DC charging distribution unit and DC charging system including same

Abstract

The invention relates to a DC charging distribution unit (UU1). Comprising a first primary side terminal (UU1F1) for receiving a first input current from a power unit (PU, PU1, PU2), a secondary side DC vehicle connection terminal (UU1S2) connectable to the vehicle to provide a vehicle charging current (id1), a first secondary side power sharing terminal (UU1S3) connectable to another DC charging distribution unit to provide a sharing current to the other DC charging distribution unit, and a current distributor (S1; S2) operable to select between a vehicle charging configuration and a power sharing configuration; a vehicle charging configuration (S1-1, S1-2, S1-3) in which the first input current is used to feed a vehicle charging current to the secondary DC vehicle connection terminal (UU1S2); in the power sharing configuration, the first input current is used to feed a sharing current to the first secondary power sharing terminal.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to DC charging distribution units, in particular to DC charging distribution units for charging electric vehicles, and to DC charging systems comprising such DC charging distribution units. BACKGROUND

[0002] DC charging power at a charging site, for example in an electric vehicle (EV) charging station, is distributed to on-site power outlets. Traditionally, in a “one-piece” charger type, a power unit located at a distance from the power outlets is connected via a DC link or DC cable to a distribution unit or user unit where the power outlets are located. In an alternative traditional configuration of the “split system” type, one central power unit feeds multiple user units. Each user unit is connected via a separate DC link to the central power unit and each user unit is distributed by a switching matrix within the power unit.

[0003] The traditional units and systems lack flexibility, in particular when adapting the on-site power outlets to an increased or decreased demand. It is desirable to have a more flexible DC charging distribution configuration. SUMMARY

[0004] According to an aspect of the present disclosure, a DC charging distribution unit comprises a first primary side terminal, a secondary side DC vehicle connection terminal, a first secondary side power sharing terminal, and a current distributor. The first primary side terminal is configured to receive a first input current from a power unit. The secondary side DC vehicle connection terminal is connectable to a vehicle and is configured to provide a vehicle charging current. The first secondary side power sharing terminal is connectable to another DC charging distribution unit for providing a shared current to the other DC charging distribution unit. The current distributor is operable to select between a vehicle charging configuration and a power sharing configuration. In the vehicle charging configuration, the first input current is used to feed the vehicle charging current to the secondary side DC vehicle connection terminal. In the power sharing configuration, the first input current is used to feed the shared current to the first secondary side DC power sharing terminal.

[0005] According to another aspect of the present disclosure, a DC charging system comprises at least one power unit, and at least a first and a second charging distribution unit as disclosed herein. For example, the first and second distribution units are adjacent distribution units. Each power unit comprises at least one power terminal. The distribution units are each spaced apart from the power units by at least a first distance. Adjacent ones of the distribution units are spaced apart from each other by at most a second distance. Adjacent ones of the distribution units are connected to each other at their secondary side power sharing terminals via a first secondary side link. At least one primary side terminal of the first and second distribution units is connected to a power terminal of the at least one power unit via a primary side link.

[0006] As used herein, a power unit is generally a device connected to an electrical grid, such as a public AC grid. A typical power unit is configured to receive AC power from an AC grid at its primary side, convert it to DC power, and output the DC power at its primary side, and / or vice versa. A power unit typically comprises power electronics and thus can occupy a relatively large space. Typically, a power unit is installed at a location where the surrounding conditions are favorable, e.g. accessibility of the grid, connectivity to the grid, available space, cooling conditions, etc. A power unit is typically located at a distance from a location where a vehicle is to be charged, e.g. a parking lot, and the surrounding conditions for placing a power unit will be less favorable.

[0007] As used herein, a DC charging distribution unit is generally located at a distance from a power unit. A DC charging distribution unit can be relatively small compared to a power unit.

[0008] Throughout the specification, a DC charging distribution unit can be abbreviated as distribution unit, and / or can also be referred to as a user unit, as its location is relatively close to a user or operator of a vehicle, who connects to the distribution unit in order to charge a battery of the vehicle.

[0009] As used herein, charging is understood as an illustrative term, not a limiting term. Charging can include a flow of power (current) in a direction from the distribution unit towards a vehicle connected to a secondary side DC vehicle connection terminal, or in a direction from the secondary side DC vehicle connection terminal towards the distribution unit. Furthermore, charging can also include supplying power to a vehicle for purposes other than increasing a state of charge (SoC) of a battery of the vehicle, e.g. power consumed by on-board equipment. Furthermore, charging can include supplying power to a vehicle, which power is only indirectly used for increasing the SoC of the battery.

[0010] As used herein, a primary side DC terminal is generally any type of connectivity establishing or connectivity enabling component that enables reception of a first input current. This can include a plug / socket connection, but hardwiring of the primary side terminal is also possible. A connection to a secondary side of a power unit can be established via the primary side terminal to receive power output by the power unit, i.e. a current at a certain voltage (first input current).

[0011] As used herein, a secondary side DC vehicle connection terminal is generally any type of connectivity establishing or connectivity enabling component that enables reception of a vehicle charging current, and typically includes a plug / socket connection. As used herein, a secondary side DC power sharing terminal is generally any type of connectivity establishing or connectivity enabling component that enables reception of a vehicle charging current, and can include a plug / socket connection or a hardwired connection.

[0012] In embodiments, the distribution unit comprises a second secondary side power sharing terminal. The second secondary side power sharing terminal is connected to (optionally internally connected to) the first primary side terminal. The second secondary side power sharing terminal can be connected to a further charging distribution unit. In this way, input power can be obtained from the second secondary side power sharing terminal, i.e. from the further charging distribution unit. This enables cascading of distribution units at their secondary sides for power exchange.

[0013] In embodiments, the distribution unit comprises a second primary side terminal for receiving a second input current from a power unit. The power unit can be the same as the power unit from which the first input current is received, or it can also be different. The current distributor is operable to further select between a combined input configuration and a separate input configuration. In the combined input configuration, the first and second primary side terminals are combined. Typically, the combined input switch configuration can be used for both the vehicle charging configuration and the power sharing configuration. In the separate input configuration, the first and second primary side terminals are disconnected from each other. Typically, the separate input configuration can be used for the vehicle charging configuration, wherein the first primary side terminal, but not the second primary side terminal, is connected to the secondary side DC vehicle connection terminal. Further, typically, the separate input configuration can be used for the separate power sharing configuration, wherein the second primary side terminal, but not the first primary side terminal, is connected to the first secondary side power sharing terminal. This can help to increase flexibility even further.

[0014] The switch is configured to galvanically insulate the secondary side DC vehicle connection terminal (UU1S2) from the first secondary side DC power sharing terminal (UU1S3) in any switch position.

[0015] Typically, in the vehicle charging switch configuration, the secondary side DC vehicle connection terminal (UU1S2) and the first primary side DC terminal (UU1F1) are disconnected from the first secondary side DC power sharing terminal (UU1S3) to galvanically insulate the secondary side DC vehicle connection terminal (UU1S2) from the first secondary side DC power sharing terminal (UU1S3).

