Power system control

Abstract

A control system (200-Fig.2) controls a vehicle power system 400 that comprises: at least one high voltage (HV) battery pack 410, at least one primary DC-DC converter 420, 422, and at least one secondary DC-DC converter 424. The HV battery pack is electrically connected to a low voltage (LV) bus 460 via the primary DC-DC converter(s), and selectively electrically connected via the secondary DC-DC converter(s). The control system receives load information indicative of a power supply requirement of the LV bus. In dependence on the received load information, the control system determines and outputs a control signal for each of the DC-DC converters, to control the primary DC-DC converter(s) to supply power from the HV battery pack(s) to the LV bus, and control the secondary DC-DC converter(s) to supply power from the HV battery pack(s) to the LV bus when the received load information is above a first load threshold. The primary DC-DC converters may provide converted power for a steady state load of a LV load, and the secondary DC-DC converter(s) may provide additional converted power for a transient peak demand load of the LV load.

Description

TECHNICAL FIELD The present disclosure relates to a power system for a vehicle. Aspects of the invention relate to a control system for controlling a power system of a vehicle, a power system of a vehicle, a vehicle and a method for operating a control system. BACKGROUND It is known to provide both high voltage and low voltage components in vehicles. Low voltage components may provide important vehicle functions such as assisted steering, braking, and advanced driving assistance systems (ADAS) amongst other functions, and may be typically connected to a low voltage bus such as a 12V bus, optionally with a low voltage battery connected to the low voltage bus. In conventional electric and hybrid vehicles, the low voltage bus and low voltage battery may be powered and / or charged by electrical energy output by a high voltage (such as 400V or 800V) battery, which may be converted to lower voltage by a DC-DC convertor. Low voltage batteries are conventionally used in vehicles to supply these loads. Rising power demands of ADAS systems means that the low voltage battery is constantly being increased in size in order to facilitate the increased power demands. Therefore, there is a need for a power system that is capable of supplying the ADAS power requirements whilst alleviating the dependence on the low voltage battery such that the size of the low voltage battery can be reduced or removed entirely. It is an aim of the present invention to address one or more of the disadvantages associated with the prior art. SUMMARY OF THE INVENTION Aspects and embodiments of the invention provide a control system for controlling a power system of a vehicle, a power system of a vehicle, a vehicle and a method for operating a control system as claimed in the appended claims. According to an aspect of the present invention, there is provided a control system for controlling a power system of a vehicle, the power system comprising at least one high voltage battery pack, at least one primary DC-DC converter, and at least one secondary DC-DC converter, the at least one high voltage battery pack being electrically connected to a low voltage bus via the at least one primary DC-DC converter, and selectively electrically connected via the at least one secondary DC-DC converter, the control system comprising one or more processors collectively configured to: receive load information indicative of a power supply requirement of the low voltage bus; determine, in dependence on the received load information, a control signal for each of the DC-DC convertors, to control the at least one primary DC-DC converter to supply power from the at least one high voltage battery pack to the low voltage bus, and further control the at least one secondary DC-DC converter to supply power from the at least one high voltage battery pack to the low voltage bus when the received load information is above a first load threshold; and output the control signal. In doing so, the high voltage battery is able to continue supplying power to the low voltage bus at increased low voltage load demands of electric vehicle. This enables the low voltage battery to be an appropriate size within the architecture of the EV, or in some cases, the low voltage battery can be removed entirely. Optionally, the first load threshold may be defined by a load voltage at which a load capacity of the at least one primary DC-DC converter is exceeded. The first load threshold may be a current load of 130A per primary DC-DC converter or the first load threshold may be a current load of 260A collectively for the one or more primary DC-DC converters. Optionally, the power system may comprise at least two high voltage battery packs and may comprise at least two primary DC-DC converters. By providing multiple high voltage battery packs, this may allow for redundancy by still being able to supply the low voltage loads from the high voltage battery even if one of the DC-DC converter fails. Optionally, the control signal may comprise instruction for the at least one primary DC-DC converter and the at least one secondary DC-DC converter, such that the at least one primary DC-DC converter and the at least one secondary DC-DC converter are controlled to: draw electrical power from a respective high voltage battery pack; convert the electrical power to a lower voltage; and supply the converted electrical power to the low voltage bus. By enabling the electrical power may be drawn from the primary DC-DC converter, and selectively the secondary DC-DC converter during different load scenarios, a higher efficiency of power supply may be provided by adapting the number of converters according to the load being demanded. Optionally, the at least one secondary DC-DC converter may be connected to at least two high voltage battery packs. The secondary DC-DC converter may be arranged to bridge at least two high voltage battery packs limits the maximum size and weight of the vehicle by not requiring an additional high voltage battery pack. It may also enable greater redundancy as the secondary DC-DC converter may supply from a different high voltage battery pack should there be an issue with a high voltage battery pack. Optionally, the at least one secondary DC-DC converter may have a power rating lower than the at least one primary DC-DC converter. This may enable the secondary DC-DC converter to be optimized to supply power in load scenarios where it is required to provide a small amount of additional power to meet peak demands that cannot be fully supplied by the primary DC-DC converters. Optionally, the at least one primary DC-DC converter may provide a converted power for a steady state load of the low voltage load and the at least one secondary DC-DC converter may provide additional converted power for a transient peak demand load of the low voltage load. As such, the at least one primary DC-DC converter may supply the majority of the low voltage load requirements, in other words, the steady state load requirements and the at least one secondary DC-DC converter may supply the additional low voltage load requirements i.e., when the low voltage load requirements exceed a threshold into a peak demand load range. This may enable the high voltage battery packs to supply the required power during all load conditions. In some instances, this may enable the complete removal of the low voltage battery. Optionally, the steady state load may be a load of the vehicle that does not change overtime during normal operation. The transient peak demand load of the vehicle may be an unexpected, short duration load that occurs in addition to the steady state load of the vehicle. As discussed