Power supply circuit

Abstract

Aspects of the present invention relate to a power supply circuit for an electric vehicle, the power supply circuit comprising an AC charging configuration and a DC high voltage load supply configuration, the power supply circuit comprising an on-board charger switchable between the AC charging configuration and the DC high voltage load supply configuration.

Description

[0001] POWER SUPPLY CIRCUIT

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to a power supply circuit, and more specifically to a power supply circuit for an electric vehicle. Aspects of the invention relate to a power supply system, a method, a controller, and a vehicle.

[0004] BACKGROUND

[0005] Battery-powered vehicles (cars, vans lorries, etc) are rapidly increasing in number. Conventional systems for supporting charging of batteries in electric vehicles can be complex, and may use different charging connection standards. Various loads in the electric vehicle may still need to be supplied during the charging process, for example when these are required to support efficient battery charging.

[0006] It is an aim of the present invention to address at least some of the disadvantages associated with the prior art.

[0007] SUMMARY OF THE INVENTION

[0008] Aspects and embodiments of the invention provide a power supply circuit for an electric vehicle, a method for providing power to high voltage loads in an electric vehicle and a vehicle as claimed in the appended claims.

[0009] In a broad aspect of the present invention, there is provided means to repurpose a charger circuit to provide a boost circuit to support high voltage loads.

[0010] According to an aspect of the present invention there is provided a power supply circuit for an electric vehicle, the power supply circuit comprising an AC charging configuration and a DC high voltage load supply configuration, the power supply circuit comprising an on-board charger switchable between the AC charging configuration and the DC high voltage load supply configuration. This approach allows for an on-board charger present for AC charging to be repurposed during DC high- voltage charging in order to provide DC / DC boost capability to high-voltage loads normally powered by the vehicle’s battery packs without the need to provide additional circuitry in the vehicle. This can be particularly important to service high-voltage loads that are needed during a battery charging process.

[0011] In an embodiment of the power supply circuit, the on-board charger comprises two transistors connected in series across a capacitor, wherein a source providing an input current is connected between the two transistors via an inductor. This circuit configuration enables the on-board charger to perform the voltage boost. In one such embodiment, the two transistors are MOSFET transistors and wherein the power supply circuit is adapted such that the duty cycle of the MOSFET transistors maintains the voltage across the capacitor above a set value. This allows for the voltage provided by the on-board charger to be within an optimal value in accordance with the operating conditions of the high-voltage loads connected to the battery packs, to maintain the voltage below a maximum value that may result in an inefficient operation, and above a minimum value to avoid operating at higher currents.

[0012] In embodiments the on-board charger comprises an isolating component. This allows for the use of the on-board charger to provide galvanic isolation to the high-voltage loads to isolate that part of the circuit from the part of the circuit connected to a charging station during fast DC charging. Optionally, the isolating component is a transformer. In other embodiments, the on-board charger comprises a dual active bridge. This enables the power supply circuit to provide galvanic isolation to the high- voltage loads. In yet another embodiment, the dual active bridge comprises a capacitor-inductor- inductor-capacitor, CLLC, structure. This allows the power supply circuit to have a bidirectional functionality of power transfer that, allows the on-board charger to operate in forward mode during DC charging.

[0013] According to a further aspect of the present invention there is provided a power supply system comprising the power supply circuit of any of the preceding aspects, the power supply system further comprising a first battery pack and a second battery pack switchable between a first DC high-voltage load supply configuration to provide a lower voltage and a second DC high-voltage load supply configuration to provide a higher voltage. Optionally, the higher voltage is substantially 800V and the lower voltage is substantially 400V, the power supply further comprising a DC high voltage load bus at substantially 800V connected to the DC high voltage load supply configuration. This allows for the power supply circuit to be adjusted according to the voltage provided by the charging station connected to the power supply circuit.

