Power supply system for a vehicle and method for controlling a power supply system for a vehicle

Abstract

The invention relates to a power supply system (1, 1', 1'') for an electric vehicle, comprising a first alternating voltage connection (1a) and a second alternating voltage connection (1b), which are designed to be connected to an AC voltage source. Furthermore, the power supply system (1, 1', 1'') comprises a power converter arrangement (1000) with a symmetrical power converter circuit (10, 10', 10'') with power factor correction, wherein the power converter circuit (10, 10', 10'') is connected via at least one first input terminal (10a) to the first alternating voltage connection (1a) and via at least one second input terminal (10b) to the second alternating voltage connection (1b), and is designed to convert the alternating voltage applied between the first alternating voltage terminal (1a) and the second alternating voltage terminal (1b) into a first DC voltage (U2a) applied between a first output terminal (11a) of the power converter circuit (10, 10', 10'') and a centre terminal (30), and into a second DC voltage (U2b) applied between a second output terminal (11b) of the power converter circuit (10, 10', 10'') and the centre terminal (30), and also comprises a first capacitor (31) connected between the first output terminal (11a) and a centre terminal (30), and a second capacitor (32) connected between the second output terminal (10b) and the centre terminal (30). The power supply system (1, 1', 1'') is further designed to supply a load (50), which is connected between the first alternating voltage terminal (1a) and the centre terminal (30), with a predetermined alternating voltage during a charging process in which the first alternating voltage terminal (1a) and the second alternating voltage terminal (1b) are connected to an external voltage source.

Description

[0001] Description

[0002] Title for a vehicle and method for controlling a for a vehicle

[0003] The present invention relates to a power supply system for a vehicle and a method for controlling a power supply system for a vehicle as well as a computing unit and a computer program for carrying out the same.

[0004] Background of the invention

[0005] In integrated chargers (so-called on-board chargers) for electric vehicles (fully electric or hybrid), the AC voltage from the grid is converted into DC voltage to charge the electric vehicle's traction battery. For example, the on-board charger can have a two-stage design. The first stage can be a rectifier, which can be equipped with power factor correction (PFC) to rectify the input AC voltage in phase. The second stage can be a DC-DC converter to convert the rectified input voltage into the battery voltage of the traction battery. Alternatively, single-stage designs are also possible, combining both functions in a single rectifier stage.

[0006] On-board chargers can be operated either in regions with three-phase AC grids (e.g., 22 kW in the EU and China) or in regions with single-phase AC grids (e.g., North America and Japan). Furthermore, the nominal voltage of the single-phase AC grid in North America can be an AC voltage with an amplitude of 120 V or 240 V, depending on the power capacity of the connection.

[0007] On-board chargers are still intended to provide alternating current for a vehicle socket as an additional function (vehicle-to-load, V2L). In some vehicles, this function only needs to be provided when the vehicle is not in charging mode. In a bidirectional design of rectifier and DC-DC converter, the hardware installed for charging can provide this function (possibly with additional components for protection / monitoring). In other vehicles, however, the function should also be available during charging.

[0008] Disclosure of the invention

[0009] According to the invention, a power supply system for a vehicle and a method for controlling a power supply system for a vehicle, as well as a computing unit and a computer program for implementing the same, are proposed, having the features of the independent patent claims. Advantageous embodiments are the subject of the dependent claims and the following description.

[0010] The invention is based on a power supply system for a vehicle, which has a first AC voltage terminal and a second AC voltage terminal, which are configured to be connected to an AC voltage source via which the vehicle can be supplied with an AC voltage. Furthermore, the power supply system comprises a power converter arrangement with a symmetrical power converter circuit, which is connected to the first AC voltage terminal via a first input terminal and to the second AC voltage terminal via a second input terminal.The power converter circuit is configured to convert the AC voltage applied to the first AC voltage terminal and the second AC voltage terminal into a first DC voltage and a second DC voltage, wherein the first DC voltage is applied between a first output terminal of the power converter circuit and a center terminal, and the second DC voltage is applied between a second output terminal of the power converter circuit and the center terminal. The first and second DC voltages are, in particular, polarized oppositely to one another. The power converter arrangement further comprises a first capacitor connected between the first output terminal and the center terminal, and a second capacitor connected between the second output terminal and the center terminal.