above, the steady state load may be a current load of 130A per primary DC-DC converter or 260A collectively for the one or more primary DC-DC converters. The transient peak demand may be an additional current load of 100A on top of the steady state load (thus, a total of 360A). Optionally, the control signal may be configured to control the at least one secondary DC-DC converter to supply power from the at least one high voltage battery pack to the low voltage bus for a discrete period of time. The discrete period of time may be 100ms, 200ms or anywhere within the range of 100ms and 200ms. This may enable the secondary DC-DC converter to aid the primary DC-DC converters, by supplying power to the low voltage bus during periods of transient peak load. Optionally, the at least one primary DC-DC converter may be further controlled to: provide converted power to the low voltage bus when the received load information is further indicative of a startup operation of a vehicle. The power system may be arranged such that the primary DC-DC converters provide the power for startup operations from the high voltage battery packs as both the primary converters and the high voltage battery packs may be most applicable for this operation. Optionally, the one or more processors may be collectively configured to output the control signal to one or more electrical switches electrically connected to the at least on secondary DC-DC converter, to thereby isolate or couple the respective primary DC-DC converter or secondary DC-DC converter to the low voltage bus in dependence on the received load information. This may enable the system to be adaptable to changing load scenarios e.g., the primary and secondary DC-DC converters can be coupled or isolated from the low voltage bus such that a customised power delivery system can be utilised. According to another aspect of the invention, there is provided a power system of a vehicle, the power system comprising the control system of any preceding claim, and further comprising: at least one primary DC-DC converter; at least one secondary DC-DC converter; the low voltage bus; and at least one high voltage battery pack; wherein the at least one primary DC-DC converter and the at least one secondary DC-DC converter, each being configured to, in dependence on receipt of the control signal from the control system, draw electrical power from a respective high voltage battery pack.; convert the electrical power to a lower voltage; and supply the converted electrical power to the low voltage bus. In doing so, the high voltage battery is able to continue supplying power to the low voltage bus at increased low voltage load demands of electric vehicle. This enables the low voltage battery to be an appropriate size within the architecture of the EV, or in some cases, the low voltage battery can be removed entirely. Optionally, the power system may further comprise one or more first electrical switches, each electrically connected to a respective primary DC-DC converter and may be configured to isolate or couple the respective primary DC-DC converter from the low voltage bus in response to the control signal from the control system. Optionally, the at least one primary DC-DC convertor and the at least secondary DC-DC converter may comprise communication means configured to transmit information to and receive information from each of the one or more other DC-DC convertors. The at least one primary DC-DC converter and the at least one secondary DC-DC converter may communicate with each other via serial peripheral interface (SPI) communication. The at least one primary DC-DC converter and the at least one secondary DC-DC converter may communicate with the control system via controller area network (CAN) communication. Optionally, the at least one primary DC-DC converter may be communicatively coupled to the at least one secondary DC-DC converter via the communication means and wherein the at least on primary DC-DC converter and the at least one secondary DC-DC converter may be communicatively coupled via the communication means to the control system. In this regard, the at least one primary DC-DC convertors and the at least one secondary DC-DC converters may be configured to transmit one or more of control information, state of charge information, or operating information to other DC-DC convertors and the control system via the communication means. Optionally, the plurality of high voltage battery packs may comprise a single high voltage battery having a plurality of outputs / connections, each output / connection may be connected to a respective DC-DC convertor. The at least one high voltage battery pack may comprise a plurality of high voltage battery packs arranged in series with one another. The plurality of DC-DC convertors may be electrically connected in parallel. The high voltage battery pack may be an 800V battery and the low voltage bus may be a 12V bus. According to another aspect of the invention, there is provided a vehicle comprising the control system of any of any preceding statement or the power system of any preceding statement. According to another aspect of the invention, there is provided a method for operating a control system for controlling a power system of a vehicle, the power system comprising at least one high voltage battery pack, at least one primary DC-DC converter, and at least one secondary DC-DC converter, the at least one high voltage battery pack being electrically connected to a low voltage bus via the at least one primary DC-DC converter, and selectively electrically connected via the at least one secondary DC-DC, the method comprising: receiving load information indicative of a power supply requirement of the low voltage bus; determining, in dependence on the received load information, a control signal for each of the DC-DC convertors, to control the at least one primary DC-DC converter to supply power from the at least one high voltage battery pack, to the low voltage bus, and further control the at least one secondary DC-DC converter to supply power from the at least one high voltage battery pack to the low voltage bus when the received load information is above a first load threshold; and outputting the control signal. According to another aspect of the present invention, there is provided computer readable instructions, which when executed by a processor, are arranged to perform the method of the preceding statement. 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 anyway 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 shows a block diagram illustrating a power system of a vehicle according to the prior art; Figure 2 shows a block diagram illustrating a control system of a vehicle according to an embodiment of the present invention; Figure 3 shows a block diagram illustrating a power system of a vehicle according to an embodiment of the present invention; Figure 4 shows a block diagram illustrating a power system of a vehicle according to an embodiment of the present invention; Figure 5 shows a flow chart showing a method according to an embodiment of the present invention; and Figure 6 shows a vehicle in accordance with an embodiment of the invention. DETAILED DESCRIPTION The present disclosure relates to managementof power supply to a low voltage bus from a high voltage battery or high voltage battery packs. As will be described below, various embodiments include a control system, a power system, a vehicle and a method. An electric vehicle such as a battery electric vehicle (BEV) or a hybrid vehicle such as a mild-hybrid electric vehicle (MHEV) or plug-in-hybrid electric vehicle (PHEV) typically includes at least one high voltage battery pack which is used in part to drive an electric motor to drive the vehicle. The vehicle typically also includes a low voltage battery and / or