Method and apparatus for controlling a maximum electric current used by an electrical power steering system of an electric vehicle

Abstract

Aspects of the present invention relate to a control system, to a vehicle, to a method, and to a computer readable medium, for controlling a peak electric current used by an electric power assisted steering system (EPAS) of an electric vehicle. The method comprises obtaining a signal representative of a charge level of a traction battery of the vehicle, determining, based on the obtained signal, a value of a maximum electric current to be used by the EPAS, and providing, to the EPAS, an indication of the value of the maximum electric current to be used by the EPAS.

Description

[0001] METHOD AND APPARATUS FOR CONTROLLING A MAXIMUM ELECTRIC CURRENT USED BY AN ELECTRICAL POWER STEERING SYSTEM OF AN ELECTRIC VEHICLE

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to a method and apparatus for controlling a maximum electric current used by an electrical power steering system of an electric vehicle. In particular, the present disclosure relates to a method and apparatus for controlling a maximum, or peak, electrical current that can be used by an electric power steering system (EPAS) of an electric vehicle based on a charge level, or State of Charge (SOC), of a traction battery of the electric vehicle that supplies electrical powerto the EPAS. Aspects of the invention relate to a control system, to a vehicle, to a method, and to a computer readable medium.

[0004] BACKGROUND

[0005] The use of electric power steering systems has become common in many vehicles, particularly electrically powered vehicles. Such electric power steering systems may draw significant electrical current from a traction battery under certain conditions. When the traction battery is at a low state of charge, supplying a large amount of electrical current from the traction battery may negatively impact the remaining range that may be achieved by a battery electric vehicle.

[0006] It is an aim of the present invention to address one or more of the disadvantages associated with the prior art.

[0007] SUMMARY OF THE INVENTION

[0008] Aspects and embodiments of the invention provide a control system, a vehicle, a method, and a computer program product as claimed in the appended claims.

[0009] Embodiments of the invention provide a method for controlling a maximum, or peak, electrical current that can be used by a an electric power assisted steering system (EPAS) of a battery electric vehicle based on a State of Charge of a traction battery of the vehicle.

[0010] According to an aspect of the present invention there is provided a control system for controlling a peak electric current used by an electric power assisted steering system (EPAS) of a battery electric vehicle, the control system comprising one or more processors collectively configured to obtain a signal representative of a charge level of a traction battery of the vehicle, determine, based on the obtained signal, a value of a maximum electric current to be used by the EPAS, and provide, to the EPAS, an indication of the value of the maximum electric current to be used by the EPAS.

[0011] Advantageously, the maximum current that can be drawn by the EPAS system can be controlled based on a measured state of charge of the vehicle traction battery. This allows the control system to actively manage the maximum current to be used by the EPAS during periods of low state of charge. This may have two effects: reducing the proportion of a reduced current capacity of the battery when at low charge that must be reserved for the EPAS, allowing for less throttling of the powertrain or deeper cycling of the battery; and / or reducing the amount of charge used by the EPAS system which may result in improved range of the vehicle.

[0012] According to an embodiment, the control system comprises one or more controllers collectively comprising at least one electronic processor having an electrical input for receiving an input signal; and at least one memory device electrically coupled to the at least one electronic processor and having instructions stored therein; and wherein the at least one electronic processor is configured to access the at least one memory device and execute the instructions thereon so as to: obtain a signal representative of a charge level of a traction battery of the vehicle; determine, based on the obtained signal, a value of a maximum electric current to be used by the EPAS; and provide, to the EPAS, an indication of the value of the maximum electric current to be used by the EPAS.

[0013] Optionally, the one or more processors are configured to determine, based on a comparison of the obtained signal with a threshold value representing a low charge state of the battery, that the charge level of the traction battery is below a predetermined level, and in response to determining that the charge level of the traction battery is below a predetermined level, setting the value of the maximum electric current to be used by the EPAS to a reduced value less than a value of a normal maximum operating current associated with the EPAS.

[0014] Advantageously, the control system may limit the maximum current to be used by the EPAS when the traction battery is determined to be at a low state of charge to avoid negative impact on the traction battery.

[0015] Optionally, the one or more processors are configured to determine a maximum amount of electrical current to be drawn from the traction battery based on the charge level of the traction battery, and wherein the determining the value of the maximum electric current to be used by the EPAS is further based on the maximum amount of electric current to be drawn from the traction battery.