[0014] In embodiments, the power supply system further comprises a set of one or more switches to connect the power supply system in the first DC high-voltage load supply configuration to a DC high-voltage load bus via the power supply circuit, wherein in the first DC high-voltage load supply configuration, the first battery pack (316) and the second battery pack (318) are connected in parallel. This allows high-voltage loads to be supported effectively even when the battery system is configured to provide a lower DC value. Optionally, when the power supply system is in the second DC high-voltage load supply configuration the first battery pack (316) and the second battery pack (318) are connected in series. When the switches are closed during DC fast charging, they provide a bypass path, that allows a limited amount of power to flow to the on-board charger in its DC high-voltage load supply configuration to ensure that the high-voltage loads receive enough power.

[0015] In embodiments, the set of one or more switches is further configured to disconnect the power supply circuit from the DC high-voltage load bus when the power supply system is in the second DC high- voltage load supply configuration. This allows for different parts of the power supply circuit to be powered depending on the charging voltage, and specifically for the on-board charger to receive power supply only when required.

[0016] According to a further aspect of the invention, there is provided a method for providing power to high voltage loads in an electric vehicle, wherein the electric vehicle has a first battery pack and a second battery pack switchable between a series arrangement and a parallel arrangement and at least an AC charging configuration for charging the first and second battery packs, the method comprising connecting the first battery pack and the second battery pack in parallel, and switching an on-board charger from the AC charging configuration to a first high voltage DC charging configuration to power high voltage DC loads.

[0017] Such a method is particularly effective for allowing the on-board charger to be repurposed during fast DC charging, to provide power to high-voltage loads that are normally powered by the battery packs.

[0018] In embodiments, the electric vehicle further comprises at least a second high voltage DC charging configuration for charging the first and second battery packs, and wherein switching the on-board charger from the AC charging configuration to the high voltage DC charging configuration takes place during use of the first high voltage DC charging configuration to charge the first battery pack and the second battery pack. This enables the method to provide power to the on-board charger only when needed, in order to supply power to the high-voltage loads.

[0019] According to yet a further aspect of the invention, there is provided a controller for controlling a power supply circuit of an electric vehicle, the controller comprising a processor having a memory configured to store instructions that when executed instruct the controller to perform the method of according to the preceding aspects.

[0020] According to a still aspect of the invention, there is provided a vehicle comprising the power supply vehicle and the controller of the preceding aspects. 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.

[0021] BRIEF DESCRIPTION OF THE DRAWINGS

[0022] One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0023] Figure 1 shows a schematic diagram of the electric vehicle charging system, according to embodiments of the present disclosure.

[0024] Figure 2 shows schematic diagram of part of the power supply circuit corresponding to the on-board charger, according to embodiments of the present disclosure.

[0025] Figure 3 shows schematic diagram of a system that uses the power supply circuit according to embodiments of the present invention.

[0026] Figure 4 shows a schematic of the connection box for Ell CCS standard and US NACS standard. Figures 5A and 5B show a schematic diagram of the circuit for the DC / DC converter, according to embodiments of the present invention.

[0027] DETAILED DESCRIPTION

[0028] Generally, the disclosure herein relates to a power supply circuit for an electric vehicle, where the power supply circuit has an AC charging configuration and a DC high voltage load supply configuration. The power supply circuit additionally comprises a on-board charger that can be switched between an AC charging configuration and a DC high voltage charging configuration.

[0029] Figure 1 shows a schematic diagram of a system 100 according to embodiments of the present invention. As shown in Figure 1 , the system 100 comprises an electric vehicle 102 and a charging system 104 connected to an electric vehicle supply equipment (EVSE) (i.e., charging station) 106. Here, the charging system 104 comprises an AC charging system - referred to below as an onboard charger (OBC) 104a - and a DC charging system 104b. The charging system 104 may be provided entirely within the electric vehicle 102 or may be provided in part as an external unit for connection to the electric vehicle 102. The electric vehicle 102 may comprise at least one battery pack 108 that may be connected to the on-board charger 104a. The electric vehicle 102 has one or more high-voltage (HV) loads 110. In normal operation, these will be powered from the battery pack 108. As will be described below, in certain situations these can be powered using circuitry from the on-board charger 104a. The charging system 104 also comprises a controller 1040 having a processor with a memory, for configuration of the circuitry of the charging system 104.