low voltage bus to power auxiliary functions of the vehicle, such as infotainment system, power steering, automatic braking, or ADAS functions. However, as vehicles develop more advanced ADAS systems, the associated power requirements are also increasing. Typically, these power requirements are supplied by the low voltage battery. Thus, as the power requirements increase, the low voltage battery is being upsized to be able to facilitate the increased power requirements. Eventually, the low voltage battery reaches a size and weight that is not feasible within the vehicle. Therefore, a power system is required there is a need for a power system that is capable of supplying the ADAS power requirements whilst alleviating the dependence on the low voltage battery such that the size of the low voltage battery can be reduced or removed entirely. In some cases, the high voltage battery pack may be used as part of a power system of a vehicle to power the low voltage bus and low voltage loads. In this case, a DC-DC convertor is typically used to step-down the voltage of electrical power output by the high voltage battery pack such that it is suitable for use by the low voltage components. However, since the high voltage battery and the associated DC-DC converter are not designed for supplying low loads challenges such as high voltage battery drain, DC-DC converter reliability and derating arise. To tackle this issue, a new DC-DC converter-based power architecture is proposed which not only reduces size of the low voltage battery but also provides the pulsed power capability. These DC-DC converters are designed for high power density and can support pulse power demand with reduced size and weight compared to conventional systems. The pulsed power architecture may also be obtained by utilising a multi DC-DC converter arrangement, wherein one or more DC-DC converters are specifically designed for pulsed load capability alongside other DC-DC converters which are used to eliminate the low voltage battery and further reduce the assembly footprint. In this context, the ADAS loads, which may also be called low voltage loads, may refer to loads such as headlights, power steering, radio, USB charging, LiDAR, GPS, Ultrasound, IMU, RADAR, camera, computer processing etc. Figure 1 shows an example power system 100 in accordance with the prior art. The power system 100 comprises a low voltage battery 110, load voltage load 120, low voltage bus 130, high voltage battery 140, DC-DC converter 150 and a transient low voltage load 160. However, in some instance the low voltage load 150 may also incorporate the transient low voltage load 160. The DC-DC converter 150 is coupled to the low voltage bus 130 via a switch (S1), when the switch is closed. In conventional vehicles, the low voltage loads 150, 160 are supplied by low voltage battery 110 and a high voltage battery 140 via a DC-DC converter 150, as shown in the Figure 1. With increasing low voltage loads 120 and transient low voltage loads 160, the low voltage battery 110 size increases proportionally. Therefore, it becomes a challenge to support the ever-increasing low voltage load 120 and transient low voltage load 160 requirements. Furthermore, if there is ever a fault with the DC-DC converter 150, then the high voltage battery 140 will not be able to aid in supplying the low voltage loads 120 and the switch S1 will open. Then the power system 100 will be solely reliant on the low voltage battery 110 to supply the low voltage load 120 and transient low voltage load 160, which it may not be capable of. Therefore, there is a need to provide a power system, and associated control system, which can utilise the high voltage battery 140 to supply low voltage loads 120 with increased efficiency. Therefore, there is a need for a power system that is capable of supplying the low voltage load 120 and transient low voltage load 160 whilst alleviating the dependence on the low voltage battery 110 and providing redundancy against failure of the DC-DC converter 150. As such, this would enable the size of the low voltage battery 110 to be reduced or enable the low voltage battery 110 to be removed entirely. A control system 200 in accordance with an embodiment of the present invention is described herein with reference to the accompanying Figure 2 and the power systems 300, 400 in accordance with an embodiment of the present invention is described herein with reference to accompanying Figures 3 and 4. As shown in Figure 6, the control system 200 or the power systems 300, 400 can be installed in a vehicle 600. With reference to Figure 2, there is illustrated a control system 200 for a vehicle 600. The control system 200 comprises one or more controllers 210. The control system 200 is for controlling a power system of a vehicle 600 such as the power system 300 of Figure 3 or the power system 400 of Figure 4, which is described in detail below. The control system 200 as illustrated in Figure 2 comprises one controller 210, although it will be appreciated that this is merely illustrative. The controller 210 comprises processing means 220 and memory means 230. The processing means 220 may be one or more electronic processing device 220 which operably executes computer-readable instructions. The memory means 230 may be one or more memory devices 230. The memory means 230 is electrically coupled to the processing means 220. The memory means 230 is configured to store instructions, and the processing means 220 is configured to access the memory means 230 and execute the instructions stored thereon. The controller 210 comprises an input means 240 and an output means 250. The input means 240 may comprise an electrical input of the controller 210. The output means 250 may comprise an electrical output of the controller 210. The input means 240 is arranged to receive a first signal 260 indicative low voltage bus load information indicative of a power supply requirement of a low voltage bus. The power supply requirement indicates a request from the low voltage bus for electrical power to supply a low voltage load and / or a low voltage bus, and may vary depending on the current operating state of the vehicle 600 e.g. which functions of a vehicle 600 are active and / or based on a charge state of a low voltage battery. For example, the low voltage bus load information may include current and / or voltage information. In some examples, the input means 240 may further receive a signal indicative of state of charge information of one or more of a plurality of high voltage battery packs. The state of charge information may indicate a remaining charge of the high voltage battery pack. The state of charge information may further indicate a maximum state of charge of the high voltage battery pack. In some examples, the input means 240 may further receive capability information indicative of an operational capability of the one or more high voltage battery packs and / or the plurality of DC-DC convertors. For example, the capability information may indicate a maximum output of electrical power that the high voltage battery pack and / or DC-DC convertors are capable of outputting. Further, the capability information may indicate preferred operational conditions of the high voltage battery pack and / or DC-DC convertor, such as a preferred output relative to the maximum output. In this example, the preferred operational conditions may correspond to input and / or output conditions of the high voltage battery pack and / or DC-DC convertor in which the high voltage battery pack and / or DC-DC convertor operate more efficiently than compared to outside of the preferred operational conditions. The processing means 220 is configured to receive information indicative of an operating state of the vehicle 600 and then determine, in dependence on the received