GB2598374A

GB2598374A - Electrical vehicle circuitry

Info

Publication number: GB2598374A
Application number: GB2013572.9A
Authority: GB
Inventors: Fai Yu Tung; Nicholls Stephen; Devenport Richard
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2020-08-28
Filing date: 2020-08-28
Publication date: 2022-03-02
Also published as: DE102021122059A1; GB2600526A; GB202013572D0; GB2600526B; GB202112274D0

Abstract

An electrical power circuit provides a pre-charge current to a traction bus of a vehicle (e.g. EV, HEV) and includes: a terminal for electrical connection to a traction battery 20; a DC-DC converter 22 coupled to the terminal; and a high voltage (HV) traction bus 27 for providing electrical power to one or more traction motors 28. The converter receives a first voltage (e.g. from a traction battery or an onboard charger (OBC)) and provides a second voltage to a high voltage auxiliary power bus. The converter is coupled to the traction bus via the auxiliary power bus. In response to an indication that power is to be applied to the traction bus, the converter provides the second voltage to the auxiliary power bus to provide a pre-charge current to the traction bus. The voltage on the traction bus is balanced before the traction bus is connected to the battery. A first switch 21 may connect the terminal and the traction bus in dependence on a parameter associated with the traction bus, e.g. when the voltage of the traction bus exceeds a threshold voltage. A battery control circuit may selectively interconnect first and second plurality of cells of the battery: in series, to provide a first battery voltage at a battery output; or in parallel, to provide a second battery voltage at the battery output. The second battery voltage may be provided by connecting the first plurality of cells to, and isolating the second plurality of cells from, the battery output.

Description

ELECTRICAL VEHICLE CIRCUITRY

TECHNICAL FIELD

The present disclosure relates to an electrical power circuit for a vehicle. Aspects relate to an electrical power circuit, to a battery assembly, to a control system, to a vehicle, to a method, and to computer software.

BACKGROUND

Electric vehicles and hybrid electric vehicles comprise traction motors, and traction batteries for supplying electrical energy to the traction motors.

High voltage circuits used to connect traction motors to the traction batteries are often provided with a pre-charge circuit comprising a resistor and switch, such as a relay, arranged in parallel with a primary switch, such as a contactor, connecting the high voltage circuit to a source of electrical power. The pre-charge circuit allows the high voltage circuit to be voltage balanced prior to closing the primary switch, avoiding a sudden current spike when connecting the high voltage circuit to the source of electrical power which could otherwise cause significant stress on the primary switch.

The pre-charge circuit components may typically be high cost with fixed functionality and these components utilize packaging space and may create thermal challenges. Furthermore, the pre-charge circuit may have limited adjustability to pre-charge timing and voltage range.

It is an aim of embodiments 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, an electrical power system for a vehicle, a vehicle, a method, and computer software as claimed in the appended claims.

According to an aspect of the present invention there is provided an electrical power circuit for a vehicle, the electrical power circuit comprising a terminal for electrical connection to a traction battery, a DCDC converter coupled to the terminal, the DCDC convertor arranged to receive a first voltage and to provide a second voltage to a high voltage auxiliary power bus, a HV traction bus for providing electrical power to one or more traction motors, and wherein the DCDC converter is coupled to the high voltage traction bus via the auxiliary power bus, the DCDC converter arranged, in response to an indication that power is to be applied to the high voltage traction bus, to provide the second voltage to the high voltage auxiliary power bus in order to provide a pre-charge current to the high voltage traction bus.

According to an embodiment, the electrical power circuit may further comprise first switching means coupled between the terminal and the high voltage traction bus, wherein the first switching means may be arranged, in dependence on a parameter associated with the high voltage traction bus, to electrically connect the terminal to the high voltage traction bus.

Optionally, the parameter may comprise one of: temperature, a magnitude of the pre-charge current, a time for which the pre-charge current has been supplied to the high voltage traction bus, and a voltage of the high voltage traction bus.

According to some embodiments, the parameter associated with the high voltage traction bus may comprise the voltage of the high voltage traction bus and the first switching means may be arranged, in dependence on the voltage of the high voltage traction bus being greater than a threshold voltage, to electrically connect the terminal to the high voltage traction bus.

According to some embodiments, the electrical power circuit may comprise second switching means coupled in series with a resistive load, the second switching means and the resistive load coupled between the terminal and the DCDC converter, and third switching means coupled between the terminal and the DCDC converter in parallel with the second switching means and the resistive load.