[0011] The core of the invention is that, thanks to the symmetrical design of the rectifier of the power converter circuit with a center terminal, an additional AC voltage is provided or regulated between the first AC voltage terminal and the center terminal in addition to the input voltage. This voltage can be supplied from the power system as the vehicle-to-load voltage.

[0012] In detail, the power supply system is designed to supply a load, in particular a load connected to a socket of the vehicle, such as an electrical consumer, which is connected between the first AC voltage connection and the middle connection, with a predetermined AC voltage during a charging process in which the power supply system is connected to the external AC voltage source via the AC voltage connections. The voltage level of the middle connection is set for this purpose by modulating the AC voltage applied to the first AC voltage connection and the AC voltage applied to the second AC voltage connection. During the charging process, in particular a traction battery of the vehicle is also charged using the first DC voltage and / or second DC voltage.

[0013] This allows the vehicle-to-load function to be provided during charging without the need for additional components, thus reducing manufacturing costs. Furthermore, the voltage provided as vehicle-to-load voltage can be set to a specified voltage, for example, an AC voltage of 120 V, by adjusting the voltage level of the center terminal, independent of the mains connection.

[0014] In addition, the symmetrical design of the rectifier eliminates the need for an unfolding circuit, which switches between the positive and negative DC potentials at zero crossing, thus causing disadvantages in terms of common-mode emissions and insulation clearances of the rectifier. This saves manufacturing costs and reduces maintenance and repair work.

[0015] In one embodiment, the power converter circuit comprises a plurality of first input terminals, each of the first input terminals being connected to the first AC voltage terminal. Furthermore, the power converter circuit comprises a plurality of second input terminals, each of the second input terminals being connected to the second AC voltage terminal. This allows the power supply system to be connected to a two-phase AC voltage source. The use of two first input terminals and two second input terminals is particularly preferred. This allows the power supply system to be optionally connected to a three-phase AC voltage source.

[0016] In one embodiment, the power supply system further comprises a third AC voltage terminal and a fourth AC voltage terminal configured to be connected to the external AC voltage source. The power converter circuit of the power supply system further comprises two first input terminals and two second input terminals. The power converter arrangement further comprises a first changeover switch and a second changeover switch.The first changeover switch is arranged between the two first input terminals, the first AC voltage terminal and the third AC voltage terminal and is configured to, when the power supply system is connected to a two-phase external AC voltage source, connect the two first input terminals to the first AC voltage terminal, and, when the power supply system is connected to a three-phase external AC voltage source, connect one of the two first input terminals to the first AC voltage terminal and connect the other of the two first input terminals to the third AC voltage terminal.Similarly, the second changeover switch is arranged between the two second input terminals, the second AC voltage terminal and the fourth AC voltage terminal and is configured to, when the power supply system is connected to a two-phase external AC voltage source, connect the two second input terminals to the second AC voltage terminal, and, when the power supply system is connected to a three-phase external AC voltage source, connect one of the two second input terminals to the second AC voltage terminal and connect the other of the two second input terminals to the fourth AC voltage terminal.The power supply system is configured such that an alternating voltage of a two-phase alternating voltage source is applied, in particular, between the first and third alternating voltage terminals, and an alternating voltage of a three-phase alternating voltage is applied to the four alternating voltage terminals. The first and second changeover switches are further configured, in particular, to detect whether a two-phase or three-phase alternating voltage is applied and to automatically establish the corresponding connection between the alternating voltage terminals and the input terminals.

[0017] This allows the power system to be connected to both a two-phase and a three-phase AC voltage source without the need for additional components in the converter circuit. This, in particular, reduces the manufacturing costs of the power system.

