltage level of, for example, 12V, and by the described division of the low-voltage consumers into the two groups and thus onto the two low-voltage sub-networks with these two low-voltage voltage levels, the above-described, and in particular smaller, dimensioning of the DC-DC converter compared to the prior art is made possible, in particular the dimensioning for a total power which, in particular due to the design and the described operating strategy,The total power consumption does not have to be equal to the sum of the full power consumption of the low-voltage consumers in the first group in winter / summer conditions, but can in particular be lower.
[0027] With the described solution, in particular by using the described cascaded DC / DC converter, especially the cascaded dual DC / DC converter, if there is a large power demand on the first low-voltage voltage level of, for example, 48V, the full power of the DC / DC converter can be used on this first low-voltage voltage level of, for example, 48V, and if there is a large power demand on the second low-voltage voltage level of, for example, 12V, the full power of the DC / DC converter can be used on this second low-voltage voltage level of, for example, 12V.
[0028] The described solution, in particular the use of the described cascaded DC / DC converter, especially the cascaded dual DC / DC converter, in the described manner, achieves, in particular, the utilization of synergies within the DC / DC converter for the first low-voltage component, for example 48V, and the second low-voltage component, for example 12V. These synergies are not available with two separate DC / DC converters.
[0029] Furthermore, the described solution allows for a smaller dimensioning of the described cascaded DC / DC converter, in particular the cascaded dual DC / DC converter, especially without restrictions on the supply of low-voltage consumers.
[0030] The described solution ensures, in particular, that a vehicle user can activate all required comfort functions and associated low-voltage consumers in the vehicle electrical system.
[0031] The described solution eliminates the need for a large or additional DC / DC converter.
[0032] The described solution enables savings in costs, weight, and installation space. Exemplary embodiments of the invention are explained in more detail below with reference to the drawings.
[0033] This shows:
[0034] Fig. 1 schematically shows a vehicle with an on-board electrical system arrangement, and
[0035] Fig. 2 schematically shows the power requirements of low-voltage sub-systems of the on-board network arrangement in a winter case and in a summer case.
[0036] Corresponding parts are marked with the same reference symbols in all figures.
[0037] With reference to Figures 1 and 2, a vehicle electrical system arrangement 1 for a vehicle 2 and a vehicle 2 with such a vehicle electrical system arrangement 1, as shown in Figure 1, are described below. The vehicle 2 is in particular an electric vehicle, hybrid vehicle or fuel cell vehicle.
[0038] The on-board electrical system 1 comprises a high-voltage battery 3, a DC / DC converter 4 and several low-voltage electrical consumers NV1, NV2, WNV1, WNV2, wherein the DC / DC converter 4 is connected to the high-voltage battery 3 and the low-voltage electrical consumers NV1, NV2, WNV1, WNV2 are connected to the DC / DC converter 4.
[0039] The DC / DC converter 4 comprises a first DC / DC converter unit 4.1 and a second DC / DC converter unit 4.2. The first DC / DC converter unit 4.1 is configured to convert a high-voltage voltage from the high-voltage battery 3, for example 800 V or 400 V, into a first low-voltage voltage, in particular 48 V. The second DC / DC converter unit 4.2 is configured to convert the first low-voltage voltage into a second low-voltage voltage that is lower than the first low-voltage voltage, in particular 12 V.
[0040] An input E1 of the first DC / DC converter unit 4.1 is connected to the high-voltage battery 3, switchable in the illustrated example via a switching unit 5, for example a contactor. The input E1 of the first DC / DC converter unit 4.1 can thus be disconnected from the high-voltage battery 3 by opening the switching unit 5 and connected to the high-voltage battery 3 by closing the switching unit 5. An input E2 of the second DC / DC converter unit 4.2 is connected to an output A1 of the first DC / DC converter unit 4.1. The DC / DC converter 4 is therefore designed, in particular, as a cascaded DC / DC converter 4, specifically as a cascaded dual DC / DC converter 4.