[0030] An on-board charger is commonly used in electric vehicles for converting an alternating voltage (AC) current supply into a charging direct current (DC), both for single phase and three phase charging. The DC current after conversion is used to charge the vehicle battery packs. On conversion from mains AC voltage to DC, boost conversion is required to bring the DC voltage up to a voltage suitable for charging the battery packs. It is an aim of the present invention to repurpose the OBC to provide this DC / DC boost capability to provide power to at least some of the high-voltage loads normally powered from the battery packs. This may be required in particular during DC charging using the DC charger 104b, in particular when the DC charger 104b is only capable of operating at a “low” DC voltage, typically 400V (first high voltage DC), rather than a “high” DC voltage, typically 800V (second high voltage DC), in which case the electric vehicle system (EVSE and battery packs) will be configured so that only power at this “low” DC voltage (typically 400V) will be available.

[0031] Figure 2 shows a schematic diagram of part of the power supply circuit 200 corresponding to the onboard charger, according to embodiments of the present disclosure. It is to be appreciated that the structure of the power supply circuit 200 described herein is provided as an example and other structures providing the same functionality as the on-board charger described herein may also be used.

[0032] As shown in Figure 2, the circuit comprises two power converter circuits connected in series. The first converter 202 comprises the circuit defined by a dashed line, at the left of capacitor 220, and the second converter 204 comprises the circuit defined by a grey box, at the right of capacitor 220. The capacitor 220 acts as a DC link between the first converter 202 and the second converter 204.

[0033] The first converter 202 comprises a power factor correction circuit (PFC) which when in its normal state and connected directly to an AC charging configuration, has the function of removing harmonic distortion in the supply current, to provide a current waveform that is close to a basic sine wave. The PFC stage typically operates in boost mode to control the input voltage and comprises at least two transistors connected to the AC charging configuration through at least one inductor. The transistors used herein are preferably metal-oxide-semiconductor field-effect transistors (MOSFET), however, other transistors providing the same functionality may also be used in the present disclosure, such as for example, Gallium Nitride (GaN) transistors or Insulated Gate Bipolar Transistor (IGBT). In embodiments of the present disclosure, this circuit is repurposed to provide a power feed to certain high-voltage loads, as will be described further below. In this situation, the inductor of the PFC circuit in combination with the MOSFET transistors is used to provide DC / DC boost to increase the voltage that can be provided to the high-voltage loads, and in this operation mode the duty cycle of the MOSFET transistors may be adjusted to maintain the voltage across the DC link provided by the capacitor 220 to or above a set value, that may be, for example, but not limited to 650 V. The relation between the voltage and the duty cycle (D) of the MOSFET transistors when the inductor of the PFC circuit is being used to perform such DC boosting is provided by Eq.1 below.

[0034] , Vin

[0035] Vout = - Eq. 1

[0036] (l-P)

[0037] In the system 200, during a DC / DC boost operation of the PFC circuit, the output voltage (Vout) is fixed and may be set at, for example 650V. As will be described below, this will typically be a sufficiently high voltage to power relevant high-voltage loads. The second converter 204 may therefore not provide further boost but may provide galvanic isolation through transformer 260. Therefore, according to Eq. 1 , during the DC / DC boost operation to provided power to high-voltage loads, the duty cycle (D) is controlled by adjusting the input voltage (Vin), which in DC charging corresponds to the DC voltage provided by the charging station (i.e., EVSE), and which is also connected to the battery packs to charge them. In this condition, the Vin may vary as the battery is charged. Accordingly, in order to maintain the Vout fixed, if the Vin varies linearly, the duty cycle (D) must be controlled. As such, the duty cycle is varied, depending on the Vin, to maintain the same Vout throughout the battery pack charging process. Accordingly, the difference between the input voltage and the output voltage at the second converter 204 may be maintained within a predetermined range.