[0018] In one embodiment, the power converter arrangement further comprises at least one first inductance, each arranged between one of the at least one first input terminal of the power converter circuit and the AC voltage terminal to which the respective first input terminal is connected, and at least one second inductance, each arranged between one of the at least one second input terminal of the power converter circuit and the AC voltage terminal to which the respective second input terminal is connected. This means that if the power converter circuit has only a first and a second input terminal, a first inductance and a second inductance are present.The first inductance is connected between the first input terminal and the first AC voltage terminal, while the second inductance is connected between the second input terminal and the second AC voltage terminal. If, however, the power converter circuit has, for example, two first input terminals and two second input terminals, which are each connected to the first AC voltage terminal or the second AC voltage terminal or the first to fourth AC voltage terminals, two first inductances and two second inductances are used. The two first inductances are arranged in particular behind the changeover switch, at which the connection to the first AC voltage terminal is divided between the two first input terminals, so that only one first inductance is arranged between each of the first input terminals and the first AC voltage terminal.The same applies to the second inductors. If the power supply system further comprises a third and fourth AC voltage terminal and two first and two second input terminals, wherein one of the first input terminals is connected to the first AC voltage terminal and the other of the first input terminals is connected to the third AC voltage terminal, and one of the second input terminals is connected to the second AC voltage terminal and the other of the second input terminals is connected to the fourth AC voltage terminal, a first inductor is arranged between each of the first input terminals and the corresponding AC voltage terminal, and a second inductor is arranged between each of the second input terminals and the corresponding AC voltage terminal. The at least one first inductor and / or the at least one second inductor can be coils, for example.By using inductors, the ripple of the respective input voltage and thus the ripple of the output voltage can be reduced and the power factor can be improved.

[0019] In one embodiment, the power converter circuit further comprises at least one first controllable semiconductor switching element arranged between one of the at least one first input terminal and the first output terminal, and at least one second controllable semiconductor switching element arranged between the same one of the at least one first input terminal and the second output terminal. Furthermore, the power converter circuit comprises at least one third controllable semiconductor switching element arranged between one of the at least one second input terminal and the first output terminal, and at least one fourth controllable semiconductor switching element arranged between the same one of the at least one second input terminal and the second output terminal.If the power converter circuit has a single first input terminal and a single second input terminal, the power converter circuit also comprises a single first to fourth controllable semiconductor switching element. If there is more than one first and / or second input terminal, the number of first and second controllable semiconductor switching elements corresponds to the number of first input terminals, and a first and second controllable semiconductor switching element is connected to exactly one of the first input terminals. The same applies to the third and fourth controllable semiconductor switching elements.

[0020] This provides a simple symmetrical power converter circuit that generates two DC voltages from an applied AC voltage, which are applied between an output terminal and the center terminal.

[0021] In one embodiment, the power converter circuit further comprises a center output terminal connected to the center terminal, and additionally a fifth controllable semiconductor switching element and a sixth controllable semiconductor switching element connected in series between one of the at least one first input terminal and the center terminal, and / or a seventh controllable semiconductor switching element and an eighth controllable semiconductor switching element connected in series between one of the at least one second input terminal and the center terminal.

[0022] By using the additional semiconductor switching elements connected to the center terminal, the shape of the DC voltage can be further improved, which in particular eliminates the need for additional filters to smooth the DC voltage.

[0023] The invention further relates to a vehicle comprising a charging port configured to connect the vehicle to an external AC voltage source, and a power supply system according to one of the preceding claims, wherein the first AC voltage port and the second AC voltage port of the power supply system are connected to corresponding ports of the charging port. In the case of a three-phase AC voltage, both the charging port and the power supply system have four ports. The four ports of the charging port are connectable to the ports of the external AC voltage source, and each of the four AC voltage ports of the power supply system is connectable to the corresponding port of the charging port.

[0024] The invention further relates to a method for operating a power supply system as presented in the preceding embodiments, wherein in the method the voltage level of the center connection is controlled such that a predetermined alternating voltage is applied to the load. The voltage level of the center connection is controlled in particular by modulating the alternating voltage applied to the first alternating voltage connection and / or the alternating voltage applied to the second alternating voltage connection. A downstream adjustment of the voltage level of the center connection is preferably carried out by means of a downstream DC / DC converter, the input of which is connected to the center tap. A computing unit according to the invention, e.g. a control device of a power supply system, is set up, in particular in terms of programming, to carry out a method according to the invention.