[0016] Typically, in the power sharing switch configuration, the first primary side DC terminal (UU1F1) is disconnected from the secondary side DC vehicle connection terminal (UU1S2) to galvanically insulate the secondary side DC vehicle connection terminal (UU1S2) from the first secondary side DC power sharing terminal (UU1S3).

[0017] In embodiments, the distribution unit further comprises a power converter. The power converter is configured to convert the first and / or second input current into a vehicle charging current and / or a sharing current. The power converter can help to increase flexibility, e.g. to adapt it to one or both of DC and AC input power.

[0018] In embodiments, the first and / or second input current is a DC current. Then, the current distributor can be configured as a switch assembly, the vehicle charging configuration is a vehicle charging switch configuration, and the power sharing configuration is a power sharing switch configuration. In the vehicle charging switch configuration, the first primary side terminal is connected to the secondary side DC vehicle connection terminal. In the power sharing configuration, the first primary side terminal is connected to the first secondary side power sharing terminal.

[0019] In embodiments, where the first and / or second input current is a DC current, the current distributor can be configured as a switch assembly, the vehicle charging configuration is a vehicle charging switch configuration, and the power sharing configuration is a power sharing switch configuration, as described above, the separate input configuration comprises a vehicle charging configuration, in which the first primary side terminal, but not the second primary side terminal, is connected to the secondary side DC vehicle connection terminal, and a separate power sharing configuration, in which the second primary side terminal, but not the first primary side terminal, is connected to the first secondary side power sharing terminal.

[0020] In embodiments, in a DC charging system as described herein, wherein the maximum vehicle charging current at the secondary side DC vehicle connection terminal of the first distribution unit is less than or equal to the sum of the current carrying capacity of the primary side link of the first user unit and the current carrying capacity of the secondary side link between the first user unit and the second user unit.

[0021] Generally, the current carrying capacity is directly related to the maximum power that can be delivered at a certain link voltage. Especially in case the primary side DC link and the switch assembly are used as current distributor, as described herein, the voltage between the primary side DC link and the secondary side terminal is generally the same, and the current carrying capacity can be considered as the power exchange capacity at this voltage level.

[0022] In embodiments, the DC charging system as described herein comprises a third distribution unit. The distribution units are connected to each other via respective secondary side DC links (SSL1, SSL2) at their secondary side power sharing terminals. The maximum first vehicle charging current at the secondary side DC vehicle connection terminal of the first distribution unit is less than or equal to the sum of the current carrying capacity of the primary side DC links of the first to third user units. The current carrying capacity of the secondary side DC link between the first distribution unit and the second distribution unit and the current carrying capacity of the secondary side DC link between the second distribution unit and the third distribution unit are designed to be at least said sum.

[0023] In embodiments, one or more of the secondary side links are series connection links. In a series connection configuration, the first secondary side power sharing terminal of a distribution unit is used as a power output terminal and the third secondary side power sharing terminal of another distribution unit is used as a power input terminal. For example, the first secondary side power sharing terminal of a first distribution unit is connected to the third secondary side power sharing terminal of a second distribution unit, the first secondary side power sharing terminal of the first distribution unit is used as a power output terminal, and the third secondary side power sharing terminal of the second distribution unit is used as a power input terminal. For example, the first secondary side power sharing terminal of a second distribution unit is connected to the third secondary side power sharing terminal of a third distribution unit, the first secondary side power sharing terminal of the second distribution unit is used as a power output terminal, and the third secondary side power sharing terminal of the third distribution unit is used as a power input terminal. In this way, the distribution units can be cascaded in series.

[0024] In embodiments, in a DC charging system as described herein, the first secondary side power sharing terminal of each distribution unit is connected to the second secondary side power sharing terminal of its respective adjacent distribution unit.

[0025] In embodiments, one or more of the secondary side links are parallel connection links. In a parallel connection configuration, the first secondary side power sharing terminal of a distribution unit is connected to the first secondary side power sharing terminal of another distribution unit. For example, the first secondary side power sharing terminal of a first distribution unit is connected to the first secondary side power sharing terminal of a second distribution unit. For example, the first secondary side power sharing terminal of a second distribution unit is connected to the first secondary side power sharing terminal of a third distribution unit. In this way, the distribution units can be combined in parallel.

[0026] In embodiments, in a DC charging system as described herein, the first secondary side power sharing terminal of each distribution unit and its respective adjacent distribution unit are connected to each other via a respective secondary side link. BRIEF DESCRIPTION OF DRAWINGS

[0027] FIGS. 1 and 2 each illustrate a configuration of a conventional DC charging system.

[0028] Figures 3a to 4b Each illustrates an exemplary configuration of a DC charging distribution unit according to embodiments.

[0029] Figures 5 to 10 Each illustrates an exemplary configuration of a DC charging system using the DC charging distribution units described herein. DETAILED DESCRIPTION

[0030] The technology is described below with reference to the drawings, in which exemplary embodiments of aspects are illustrated. The claimed invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Like reference numerals refer to like elements throughout. The description of the drawings is therefore not detailed for each figure. It should also be noted that the figures are intended to facilitate understanding of the embodiments. They are not intended to be exhaustive or limit the scope of the claimed invention. Furthermore, the illustrated embodiments need not have all the aspects or advantages shown. Aspects or advantages described in conjunction with a particular embodiment aspect can be practiced in the context of other embodiments, even if not so illustrated, or even if not so explicitly described. Features, functions, and advantages can be implemented independently of each other or can be combined in various embodiments.

[0031] Before describing several exemplary embodiment aspects illustratively depicted in the figures, a general introduction is provided to further understanding. One of the key challenges for electric vehicle (EV) charging is to distribute the available power between the sockets (charging terminals) at the site.

[0032] One conventional solution is an all-in-one charger, where the power electronics are located within the user unit. Each conventional all-in-one charger receives input power from a separately distributed power unit. The input power is typically AC input power. The all-in-one charger converts the input power to the desired DC power via the built-in power electronics and supplies the converted DC power to the charging terminals.

[0033] Another conventional solution is a split-system type charger, where one centralized power unit feeds multiple user units and the power is distributed through a switching matrix inside the power unit. The switching matrix inside the power unit is relatively complex. Wiring is required between the centralized power unit and each user unit. This wiring needs to be rated for full load current. The system cannot deliver this current on all outputs simultaneously.

[0034] As an example, FIG. 1 illustrates a conventional charging system 1000 including a power unit PU, a first user unit UUl, and a second user unit UU2. The power unit PU includes power modules PM1 through PM8. Each power module PM1...PM8 is assigned to a corresponding power terminal PT1...PT8. For example, each power module PM1...PM8 has a power rating of 100 kW. A 4x4 switch matrix SW1000 selectively bridges some of the power terminals PT1...PT8 of the power unit PU. The user unit UUl is connected to the switch matrix SW1000 via a 600 ampere (A) bus. The user unit UUl is also connected to the switch matrix SW1000 via another 600 A bus. The user unit UU2 is connected to the switch matrix SW1000 via a 600 ampere (A) bus. The user unit UU2 is also connected to the switch matrix SW1000 via another 600 A bus. The buses are rated for full load current. For example, for an exemplary distance dl = 50 m between the power unit PU and each user unit UUl, UU2, the 600 A buses each have a wiring gauge of 240 mm 2 . Thus, at least 800 meters of 240 mm 2 gauge wiring is required: 50 m x 2 (per pole) x 2 (for DC+ and DC-) x 4 (outlets).

