Automotive high-voltage electrical system

Abstract

High-voltage on-board power supply system (100) of a vehicle having a high-voltage battery (102) and a first charging device (106) which converts a single-phase or multi-phase alternating voltage applied to its input via a connection (108) into a direct voltage regulated within a narrow voltage range and applies it to a high-voltage intermediate circuit (110), wherein two bidirectionally operable direct-voltage converters (112a, 112b) are connected in parallel to one another to the high-voltage intermediate circuit (110), which, in a second operating mode, are configured to individually or jointly charge the high-voltage battery (102) from the high-voltage intermediate circuit (110), and, in a first operating mode, to individually or jointly supply the high-voltage intermediate circuit (110) from the high-voltage battery (102) with a direct voltage, wherein a high-voltage consumer (116) is connected to the high-voltage intermediate circuit (110).

Description

[0001] The present invention relates to high-voltage electrical systems of motor vehicles, in particular fully electric and hybrid vehicles, with an electrical energy storage device comprising at least one battery and a high-voltage intermediate circuit. The present invention also relates to methods for operating a high-voltage electrical system according to the invention in different operating modes. BACKGROUND

[0002] Electric vehicles, i.e. hybrid vehicles (Hybrid Electric Vehicle, HEV), plug-in hybrid vehicles (PHEV), and purely electric vehicles (EV), comprise a high-voltage electrical system comprising a high-voltage battery, an engine control unit connected to the high-voltage battery, and an electric drive motor connected to the engine control unit, as well as other high-voltage components that depend on the type and equipment of the electric vehicle, e.g., air conditioning compressors, heaters, and the like. If no DC motor is used, a frequency converter can convert the direct current provided by the high-voltage battery into usually three alternating current phases, which drive an electric motor designed for operation with alternating current.

[0003] A variety of high-voltage vehicle electrical systems and charging concepts are known from the prior art. For example, DE 10 2012 203 612 A1 discloses a battery charger with a rectifier to which a power factor correction circuit is connected. The power factor correction circuit provides a DC voltage in an intermediate circuit, from which a high-voltage battery can be charged by one or both of two DC-DC converters connected in parallel. The DC-DC converters can be bidirectional, so that a first of the two DC-DC converters can feed the intermediate circuit from the high-voltage battery, and the second of the two DC-DC converters can charge a low-voltage battery from it.

[0004] DE 10 2018 221 519 B4 and DE 10 2020 204 336 A1 disclose a vehicle-mounted charging device in which a rectifier rectifies an alternating voltage and provides it in an intermediate circuit. The voltage provided by the rectifier depends on whether a single-phase or multi-phase alternating voltage source is connected. Two DC-DC converters can be connected either in parallel to the intermediate circuit or in series with each other, so that half the voltage of the intermediate circuit is applied to their inputs. The DC-DC converters can be bidirectional, so that the intermediate circuit can be fed by the DC-DC converters. A third DC-DC converter is designed for an input voltage that corresponds to twice the input voltage of the other two DC-DC converters.By activating the DC-DC converters accordingly, an adjustment can be made to the intermediate circuit voltage provided by the rectifier and / or to the power requirement.

[0005] DE 10 2014 109 430 A1 discloses an energy storage system for a vehicle equipped with at least two electric motors, which also includes two energy storage cells. The energy storage cells can be charged in series by a charger or separately and independently by their own chargers.

[0006] DE 10 2019 200 909 A1 discloses a method for charging a vehicle accumulator, the battery banks of which can be connected in series or parallel to one another depending on the number of alternating voltage phases applied to a rectifier.

[0007] DE 10 2016 008 265 A1 discloses a method for operating a motor vehicle with an electrical energy storage device. Energy storage modules can be connected in parallel when charging the energy storage device, and in series when operating from the energy storage device, so that a higher voltage is available in the high-voltage electrical system. Additionally, an AC charger can be connected simultaneously, which supplies components of the high-voltage electrical system with a voltage higher than the charging voltage. Charging the energy storage device from the AC charger is not provided.

[0008] DE 10 2017 010 998 A1 discloses an energy storage device with two energy storage devices for a motor vehicle, in which the energy storage devices can be connected either in parallel or in series to one another in order to either supply a first or second operating voltage to electrical consumers or to be charged with a first or second operating voltage.