operating state of the vehicle 600, a control signal to connect the high voltage to the low voltage bus via one of the first DC-DC converter and the second DC-DC converter. The processing means 220 is then further configured to output the determined control signal to connect the high voltage battery to the low voltage bus. The control system 200 is used for controlling a power system of a vehicle 600. As will be discussed in more detail below, the power system comprises at least one high voltage battery pack, at least one primary DC-DC converter, and at least one secondary DC-DC converter, the at least one high voltage battery pack being electrically connected to a low voltage bus via the at least one primary DC-DC converter, and selectively electrically connected via the at least one secondary DC-DC converter. As such, the control system 200 comprises one or more processors 220 which are collectively configured to receive load information indicative of a power supply requirement of the low voltage bus. Then the one or more processors 220 will determine, in dependence on the received load information, a control signal 260 for each of the DC-DC convertors, to control the at least one primary DC-DC converter to supply power from the at least one high voltage battery pack to the low voltage bus, and further control the at least one secondary DC-DC converter to supply power from the at least one high voltage battery pack to the low voltage bus when the received load information is above a first load threshold. Finally, the one or more processors will be configured to output said control signal. The control signal 260 being outputted to the power system of the vehicle 600. In doing so, the high voltage battery may be able to continue supplying power to the low voltage bus at increased low voltage load demands of electric vehicle 600. This enables the low voltage battery to be an appropriate size within the architecture of the EV, or in some cases, the low voltage battery can be removed entirely. In some examples, the first load threshold may be defined by a load voltage at which a load capacity of the at least one primary DC-DC converter is exceeded. In some examples, the control signal 260 may comprise instructions for the at least one primary DC-DC converter and the at least one secondary DC-DC converter, such that the at least one primary DC-DC converter and the at least one secondary DC-DC converter are controlled to: draw electrical power from a respective high voltage battery pack; convert the electrical power to a lower voltage; and supply the converted electrical power to the low voltage bus. By enabling the electrical power to be drawn from the primary DC-DC converter, and selectively the secondary DC-DC converter during different load scenarios, a higher efficiency of power supply may be provided by adapting the number of converters according to the load being demanded. In some examples, the control signal 260 may be further configured to control at least one secondary DC-DC converter to supply power from the at least one high voltage battery pack to the low voltage bus for a discrete period of time. For example, the discrete period of time may be 200ms. This may enable the at least on secondary DC-DC converter to aid the low voltage bus during peak demand load conditions by providing more electrical power from the at least one high voltage battery pack rather than having to rely upon the low voltage battery. Moreover, the control signal 260 may be further configured to control the at least one primary DC-DC converter to provide converted power to the low voltage bus when the received load information is further indicative of a startup operation of the vehicle 600. The power system may be arranged such that the primary DC-DC converters provide the power for startup operations from the high voltage battery packs as both the primary converters and the high voltage battery packs are most applicable for this operation. Further, in some examples, the one or more processors 220 may be collectively configured to output the control signal 260 to one or more electrical switches electrically connected to the at least one secondary DC-DC converter, to thereby isolate or couple the respective primary DC-DC converter or secondary DC-DC converter to the low voltage bus in dependence on the received load information. This may enable the system to be adaptable to changing load scenarios e.g., the primary and secondary DC-DC converters can be coupled or isolated from the low voltage bus such that a customised power delivery system can be utilised. Figure 3 shows a block diagram illustrating a power system according to an embodiment of the present invention. With reference to Figure 3, there is illustrated a power system 300 for a vehicle 600. The power system 300 of Figure 3 may operate under the control of the control system 200 of Figure 2, and particularly the control signal 270 of Figure 2 may be output to one or more components of the power system 300 of Figure 3. The power system 300 may further comprise a low voltage ground 370 or low voltage return in some examples. The power system 300 of Figure 3 comprises at least one high voltage battery pack 310, a plurality of DC-DC convertors 320, 322, a low voltage load 340, a low voltage battery 350 and a low voltage bus 360. The power system 300 of Figure 3 is shown as comprising a plurality of electrical switches 330, 332, but it should be understood that the plurality of electrical switches 330, 332 are optional in some examples. In this example, the DC-DC converters 320, 322 may be considered as primary DC-DC converters 320, 322. The at least one high voltage battery pack 310 is configured to supply high voltage electrical power through at least one electrical connection to the plurality of DC-DC convertors 320, 322. In some examples, the at least one high voltage battery pack 310 comprises a plurality of high voltage battery packs 311, 312 connected to one another in series and each connected to a respective DC-DC convertor 320, 322. In another example, a single high voltage battery pack 310 is provided, with multiple connections to the plurality of DC-DC convertors 320, 322. For example, the high voltage battery pack 310 may be an 800V battery pack which may comprise of two 400V batteries connected in series, or the high voltage battery pack 310 may in some examples comprise a single 400V battery pack. It should be understood that the term “battery pack” may refer to any suitable type of battery, and may comprise a number of battery cells connected together and packaged as a battery pack. The at least one high voltage battery pack 310 is further configured to receive electrical energy from an electrical power supply, such as an on-board charger (OBC) of a vehicle 600. The plurality of DC-DC convertors 320, 322 are configured to draw electrical power from the at least one high voltage battery pack 310, convert the electrical power to a lower voltage and / or current, and supply the converted electrical power to the low voltage load 340 and / or the low voltage battery 350 via the low voltage bus 360. The plurality of DC-DC convertors 320, 322 may receive information regarding a power requirement of the low voltage bus 360 and may draw power from the high voltage battery pack 310 accordingly. It should be understood that while two DC-DC convertors 320, 322 are shown in Figure 3, any number of DC-DC convertors 320, 322 may be provided. Each of the DC-DC convertors 320, 322 are connected in parallel. Each of the DC-DC convertors 320, 322 are connected to the at least one high voltage battery pack 310 via an independent connection, such that if one of the DC-DC convertors 320, 322 is not operational, the remaining DC-DC convertors 320, 322 are still able to draw electrical power from the at least one