Patent Description:
While driving on surfaces with a variable coefficient of friction, for example, one or more wheels of a vehicle may slip and so accelerate.

Since the inertia of an electric drive system is relatively low compared with the inertia of a convention engine and transmission system, the speed of wheels powered by an electric drive system can increase rapidly during a wheel slip event.

In conventional traction control systems, driving torque is reduced as soon as slip is detected. Due to higher inertia in conventional engine and transmission systems the wheels do not reach high speeds and so the time to respond to the wheel slip event is not so critical and the decelerating power requirement is also not high.

However, in electric drive systems, due to the low inertia of the system, the wheels can accelerate rapidly during a wheel slip event causing a rapid increase of electrical power consumption that can, for example, exceed the capability of the traction battery to deliver the required power.

<CIT> describes a method and apparatus for optimizing the torque applied to the primary and assist drive systems of an all-electric vehicle, the torque adjustments taking into account wheel slip as well as other vehicular operating conditions.

<CIT> describes a vehicle torque safety monitor. The safety monitor includes a vehicle power estimator configured to estimate a first mechanical power of a first electric motor and a second mechanical power of a second electric motor. The safety monitor includes an energy storage system power estimator and limiter, configured to estimate electrical power provided by an energy storage system, at least a portion of the electrical power converting to the first mechanical power and the second mechanical power. The system includes a vehicle power monitor, configured to indicate an inconsistency in the first mechanical power, the second mechanical power, and the electrical power.

<CIT> describes an electric motor controller adapted to provide anti-lock braking of an electric traction motor for an electric vehicle. The electric motor controller comprises a torque demand input for receiving a torque demand input signal based on a request from an operator of the electric vehicle and a torque demand adjuster adapted to adjust the torque demand input signal and to provide an adjusted torque demand signal. The torque demand adjuster is configured to adjust the torque demand signal such that the motor is controlled to reduce the difference between a motor speed and an estimated speed of the electric vehicle.

Aspects and embodiments of the invention provide a control system, a vehicle system, a vehicle, a method, and computer software, as claimed in the appended claims.

According to an aspect of the invention there is provided a control system for controlling electrical power consumption from energy storage means by a traction motor of a vehicle caused by a wheel slip event, the control system comprising one or more electronic controllers, the one or more electronic controllers configured to: receive a torque request for the traction motor; determine a prevailing speed value of the traction motor; determine a maximum allowable increase in speed of the traction motor to occur during a latency period associated with the prevailing speed value of the traction motor; determine an electrical power consumption limit in dependence on the torque request, the prevailing speed value of the traction motor and the maximum allowable increase in speed of the traction motor; and control torque provision of the traction motor in dependence on the torque request and the electrical power consumption limit; wherein control of the torque provision comprises determining a speed value of the traction motor having a lower associated latency and determining a torque limit in dependence on the lower latency speed value of the traction motor, the torque request and the electrical power consumption limit.

An advantage provided is it can prevent power consumption in excess of the capability of the battery. This can, therefore, prevent battery damage and/or intrusive battery protection features of a vehicle being activated.

The one or more controllers may collectively comprise: at least one electronic processor having an electrical input for receiving information associated with a torque request for the traction motor of the vehicle, determining a prevailing speed value of the traction motor, determining a maximum allowable increase in speed of the traction motor and determining an electrical power consumption limit; and at least one electronic 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 cause the control system to determine the prevailing speed value of the traction motor, determine the maximum allowable increase in speed of the traction motor, determine the electrical power consumption limit and control torque provision of the traction motor.

Determining a maximum allowable increase in speed of the traction motor may comprise determining a prevailing speed of the vehicle and determining the maximum allowable increase in speed of the traction motor in dependence on the prevailing speed of the vehicle.

Determining a maximum allowable increase in speed of the traction motor may comprise accessing at least one data structure in dependence on the prevailing speed of the vehicle.

Determining an electrical power consumption limit may comprise accessing at least one data structure in dependence on the torque request, the prevailing speed value of the traction motor and the maximum allowable increase in speed of the traction motor.

The at least one data structure may account for efficiencies in provision of torque by the traction motor.

The electrical power consumption limit may comprise a limit in terms of electrical current and/or power to be supplied to the traction motor.

The electrical power consumption limit may comprise a limit in terms of electrical current and/or power to be drawn from the energy storage means by the traction motor.

The latency period of the prevailing speed value of the traction motor may be approximately <NUM> to <NUM> milliseconds.

Controlling torque provision may comprise transmitting the torque request and electrical power consumption limit to control torque provision.

According to an aspect of the invention there is provided a vehicle system comprising the control system, a traction motor and energy storage means.

According to an aspect of the invention there is provided a vehicle comprising the control system and/or the vehicle system.

