On-board charger configuration system

Abstract

A configuration system 202 for an on-board charging circuit (OBC) for a vehicle comprises: plural input nodes 304-310 coupled to a split-phase or three-phase power system; plural output nodes 402-412 coupled to a power converter of an OBC; and plural switches 502-508 coupled between the input and output nodes. The system determines whether a split-phase or three-phase power system is to be coupled to the input nodes. For a split-phase power system, a switch configuration is modified to couple at least one redundant input node with at least one output node. Specifically, first switch 502 is closed between the first and third input nodes 304,308; second switch 504 is closed between the second and fourth input nodes 306,310; third switch system 506 is closed between the first input node 304 and the third output node 406; and fourth switch system 508 is closed between the first input node 304 and fifth output node 412. The first and third input nodes 304,308 couple to the first, third and fifth output nodes 402,406,410. The second and fourth input nodes 306,310 couple to the second, fourth and sixth output nodes 404,408,412. The switch configuration may be modified for use with a single-phase system.

Description

TECHNICAL FIELD The present disclosure relates to an on-board charger configuration system. Aspects of the invention relate to a configuration system for an on-board charging circuit of a vehicle, to an on-board charger system for a vehicle, to a vehicle comprising the on-board charger system or the configuration system and to a method of configuring power source connections to an on-board charging circuit of a vehicle. BACKGROUND It is known to provide battery-electric vehicles (BEV) or plug-in hybrid electric vehicles (PHEV) with the means to be charged by both DC and AC power. Vehicles may include an on-board charger (OBC) which is configured to receive an AC power input, convert this to DC and charge the vehicle batteries. The OBC may be configured to receive a three-phase or singlephase power system input. Three-phase power systems can supply greater power compared to single-phase power systems, allowing a faster charging rate. Some countries, such as the US, provide split-phase power system connections in homes. Split-phase power systems can allow faster charging than single-phase power systems. As available power system types vary within and especially between countries, vehicles may require different on-board chargers for different marketplaces. As such, the design, manufacture and installation of a plurality of different on-board chargers is required. This increases complexity of manufacturing, requiring multiple production lines or reducing the efficiency of a single production line. It is an aim of the present invention to address one or more of the disadvantages associated with the prior art, allowing the manufacture of a single on-board charger system which is compatible with single-phase, three-phase and split-phase power systems. It would also be beneficial to provide an efficient design. SUMMARY OF THE INVENTION Aspects and embodiments of the invention provide a configuration system for an on-board charging circuit of a vehicle, to an on-board charger system for a vehicle, to a vehicle comprising the on-board charger system or the configuration system and to a method of configuring power source connections to an on-board charging circuit of a vehicle. According to an aspect of the present invention there is provided a configuration system for an on-board charging circuit of a vehicle, the configuration system comprising: a plurality of input nodes for coupling to a split-phase power system or a three-phase power system; a plurality of output nodes for coupling to a power converter of an on-board charging circuit; a plurality of switches coupled between the plurality of input nodes and the plurality of output nodes, wherein the configuration system is configured to: modify a configuration of the switches, wherein if the plurality of input nodes are to be coupled to a split-phase power system, the configuration of the switches is modified such that the switching circuit couples at least one redundant input node of the plurality of input nodes with at least one output node of the plurality of output nodes. According to an aspect of the present invention there is provided configuration system for an on-board charging circuit of a vehicle, the configuration system comprising: a plurality of input nodes for coupling to a split-phase power system or a three-phase power system; a plurality of output nodes for coupling to a power converter of an on-board charging circuit; a plurality of switches coupled between the plurality of input nodes and the plurality of output nodes, wherein the configuration system is configured to: determine whether a power system to be coupled to the plurality of input nodes is a split-phase power system or a three-phase power system; modify a configuration of the switches, wherein if the plurality of input nodes are to be coupled to a split-phase power system, the configuration of the switches is modified such that the switching circuit couples at least one redundant input node of the plurality of input nodes with at least one output node of the plurality of output nodes. A redundant input node is an input node which is not typically connected to a particular power system. For example, a splitphase power system typically uses two conductors to provide a power source connection, whereas a three-phase power system uses four conductors thereby providing two redundant input nodes when a split-phase connection is made. By using at least one redundant input node in addition to a typical connection node, the current provided to the on-board charging configuration system by the split-phase system may be routed through multiple input nodes and conductive traces of the charging circuit configuration system. This reduces the current in each input node and trace, allowing smaller conductive input nodes and traces than would otherwise be needed, and allowing any additional components, such as common-mode chokes, to be specified for use at a lower power level. A configuration system which is suitable for coupling to both a split-phase power system and a three-phase power system may include four input nodes. This allows the three-phases and neutral connections from the three-phase power system to be coupled through the configuration system to the on-board charging circuitry. A split-phase system may include a first-phase and a second-phase connection. These may be coupled to two of the four input nodes, typically leaving two input nodes redundant. A redundant input node is an input node which does not have to be used to allow connection of the power system and the charging circuit configuration system. Determining whether the system coupled to the plurality of input nodes is a split-phase power system or three-phase power system may comprise receiving a signal from an external source identifying the power system. The external source may be an external charging system. Alternatively, the configuration system may be pre-configured during manufacture of a vehicle so that the vehicle may suit a particular market having a predominantly three-phase power system for charging electric vehicles, or a predominantly split-phase power system for charging electric vehicles. The plurality of input nodes may comprise a first input node, a second input node, a third input node and a fourth input node; and wherein modifying the configuration of the switches when the plurality of input nodes are to be coupled to a split-phase power system comprises coupling a first phase connection of the split-phase power system to the output nodes using the first input node and the third input node and a second phase connection of the split-phase power system to the output nodes using the second input node and the fourth input node. By having four input nodes, the configuration system may receive a three-phase power system connection. Where a splitphase power system is coupled or is expected to be coupled to an inlet of a vehicle, and hence to the on-board charging circuit via the configuration system, two of the four input nodes are redundant nodes and are reused as mentioned above. By coupling each phase of the split-phase power system using two input nodes, the current at each respective input node and respective sections of the charging circuit configuration circuit are reduced. The plurality of output nodes may comprise a first output node, a second output node, a third output node, a fourth output node, a fifth output node and a sixth output node for coupling to a three-phase stack AC-DC converter. Providing six output nodes allows simple-coupling to a three-phase stack AC-DC converter. The stack AC-DC converter may comprise three independent systems, with each system capable of converting a single-phase of the three-phase system. Where the charging circuit configuration system is coupled to a single or split-phase system, the charging circuit configuration system may be configured to utilize all of the independent systems for the conversion, by coupling the input nodes and