[0009] DE 10 2019 129 785 A1 discloses an integrated energy supply system for an electrically powered vehicle, in which two high-voltage direct current sources each supply a first and second high-voltage electrical system, respectively, and from this supply one or two drive motors with electrical energy. Energy exchange between the two high-voltage electrical systems is possible via a bidirectional, galvanically isolated high-voltage DC-DC converter. A DC-DC converter is connected to each of the high-voltage electrical systems, allowing a low-voltage electrical system to be supplied from both high-voltage electrical systems. Using a switch, each of the high-voltage direct current sources can be charged individually and optionally from a DC voltage source or, via a rectifier, from an AC voltage source.When charging from an AC voltage source, the unregulated rectified voltage is fed to the respective energy storage device via the high-voltage DC converter.

[0010] The high-voltage system of most electric cars available today is based on an architecture with a system voltage of approximately 400 volts, whereby the battery voltage can fluctuate considerably depending on the state of charge. Assuming a lithium-based battery with a nominal voltage of 3.6 V per cell, approximately 110 cells are connected in series to achieve the nominal system voltage. The end-of-discharge voltage of a typical lithium battery cell is approximately 2.5 V, and the end-of-charge voltage is approximately 4.2 V. This results in a state-of-charge-dependent voltage range of approximately 275 V to 460 V for a battery with 110 cells connected in series. The loads supplied by the battery assumed in this example must therefore be designed for an input voltage range of at least approximately 185 V. In practice, an input voltage range of 200 V is assumed to account for voltage drops on cables.Electrical loads can generally only be operated with good efficiency within a narrow nominal supply voltage range. While electrical loads can be designed for operation over a wide input voltage range, efficiency may be lower outside the nominal supply voltage range. However, efficient use of the energy stored in the vehicle's battery is particularly important for battery-powered vehicles.

[0011] It is therefore an object of the present invention to provide a high-voltage vehicle electrical system which enables efficient operation of components connected thereto.

[0012] The systems required for highly automated driving, particularly the safety-relevant steering and braking systems, operate at a voltage of 12 V. This is due, among other things, to regulatory approval requirements, as such system components are already approved in large numbers for vehicles with combustion engines, which generally have a 12 V electrical system, and developing and approving new systems for higher supply voltages is expensive and complex. Since other proven vehicle systems also operate at 12 V, such as entertainment systems and the like, electric vehicles always have a 12 V electrical system, which may have its own 12 V battery. However, the additional 12 V battery adds weight and requires additional installation space. In every vehicle, not just electric vehicles, additional weight also requires additional energy, especially during acceleration.While this energy can be partially recovered in electric vehicles during deceleration, a lower weight in vehicle construction always results in improved driving dynamics and lower energy consumption during operation, which is particularly desirable for electric vehicles. Since the 12 V electrical system must always be supplied with sufficient energy to power the safety-relevant systems, only a small-capacity 12 V battery is installed for reasons of weight savings, if at all. A DC / DC converter connected to the high-voltage battery is used, which feeds the 12 V electrical system from the high-voltage battery and, if necessary, also charges the 12 V battery.

[0013] It is therefore a further object of the present invention to ensure a reliable supply of the DC-DC converter for the 12 V vehicle electrical system from the high-voltage vehicle electrical system or the high-voltage battery, which enables the use of a 12 V battery with a small capacity and a correspondingly small weight and space requirement or even the omission of this battery.

[0014] High-performance vehicles with powerful drives require larger-capacity batteries to achieve an acceptable range despite the higher available power. High-performance vehicles also increasingly use higher system voltages for the drive, e.g., 800 V, which enable higher drive motor power while still maintaining acceptable cross-sections of the electrical conductors. To charge large-capacity batteries in a reasonable timeframe, rapid or high-performance chargers, which apply high-voltage direct currents to the vehicle, are preferably used. The use of high voltages, among other things, minimizes ohmic losses in the charging cables and connectors, so that less energy is lost even at high charging power.

[0015] However, a higher system voltage in a vehicle also means that all electrical consumers operating at this system voltage, such as air conditioning compressors, DC-DC converters for the 12 V vehicle electrical system, heaters, chassis components, and the like, must be designed for this system voltage. However, since the majority of electric or partially electric vehicles use a system voltage of 400 V, this means that components for the higher system voltages require significantly more expensive custom designs.