According to an aspect of the invention there is provided a method for controlling electrical power consumption from energy storage means by a traction motor of a vehicle caused by a wheel slip event, the method comprising: receiving a torque request for the traction motor of the vehicle; determining a prevailing speed value of the traction motor; determining a maximum allowable increase in speed of the traction motor to occur during a latency period associated with the prevailing speed value of the traction motor; determining an electrical power consumption limit in dependence on the torque request, the prevailing speed value of the traction motor and the maximum allowable increase in speed of the traction motor; and
controlling torque provision of the traction motor in dependence on the torque request and the electrical power consumption limit; wherein controlling torque provision comprises determining a speed value of the traction motor having a lower associated latency and determining a torque limit in dependence on the lower latency speed value of the traction motor, the torque request and the electrical power consumption limit.

The latency period of the prevailing speed value of the traction motor may be approximately <NUM> to <NUM> milliseconds. Controlling torque provision may comprise transmitting the torque request and electrical power consumption limit to control torque provision.

According to an aspect of the invention there is provided a non-transitory computer readable medium comprising computer readable instructions that, when executed by a processor, perform the method of at least one or more methods described herein.

Examples of the present disclosure relate to controlling electrical power consumption from energy storage means by a traction motor of a vehicle caused by a wheel slip event.

In examples, the energy storage means can be any suitable energy storage means to power one or more electric traction motors or traction motors of the vehicle to propel the vehicle.

In examples, the energy storage means can be considered: one or more components configured to store energy, energy storage circuitry, energy storage apparatus, energy storage mechanism and so on.

In examples, the energy storage means comprises or is one or more traction batteries which may be one or more high voltage batteries.

According to the invention, an electrical power consumption limit is determined and torque provision of the traction motor controlled in dependence on a lower latency speed motor, a torque request and the electrical power consumption limit.

This is advantageous as, for example, it can prevent power consumption in excess of the capability of the battery.

This can, therefore, prevent battery damage and/or intrusive battery protection features of a vehicle being activated.

One or more of the features discussed in relation to <FIG> and <FIG> can be found in the other figures.

<FIG> illustrates an example of a vehicle <NUM> in which embodiments of the invention can be implemented. In the illustrated example, the vehicle <NUM> is a hybrid electric vehicle (HEV).

In some, but not necessarily all, examples, the vehicle <NUM> 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.

In examples, the hybrid electric vehicle has an electric only mode of propulsion among other modes of propulsion. In examples, the HEV is configured to operate as a parallel HEV. Parallel HEVs comprise a torque path between the engine and a least one vehicle wheel, as well as a torque path between an electric traction motor and at least one vehicle wheel. The torque path(s) may be disconnectable via a torque path connector such as a clutch. Parallel HEVs differ from series HEVs, because in series HEVs the purpose of the engine is to generate electrical energy and there is no torque path between the engine and the vehicle wheels.

The vehicle <NUM> comprises at least one traction motor <NUM>, energy storage means <NUM> and a control system <NUM> as described herein. The control system <NUM> is configured to operate as described herein.

Accordingly, <FIG> illustrates a vehicle <NUM> comprising a control system <NUM> as described herein.

<FIG> illustrates an example of a control system <NUM>.

According to the invention, the control system <NUM> is a control system <NUM> for controlling electrical power consumption from energy storage means <NUM> by a traction motor <NUM> of a vehicle <NUM> caused by a wheel slip event.

In examples, any suitable control system <NUM> for controlling electrical power consumption from energy storage means <NUM> by a traction motor <NUM> of a vehicle <NUM> caused by a wheel slip event can be used.

The control system <NUM> of <FIG> comprises an electronic controller <NUM>. In other examples, the control system <NUM> comprises a plurality of electronic controllers <NUM> on-board and/or off-board the vehicle <NUM>.

The electronic controller <NUM> of <FIG> comprises at least one electronic processor <NUM> and at least one electronic memory device <NUM> coupled to the at least one electronic processor <NUM> and having instructions <NUM> (for example a computer program) stored therein, the at least one electronic memory device <NUM> and the instructions <NUM> configured to, with the at least one electronic processor <NUM>, cause any one or more of the method or methods described herein to be performed.

Accordingly, <FIG> illustrates a control system <NUM> for controlling electrical power consumption from energy storage means <NUM> via a traction motor <NUM> of a vehicle <NUM> caused by a wheel slip event, the control system <NUM> comprising one or more electronic controllers <NUM>, the one or more electronic controllers <NUM> configured to:.

Furthermore, <FIG> therefore illustrates a control system <NUM>, wherein the one or more controllers <NUM> collectively comprise:.

In examples the prevailing speed value can be considered to be the current speed value of the traction motor <NUM> received or known by the control system <NUM> or a controller <NUM> of the control system <NUM>.

<FIG> illustrates a non-transitory computer readable storage medium <NUM> comprising the instructions <NUM> (computer software).

Accordingly, <FIG> illustrates a non-transitory computer readable medium <NUM> comprising computer readable instructions <NUM> that, when executed by a processor <NUM>, perform the method of <FIG> and/or as described herein.