high voltage battery pack 310 and supply the electrical power to the low voltage bus 360. In one example, each of the DC-DC convertors 320, 322 are configured to communicate with one another. The DC-DC convertors 320, 322 may in some examples exchange information including operating conditions and / or control information of the DC-DC convertors 320, 322, information relating to connected high voltage battery packs 310, or information received from the control system 200 or the low voltage bus 360 such as power requirement information. The plurality of DC-DC convertors 320, 322 are configured to receive the output signal 270 from the output means 250 of the control system 200 of Figure 2. The plurality of DC-DC convertors 320, 322 are further configured to draw electrical energy from a respective high voltage battery pack 311,312, convert the electrical energy to a lower voltage and / or current, and supply the converted electrical power to the low voltage bus 360. As explained above, based on the control information determined by the control system 200, the DC-DC convertors 320, 322 may operate so as to provide a power load requirement of the low voltage bus 360 split between the DC-DC convertors 320, 322. Thus, the DC-DC convertors 320, 322 and the respective high voltage battery packs 310 may operate more efficiently than in the conventional system. For example, the DC-DC convertors 320, 322 may operate within preferred operational conditions, and thus may operate more efficiently. Further, a state of charge of the high voltage battery packs 310 may be monitored and operation of the respective DC-DC convertors 320, 322 may be controlled to avoid unbalanced depletion of the high voltage battery packs 310, and / orto maintain operation of the high voltage battery packs 310 within preferred state of charge levels. Each of the DC-DC convertors 320, 322 may comprise one or more detection circuitry, detection means or sensors configured to detect at least one operating condition of the respective DC-DC convertor. For example, each DC-DC convertor 320, 322 may comprise a temperature sensor configured to detect a temperature of the DC-DC convertor 320, 322 during operation. In another example, detection circuitry may be provided to detect one or more of an input current being input into the DC-DC convertor 320, 322 (i.e., a current being output by a high voltage battery pack 310); an output current being output by the DC-DC convertor 320, 322; an input voltage being input into the DC-DC convertor 320, 322 (i.e., a voltage being output by a high voltage battery pack 310); or an output voltage being output by the DC-DC convertor 320, 322. Each of the DC-DC convertors 320, 322 may further be configured to provide the operating condition to the control system 200 of Figure 2. As shown in Figure 3, each of the DC-DC convertors 320, 322 may be connected to the low voltage bus 360 via a respective electrical switch 330, 332. In Figure 3, the electrical switches 330, 332 are shown as being open. In the open state, the respective DC-DC convertors 320,322 are electrically isolated from the low voltage bus. The electrical switches 330, 332 are operable to open and close in dependence on receipt of a control signal 270 from the control system 200. When the electrical switches 330, 332 are closed, the respective DC-DC convertors 320, 322 are electrically connected to the low voltage bus 360 and are able to supply electrical energy to the low voltage bus 360. It should be understood that the electrical switches 330, 332 may be omitted in some examples. The low voltage load 340 comprises at least one electronic component which is powered by electrical energy from the low voltage bus 360. In some examples, the low voltage load 340 includes one or more of advanced driving assistance systems (ADAS), power steering functions, or assisted braking functions, but it should be understood that the low voltage load 340 may provide a number of other functions to a vehicle 600 in addition to or alternatively to these examples. In one example, the low voltage load 340 may include components configured to operate on a 12V electrical power supply. The low voltage battery 350 comprises one or more battery cells configured to operate at a voltage and / or current suitable for directly supplying the low voltage bus 360 and the low voltage load 340. In one example, the low voltage battery 350 is a 12V battery. Similar to the high voltage battery pack 310, it should be understood that the low voltage battery 350 may include a single battery or a plurality of batteries electrically connected and packaged together. The low voltage battery 350 may be of any known and suitable battery type. For example, the low voltage battery 350 may include a plurality of battery cells. The low voltage battery 350 may have a capacity sufficient to power the low voltage load 340 for a predetermined time. It should be understood that the power system 300 of Figure 3 may include further components beyond those shown in Figure 3. Further, that the power system 300 of Figure 3 may omit one or more of the components shown in Figure 3 and described above. As noted above, in particular it should be understood that the power system 300 may comprise a different number of high voltage battery packs 310, DC-DC convertors 320, 322 and electrical switches 330, 332 to the number illustrated in Figure 3. In one example, the power system 300 further comprises detection circuitry configured to detect at least one operating condition of the DC-DC convertors 320, 322 and / or the high voltage battery pack 310. As explained above, the DC-DC convertors 320, 322 may themselves comprise means fordetecting the operating conditions of the DC-DC convertors 320, 322. Alternatively or in addition, power system 300 may comprise one or more voltage sensors and / or current sensors or similar provided around the power system 300 of Figure 3 to measure the voltage and / or current at various points in the power system 300. For example, one or more current sensors may be placed between the high voltage battery pack 310 and the DC-DC convertor 320 to measure a current being output by the high voltage battery pack 310 to the DC-DC convertor 320. In another example, a current sensor may be placed between the DC-DC convertor 320 and the electrical switch 330 to measure a current being output by the DC-DC convertor 320. Similarly, one or more voltage sensors may be placed to measure the voltage output by the high voltage battery pack 310 and / or the DC-DC convertor 320, 322. It should be understood that the power system 300 may further comprise various other electronic components which are not shown, including connections to ground, capacitors, inductors and / or resistors. In some examples, the plurality of high voltage battery packs 310 may comprise a single high voltage battery having a plurality of outputs / connections, each output / connection may be connected to a respective DC-DC convertor 320, 322. The at least one high voltage battery pack 310 may comprise a plurality of high voltage battery packs 311,312 arranged in series with one another. The plurality of DC-DC convertors 320, 322 may be electrically connected in parallel. The high voltage battery pack 310 may be an 800V battery and the low voltage bus 360 may be a 12V bus. In some examples, the power system 300 of Figure 3 may configured such that the DC-DC converters 320, 322 are suitably sized to supply the power demands during steady state loads and transient low voltage loads. In this regard, the steady state loads may amount to a load current of 260A, whereas the transient low voltage loads may amount to an additional 100A of load current. Thus, the DC-DC converters 320, 322 may be collectively sized to have the capability to supply at least 360A of load current to