[0016] Advantageously, the maximum amount of electric current to be used by the EPAS may be controlled based on a determined current capacity supported by the traction battery at a current state of charge, i.e. a current budget for the battery in its current state.

[0017] Optionally, the one or more processors are configured to determine an amount of electric current to be supplied to a powertrain of the vehicle, and wherein the determining the value of the maximum electric current to be used by the EPAS is further based on the amount of electric current to be supplied to the powertrain of the vehicle.

[0018] Advantageously, the maximum amount of electric current to be used by the EPAS may be controlled taking into account both the current budget of the battery and an amount of current being supplied to the powertrain ofthe vehicle. E.g. during high acceleration when the powertrain is drawing a large amount of power, a reduced limit may be set for the EPAS as there are unlikely to be large steering inputs during high acceleration. According to embodiments, the indication of the value of the maximum electric current comprises a reduction factor indicating a current value relative to a normal maximum operating current associated with the EPAS.

[0019] Advantageously, the peak electric current value may be provided as a reduction factor corresponding to a ratio between the determined peak electric current value and a normal rated peak electric current for the EPAS. This provides a simple way to indicate a proportional reduction in the peak electric current value, facilitating graceful degradation of the EPAS operation.

[0020] Optionally, the one or more processors are configured to, in response to a determination that the value of the maximum electric current is less than a normal maximum operating current associated with the EPAS, provide an indication to an operator of the vehicle of reduced operating capability associated with the EPAS.

[0021] Advantageously, when the peak electric current to be used by the EPAS is reduced from a normal rated peak current, an indication of reduced operative status can be provided to the driver such that the driver is aware of the status of the vehicle.

[0022] According to a further aspect of the present invention there is provided a vehicle comprising an electric power steering system (EPAS), a traction battery to supply electrical power to a powertrain of the vehicle and the EPAS, and the control system described above, the one or more processors to obtain the signal representative of the charge level of the traction battery and to provide the indication of the value of the maximum electric current to the EPAS.

[0023] According to a still further aspect of the present invention there is provided a method of controlling a peak electric current used by an electric power assisted steering system (EPAS) of a battery electric vehicle, the method comprising obtaining a signal representative of a charge level of a traction battery of the vehicle, determining, based on the obtained signal, a value of a maximum electric current to be used by the EPAS, and providing, to the EPAS, an indication of the value of the maximum electric current to be used by the EPAS.

[0024] Advantageously, the method allows maximum current that can be drawn by the EPAS system to be controlled based on a measured state of charge of the vehicle traction battery to actively manage the maximum current to be used by the EPAS during periods of low state of charge. This may have two effects: reducing the proportion of a reduced current capacity of the battery when at low charge that must be reserved forthe EPAS, allowing for less throttling of the powertrain or deeper cycling of the battery; and / or reducing the amount of charge used by the EPAS system which may result in improved range of the vehicle.

[0025] Optionally, the method comprises determining, based on a comparison of the obtained signal with a threshold value representing a low charge state of the battery, that the charge level of the traction battery is below a predetermined level, and in response to determining that the charge level of the traction battery is below a predetermined level, setting the value of the maximum electric current to be used by the EPAS to a reduced value less than a normal maximum operating current associated with the EPAS.

[0026] Advantageously, the method may limit the maximum current to be used by the EPAS when the traction battery is determined to be at a low state of charge to avoid negative impact on the traction battery. Optionally, the method comprises determining a maximum amount of electrical current to be drawn from the traction battery based on the charge level of the traction battery, and wherein the determining the value of the maximum electric current to be used by the EPAS is further based on the maximum amount of electric current to be drawn from the traction battery.

[0027] Advantageously, the method controls the maximum amount of electric current to be used by the EPAS based on a determined current capacity supported by the traction battery at a current state of charge, i.e. a current budget for the battery in its current state.

[0028] Optionally, the method comprises determining an amount of electric current to be supplied to a powertrain of the vehicle, and wherein the determining the value of the maximum electric current to be used by the EPAS is further based on the amount of electric current to be supplied to the powertrain of the vehicle.