<FIG> schematically illustrates an example of a system <NUM>. The system <NUM> can be considered a vehicle system <NUM>.

In the illustrated example, the system <NUM> is a system <NUM> for controlling electrical power consumption from energy storage means via a traction motor <NUM> of a vehicle <NUM> caused by a wheel slip event.

In the example of <FIG>, the system <NUM> comprises a control system <NUM> which may be as described in relation to <FIG>.

<FIG> also illustrates an example of a vehicle <NUM>, such as a hybrid electric vehicle, comprising a control system <NUM> as described herein or a vehicle system <NUM> as described herein.

In the example of <FIG>, the vehicle system <NUM> comprises one or more traction motors <NUM> and one or more vehicle systems <NUM>. The one or more vehicle systems <NUM> can be considered one or more further vehicle system(s) <NUM>.

In the example of <FIG>, the control system <NUM> provides means for controlling operation of the system <NUM>. However, in examples, any suitable means for controlling operation of the system <NUM> can be used.

The control system <NUM> of <FIG> may comprise one or more of: a hybrid powertrain control module; an engine control unit; a transmission control unit; a traction battery management system; and/or the like.

As illustrated in the example of <FIG>, the elements <NUM> and <NUM> are operationally coupled to the control system <NUM> and any number or combination of intervening elements can exist between them (including no intervening elements).

In some examples, the elements <NUM> and <NUM> are operationally coupled to each other and/or share one or more components. Additionally, or alternatively, the element <NUM> and/or <NUM> may be operationally coupled to and/or share one or more components with other elements not illustrated in the example of <FIG>.

In examples, the one or more traction motor motors <NUM> can comprise or be any suitable traction motor(s) <NUM>.

In some examples, the traction motor(s) <NUM> may be an alternating current induction motor or a permanent magnet motor, another type of motor or a combination thereof.

In examples, any suitable traction motor(s) <NUM> suitable for providing torque to drive one or more wheels of the vehicle <NUM> can be used. In examples, the traction motor(s) <NUM> is configured to enable at least an electric vehicle mode comprising electric only driving.

In some examples, a traction motor <NUM> can be considered an electric driver unit or electric traction motor.

In some examples, the traction motor(s) <NUM> is configured to drive an electric only axle of vehicle <NUM> to enable all-wheel drive of the vehicle <NUM> in combination with a second axle driven by an internal combustion engine.

In examples, the control system <NUM> provides means to control, at least in part, directly or indirectly, operation of the traction motor(s) <NUM>. Information may be transmitted between the control system <NUM> and the traction motor(s). For example, control information may be transmitted from the control system <NUM> to the traction motor(s) <NUM> and/or information from the traction motor(s) <NUM> transmitted to the control system <NUM>.

This is illustrated in the example of <FIG> by the double headed arrow linking the traction motor(s) <NUM> and the control system <NUM>.

In examples, the one or more vehicle systems <NUM> are or comprise any suitable vehicle system(s) <NUM> of the vehicle <NUM>. For example, the one or more vehicle systems <NUM> may comprise any suitable vehicle system(s) <NUM> of the vehicle <NUM>, controllable, at least in part, directly or indirectly, by the control system <NUM>.

In examples, the one or more vehicle systems <NUM> may be considered further vehicle systems in the vehicle system <NUM>.

In some examples, the one or more vehicle systems <NUM> may be considered to be further vehicle system(s) <NUM> separate from, but controlled, at least in part, directly or indirectly, by the vehicle system <NUM>.

The one vehicle systems <NUM> can comprise any suitable vehicle system or systems <NUM> from which a torque request <NUM> for the traction motor(s) <NUM> can be received.

For example, a torque request <NUM> may come from a physical driver of the vehicle <NUM>, that is a person who interacts with one or more accelerator controls of the vehicle <NUM>, and/or one or more virtual drivers of the vehicle <NUM>.

In examples, virtual drivers can form at least part of any driver assistance system such as one or more advanced driver assistance systems (ADAS), for example, a cruise control system, an autonomous cruise control system, park assist, an all-terrain progress control system (ATPC), all-surface progress control (ASPC), vehicle speed limiter, intelligent speed limiter and so on. An example of all-terrain progress control system (ATPC) or all-surface progress control (ASPC) is described in <CIT>.

In examples, the one or more vehicle systems <NUM> comprise electrical energy storage means <NUM> configured to store electrical power for the traction motor(s) <NUM>.

In examples, the energy storage means <NUM> comprises or is one or more traction batteries (not illustrated). The traction battery or batteries provide a nominal voltage required by electrical power users such as the traction motor(s) <NUM>.

In examples, the traction motor(s) <NUM> is configured to receive electrical energy from the traction battery of the vehicle system(s) <NUM>.

The traction battery may be a high voltage battery. High voltage traction batteries provide nominal voltages in the hundreds of volts. The traction battery may have a voltage and capacity to support electric only driving for sustained distances. The traction battery may have a capacity of several kilowatt hours to maximize range. The capacity may be in the tens of kilowatt hours, or even over a hundred kilowatt hours.