[0038] The DC current output from the first converter 202 goes through the capacitor 220, which smooths the voltage provided by the first converter 202 and provides a buffer between the intermediate DC voltage outputted by the first converter 202 to the second converter 204, where the voltage will be adjusted to provide correct DC levels. In the conventional use of the OBC, this will be to provide a correct charging level to the vehicle battery pack. In the repurposed case, this will be to provide a correct voltage level to the high-voltage DC loads. Therefore, the second converter 204 acts as a DC / DC on-board charger. It is to be appreciated that although Figure 2 only provides one capacitor for the DC link, that the DC link may alternatively comprise a plurality of capacitors. The second converter 204 may comprise a structure of a dual active bridge converter, as illustrated in Figure 2, where a transformer is used to provide galvanic isolation. Where the OBC 104a is connected for AC charging, this may be used for bidirectional power flow, allowing bidirectional power transfer between the electric vehicle and the power grid connected to the first converter 202. As shown in Figure 2, the second converter 204 is composed of two full-bridge circuits connected by an isolated component, such as for example a transformer, and additional inductors 254 and 262. The left-side full-bridge is connected to the PFC while in its normal AC charging operation the rightside full-bridge is connected to the electric vehicle battery pack (not shown). The dual active bridge converter of Figure 2 has a capacitor-inductor-inductor-capacitor, CLLC, structure, which in its normal AC charging operation, in addition to providing the bidirectional functionality of power transfer, also provides high power density to the electric vehicle battery pack.

[0039] When repurposed to provide power to the high-voltage loads, the on-board charger operates only in “forward mode” when power flows from the DC changing bus connected to the first converter 202, to provide energy to the high-voltage loads, when the battery packs are connected to a 400V DC charging station. In the circuit 200 shown in Figure 2, the voltage across the DC link 220 may then be fixed at, for example but not limited to 650V, and the second converter 204 is set to primarily provide galvanic isolation. In this condition, the efficiency in the conversion of the second converter 204 may be varied from approximately 0.85 to 1.35, by controlling which MOSFETS of the second converter 204 are switched on or off.

[0040] Figure 3 provides a schematic diagram of a system that uses the power supply circuit according to embodiments of the present invention. In Figure 3 a circuit is shown having two electric vehicle battery packs (316 and 318), which may be connected in series or parallel, and a portion corresponding to the on-board charger, which is connected to HV loads. Here the battery packs may correspond to two 400V battery packs. It is to be appreciated that, although only two battery packs are shown, the system in Figure 3 may alternatively present one or more battery packs. In addition, although Figure 3 shows the system connected to a DC fast charging station (DCFC) it should be appreciated that the same circuit may alternatively be connected to an AC charging station, for example when the batteries are being charged using a North American Charging Standard (NACS) system.

[0041] The on-board charger of Figure 2 may therefore be switched out of the AC charging circuit and used in the system shown in Figure 3 to provide high voltage supply to HV loads connected to the onboard charger, while the electric vehicle batteries are being charged using DC fast charging. In known electric vehicles, the on-board charger is used when performing AC charging of electric vehicle battery packs, in order to regulate the voltage and current reaching the battery packs. During DC fast charging, the AC / DC conversion is performed before the voltage is supplied to the electric vehicle, and therefore, the power is supplied directly to the battery packs, meaning that the normal function of the on-board charger is not required.

[0042] The system provided by Figure 3 enables battery pack 316 and battery pack 318 to be connected in series, when performing AC charging or DC charging at 800V, and in parallel, when performing DC charging at 400V. As shown in Figure 3, points 308 and 310 measure the voltage of the EVSE connected to the battery packs. Once the voltage is determined, the system then configures the connection between the EVSE and the battery packs for the particular charging station. When the EVSE is at 400V then the switches 304 and 306 are closed and switch 302 is opened, to configure battery pack 316 and battery pack 318 in parallel. Similarly, when the voltage of the EVSE is determined to be at 800V, then switch 302 is closed and switched 304 and 306 are opened, to provide a series configuration between battery pack 316 and battery pack 318. Therefore, configuration of battery pack 316 and battery pack 318 during charging will depend on the voltage provided by the EVSE.

[0043] In Figure 3, the portion of the system 300 within the dashed line can be configured for 800V or 400V depending on the EVSE connected to the battery packs. However, the portion of the system 300 that is outside of the dashed line always operates at 800V due to the HV load connected to that portion of the system 300. Therefore, with exception to the inverter, the rest of the DC / DC system, such as high-voltage heater, high-voltage e-air conditioning, necessary to precondition the batteries, and high voltage-low voltage DC / DC converter need 800V to operate. It is at least desirable, and in some embodiments, may be necessary for these HV loads to be powered during DC charging. In order for the system to operate the HV loads while performing a 400V DC fast charging, there is a need to boost the voltage from 400V DC to 800V DC, while the battery packs are directly connected to an EVSE at 400V.