[0029] Advantageously, the method controls the maximum amount of electric current to be used by the EPAS taking into account both the current budget of the battery and an amount of current being supplied to the powertrain of the vehicle. E.g. during high acceleration when the powertrain is drawing a large amount of power, a reduced limit may be set for the EPAS as there are unlikely to be large steering inputs during high acceleration.

[0030] According to embodiments, the indication of the value of the maximum electric current comprises a reduction factor indicating a current value relative to a normal maximum operating current associated with the EPAS.

[0031] Advantageously, the peak electric current value may be provided by the method as a reduction factor corresponding to a ratio between the determined peak electric current value and a normal rated peak electric current forthe EPAS. This provides a simple way to indicate a proportional reduction in the peak electric current value, facilitating graceful degradation of the EPAS operation.

[0032] Optionally, the method comprises, in response to a determination that the value of the maximum electric current is less than a normal maximum operating current associated with the EPAS, providing an indication to an operator of the vehicle of reduced operating capability associated with the EPAS.

[0033] Advantageously, when the peak electric current to be used by the EPAS is reduced from a normal rated peak current, the method provides an indication of reduced operative status can be provided to the driver such that the driver is aware of the status of the vehicle.

[0034] According to another aspect of the invention, there is provided a computer program product comprising computer program instructions that when executed on a processor of a control system of a battery electric vehicle including an electric power steering system, causes the control system to perform the method as described above.

[0035] Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and / or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and / or features of any embodiment can be combined in any way and / or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and / or incorporate any feature of any other claim although not originally claimed in that manner.

[0036] BRIEF DESCRIPTION OF THE DRAWINGS

[0037] One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0038] Figure 1 shows a system suitable for implementing embodiments of the invention;

[0039] Figure 2 illustrates a vehicle including the system of Figure 1 and suitable for implementing embodiments of the invention;

[0040] Figure 3 shows a method of controlling a maximum amount electrical power used by electric power steering system according to embodiments of the invention;

[0041] Figure 4 shows a further method of controlling a maximum amount electrical power used by electric power steering system according to embodiments of the invention; and

[0042] Figure 5 illustrates a control system suitable for performing the method of Figure 4, according to embodiments of the invention.

[0043] DETAILED DESCRIPTION

[0044] According to embodiments of the invention, a control system may control a maximum, or peak, electrical current that can be used by an electric power steering system (EPAS) of an electric vehicle based on a charge level, or State of Charge (SOC), of a traction battery of the electric vehicle that supplies electrical power to the EPAS.

[0045] At low state of charge, a traction battery’s ability to supply high current may be limited. Due to internal resistance within the cells of the traction battery, high currents may cause the voltage across the individual cells to drop due to losses in the battery cell. Typically, a battery management system (BMS) of an electric vehicle monitors the voltage of each individual cell of the traction battery. If the voltage associated with a particular cell drops below a certain level, or threshold voltage, the BMS takes mitigating action to avoid damage to the battery cell, such as limiting the electric vehicle to a limp home mode or even shutting down the electric vehicle until the traction battery can be charged.

[0046] Electric power steering systems (EPAS) may have power requirements that fluctuate significantly during use. For example, an EPAS may require minimal power when driving along a relatively straight road, but may have significant peak requirements, for example in response to steering input when stationary. Some example EPAS systems are capable of using an electrical current of up to 75 Amps, or even 150 Amps, under certain conditions, representing a significant electrical current to be supplied from the traction battery 102.

[0047] Under certain circumstances, a high peak current use by the EPAS of an electric vehicle, when combined with other electrical power users of the vehicle such as the powertrain, can cause a voltage associated with a traction battery, e.g. a voltage of one or more cells of the traction battery, to fall below the threshold amount leading to premature shutdown of the vehicle, resulting in a poor user experience. By limiting a maximum, or peak, electric current that can be used by the EPAS, based on a charge level of the traction battery, embodiments of the invention may avoid this premature shutdown of the vehicle, increasing the range available to a driver of the vehicle at low state of charge.

[0048] With reference to Figure 1 , there is illustrated a control system 100 for a vehicle in accordance with an embodiment of the present invention. The control system 100 comprises one or more controller 110 that is communicatively coupled to a traction battery 102, or to a controller operable to monitor an SOC of the traction battery, to receive a signal 108 representative of a charge level of the traction battery 102. The one or more controller 110 is further communicatively coupled to an EPAS 104 of the vehicle that receives electrical power 106 from the traction battery 102, the controller 110 operable to provide a control signal 116 to the EPAS 104.