In examples, the function of the traction battery can be implemented using a plurality of small traction batteries in different locations on the vehicle <NUM>.

Accordingly, <FIG> also illustrates a vehicle system <NUM> comprising a control system <NUM> as described herein, a traction motor <NUM> and energy storage means <NUM>.

In examples, the vehicle system(s) <NUM> provides one or more inverters for each traction motor <NUM>.

In examples, the control system <NUM> provides means to control, at least in part, directly or indirectly, of the one or more vehicle systems <NUM>. Information may be transmitted between the control system <NUM> and the one or more vehicle systems <NUM>. For example, control information may be transmitted from the control system <NUM> to the one more vehicle systems <NUM> and/or information from the one or more vehicle systems <NUM>, such as one or more torque requests <NUM>, transmitted to the control system <NUM>.

This is illustrated in the example of <FIG> by the double headed arrow linking the one or more vehicle systems <NUM> and the control system <NUM>.

In examples, the control system <NUM> provides means for controlling the elements of the vehicle system <NUM>. The control system <NUM> may be configured to control the elements of the vehicle system <NUM> using one or more wired or wireless network systems/protocols. For example, USB, HDMI, Bluetooth, WiFi,, CAN, LIN, I2C, FNET, FBD-LINK, UART, SBI, Flexray and so on may be used.

The vehicle system may comprise any number of additional elements not illustrated in the example of <FIG>. Additionally, or alternatively, one or more elements of the vehicle system <NUM> illustrated in the example of <FIG> may be integrated and/or combined. For example, one or more of the vehicle systems <NUM> and the traction motor(s) <NUM> may be at least partially combined.

In some examples, one or more of the elements illustrated in the example of <FIG> may be omitted from the vehicle system <NUM>.

<FIG> illustrates an example of a method <NUM>. The method <NUM> is for controlling electrical power consumption from energy storage means <NUM> by a traction motor <NUM> of a vehicle <NUM> caused by a wheel slip event.

In examples, the vehicle <NUM> can be a vehicle <NUM> as illustrated in <FIG> and/or <NUM>.

In examples, the method <NUM> is performed by the control system <NUM> of <FIG> or <FIG> and/or as described herein or the vehicle system <NUM> of <FIG> and/or as described herein.

That is, in examples, the control system <NUM> described herein comprises means for performing the method <NUM>. However, any suitable means can be used to perform the method <NUM>.

In examples, the method <NUM> can be considered a computer implemented method <NUM>.

The method <NUM> is for controlling electrical power consumption from energy storage means <NUM> by a traction motor <NUM> of a vehicle <NUM> caused by a wheel slip event, the method <NUM> comprising:.

At block <NUM>, the method <NUM> comprises receiving a torque request <NUM> for the traction motor <NUM> of the vehicle <NUM>.

Any suitable method for receiving a torque request <NUM> for the traction motor <NUM> of the vehicle <NUM> can be used.

For example, the torque request <NUM> can be received in any suitable way.

In some examples, the control system <NUM> receives one or more signals comprising information indicative of the torque request <NUM>. For example, the control system <NUM> can receive one or more signals comprising information indicative of the torque request <NUM> from one or more of the vehicle systems <NUM> of <FIG>.

That is, in examples, the torque request <NUM> can be received by the control system <NUM> in dependence on a demand from a driver and/or virtual driver of the vehicle <NUM>.

At block <NUM>, the method <NUM> comprises determining a prevailing speed value of the traction motor <NUM>.

Any suitable method for determining a prevailing speed value of the traction motor <NUM> can be used.

In examples, the prevailing speed value of the traction motor <NUM> is received by the control system <NUM> from the traction motor <NUM>. The prevailing speed value of the traction motor <NUM> can be provided in any suitable way and/or in any suitable format. In some examples, the prevailing speed value of the traction motor <NUM> can be provided in terms of revolutions per minute (RPM).

In examples, there can be a lag in receiving the prevailing speed value of the traction motor <NUM> at the control system <NUM> compared to the actual, current, instantaneous speed value of the traction motor <NUM>.

For example, there can be a delay in the information concerning the speed value of the traction motor <NUM> reaching the control system <NUM> and therefore the actual, instantaneous speed value of the traction motor <NUM> can change during the delay period.

Accordingly, the speed value of the traction motor <NUM> received at the control system <NUM> can be considered a prevailing speed value as the actual, instantaneous speed value of the traction motor <NUM> can have changed since the received information was transmitted. It can therefore be understood that the prevailing speed value of the traction motor <NUM> has an associated latency period and that in the associated latency period the actual, instantaneous speed value of the traction motor <NUM> can change.

In examples, the latency period of the prevailing speed value of the traction motor <NUM> is approximately <NUM> to <NUM> milliseconds.

In some examples, the latency period of the prevailing speed value of the traction motor <NUM> is approximately <NUM> to <NUM> milliseconds.