[0044] Known systems usually use an additional DC / DC converter to provide the additional voltage boost needed for the HV load. The inventors of the present disclosure have identified that, during a DC charging operation of the battery pack, it is possible to repurpose the onboard charger to boost the voltage and perform power conversion to the high voltage accessories connected to the battery packs that operate at 800V. Using this approach, a small amount of power can be diverted to providing 800V (or similar - 650V may in practice be sufficient) for the HV loads while charging at 400V. This may be particularly important when the HV loads include. Therefore, when battery pack A and battery pack B are directly connected to an EVSE at 400V, and are operating in a parallel configuration, switches 206 and 208 or switches 212 and 208 (Figure 2) are closed to allow a small amount of power to flow to the on-board charger, to ensure that the HV loads receive enough power. This solution provides a bypass path, while the battery is charging at 400V, that allows a limited amount of power (e.g., less than or equal to 15 KW) to be fed to the HV loads, which is the power needed to maintain the HV loads operable to pre-condition the HV batteries. Accordingly, the method proposed in the present disclosure aims at repurposing the onboard charger during DC fast charging, to boost the voltage and perform the power conversion to the accessories connected to the battery packs. One of the advantages provided by this solution is that the EVSE provides input directly into the battery, without any power conversion, and only the amount of power needed to run the rest of the high voltage accessories need be converted. Using power conversion through the onboard charger is a particularly effective solution, since the onboard charger circuitry is able to provide the power required by the high-voltage loads within the electric vehicle (e.g., HV heater, HV eAC and HV-LV DC / DC).

[0045] It is noted that when battery pack 316 and battery pack 318 are connected in series, that is, when the battery packs are connected directly to an EVSE of 800V, the HV load connected to the on-board charger may operate from anywhere around 450V to 870V - typically, HV loads will be adapted to operate across this input range. On the other hand, when battery pack 316 and battery pack 318 are connected in parallel, that is, when the battery packs are connected directly to an EVSE of 400V, the HV load connected to the on-board charger would need to operate from anywhere between 250V to 450V, depending on the state of charge of the battery packs, and the lower voltages would be insufficient - use of the solution provided by embodiments of the invention ensures that the HV loads - which may include loads needed to ensure effective charging of the battery - see a voltage that will enable them to function normally.

[0046] As shown in Figure 2, the power supply circuit 200 further comprises switches 206, 208, 210, 212 that provide the connection in between the high voltage DC current and the AC charging configuration from the charging inlet. When performing conventional single and 3 phase AC charging, switches 206, 208, 210, 212 will remain open. If 800V DC charging is provided, this circuitry may not be required - it is not needed for AC charging and it is not needed in order to provide power to the HV DC loads, as the EVSE is providing 800V and the battery pack is in series configuration. However, when 400V DC charging is being performed, switches 206, 208, 210, 212 will close to allow the voltage to go through the on-board charger to the high-voltage loads, where high voltage is, for example 800V. Accordingly, during 400V charging where the power supply circuit 200 has been repurposed to provide boost conversion to support 800V DC loads, the on-board charger circuitry operates to control the voltage reaching the MOSFET transistors in the first converter 202 such that the dutycycle of the MOSFET transistors can vary so as to maintain the voltage of the DC link around and above a predetermined set value, such as for example of about 650V. The set value is determined taking into account the optimal operating conditions for the HV loads, which typically is below the maximum operating value of the battery packs (e.g., 800V), and above a minimum value to avoid operating at high currents. Accordingly, the voltage output obtained from the first converter 202 is equal to the input voltage over one duty cycle of the at least two MOSFET transistors comprising the first converter 202. In addition, once the DC link provided by capacitor 220 is charged to a voltage greater than that of the predetermined set value (e.g., around 650V), the high voltage to high voltage converter (provided by the second converter 204) boosts the voltage is used to provide an isolated HV DC output for the high voltage loads of the electric vehicle. The output voltage is set to be sufficient to achieve safe operation of the high voltage components connected to the battery packs, such as HV heater, e-air conditioning and HV-LV DCDC - this may involve provision of a further voltage boost if the second converter 204 is set appropriately, but it need not (for example, in cases where the second converter 204 is used essentially to provide galvanic isolation).