output nodes using the switches. According to another aspect of the invention, there is provided a first switch coupled between the first input node and the third input node; a second switch coupled between the second input node and the fourth input node; a third switch system to couple either the first input node or the third input node to the third output node; a fourth switch system to couple either the first input node or the fourth input node to the fifth output node. This switch configuration may be used to configurably route input current from a single-phase, split-phase or three-phase system, to output nodes of the configuration system. The switches allowing current reduction in individual conductive paths of the configuration system by splitting and recombining currents at internal nodes of the configuration system. This allows the higher-power / higher-current split-phase power system to be used without substantial changes to the current carrying ability of traces or paths within the configuration circuit. A switch system may comprise a single switch or multiple switches. For example, the third and fourth switch systems may comprise, respectively, one single-pole double throw switch or two single-pole single-throw switches. Any switch arrangement may be provided in the switch system which is capable of selectively coupling the respective nodes. According to another aspect of the invention, when the input nodes are configured to be coupled to a split-phase power system: the first switch is closed; the second switch is closed; the third switch system is closed between the first input node and the third output node; the fourth switch system is closed between the first input node and the fifth output node. Coupling the switches in this particular fashion reduces current in certain areas of the charging circuit configuration system. According to another aspect of the invention, when the input nodes are configured to be coupled to a three-phase system: the first switch is open; the second switch is open; the third switch system is closed between the third input node and the third output node; the fourth switch system is closed between the fourth input node and the fifth output node. According to another aspect of the invention, when the input nodes are configured to be coupled to a single-phase system: the second switch is open; the third switch system is closed between the first input node and the third output node; the fourth switch system is closed between the first input node and the fifth output node. According to another aspect of the invention, the first input node is coupled to the first output node. According to another aspect of the invention, the second input node is coupled to the second, fourth and sixth output nodes. According to an aspect of the invention, an on-board charger system for a vehicle is provided, the on-board charger comprising: the configuration system; and a three-phase stack AC-DC converter coupled to the plurality of output nodes of the charging configuration circuit. According to another aspect, the configuration system is configured to provide an equal current to respective stacks of the three-phase stack AC-DC converter (400) when the plurality of input nodes (304-310) are coupled to a split-phase power system or a three-phase power system. Providing an equal current to each of the phases of the totem-pole allows the totempole converter to operate with greater efficiency. According to an aspect of the invention, the first and second output nodes are coupled to a first stack of the stack AC-DC converter; the third and fourth output nodes are coupled to a second stack of the stack AC-DC converter; and the fifth and sixth output nodes are coupled to a third stack of the stack AC-DC converter. According to an aspect of the invention, there is provided a vehicle comprising either: the configuration system; or the onboard charger system. The vehicle may further comprise a charging inlet; a wiring loom coupled between the charging inlet and the configuration system, the wiring loom comprising: a conductive link coupling the first input node and the third input node; and a conductive link coupling the second input node and the fourth input node. Providing conductive links between the input nodes in this manner is one way to achieve a split-phase system being coupled to all four input nodes in use on a vehicle. According to an aspect of the invention there is provided a method of configuring power source connections to an on-board charging circuit of a vehicle, the method comprising: determining whether a power system to be coupled to a plurality of input nodes of a configuration system is a split-phase power system or a three-phase power system; modifying a configuration of a plurality of switches of the configuration system, wherein if the plurality of input nodes are to be coupled to the split-phase power system, the configuration of the switches is modified such that the switching circuit couples at least one redundant input node of the plurality of input nodes with at least one output node of the plurality of output nodes. Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and / or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and / or features of any embodiment can be combined in any way and / or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and / or incorporate any feature of any other claim although not originally claimed in that manner. BRIEF DESCRIPTION OF THE DRAWINGS One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is an illustration of a vehicle; Figure 2 is a block diagram of a system including an on-board charger system; Figure 3a is a block diagram of a configuration system; Figure 3b is a block diagram of a configuration system and a control system; Figure 4 is a schematic diagram of a stack power converter; Figure 5a is a schematic diagram of a configuration system including switch systems; Figure 5b is a schematic diagram of a configuration system including switch systems and phase relays; Figures 6 to 8 are schematic diagrams of the configuration system including switch systems positioned for a splitphase, a three-phase and a single phase power system, respectively; and Figure 9 is a flow chart showing a method of controlling the configuration system. DETAILED DESCRIPTION A vehicle 100 in accordance with an embodiment of the present invention is described herein with reference to the accompanying Figure 1. As shown in Figure 1, the vehicle 100 comprises an on-board charger system 102. The on-board charger system 102 is suitable for coupling to a power system 104 using a charging cable 106. The power system 104 may be or form part of an electric vehicle supply equipment (EVSE) configured to supply AC power to the vehicle 100 from an electricity grid. The EVSE may be configured to provide one or more of single-phase, three-phase or split-phase connections to the vehicle 100. The power system 104 may alternatively be a direct connection to the electricity grid not via an EVSE, providing one of single-phase, three-phase or split-phase connections to the vehicle 100. The on-board charger 102 is configured to receive a current from the power system 104 using the charging cable 106. The on-board charger 102 converts the supplied AC grid current to a DC current, which may then be used by a battery management system 108 to charge a battery 110 of the vehicle 100. Where the power system 104 is an EVSE or equivalent, the power system 104 and the on-board charger 102 are capable of communicating using a communications link as is known in the art, and which is enabled by one or more of several EV charging standards governing how the EVSE and vehicle 100 communicate. Appropriate communications connections are typically included in the charging cable 106. The power system 104 may also communicate with other systems in the vehicle, such as microcontroller units or control systems. This allows both the on-board charger 102 and the power system 104 to configure themselves or to be configured by other processors or microcontrollers of the vehicle 100. This may include setting the current or voltage level supplied by the power system 104 to the on-board charger 102 and exchanging information on maximum charging rates and power system type. The power system 104 is coupled to the on-board charger 102 using an inlet 114 of the vehicle 100. The charging cable 106 is terminated by a connector 112, with the connector 112 being couplable to the inlet 114. The inlet 114 and connector 112 may comply with one of several vehicle charging standards, such as IEC 62196 and SAE J3068. Inlet 114 and connector 112 therefore may be one of a number of different types of AC charging connector, such as a IEC 62196 type-2 connector, a Combined Charging System (CCS) connector or a J3068 connector. Type-2 and similar connectors allow both power and data to be transmitted. Different inlets and connectors may be used in different regions. For example, in Europe, a CCS connector may be used, with the CCS connector having a neutral pin, a first live pin, a second live pin and a third live pin. The CCS connection comprises further pins for DC charging and to transmit data. In North America, a NACS connector