In examples, the control system <NUM> comprises multiple electronic controllers <NUM>. In such examples, one or more electronic controllers <NUM> can be responsible for and/or associated with one or more actions and/or controls.

In some examples, one or more controllers <NUM>, responsible for determining available torque for a prevailing speed value of the traction motor <NUM> can be separate from the one or more controllers <NUM> responsible for controlling the traction motor <NUM>. See, for example, <FIG>.

In such examples, a delay can be introduced in providing information from the traction motor <NUM> to the controller(s) <NUM> responsible for determining available torque and passing control information to controller(s) <NUM> responsible for controlling the traction motor <NUM>.

In such examples, this can result in the prevailing speed value known by the controller(s) <NUM> responsible for determining available torque having an associated latency period.

At block <NUM>, the method <NUM> comprises determining a maximum allowable increase in speed of the traction motor <NUM> to occur during a latency period associated with the prevailing speed value of the traction motor <NUM>.

Any suitable method for determining a maximum allowable increase in the speed of the traction motor <NUM> to occur during the latency period associated with the prevailing speed value of the traction motor <NUM> can be used.

In examples, determining a maximum allowable increase in speed of the traction motor <NUM> to occur during the latency period comprises determining the increase in speed of the traction motor that is feasible during the latency period without wheel slip or including an acceptable amount of wheel slip.

That is, in examples, determining a maximum allowable increase in speed of the traction motor <NUM> to occur during the latency period comprises determining an allowable increase in speed of the traction motor <NUM> during the latency period without causing unwanted wheel slip.

The maximum allowable increase in speed of the traction motor <NUM> to occur during the latency period associated with the prevailing speed value of the traction motor <NUM> can be determined in dependence on any suitable factor or factors.

For example, mass of vehicle, mass and rotational inertia of traction motor, vehicle speed, capability of traction motor, gradient, vehicle road load such as aero losses and/or rolling losses, gear, tyres and/or tyre size and so on can be considered.

In some examples, one or more of the factors can be considered consistent and variables such as vehicle speed and gradient could be taken into account as well as a driver demand influence on the maximum expected acceleration. In some examples, only a single factor such as vehicle speed, or equivalent traction motor speed, can be taken into account.

In some examples, the maximum allowable increase in speed of the traction motor <NUM> can be determined in dependence on the prevailing speed of the vehicle <NUM>.

Accordingly, in examples, determining a maximum allowable increase in speed of the traction motor <NUM> comprises determining a prevailing speed of the vehicle <NUM> and determining the maximum allowable increase in speed of the traction motor in dependence on the prevailing speed of the vehicle <NUM>.

Any suitable method for determining a prevailing speed of the vehicle <NUM> can be used. In some examples vehicle speed is derived as the average of the wheel speed sensors. Fault handling can be used to allow, for example, use of replacement values if use of the average of the wheel speed sensors is no longer appropriate.

In some examples, the prevailing speed of the vehicle <NUM> is determined by taking an average value from the wheel speed sensors associated with each road wheel of the vehicle <NUM>. The average wheel speed may be compared with the highest and/or lowest wheel speed value from the sensors, to determine whether a wheel slip event is taking place. A further comparison may be made between signals received from wheel speed sensors and signals received from a vehicle mounted inertial measurement unit (IMU). The IMU may comprise an array of accelerometers arranged to determine the acceleration of the vehicle body in the longitudinal, vertical and lateral directions. If a sudden change in wheel speed is detected but there is no corresponding change in vehicle body acceleration, then that may be indicative of a wheel slipping.

In examples, a latency period can also exist with regard to the vehicle speed. However, in practice vehicle speed does not change quickly enough for the associated latency period to cause a significant error in the determination of the maximum allowable increase in speed of the traction motor <NUM>.

In examples, any suitable method for determining the maximum allowable increase in speed of the traction motor <NUM> in dependence on the prevailing speed of the vehicle <NUM> can be used.

For example, the prevailing speed of the vehicle <NUM> can be used as an input into one or more functions which provide, as an output, the maximum allowable increase in speed of the traction motor <NUM>.

In examples, the function can comprise any number of further inputs and/or outputs. In examples, any suitable inputs can be used in determining the maximum allowable increase in speed of the traction motor <NUM>.

In some examples, determining a maximum allowable increase in speed of the traction motor <NUM> comprises accessing at least one data structure in dependence on the prevailing speed of the vehicle <NUM>.

In such examples, the at least one data structure can comprise any suitable form or forms and can be used in any suitable way.

In some examples, the at least one data structure can take the form of and/or represent a lookup table that can be accessed in dependence on the prevailing speed of the vehicle <NUM>.

Accordingly, in examples, determining a maximum allowable increase in speed of the traction motor <NUM> comprises accessing a lookup table using the prevailing speed of the vehicle <NUM>.