[0035] As another example, FIG. 2 illustrates another conventional charging system 2000 including a first power unit PU1, a second power unit PU2, a first user unit UUl, and a second user unit UU2. The power unit PU1 includes power modules PM1 through PM8. Each power module PM1...PM8 is assigned to a corresponding power terminal PT1...PT8. For example, each power module PM1...PM8 has a power rating of 100 kW. The power unit PU2 includes power modules PM1 through PM8. Each power module PM1...PM8 is assigned to a corresponding power terminal PT1...PT8. For example, each power module PM1...PM8 has a power rating of 100 kW. A 2x2 switch matrix SW2000 selectively bridges some of the power terminals PT1...PT8 of the power unit PU1 and some of the power terminals PT1...PT8 of the power unit PU2. The user unit UUl is connected to the switch matrix S2000 via a 1500 ampere (A) bus. The user unit UU2 is connected to the switch matrix S2000 via a 1500 A bus. For example, for an exemplary distance dl = 50 m between each power unit PU1, PU2 and each user unit UUl, UU2, the 1500 A buses each have a wiring gauge of 300 mm 2 . Thus, at least 800 meters of 300 mm 2Wiring: 50m × 4 (per pole) × 2 (for DC+ and DC-) × 2 (sockets).

[0036] Based on the above general understanding, embodiments for charging distribution units and charging systems using those units are described below.

[0037] Figure 3a A schematic configuration of a DC charging distribution unit UU1 according to an embodiment is shown. The terminal UU1F1 on the first side or primary side of the distribution unit UU1 is configured to receive a first input current (e.g., from the power unit) from the power unit. Figure 5 (As shown). Terminal UU1F1 is also called the first primary side terminal. Terminal UU1S2 on the second side or secondary side of the distribution unit UU1 is configured to be connected to the vehicle ( Figure 3a (Not shown in the image) to provide vehicle charging current. Terminal UU1S2 is also called the secondary-side DC vehicle connection terminal. The secondary-side terminal UU1S3 is configured to connect to another DC charging distribution unit (…). Figure 3a (Not shown in the image), used to provide shared current to another DC charging distribution unit. Terminal UU1S3 is also called the first secondary side power sharing terminal.

[0038] Figure 3a The distribution unit UU1 includes current distributors S1-1 and S1-2. Current distributors S1-1 and S1-2 are operable to select between a vehicle charging configuration and a power sharing configuration. In the vehicle charging configuration of current distributors S1-1 and S1-2, a first input current received at the first primary-side terminal UU1F1 is used to feed vehicle charging current to the secondary-side DC vehicle connection terminal UU1S2. Note that feeding the secondary-side DC vehicle connection terminal UU1S2 is not limited to vehicle charging current and may optionally include other currents. In the power sharing configuration of current distributors S1-1 and S1-2, a first input current received at the first primary-side terminal UU1F1 is used to feed shared current to the first secondary-side power sharing terminal UU1S3.

[0039] exist Figure 3a In the example, the distribution unit UU1 is specifically configured to receive DC current as the first input current at the first primary terminal UU1F1. According to this configuration, the current distributor includes a first switch S1-1 and a second switch S1-2. Switches S1-1 and S1-2 can be collectively referred to as a switch assembly. Figure 3a The vehicle charging configuration in the example is a vehicle charging switch configuration, wherein the first primary-side terminal UU1F1 is connected to the secondary-side DC vehicle connection terminal UU1S2. Furthermore, Figure 3a The power sharing configuration in the example is a power sharing switch configuration, wherein the first primary side terminal UU1F1 is connected to the first secondary side power sharing terminal UU1S3.

[0040] It is worth noting that, in Figure 3a In the examples, the vehicle charging switch configuration may be active while the power sharing switch configuration may be inactive; or the power sharing switch configuration may be active while the vehicle charging switch configuration may be inactive; or both the vehicle charging switch configuration and the power sharing switch configuration may be active simultaneously.

[0041] When the vehicle charging switch configuration is active and the power sharing switch configuration is inactive, the vehicle charging current is the first input current. In other words, the secondary DC vehicle connection terminal UU1S2 directly feeds the first input current as the vehicle charging current via the first switch S1-1 of the switch assembly.

[0042] When the power sharing switch is active and the vehicle charging switch is inactive, the shared current is the first input current. In other words, the first secondary power sharing terminal UU1S3 directly feeds the first input current as the shared current via the second switch S1-2 of the switch assembly.

[0043] When both the vehicle charging switch configuration and the power sharing switch configuration are active, the first input current is distributed via the first switch S1-1 and the second switch S1-2 to both the secondary DC vehicle connection terminal UU1S2 and the first secondary power sharing terminal UU1S3.

[0044] Figure 3a The exemplary distribution unit UU1 also includes a second secondary-side power sharing terminal UU1S1. Note that the second secondary-side power sharing terminal UU1S1 is optional, and the distribution unit UU1 is not necessarily equipped with a second secondary-side power sharing terminal UU1S1. When the second secondary-side power sharing terminal UU1S1 is present, it is connected (optionally internally connected) to the first primary-side terminal UU1F1. The second secondary-side power sharing terminal UU1S1 can be connected to another DC charging distribution unit ( Figure 3a (Not shown in the image). When connected to another DC charging distribution unit, the distribution unit UU1 obtains input power from that DC charging distribution unit via the second secondary power sharing terminal UU1S1.

[0045] In one example, such as Figure 3a As shown, multiple distribution units UU1 can be cascaded in such a way that the first secondary-side power sharing terminal UU1S3 of the current distribution unit UU1 is connected to the second secondary-side power sharing terminal UU1S1 of the subsequent distribution unit UU1. That is, the distribution unit UU1 can be part of a modular configuration.

[0046] Figure 3bA schematic configuration of a DC charging distribution unit UU1 according to an embodiment is shown. The terminal UU1F1 on the first side or primary side of the distribution unit UU1 is configured to receive a first input current (e.g., from the power unit) from the power unit. Figure 5 (As shown). Terminal UU1F1 is also called the first primary side terminal. Terminal UU1S2 on the second side or secondary side of the distribution unit UU1 is configured to be connected to the vehicle ( Figure 3b (Not shown in the image) to provide vehicle charging current. Terminal UU1S2 is also called the secondary-side DC vehicle connection terminal. The secondary-side terminal UU1S3 is configured to connect to another DC charging distribution unit (…). Figure 3b (Not shown in the image), used to provide shared current to the other DC charging distribution unit. Terminal UU1S3 is also called the first secondary side power sharing terminal.

