US 20140100726A1
`a9 United States
`
`a2 Patent Application Publication (o) Pub. No.: US 2014/0100726 A1
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`Reynolds et al. (43) Pub. Date: Apr. 10, 2014
`(54) CONTROL STRATEGY FOR AN ELECTRIC Publication Classification
`MACHINE IN A VEHICLE
`(51) Int.ClL
`(71) Applicant: FORD GLOBAL TECHNOLOGIES, GOGF 17/00 (2006.01)
`LLC, Dearborn, MI (US) B6OW 10/08 (2006.01)
`B6OW 20/00 (2006.01)
`(72) Inventors: William Reynolds, Tecumseh (CA); B6OW 10/06 (2006.01)
`Daniel Robert Parks, Novi, MI (US); (52) US.CL
`Rimma Isayeva, Farmington Hills, MI USPC oo 701/22; 903/930
`(US); Jonathan Andrew Butcher, )
`Farmington, MI (US) (57) ABSTRACT
`A vehicle is provided including an electric machine and at
`(73) Assignee: FORD GLOBAL TECHNOLOGIES, least one controller. The controller, or controllers, are config-
`LLC, Dearborn, MI (US) ured to, in response to a reset of the at least one controller
`
`while a speed of the vehicle is greater than a threshold value,
`provide a current command to the electric machine in accor-
`dance with calibration values calculated prior to the reset such
`that inoperability of the electric machine due to the reset is
`(22) Filed: Oct. 5,2012 less than one second.
`
`(21) Appl. No.: 13/646,210
`
`10 TRANSMISSION
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`20 COMBUSTION
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`INVERTER SYSTEM
`CONTROL MODULE
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`34 -
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`Patent Application Publication
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`Toyota v. Bunker Hill IPR2026-00333
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`Apr. 10,2014 Sheet 2 of 4
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`’/\/
`
`NO
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`YES €
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`106
`CURRENT SENSOR
`
`OFFSET VALUES
`RECEIVED FROM
`
`108
`
`YES
`ENTER SENSOR
`
`14— READING INTO ‘ZERO
`CURRENT SENSOR’
`ALGORITHM
`
`NUMBER OF
`READINGS >
`116 MIN SAMPLES?
`
`Y
`
`CALCULATE CURRENT
`
`UPDATE CURRENT
`SENSOR OFFSETS
`
`118—"| USING VALUES READ SENSOR OFFSETS | 110
`FROM CURRENT USING VALUES READ
`
`-
`
`Y
`
`SET EACH DEVICE
`112—"| FLAG TO ‘ZEROING
`COMPLETE
`
`Y
`
`- FIG. 3
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`Apr. 10,2014 Sheet 4 of 4
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`( START )} 202
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`/
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`SET FLAG TO
`
`COMPLETE = FALSE
`
`CALIBRATION SEQUENCE
`
`HAS MGCU
`GONE THROUGH
`A RESET?
`
`YES 204
`
`YES
`
`HAS A
`CALIBRATION
`COMMAND BEEN
`SUCCESSFULLY
`SENT?
`
`208
`
`210
`
`SEND STORED CURRENT SENSOR
`OFFSET VALUES AS LAST
`RECEIVED FROM THE MGCU
`
`/
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`STORE CURRENT OFFSET
`VALUES TO MEMORY
`
`212
`214
`
`/
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`CHECK STATUS OF CURRENT SENSOR
`ZEROING WITHIN THE MGCU
`
`216
`
`MGCU
`COMPLETE ZEROING
`FOR MOTOR
`GENERATOR,
`AND VVC?
`
`SET FLAG TO CALIBRATION
`SEQUENCE COMPLETE = TRUE
`
`FIG. 4
`
`i
`END
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`CONTROL STRATEGY FOR AN ELECTRIC
`MACHINE IN A VEHICLE
`
`TECHNICAL FIELD
`
`[0001] The present disclosure relates to a system for con-
`trolling an electric machine in an electric vehicle.