[0025] The implementation of a method according to the invention in the form of a computer program or computer program product with program code for carrying out all method steps is also advantageous, since this entails particularly low costs, in particular if an executing control unit is also used for other tasks and is therefore already present. Finally, a machine-readable storage medium is provided with a computer program stored thereon, as described above. Suitable storage media or data carriers for providing the computer program are, in particular, magnetic, optical, and electrical memories, such as hard disks, flash memories, EEPROMs, DVDs, and others. Downloading a program via computer networks (Internet, intranet, etc.) is also possible. Such a download can be wired or cable-based or wireless (e.g., via a WLAN network, a 3G, 4G, 5G, or 6G connection, etc.).

[0026] Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings.

[0027] The invention is illustrated schematically in the drawing using exemplary embodiments and is described below with reference to the drawing.

[0028] Short description of the drawings

[0029] Figure 1 shows a power supply system according to an embodiment of the invention,

[0030] Figure 2 shows a power supply system according to a further embodiment of the invention, Figure 3 shows a power supply system according to a further embodiment of the invention,

[0031] Figure 4 shows a power converter circuit that can be used in a power supply system according to an embodiment of the invention, and

[0032] Figure 5 shows a power converter circuit that can be used in a power supply system according to another embodiment of the invention.

[0033] Embodiment(s) of the invention

[0034] Figure 1 shows a power supply system 1 according to an embodiment of the invention. The power supply system 1 comprises a first AC voltage connection 1a and a second AC voltage connection 1b, via which the power supply system 1 can be connected to an external AC voltage source. The external AC voltage source can be, for example, a single-phase AC voltage source.

[0035] The power supply system 1 further comprises a power converter arrangement 1000 with a power converter circuit 10. The power converter circuit 10 has a first input terminal 10a and a second input terminal 10b. The first input terminal 10a is conductively connected to the first AC voltage terminal 1a of the power supply system 1, and the second input terminal 10b is conductively connected to the second AC voltage terminal 1b of the power supply system 1. A first inductor 21 is connected between the first AC voltage terminal 1a and the first input terminal 10a. A second inductor 22 is connected between the second AC voltage terminal 1b and the second input terminal 10b. The inductors 21, 22 serve to reduce the ripple of the AC voltage present between the AC voltage terminals 1a, 1b.The power converter circuit 10 further has a first output terminal 11a and a second output terminal 11b, via which the power converter circuit 100 outputs a first DC voltage U2a and a second DC voltage U2b. A first capacitor 31 and a second capacitor 32 are connected in series between the first output terminal 11a and the second output terminal 11b, and have a center terminal 30 between the first capacitor 31 and the second capacitor 32. The first DC voltage U2a can be tapped between a first DC voltage terminal 100a of the power converter arrangement 1000 and the center terminal 30, while the second DC voltage U2b can be tapped between a second DC voltage output terminal 100b of the power converter arrangement 1000 and the center terminal 30.

[0036] Furthermore, a load 50 is arranged between the first AC voltage terminal 1a and the center terminal 30. The AC voltage U0 is applied to the load 50. The load 50 can be, for example, an electrical device, such as a refrigerator, connected to a socket located, for example, inside the vehicle.

[0037] The AC voltage U0 applied to the load 50 can be adjusted, in particular, by modulating the AC voltage applied to the first AC voltage terminal 1a and / or the second AC voltage terminal 1b. This allows the AC voltage applied to the load 50 to always have a predetermined amplitude, for example, 120 V, regardless of the amplitude of the input voltage, which in North America can be 120 V or 240 V, for example.

[0038] Figure 2 shows a power supply system T according to a further embodiment of the invention. Like reference numerals denote like components, so a detailed explanation is omitted and reference is made to the explanations for Figure 1.

[0039] In contrast to the power converter circuit 10 of Figure 1, the power converter circuit 10' of Figure 2 has two first input terminals 10a and two second input terminals 10b, each of the first input terminals 10a being connected to the first AC voltage terminal 1a and each of the second input terminals being connected to the second AC voltage terminal 1b. A first inductor 21 is connected between each of the first input terminals 10a and the first AC voltage terminal 1a. Furthermore, a second inductor 22 is also connected between each of the second input terminals 10b and the second AC voltage terminal 1b.