[0047] Figure 3b The distribution unit UU1 includes components collectively referred to as current distributors PC1, S1-1, and S1-2. The power converter PC is connected on its primary side to a first primary-side terminal UU1F1. The power converter PC is connected on its secondary side to a first switch S1-1 leading to the secondary-side DC vehicle connection terminal UU1S2 and a second switch S1-2 leading to the first secondary-side power-sharing terminal UU1S3. The current distributors PC, S1-1, and S1-2 are operable to select between a vehicle charging configuration and a power-sharing configuration. In the vehicle charging configuration of the current distributors PC, S1-1, and S1-2, a first input current received at the first primary-side terminal UU1F1 is used to feed vehicle charging current to the secondary-side DC vehicle connection terminal UU1S2. That is, the first input current is converted into vehicle charging current via the power converter PC, and the converted current is routed to the secondary-side DC vehicle connection terminal UU1S2 via the first switch S1-1. Note that the secondary-side DC vehicle connection terminal UU1S2 is not limited to the vehicle charging current and may optionally include other currents. In the power-sharing configuration of the current distributor PC, S1-1, S1-2, the first input current received at the first primary-side terminal UU1F1 is used to feed the shared current to the first secondary-side power-sharing terminal UU1S3. That is, the first input current is converted into a shared current via the power converter PC, and the converted current is routed to the first secondary-side power-sharing terminal UU1S3 via the second switch S1-2. Typically, the power converter PC outputs a DC current on its secondary side as the vehicle charging current and a DC current as the shared current.

[0048] exist Figure 3bIn the example, the distribution unit UU1 is specifically configured to receive AC current as the first input current at the first primary terminal UU1F1. According to this configuration, the current distributor includes a power converter, a first switch S1-1, and a second switch S1-2. Switches S1-1 and S1-2 can be collectively referred to as a switch assembly. Figure 3b The vehicle charging configuration in the example is a configuration where the first primary-side terminal UU1F1 is connected to the secondary-side DC vehicle connection terminal UU1S2 via a power converter PC. Furthermore, Figure 3b The power sharing configuration in the example is that the first primary-side terminal UU1F1 is connected to the first secondary-side power sharing terminal UU1S3 via the power converter PC.

[0049] It is worth noting that, in Figure 3b In the examples, the vehicle charging configuration may be active while the power sharing configuration is inactive; or the power sharing configuration may be active while the vehicle charging configuration is inactive; or both the vehicle charging configuration and the power sharing configuration may be active simultaneously.

[0050] Figure 3b The exemplary distribution unit UU1 also includes a second secondary-side power sharing terminal UU1S1. Note that the second secondary-side power sharing terminal UU1S1 is optional, and the distribution unit UU1 is not necessarily equipped with a second secondary-side power sharing terminal UU1S1. When the second secondary-side power sharing terminal UU1S1 is present, it is connected (optionally internally connected) to the first primary-side terminal UU1F1. Therefore, the current received at the second secondary-side power sharing terminal UU1S1 is input to the primary side of the power converter PC. The second secondary-side power sharing terminal UU1S1 may be connected to another DC charging distribution unit ( Figure 3b (Not shown in the image). When connected to another DC charging distribution unit, the distribution unit UU1 receives input power from the other DC charging distribution unit via the second secondary side power sharing terminal UU1S1. For example, this input power from the other DC charging distribution unit is AC input power.

[0051] However, it is worth noting that a configuration can be adopted in which the second secondary-side power sharing terminal UU1S1 is connected (optionally internally connected) to the secondary side of the power converter PC. This configuration is advantageous when the input power from another DC charging distribution unit is DC input power.

[0052] In one example, such as Figure 3b As shown, multiple distribution units UU1 can be cascaded in such a way that the first secondary-side power sharing terminal UU1S3 of the current distribution unit UU1 is connected to the second secondary-side power sharing terminal UU1S1 of the subsequent distribution unit UU1. That is, the distribution unit UU1 can be part of a modular configuration.

[0053] Figure 4a A distribution unit UU1 according to an embodiment is shown. The configuration of the distribution unit UU1 is similar to the configuration of the distribution unit UU1 in Figure 3a In the distribution unit UU1 in Figure 4a there is a second primary side terminal UU1F2 for receiving a second input current from a power unit. For example, the power unit providing the second input current is different from the power unit providing the first input current. Figure 4a The current distributors S1-1, S1-2, S1-3 of the distribution unit UU1 in Figure 3a are configured in a similar way as the current distributors S1-1 and S1-2 of the distribution unit UU1 in Figure 4a That is, the current distributors S1-1, S1-2, S1-3 of the distribution unit UU1 in Figure 3a are operable to select between a vehicle charging configuration and a power sharing configuration, as described in connection with Figure 4a Furthermore, the current distributors S1-1, S1-2, S1-3 of the distribution unit UU1 in

[0054] In the combined input configuration, the first and second primary side terminals are combined. Typically, the combined input configuration can be used for both the vehicle charging configuration and the power sharing configuration. In the example of Figure 4a the combined input configuration can be achieved by closing the third switch S1-3 of the current distributors to bridge the first and second primary side terminals UU1F1, UU1F2.

[0055] In the separate input configuration, the first and second primary side terminals UU1F1, UU1F2 are disconnected from each other. Typically, the separate input configuration can be used for the vehicle charging configuration, wherein the first primary side terminal UU1F1, but not the second primary side terminal UU1F2, is connected to the secondary side DC vehicle connection terminal UU1S2. Additionally or alternatively, the separate input configuration can be used for the separate power sharing configuration, wherein the second primary side terminal UU1F2, but not the first primary side terminal UU1F1, is connected to the first secondary side power sharing terminal.

[0056] Figure 4b A distribution unit UU1 according to an embodiment is shown. The configuration of the distribution unit UU1 is similar to the configuration of the distribution unit UU1 in Figure 3b In the distribution unit UU1 in Figure 4a there is a second primary side terminal UU1F2 for receiving a second input current from a power unit. For example, the power unit providing the second input current is different from the power unit providing the first input current. Figure 4b The distribution unit UU1 in comprises components collectively referred to as current distributors PC1, PC2, S1-1, S1-2, S1-3. Figure 4bThe current distributors PC1, PC2, S1-1, S1-2, S1-3 of the distribution unit UU1 in Figure 3b are configured in a similar manner as the current distributors PC, S1-1, and S1-2 of the distribution unit UU1 in Figure 4b . That is, Figure 3b The current distributors PC1, PC2, S1-1, S1-2, S1-3 of the distribution unit UU1 in Figure 4a are further operable to select between a combined input configuration and a separate input configuration.

[0057] The first power converter PC1 has its primary connected to a first primary terminal UU1F1 and a second secondary power sharing terminal UU1S1. The first power converter PC1 has its secondary connected to a first switch S1-1 leading to a secondary DC vehicle connection terminal UU1S2 and to a third switch S1-3 leading to the secondary of a second power converter PC2. The primary of the second power converter PC2 is connected to a second primary input terminal UU1F2. The current distributors PC1, PC2, S1-1, S1-2, S1-3 are operable to select between a vehicle charging configuration and a power sharing configuration. In the vehicle charging configuration of the current distributors PC, S1-1, S1-2, one or more of the first input current received on the first primary terminal UU1F1 and the input current received on the second secondary power sharing terminal UU1S1 are used to feed a vehicle charging current to the secondary DC vehicle connection terminal UU1S2.