the low voltage bus 360. Figure 4 shows a block diagram illustrating a power system according to an embodiment of the present invention. With reference to Figure 4, there is illustrated a power system 400 for a vehicle 600. The power system 400 of Figure 4 may operate under the control of the control system 200 of Figure 2, and particularly the control signal 270 of Figure 2 may be output to one or more components of the power system 400 of Figure 4. The power system 400 may further comprise a low voltage ground or low voltage return in some examples. All of the details discussed in relation to the power system 300 of Figure 3 remain true; the power system 400 of Figure 4 is an extension of the power system 300 of Figure 3. The power system 400 of Figure 4 comprises at least one high voltage battery pack 410, a plurality of DC-DC convertors 420, 422,424, a low voltage load 440, a low voltage battery 450,a low voltage bus 460 and in some examples, a transient low voltage load 480. The power system 400 of Figure 4 is shown as comprising a plurality of electrical switches 430, 432, 434, but it should be understood that the plurality of electrical switches 430, 432, 434 are optional in some examples. In this example, the DC-DC converters 420, 422 may be considered as primary DC-DC converters 420, 424 and the DC-DC converter 424 may be considered a secondary DC-DC converter 424. The power system 400 may further comprise a low voltage ground 470 or low voltage return in some examples. It is worth noting that power system 400 of Figure 4 is an extension of the power system 300 of Figure 3. In this regard, in the power system 400 the secondary DC-DC converter 424 provides the transient low voltage load demand and primary DCDC convertors 420, 422 will only supply the steady state load demand. On the contrary, as discussed previously, in the power system 300 of Figure 3 the DC-DC converter 320, 322 are arranged to supply both the steady state load demand and the transient low voltage demand. Therefore, the power system 400 of Figure 4 may be referred to as a pulsed power compatible architecture as the secondary DC-DC converter 424 may be switched in and out as in needed, in accordance with the load demands. The at least one high voltage battery pack 410 is configured to supply high voltage electrical power through at least one electrical connection to the one or more primary DC-DC convertors 420, 422 and the one or more secondary DC-DC converters 424. In some examples, the at least one high voltage battery pack 410 comprises a plurality of high voltage battery packs 411,412 connected to one another in series and each connected to a respective DC-DC convertor 420, 422, 424. In another example, a single high voltage battery pack 410 is provided, with multiple connections to the plurality of DC-DC convertors 420, 422, 424. For example, the high voltage battery pack 410 may be an 800V battery pack which may comprise of two 400V batteries connected in series, or the high voltage battery pack 410 may in some examples comprise a single 400V battery pack It should be understood that the term “battery pack” may refer to any suitable type of battery, and may comprise a number of battery cells connected together and packaged as a battery pack. The at least one high voltage battery pack 410 is further configured to receive electrical energy from an electrical power supply, such as an on-board charger (OBC) of a vehicle 600. The plurality of DC-DC convertors 420, 422, 424 are configured to draw electrical power from the at least one high voltage battery pack 410, convert the electrical power to a lower voltage and / or current, and supply the converted electrical power to the low voltage load 440 and / or the low voltage battery 450 via the low voltage bus 460. The plurality of DC-DC convertors 420, 422, 424 may receive information regarding a power requirement of the low voltage bus 460 and may draw power from the high voltage battery pack 410 accordingly. It should be understood that while two primary DC-DC convertors 420, 422 and the secondary DC-DC converter 424 are shown in Figure 3, any number of DC-DC convertors 420, 422,424 may be provided. Each of the DC-DC convertors 420, 422, 424 are connected in parallel. Each of the DC-DC convertors 420, 422, 424 are connected to the at least one high voltage battery pack 410 via an independent connection, such that if one of the DC-DC convertors 420, 422, 424 is not operational, the remaining DC-DC convertors 420, 422, 424 may still able to draw electrical power from the at least one high voltage battery pack 410 and supply the electrical power to the low voltage bus 460. In order for the DC-DC converter 420, 422, 424 to supply power to the low voltage bus 460 the associated electrical switch 430, 432, 434 must be closed to couple the DC-DC converter 420, 422, 424 (and in turn the high voltage battery 410) to the low voltage bus 460. It can be said that the at least one primary DC-DC converter 424 and the at least one secondary DC-DC converter 420, 422, are each configured to, in dependence on receipt of the control signal 270 from the control system 200, draw electrical power from a respective high voltage battery pack 410; convert the electrical power to a lower voltage; and supply the converted electrical power to the low voltage bus 460. In some examples, the power system 400 may be configured such that it comprises at least two high voltage battery packs 411,412, and may comprise at least two primary DC-DC converters 420,422. The power system 400 may comprise at least one secondary DC-DC converter 424. The at least one secondary DC-DC converter 424 may have a power rating lower that the at least one primary DC-DC converter 420, 422. The at least one secondary DC-DC converter may be connected to at least two high voltage battery packs 411,412. The secondary DC-DC converter 424, being arranged to bridge at least two high voltage battery packs 411, 412, helps to limit the maximum size and weight of the vehicle 600 by not requiring an additional high voltage battery pack. It also enables greater redundancy as the secondary DC-DC converter 424 can be supplied from a different high voltage battery pack 411,412 should there be an issue with a high voltage battery pack 411, 412. By providing multiple high voltage battery packs 410 and multiple primary DC-DC converters 420, 422, this may allow for redundancy by still being able to supply the low voltage loads 440 from the high voltage battery 410 even if one of the DC-DC converter fails. In some examples, the at least one primary DC-DC converter 420,422 may be used to provide a converted power for a steady state load of the low voltage load 440 and the at least one secondary DC-DC converter 424 may be used to supply additional converted power for a transient peak demand load of the low voltage load 440 e.g. the transient low voltage load 480. In this regard, the at least one secondary DC-DC converter 424 may be be coupled to the low voltage bus 460 via switch 434 when the low voltage load 440 exceeds a predetermined threshold. Therefore, the at least one high voltage battery pack 410 may supply electrical power to the low voltage bus 460 via the one or more primary DC-DC converter 420,422 and the one or more secondary DC-DC converters 424 during transient load conditions, which may be referred to as peak load conditions. The at least one high voltage battery 410 may supply electrical power to the low voltage bus 460 via the at least one primary DC-DC converter 420,422 during steady state load conditions. In other words, the steady state load may be considered a load on the low voltage bus 460 that does not change overtime during normal operation of the vehicle 600. As such, the at least one primary DC-DC converter 420, 422, may supply the majority of the low voltage load 