`
`BACKGROUND
`
`[0002] Battery electric vehicles (BEVs) include a traction
`battery that is rechargeable from an external electric power
`source and powers the electric machine. Hybrid electric
`vehicles (HEVs) include an internal combustion engine, one
`or more electric machines, and a traction battery that at least
`partially powers the electric machine. Plug-in hybrid electric
`vehicles (PHEVS) are similar to HEVs, but the traction bat-
`tery in a PHEV is capable of recharging from an external
`electric power source. These vehicles are examples of
`vehicles that are capable of being at least partially driven by
`an electric machine.
`
`[0003] These vehicles often rely on a network of microcon-
`trollers to perform an array of tasks related to powertrain
`operation. Although internal microprocessors are generally
`reliable, they are not infallible. It is possible to have intermit-
`tent, and/or irreproducible issues that lead to an internal reset
`of a given controller. Internal microprocessor resets can have
`multiple causes. A reset can result in lost communication
`between the reset controller and other modules. Such a failed
`communication can disable the vehicle from continued
`operation. A failure of this sort while the vehicle is in motion,
`also referred to as a rolling reset, can greatly impact customer
`satisfaction. A strategy for a rapid recovery while the vehicle
`remains in a motive state is desirable.
`
`SUMMARY
`
`[0004] In at least one embodiment, a vehicle is provided
`comprising an electric machine and at least one controller.
`The controller(s) is configured to, in response to a reset of the
`at least one controller while a speed of the vehicle is greater
`than a threshold value, provide a current command to the
`electric machine in accordance with calibration values calcu-
`lated prior to the reset such that inoperability of the electric
`machine due to the reset is less than one second.
`
`[0005] In at least one embodiment, a vehicle powertrain
`control system is provided comprising an electric machine, a
`first controller configured to supply a torque command, and a
`second controller configured to generate a calibration value
`and to provide a current command to the electrical machine.
`The current command is further based on the torque com-
`mand and the calibration value. Additionally, the first control-
`ler stores the calibration value and further provides the cali-
`bration value to the second controller in response to a reset of
`the second controller while a speed of the vehicle is greater
`than a threshold value. The response of the first controller is
`such that inoperability of the electric machine due to the reset
`is less than one second.
`
`[0006] Inatleast one embodiment, a method for controlling
`torque actuation of a hybrid-electric vehicle is provided. The
`method comprises generating a current command signal
`based on a torque request, generating a calibration value
`indicative of a current command adjustment offset, and send-
`ing a signal to a first controller indicative of the calibration
`value. The method further comprises storing the calibration
`value in a memory of the first controller, providing the cali-
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`Apr. 10, 2014
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`bration value to a second controller in response to a reset of
`the second controller while a speed of the vehicle is above a
`threshold, and resuming operation of the second controller
`using the calibration value such that a period of inoperability
`of an electric machine propelling the vehicle is less than one
`second.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`[0007] FIG. 1 is a schematic diagram of a vehicle power-
`train;
`[0008] FIG. 2 is a system block diagram illustrating an
`
`example of a powertrain control system of the vehicle;
`[0009] FIG. 3 is a flow chart of an algorithm implemented
`in the control system of the vehicle; and
`
`[0010] FIG. 4 is a flow chart of an algorithm implemented
`in the control system of the vehicle.
`
`DETAILED DESCRIPTION
`
`[0011] Embodiments of the present disclosure are
`described herein. It is to be understood, however, that the
`disclosed embodiments are merely examples and other
`embodiments can take various and alternative forms. The
`figures are not necessarily to scale; some features could be
`exaggerated or minimized to show details of particular com-
`ponents. Therefore, specific structural and functional details
`disclosed herein are not to be interpreted as limiting, but
`merely as a representative basis for teaching one skilled in the
`art to variously employ the present invention. As those of
`ordinary skill in the art will understand, various features
`illustrated and described with reference to any one of the
`figures can be combined with features illustrated in one or
`more other figures to produce embodiments that are not
`explicitly illustrated or described. The combinations of fea-
`tures illustrated provide representative embodiments for typi-
`cal applications. Various combinations and modifications of
`the features consistent with the teachings of this disclosure,
`however, could be desired for particular applications or
`implementations.