[0058] That is, the input current(s) is converted via the power converter PC1 into a vehicle charging current, and the converted current is routed via the first switch S1-1 to the secondary DC vehicle connection terminal UU1S2. Note that the feeding of the secondary DC vehicle connection terminal UU1S2 is not limited to the vehicle charging current, and can optionally include other currents. In the power sharing configuration of the current distributor PC1, PC2, S1-1, S1-2, S1-3, the first input current received on the first primary terminal UU1F1 is used to feed a sharing current to the first secondary power sharing terminal UU1S3. That is, the first input current is converted via the power converter PC1 into a sharing current, and the converted current is routed via the third switch S1-3 and the second switch S1-2 to the first secondary power sharing terminal UU1S3. Typically, the power converter PC1 outputs at its secondary side a DC current as vehicle charging current as well as a DC current as sharing current. Additionally or alternatively, the second power converter PC2 converts the second input current received at the second primary terminal UU1F2 and outputs at its secondary side a DC current as vehicle charging current as well as a DC current as sharing current. By operating the switches S1-1, S1-2, S1-3, a suitable switching configuration for the operation is achieved.

[0059] In the example of Figure 4b , the distribution unit UU1 is specifically configured to receive an AC current on the first and / or second primary terminal UU1F1, UU1F2 as the first input current and / or the second input current. According to such a configuration, the current distributor comprises the power converters PC1, PC2, the first switch S1-1, the second switch S1-2 and the third switch S1-3. The switches S1-1, S1-2, S1-3 can be collectively referred to as a switching assembly.

[0060] In the combined input configuration, the currents from the first and second primary terminals are converted by the power converters PC1, PC2 individually, and then their respective outputs are combined. Typically, the combined input configuration can be used for both the vehicle charging configuration and the power sharing configuration. In the example of Figure 4b , the combined input configuration is achieved by closing the third switch S1-3 of the current distributor to bridge the secondary sides of the first and second power converters PC1, PC2.

[0061] In the separate input configuration, the first and second primary terminals UU1F1, UU1F2 are disconnected from each other. Typically, the separate input configuration can be used in a vehicle charging configuration, where the converted current from the first primary terminal UU1F1 but not the second primary terminal UU1F2 is routed to the secondary DC vehicle connection terminal UU1S2. Additionally or alternatively, the separate input configuration can be used in a separate power sharing configuration, where the converted current from the second primary terminal UU1F2 but not from the first primary terminal UU1F1 is routed to the first secondary power sharing terminal.

[0062] Figure 5 An exemplary DC charging system 100 according to an embodiment is shown. The system comprises a power unit PU. The power unit comprises power modules PM1...PM8. For example and without limitation, each power module PM1...PM8 has a rated output of 100 kW DC. The output of each power module PM1...PM8 is directly accessible via a corresponding output terminal PT1...PT8. In this example, and without limitation, every two adjacent output terminals are bridged to obtain a higher output. That is, PT1 is bridged to PT2, PT3 is bridged to PT4, and so on.

[0063] The system 100 further comprises a first DC charging distribution unit UU1 and a second DC charging distribution unit UU2. The configuration of the distribution unit UU1 is similar to Figure 3a the cascade of two distribution units shown and described in Figure 4a . That is, in the distribution unit UU1, the secondary terminal UU1S3 and the secondary terminal UU1S4 are bridged. Note that the physical distance between the secondary terminal UU1S3 and the secondary terminal UU1S4 is very short. The configuration of the distribution unit UU2 is similar to Figure 3a the cascade of two distribution units shown and described in Figure 4a . That is, in the distribution unit UU2, the secondary terminal UU2S3 and the secondary terminal UU2S4 are bridged. Note that the physical distance between the secondary terminal UU2S3 and the secondary terminal UU2S4 is very short.

[0064] The distribution unit UU1 is connected at its first primary side terminal UU1 F1 and via a primary side link FSL11 to the bridged output terminals PT1, PT2. The distribution unit UU1 is connected at its second primary side terminal UU1 F2 and via another primary side link FSL12 to the bridged output terminals PT3, PT4. The distribution unit UU2 is connected at its first primary side terminal UU2 F1 and via another primary side link FSL21 to the bridged output terminals PT5, PT6. The distribution unit UU2 is connected at its second primary side terminal UU2 F2 and via another primary side link FSL22 to the bridged output terminals PT7, PT8. The physical distance between the power unit PU and each distribution unit UU1, UU2 is denoted by d1. Note that the distance d1 between the power unit PU and each distribution unit UU1, UU2 is not necessarily exactly the same, but the distance d1 is typically in a similar range.

[0065] The distribution unit UU1 is connected at its secondary side power sharing terminal UU1 S6 and via a secondary side link SSL1 to the secondary side power sharing terminal UU2 S1 of the distribution unit UU2. The physical distance between the distribution units UU1, UU2 is denoted by d2. d2 is typically much larger than the physical distance between the secondary side terminal UU1 S3 and the secondary side terminal UU1 S4 or the physical distance between the secondary side terminal UU2 S3 and the secondary side terminal UU2 S4, and shorter than the distance d1. As a non-limiting example, d1 is for example 50 m, and d2 is for example 3 m.

[0066] The vehicle V1 is connected to the secondary side vehicle charging terminal UU1 S2. Similarly, the vehicle V2 is connected to the secondary side vehicle charging terminal UU2 S5. The vehicle V1 receives a charging current id1 from the distribution unit UU1. The vehicle V2 receives a charging current id2 from the distribution unit UU2. As used herein, charging is understood as an illustrative term, but not a limiting term. Charging can include a flow of power (current) in a direction from the distribution units UU1, UU2 towards the vehicles V1, V2 and / or in a direction from the vehicles V1, V2 towards the distribution units UU1, UU2. Furthermore, charging can also include supplying power to the vehicles V1, V2 for purposes other than increasing a state of charge (SoC) of a vehicle battery, for example power consumed by on-board equipment. Furthermore, charging can include supplying power to the vehicles V1, V2 which is only indirectly used for increasing the SoC of a battery, for example by intermediation of an on-board (vehicle-bound or vehicle-internal) power distributor.

[0067] According to an embodiment of the present specification, Figure 5 The use case of the example of Fig. 1 is comparable to the use case of the conventional example described above in connection with Fig. 1. In Figure 5In the example of FIG. 1, very short bridges between every two terminals PT1...PT8 of the power unit, between the secondary power sharing terminals UU1S3 and UU1S4 of the distribution unit UU1, and between the secondary power sharing terminals UU2S3 and UU2S4 of the distribution unit UU2 are each rated for maximum power, but since they are relatively short, they contribute little to overall system complexity and cost. In an example, the maximum power corresponds to a current of 1000 A. For example, the primary side links FSL11, FSL12, FSL21, FSL22 are each rated for 500 A. The secondary side link SSL1 is rated for 250 A, and can help with power sharing between the distribution unit UU1 and the distribution unit UU2. For example, for an exemplary distance dl = 50 m between the power unit PU and each of the user units UU1, UU2, the 500 A buses each have a wiring gauge of 185 mm 2 . Thus, at least 800 meters of 185 mm 2 gauge wiring is required: 50 m x 2 (per pole) x 2 (for DC+ and DC-) x 4 (outlets). The secondary side link SSL1 requires an additional 250 A wiring, but since the distance d2 is much shorter than dl, it contributes little to the overall complexity and wiring cost of the secondary side link SSL1. Thus, compared to the conventional configuration shown in FIG. 1, Figure 5 the configuration shown in the exemplary embodiment of FIG. 2 can help save cost and reduce complexity.