may be used, with the NACS connector having a first live pin, a second live pin and further pins to transmit data. The NACS system is currently being standardised as SAE J3400. The connectors may also include ground pins. In some locations, the power system 104 may be or provides a single-phase connection to an electricity grid. A single-phase connection comprises a single live and a single neutral connection between the power system 104 and the on-board charger 102. In some locations, the power system 104 may be or provide a three-phase connection to an electricity grid. The three-phase connection comprises three live connections and a single neutral connection between the power system 104 and the on-board charger 102. In some locations, the power system 104 may be or provides a split-phase power system. A split-phase power connection is a type of single-phase system where there are two live connections between the power system 104 and the on-board charger 102. The two live connections carry currents which are 180° out of phase with each other and typically have a voltage of 240V there between. A split-phase system Is capable of providing greater power when compared to a standard single-phase system. The different types of power systems may be particularly common in different locations. For example, single-phase and three-phase power systems are particularly common in Europe, whereas split-phase systems are particularly common in the US. For this reason, different inlet 114 and connector 112 types are used in the different locations. As such, a battery electric vehicle or plug-in hybrid electric vehicle 100 may have three possible input power system connections (single-phase, split-phase, three-phase). As not every charging location may provide all three power system connections, it is desirable to provide an on-board charger which is capable of connecting to all three power system connections. Providing an on-board charger which is capable of operating with all three of the above outlined power-system connections enables a single on-board charger to be manufactured, with the single on-board charger capable of being used in a large variety of locations. This reduces manufacturing complexity. Figure 2 is block diagram of a system 200 including the power system 104 and on-board charger 102. The on-board charger 102 comprises a configuration system 202 and a power converter 204. The configuration system 202 is coupled to the power system 104. Whilst the configuration system 202 and the power converter 204 are shown as separate elements or systems that are connected within the on-board charger 102, the configuration system and the power converter may be co-packaged, for example implemented on the same circuit-board, substrate or within the same circuit system. The configuration system 202 and the power converter 204 may be manufactured together as a single unit or system, or manufactured separately and coupled within the on-board charger system 102. Figure 3a is a block diagram of the configuration system 202 of the system 200 of Figure 2. The configuration system 202 includes an input connector 302 comprising four input nodes 304-310. This allows a three-phase system comprising three live connections or conductors and a single neutral connection or conductor to be coupled to the configuration system 202. Split phase and single-phase systems both require two connections or conductors and can therefore also be coupled to the input nodes 304-310. The input nodes 304-310 of the input connector 302 may be coupled to the different live and neutral pins included in the connector 112 coupled to the inlet 114 of the vehicle. The configuration system also includes four output nodes 312-318. The output nodes 312-318 are suitable for coupling to a power-converter 204. Whilst four output nodes 312-318 are shown, the number of output nodes is dependent on the power converter 204 type that is coupled to the plurality of output nodes 312-318. As such, there may be two, three, four, five, six, seven or eight output nodes. A plurality of switches 320 are coupled between the input nodes 304-310 and the output nodes 312-318. The input nodes 304-310 are coupled to the plurality of switches using conductive traces, such as printed circuit board, PCB, traces. Similarly, the plurality of switches 320 and plurality of output nodes 312-318 are coupled to one another using conductive traces. A split-phase power system requires two live connections or conductors. As such, the split-phase system may be coupled to two of the four input nodes 304-310. The remaining two input nodes may be considered redundant. The plurality of switches 320 may be configured based on the knowledge that the input is a split-phase system and couple the two utilised input nodes of the plurality of input nodes 304-310 to the output nodes 312-318. Where the power system 104 is a single-phase power system, the single-phase system may be coupled to two of the four input nodes 304-310. The remaining two input nodes may be considered redundant. The plurality of switches 320 may be configured based on the knowledge that the input is a single-phase system and couple the two utilised input nodes of the plurality of input nodes 304-310 to the output nodes 312-318. Where the power system 104 coupled to the input nodes 304-310 is a three-phase power system, all four of the plurality of input nodes 304-310 may be utilized, with the three-phase system coupled to all four input nodes 304-310. The plurality of switches 320 may be configured based on the knowledge that the input is a three-phase system and couple the four utilised input nodes of the plurality of input nodes 304-310 to the output nodes 312-318. As such, the four input nodes 304-310 are suitable for coupling to any of a single-phase, split-phase or three-phase power system. Split-phase systems may be relatively high current systems compared to single-phase systems and three-phase systems. For example, for on-board charging of a vehicle in the US, a split-phase power system may be rated to 19.2kW at 80A RMS. In contrast, a single-phase power system may be rated to 7kW at 32A RMS and a three-phase power system may be rated to 22kW at 32A RMS per phase. Split-phase systems clearly offer higher power charging when compared to single-phase systems, however the current demands are much greater. The configuration system 202 can be designed such that it is capable of receiving the highest possible input current that can be supplied by any of the single-phase, three-phase or split-phase systems. As such, typically the components of the system, such as common mode chokes and phase relays can be designed to carry 80A RMS which is supplied by a split-phase system. Further, the conductive traces would be designed to carry 80A RMS. However, this requires more expensive and larger components, and greater copper usage in the conductive traces. To overcome this issue, the configuration system 202 and in particular the plurality of switches 320 may be configured to utilize at least one redundant input node when a split-phase power system is connected to the input nodes 304-310. Where the input nodes 304-310 are coupled to a split-phase power system, the configuration of the switches 320 is modified such that the plurality of switches 320 couple at least one redundant input node of the input nodes 304-310 with at least one output node of the plurality of output nodes 312-318. This allows the split-phase power system to be coupled to more than two input nodes, for example to four input nodes as shown in the illustrated embodiment. For example, each phase of the split-phase power system may be coupled to two input nodes of the four input nodes 304-310, utilising the two redundant input notes. By configuring the plurality of switches 320 to allow this, a current in each of the conductive paths 322-328 may be reduced by half. This reduces the current carrying requirements on the configuration circuit 202. For example, where a split-phase system is coupled to two input nodes, such as input nodes 304 and 306, each of the conductive traces 322 and 324 would need to be rated to carry a current of 80A. In contrast, if the split-phase system is coupled to redundant nodes as well, such that a first phase of the split-phase system is coupled to input nodes 304 and 308 and a second phase of the split phase system is coupled to input nodes 306 and 310, the current rating for each of the conductive traces 322-328 is reduced to 40A. External connections, coupling the two input nodes to a single phase of the split-phase power system, may be provided by the power system 104, or a conductive link in the wiring harness of the vehicle 100. Similarly, any further components in the path of these conductive traces 322-328, such as common mode chokes, may also have a lower current rating. As such, modifying the configuration of the switches 320 when the plurality of input nodes are to be coupled to a split-phase power system may comprise coupling a first phase connection of the split-phase power system to the output nodes using the first input node 304 and the third input node 308 and a second phase connection of the split-phase power system to the output nodes using the