[0049] The control system 100 as illustrated in Figure 1 comprises one controller 110, although it will be appreciated that this is merely illustrative. The controller 1 10 comprises processing means 112 and memory means 114. The processing means 112 may be one or more electronic processing device 112 which operably executes computer-readable instructions. The memory means 114 may be one or more memory device 114. The memory means 114 is electrically coupled to the processing means 112. The memory means 1 14 is configured to store instructions, and the processing means 1 12 is configured to access the memory means 1 14 and execute the instructions stored thereon.

[0050] The controller 1 10 comprises an input means and an output means. The input means may comprise an electrical input of the controller 110. The output means may comprise an electrical output of the controller 1 10. The input is arranged to receive a signal 108 representative of a charge level of the traction battery 102. The charge level signal 108 is an electrical signal which is indicative of charge level. The output is arranged to output a maximum current control signal 116 that is indicative of a value of a maximum electric current to be used by the EPAS 104.

[0051] Upon receiving the maximum current control signal 116, including an indication of the value of the maximum electric current to be used by the EPAS 104, the EPAS 104 may modify its operation to ensure that the received value of maximum electric current is not exceeded. For example, the EPAS 104 may “clip” an operating envelope such that operation is not affected unless the current demand would exceed the maximum electric current value for example by limiting the maximum assistance that can be provided by an actuator in the EPAS 104. In an alternative embodiment, the EPAS 104 may scale its operating capability, for example by scaling the assistance provided by the actuator across its operating range by a scaling factor corresponding to the ratio of the received value of maximum electric current to a normal operating maximum electric current value that may be used by the EPAS 104 during normal, unrestricted, operation.

[0052] Figure 2 illustrates an electric vehicle 200 according to an embodiment of the present invention. The electric vehicle 200 comprises a controller 110 as illustrated in Figure 1 . The traction battery 102 supplies electrical power to EPAS 104, one or more further components 202 of the vehicle 200 as well as to a powertrain (not shown) operable to provide motive force for the electric vehicle 200.

[0053] According to embodiments of the invention, a signal representative of a charge level, or SOC, of the traction battery 102 is obtained and based on the obtained charge level a value of a maximum electric current to be used by the EPAS 104 is determined. The determined value of the maximum electric current may be less than a normal, or design, maximum current that the EPAS 104 is able to use during normal operation. The determined value of the maximum electric current is then provided to the EPAS 104, causing the EPAS 104 to limit the maximum amount of electrical current to be drawn from the traction battery 102.

[0054] While the reduction in maximum electrical current used by the EPAS may result in reduced capability for a short period, by reducing the instantaneous peak current being drawn from the traction battery 102, the likelihood of a voltage associated with the traction battery 102 falling below a threshold voltage level that would trigger action by the battery management system is reduced. Thus, the control system 100 of Figure 1 allows for a graceful degradation of the EPAS capability to avoid, or at least reduce the risk of, shutdown of the electric vehicle by the battery management system.

[0055] Figure 3 illustrates a method 300 according to an embodiment of the invention. The method 300 is a method of controlling a maximum amount of electric power used by an EPAS of a vehicle 200, such as the vehicle 200 illustrated in Figure 2. The method 300 may be performed by the system 100 illustrated in Figure 1. In particular, the memory 114 may comprise computer-readable instructions which, when executed by the processor 112, perform the method 300 according to an embodiment of the invention.

[0056] According to the illustrated method 300, at block 302 a charge level associate with a traction battery 102 of a vehicle 200 is obtained. The obtained charge level is provided to block 304 where the obtained charge level is checked to determine if action should be taken to reduce high currents being drawn from the traction battery 102, for example based on a comparison of the charge level with a threshold charge level value 306.

[0057] At block 308, it is determined based on an output of block 304 whether a reduction in peak current use by the EPAS 104 should be applied. If no reduction is indicated, the method returns to determination block 304 where further charge level values for the traction battery 102 are obtained and used to determine a further value of the maximum electric current to be used by the EPAS 104. If it is determined at block 308 that a reduction in peak current use by the EPAS 104 should be applied, the method moves to block 310 where the reduced value of maximum current to be used by the EPAS is determined based on the determination that the value of maximum current should be reduced, and on a minimum power level required for the EPAS 104.