`
`[0012] A schematic diagram of a powertrain system of a
`hybrid-electric vehicle 10 according to the present disclosure
`is illustrated in FIG. 1. The claimed invention may however,
`be applied to other powertrain topology. Internal combustion
`engine 20 drives carrier 22 of planetary gear set 24. The
`engine torque is divided by gear set 24 between sun gear 26
`and ring gear 28. The ring gear torque is mechanically trans-
`mitted to output shaft 30. The sun gear torque is absorbed by
`an electric generator 32 in connection with the sun gear 26. An
`electric traction motor 34 is also driveably connected to out-
`put shaft 30. Throughout this description, the terms generator
`and motor are used merely as labels to identify these compo-
`nents. Both the generator 32 and the motor 34 are reversible
`electric machines capable of both converting mechanical
`shaft power into electrical power, and converting electrical
`power into mechanical shaft power. The driveshaft is drive-
`ably connected to a differential 38 which divides the power
`between wheels 40 while accommodating some differences
`in wheel speeds.
`
`[0013] Still referring to FIG. 1, generator 32 and motor 34
`are electrically powered through inverters 42 and 44 respec-
`tively via three-phase power circuits. Electrical power con-
`nections are illustrated by dashed lines with long dashes.
`Inverters 42 and 44 draw power from or supply powerto a DC
`electrical bus 50. Electrical power stored in battery 46 is sent
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`through a DC-DC voltage converter to modify the vehicle
`voltage level according to the devices being powered. The
`variable voltage control (VVC) 48 converts the DC voltage
`level of battery 46 to the DC desired voltage level of high-
`voltage electrical bus 50.
`
`[0014] The generator 32 and motor 34 can both be referred
`to as electric machines. Each electric machine can operate as
`a generator by receiving torque from the engine 20 and sup-
`plying AC voltage to an inverter. Alternatively, the electric
`machine can operate as a motor whereby the electric machine
`receives power from the battery 46 via the inverter and pro-
`vides an assistive torque actuation through the transmission to
`the wheels.
`
`[0015] The vehicle 10 may be powered by the engine 20
`and the generator 32, by the battery 46 and motor 34 alone, or
`by a combination of the engine 20 with the battery 46 and
`motor 34. In a mechanical drive mode, or a first mode of
`operation, the engine 20 is activated to deliver torque through
`the planetary gear set 24 as described above. In the mechani-
`cal drive mode, the motor 34 may also be activated to assist
`the engine 20 in powering the transmission.
`
`[0016] It should be understood that while a power-split
`powertrain is illustrated in the vehicle 10, the vehicle 10 can
`include many other configurations. As such, it is contem-
`plated that individual components of the powertrain may
`differ to suit various particular applications. For example, in
`another configuration that does not include a planetary gear
`set 24, an electric machine (motor/generator) can be provided
`to operate as a generator by receiving torque from the engine
`or regenerative braking, while the same electric machine can
`also operate as a motor by receiving power from the traction
`battery and providing torque through the transmission. Other
`vehicle configurations of vehicle powertrains and implemen-
`tations of electric machines are contemplated, and are there-
`fore considered to be within the scope of the present disclo-
`sure.
`
`[0017] The battery 46 further includes a two-way electrical
`connection, such that it can also receive and store energy
`provided through regenerative braking, for example, and then
`supply the energy to an electric machine. Electrical energy
`that is generated from torque absorbed by the generator 32
`can be transferred to the battery 46 through electrical connec-
`tions. The battery 46 supplies stored energy to the motor 34
`for operation. The motor 34 can use the energy to provide an
`assistive torque actuation to the engine 20. A portion of the
`power delivered from the engine 20 to the generator 32 may
`also be transmitted directly to the motor 34.