[0047] During operation of the 400V to 800V conversion the first stage of the on-board charger circuit operates as a non-isolated DC / DC on-board charger, as shown in figure 5A. In the circuit provided in figure 5A, Vin is the EVSE connection, capacitor 502 is the capacitor from the battery pack and inductor 504 corresponds to the inductors 214, 216 and 218 in figure 2. In addition, capacitor 506 (figure 5A) corresponds to capacitor 220 (figure 2), transistor 508 (figures 5A and 5B) corresponds to transistors 224, 228, 232 (figure 2), and transistor 510 (figures 5A and 5B), corresponds to transistors 222, 226 and 230 (figure 2). Described herein having as basis the circuits provided in figure 5A, the operation of the circuit to provide the power boost from the OBC has an initial step where the current is allowed to flow through the transistor 508 to charge the inductor 504, this is achieved by, for example, closing switches 206 and 210 in figure 2. At a second and subsequent step, once the inductor has been charged, the current is allowed to go through transistor 510. At this second step, the transistor 510 receives the power from Vin (i.e. , the EVSE) and inductor 504, which is then used to charge capacitor 506 that receives a boosted power resulting from the combination of the power from Vin and 504. In addition, during the whole operation, switch 208 remains closed to allow the current to go through transistor 236, which closes the circuit and provides a return path to the current. However, the actual output that will be provided to the HV loads is isolated, because there is an HV-HV converter - second converter 204, which contains transformer 260 and therefore provides isolation - in between the non-isolated DC / DC on-board charger (first converter 202), and the HV loads. Advantageously, the galvanic isolation provided by the transistor of the dual active bridge converter of the second converter 204 can be used to galvanically isolate the 400V DC bus linked to an 800V DC bus, during fast DC charging.

[0048] The galvanic isolation provided by the dual active bridge enables isolating the 400V side from the 800V side during DC fast charging. This can be achieved by disconnecting the main connection paths through switches provided in the master contacts for the bus. These switches are illustrated by switches 312 and 314 in Figure 3. Therefore, the EVSE and the charger only see the isolated part of the AC / DC converter and the battery, which are completely disconnected from the 800V bus.

[0049] When charging electric vehicles different types of standard types of connectors are used, such as the Combined Charging System (CCS). It can use Combo 1 (CCS1) or Combo 2 (CCS2) connectors to provide power at up to 350 kilowatts (kW). These two connectors are extensions of standard Type 1 and Type 2 connectors, with two additional direct current (DC) contacts to allow high-power DC fast charging.

[0050] The Combined Charging System allows AC charging using the Type 1 and Type 2 connector depending on the geographical region. In addition, the system illustrated in Figure 2, provides two switches, 402 and 404 that connect the AC charging bus and DC charging bus to the on-board charger and the battery packs. These switches can be connected and disconnected, depending on the type of charge being performed, and therefore enables fast DC charging using the US NACS connection standard. This is due to the fact that CCS has separate pins for delivering AC current and DC current power during charging, while NACS leverages the same pin for both AC and DC. Therefore, by providing the switches at the AC / DC charging bus, different currents may be delivered to the same connection pins. Figure 4 provide a schematic diagram of the circuit that enables the connection for EU CCS standard and US NACS standard.

[0051] Within the context of the present disclosure, where a structural feature has been described, it may be replaced by means for performing one or more of the functions of the structural feature whether that function or those functions are explicitly or implicitly described herein.