[0068] Figure 6 An exemplary DC charging system 100 according to an embodiment is shown. The system includes a first power unit PU1 and a second power unit PU2. Each power unit PU1, PU2 includes power modules PM1...PM8. For example and without limitation, each power module PM1...PM8 has a rated output of 100 kW DC. The output of each power module PM1...PM8 is directly accessible via a corresponding output terminal PT1...PT8. In this example, and without limitation, the output terminals of the power unit PU1 are bridged for higher output. Likewise, without limitation, the output terminals of the power unit PU2 are bridged for higher output.

[0069] The system 100 also includes a first DC charging distribution unit UU1 and a second DC charging distribution unit UU2. The configuration of the distribution unit UU1 is similar to the distribution unit shown and described in Figure 3a . The configuration of the distribution unit UU2 is similar to the distribution unit shown and described in Figure 3a .

[0070] The distribution unit UU1 is connected at its first primary side terminal UU1 F1 and via a primary side link FSL11 to the bridged output terminals PT1...PT8 of the power unit PU1. The distribution unit UU2 is connected at its first primary side terminal UU2 F1 and via another primary side link FSL12 to the bridged output terminals PT1...PT8 of the power unit PU2. The physical distance between the power unit PU1 and the distribution unit UU1 and the physical distance between the power unit PU2 and the distribution unit UU2 are each denoted by d1. Note that the distance d1 between the power units PU1, PU2 and the corresponding distribution units UU1, UU2 is not necessarily exactly the same, but the distance d1 is typically in a similar range.

[0071] The distribution unit UU1 is connected at its secondary side power sharing terminal UU1 S3 and via a secondary side link SSL1 to the secondary side power sharing terminal UU2 S1 of the distribution unit UU2. The physical distance between the distribution units UU1, UU2 is denoted by d2. d2 is typically much larger than the physical distance between the secondary side terminals UU1 S3 and UU1 S4 or between the secondary side terminals UU2 S3 and UU2 S4 and shorter than the distance d1. As a non-limiting example, d1 is for example 50 m and d2 is for example 3 m.

[0072] The vehicle V1 is connected to the secondary side vehicle charging terminal UU1 S2 of the distribution unit UU1. Similarly, the vehicle V2 is connected to the secondary side vehicle charging terminal UU2 S2 of the distribution unit UU2. The vehicle V1 receives a charging current id1 from the distribution unit UU1. The vehicle V2 receives a charging current id2 from the distribution unit UU2. As used herein, charging is understood as an illustrative term, not a limiting term. Charging can include a flow of power (current) from the distribution units UU1, UU2 towards the vehicles V1, V2 and / or from the vehicles V1, V2 towards the distribution units UU1, UU2. Furthermore, charging can also include supplying power to the vehicles V1, V2 for purposes other than increasing a state of charge (SoC) of a vehicle battery, for example power consumed by on-board equipment. Furthermore, charging can include supplying power to the vehicles V1, V2 which is only indirectly used for increasing the SoC of a battery, for example by intermediation of an on-board (vehicle-bound or vehicle-internal) power distributor.

[0073] According to an embodiment of the present specification, Figure 6 The use case of the example of Fig. 1 is comparable to the use case of the conventional example described above in connection with Fig. 2. In Figure 6In the example of FIG. 1, very short bridges between terminals PT1...PT8 of power unit PU1 and between terminals PT1...PT8 of power unit PU2 are each rated for maximum power, but since they are relatively short, they contribute little to overall system complexity and cost. In one example, the maximum power corresponds to a current of 1000 A. For example, primary side links FSL11, FSL12 are each rated for 1000 A. Secondary side link SSL1 is rated for 250 A, and can help to distribute power sharing between distribution units UU1 and UU2. For example, for an exemplary distance dl = 50 m between power unit PU and each user unit UU1, UU2, 1000 A bus each has a wiring gauge of 240 mm 2 Thus, at least 600 meters of 240 mm 2 gauge wiring is required: 50 m x 3 (per pole) x 2 (for DC+ and DC-) x 2 (outlets). Secondary side link SSL1 requires an additional 250 A wiring, but since distance d2 is much shorter than dl, it contributes little to overall complexity and wiring cost for secondary side link SSL1. Thus, compared to the conventional configuration shown in FIG. 1, Figure 6 The configuration shown in the exemplary embodiment of FIG. 2 can help to save cost and reduce complexity compared to the configuration shown in FIG. 1.

[0074] Figure 7 A variant of the configuration of DC charging system 100 shown in the exemplary embodiment of FIG. 2 is shown. Here only the differences are explained. Figure 5 In addition to the first secondary side link SSL1 of the configuration in FIG. 2, system 100 includes a second secondary side link SSL2, which connects a first secondary side power sharing terminal UU2S6 of second distribution unit UU2 with a second secondary side power sharing terminal UU1S2 of first distribution unit UU1. This allows improved power exchange between distribution units UU1, UU2 (e.g., as needed), while keeping the wiring of primary side links FSL11, FSL12, FSL21, FSL22 at a low complexity level. Figure 5

[0075] A further variant of the configuration of DC charging system 100 shown in the exemplary embodiment of FIG. 2 is shown. Here only the differences are explained. Figure 8 Figure 5 Figure 8 ​​The power units PU in the system 100 comprise 100 kW power modules PM1, PM3, PM5, PM7 and the power units PU comprise 50 kW power modules PM2-1, PM2-2, PM4-1, PM4-2, PM6-1, PM6-2, PM8-1, PM8-2. The power module PM1 is bridged on its secondary side on the power terminal PT1 with the power module PM2-1 on the power terminal PT2-1. The power module PM3 is bridged on its secondary side on the power terminal PT3 with the power module PM4-1 on the power terminal PT4-1. The power module PM5 is bridged on its secondary side on the power terminal PT5 with the power module PM6-1 on the power terminal PT6-1. The power module PM7 is bridged on its secondary side on the power terminal PT7 with the power module PM8-1 on the power terminal PT8-1.

[0076] The user unit UU1 is connected via the primary side link FSL11 to the power modules PM1 and PM2-1. The user unit UU1 is connected via the primary side link FSL12 to the power module PM2-2. The user unit UU2 is connected via the primary side link FSL21 to the power modules PM3 and PM4-1. The user unit UU2 is connected via the primary side link FSL22 to the power module PM4-2. The user unit UU3 is connected via the primary side link FSL31 to the power modules PM5 and PM6-1. The user unit UU3 is connected via the primary side link FSL32 to the power module PM6-2. The user unit UU4 is connected via the primary side link FSL41 to the power modules PM7 and PM8-1. The user unit UU4 is connected via the primary side link FSL42 to the power module PM8-2.