[0016] In addition, due to the currently smaller number of high-performance chargers available, it is desirable to be able to charge vehicles with high system voltages at the considerably larger number of 400 V charging points. This generally requires that the vehicle's system voltage is reduced to 400 V for charging at a 400 V charging point. Since many electrically operated consumers must be fully functional both during charging at an 800 V high-performance charger and during charging at a 400 V charging point, and in addition, the battery voltage is not constant during charging, the input voltage at an electrical consumer can be reduced by up to 200 V in a 400 V system, as described above.can vary by up to 400 V in an 800 V system, these electrically operated consumers must be designed for a very wide operating voltage range of approximately 300 V to 900 V, which is not only complex and therefore expensive, but also results in reduced efficiency compared to a smaller operating voltage range.

[0017] It is therefore a further object of the present invention to provide a high-voltage vehicle electrical system which enables rapid charging of the high-voltage battery, possibly with two significantly different charging voltages, and also enables efficient operation of high-voltage electrical consumers during charging with a voltage which lies in the range of the lower of the different charging voltages. DESCRIPTION OF THE INVENTION

[0018] One or more of the above-mentioned objects are achieved by one or more of the patent claims. Advantageous further developments and embodiments are specified in the dependent claims.

[0019] A high-voltage vehicle electrical system according to the invention comprises a high-voltage battery and a first charger, which converts a single- or multi-phase alternating voltage applied to its input via a connection into a direct voltage and applies it to a high-voltage intermediate circuit. According to the invention, two bidirectionally operable DC-DC converters are connected to the high-voltage intermediate circuit. The two bidirectionally operable DC-DC converters are configured to individually or jointly charge the high-voltage battery from the high-voltage intermediate circuit or to supply the high-voltage intermediate circuit with a direct voltage from the high-voltage battery.

[0020] The high-voltage on-board power system according to this design provides a high voltage regulated within a narrow voltage range in the high-voltage intermediate circuit thanks to two DC-DC converters, which can be operated individually or in parallel, when the high-voltage intermediate circuit is powered by the high-voltage battery. This makes it possible to design the electrical consumers connected to the high-voltage intermediate circuit for a smaller input voltage range and thus operate them efficiently. Furthermore, the high-voltage intermediate circuit can be powered from one or both DC-DC converters, depending on the power requirements of the connected electrical consumers, allowing the high-voltage intermediate circuit to be operated or powered with greater efficiency at low loads.In addition, the high-voltage intermediate circuit can continue to be supplied with energy even if one of the DC-DC converters fails, so that a DC-DC converter connected to it, in particular, which supplies the 12 V on-board network from which safety-relevant systems are powered, can continue to operate safely. In addition, charging a high-voltage battery with just one battery bank from the high-voltage intermediate circuit can be faster using two DC-DC converters operated in parallel, as twice the charging current can be provided. And in the final phase of charging, one of the DC-DC converters can be switched off, enabling efficient operation here too. During charging, the first charger generates a high voltage in the high-voltage intermediate circuit that is regulated within a narrow voltage range, so that the consumers connected to the high-voltage intermediate circuit can continue to operate efficiently even during charging.

[0021] According to one embodiment, the high-voltage battery of the high-voltage on-board electrical system comprises two battery banks, which can be selectively connected in series or separated from each other by means of a switching device. Each of the two battery banks is assigned to one of the two bidirectionally operable DC-DC converters.

[0022] The high-voltage on-board electrical system of this design offers the option of charging the high-voltage battery particularly quickly with twice the charging voltage when the battery banks are connected in series via the switching device. By doubling the charging voltage, the battery can be charged with twice the charging power with the same charging current and the same losses in the supply line, which in practice almost halves the charging time. Such charging with twice the charging voltage is not carried out using the bidirectional DC-DC converters of the high-voltage on-board electrical system, but via a second, usually external vehicle charger, which can be connected directly to the terminals of the series-connected battery banks. The control of the charging with twice the voltage is also usually integrated into the second charger. Accordingly, the high-voltage on-board electrical system can be set up to be connected to the second charger, e.g.via a corresponding plug connection, so that the battery banks connected in series can be charged by the second charger. Thanks to the two DC-DC converters, which can be operated individually or in parallel, the high-voltage on-board electrical system of this design also provides a high voltage regulated within a narrow voltage range in the high-voltage intermediate circuit when the latter is fed from the high-voltage battery when the battery banks are connected in series by means of the switching device. The advantage of the higher reliability of the high-voltage intermediate circuit is also retained, as is the possibility of efficiently operating electrical consumers connected to the high-voltage intermediate circuit during charging using the second charger.