[0041] The low-voltage electrical loads NV1, NV2, WNV1, WNV2 are each assigned to a first group G1 or a second group G2, where the first group G1 comprises all low-voltage electrical loads NV1, WNV1 with a nominal voltage corresponding to the first low-voltage voltage, and the second group G2 comprises all low-voltage electrical loads NV2, WNV2 with a nominal voltage corresponding to the second low-voltage voltage. The low-voltage loads NV1, WNV1 of the first group G1 are connected to output A1 of the first DC / DC converter unit 4.1, and the low-voltage loads NV2, WNV2 of the second group G2 are connected to output A2 of the second DC / DC converter unit 4.2.
[0042] Low-voltage electrical consumers NV1, whose normal operation is only intended under specified first ambient conditions, are only present in the first group G1, and low-voltage electrical consumers NV2, whose normal operation is only intended under specified second ambient conditions that differ from the first ambient conditions, are only present in the second group G2. Ambient conditions are, in particular, conditions, especially ambient temperature conditions, that exist in an external environment of the on-board electrical system 1, in particular in an external environment of the vehicle 2 comprising the on-board electrical system 1.
[0043] The specified environmental conditions are, for example, seasons, especially summer and winter, and / or ambient temperature ranges, where ambient temperatures of the first ambient temperature range are greater or less than ambient temperatures of the second ambient temperature range.
[0044] The low-voltage consumers NV1, whose normal operation is only intended under specified first environmental conditions, are, for example, cooling low-voltage consumers NV1, and the low-voltage consumers NV2, whose normal operation is only intended under specified second environmental conditions, are, for example, heating low-voltage consumers NV2, or vice versa.
[0045] The low-voltage consumers NV1, whose normal operation is only intended under specified first environmental conditions, include, for example, at least one suction fan and / or an electrically operated air conditioning device and / or at least one coolant pump and / or at least one blower, and the low-voltage consumers NV2, whose normal operation is only intended under specified second environmental conditions, include, for example, at least one seat heater 6 or several seat heaters 6, and / or at least one windshield heater or several windshield heaters, and / or at least one steering wheel heater and / or at least one exterior mirror heater or several exterior mirror heaters, and / or at least one windshield washer device heater and / or at least one electrically operated passenger compartment heater and / or at least one electrically operated auxiliary heater, or vice versa.
[0046] The first group G1, for example, includes, in addition to the low-voltage electrical consumers NV1, whose normal operation is only intended under specified initial environmental conditions, further electrical
[0047] The second group G2 includes, for example, low-voltage consumers WNV1. In addition to the low-voltage electrical consumers NV2, whose normal operation is only intended under specified second environmental conditions, the second group G2 also includes further low-voltage electrical consumers WNV2.
[0048] For example, one of the two groups G1, G2 (in the illustrated example, the second group G2) comprises, as further low-voltage electrical consumers WNV2, a low-voltage battery 7 and / or an electric steering device 8 and / or an electric braking device 9. The low-voltage battery 7 acts as a further low-voltage electrical consumer WNV2, at least while it is being charged. The low-voltage battery 7 can also supply electrical energy to the other low-voltage consumers NV2, WNV2 in its group G2.
[0049] It is specifically intended that the total power output of the DC / DC converter 4 is less than the sum of the maximum power outputs of all low-voltage loads NV1, NV2, WNV1, WNV2. The DC / DC converter 4 is specifically designed and configured accordingly.
[0050] In the embodiment shown as an example in Figure 1, the following is provided:
[0051] The first DC / DC converter unit 4.1 is designed to convert the high-voltage voltage of the high-voltage battery 3 of, for example, 800V or 400V into the first low-voltage voltage of 48V, and the second DC / DC converter unit 4.2 is designed to convert the first low-voltage voltage of 48V into the second low-voltage voltage of 12V.
[0052] The input E1 of the first DC / DC converter unit 4.1 is connected to the high-voltage battery 3 in the manner described above, and the input E2 of the second DC / DC converter unit 4.2 is connected to the output A1 of the first DC / DC converter unit 4.1.