450 requirements, in other words, the steady state load requirements and the at least one secondary DC-DC converter 424 may supply the additional low voltage load 450 requirements i.e., when the low voltage load requirements exceed a threshold into a peak demand load range e.g. the transient low voltage load requirements 450. This enables the high voltage battery packs 410 to supply the required power during all load conditions. In some instances, this may enable the complete removal of the low voltage battery. In otherwords, the transient peak demand load may be considered as an unexpected, short duration load on the low voltage bus 460 of the vehicle 600 which is in addition to the steady state load. In some examples, the at least on primary DC-DC converter 420, 422, and the at least one secondary DC-DC converter 424 may comprise communication means which may be configured to transmit information to and receive information from each of the one or more other DC-DC converters. In this regard, the at least one primary DC-DC converter 420, 422, may be communicatively coupled to the at least one secondary DC-DC converter 424 via the communication means. Further, the at least one primary DC-DC converter 420, 422 and the at least one secondary DC-DC converter 424 may be communicatively coupled via the communication means to the control system 200. In this regard, the at least one primary DC-DC converter 420, 422 and the at least one secondary DC-DC converter 424 may communicate with each other via serial peripheral interface (SPI) communication or any other suitable communication means. The at least one primary DC-DC converter 420, 422 and the at least one secondary DC-DC converter 424 may communicate with the control system 200 via controller area network (CAN) communication or any other suitable communication means. In some examples, the plurality of high voltage battery packs 410 may comprise a single high voltage battery having a plurality of outputs / connections, each output / connection may be connected to a respective DC-DC convertor 420, 422, 424. The at least one high voltage battery pack 410 may comprise a plurality of high voltage battery packs 411, 412 arranged in series with one another. The plurality of DC-DC convertors 420, 422, 424 may be electrically connected in parallel. The high voltage battery pack 410 may be an 800V battery and the low voltage bus 460 may be a 12V bus. Figure 5 shows a flow chart showing a method 500 according to an embodiment of the present invention. The method 500 of Figure 5 may be implemented by the control system 200 of Figure 2 and / or the power system 300 or 400 of Figure 3 or 4. The method 500 of Figure 5 may be stored on computer readable storage medium, or as computer readable instructions. The method 500 of Figure 5 includes, at 510, receiving load information indicative of a power supply requirement of the low voltage bus 360, 460. As discussed above, the received information indicative of a power supply requirement of the low voltage bus 360, 460, which may optionally comprise information indicating the how many components of the vehicle 600 are currently active and drawing current. In some instances, received information indicative of a power supply requirement may be indicative of an operating state of the indicate that the vehicle 600 is in standby mode or in normal operation. In other words, the received information indicative of an operating state of the vehicle 600 e.g., the vehicle 600 is parked and not in use (standby mode) or that one or more components of the vehicle 600 are receiving electrical power (normal operation mode). The received information may also comprise voltage and / or current information of a low voltage load 340, 440 (and the transient low voltage load 350, 450) required by the low voltage bus 360, 460. The method 500 of Figure 5 further includes, at 520, determining, in dependence on the received load information, a control signal for each of the DC-DC convertors 320, 322, 420, 422, 424, to control the at least one primary DC-DC converter 320, 322, 420, 422 to supply power from the at least one high voltage battery 310, 410 pack to the low voltage bus 360, 460, and further control the at least one secondary DC-DC converter 424 to supply power from the at least one high voltage battery pack 410 to the low voltage bus 460 when the received load information is above a first load threshold. In this regard, the primary DC-DC converter 420,422 may be designed fora maximum of 130A of steady state load current each, thus, a total of 260A of steady state load between the primary DC-DC converters 420, 422. In the event, there is a sudden transient demand above the 260A of steady state load then the secondary DC-DC converter 424 will support the primary DC-DC converters 420, 422 with the additional current requirements. The sudden transient demand, which may be referred to as transient load conditions, may be in the region of 100A of additional current demand. This current demand may come from the steering assist unit, the breaking assist unit etc. Therefore, the first load threshold may be considered as 260A or 130A per primary DC-DC converter 420, 422. Optionally, the at least one secondary DC-DC converter 424 may supply power from the high voltage battery 410 to the low voltage bus 460 for a discrete period of time to enable the system to adequately supply increased transient peak load demands. The discrete period of time may be a time period between 100ms and 200ms. These transient peak load demands may be sustained for a short period of time, hence the at least one secondary DC-DC converter 424 may be controlled to supply power for a discrete period of time. Once, the load demand on the low voltage bus 460 falls back below a first threshold value, the low voltage bus 460 will be supplied power solely from the at least one primary DC-DC converter 420, 422. However, should there be a fault with one or more of the at least one primary DC-DC converters 420, 422, the at least one secondary DC-DC converter 424 may be controlled to supply power to the low voltage bus 460 form the high voltage battery 410 under all load scenarios. In some examples, the high voltage battery 310, 410 is able to continue supplying power to the low voltage bus 360, 460 at increased low voltage load demands 340, 440 of electric vehicle 600. This enables the low voltage battery to be an appropriate size within the architecture of the EV, or in some cases, the low voltage battery can be removed entirely. The method 500 comprises, at 530, outputting the control signal. In this sense, the control signal is the control signal determined at 520. Outputting the determined control signal may cause the at least one primary DC-DC converter 320, 322, 420, 422 and the at least one secondary DC-DC converter 424, each being configured to, in dependence on receipt of the control signal from the control system to draw electrical power from a respective high voltage battery pack 310,410, convert the electrical power to a lower voltage; and supply the converted electrical power to the low voltage bus 360, 460. Figure 6 shows a vehicle 600 in accordance with an embodiment of the invention. The vehicle 600 may include the control system 200 of Figure 2 and / or the power system 300 or 400 of Figure 3 or 4. As described above, the vehicle 600 may be an electric vehicle such as a battery electric vehicle (BEV) or a hybrid vehicle such as a mild-hybrid electric vehicle (MHEV) or plug-in-hybrid electric vehicle (PHEV). Vehicle 600 may also be an EGO vehicle, i.e., a vehicle that is equipped with autonomous or semi-autonomous driving technology and is capable of sensing and navigating its environment without direct input from a human driver. It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the present application.