[0023] With battery banks separated from each other by the switching device, there are essentially two batteries, each with an associated bidirectionally operable DC-DC converter. In this configuration, each of the battery banks can be charged by the associated bidirectionally operable DC-DC converter from the high-voltage intermediate circuit fed by the first charger. In this way, all the advantages of the high-voltage on-board electrical system according to the invention can be achieved. In fact, this configuration even offers the additional advantage that if one battery bank fails, the high-voltage intermediate circuit can be fed from the other battery bank, so that the DC-DC converter for the 12 V on-board electrical system fed by the high-voltage intermediate circuit can continue to operate even if one battery bank fails.The resulting safety gains cannot be overestimated, as the failure of even a single battery cell, of which more than 100 can be connected in series, can lead to a total failure of the battery bank. This makes it easier to meet the high reliability requirements placed on safety systems in highly automated driving. The even greater safety gain compared to a high-voltage battery with a single battery bank with twice the voltage, where more than 200 cells can be connected in series, is easily apparent.

[0024] In addition to the aforementioned advantages during charging, the series connection of two battery banks during driving enables higher power with lower losses in the cables if the drive motor is fed directly from the battery. The electrical consumers supplied with electrical energy via the high-voltage intermediate circuit, on the other hand, can be effectively operated with the voltage provided by the bidirectionally operable DC-DC converter(s), which is regulated within a narrow voltage range. Accordingly, in one or more embodiments of the high-voltage on-board electrical system according to the invention, a drive motor of the vehicle is connected directly to the battery. For lower power requirements, the drive motor can also be connected directly to a battery bank or even to the high-voltage intermediate circuit.

[0025] In one or more embodiments of the high-voltage on-board power supply system according to the invention, a DC-DC converter is connected to the high-voltage intermediate circuit and reduces the voltage of the high-voltage intermediate circuit to a voltage that does not exceed the limit values ​​for voltage range I according to IEC 60449, for example to 12 V.

[0026] In one or more embodiments of the high-voltage on-board power supply system according to the invention, a high-voltage consumer is connected to the high-voltage intermediate circuit, for example a compressor of an air conditioning system or a heater.

[0027] A method for operating a high-voltage vehicle electrical system according to the invention comprises, in a first operating mode, operating one or both of the bidirectionally operable DC-DC converters such that a DC voltage from the high-voltage battery is fed into the high-voltage intermediate circuit. This operating mode can be selected, for example, while driving. In a second operating mode, the method comprises feeding a DC voltage into the high-voltage intermediate circuit by means of the first charger, and charging the high-voltage battery by means of one or both of the two bidirectionally operable DC-DC converters. In this case, electrical loads connected to the high-voltage intermediate circuit can be supplied with energy in the first and second operating modes.

[0028] In a high-voltage vehicle electrical system with a high-voltage battery, the two battery banks of which can be connected in series or separated from one another by means of a switching device, the method comprises, in a third operating mode, controlling the switching device such that the two battery banks are connected in series, and feeding a charging DC voltage into the battery using a second charger. Furthermore, one or both of the bidirectionally operable DC-DC converters are operated such that a DC voltage from one or both of the battery banks of the high-voltage battery is fed into the high-voltage intermediate circuit. This allows electrical consumers connected to the high-voltage intermediate circuit to be supplied with energy even in the third operating mode.

[0029] The method can be carried out in an electronic control unit which has one or more microprocessors, volatile and non-volatile memory as well as sensor inputs and control outputs which are operatively connected to components of the high-voltage vehicle electrical system.

[0030] A computer program product implementing the method contains instructions which, when executed by a processor of a control unit, cause the control unit to control a high-voltage vehicle electrical system connected to control outputs and signal inputs of the control unit in order to carry out one or more embodiments and further developments of the method described above.

[0031] The computer program product can be stored on a computer-readable medium or data carrier. The medium or data carrier can be physically embodied, e.g., as a hard drive, CD, DVD, flash memory, or the like, but the medium or data carrier can also comprise a modulated electrical, electromagnetic, or optical signal that can be received by a computer via a corresponding receiver and stored in the computer's memory.