In some examples, the maximum allowable increase in speed of the traction motor <NUM> can be determined in terms of a maximum change in revolutions per minute of the traction motor during the latency period associated with the prevailing speed value of the traction motor <NUM>.

In examples, the at least one function, at least one data structure, such as at least one lookup table, can be determined using any suitable method. For example, the formula and/or data structure can be determined experimentally and/or using one or more models and so on.

However, in examples any suitable latency period can be accommodated in dependence on, for example, information flow to/from the control system <NUM>.

At block <NUM>, the method <NUM> comprises determining an electrical power consumption limit <NUM> in dependence on the torque request <NUM>, the prevailing speed value of the traction motor <NUM> and the maximum allowable increase in speed of the traction motor <NUM>.

Any suitable method for determining an electrical power consumption limit <NUM> in dependence on the torque request <NUM>, the prevailing speed value of the traction motor <NUM> and the maximum allowable increase in speed of the traction motor <NUM> can be used.

In examples, determining an electrical power consumption limit <NUM> comprises determining the maximum predicted speed of the traction motor <NUM> in the latency period by adding the maximum allowable increase in speed of the traction motor <NUM> to the prevailing speed value of the traction motor <NUM> and estimating the predicted electrical power consumption of the traction motor <NUM> at that maximum allowable speed.

In examples, determining an electrical power consumption limit <NUM> comprises using one or more functions in dependence on the torque request, prevailing speed value of the traction motor <NUM> and determined maximum allowable increase in speed of the traction motor <NUM>.

For example, the torque request <NUM>, the prevailing speed value of the traction motor <NUM> and the determined maximum allowable increase in speed of the traction motor during the latency period can be used as inputs into one or more functions which provide as an output an electrical power consumption limit <NUM>.

In examples, the function can comprise any number of further inputs and/or outputs. In examples, any suitable inputs can be used in determining an electrical power consumption limit <NUM>.

In examples, determining an electrical power consumption limit <NUM> comprises accessing at least one data structure in dependence on the torque request, prevailing speed value of the traction motor and the maximum allowable increase in speed of the traction motor <NUM>.

In examples, determining an electrical power consumption limit <NUM> comprises accessing at least one data structure in dependence on the torque request <NUM> and the maximum predicted speed of the traction motor <NUM> during the latency period, the maximum predicted speed determined from the prevailing speed value of the traction motor <NUM> and the determined maximum allowable increase in speed of the traction motor <NUM> during the latency period.

The at least one data structure can represent and/or take the form of a lookup table that can be accessed in dependence of the torque request <NUM>, prevailing speed value of the traction motor <NUM> and the maximum allowable increase in speed of the traction motor <NUM>.

Accordingly, in examples, determining an electrical power consumption limit <NUM> comprises accessing a lookup table using the torque request <NUM>, prevailing speed of the traction motor <NUM> and the maximum allowable increase in speed of the traction motor <NUM>.

In examples, the at least function and/or at least one data structure for determining an electrical power consumption limit <NUM> accounts for efficiencies in provision of torque by the traction motor <NUM>.

That is, in examples, determining an electrical power consumption limit <NUM> comprises accounting for efficiencies in provision of torque by the traction motor <NUM>.

The electrical power consumption limit <NUM> can be determined in any suitable form.

In examples, the electrical power consumption limit <NUM> comprises a limit in terms of electrical current and/or power to be supplied to the traction motor.

In examples, the electrical power consumption limit <NUM> comprises a limit in terms of electrical current and/or power to be drawn from the energy storage means <NUM> by the traction motor <NUM>.

In some examples it is ensured that the electrical power consumption limit <NUM> takes into account ancillaries and/or other traction motor usage.

At block <NUM>, the method <NUM> comprises controlling torque provision of the traction motor <NUM> in dependence on the torque request <NUM> and the electrical power consumption limit <NUM>.

Any suitable method for controlling torque provision of the traction motor <NUM> in dependence on the torque request <NUM> and the electrical power consumption limit <NUM> can be used.

In examples, the traction motor <NUM> is controlled to provide the requested torque limited by the electrical power consumption limit <NUM>.

For example, the traction motor <NUM> can be controlled to provide the requested torque until the electrical power consumption limit <NUM> is reached after which the torque provided by the traction motor <NUM> is limited to prevent the electrical power consumption limit <NUM> being exceeded, such as during a wheel slip event.

In examples, controlling torque provision of the traction motor <NUM> comprises providing one or more signals comprising information to the traction motor <NUM> to control the traction motor <NUM>.

In examples, controlling torque provision comprises transmitting the torque request <NUM> and electrical power consumption limit <NUM> to control torque provision.

For example, a first controller or controllers 18a can perform blocks <NUM> to <NUM> of method <NUM> and can transmit the torque request <NUM> and electrical power consumption limit <NUM> to a further controller or controllers 18b configured to control the traction motor <NUM>. See, for example, <FIG>.

According to the invention, controlling torque provision comprises determining a speed value of the traction motor <NUM> having a lower associated latency and determining a torque limit in dependence on the lower latency speed value of the traction motor, the torque request <NUM> and the electrical power consumption limit <NUM>.