Optionally, the first voltage may comprise a nominal voltage in the range of one of 300V to 500V and 600V to 1000V and the second voltage may comprise a nominal voltage in the range of 300V to 500V.

According to some embodiments, the electrical power circuit may comprise an onboard charger coupled to the DCDC convertor, the onboard charger may be arranged to receive AC power and to provide the first voltage to the DCDC convertor, the DCDC converter may be arranged to convert the first voltage provided by the onboard charger to provide the pre-charge current to the high voltage traction bus.

Optionally, the first voltage may be provided by a traction battery coupled to the terminal, the DCDC converter may be arranged to convert the first voltage provided by the traction battery to provide the pre-charge current to the high voltage traction bus.

According to another aspect of the invention, there is provided a battery assembly comprising a traction battery and the electrical power circuit as described above, wherein the traction battery is coupled to the terminal.

Optionally, the traction battery may comprise a first plurality of cells, a second plurality of cells, and a battery control circuit to selectively interconnect the first and second plurality of cells in series to provide a first battery voltage at a battery oupoiut in a first mode of operation and to selectively interconnect the first and second plurality of cells in parallel to provide a second battery voltage at the battery output in a second mode of operation.

Optionally, the battery control circuit may be further configured to connect the first plurality of cells to the battery output and isolate the second plurality of cells from the battery output to provide the second battery voltage.

According to yet another aspect of the invention, there is provided a control system for controlling an electrical power circuit of a vehicle, the control system comprising input means to receive a first signal indicating that power is to be applied to a high voltage traction bus of the vehicle, output means for outputting a control signal for controlling a DCDC convertor of the electrical power circuit, and processing means arranged, in dependence on the first signal indicating that power is to be applied to the high voltage traction bus, to control the output means to output the control signal to cause the DCDC converter to supply a first voltage to a high voltage auxiliary bus in order to supply a pre-charge current to a high voltage traction bus of the vehicle.

According to an embodiment, there is provided the control system as described above, wherein said processing means, said input means for receiving the first signal indicating that power is to be applied to the high voltage traction bus of the vehicle and said output means for outputting the control signal for controlling the DCDC convertor of the electrical power circuit comprise one or more electronic processors having an electrical input for receiving said first signal and an electrical output for transmitting said control signal, the control system further comprising an electronic memory device electrically coupled to the one or more electronic processors and having instructions thereon.

Optionally, the input means may be arranged to receive a second signal indicative of a parameter associated with the high voltage traction bus of the vehicle and the processing means may be arranged to determine a parameter of the high voltage traction bus in dependence on the second signal and, in dependence on the determined parameter of the high voltage traction bus, control the output means to output a control signal to cause a first switching means coupled between the high voltage traction bus and a traction battery to electrically couple the high voltage traction bus to the traction battery.

Optionally, the parameter of the high voltage traction bus may be based on at least one of: temperature, a magnitude of the pre-charge current, a time for which the pre-charge current has been supplied to the high voltage traction bus, and a voltage of the high voltage traction bus.

According to some embodiments, the parameter of the high voltage traction bus may comprise the voltage of the high voltage traction bus and the processing means may be arranged to control the output means to output a control signal to cause a first switching means coupled between the high voltage traction bus and a traction battery to electrically couple the high voltage traction bus to the traction battery in response to the voltage of the high voltage traction bus being greater than a threshold voltage According to some embodiments, the control system may further comprise parameter sensing means arranged to monitor the parameter of the high voltage traction bus and output the second signal indicative of the parameter of the high voltage traction bus.

According to some embodiments, the control system may be arranged to control the output means to output a control signal to cause a second switching means coupled between a traction battery and the DCDC convertor to electrically couple the DCDC converter to the traction battery, the second switching means connected in series with a resistive load, and control the output means to output a control signal to cause a third switching means coupled in parallel with the second switching means and the resistive load, between the traction battery and the DCDC convertor to close.

According to some embodiments, the control system may be arranged, subsequent to the third switching means being caused to close, to control the output means to output a control signal to cause the second switching means to open.

Optionally, the input means may be configured to receive a signal indicating that an onboard charger coupled to the DCDC convertor is receiving AC power and the processing means may be arranged, in dependence on the signal indicating that an onboard charger is receiving AC power to control the output means to output a control signal to cause the DCDC convertor to convert a first voltage provided by the onboard charger to provide the pre-charge current.