[0053] The first group G1 includes all low-voltage consumers NV1, WNV1 with a nominal voltage of 48V corresponding to the first low-voltage voltage, and the second group G2 includes all low-voltage consumers NV2, WNV2 with a nominal voltage of 12V corresponding to the second low-voltage voltage.
[0054] The low-voltage loads NV1, WNV1 of the first group G1 are connected to output A1 of the first DC / DC converter unit 4.1 and the
[0055] Low-voltage consumers NV2, WNV2 of the second group G2 are connected to output A2 of the second DC / DC converter unit 4.2.
[0056] Low-voltage loads NV1, whose normal operation is only intended under specified first ambient conditions, are cooling low-voltage loads NV1, for example, at least one suction fan and / or an electrically operated air conditioning device and / or at least one coolant pump and / or at least one blower. These low-voltage loads NV1 are only present in the first group G1. The relevant specified ambient conditions include the summer season and / or associated ambient conditions and / or the first ambient temperature range with ambient temperatures higher than those of the second ambient temperature range, in particular summer ambient temperatures.
[0057] Low-voltage consumers NV2, whose normal operation is only intended under specified second environmental conditions that differ from the first, are heating low-voltage consumers NV2, for example, at least one seat heater 6 and / or at least one windshield heater and / or at least one steering wheel heater and / or at least one exterior mirror heater and / or at least one windshield washer heater and / or at least one electrically operated passenger compartment heater and / or at least one electrically operated auxiliary heater. These low-voltage consumers NV2 are only present in the second group G2. The relevant specified environmental conditions include the winter season and / or associated environmental conditions and / or the second ambient temperature range with ambient temperatures that are lower than the ambient temperatures of the first ambient temperature range, in particular winter ambient temperatures.At least the second group G2, for example, has additional low-voltage consumers WNV2, in addition to the low-voltage consumers NV2, whose normal operation is only intended under specified second environmental conditions, such as the low-voltage battery 7 and / or the electric steering device 8 and / or the electric braking device 9.
[0058] In this embodiment, the low-voltage consumers NV1, whose normal operation is intended only during summer and / or associated ambient conditions, particularly summer temperatures, thus exhibit the nominal voltage corresponding to the first low-voltage voltage of 48V. This has the advantage of reducing the overall current required for the conversion from the high-voltage voltage to the second low-voltage voltage of 12V, thereby reducing conductor cross-sections and relieving stress on contacts. Otherwise, high temperature stress would occur during summer with high currents. This embodiment thus enables further savings in costs, weight, and installation space, in addition to the savings achieved by the solution according to the invention.
[0059] The on-board electrical system arrangement 1 comprises, in particular, a high-voltage on-board electrical system HV-BN, especially with the high-voltage battery 3, and a low-voltage on-board electrical system NV-BN with two low-voltage sub-on-board electrical systems NV-BN1 and NV-BN2. The first low-voltage sub-on-board electrical system NV-BN1 comprises the first group G1 of the low-voltage consumers NV1 and WNV1, and the second low-voltage sub-on-board electrical system NV-BN2 comprises the second group G2 of the low-voltage consumers NV2 and WNV2.
[0060] To fully utilize the potential of the cascaded dual DC / DC converter 4, an overlap of the summer and winter power demands of the low-voltage loads NV1, NV2, WNV1, WNV2 of the two groups G1, G2 is necessary. This is achieved by the described division, in particular of the low-voltage loads NV1, NV2, whose normal operation is only intended under the specified first and second ambient conditions, into the two groups G1, G2, as schematically illustrated in Figure 2.