For example, when the torque request <NUM> and electrical power consumption limit <NUM> are transmitted from a first controller or controllers 18a to a different controller or controllers 18b to control the traction motor <NUM> the further or different controller or controllers 18b may have access to a speed value of the traction motor <NUM> having a lower associated latency.

For example, the different or second controller or controllers 18b may be closer to the traction motor <NUM> and therefore the speed of the traction motor <NUM> may be determined at the different or second controller or controllers <NUM> with less lag or a lower latency period.

In such examples, the different or second controller or controllers 18b can determine a speed value of the traction motor <NUM> having a lower associated latency and determine a torque limit, for torque to be provided by the traction motor <NUM>, in dependence on the lower latency speed value of the traction motor <NUM>, the torque request <NUM> and the electrical power consumption limit <NUM>.

In examples, determining a torque limit comprises using a model of the electrical power to torque conversion of the traction motor <NUM> to calculate the torque limit using the value of speed of the traction motor having the lower associated latency.

Any suitable model can be used. In some examples, the torque limit can be applied directly in current and in such examples no conversion of the limit is performed.

The control system <NUM> can limit the requested torque using the determined torque limit if the electrical power consumption limit <NUM> will be exceeded, such as during a wheel slip event.

A technical effect of the method <NUM> is that a limit can be placed on electrical power consumption preventing traction battery damage and/or use of intrusive battery protection features when a wheel slip event occurs.

Additionally, or alternatively, in some examples, closed loop control is provided within a single controller which obviates issues with network latency.

<FIG> illustrates an example of a control system. The control system <NUM> of <FIG> can be as described in relation to <FIG> and/or <FIG>.

In examples, the control system <NUM> of <FIG> is configured to perform the method of <FIG> and/or as described herein.

In the example of <FIG>, the control system <NUM> comprises two controllers 18a, 18b. However, in some examples the control system can comprise any suitable number of controllers <NUM>.

In the example of <FIG>, the first and second controllers 18a, 18b are configured to perform different parts of the method <NUM>. Accordingly, it can be considered, in examples, that in the example of <FIG> the first and second controllers 18a, 18b are responsible for different parts of the method <NUM>.

In the example of <FIG>, information can flow to and from the first and second controllers 18a and 18b and between the first and second controllers 18a and 18b as illustrated by the double headed arrows in <FIG>.

In the example of <FIG>, the first controller 18a is configured to perform, at least, blocks <NUM> to <NUM> of the method <NUM> of <FIG>.

However, in the example of <FIG>, controller 18b is configured to perform, at least, block <NUM> and is therefore configured to control provision of torque by the traction motor or motors <NUM>. In some examples, the controller(s) 18b can be an inverter.

Accordingly, the first controller 18a has a prevailing speed value of the traction motor <NUM> having a larger associated latency period than the second controller 18b which is closer to the traction motor <NUM>.

Therefore, in the example of <FIG>, the controller 18a, configured to perform blocks <NUM> to <NUM> of <FIG> and provide the control information to controller 18b to control torque provision from the traction motor <NUM> can do so while implementing closed loop control at the controller 18b despite the latency period associated with the speed value of the traction motor <NUM> accessible at the controller 18a.

It can be seen, therefore, in the example of <FIG> that by using the inventive method <NUM> described herein power spikes from a traction battery can be avoided during a wheel slip event.

This is because an electrical power consumption limit <NUM> is used to limit the torque provided to prevent excessive power being drawn from a traction battery due to a wheel accelerating quickly during a latency period of the speed value of the traction motor <NUM> known by controller 18a.

<FIG> illustrates an example of controlling electrical power consumption from energy storage means <NUM> by a traction motor <NUM> of a vehicle <NUM> caused by a wheel slip event.

In examples, the vehicle <NUM> is the vehicle illustrated in <FIG> or <FIG>.

The example of <FIG> is split into three sections, an upper section A, a middle section B. and a lower section C.

The upper section of <FIG> can therefore be considered <FIG>, the middle section of <FIG> can be considered <FIG> and the lower section of <FIG> can be considered <FIG>.

<FIG> illustrates traction motor current as a function of time.

<FIG> illustrates traction motor speed as a function of time.

<FIG> illustrates traction motor torque as a function of time.

Also illustrated in <FIG> are four times t1, t2, t3 and t4 which are common to <FIG>.

In <FIG>, a torque request for the traction motor <NUM> is illustrated by dashed line <NUM>. It can be seen In <FIG> that the torque request is constant up until time t2.

In <FIG> the traction motor current without use of the inventive method described herein is illustrated by the solid line <NUM>.

Before time t1 the current <NUM> drawn by the traction motor <NUM> increases in line with the increasing speed of the traction motor <NUM> due to the torque request <NUM>.

However, at time t1 there is a wheel slip event and the speed of the traction motor <NUM> increases rapidly as illustrated by the solid line <NUM> in <FIG>.