second input node 306 and the fourth input node 310. Overall, configuring the plurality of switches in this manner reduces the current in each input node and trace, allowing smaller conductive traces than would otherwise be needed, and allowing any additional components, such as common-mode chokes, to be specified for use at a lower power level. Whilst current levels of 80A RMS and 40A RMS are discussed here, the split-phase power system may provide different current levels. Figure 3b is a block diagram of the configuration system 202 and a control system 330. As well as the power-input connectors, the connector 112 and inlet 114 may further include one or more data pins. Both CCS and NACs connectors include two data pins, also referred to as the CP and PP pins. As such, data may be provided to the vehicle 100 at data input node 332. Data input node 223 may comprise two data input nodes coupled to the CP and PP pins of the charging connectors. The data input node 332 may receive information from the power system 104 as to the type of power system coupled to the input nodes 304-310, allowing the configuration system 202 to be configured in dependence on the type of power system coupled to the input nodes 304-310. The vehicle 100 may include a control system 330. The control system 330 may form part of a microcontroller, microcontroller unit MCU, or system of microcontrollers configured to operate the vehicle 100. For example, the control system 330 may form part of the central processing circuitry of the vehicle 100 which controls a number of different vehicle 100 functions. The control system 330 may alternatively be a part of the on-board charger 102. The control system 330 may receive information from the power system 104 using charging cable 106. Determining whether the power system 104 coupled to the plurality of input nodes is a split-phase power system, a singlephase power system or a three-phase power system may comprise receiving a signal from the power system 104 using communications link 112 which identifies the power system type. Alternatively, determining the power system type may comprise sensing the power supplied to the input nodes 304-310. This may involve coupling sensing terminals to each of the input nodes 304-310, or sensing the currents received at the power converter 204. The control system 330 may configure the plurality of switches 320 in dependence on the power system type. The control system 330 as illustrated in Figure 3b comprises one controller 334, although it will be appreciated that this is merely illustrative and instead multiple controllers may be used. The controller 334 comprises processing means 336 and memory means 338. The processing means 336 may be one or more electronic processing device 336 which operably executes computer-readable instructions. The memory means 338 may be one or more memory device 338. The memory means 338 is electrically coupled to the processing means 336. The memory means 338 is configured to store instructions, and the processing means 336 is configured to access the memory means 338 and execute the instructions stored thereon. The controller 334 comprises an input means 340 and an output means 342. The input means 340 may comprise an electrical input 340 of the controller 334. The output means 342 may comprise an electrical output 342 of the controller 334. The input 340 is arranged to receive a power system type signal 344 from the power system 104. The power system type signal 344 is an electrical signal which is indicative of a power system type (e.g. whether the power system is single-phase, split-phase or three-phase). The power system type signal 334 may be provided by the power system 104. Alternatively, the power system type signal may be determined based on the voltages sensed at the input nodes 304-310. The output 342 is arranged to output a switch control signal 346 which is indicative of a switch configuration for controlling the plurality of switches. The control system 330 is an optional component, and instead the plurality of switches may be configured by a different control system or processer. Alternatively, the configuration system 202 may be pre-configured during manufacture of a vehicle 100 so that the vehicle 100 may suit a particular market having a predominantly three-phase power system for charging vehicles, or a predominantly split-phase power system for charging vehicles. For example, the configuration system 202 may be configured or pre-configured based on the assumption that a split-phase system will be coupled to the plurality of input nodes 304-310. The power converter 204 which forms part of the on-board charger system 102 is an AC-DC converter coupled to the output nodes 312-318 of the configuration system 202. The power converter 204 receives the AC current provided by the power system 104 and controlled by the configuration system 202 and converts this to a DC current. The DC current may then be used by a number of systems within the vehicle 100, such as by the battery management system 108 to charge the vehicle’s 100 battery 110. The power converter 204 may be one of a number of different known AC-DC conversion topologies, such as a single stage topology. The single-stage topology may be a stack-based converter including a plurality of stacks. Alternatively a multi-leg power-based design such as a traditional three-phase totem-pole converter with power factor correction may be used. Each converter type may have a different number of inputs and require the configuration system 202 to modify the connections of the plurality of switches in different ways to render it compatible with single-phase, split-phase and three-phase systems, whilst reducing the current in each trace or conductor when the system is operating with a split-phase power system 104 input. Figure 4 is a schematic diagram of a three-phase stack-based power converter 400. The three-phase stack-based power converter 400 includes six input nodes 414-424 which are coupled to corresponding output nodes 402-412 of the configuration system 202. The first output node 402 and second output node 404 of the configuration system 202 are coupled to the first stack 426 of the stack-based converter 400 using input nodes 414 and 416. The third output node 406 and fourth output node 408 of the configuration system 202 are coupled to the second stack 428 of the stack-based converter 400 using input nodes 418 and 420. The fifth output node 410 and sixth output node 412 of the configuration system 202 are coupled to the third stack 430 of the stack-based converter 400 using input nodes 422 and 424. Whilst the configuration system 202 and stackbased power converter 400 are described as having output nodes 402-412 and input nodes 414-424 respectively, the configuration system 202 and stack-based power converter 400 may be directly coupled, such that no terminal is present between the systems. Each of the three stacks 426-430 may be considered to act as an independent single-phase power converter. Each stack 426-430 receives a live connection and a neutral connection and operates to convert the AC signals to DC signals. When the stack-based power converter 400 is coupled to a three-phase power system, each stack 426-430 is coupled to a respective one of the three live connections / phases and to the neutral connection / phase. When the stack-based converter 400 is coupled to a single-phase or split-phase power system, it is possible to use only a single one of the three stacks 426-430. For example, for a single-phase system, a live connection may be coupled to node 414 and a neutral connector coupled to node 416. For a split-phase system, a first live connection may be coupled to node 414 and a second live connection may be coupled to node 416. By connecting the power system to the stack-based converter 400 in this way, only the first stack 426 is used to convert the AC input to a DC output. Figure 5a is a schematic diagram of configuration system 202 which may be used when the power converter 204 is a stackbased AC-DC power converter 400. The configuration system 202 comprises six output nodes corresponding to those shown in Figure 4: a first output node 402, a second output node 404, a third output node 406, a fourth output node 408, a fifth output node 410 and a sixth output node 412 for coupling to the stack-based AC-DC converter 400 which is also shown in Figure 4. The configuration system includes four switch systems: a first switch system 502, a second switch system 504, a third switch system 506 and a fourth switch system 508. The switch systems are coupled between the input nodes 304-310 of the configuration system 202 and the output nodes 402-412 of the configuration system 202. In this way, the plurality of switch systems 502-508 couple the power system 104 from the outside of the vehicle 100 to the power converter 204 of the on-board charger system 102. The input nodes 304-310 may be considered in terms of how they couple or would be coupled to a standard electric vehicle supply equipment or a standard three-phase charging connector, such as a type-2 CCS connector. A type-2 connector may supply three line or live connections and one neutral connection. With reference to