`
`[0018] A hybrid powertrain control module (HPCM) 52
`issues control signals to the VVC 48 specifying the desired
`voltage for the DC electrical bus 50. Control signal connec-
`tions are illustrated by dashed lines with short dashes. The
`HPCM 52 also senses voltage levels of both the battery 46 the
`output voltage of the VVC 48. In response to a driver input,
`the HPCM 52 issues control command signals to engine 20
`and inverters 42 and 44 to regulate the aggregate torque
`generated by the combination of the engine 20, generator 32,
`and motor 34. The HPCM 52 further senses the actual output
`of inverters 42 and 44. If the torque actually delivered by
`motor 34 differs significantly from the requested torque, then
`vehicle acceleration will not match the driver’s expectation. If
`the torque actually delivered by generator 32 differs signifi-
`cantly from the requested torque, then engine speed will
`depart from expected behavior.
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`Apr. 10, 2014
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`[0019] Although the vehicle powertrain system 10 is illus-
`trated to have a HPCM, such a control system can include
`more or less than two controllers, as desired. For example, a
`separate battery control module (BCM) can directly control
`the battery 46. Furthermore, a separate motor control module
`can be directly connected to the motor 34 and to the other
`controllers in the vehicle. It should be understood that all
`contemplated propulsion controllers in the vehicle are each
`characterized in the HPCM embodiment.
`
`[0020] Electrical energy generated by generator 32 can be
`provided in the form of three-phase alternating currents.
`Similarly, the load of the traction motor 34 may also be
`three-phase analog alternating current. The HPCM 52 senses
`outputs of both the generator 32 and motor 34 as analog
`signals. Other sensed values are also received by the HPCM
`52 in analog form. For example, the DC bus 50 voltage, the
`battery 46 voltage, additional vehicle on-board voltages, and
`a plurality of temperature sensors may all be monitored by the
`HPCM 52. The analog signals indicative of vehicle operating
`conditions can be converted to digital signals for processing
`by microcontrollers within the HPCM 52. Microcontrollers
`are often equipped with a limited number of analog to digital
`converters (ADC’s). Additionally, command signals for the
`motor and generator are generated in a digital form from the
`HPCM 52. In order to control the motor 34, the generator 32
`and the VVC 48, the ADC’s must be ready to convert the
`sensed analog current signals associated with each of the
`motor and generator, as well as sensed voltage associated
`with the VVC 48. In response to the monitored values, the
`HPCM 52 issues command signals to the motor inverter 44,
`the generator inverter 42 and the VVC 48 all at a predeter-
`mined cadence. The plurality of required conversions and
`data acquisitions may all be managed using a single micro-
`controller.
`
`[0021] Referring to FIG. 2, a block diagram illustrating an
`embodiment of a powertrain control system 62 within the
`vehicle 10 is shown. A driver inputs a request 64, such as by
`pressing the accelerator to input an acceleration request. The
`driver requests 64 are received by an engine control module/
`vehicle system controller, or ECM/VSC 66. The ECM/VSC
`66 processes these driver requests 64 and communicates com-
`mands throughout the vehicle 10. The ECM/VSC 66 is elec-
`trically connected to various subsystems in the vehicle 10 and
`acts as an overall control of the vehicle 10. For example, the
`ECM/VSC 66 is connected to the hybrid HPCM 52 that
`controls the hybrid-specific components in the vehicle 10,
`such as the motor 78, the generator 80, the VVC 48, and/or the
`battery 46.
`
`[0022] The HPCM 52 can include a combination of internal
`microcontrollers having different functions. In at least one
`embodiment, a dedicated hybrid control unit (HCU) 68 is
`included to receive torque commands from the ECM/VSC 66
`via a vehicle CAN BUS 70. The HPCM 52 further includes a
`motor/generator control unit (MGCU) 72. The HCU 68 is
`communicatively connected to the MGCU 72 via a serial
`peripheral interface (SPI) 74 link. The HCU 68 provides
`torque request signals to the MGCU 72 through the SP174. In
`response, the MGCU 72 provides current command signals to
`an inverter system 76 that regulates current provided to each
`of the motor 78 and generator 80. The command signals can
`comprise modulated pulse widths, or PWM, in order to
`employ digital control logic to create an analog equivalence.