[0032] The bidirectionally operable DC-DC converters of the high-voltage on-board power system according to the invention can ensure a stable voltage in the high-voltage intermediate circuit both during driving operation and during charging operation, in which the two battery banks are connected in series. This voltage can be lower than the voltage across the series connection of the battery banks, but can also be set to other values. The series voltage of the battery banks can be used directly for the drive if a particularly high drive power is required. Alternatively, especially for lower drive powers, the drive can also be supplied from the high-voltage intermediate circuit, with the DC-DC converters then supplying the required power. Since several DC-DC converters operate in parallel in this case, the drive power can be greater than the continuous power of a single DC-DC converter.Nevertheless, the high-voltage battery can be charged with 800 V on high-performance chargers, so that fast charging is possible.

[0033] Due to the stable voltage in the high-voltage intermediate circuit, which is preferably well below the system voltage of high-performance chargers, e.g., 400 V with a system voltage of the high-performance charger of 800 V, electrically operated consumers can be installed in the vehicle that are designed for the nominal voltage of a single battery bank, in particular electrical consumers that are used in a variety of electrically or partially electrically powered vehicles with a system voltage of 400 V. This eliminates the need to design electrical consumers for a very wide input voltage range and high operating voltages of 800 V and more, which enables the use of cheaper components.In fact, the high-voltage on-board network according to the invention even makes it possible to narrow the input voltage range of the electrical consumers due to the more stable voltage of the high-voltage intermediate circuit thanks to the control of the bidirectionally operable DC-DC converters compared to a battery bank directly connected to the high-voltage intermediate circuit, so that they can always be operated at or at least close to an operating point with optimal efficiency.

[0034] The bidirectional DC-DC converters can be integrated into the high-voltage battery so that only a DC voltage within a narrow fluctuation range is present at the connection between the high-voltage battery and the high-voltage intermediate circuit. SHORT DESCRIPTION OF THE DRAWING

[0035] The invention is described below with reference to the drawing. The drawing shows Fig. 1 a schematic block diagram of a first embodiment of an exemplary high-voltage vehicle electrical system according to the invention and components connected thereto, Fig. 2 a schematic block diagram of a second embodiment of an exemplary high-voltage on-board network according to the invention and components connected thereto, Fig. 3 a schematic block diagram of a third embodiment of an exemplary high-voltage on-board network according to the invention and components connected thereto, Fig. 4 a schematic block diagram of a fourth embodiment of an exemplary high-voltage on-board network according to the invention and components connected thereto, Fig. 5 a flowchart of an exemplary method according to the invention for the selective operation of a high-voltage vehicle electrical system in one of several different operating modes, and Fig. 6 a schematic block diagram of an exemplary control unit for carrying out the method according to the invention.

[0036] In the figures, identical or similar elements are referenced with the same reference numerals. DESCRIPTION OF EMBODIMENTS

[0037] Fig. 1 shows a schematic block diagram of a first embodiment of an exemplary high-voltage vehicle electrical system 100 according to the invention and components connected thereto. A first and a second bidirectional DC-DC converter 112a, 112b are connected in parallel to a high-voltage battery 102 and a high-voltage intermediate circuit 110. A drive motor 118 is also connected to the high-voltage battery 102. The bidirectionally operable DC-DC converters 112a, 112b can be operated separately or simultaneously. If one of the bidirectionally operable DC-DC converters 112a, 112b is not operated, the respective DC-DC converter behaves like an open switch, i.e., no current flows from the high-voltage battery 102 to the high-voltage intermediate circuit 110 or vice versa.A complete disconnection of the supply lines from the high-voltage battery 102 to the relevant DC-DC converter and / or from the DC-DC converter to the high-voltage intermediate circuit 110 can also occur when the DC-DC converter is not in operation. Also connected to the high-voltage intermediate circuit 110 are a DC-DC converter 114, which reduces the voltage of the high-voltage intermediate circuit 110 to a voltage that does not exceed the limit values ​​for voltage range I according to IEC 60449, e.g., 12 V, as well as an electrical load operated directly with the voltage of the high-voltage intermediate circuit, e.g., an air conditioning compressor or an auxiliary heater. Also connected to the high-voltage intermediate circuit 110 is a first charger 106, which converts a single-phase or multi-phase AC voltage applied to a terminal 108 into a DC voltage and feeds it into the high-voltage intermediate circuit 110.