Claims

1. A control system for controlling a power system of a vehicle, the power system comprising at least one high voltage battery pack, at least one primary DC-DC converter, and at least one secondary DC-DC converter, the at least one high voltage battery pack being electrically connected to a low voltage bus via the at least one primary DC-DC converter, and selectively electrically connected via the at least one secondary DC-DC converter, the control system comprising one or more processors collectively configured to:receive load information indicative of a power supply requirement of the low voltage bus;determine, in dependence on the received load information, a control signal for each of the DC-DC convertors, to control the at least one primary DC-DC converter to supply power from the at least one high voltage battery pack to the low voltage bus, and further control the at least one secondary DC-DC converter to supply power from the at least one high voltage battery pack to the low voltage bus when the received load information is above a first load threshold; and output the control signal.

2. The control system of claim 1, wherein the power system comprises at least two high voltage battery packs and at least two primary DC-DC converters.

3. The control system of any preceding claims, wherein the control signal comprises instructions for the at least one primary DC-DC converter and the at least one secondary DC-DC converter, such that the at least one primary DC-DC converter and the at least one secondary DC-DC converter are controlled to:draw electrical power from a respective high voltage battery pack;convert the electrical power to a lower voltage; andsupply the converted electrical power to the low voltage bus.

4. The control system of any preceding claim, wherein the at least one secondary DC-DC converter is connected to at least two high voltage battery packs.

5. The control system of any preceding claim, wherein the at least one secondary DC-DC converter has a power rating lower than the at least one primary DC-DC converter.

6. The control system of any preceding claim, wherein the at least one primary DC-DC converter provides a converted power for a steady state load of the low voltage load and the at least one secondary DC-DC converter provides additional converted power for a transient peak demand load of the low voltage load.

7. The control system of any preceding claims, wherein the control signal is configured to control the at least one secondary DC-DC converter to supply power from the at least one high voltage battery pack to the low voltage bus for a discrete period of time.

8. The control system of claim 6, wherein the at least one primary DC-DC converter are further controlled to: provide converted power to the low voltage bus when the received load information is further indicative of a startup operation of a vehicle.

9. The control system of any preceding claims, wherein the one or more processors are collectively configured to output the control signal to one or more electrical switches electrically connected to the at least one secondary DC-DC converter, to thereby isolate or couple the respective primary DC-DC converter or secondary DC-DC converter to the low voltage bus in dependence on the received load information.

10. A power system of a vehicle, the power system comprising the control system of any preceding claim, and further comprising:at least one primary DC-DC converter;at least one secondary DC-DC converter;the low voltage bus; andat least one high voltage battery pack;wherein the at least one primary DC-DC converter and the at least one secondary DC-DC converter, each being configured to, in dependence on receipt of the control signal from the control system, draw electrical power from a respective high voltage battery pack; convert the electrical power to a lower voltage; and supply the converted electrical power to the low voltage bus.

11. The power system of claim 8, comprising one or more first electrical switches, each electrically connected to a respective primary DC-DC converter and configured to isolate or couple the respective primary DC-DC converter from the low voltage bus in response to the control signal from the control system.

12. The power system of any of claims 8 to 10, wherein the at least one primary DC-DC convertor and the at least secondary DC-DC converter comprise communication means configured to transmit information to and receive information from each of the one or more other DC-DC convertors.

13. The power system of claim 11, wherein the at least one primary DC-DC converter is communicatively coupled to the at least one secondary DC-DC converter via the communication means and wherein the at least on primary DC-DC converter and the at least one secondary DC-DC converter are communicatively coupled via the communication means to the control system.

14. A vehicle comprising the control system of any of claims 1 to 9 or the power system of any of claims 10 to 13.

15. A method for operating a control system for controlling a power system of a vehicle, the power system comprising at least one high voltage battery pack, at least one primary DC-DC converter, and at least one secondary DC-DC converter, the at least one high voltage battery pack being electrically connected to a low voltage bus via the at least one primary DC-DC converter, and selectively electrically connected via the at least one secondary DC-DC, the method comprising: receiving load information indicative of a power supply requirement of the low voltage bus; determining, in dependence on the received load information, a control signal for each of theDC-DC convertors, to control the at least one primary DC-DC converter to supply power from the at least one high voltage battery pack to the low voltage bus, and further control the at least one secondary DC-DC converter to supply power from the at least one high voltage battery pack to the low voltage bus when the received load information is above a first load threshold; and outputting the control signal.Application No: GB2407008.8Examiner: Contract Unit ExaminerClaims searched: 1-15Date of search: 8 April 2025Patents Act 1977: Search Report under Section 17Documents considered to be relevant:Category Relevant to claims Identity of document and passage or figure of particular relevance X 1-15 US 2021 / 0006066 Al (TAKEMOTO) Paragraphs [0003], [0024]-[0030], [0034]-[0036], [0038], [0042], [0043], [0046]; figures 1, 2. X 1-15 US 2015 / 258947 Al (HARKINS) Paragraphs [0023], [0029]-[0054], [0061], [0066]-[0068]; figures 1-4, 6. x,& 1-15 JP 5387651 B2 (DENSO CORP.) See whole document. x,& 1-15 US 2013 / 0099559 Al (MACHI et al) Paragraphs [0032]-[0035], [0043]-[0095]; figures 1-3E. X 1-15 CN 117162781 A (DONGFENG AUTOMOBILE CO. LTD.) Paragraphs [0042]-[0075]; figures 1,2. v A 1-15 CN 116915038 A (SHINRY TECH. CO. LTD.) Paragraphs [0068]-[0186]; figures 1-5. A - US 2019 / 0291601 Al (VANERHAV etal) Paragraphs [0033]-[0036], [0042]-[0047]; figures 1-3.Categories:X Document indicating lack of novelty or inventive step A Document indicating technological background and / or state of the art. Y Document indicating lack of inventive step if p Document published on or after the declared priority date but combined with one or more other documents of same category. before the filing date of this invention. & Member of the same patent family E Patent document published on or after, but with priority date earlier than, the filing date of this application.Field of Search:International Classification:Subclass Subgroup Valid From B60L 0001 / 00 01 / 01 / 2006 B60L 0050 / 60 01 / 01 / 2019 B60R 0016 / 03 01 / 01 / 2006

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