According to some embodiments, the control system may be coupled to a traction battery comprising a first plurality of cells, a second plurality of cells and a battery circuit operable in response to a control signal to selectively interconnect the first and second plurality of cells in series to provide a first battery voltage at a battery output in a first mode or operation, and to selectively interconnect the first and second plurality of cells in parallel to provide a second battery voltage at the battery output in a second mode of operation and the output means may be arranged to provide the control signal to the battery circuit.

According to yet another aspect of the invention, there is provided a vehicle comphsing the electrical power circuit, the battery assembly, or the control system as described above.

According to yet another aspect of the invention, there is provided a method of controlling an electrical power circuit for a vehicle, the method comprising determining that power is to be applied to a high voltage traction bus of the vehicle, and in response to determining that power is to be applied to the HV traction bus causing electrical power to be applied to a DCDC convertor, the DCDC convertor configured to supply a first voltage to a high voltage auxiliary bus in order to provide a pre-charge current to the high voltage traction bus.

According to some embodiments, the method may further comprise monitoring a parameter of the high voltage traction bus and connecting the high voltage traction bus to a traction battery in dependence on the monitored parameter.

Optionally, the parameter may be based on at least one of: a temperature, a magnitude of the pre-charge current, a time value associated with the high voltage traction bus, and a voltage of the high voltage traction bus.

According to some embodiments, the parameter of the high voltage traction bus may comprise a voltage of the HV traction bus and wherein connecting the high voltage traction bus to a traction battery in dependence on the monitored parameter may comprise connecting the high voltage traction bus to a traction battery in dependence on the voltage of the high voltage traction bus being greater than a threshold voltage.

According to some embodiments, the method may comprise, subsequent to connecting the high voltage traction bus to the traction battery, controlling the DCDC convertor to stop providing the pre-charge current.

Optionally, causing electrical power to be applied to the DCDC convertor may comprise supplying electrical power from the traction battery.

Optionally, causing the electrical power to be applied to the DCDC convertor may comprise supplying electrical power from an external AC supply via an onboard charger coupled to the DCDC convertor.

According to yet another aspect of the invention, there is provided Computer software which, when executed by a computer, is arranged to perform any method described herein. Optionally, the computer software is stored on a computer readable medium The computer software may be tangibly stored on a computer readable medium.

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 odginally 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 illustrates a vehicle in accordance with an embodiment of the invention; Figure 2 illustrates an example of a traction battery, a traction motor and a control system in accordance with embodiments; Figure 3 illustrates an electrical power circuit connected to a traction battery in accordance with embodiments; Figure 4A illustrates an example of a control system comprising a controller in accordance with embodiments; Figure 4B illustrates an example of a non-transitory computer readable medium storing instructions in accordance with embodiments; Figure 5 illustrates an example of a method in accordance with embodiments; Figure 6 illustrates an example of a further method in accordance with embodiments.

DETAILED DESCRIPTION

Examples disclosed herein may provide a circuit and method for pre-charging a high voltage traction bus of an electrical vehicle without the use of a secondary switch and resistive element arranged in parallel with a primary switch for electrically connecting the high voltage traction bus to a traction battery. In embodiments, a DCDC convertor adapted to provide a voltage to a high voltage auxiliary bus may be further coupled to the high voltage traction bus and adapted to provide a pre-charge current.

Figure 1 illustrates an example of a vehicle 10 in which embodiments of the invention can be implemented. In some, but not necessarily all examples, the vehicle 10 is a passenger vehicle, also referred to as a passenger car or as an automobile. In other examples, embodiments of the invention can be implemented for other applications, such as industrial vehicles.

The vehicle 10 may be an electric vehicle (EV) or a hybrid electric vehicle (HEV). If the vehicle 10 is an HEV, the vehicle 10 may be a plug-in HEV or a mild NEV. If the vehicle 10 is a plug-in HEV, the vehicle 10 may be a series HEV or a parallel HEV. In a parallel HEV, a traction motor and an internal combustion engine are operable in parallel to simultaneously provide tractive torque. In a series HEV, the internal combustion engine generates electricity and the traction motor exclusively provides tractive torque.

Figure 2 illustrates an electrical power system 200 comprising a traction battery 20 (battery' herein), a DCDC convertor 22 and a control system 26 for the EV or HEV 10, which may be supplied together or separately. Figure 2 also illustrates a traction motor 28 which could optionally be part of the system 200.