[0038] When operating in a first mode, the Fig. 1 can be supplied with electrical energy from the high-voltage battery 102 via one or both of the bidirectionally operable DC-DC converters 112a, 112b. In a second operating mode, the high-voltage intermediate circuit 110 can be supplied with electrical energy via the charger 106, and the battery can be charged in the second operating mode via one or both of the bidirectionally operable DC-DC converters 112a, 112b. In both operating modes, the DC-DC converter 114 and the electrical load 116 can be operated as intended.

[0039] Fig. 2 shows a schematic block diagram of a second embodiment of an exemplary high-voltage vehicle electrical system 100 according to the invention and components connected thereto. Fig. The high-voltage electrical system 100 shown in Figure 2 is essentially identical to that shown in Fig. 1, however, the drive motor 118 is not connected directly to the high-voltage battery 102, but rather to the high-voltage intermediate circuit 110. Such a configuration can be advantageous if the drive motor 118 does not consume very high power, because a DC voltage with a comparatively small fluctuation range is present in the high-voltage intermediate circuit. This can be used for a more efficient design of the drive motor 118 and ensures consistent drive characteristics during driving operation across all charge states of the high-voltage battery 102. The bidirectionally operable DC-DC converters 112a, 112b must be designed accordingly to ensure that sufficient power is available to all components that must be operated during driving operation and are supplied with electrical energy from the high-voltage intermediate circuit 110.In order to compensate for short-term peaks in the power requirement of the drive motor 118, other components can be switched off briefly, e.g. air conditioning compressors during acceleration.

[0040] The high-voltage intermediate circuit 110 of the Fig. 2 can be used in both with reference to Fig. 1 explained operating modes.

[0041] Fig. 3 shows a schematic block diagram of a third embodiment of an exemplary high-voltage vehicle electrical system 100 according to the invention and components connected thereto. Fig. The high-voltage electrical system 100 shown in Figure 3 is essentially identical to that shown in Fig. 1, however, the high-voltage battery 102 has two battery banks 102a, 102b, which can be selectively connected in series with one another or separated from one another by means of a switching device 104. In addition, each of the two battery banks 102a, 102b is assigned one of the two bidirectionally operable DC-DC converters 112a, 112b. The drive motor 118 is connected via the series-connected battery banks 102a, 102b and can thus be operated with a voltage twice as high as the drive motor 118 of the Fig. 1. This allows the drive motor 118 to be provided with a higher power output at the same maximum current and thus the same maximum losses in the supply lines, thereby enabling higher driving performance.

[0042] When operating in a first mode, the Fig. 3 can be supplied with electrical energy via one or both of the bidirectionally operable DC-DC converters 112a, 112b from one or both of the battery banks 102a, 102b of the high-voltage battery 102, which are connected in series in this operating mode by means of the switching device 104.

[0043] In a second operating mode, the Fig. 3 can be supplied with electrical energy via the charger 106, and each of the battery banks 102a, 102b of the battery 102 can be charged in the second operating mode via the associated bidirectionally operable DC-DC converter 112a, 112b, regardless of whether the battery banks 102a and 102b are separated from one another by the switching device 104 or connected in series. Alternatively, the battery banks 102a, 102b can each be charged alternately by the associated bidirectionally operable DC-DC converter 112a or 112b.

[0044] In a third operating mode, a second charger (not shown in the figure) is connected to terminals (not shown in the figure) at the positive pole of the battery bank 102a and at the negative pole of the battery bank 102b, and the battery banks 102a, 102b are connected in series by means of the switching device 104, so that the battery 102 can be charged with a charging voltage which is approximately twice as high as the voltage of the high-voltage intermediate circuit 110. The battery can thus be charged with a higher power and thus faster, without the charging losses increasing due to higher currents.

[0045] In each of the operating modes, the DC-DC converter 114 and the electrical load 116 can be operated as intended.

[0046] Fig. Figure 4 shows a schematic block diagram of a fourth embodiment of an exemplary high-voltage electrical system 100 according to the invention and components connected thereto. In contrast to the Fig. 3, the drive motor 118 is not directly connected to the battery 102, but to the high-voltage intermediate circuit 110. Although this does not allow the use of a drive motor with a higher power, as is the case with the high-voltage on-board network 100 shown in the Fig. 3, the advantage of faster charging remains. As an alternative to supplying the drive motor 118 from the high-voltage intermediate circuit 110, the latter can of course also be selectively connected to one of the battery banks 102a, 102b by means of a corresponding switching device not shown in the figure, whereby switching between the two battery banks can be performed, for example, based on their charge levels.