these, the first input node 304 is a first line input node 304. The second input node 306 is a neutral input node 306. The third input node 308 is a second line input node 308. The fourth input node 310 is a third line input node 310. These input nodes may be coupled to the respective pins or lines of the electric vehicle supply equipment or of the connector 112 using a portion of a wiring harness. When the system is coupled to a three-phase system, the first line of the power system 104 is coupled to the first line input node 304, the neutral line of the power system 104 is coupled to the neutral input node 306, the second line of the power system 104 is coupled to the second line input node 308 and the third line of the power system 104 is coupled to the third line input node 310. The first switch system 502 is coupled between the first input node 304 and the third input node 308. The first switch system 502 is configured to couple or decouple the first input node 304 and third input node 308. The first switch system 502 comprises a single-pole single-throw switch. When the single-pole single-throw switch is open, the first 304 and third 308 input nodes are disconnected. When the single-pole single-throw switch is closed, the first 304 and third 308 input nodes are connected. The second switch system 504 is coupled between the second input node 306 and the fourth input node 310. The second switch system 504 is configured to couple or decouple the second input node 306 and fourth input node 310. The second switch system 504 comprises a single-pole single-throw switch. When the single-pole single-throw switch is open, the second 306 and fourth 310 input nodes are disconnected. When the single-pole single-throw switch is closed, the second 306 and fourth 310 input nodes are connected. The third switch system 506 is coupled between the first input node 304, the third input node 308 and the third output node 406. The third switch system 506 is configured to couple or decouple the first input node 304 and third output node 406 and to couple or decouple the third input node 308 and the third output node 406. The third switch system 506 comprises a singlepole double-throw switch which may be connected in one of two positions. The pole of the single-pole double-throw switch is coupled to the third output node 406, with the throw configurable to couple either the first input node 304 or the third input node 308 to the third output node 406. When the single-pole double-throw switch is connected in a first position, the first input node 304 and the third output node 406 are connected. When the single-pole double-throw switch is connected in a second position, the third input node 308 and the third output node 406 are connected. The fourth switch system 508 is coupled between the first input node 304, the fourth input node 310 and the fifth output node 410. The fourth switch system 508 is configured to couple or decouple the first input node 304 and fifth output node 410 and to couple or decouple the fourth input node 310 and the fifth output node 410. The fourth switch system 508 comprises a single-pole double-throw switch which may be connected in one of two positions. The pole of the single-pole double-throw switch is coupled to the fifth output node 410, with the throw configurable to couple either the first input node 304 or the fourth input node 310 to the fifth output node 410. When the single-pole double-throw switch is connected in a first position, the first input node 304 and the fifth output node 410 are connected. When the single-pole double-throw switch is connected in a second position, the fourth input node 310 and fifth output node 410 are connected. The first input node 304 is coupled to the first output node. The second input node 306 is coupled to the second output node 404, the fourth output node 408 and the sixth output node 412. As noted previously, the second input node 306 may be referred to as a neutral input node 306. Coupling the neutral input node 306 to the second 404, fourth 408 and sixth 412 output nodes ensures that the neutral connection of the power system is coupled to the respective neutral connections of each of the three stacks 426-430 of the stack-based power converter 400. These couplings may be direct connections, such as conductive traces formed on a PCB without a switch coupled in the trace. The switch systems 502-508 may be used to configurably route input current from a single-phase, split-phase or three-phase power system to output nodes 402-412 of the configuration system 202. The switches allow current reduction in individual conductive paths of the configuration system 202 by splitting and recombining currents at internal nodes of the configuration system 202. This allows the higher-power / higher-current split-phase power system to be used without substantial changes to the current carrying ability of traces or paths within the configuration circuit. As previously noted, each stack 426-430 of the stack-based power converter 400 may operate independently. Each stack 426-430 may therefore be considered as a single-phase power converter. Whilst a single-phase or split-phase power system 102 may be coupled to a single one of the stacks 426-430, this may reduce the efficiency of the power converter’s 400 operation. In particular, the single stack would be required to convert the entire input current provided by the split-phase or single-phase system. This would also require the single stack of the stacks 426-430 to be rated to a high current, with the components used being both more expensive and bulkier, increasing the area of the stack-based power converter 400. The arrangement of the switch systems 502-508 allows equal-current routing of the current from the input nodes 304-310 to each of the stacks 426-430 of the stack-based power converter 400. By providing each of the stacks 426-430 with the same current, the stacks 426-430 can each provide the same power at their outputs. This means that the stacks do not have to be rated to carry the full input current provided to the input nodes 303-310, but rather only a portion of the current. This increases the efficiency of the power converter 400 and reduces the size of the power converter 400 through the ability to use lower-current rated components. The arrangement of single-pole single-throw and single-pole double-throw switches outlined in Figure 5a is an efficient switch arrangement to provide the configurable coupling for split-phase and three-phase power systems, whilst allowing equal current routing through the conductive paths and equal current sharing in each of the stacks 426-430. Other switch arrangements are possible, although these may require more switches or more complicated switching control. The switch systems 502-508 may comprise any apparatus suitable for coupling the specified nodes of the configuration system 204. Whilst the above description outlines specific single-pole single-throw and single-pole double-throw switches, other switch arrangements may be used. For example, the switch systems may comprise relays or switches, such as single-pole singlethrow switches, single-pole double-throw switches, double-pole double-throw switches. For example, the third switch system 506 may comprise a plurality of single-pole single-throw switches, such as a single-pole single-throw switch coupled between the first input node 304 and the third output node 406 and a single-pole single-throw switch coupled between the third input node 308 and the third output node 406. Similarly, the fourth switch system 508 may comprise a plurality of single-pole single-throw switch, such as a single-pole single-throw switch coupled between the first input node 304 and the fifth output node 410 and a single-pole single-throw switch coupled between the fourth input node 310 and the fifth output node 410. Any switch arrangement may be provided in the respective switch system which is capable of selectively coupling the respective nodes. The on-board charger 102 may include phase relays or safety relays - relays coupled in the direct current path from the input nodes 304-310 and used to decouple the input nodes 304-310 from the output of the stack-based power converter 400. Phase or safety relays may be included in each stack 426-430 of the stack-based power converter 400. These phase relays may form part of a pre-charge system of each stack. For example, relay 518 shown in Figure 4 may be part of the first stack 426. When the relay 518 is open, current is prevented from flowing through the stack 426 to the output. The second stack 428 and the third stack 430 may include similar phase relays. Including the phase relays in each stack 426-430 of the stack-based power converter allows the relays to be rated for a lower current, due to the equal current sharing operation of the configuration system, which ensures that the input current is shared equally between each stack 426-430. Further, the phase relay 518 may form part of the pre-charge circuit of the stack 426. As the phase relay 518 has a dual use (as a safety relay and a pre-charge relay) fewer relays are needed in the on-board charger than would typically be used. Whilst the phase relays are shown as