[0061] Figure 2 shows the power requirement LB1 of the first group G1, consisting of low-voltage consumers NV1, connected to output A1 of the first DC / DC converter unit 4.1 and thus operating at 48V. Normal operation of this group is only intended under the specified first, particularly summer, ambient conditions. Figure 2 also shows the power requirement LB2 of the second group G2, consisting of low-voltage consumers NV2, connected to output A2 of the second DC / DC converter unit 4.2 and thus operating at 12V. Normal operation of this second group is only intended under the specified second, particularly winter, ambient conditions. The power requirement is represented as WF (winter operation of vehicle 2) and SF (summer operation of vehicle 2). The sum of the power requirements LB1 and LB2 of the two groups G1 and G2 yields a total power requirement GLB for the low-voltage consumers NV1, NV2, WNV1, and WNV2.As can be seen from Figure 2, this total power requirement GLB is achieved through the described solution, in particular through the described division of the.
[0062] Low-voltage consumers NV1, NV2, whose normal operation is only intended under the specified first or second environmental conditions, are advantageously divided into the two groups G1, G2, WF in winter and SF in summer, preferably of the same size.
[0063] For example, in winter there is a total power requirement GLB of 4*A kW, of which 1*A kW is connected to 48V of output A1 of the first DC / DC converter unit 4.1 and 3*A kW are connected to 12V of output A2 of the second DC / DC converter unit 4.2, and in summer there is the same total power requirement GLB of 3*B kW, where 2*B kW are connected to 48V of output A1 of the first DC / DC converter unit 4.1 and 1*B kW is connected to 12V of output A2 of the second DC / DC converter unit 4.2.
[0064] In order to avoid having to design the 48V component at 2*B and the 12V component at 3*A in an alternative parallel DC / DC concept, and thus increasing the total power GLB of such an alternative solution with two parallel DC / DC converters in this example by over 40% (approx. 1.4 * GLB kW = 2*B kW + 3*A kW), even though less is needed in actual applications, the cascaded DC / DC converter 4, which is dimensioned for the total power GLB, is used in the described solution.
[0065] Generally, due to temperature fluctuations, it makes sense to locate the "summer consumers," i.e., the low-voltage consumers NV1, whose normal operation is only intended under summer ambient conditions, in the 48V sub-system, i.e., in the first low-voltage sub-system NV-BN1. However, a reverse operating strategy is also possible.
[0066] The following describes two example scenarios: one for winter (WF) and one for summer (SF).
[0067] In winter mode (WF), during a winter warm-up drive, all low-voltage consumers NV2, such as seat heaters 6, rear window heater, etc., are required and draw power from the low-voltage electrical system NV-BN. Summer consumers, especially the cooling low-voltage consumers NV1, such as intake fans, coolant pumps, air conditioning blowers, etc., are not required in winter or only to a limited extent. The DC / DC converter 4 must be able to supply all low-voltage consumers NV2 with heat. If the low-voltage consumers NV2 are connected to output A2 of the second DC / DC converter unit 4.2 with 12V, as in the example shown in Figure 1, the dual DC / DC converter 4 supplies the 12V level with a high power output, while only a small portion needs to be supplied to the 48V level.
[0068] In summer conditions (SF), during a summer mountain ascent, many thermal management / cooling components are required, for example, suction fans, coolant pumps, air conditioning blowers – i.e., the cooling low-voltage consumers NV1 – and draw high current from the low-voltage on-board network NV-BN. The winter consumers, especially the heating low-voltage consumers NV2, for example,
[0069] Seat heaters 6, rear window heater, etc., are not needed in summer. The DC / DC converter 4 must be able to supply all thermal management components, i.e., all cooling low-voltage consumers NV1. If the thermal management components, i.e., the cooling low-voltage consumers NV1, are connected to output A1 of the first DC / DC converter unit 4.1 with 48V, as in the example shown in Figure 1, the dual DC / DC converter 4 supplies the 48V level with a high power output, while a smaller portion needs to be supplied to the 12V level.