[0077] The user unit UU1 is connected via the secondary side link SSL1 to the user unit UU2. The user unit UU2 is connected via the secondary side link SSL2 to the user unit UU3. The user unit UU3 is connected via the secondary side link SSL3 to the user unit UU4. The user unit UU4 is connected via the secondary side link SSL4 to the user unit UU1.

[0078] As Figure 8 The configuration of the system 100 as shown can help to improve its granularity and / or scalability.

[0079] Figure 9 A configuration of a DC charging system 100 according to an embodiment is shown. For better overview and readability, only some reference signs are repeated for each and every element. In Figure 9In the shown example, the respective secondary DC vehicle connection terminals UU1S2... UU8S2 are implemented as overhead connection lines (OCL). The vehicles VI, V3 can be connected to the secondary DC connection terminals UU1S2... UU8S2, e.g. via a pantograph and the OCL. In the shown example, the vehicle VI is connected to the secondary DC connection terminal UU1S2 and the vehicle V3 is connected to the secondary DC connection terminal UU3S2. Please note that this is a non-limiting example and up to 8 vehicles can be connected. For example, the vehicle VI and the vehicle V3 each use 100 kW to charge their batteries. This example can be seen as an "overnight" configuration, e.g. in a vehicle parking lot, where multiple vehicles charge their batteries at the same time. At least one of the secondary DC vehicle connection terminals UU1S2... UU8S2 (one of the OCLs) can be designated as "fast lane", e.g. for fast charging during the day. As a non-limiting example, during fast charging, the respective vehicle can consume up to four times the overnight charging power, e.g. up to 400 kW at 1000 A. This can be achieved without any 1000 A wiring of the distribution units on the primary side due to the exchange of power via the secondary power sharing links.

[0080] In an example, the respective secondary DC vehicle connection terminals UU1S2... UU8S2 are implemented as overhead connection lines (OCL). The vehicles VI, V3 can be connected to the secondary DC connection terminals UU1S2... UU8S2, e.g. via a pantograph and the OCL. In the shown example, the vehicle VI is connected to the secondary DC connection terminal UU1S2 and the vehicle V3 is connected to the secondary DC connection terminal UU3S2. Please note that this is a non-limiting example and up to 8 vehicles can be connected. For example, the vehicle VI and the vehicle V3 each use 100 kW to charge their batteries. This example can be seen as an "overnight" configuration, e.g. in a vehicle parking lot, where multiple vehicles charge their batteries at the same time. At least one of the secondary DC vehicle connection terminals UU1S2... UU8S2 (one of the OCLs) can be designated as "fast lane", e.g. for fast charging during the day. As a non-limiting example, during fast charging, the respective vehicle can consume up to four times the overnight charging power, e.g. up to 400 kW at 1000 A. This can be achieved without any 1000 A wiring of the distribution units on the primary side due to the exchange of power via the secondary power sharing links. Figure 9 In the shown example, the vehicle VI is connected to the secondary DC connection terminal UU1S2 and the vehicle V3 is connected to the secondary DC connection terminal UU3S2. Please note that this is a non-limiting example and up to 8 vehicles can be connected. For example, the vehicle VI and the vehicle V3 each use 100 kW to charge their batteries. This example can be seen as an "overnight" configuration, e.g. in a vehicle parking lot, where multiple vehicles charge their batteries at the same time. At least one of the secondary DC vehicle connection terminals UU1S2... UU8S2 (one of the OCLs) can be designated as "fast lane", e.g. for fast charging during the day. As a non-limiting example, during fast charging, the respective vehicle can consume up to four times the overnight charging power, e.g. up to 400 kW at 1000 A. This can be achieved without any 1000 A wiring of the distribution units on the primary side due to the exchange of power via the secondary power sharing links.

[0081] Figure 10A configuration of a DC charging system 100 according to an embodiment is shown. For better overview and readability, only some reference numerals are repeated for each and every element. Distribution units UU1...UU4 are connected to power unit PU1 via primary side links FSL11, FSL12... Distribution units UU5...UU8 are connected to power unit PU1 via primary side links FSL51, FSL52... User units UU1...UU8 are interconnected to each other via secondary side links SSL1...SSL7 at their secondary sides. For example, the power modules PM1...PM8 of power unit PU1 and the power modules PM9...PM16 of power unit PU2 each have a power rating of 100 kW. As a non-limiting example, each primary side link is rated at 250 A and each secondary side link is rated at 1500 A.

[0082] A site control unit SCU, in the following simply control unit, is directly or indirectly connected to each of power units PU1, PU2 and distribution units UU1...UU8 via data lines DL. Each distribution unit UU1...UU8 comprises a switch assembly S1...S8 acting as a current distributor.

[0083] The control unit SCU is configured to determine short circuit safe positions of the switch assemblies and to control each switch assembly to be in only one of the determined short circuit safe positions.

[0084] Furthermore, the control unit SCU determines a requested value of a vehicle charging current requested at any one of the secondary side DC vehicle connection terminals of any one of the distribution units UU1...UU8. As a non-limiting example, assume that the first distribution unit UU1 is requested for outputting a vehicle charging current at a requested value. The control unit SCU determines the current carrying capacity of the one or more primary side links of the first distribution unit UU1. The control unit SCU determines the current carrying capacity of the secondary side DC link between the first distribution unit UU1 and the second distribution unit UU2. The control unit SCU controls each current distributor (switch assembly) S1...S8 such that the sum of the current carrying capacities matches or exceeds the requested value.

[0085] This approach can be extended by the control unit to the remaining distribution units and their respective primary and secondary side links. For example, the control unit SCU can adapt the available current at each secondary side DC vehicle connection terminal (and thereby the power available at that terminal) as needed by controlling the current distributors S1...S8 accordingly.

[0086] For example, in the above example, when the request value is 100 kW, the control unit SCU can control the current distributors in each distribution unit such that power is available at each secondary DC vehicle connection terminal. Further, when the request value is for example 200 kW, the control unit SCU can control the current distributors in each distribution unit such that the requested power of 200 kW is available at the corresponding secondary DC vehicle connection terminal, control the other terminal in the corresponding secondary DC vehicle connection terminal to be unavailable (off), and control the remaining terminals to be available at 100 kW. In the illustrated example, this can be extended up to 500 kW at one secondary DC vehicle connection terminal, while all remaining terminals are controlled to be unavailable (off). Thereby, a granularity (in a non-limiting example, 100 kW granularity) can be achieved between the secondary DC vehicle connection terminals, while in an extreme case, the maximum power (in a non-limiting example, 500 kW) is possible at one secondary DC vehicle connection terminal.

[0087] It should be noted that the embodiments described herein can be freely combined and / or certain features can be omitted as appropriate. For example, the grouping / jumpering of power modules at the power terminals can be performed arbitrarily depending on the site configuration and / or use case. Non-limiting examples include two per group, four per group, or any other grouping. As a further example, the cascading of distribution units (jumpering / bridging at the secondary power sharing terminals) can be performed arbitrarily depending on the site configuration and / or use case. This allows for a high degree of modularity at the interconnection point and a high degree of configurability by appropriately applying / altering the jumpering / bridging.