part of the stack-based power converter 400, these are optional components. Alternatively, phase relays may be included in a different part of the on-board charger 102. Figure 5b shows configuration system 204 including phase relays 510-516. When the phase relays 510-516 are open, the input nodes 304-310 of the configuration system are decoupled from the output nodes 402-412. Opening the phase relays 510-516 may be in response to a safety warning, such as an incompatible power system coupled to the input nodes 304-310. Where the power system 104 is compatible with the on-board charger 102, the phase relays 510-516 may be closed, allowing current to flow between the input nodes 304-310 and output nodes 402-412 of the configuration system 204. Figure 6 is a schematic diagram showing the switch configuration when the input nodes 304-310 are coupled to a split-phase power system. The first switch 502 is closed between the first input node 304 and the third input node 308. The second switch 504 is closed between the second input node 306 and the fourth input node 310, The third switch system 506 is closed between the first input node 304 and the third output node 406. The fourth switch system 508 is closed between the first input node 304 and the fifth output node 412. By closing the switches in this manner, the first input node 304 and third input node 308 are coupled to the first output node 402, the third output node 406 and the fifth output node 410. The second input node 306 and fourth input node 310 are coupled to the second output node 404, the fourth output node 408 and the sixth output node 412. Coupling a first phase of the split-phase power system to the first input node 304 and third input node 308 and a second phase of the split-phase power system to the second input node 306 and fourth input node 310 allows all four of the input terminals 304-310 to be used, reducing the current in conductive traces of the configuration system 204. This coupling may be achieved using a portion of the wiring harness 602 of the vehicle 100. Further, by coupling the input nodes 304-310 to the output nodes 402-412 in this manner, all three stacks 426-430 of the stack-based power converter 400 are used, with an equal current routed from the input nodes 304-310 to each of the stacks 426-430. This allows the stacks to be 426-430 to be rated for a lower current, compared to a situation where the split-phase power system is coupled to a single stack. This reduces the current in each stack and allows the stacks 426-430 to operate with greater efficiency. A portion of the wiring harness or wiring loom 602 between the charging inlet 114 of the vehicle and the configuration system 202 couples a first power system node 604 to the first input node 304 and the third input node 308. The wiring harness or wiring loom 602 further couples a second power system node 606 to the second input node 306 and the fourth input node 310. The split-phase power system may then be coupled to the power system nodes 604 and 606. This link in the wiring harness or wiring loom 802 may be included in vehicles 100 intended for countries where split-phase charging is possible. The first power system node 604 may be, or may be connected to, a first phase of the split-phase system and the second power system node 606 may be, or may be connected to, a second phase of the split-phase system. In this way, two input nodes 308, 310. which would otherwise be redundant are used. Alternatively, the connections between the power system nodes 604 and 606 and the input nodes 304-310 may be a selectable or changeable connection which may be configured during use. The data input node 332 may receive information from the power system 104 as to the type of power system coupled to the input nodes 304-310. If the power system 204 is identified as a split-phase system, the control system may configure the selectable or changeable connection 602 such that it couples the power system nodes 604 and 606 and the input nodes 304-310. Further, the connections shown in wiring harness 602 may alternatively be provided by the power system 204 itself, external to the vehicle 100, or in the inlet 114 of the vehicle 100. Figure 7 is a schematic diagram showing the switch configuration when the input nodes 304-310 are coupled to a three-phase power system. The first switch 502 is open between the first input node 304 and the third input node 308. The second switch 504 is open between the second input node 306 and the fourth input node 310. The third switch system 506 is closed between the third input node 308 and the third output node 406. The fourth switch system 508 is closed between the fourth input node 310 and the fifth output node 410. By closing the switches in this manner, the first input node 304 is coupled to the first output node 402. The second input node 306 is coupled to the second output node 404, the fourth output node 408 and the sixth output node 412. The third input node 308 is coupled to the third output node 406. The fourth input node 310 is coupled to the fifth output node 410. Coupling a first phase of the three-phase power system to the first input node 304, a neutral phase of the three-phase power system to the second input node 306, a second phase of the three-phase system to the third input node 308 and a third phase of the three-phase system to the fourth input node 310 allows all four of the input terminals 304-310 to be used. By coupling the input nodes 304-310 to the output nodes 402-412 in this manner, all three stacks 426-430 of the stack-based power converter 400 are used, with an equal current routed from the input nodes 304-310 to each of the stacks 426-430. Each phase of the three-phase system is connected to a different one of the three stacks 426-430, and a neutral connection is also provided to each of the stacks 426-430. A portion of the wiring harness or wiring loom 702 between the charging inlet 114 of the vehicle 100 and the configuration system 204 couples the input nodes 304-310 to the power nodes 704-710 of the three-phase system. This connection in the wiring harness or wiring loom 702 may be included in vehicles 100 intended for countries where three-phase charging is possible. Alternatively, this connection may be a selectable or changeable connection which may be configured during use. The data input node 332 may receive information from the power system 104 as to the type of power system coupled to the input nodes 304-310. If the power system 204 is identified as a three-phase system, the control system may configure the selectable or changeable connections 702 such that they couple the power system nodes 704-710 and the input nodes 304-310. Where a permanent connection is included in the wiring harness or loom 602 to enable split-phase charging, as shown in Figure 6, it may not be possible to provide a connection as shown in the wiring harness or loom 702 of Figure 7 to provide three-phase charging, as including both connections would lead to a short-circuit of the three-phase power system. This may be considered acceptable as split-phase power systems are predominantly found in the US whilst three-phase power systems are predominantly found in Europe. As such, a different wiring harness may be used depending on the location the vehicle will be used in. However, providing a switchable connection in the wiring harness, where the switchable connection is changeable between the configuration of wiring harnesses 602 and 702 would allow the configuration system 204 to work with both split-phase and three-phase power systems. This may allow the same wiring harness 602, 702 to be used for both single-phase and three-phase power systems, with the connections of the wiring harness modified in dependence on the coupled power system type. A single-wiring harness may therefore be used across the world. Control of the switchable connections may be provided by the control system 330. Alternatively, the coupling of the input nodes 304-310 shown in the wiring harnesses or looms 602, 702 may be provided external to the vehicle 100, such as in the power system 104. This would allow the configuration system 204 to work with both three-phase and split-phase charging. Figure 8 is a schematic diagram showing the switch configuration when the input nodes 304-310 are coupled to a singlephase power system. The first switch 502 is open between the first input node 304 and the third input node 308, The second switch 504 is open between the second input node 310 and the fourth input node 314. The third switch system 506 is closed between the first input node 304 and the third output node 406. The fourth switch system 508 is closed between the first input node 304 and the fifth output node 410. By closing the switches in this manner, the first input node 304 is coupled to the first output node 402, the third output node 406 and the fifth output node 410. The second input node 306 is coupled to the second output node 404, the fourth output node 408 and the sixth output node 412. The third input node 308 and the fourth input node 310 are not coupled to any output nodes. Coupling a live phase of the single-phase power system to the first input node 304 and a neutral phase of the singlephase