The battery 20 may be a high voltage battery, particularly if the vehicle 10 is an EV or a plug-in HEV. High voltage traction batteries provide nominal voltages in the hundreds of volts, as opposed to traction batteries for mild HEVs which provide nominal voltages in the tens of volts. The battery 20 may have a voltage and capacity to support electric only driving for sustained distances requiring continuous battery power.

The nominal voltage of the battery 20 may be in the hundreds of volts. In some examples, the nominal voltages of the battery 20 is from the range 250-1000 volts, or more specifically between 270V to 470V, or between 600V to 1000V. In specific examples, the nominal voltage may be 400 volts or 800volts to one significant figure. The nominal voltage is defined as the voltage between a positive terminal 25 of the battery and a negative terminal of the battery.

The battery 20 may have a capacity of several kilowatt-hours, to maximise range. The capacity may be in the tens of kilowatt-hours, or even over a hundred kilowatt-hours.

The battery 20 comprises a positive terminal 25 and a negative terminal. The terminals may be configured for connection to switching means to selectively connect the battery 20 to a high voltage traction bus 27, as illustrated by switch 21 coupled between positive terminal 25 of the battery 20 and the HV traction bus 27. The high voltage traction bus 27 may be configured to supply energy from the battery 20 to the traction motor 28.

The terminals of the battery 20 are also configured for connection to DCDC convertor 22. The DCDC convertor 22 is configured to receive a DC voltage supplied by battery 20 and provide one or more regulated DC voltage outputs, such as to a high voltage auxiliary bus 24.

The DCDC convertor 22 further comprises an output 23 coupled to high voltage traction bus 27. The DCDC convertor 22 is controllable to provide a pre-charge current to the high voltage traction bus 27 via the output 23 to balance the voltage on the HV traction bus 27 prior to closing switch 21 to connect the HV traction bus 27 to the battery.

The control system 26 may be operable to receive an indication that power is to be coupled to the HV traction bus 27, i.e. the HV traction bus 27 is to be connected to the battery 20 by closing switch 21. In response to receiving the indication that power is to be coupled to the HV traction bus 27, the control system 26 may cause a control message to be transmitted to the DCDC convertor 22 to control the DCDC convertor to provide the pre-charge current at the output 23. The pre-charge current may be provided by selectively coupling the output 23 to the high voltage auxiliary bus 24.

The control system 26 may be operable to monitor a parameter associated with the HV traction bus 27 and to provide a control signal to control the state of switch 21 based on the monitored parameter. For example, the control circuit 26 may be arranged to receive a signal indicating a parameter value and control the state of the switch 21 based on the received indication.

The parameter monitored by the control system 26 may be a temperature, a voltage of the HV traction bus 27, a magnitude of the pre-charge current provided to the HV traction bus 27 by the DC DC convertor 22, and/or a time for which the pre-charge current has been supplied to the HV traction bus 27 by the DCDC convertor 22. For example, the control system 26 may compare a monitored voltage of the HV traction bus 27 with a threshold voltage and in response to determining that the monitored voltage is greater than the threshold voltage control switch 21 to couple the battery to the HV traction bus 27. In other embodiments, the control system 26 may monitor the magnitude of the pre-charge current provided by the DCDC convertor 22 which may be expected to decrease as the voltage of the HV traction bus 27 increases allowing the control system 26 to determine when the HV traction bus has been charged to a sufficient voltage or the control system 26 may control the DCDC convertor 22 to apply the pre-charge voltage for a predetermined amount of time before causing the switch 21 to close and connect the HV traction bus 27 to the battery 20.

In embodiments, control system 26 may receive an indication of the voltage of the HV traction bus 27 and also an indication of the voltage provided by the traction battery 20 at terminal 25. The control system 26 may compare these voltages and provide a control message to cause the switch 21 to close based on a determination that the voltages are within a threshold voltage Although one battery 20 is shown, the vehicle 10 could comprise additional traction batteries.

Although one traction motor 28 is shown, the vehicle 10 could comprise additional traction motors, for the same or different wheels of the vehicle 10.

In some examples, DCDC convertor 22 may be selectively connectable to the battery 20 under control of the control system 26. For example, a second switching means coupled in series with a resistive load may be provided between positive terminal 25 of the battery 20 and the DCDC convertor 22 along with a third switching means coupled in parallel with the second switching means and the resistive load. The second and third switching means may be controllable by the control system 26.