[0088] With the configuration described herein, power can be flexibly exchanged between distribution units. For example, a distribution unit can be connected to a power unit via a primary link having a certain current carrying capacity, and the rated power that can be delivered by the power unit via this primary link is specified by this current carrying capacity (and link voltage). With the techniques described herein, this installed power of the distribution unit can be exceeded by "borrowing" power from neighboring distribution unit(s) via the secondary link(s), while the cost resulting from the wiring specifications of the primary link(s) can be kept low.

[0089] While specific embodiments have been shown and described, it will be understood that this does not limit the claimed invention to the preferred embodiments, and that skilled persons will appreciate that various changes and modifications can be made without departing from the spirit and scope of the claimed invention. The specification and drawings should therefore be regarded in an illustrative rather than restrictive sense. The claimed invention is intended to embrace alternative, modifications and equivalents.

Claims

1. A DC charging distribution unit, comprising: a first primary side terminal for receiving a first input current from a power unit; a secondary side DC vehicle connection terminal connectable to a vehicle to provide a vehicle charging current; a first secondary side power sharing terminal connectable to another DC charging distribution unit; and a current distributor operable to select between: - a vehicle charging configuration, wherein the first input current is used to feed the vehicle charging current to the secondary side DC vehicle connection terminal; and - a power sharing configuration, wherein the first input current is used to feed a sharing current to the first secondary side power sharing terminal.

2. The distribution unit according to claim 1, further comprising a second secondary side power sharing terminal connected to the first primary side terminal and connectable to yet another DC charging distribution unit for obtaining input power from the second secondary side power sharing terminal. The current distributor is further operable to select between:

3. The dispensing unit of claim 1, further comprising a second primary side terminal for receiving a second input current from a power unit, wherein, - a combined input configuration, wherein the first primary side terminal and the second primary side terminal are combined; and - a separate input configuration, wherein the first primary side terminal and the second primary side terminal are disconnected from each other.

4. The distribution unit according to claim 1, further comprising a power converter configured to convert the first input current and / or the second input current into the vehicle charging current and / or the sharing current. The current distributor is a switch assembly, wherein the first input current and / or the second input current are each a DC current, wherein the vehicle charging configuration is a vehicle charging switch configuration, wherein the first primary side terminal is connected to the secondary side DC vehicle connection terminal, wherein the power sharing configuration is a power sharing switch configuration, wherein the first primary side terminal is connected to the first secondary side power sharing terminal.

5. The dispensing unit of claim 1, wherein, 6. A DC charging distribution unit, comprising: a first primary side terminal for receiving a first input current from a power unit; a secondary side DC vehicle connection terminal connectable to a vehicle to provide a vehicle charging current; a first secondary side power sharing terminal connectable to another DC charging distribution unit; a second primary side terminal for receiving a second input current from a power unit, wherein the current distributor is operable to select between: - a vehicle charging configuration, wherein the first input current is used to feed the vehicle charging current to the secondary side DC vehicle connection terminal; - a power sharing configuration, wherein the first input current is used to feed the sharing current to the first secondary side power sharing terminal; - a combined input configuration, wherein the first primary side terminal and the second primary side terminal are combined; and - a separate input configuration, wherein the first primary side terminal and the second primary side terminal are disconnected from each other. The separate input configuration comprises 7. The dispensing unit of claim 6, wherein, - a vehicle charging configuration, wherein the first primary side terminal but not the second primary side terminal is connected to the secondary side DC vehicle connection terminal; and - a separate power sharing configuration, wherein the second primary side terminal but not the first primary side terminal is connected to the first secondary side power sharing terminal. ​ 8. A DC charging system comprising at least one power unit and at least a first and a second distribution unit, wherein the first and the second distribution unit each comprising: a first primary side terminal for receiving a first input current from a power unit; a secondary side DC vehicle connection terminal connectable to a vehicle to provide a vehicle charging current; a first secondary side power sharing terminal connectable to another DC charging distribution unit; and a current distributor operable to select between: - a vehicle charging configuration, wherein the first input current is used to feed the vehicle charging current to the secondary side DC vehicle connection terminal; and - a power sharing configuration, wherein the first input current is used to feed the shared current to the first secondary side power sharing terminal, wherein each power unit comprises at least one power terminal, wherein the distribution units are each spaced apart from the power units by at least a first distance, and wherein adjacent ones of the distribution units are spaced apart from each other by at most a second distance; wherein adjacent ones of the distribution units are connected to each other at their secondary side power sharing terminals via a first secondary side link; wherein at least one of the primary side terminals of the first and the second distribution unit is electrically connected to the power terminal of the at least one power unit via a primary side link.

9. The DC charging system of claim 8, wherein, a maximum vehicle charging current at the secondary side DC vehicle connection terminal of the first distribution unit is less than or equal to a sum of a current carrying capacity of the primary side link of the first user unit and a current carrying capacity of the secondary side link between the first and the second user unit.

10. The DC charging system of claim 8, further comprising a third distribution unit, wherein the third distribution unit comprising: a first primary side terminal for receiving a first input current from a power unit; a secondary side DC vehicle connection terminal connectable to a vehicle to provide a vehicle charging current; a first secondary side power sharing terminal connectable to another DC charging distribution unit; and a current distributor operable to select between: - a vehicle charging configuration, wherein the first input current is used to feed the vehicle charging current to the secondary side DC vehicle connection terminal; and - a power sharing configuration, wherein the first input current is used to feed the shared current to the first secondary side power sharing terminal, wherein the distribution units are connected to each other at their secondary side power sharing terminals via respective secondary side links; wherein a maximum vehicle charging current at the secondary side DC vehicle connection terminal of the first distribution unit is less than or equal to a sum of current carrying capacities of the primary side links of the first distribution unit to the third distribution unit; and wherein current carrying capacities of the secondary side links between the first and the second distribution unit and between the second and the third distribution unit are designed to be at least the sum.

11. The DC charging system of claim 8, wherein, the first secondary side power sharing terminals of each distribution unit and its respective adjacent distribution units are connected to each other via respective secondary side links.

12. The DC charging system of claim 8, wherein, The first secondary side power sharing terminal of each distribution unit is connected to the second secondary side power sharing terminal of its respective adjacent distribution unit.

13. The DC charging system of claim 8, wherein, Each power terminal is a DC power terminal.

14. The DC charging system of claim 8, wherein, The first distance is 10 m or more, optionally 20 m or more, or 50 m or more; and / or The second distance is shorter than the first distance, optionally at most 30%, 20%, or 10% of the first distance.

15. The DC charging system of claim 8, further comprising a control unit configured to: determine a requested value of the vehicle charging current; determine a current-carrying capacity of the primary side link of the first distribution unit; determine a current-carrying capacity of the secondary side link between the first distribution unit and the second distribution unit; control each of the current distributors such that the sum of the current-carrying capacities matches or exceeds the requested value.

16. The DC charging system of claim 15, wherein, The current distributors are each a switch assembly, and wherein the control unit is further configured to determine one or more short-circuit safe positions for each of the switch assemblies, and to control each of the switch assemblies to be in only any one of the determined short-circuit safe positions.

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