power system to the second input node 306 uses only two of the input terminals. Single-phase power systems are lower current systems when compared to split-phase systems, and as such use of more than two input terminals is not required. By coupling the input nodes 304 and 306 to the output nodes 402-412 in this manner, all three stacks 426-430 of the stackbased power converter 400 are used, with an equal current routed from the input nodes 304-310 to each of the stacks 426-430. The live connection of the single-phase system is connected all three of the stacks 426-430 and the neutral connection of the single-phase system is connected to all three of the stacks 426-430. This reduces the current in each stack and allows the stacks 426-430 to operate with greater efficiency. A portion of the wiring harness or wiring loom 802 between the charging inlet of the vehicle 100 and the configuration system 204 couples the input nodes 304-310 to the power system nodes 804 and 806 of the single-phase system. This link in the wiring harness or wiring loom 802 may be included in vehicles 100 intended for countries where single-phase charging is possible. Alternatively, this link may be a selectable or changeable link which may be configured during use. The wiring harness 802 shown in Figure 8 for the single-phase system may be the same as the wiring harness 702 shown in Figure 7 for the three-phase system, with power system node 804 corresponding to power system node 704 and power system node 806 corresponding to power system node 706. The positive and neutral phases would be coupled to power system nodes 704 / 804 and 706 / 806 respectively. As such, the wiring harness implementation 702 shown in Figure 7 is suitable for both single-phase and three-phase systems. In the preceding description, reference is made to a first input node 304, a second input node 306, a third input node 308 and a fourth input node 310. Where the configuration system 202 is coupled to electric vehicle supply equipment or a connector 112 capable of supplying a three-phase input, such as an EVSE which uses a CCS connector, the first input node is coupled to line 1 of the EVSE, the second input node 306 is coupled to the neutral of the EVSE, the third input node 308 is coupled to line 2 of the EVSE and the fourth input node 310 is coupled to line 3 of the EVSE. Where the configuration system 202 is coupled to electric vehicle supply equipment or a connector 112 capable of supplying a split-phase input, such as an EVSE which uses a NACS connector, the first input node is coupled to line 1 of the EVSE, the second input node 306 is coupled to line 2 of the EVSE, the third input node 308 is coupled to line 1 of the EVSE and the fourth input node 310 is coupled to line 2 of the EVSE. Figure 9 is a flowchart illustrating a method 900 according to an embodiment of the invention. The method 900 is a method of configuring power source connections to an on-board charging circuit of a vehicle 100, such as the vehicle 100 illustrated in Figure 1. The method 900 may be performed by the configuration system 202 illustrated in Figure 2 and in particular by the control system 330 shown in Figure 3, where the plurality of switches in the configuration system 202 are arranged as shown in any of Figures 5-8, In particular, the memory 338 may comprise computer-readable instructions which, when executed by the processor 336, perform the method 900 according to an embodiment of the invention. In a first step 902, Determine Power System (DPS), the method 900 comprises determining whether a power system 102 coupled to or that will be coupled to the configuration system 202 of the on-board charger 102 is a single-phase, split-phase or three-phase power system. This determination may be performed in a factory during calibration of the system, with the power system type chosen based on the country the vehicle 100 will be exported to, or the most likely power system 204 that the vehicle 100 is likely to be coupled to. The determination may be made when coupling the vehicle to an external power source or power system, especially when the connections in the wiring loom are suitable for or can be configured by the control system 330. In a second step 904, Configure Switches (CS), the method 900 comprises configuring the plurality of switches 320 of the configuration system 202 in dependence on the type of power system 204 coupled to the configuration system 202, or the type of power system 204 that will be coupled to the configuration system. If the plurality of input nodes 304-310 are coupled to, or will be coupled to, a split-phase power system, the configuration of the switches is modified such that the switching circuit couples at least one redundant input node of the plurality of input nodes 304-310 with at least one output node of the plurality of output nodes 402-412. The switches 502-508 are switched as indicated in the below table. Connections between the input nodes 304-310 and the power system are configured as shown in the wiring harness 602 of Figure 6. As such, the wiring harness 602 is configured to connect the first input node 304 to the third input node 308 and the second input node 306 to the fourth input node 310. As explained previously, these connections may be hard-wired or permanent connections in the wiring harness or wiring loom 602 of the vehicle. A first live connection is provided from the power system 104 to the first input node 304 and the third input node 308, a second live connection is provided from the power system 104 to the second input node 306 and the fourth input node 310. The connections shown as part of the wiring harness may be provided by the power system 104, or provided in the inlet 114 of the vehicle. Further, where the connections in the wiring harness 602 are configurable or changeable, the method may include modifying the connections of the wiring harness 602 such that they are suitable for a split-phase system. If the plurality of input nodes are coupled to, or will be coupled to, a three-phase power system, the configuration of the switches 502-508 is modified as shown in the below table. Connections between the input nodes 304-310 and the power system are configured as shown in the wiring harness 702 of Figure 7. As explained previously, these connections may be hard-wired or permanent connections in the wiring harness or wiring loom 702 of the vehicle. A first live connection is provided from the power system 102 to the first input node 304, a neutral connection is provided from the power system 104 to the second input node 306, a second live connection is provided from the power system 104 to the third input node 308 and a third live connection is provided from the power system 104 to the fourth input node 310. The connections shown as part of the wiring harness may be provided by the power system 104, or provided in the inlet 114 of the vehicle. Further, where the connections in the wiring harness 702 are configurable or changeable, the method may include modifying the connections such that they are suitable for a three-phase system. If the plurality of input nodes are coupled to, or will be coupled to, a single-phase power system, the configuration of the switches 502-508 is modified as shown in the below table. Connections between the input nodes 304 and 308 and the power system are configured as shown in the wiring harness 802 of Figure 8. As explained previously, these connections may be hard-wired or permanent connections in the wiring harness or wiring loom 802 of the vehicle. A first live connection is provided from the power system 102 to the first input node 304, a neutral connection is provided from the power system 102 to the second input node 306. Alternatively, the wiring harness of the three-phase system 702 may also be used for the single-phase system. The connections shown as part of the wiring harness may be provided by the power system 104, or provided in the inlet 114 of the vehicle. Further, where the connections in the wiring harness 802 are configurable or changeable, the method may include modifying the connections such that they are suitable for a three-phase system. Configuring the switches may comprise coupling the input nodes of the configuration system with the output nodes of the configuration system, and in particular, coupling the switches of the configuration system in accordance with the below table: Power system type Switch one 502 Switch two 504 Switch three 506 Switch four 508 Single-Phase Open or Closed Open Closed between first input node and third output node Closed between first input node and fifth output node Split-Phase Closed Closed Closed between first input node and third output node Closed between first input node and fifth output node Three-Phase Open Open Closed between third input node and third output node Closed between fourth input node and fifth output node The follow numerals may be used in combination with the figures to aid understanding: EMI Input Filter 1 4000 Pre-charge L1 4010 EMI Input Filter 2 4020 Single Stage OBC 4030 EMI Input Filter 3 4040 EMI Input Filter 4 4050 Pre-charge L2 4060 EMI Input Filter 5 4070 EMI Input Filter 6 4080 Pre-charge L3 4090 Output EMI filter 4100