When it is determined that power should be applied to the DCDC convertor 22, for example at the beginning of a drive cycle when a user wishes to operate the vehicle 10, the control system 26 may provide a control signal instructing the second switching means to close, connecting the DCDC convertor 22 to the positive battery terminal 25 via the resistive load to pre-charge the DC DC convertor circuitry. Once it is determined that the DCDC convertor circuitry is sufficiently pre-charged, the control system 26 may provide a control signal instructing the third switch to close providing a direct connection for electrical power to be provided between the terminal 25 and the DCDC convertor 22. Such a determination may be based on a particular time having elapsed, or on a signal indicating a voltage of the DCDC convertor circuitry.

The DCDC convertor 22 may further comprise charging circuitry such as an on-board charger (OBC), for connecting a charging port (not shown) and/or a generator to the battery 20. The on-board charger may be configured to receive electrical power from an external source, such as an AC power supply, and to provide a DC current that can be used to charge the battery 20 and also to power the DCDC convertor 22, along with any electrical buses or devices that has power supplied by the DCDC convertor 22. In some examples, control system 26 may anticipate that power is to be provided to the HV traction bus 27 and control the DCDC convertor 22 to use the DC voltage provided by the on-board charger to supply the pre-charge current via output 23 to the HV traction bus 27 using electrical energy supplied by the external power source.

Figure 3 shows an electrical power circuit 300 connected to a traction battery 20 to form a battery assembly 350 for a vehicle according to examples disclosed herein. The circuit 300 in this example is labelled as a Battery Energy Module (BEM). Within the BEM 300 there is a Modular Electrical Electronic Architecture MEEA module 320 which houses, in this example, a first high voltage DCDC converter 312a, a second DCDC converter 312b, and an OBC 316.

The circuit 300 comprises a charging input 302 labelled "400V/800V HV DC Charger' for receiving electrical energy, which is connected to the DCDC converters 312a, 312b, to the OBC 316, and to the external battery pack 20 via the battery connection terminal 25. The connection from the charging input 302 to the battery pack 20 is to supply electrical energy from the charging input 302 for charging the traction battery 20.

The battery connection terminal 25 electrically connects the traction battery 20 to the DCDC converters 312a, 312b and the OBC 316, and can receive electrical energy from the traction battery 20 to power one or more traction motors 28 of the vehicle at the second voltage (in this example, output at 400V to a HV DC Front Traction motor and a HV DC Rear Traction motor 28 are shown). For example, electrical energy from the charging input 302 may be supplied at 800V or 400V to charge the traction battery 20, and a traction motor 28 may be powered by the traction battery 20 at 400V. One DCDC converter 312a is shown as configured to convert either 800V or 400V input to 400V output (though other high voltage outputs may be provided in different examples). Another DCDC converter 312b is shown as configured to convert either 800V or 400V input to 12V output (though other low voltage outputs may be provided in different examples). Other examples may comprise one, three, or more than three DCDC converters.

The HV DCDC converter 312a is connected to a HV output 310a labelled in this example as "400V 15kW Auxiliary Units" (the output 310a itself comprises two output channels, a first to a HV DC Heater and a second to a HC DC Chiller). The HV DCDC convertor 312a is further connected to the HV traction bus 27 via output 23 to provide the pre-charge current to the HV traction bus 27.

The LV DCDC converter 312b is connected to a LV output 310b labelled in this example as "4kW LV DCDC". The outputs 312a, 312b each respectively connect to an electrical bus of the vehicle for providing electrical power to electrical units of the vehicle at the indicated output voltages (two HV outputs 310a and one LV output 310b in this example). The DCDC converters 312a, 312b are each respectively configured to receive electrical energy from the charging input 302, and provide electrical energy at the output voltage(s) to the outputs 310a, 310b, and 23, whilst the traction battery 306 is charged at the first voltage.

In this example, the first output 310a may provide an output at 400V, which may be the same voltage, 400V, as that provided at the input 302 in some cases.