[0058] The determined value of the maximum electric current is then provided to the EPAS 104. The determined value of maximum electric current to be used by the EPAS 104 is further provided to block 304 and 306 and may be used in determining whether a further reduction in peak current use is desired, for example by including knowledge of expected current flows to the EPAS 104.

[0059] A further output from block 310 may be a signal to a human-machine interface (HMI) (not shown) to provide an indication to an operator of the vehicle 200 of a reduced operating capability of the EPAS associated with the reduction in the value of the maximum electric current to be used by the EPAS.

[0060] Figure 4 illustrates a method 400 of controlling a maximum amount of electrical power used by an EPAS 104 of a vehicle 200. According to the illustrated method 400, a signal representative of a charge level of a traction battery 102 of the vehicle is obtained 402. Based on the obtained signal, a value of a maximum electric current to be used by the EPAS 104 is determined 404. An indication of the value of the maximum electric current value to be used by the EPAS 104 is then provided 406 to the EPAS. In some embodiments, the indication of the value of the maximum electric current may comprise a reduction factor indicating a current value relative to a normal, or rated, maximum operating current associated with the EPAS. Optionally, the reduction factor may be applied operation of the EPAS such that electrical power use by the EPAS across its full operational range is scaled by the reduction factor, for example for an actuator of the vehicle, in response to an actuation that would normally cause the EPAS to use 50% of the maximum electric current this may be further reduced by the reduction factor to cause the EPAS to use 50% of the reduced value of the maximum electric current to be used by the EPAS 104.

[0061] In some embodiments, a minimum current required by the EPAS to allow operation of the EPAS may be obtained by the control system 110 and the determination of the value of the maximum electric current may be further based on the minimum current required. For example, if it would be determined that the maximum current would be reduced below the minimum current, a determination may be made to maintain the level of the maximum electric current at the minimum level to maintain a minimum operation capability for the EPAS. Alternatively, it may be determined to switch the EPAS power to a backup battery (not shown) to reserve any remaining capacity of the traction battery 102 for other components / systems of the vehicle 200.

[0062] The EPAS 104 may be one of a number of components or subsystems of the vehicle, other than the vehicle powertrain, that are significant users of electrical power, for example a ventilation and air conditioning (HVAC) system. In some embodiments, a maximum amount of electrical current that can be supported by the traction battery to supply these significant users of electrical power, e.g. a “current budget”, may be determined based on the charge level of the traction battery 102. The maximum amount of current to be used by the EPAS may be further based on the determined “current budget”, taking into account electrical current used by other components or subsystems of the electric vehicle 200.

[0063] In some embodiments, an amount of electrical current being supplied to a powertrain of the vehicle 200 may be determined and the value of the maximum electric current to be used by the EPAS further based on the amount of electric current to be supplied to the powertrain of the vehicle. In such embodiments, in scenarios where relatively low amounts of current are supplied to the powertrain of the vehicle, such as during low speed manoeuvring, the value of the maximum electric current to be used by the EPAS may be determined to be a higher value than at times when a greater amount of current is supplied to the powertrain, while still protecting the traction battery from excessively high current draw at low state of charge.

[0064] Certain methods and systems as described herein may be implemented by one or more processors that processes program code that is retrieved from a non-transitory storage medium. Figure 5 shows an example 500 of a device comprising a computer-readable storage medium 520 coupled to at least one processor 510. The computer-readable media 520 can be any media that can contain, store, or maintain programs and data for use by or in connection with an instruction execution system. Computer-readable media can comprise any one of many physical media such as, for example, electronic, magnetic, optical, electromagnetic, or semiconductor media. More specific examples of suitable machine-readable media include, but are not limited to, a hard drive, a random-access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory, or a portable disc. In Figure 5, the computer-readable storage medium comprises program code to perform a method corresponding to the embodiment shown in Figure 4, that is: obtaining 402 a signal representative of a charge level associated with a traction battery 102 of the vehicle 200, the traction battery 102 to supply electrical power to an electric power steering system 104 of the vehicle; determining 404, based on the obtained signal, a value of a maximum electric current to be used by the EPAS; and providing 406, to the EPAS, an indication of the value of the maximum electric current value to be used by the EPAS.