[0040] In addition, the power converter circuit 10' has a center output terminal 11c connected to the center terminal 30. This allows the power converter circuit 10' to be additionally connected to the voltage level of the center terminal 30.

[0041] In the case of a three-phase AC voltage source, as shown in Figure 3, the power supply system 1" has, in addition to the first AC voltage terminal 1a and the second AC voltage terminal 1b, a third AC voltage terminal 1c and a fourth AC voltage terminal 1d. The two first input terminals 10a and the two second input terminals 10b are not connected in parallel to the first AC voltage terminal 1a and the second AC voltage terminal 1b, respectively, but each of the input terminals 10a, 10b of the power converter circuit 10 is connected to one of the four AC voltage terminals. The third AC voltage terminal 1c and the fourth AC voltage terminal 1d enable the power supply system 1" to be connected to a three-phase AC voltage source.

[0042] One of the first input terminals 10a is connected to the first AC voltage terminal 1a and the other first input terminal 10a is connected to the third AC voltage terminal 1c, while one of the two second input terminals 10b is connected to the second AC voltage terminal 1b and the other second input terminal 10b is connected to the fourth AC voltage terminal 1d. Furthermore, a first inductance 21 is connected between each of the first input terminals 10a and the corresponding AC voltage terminal 1a, 1c to which the first input terminal 10a is connected. Similarly, a second inductance 22 is connected between each of the second input terminals 10b and the corresponding AC voltage terminal 1b, 1d to which the second input terminal 10b is connected.

[0043] For this purpose, no further components are required in the power converter arrangement 1000'. Instead, one of the two first input terminals 10a is connected to the first AC voltage terminal 1a and the other of the two first input terminals 10a is connected to the third AC voltage terminal 1c. Furthermore, one of the two second input terminals 10b is connected to the second AC voltage terminal 1b and the other of the two second input terminals 10b is connected to the fourth AC voltage terminal 1d. This connection can be effected by a suitable first changeover switch 41 and a suitable second changeover switch 42, wherein, in the case of a single-phase AC voltage, the first changeover switch 41 connects the two first input terminals 10a to the first AC voltage terminal 1a and the second changeover switch 42 connects the two second input terminals 10b to the second AC voltage terminal 1b.For a three-phase AC voltage, the first changeover switch 41 connects one of the two first input terminals 10a to the first AC voltage terminal 1a and the other of the two first input terminals 10a to the third AC voltage terminal 1c, while the second changeover switch 42 connects one of the two second input terminals 10b to the second AC voltage terminal 1b and the other of the two second input terminals 10b to the fourth AC voltage terminal 1d. The first changeover switch 41 and the second changeover switch 42 can, in particular, operate automatically.

[0044] Figure 4 shows a power converter circuit 10 that can be used in a power supply system 1, T, 1" according to an embodiment of the invention. In particular, this power converter circuit 10 can be used in the power supply system 1 shown in Figure 1. For this purpose, the power converter circuit 10, 10' has a first controllable semiconductor switching element 12a and a second controllable semiconductor switching element 12b, both of which are connected to the first input terminal 10a. The first controllable semiconductor switching element 12a is further connected to the first output terminal 11a, while the second controllable semiconductor switching element 12b is connected to the second output terminal 11b. In addition, the power converter circuit 10 has a third controllable semiconductor switching element 13a and a fourth controllable semiconductor switching element 13b.The third controllable semiconductor switching element 13a is connected to the second input terminal 10b and the first output terminal 11a, and the fourth third controllable semiconductor switching element 13b is connected to the second input terminal 10b and the second output terminal 11b.

[0045] By means of the symmetrical converter circuit 10 thus presented, a first and a second direct voltage can be generated when an alternating voltage is applied between the first input terminal 10a and the second input terminal 10b.

[0046] The interconnection of the terminals of the power converter circuit 10, 10' shown in Figure 4 could also be used in the power converter arrangement 1000' of Figure 2 or 3. For this purpose, a first and second, or third and fourth, controllable semiconductor switching element 12a, 12b, 13a, 13b would be used for each of the first input terminals 10a and each of the second input terminals 10b. Furthermore, the center output terminal 11c would be omitted, or it would not be connected to any of the input terminals 10a, 10b.