The DCDC converters 312a, 312b in this example are also configured to receive electrical energy from an AC charging input 314 (labelled "HV AC Charger"), and convert the received AC current to provide electrical energy to the battery connection terminal 25 at the first voltage for charging the traction battery 20. The onboard charger 316 is coupled to the DCDC converters 312a, 312b. The onboard charger 316 is configured to receive AC current at the AC charging input terminal 314, and provide a DC current to the DCDC converters 312a, 312b. In this example, the OBC 316 is shown as configured to accept 800V or 400V input voltage. In this example, the AC charging input 314 forms an external connection, for example for connection to an AC charge supply, and is connected to the OBC 316 which receives AC input power and provides DC power to the DCDC converters 312a, 312b. Also shown in this example are service test points 324 configured to allow electrical access for connecting testing of the BEM.

The traction battery 20 in this example is shown electrically connected to the battery connection terminal 25 and allows for connection of the battery pack 20 to the power circuit 200. The traction battery 20 in this example is comprises a first plurality of cells 322a, a second plurality of cells 322b, and a battery control circuit (not shown) to selectively interconnect the first and second plurality of cells 322a, 322b in series to provide a first battery voltage at the battery output 25 in a first mode of operation and to selectively interconnect the first and second plurality of cells 322a, 322b in parallel to provide a second battery voltage at the battery output 25 in a second mode of operation. In this example, the first and second plurality of cells 322a, 322b are each 400V cells, the first battery voltage may be 800V and the second battery voltage may be 400V.

Figure 4A illustrates how the control system 26 may be implemented. The control system 26 of Figure 4A illustrates a controller 30. In other examples, the control system 26 may comprise a plurality of controllers on-board and/or off-board the vehicle 10.

The controller 30 of Figure 4A includes at least one electronic processor 32; and at least one electronic memory device 34 electrically coupled to the electronic processor and having instructions 36 (e.g. a computer program) stored therein, the at least one electronic memory device 34 and the instructions 36 configured to, with the at least one electronic processor 32, cause any one or more of the methods described herein to be performed.

According to an example implementation, the controller 30 of Figure 4A is a battery management system (BMS). The BMS may be internal to or external from a protective housing of the battery 20.

Figure 4B illustrates a non-transitory computer-readable storage medium 38 comprising the instructions 36 (computer software).

Figure 5 illustrates a method 500 of controlling an electrical power circuit for a vehicle 10 as disclosed herein, such as the electrical power circuits illustrated in Figures 2 and 3. The method 500 comprises determining 502 that power is to be applied to a high voltage traction bus 27, causing 504 electrical power to be applied to a DCDC convertor 22, and controlling the DCDC convertor 22 to cause it to supply 506 a pre-charge current to the high voltage traction bus 27.

Figure 6 illustrates a method 600 of controlling an electrical power circuit for a vehicle 10 as disclosed herein, such as the electrical power circuits illustrated in Figures 2 and 3. The method 600 of Figure 6 may be performed following performance of the method 500. The method 600 comprises monitoring 602 a parameter associated with the HV traction bus 27, electrically connecting 604 the HV traction bus 27 to the traction battery 20 in dependence on the monitored parameter, and stopping supply of the pre-charge current to the HV traction bus 27 by the DCDC convertor 22.

For purposes of this disclosure, it is to be understood that the controller(s) 30 described herein can each comprise a control unit or computational device having one or more electronic processors. A vehicle 10 and/or a system thereof may comprise a single control unit or electronic controller or alternatively different functions of the controller(s) may be embodied in, or hosted in, different control units or controllers. A set of instructions could be provided which, when executed, cause said controller(s) or control unit(s) to implement the control techniques described herein (including the described method(s)). The set of instructions may be embedded in one or more electronic processors, or alternatively, the set of instructions could be provided as software to be executed by one or more electronic processor(s). For example, a first controller may be implemented in software run on one or more electronic processors, and one or more other controllers may also be implemented in software run on one or more electronic processors, optionally the same one or more processors as the first controller. It will be appreciated, however, that other arrangements are also useful, and therefore, the present disclosure is not intended to be limited to any particular arrangement. In any event, the set of instructions described above may be embedded in a computer-readable storage medium (e.g., a non-transitory computer-readable storage medium) that may comprise any mechanism for storing information in a form readable by a machine or electronic processors/computational device, including, without limitation: a magnetic storage medium (e.g., floppy diskette); optical storage medium (e.g., CD-ROM); magneto optical storage medium; read only memory (ROM); random access memory (RAM); erasable programmable memory (e.g., EPROM and EEPROM); flash memory; or electrical or other types of medium for storing such information/instructions.