[0047] The high-voltage intermediate circuit 110 of the Fig. 4 shown high-voltage electrical system 100 can be used in all with reference to Fig. 3 explained operating modes.

[0048] Fig. 5 shows a flowchart of an exemplary method 200 for selectively operating a high-voltage vehicle electrical system 100 according to the invention in one of several different operating modes. In step 202, an operating mode is first selected. If the first operating mode is selected, the method branches to step 204, in which the high-voltage intermediate circuit 110 is fed from the battery 102 via one or both bidirectional DC-DC converters 112a, 112b. If the second operating mode is selected, the method branches to step 206, in which a charging voltage from the first charger 106 is fed into the high-voltage intermediate circuit 110. In step 208, the high-voltage battery 102 is then charged from the high-voltage intermediate circuit 110 via one or both bidirectional DC-DC converters 112a, 112b.If the battery 102 has two battery banks 102a, 102b that can be connected in series or separated from one another via a switching device, the switching device 104 can, if necessary, be controlled in an optional step 207 to separate the two battery banks 102a and 102b from one another. If the third operating mode is selected, the method branches to step 210, in which the switching device 104 is controlled to connect the two battery banks 102a, 102b of the high-voltage battery 102 in series, and in step 212, a charging voltage from a second charger is applied directly to the battery 102.Meanwhile, the high-voltage intermediate circuit 110 is supplied with electrical energy by one or both of the bidirectionally operable DC-DC converters 112a, 112b from one or both battery banks 102a, 102b, so that electrical loads connected thereto can also be operated during charging, indicated in the figure by the arrow from step 210 to step 204.

[0049] Fig.6 shows a schematic block diagram of an exemplary control unit 300 for implementing method 200. A microprocessor 302, volatile memory 304, non-volatile memory 306, and control outputs or sensor inputs 308 are communicatively connected to one another via one or more data lines or buses 310. The non-volatile memory 306 contains computer program instructions which, when executed by the microprocessor 302 in the volatile memory 304, configure the control unit 300 to control a high-voltage vehicle electrical system 100 for executing one or more embodiments of method 200.

Claims

[1] High-voltage on-board power supply system (100) of a vehicle with a high-voltage battery (102) and a first charger (106), which converts a single-phase or multi-phase alternating voltage applied to its input via a connection (108) into a direct voltage regulated within a narrow voltage range and applies it to a high-voltage intermediate circuit (110), wherein two bidirectionally operable direct-voltage converters (112a, 112b) are connected in parallel to one another to the high-voltage intermediate circuit (110), which are designed, in a second operating mode, to charge the high-voltage battery (102) individually or jointly from the high-voltage intermediate circuit (110), and, in a first operating mode, to feed the high-voltage intermediate circuit (110) individually or jointly with a direct voltage from the high-voltage battery (102), wherein a high-voltage consumer (116) is connected to the high-voltage intermediate circuit (110) is. [2] High-voltage on-board network (100) according to claim 1,characterized by in that the high-voltage battery (102) comprises two battery banks (102a, 102b), wherein a switching device (104) is provided which selectively connects the two battery banks (102a, 102b) in series with one another or separates them from one another, wherein each of the two battery banks (102a, 102b) is assigned to one of the two bidirectionally operable DC-DC converters (112a, 112b). [3] High-voltage on-board network (100) according to claim 2, characterized by that a second charger can be connected to the two battery banks (102a, 102b) of the high-voltage battery (102) connected in series to one another by means of the switching device (104) in such a way that the battery banks (102a, 102b) connected in series to one another can be charged by the second charger. [4] High-voltage on-board network (100) according to one of the preceding claims, characterized bythat a DC-DC converter (114) is connected to the high-voltage intermediate circuit (110), which reduces the voltage of the high-voltage intermediate circuit (110) to a voltage that does not exceed the limit values ​​for the voltage range I according to IEC 60449. [5] High-voltage on-board network (100) according to one of the preceding claims, characterized by that a drive motor (118) of the vehicle is connected directly to the high-voltage battery (102) or to the high-voltage intermediate circuit (110).

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