[0047] Figure 5 shows a power converter circuit 10" which can be used in a power supply system 1, T, 1" according to a further embodiment of the invention.

[0048] In contrast to the power converter circuit 10 as shown in Figure 4, the power converter circuit 10" further comprises a center output terminal 11c, via which the power converter circuit 10" can be connected to the center terminal 30, which is arranged between the first capacitor 31 and the second capacitor 32.

[0049] In addition to the first to fourth controllable semiconductor switching elements 12a, 12b, 13a, 13b, the power converter circuit 10" has a fifth controllable semiconductor switching element 12c and a sixth controllable semiconductor switching element 12d. The fifth and sixth controllable semiconductor switching elements 12c, 12d are connected in series between the first input terminal 10a and the center output terminal 11c. Furthermore, the power converter circuit 10" comprises a seventh controllable semiconductor switching element 13c and an eighth controllable semiconductor switching element 13d, which in turn are connected in series between the second input terminal 10b and the center output terminal 11c. The fifth and sixth controllable semiconductor switching elements 12c, 12d and the seventh and eighth controllable semiconductor switching elements 13c, 13d are connected in series in such a way that no current can flow unintentionally between the first input terminal 10a orthe second input terminal 10b and the center output terminal 11c. This means that if the controllable semiconductor switching elements are, for example, MOSFETs, the current flow through a single controllable semiconductor switching element can only be blocked in one direction, since the body diode of the MOSFET is conductive in the other direction. By arranging two controllable semiconductor switching elements in series, current flow can be prevented by connecting the controllable semiconductor switching elements in such a way that the directions in which the body diodes can conduct current are opposite to one another (so-called back-to-back connection). A corresponding functionality can equally be realized with individual bidirectionally blocking switching elements, for example GaN switching elements.Accordingly, the fifth and sixth controllable semiconductor switching elements 12c, 12d or the seventh and eighth controllable semiconductor switching elements 13c, 13d could each be replaced by a bidirectional switching element.

[0050] The power converter circuit 10" could, for example, be used in the power supply system 1 shown in Figure 1. For this purpose, the power converter circuit 10 shown in Figure 1 would only have to have a center output terminal 10c, which can be connected to the center terminal 30.

[0051] If the power converter circuit 10" is to be installed in the power supply system T, 1" of Figure 2 or 3, the circuit shown would have to be used once for each pair of the first input terminal 10a and the second input terminal 10b. In this case, this would mean that the power converter circuit 10" shown would be present twice.

Claims

Claims 1. A power supply system (1, T, 1") for an electric vehicle, comprising: a first AC voltage terminal (1a) and a second AC voltage terminal (1b) adapted to be connected to an AC voltage source, and a power converter arrangement (1000), the power converter arrangement (1000) comprising: - a symmetrical power converter circuit (10, 10', 10") with power factor correction, wherein the power converter circuit (10, 10', 10") is connected to the first AC voltage terminal (1a) via at least one first input terminal (10a) and to the second AC voltage terminal (1b) via at least one second input terminal (10b) and is configured to convert the AC voltage present between the first AC voltage terminal (1a) and the second AC voltage terminal (1b) into a first DC voltage (U2a), which is present between a first output terminal (11a) of the power converter circuit (10) and a center terminal (30), and a second DC voltage (U2b), which is present between a second output terminal (11b) of the power converter circuit (10, 10', 10") and the center terminal (30), - a first capacitor (31) connected between the first output terminal (11a) and the center terminal (30), and - a second capacitor (32) connected between the second output terminal (10b) and the center terminal (30), wherein the power supply system (1, T, 1") is designed to supply a load (50) connected between the first AC voltage terminal (1a) and the center terminal (30) during a charging process in which the power supply system (1, T, 1") is connected to the external AC voltage source with a specified AC voltage.

2. Power supply system (T) according to claim 1, wherein the power converter circuit (10') comprises: a plurality of first input terminals (10a), each of the plurality of first input terminals (10a) being connected to the first AC voltage terminal (1a), and a plurality of second input terminals (10b), each of the plurality of second input terminals (10b) being connected to the second AC voltage terminal (1b).