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.

As used here 'module' refers to a unit or apparatus that excludes certain parts/components that would be added by an end manufacturer or a user.

As used here, 'connected' means 'electrically interconnected' either directly or indirectly. Electrical interconnection does not have to be galvanic. Where the control system is concemed, connected means operably coupled to the extent that messages are transmitted and received via the appropriate communication means.

The term 'current' means electrical current. The term 'voltage' means potential difference. The term 'series' means electrical series. The term 'parallel' means electrical parallel. 'Active' and 'operational' generally mean closed circuit. The term 'power' means electrical power. The term 'charging' means electrical recharging of the battery.

The blocks illustrated in Figures 5, or 6 may represent steps in a method 500, 600 and/or sections of code in a computer program 36 configured to control an electrical power circuit as described above to perform the method steps The illustration of a particular order to the blocks does not necessarily imply that there is a required or preferred order for the blocks and the order and arrangement of the block may be varied. Furthermore, it may be possible for some steps to be omitted or added in other examples. Therefore, this disclosure also includes computer software that, when executed, is configured to perform any method disclosed herein, such as that illustrated in Figures 5 and 6. Optionally the computer software 36 is stored on a computer readable medium, and may be tangibly stored.

Although embodiments of the present invention 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 invention as claimed.

Features described in the preceding description may be used in combinations other than the combinations explicitly described.