[0052] In this description, reference has been made to various embodiments. The description of features or functions in relation to an embodiment indicates that those features or functions are present in that embodiment. The use of the term “embodiment”, “example” or “for example” or “may” in the text denotes, whether explicitly stated or not, that such features or functions are present in at least the described embodiment, whether described as an embodiment or not, and that they can be, but are not necessarily, present in some of or all other embodiments. Thus, “embodiment”, “example”, “for example” or “may” refers to a particular instance in a class of embodiments. A property of the instance can be a property of only that instance or a property of the class or a property of a subclass of the class that includes some but not all of the instances in the class. It is therefore implicitly disclosed that features described with reference to one embodiment but not with reference to another embodiment, can where possible be used in that other embodiment but does not necessarily have to be used in that other embodiment.

[0053] Although embodiments of the present disclosure have been described in the preceding paragraphs with reference to various examples, it should be appreciated that modifications to the examples given can be made without departing from the scope of the disclosure as claimed.

[0054] Features described in the preceding description may be used in combinations other than the combinations explicitly described herein.

[0055] Although functions have been described with reference to certain features, those functions may be performable by other features whether described or not.

[0056] Although features have been described with reference to certain embodiments, those features may also be present in other embodiments whether described or not.

[0057] It will be appreciated that various changes and modifications can be made to the present disclosure without departing from the scope of the present application.

[0058] Text in table 1 may be used in combination with the relevant numerals contained within the figures.

[0059] Table 1

Claims

CLAIMS1 . A power supply circuit for an electric vehicle, the power supply circuit comprising an AC charging configuration and a DC high voltage load supply configuration, the power supply circuit comprising an on-board charger switchable between the AC charging configuration and the DC high-voltage load supply configuration.

2. The power supply circuit of claim 1 , wherein the on-board charger comprises: two transistors connected in series across a capacitor, wherein a source providing an input current is connected between the two transistors via an inductor.

3. The power supply circuit of claim 2, wherein the two transistors are MOSFET transistors and wherein the power supply circuit is adapted such that the duty cycle of the MOSFET transistors maintains the voltage across the capacitor above a set value.

4. The power supply circuit of any preceding claim, wherein the on-board charger comprises an isolating component.

5. The power supply circuit of claim 4, wherein the isolating component is a transformer.

6. The power supply circuit of claim 5, wherein the on-board charger comprises a dual active bridge.

7. The power supply circuit of claim 6, wherein the dual active bridge comprises a capacitor-inductor- inductor-capacitor, CLLC, structure.

8. A power supply system for an electric vehicle comprising the power supply circuit of any of claims 1 to 7, the power supply system further comprising a first battery pack and a second battery pack switchable between a first DC high-voltage load supply configuration to provide a lower voltage and a second DC high-voltage load supply configuration to provide a higher voltage.

9. The power supply system of claim 8, further comprising a set of one or more switches to connect the power supply system in the first DC high-voltage load supply configuration to a DC high-voltage load bus via the power supply circuit, wherein in the first DC high-voltage load supply configuration, the first battery pack and the second battery pack are connected in parallel.

10. The power supply system of claim 9, wherein when the power supply system is in the second DC high-voltage load supply configuration the first battery pack and the second battery pack are connected in series.

11. The power supply system of any of claim 10, wherein the set of one or more switches is further configured to disconnect the power supply circuit from the DC high-voltage load bus when the power supply system is in the second DC high-voltage load supply configuration.

12. A method for providing power to high voltage loads in an electric vehicle, wherein the electric vehicle has a first battery pack and a second battery pack switchable between a series arrangement and a parallel arrangement and at least an AC charging configuration for charging the first battery pack and second battery pack, the method comprising connecting the first battery pack and the second battery pack in parallel, and switching an on-board charger from the AC charging configuration to a first high voltage DC charging configuration to power high voltage DC loads.

13. The method of claim 12, wherein the electric vehicle further comprises at least a second high voltage DC charging configuration for charging the first battery pack and second battery pack, and wherein switching the on-board charger from the AC charging configuration to the high voltage DC charging configuration takes place during use of the first high voltage DC charging configuration to charge the first battery pack and second battery pack.

14. A controller for controlling a power supply circuit of an electric vehicle, the controller comprising a processor having a memory configured to store instructions that when executed instruct the controller to perform the method according to claims 12 and 13.

15. A vehicle comprising the power supply system of claims 8 to 11 and the controller of claim 14.

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