Claims
Mercedes-Benz Group AG Patent claims 1. On-board electrical system arrangement (1) for a vehicle (2), comprising a high-voltage battery (3), a DC / DC converter (4) and several Low-voltage consumers (NV1, NV2, WNV1, WNV2), wherein the DC / DC converter (4) is connected to the high-voltage battery (3) and the Low-voltage loads (NV1, NV2, WNV1, WNV2) are connected to the DC / DC converter (4), characterized in that the DC / DC converter (4) comprises a first DC / DC converter unit (4.1) configured to convert a high-voltage voltage from the high-voltage battery (3) into a first low-voltage voltage, and a second DC / DC converter unit (4.2) configured to convert the first low-voltage voltage into a second low-voltage voltage that is lower than the first low-voltage voltage, wherein an input (E1) of the first DC / DC converter unit (4.1) is connected to the high-voltage battery (3), and an input (E2) of the second DC / DC converter unit (4.2) is connected to an output (A1) of the first DC / DC converter unit (4.1). Low-voltage consumers (NV1, NV2, WNV1, WNV2) are each assigned to a first group (G1) or a second group (G2), wherein the first group (G1) comprises all low-voltage consumers (NV1, WNV1) with a nominal voltage corresponding to the first low-voltage voltage and the second group (G2) comprises all low-voltage consumers (NV2, WNV2) with a nominal voltage corresponding to the second low-voltage voltage, wherein the Low-voltage loads (NV1, WNV1) of the first group (G1) are connected to the output (A1) of the first DC / DC converter unit (4.1) and the low-voltage loads (NV2, WNV2) of the second group (G2) are connected to a Output (A2) of the second DC / DC converter unit (4.2) are connected, and low-voltage loads (NV1), whose normal operation is only possible under specified conditions, are connected. Low-voltage consumers (NV2), whose normal operation is only intended under specified second environmental conditions that differ from the first environmental conditions, are only present in the second group (G2).
2. On-board electrical system arrangement (1) according to claim 1 , characterized in that the first low voltage is 48V and the second low voltage is 12V.
3. On-board network arrangement (1) according to one of the preceding claims, characterized in that the specified ambient conditions are seasons and / or ambient temperature ranges, wherein ambient temperatures of the first ambient temperature range are greater or less than ambient temperatures of the second ambient temperature range.
4. On-board electrical system arrangement (1) according to one of the preceding claims, characterized in that the low-voltage consumers (NV1), whose normal operation is only provided under specified first ambient conditions, are cooling low-voltage consumers (NV1), and the Low-voltage consumers (NV2), whose normal operation is only intended under specified second environmental conditions, are heating low-voltage consumers (NV2), or vice versa.
5. On-board electrical system arrangement (1) according to one of the preceding claims, characterized in that the low-voltage consumers (NV1), whose normal operation is provided only under specified first ambient conditions, comprise at least one suction fan and / or an electrically operated air conditioning device and / or at least one coolant pump and / or at least one blower, and the low-voltage consumers (NV2), whose normal operation is provided only under specified second ambient conditions, comprise at least one seat heater (6) and / or at least one windscreen heater and / or at least one steering wheel heater and / or at least one exterior mirror heater and / or at least one The vehicle must include a windscreen cleaning device heater and / or at least one electrically operated passenger compartment heater and / or at least one electrically operated auxiliary heater, or vice versa.
6. On-board electrical system arrangement (1) according to one of the preceding claims, characterized in that - the first group (G1) in addition to the low-voltage consumers (NV1), whose normal operation is only intended under specified initial environmental conditions, has further low-voltage consumers (WNV1), and / or - the second group (G2) in addition to the low-voltage consumers (NV2), whose normal operation is only intended under specified second environmental conditions, has further low-voltage consumers (WNV2).
7. On-board electrical system arrangement (1) according to claim 6, characterized in that one of the two groups (G1, G2) comprises a low-voltage battery (7) and / or an electric steering device (8) and / or an electric braking device (9).
8. On-board power supply arrangement (1) according to one of the preceding claims, characterized in that a total power of the DC / DC converter (4) is less than a sum of the maximum powers of all low-voltage consumers (NV1, NV2, WNV1, WNV2).
9. Vehicle (2) comprising a vehicle electrical system arrangement (1) according to one of the preceding claims.
10. Vehicle (2) according to claim 9, characterized by a design as an electric vehicle, hybrid vehicle or fuel cell vehicle.