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

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

Whilst endeavoring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

CLAIMS1. An electrical power circuit for a vehicle, comprising: a terminal for electrical connection to a traction battery; a DCDC converter coupled to the terminal, the DCDC convertor arranged to receive a first voltage and to provide a second voltage to a high voltage auxiliary power bus; a HV traction bus for providing electrical power to one or more traction motors; and wherein the DCDC converter is coupled to the high voltage traction bus via the auxiliary power bus, the DCDC converter arranged, in response to an indication that power is to be applied to the high voltage traction bus, to provide the second voltage to the high voltage auxiliary power bus in order to provide a pre-charge current to the high voltage traction bus.
2. The electrical power circuit of claim 1 further comprising first switching means coupled between the terminal and the high voltage traction bus; and wherein the first switching means are arranged, in dependence on a parameter associated with the high voltage fraction bus, to electrically connect the terminal to the high voltage traction bus.
3. The electrical power circuit of claim 2, wherein the parameter comprises one of: temperature, a magnitude of the pre-charge current, a time for which the pre-charge current has been supplied to the high voltage traction bus, and a voltage of the high voltage traction bus.
4. The electrical power circuit of claim 3, wherein the parameter associated with the high voltage traction bus comprises the voltage of the high voltage traction bus; and wherein the first switching means are arranged, in dependence on the voltage of the high voltage traction bus being greater than a threshold voltage, to electrically connect the terminal to the high voltage traction bus.
5. The electrical power circuit of any preceding claim, comprising: second switching means coupled in series with a resistive load, the second switching means and the resistive load coupled between the terminal and the DCDC converter; and third switching means coupled between the terminal and the DCDC converter in parallel with the second switching means and the resistive load.
6. The electrical power circuit of any preceding claim, comprising an onboard charger coupled to the DCDC convertor, the onboard charger arranged to receive AC power and to provide the first voltage to the DCDC convertor, the DCDC converter arranged to convert the first voltage provided by the onboard charger to provide the pre-charge current to the high voltage traction bus.
7. The electrical power circuit of any of claims Ito 5, wherein the first voltage is provided by a traction battery coupled to the terminal, the DCDC converter arranged to convert the first voltage provided by the traction battery to provide the pre-charge current to the high voltage traction bus.
8. A battery assembly comprising a traction battery and the electrical power circuit of any preceding claim, wherein the traction battery is coupled to the terminal.
9. The battery assembly of claim 8, wherein the traction battery comprises a first plurality of cells, a second plurality of cells, and a battery control circuit to selectively interconnect the first and second plurality of cells in series to provide a first battery voltage at a battery output in a first mode of operation and to selectively interconnect the first and second plurality of cells in parallel to provide a second battery voltage at the battery output in a second mode of operation.
10. The battery assembly of claim 9, wherein the battery control circuit is further to connect the first plurality of cells to the battery output and isolate the second plurality of cells from the battery output to provide the second battery voltage.
11. A control system for controlling an electrical power circuit of a vehicle, the control system comprising: input means to receive a first signal indicating that power is to be applied to a high voltage traction bus of the vehicle; output means for outputting a control signal for controlling a DCDC converter of the electrical power circuit; and processing means arranged, in dependence on the first signal indicating that power is to be applied to the high voltage traction bus, to: control the output means to output the control signal to cause the DCDC converter to supply a first voltage to a high voltage auxiliary bus in order to supply a pre-charge current to a high voltage traction bus of the vehicle.
12. The control system of claim 11, wherein the input means is arranged to receive a second signal indicative of a parameter associated with the high voltage traction bus of the vehicle; and the processing means is arranged to: determine a parameter of the high voltage traction bus in dependence on the second signal; and in dependence on the determined parameter of the high voltage traction bus, control the output means to output a control signal to cause a first switching means coupled between the high voltage traction bus and a traction battery to electrically couple the high voltage traction bus to the traction battery.
13. The control system of claim 12, wherein the parameter of the high voltage traction bus is based on at least one of: temperature, a magnitude of the pre-charge current, a time for which the pre-charge current has been supplied to the high voltage traction bus, and a voltage of the high voltage traction bus.
14. The control system of claim 13, wherein the parameter of the high voltage traction bus comprises the voltage of the high voltage traction bus; and the processing means arranged to control the output means to output a control signal to cause a first switching means coupled between the high voltage traction bus and a traction battery to electrically couple the high voltage traction bus to the traction battery in response to the voltage of the high voltage traction bus being greater than a threshold voltage.
15. The control system of any of claims 12 to 14, further comprising parameter sensing means arranged to monitor the parameter of the high voltage traction bus and output the second signal indicative of the parameter of the high voltage traction bus.
16. The control system of any of claims 11 to 15, wherein the control system is further to: control the output means to output a control signal to cause a second switching means coupled between a traction battery and the DCDC convertor to electrically couple the DCDC converter to the traction battery, the second switching means connected in series with a resistive load; and control the output means to output a control signal to cause a third switching means coupled in parallel with the second switching means and the resistive load, between the traction battery and the DCDC convertor to close.
17. The control system of claim 16, wherein the control system is further to, subsequent to the third switching means being caused to close, control the output means to output a control signal to cause the second switching means to open.
18. The control system of any of claims 11 to 17, wherein the input means are further configured to receive a signal indicating that an onboard charger coupled to the DCDC convertor is receiving AC power; and the processing means are further arranged, in dependence on the signal indicating that an onboard charger is receiving AC power to control the output means to output a control signal to cause the DCDC convertor to convert a first voltage provided by the onboard charger to provide the pre-charge current.
19. The control system of any of claims 11 to 18, wherein the control system is coupled to a traction battery comprising a first plurality of cells, a second plurality of cells and a battery circuit operable in response to a control signal to selectively interconnect the first and second plurality of cells in series to provide a first battery voltage at a battery output in a first mode or operation, and to selectively interconnect the first and second plurality of cells in parallel to provide a second battery voltage at the battery output in a second mode of operation; and wherein the output means is arranged to provide the control signal to the battery circuit.
20. A vehicle comprising the electrical power circuit of any of claims 1 to 7, the battery assembly of any of claims 8 to 10, or the control system of any of claims 11 to 19.
21. A method of controlling an electrical power circuit for a vehicle, comprising: determining that power is to be applied to a high voltage traction bus of the vehicle; in response to determining that power is to be applied to the HV traction bus: causing electrical power to be applied to a DCDC convertor, the DCDC convertor configured to supply a first voltage to a high voltage auxiliary bus in order to provide a pre-charge current to the high voltage traction bus.
22. The method of claim 21 further comprising: monitoring a parameter of the high voltage traction bus; and connecting the high voltage traction bus to a traction battery in dependence on the monitored parameter.
23. The method of claim 22, wherein the parameter of the high voltage traction bus comprises a voltage of the HV traction bus and wherein connecting the high voltage traction bus to the traction battery in dependence on the monitored parameter comprises connecting the high voltage traction bus to the traction battery in dependence on the voltage of the high voltage traction bus being greater than a threshold voltage.
24. The method of any of claims 21 to 23, wherein causing electrical power to be applied to the DCDC convertor comprises supplying electrical power from the traction battery.
25. Computer software which, when executed by a computer, is arranged to perform a method according to any of claims 21 to 24; optionally the computer software is stored on a computer readable medium. 14