3. Power supply system (1") according to claim 1 or 2, wherein the power supply system (1") further comprises: a third AC voltage terminal (1c) and a fourth AC voltage terminal (1d) which are adapted to be connected to an AC voltage source, wherein the power converter circuit (10') has two first input terminals (10a) and two second input terminals (10b), and wherein the power converter arrangement (1000') further comprises: a first changeover switch (41) which is arranged between the two first input terminals (10a), the first AC voltage terminal (1a) and the third AC voltage terminal (1c) and is adapted, when the power supply system (1") is connected to a two-phase external AC voltage source, to connect the two first input terminals (10a) to the first AC voltage terminal (1a), and,when the power supply system (1") is connected to a three-phase external AC voltage source, to connect one of the two first input terminals (10a) to the first AC voltage terminal (1a) and to connect the other of the two first input terminals (10a) to the third AC voltage terminal (1c), and a second changeover switch (42) arranged between the two second input terminals (10b), the second AC voltage terminal, (1b) and the fourth AC voltage terminal (1d) and is configured to, when the power supply system (1") is connected to a two-phase external AC voltage source, connect the two second input terminals (10b) to the second AC voltage terminal (1b), and, when the power supply system (1") is connected to a three-phase external AC voltage source, connect one of the two second input terminals (10b) to the second AC voltage terminal (1b) and connect the other of the two second input terminals (10b) to the fourth AC voltage terminal (1d).

4. Power supply system (1, T, 1") according to one of the preceding claims, wherein the power converter arrangement (1000, 1000') further comprises: - at least one first inductance (21) arranged between one of the at least one first input terminal (10a) of the converter circuit (10') and the AC voltage terminal (1a, 1c) to which the respective first input terminal (10a) is connected, and - at least one second inductance (22) which is arranged between one of the at least one second input terminal (10b) of the power converter circuit (10') and the AC voltage terminal (1b, 1d) to which the respective second input terminal (10b) is connected.

5. Power supply system (1, T, 1") according to one of the preceding claims, wherein the power converter circuit (10, 10', 10") further comprises: - at least one first controllable semiconductor switching element (12a) arranged between one of the at least one first input terminal (10a) and the first output terminal (11a), - at least one second controllable semiconductor switching element (12b) arranged between the at least one first input terminal (10a) and the second output terminal (11b), - at least one third controllable semiconductor switching element (13a) arranged between one of the at least one second input terminal (10b) and the first output terminal (11a), and - at least one fourth controllable semiconductor switching element (13b) arranged between the same of the at least one second input terminal (10b) and the second output terminal (11b).

6. Power supply system (1, T, 1") according to the preceding claim, wherein the power converter circuit (10', 10") further comprises: a center output terminal (11c) connected to the center terminal (30), a fifth controllable semiconductor switching element (12c) and a sixth controllable semiconductor switching element (12d) connected in series between one of the at least one first input terminal (11a) and the center terminal (10c), and / or a seventh controllable semiconductor switching element (13c) and an eighth controllable semiconductor switching element (13d) connected in series between one of the at least one second input terminal (11b) and the center terminal (10c).

7. A vehicle comprising a charging port configured to connect the vehicle to an external AC voltage source, and a power supply system (1, T, 1") according to any one of the preceding claims, wherein each of the AC voltage terminals (1a, 1b, 1c, 1d) of the power supply system (1, T, 1") is connected to corresponding terminals of the charging port.

8. A method for operating a power supply system (1, T, 1") according to one of claims 1 to 6, the method comprising: Controlling (S100) the voltage level of the center terminal (30) so that a predetermined alternating voltage is applied to the load (50).

9. Method according to the preceding claim, wherein the voltage level of the center terminal (30) is determined by modulating the voltage at the first AC voltage applied to the AC voltage terminal (1a) and / or the AC voltage applied to the second AC voltage terminal (1b).

10. A computing unit configured to carry out all method steps of a method according to one of claims 8 or 9.

11. A computer program which causes a computing unit to carry out all method steps of a method according to one of claims 8 or 9 when it is executed on the computing unit.

12. A machine-readable storage medium having stored thereon a computer program according to the preceding claim.

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