It can be seen that between times t1 and t2 the current <NUM> drawn by the traction motor <NUM> increases rapidly and passes above the battery discharge current limit illustrated by the solid horizontal line labelled <NUM>.

Accordingly, without the inventive method described herein, repeated exposure to events such as these may lead to battery damage.

In the example of <FIG>, at time t2, implausible wheel acceleration is determined and therefore the torque request <NUM> is limited. This can be seen in <FIG> by the torque request <NUM> reducing between times t2 and t3.

Accordingly, the current <NUM> drawn by the traction motor <NUM> also reduces between times t2 and t3 passing below the battery discharge current limit <NUM> around time t3.

The corresponding speed <NUM> of the traction motor <NUM> also reduces during times t2 and t3.

At time t3 the wheel slipping event is detected by a system of the vehicle <NUM>, such as a stop control system, and further torque intervention <NUM> is then applied.

This can be seen in <FIG> as between times t3 and t4 the torque request <NUM> is further limited and, in <FIG> the current <NUM> by the traction motor <NUM> also further reduces.

Similarly, in <FIG>, the corresponding speed <NUM> of the traction motor <NUM> also continues to reduce between times t3 and t4.

The torque provided by the traction motor <NUM> in this example is illustrated in <FIG> by the solid line labelled <NUM>. The torque provided <NUM> without the method described herein follows the torque request <NUM>.

It can be therefore seen in the example of <FIG> that a wheel slip event can, without the inventive method described herein, can lead to unnecessarily large power drawn from a traction battery, for example.

Also illustrated in the example of <FIG> is an example of applying the inventive electrical power consumption control described herein.

In this example, the torque request <NUM> in <FIG> remains the same. The current drawn in this case is illustrated by the dot-dashed line <NUM> and it can be seen that prior to time t1 the current <NUM> matches the current <NUM> drawn without using the method described herein. However, in the example of <FIG> the lines <NUM> and <NUM> have been offset slightly for the purpose of illustration.

At time t1 the current <NUM> drawn while using the method described herein also increases after the wheel slip event but is limited by the electrical consumption power limit <NUM> shown as a dashed line in <FIG>.

It can therefore be seen that the electrical current drawn <NUM> rises sharply but then is prevented from exceeding the electrical consumption power limit <NUM>. This also, therefore, prevents the battery discharge current limit <NUM> from being exceeded.

The corresponding traction motor speed is illustrated in <FIG> by the dot-dashed line <NUM>. It can be seen that the speed <NUM> of the traction motor <NUM> does not increase as much as the speed <NUM> without the method described herein.

The current <NUM> drawn by the traction motor <NUM> continues to follow the electrical consumption power limit <NUM> until time t3 in which intervention <NUM> further limits the torque provided.

The associated torque provided by the traction motor <NUM> is shown by the dot-dashed line <NUM> in <FIG>.

It can be seen in <FIG> that, for the example using the method described herein, the torque provided by the traction motor <NUM>, compared to the torque requested, is limited between times t1 and t3 compared to the case (line <NUM> in <FIG>) where the inventive method described herein is not used. This is illustrated by the hashed area in <FIG>.

As used herein "for" should be considered to also include "configured or arranged to". For example, "a control system for" should be considered to also include "a control system configured or arranged to".

For purposes of this disclosure, it is to be understood that the controller(s) described herein can each comprise a control unit or computational device having one or more electronic processors. A vehicle 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.

The blocks illustrated in the <FIG> may represent steps in a method and/or sections of code in the computer program <NUM>. 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.

Claim 1:
A control system (<NUM>) for controlling electrical power consumption from energy storage means (<NUM>) by a traction motor (<NUM>) of a vehicle (<NUM>) caused by a wheel slip event, the control system (<NUM>) comprising one or more electronic controllers (<NUM>), the one or more electronic controllers (<NUM>) configured to:
receive a torque request (<NUM>) for the traction motor (<NUM>);
determine a prevailing speed value of the traction motor (<NUM>);
determine a maximum allowable increase in speed of the traction motor (<NUM>) to occur during a latency period associated with the prevailing speed value of the traction motor (<NUM>); wherein the latency period is defined as the delay period between the actual, instantaneous speed value of the motor (<NUM>) and the determined prevailing speed value of the motor (<NUM>);
determine an electrical power consumption limit (<NUM>) in dependence on the torque request (<NUM>), the prevailing speed value of the traction motor (<NUM>) and the maximum allowable increase in speed of the traction motor (<NUM>); and
control torque provision of the traction motor (<NUM>) in dependence on the torque request (<NUM>) and the electrical power consumption limit (<NUM>); wherein control of the torque provision comprises determining a speed value of the traction motor (<NUM>) having a lower associated latency and determining a torque limit in dependence on the lower latency speed value of the traction motor (<NUM>), the torque request (<NUM>) and the electrical power consumption limit (<NUM>).