Claims

1. A configuration system for an on-board charging circuit of a vehicle, the configuration system comprising:a plurality of input nodes for coupling to a split-phase power system or a three-phase power system;a plurality of output nodes for coupling to a power converter of an on-board charging circuit;a plurality of switches coupled between the plurality of input nodes and the plurality of output nodes,wherein the configuration system is configured to:determine whether a power system to be coupled to the plurality of input nodes is a split-phase power system or a three-phase power system;modify a configuration of the switches, wherein if the plurality of input nodes are to be coupled to a splitphase power system, the configuration of the switches is modified such that the switching circuit couples at least one redundant input node of the plurality of input nodes with at least one output node of the plurality of output nodes.

2. The configuration system according to claim 1, wherein the plurality of input nodes comprise a first input node, a second input node, a third input node and a fourth input node; andwherein modifying the configuration of the switches when the plurality of input nodes are to be coupled to a splitphase power system comprises coupling a first phase connection of the split-phase power system to the output nodes using the first input node and the third input node and a second phase connection of the split-phase power system to the output nodes using the second input node and the fourth input node.

3. The configuration system according to any preceding claim, wherein the plurality of output nodes comprise a first output node, a second output node, a third output node, a fourth output node, a fifth output node and a sixth output node for coupling to a three-phase stack AC-DC converter.

4. The configuration system according to claim 3, comprising:a first switch coupled between the first input node and the third input node;a second switch coupled between the second input node and the fourth input node;a third switch system to couple either the first input node or the third input node to the third output node;a fourth switch system to couple either the first input node or the fourth input node to the fifth output node.

5. The configuration system according to claim 4, wherein, when the input nodes are configured to be coupled to a split-phase power system:the first switch is closed;the second switch is closed;the third switch system is closed between the first input node and the third output node;the fourth switch system is closed between the first input node and the fifth output node.

6. The configuration system according to claim 4 or claim 5, wherein, when the input nodes are configured to be coupled to a three-phase system:the first switch is open;the second switch is open;the third switch system is closed between the third input node and the third output node; the fourth switch system is closed between the fourth input node and the fifth output node.

7. The configuration system according to any of claims 4 to 6, wherein when the input nodes are configured to be coupled to a single-phase system:the second switch is open;the third switch system is closed between the first input node and the third output node;the fourth switch system is closed between the first input node and the fifth output node.

8. The configuration system according to any of claims 3 to 7, wherein the first input node is coupled to the first output node.

9. The configuration system according to any of claims 3 to 8, wherein the second input node is coupled to the second, fourth and sixth output nodes.

10. An on-board charger system for a vehicle, the on-board charger comprising: the configuration system according to any preceding claim; anda three-phase stack AC-DC converter coupled to the plurality of output nodes of the charging configuration circuit.

11. The on-board charger system for a vehicle according to claim 10, wherein the configuration system is configured to provide an equal current to respective stacks of the three-phase stack AC-DC converter when the plurality of input nodes are coupled to a split-phase power system or a three-phase power system.

12. The on-board charger system according to claim 10 or 11, wherein:the first and second output nodes are coupled to a first stack of the stack AC-DC converter;the third and fourth output nodes are coupled to a second stack of the stack AC-DC converter;the fifth and sixth output nodes are coupled to a third stack of the stack AC-DC converter.

13. A vehicle comprising either:the configuration system according to any of claims 1-9; orthe on-board charger system according to any of claims 10-12.

14. The vehicle according to claim 13, further comprising:a charging inlet;a wiring loom coupled between the charging inlet and the configuration system, the wiring loom comprising: a conductive link coupling the first input node and the third input node; and a conductive link coupling the second input node and the fourth input node.

15. A method of configuring power system connections to an on-board charging circuit of a vehicle, the method comprising:determining whether a power system to be coupled to a plurality of input nodes of a configuration system is a splitphase power system or a three-phase power system;modifying a configuration of a plurality of switches of the configuration system, wherein if the plurality of input nodes are to be coupled to the split-phase power system, the configuration of the switches is modified such that the plurality 5 of switches couple at least one redundant input node of the plurality of input nodes with at least one output node of the plurality of output nodes.

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