[0065] In embodiments, the control system may be implemented as an analogue electronic circuit, for example comprising one or more comparators, Op-Amps, etc. configured to implement the method of Figure 3 or Figure 4.

[0066] In embodiments, the computer-readable storage medium may comprise program code to perform a method corresponding to the embodiment of Figure 3.

[0067] 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

CLAIMS1 . A control system for controlling a peak electric current used by an electric power assisted steering system, EPAS, of a battery electric vehicle, the control system comprising one or more processors collectively configured to: obtain a signal representative of a charge level of a traction battery of the vehicle; determine, based on the obtained signal, a value of a maximum electric current to be used by the EPAS; and provide, to the EPAS, an indication of the value of the maximum electric current to be used by the EPAS.

2. The control system of claim 1 , wherein the one or more processors are further configured to: determine, based on a comparison of the obtained signal with a threshold value representing a low charge state of the battery, that the charge level of the traction battery is below a predetermined level; and in response to determining that the charge level of the traction battery is below a predetermined level, setting the value of the maximum electric current to be used by the EPAS to a reduced value less than a value of a normal maximum operating current associated with the EPAS.

3. The control system of claim 1 or claim 2, wherein the one or more processors are further configured to: determine a maximum amount of electrical current to be drawn from the traction battery based on the charge level of the traction battery; and wherein the determining the value of the maximum electric current to be used by the EPAS is further based on the maximum amount of electric current to be drawn from the traction battery.

4. The control system of claim 3, wherein the one or more processors are further configured to: determine an amount of electric current to be supplied to a powertrain of the vehicle; and wherein the determining the value of the maximum electric current to be used by the EPAS is further based on the amount of electric current to be supplied to the powertrain of the vehicle.

5. The control system of any preceding claim, wherein the indication of the value of the maximum electric current comprises a reduction factor indicating a current value relative to a normal maximum operating current associated with the EPAS.

6. The control system of any preceding claim, wherein the one or more processors are further configured to, in response to a determination that the value of the maximum electric current is less than a normal maximum operating current associated with the EPAS, provide an indication to an operator of the vehicle of reduced operating capability associated with the EPAS.

7. A vehicle comprising:an electric power steering system, EPAS,; a traction battery to supply electrical power to a powertrain of the vehicle and the EPAS; and the control system of any of claims 1 to 6, the one or more processors to obtain the signal representative of the charge level of the traction battery and to provide the indication of the value of the maximum electric current to the EPAS.

8. A method of controlling a peak electric current used by an electric power assisted steering system, EPAS, of a battery electric vehicle, the method comprising: obtaining a signal representative of a charge level of a traction battery of the vehicle; determining, based on the obtained signal, a value of a maximum electric current to be used by the EPAS; and providing, to the EPAS, an indication of the value of the maximum electric current to be used by the EPAS.

9. The method of claim 8, further comprising: determining, based on a comparison of the obtained signal with a threshold value representing a low charge state of the battery, that the charge level of the traction battery is below a predetermined level; and in response to determining that the charge level of the traction battery is below a predetermined level, setting the value of the maximum electric current to be used by the EPAS to a reduced value less than a normal maximum operating current associated with the EPAS.

10. The method of claim 8 or claim 9, further comprising: determining a maximum amount of electrical current to be drawn from the traction battery based on the charge level of the traction battery; and wherein the determining the value of the maximum electric current to be used by the EPAS is further based on the maximum amount of electric current to be drawn from the traction battery.11 . The method of claim 10, further comprising: determining an amount of electric current to be supplied to a powertrain of the vehicle; and wherein the determining the value of the maximum electric current to be used by the EPAS is further based on the amount of electric current to be supplied to the powertrain of the vehicle.

12. The method of any of claims 8 to 11 , wherein the indication of the value of the maximum electric current comprises a reduction factor indicating a current value relative to a normal maximum operating current associated with the EPAS.

13. The method of any of claims 8 to 12, further comprising: in response to a determination that the value of the maximum electric current is less than a normal maximum operating current associated with the EPAS, providing an indication to an operator of the vehicle of reduced operating capability associated with the EPAS.

14. A computer program product comprising computer program instructions that when executed on a processor of a control system of a battery electric vehicle including an electric power steering system, causes the control system to perform the method of any of claims 8 to 13.

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