`The inverter system 76 further regulates the VVC 82 to cause
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`an adjustment in the voltage supplied between the vehicle
`battery and each of the motor 78 and generator 80.
`
`[0023] The HPCM 52 can also be communicatively con-
`nected to other control units such as an engine control unit, or
`ECU, such that the HCU 68 commands the ECU to control the
`engine 20 in various manners. In another embodiment, a
`separate control unit is provided for each of the motor 78 and
`the generator 80. Further, a battery control module (BCM)
`may also be included to receive commands from the HCU 68
`and control the power distribution of the 46 battery. As illus-
`trated in FIG. 2, motor inverter 84 and generator inverter 86
`are controlled by, and communicatively connected to the
`MGCU 72. The motor inverter 84 and generator inverter 86
`receive commands from the MGCU 72, and open and close
`internal switches to enable and disable power flow to and
`from the electric machines.
`
`[0024] The VVC 82 is also communicatively connected to
`and controlled by the MGCU 72. The MGCU 72 controls the
`inductor 88 such that the VVC 82 modifies voltage supplied to
`both of the motor 78 and generator 80. Specifically, the VVC
`82 is used to boost the battery 46 voltage to a higher level
`voltage in a HEV drivetrain system for multi-purposes such
`as, but not limited to, torque capability optimizations for
`electric machines, system loss optimization, and so on.
`[0025] Although a hierarchy of controllers is thus provided
`in the illustration shown in FIG. 2, other hierarchies of con-
`trollers are contemplated without deviating from the scope of
`the present disclosure. For example, the ECM/VSC 66 may
`directly communicate with the MGCU 72 without the pres-
`ence of an HCU 68. Other configurations are contemplated
`that would be beneficial for different particular vehicles. The
`ECM/VSC 66 controls each of the servient controllers,
`according to requested torque and power demands. More or
`less controllers than those described herein are contemplated,
`and one or more of these controllers can communicatively
`cooperate to accomplish certain tasks. Any and all of these
`controllers or combination thereof can simply be referred to
`as a “controller”.
`
`[0026] Related to the required precision of provided elec-
`tric current levels, the vehicle can be configured to undergo
`schedule calibration procedures upon a power up. In at least
`one embodiment, a plurality of current sensors are zeroed
`such that offset values are added to sensor readings to account
`for trace current present in the electric system, vehicle exter-
`nal conditions affecting current readings, or other sources of
`sensor drift. Each of the three-phase source current connec-
`tions for both the motor and the generator undergo a zeroing
`process on vehicle startup. As a result of this process, the
`MGCU 72 generates calibration values, or current sensor
`offsets, which are associated with each of the source current
`connections. The MGCU 72 in turn generates current com-
`mands which are adjusted based on the current sensor offset
`values. Additionally, the VVC 82 undergoes a similar self-test
`scheduled to occur at power up events. In further embodi-
`ments, a plurality of diagnostic signal assessments may be
`conducted to verify the integrity of the electrical system. For
`example, a pulse test performed precedent to providing cur-
`rent commands can be used to verify high voltage connectiv-
`ity throughout the system.
`
`[0027] The MGCU 72 is generally configured to undergo
`scheduled power up procedures after a reset. However, sensor
`calibration while active current is flowing through the elec-
`trical network would be ineffective, and further may disable
`the powertrain. In at least one embodiment, a recovery strat-
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`Apr. 10, 2014
`
`egy is included for the HPCM 52 to rapidly recover from a
`rolling reset event. This prevents complete shutdown of the
`vehicle 10, which can be undesirable to drivers. The MGCU
`72 is configured to provide the calibration values to the HCU
`68 after each determination. The HCU 68 stores the values in
`a memory. The HCU 68 is configured to sense the cause of a
`reset. For example, the HCU 68 can recognize an internal
`controller reset versus a customer-induced reset. In response
`to sensing an internal reset of the MGCU 72 while the vehicle
`is above a predetermined speed threshold, the HCU 68 pro-
`vides the previously stored calibration values to the MCGU
`72. In this way, the MCGU 72 is configured to bypass prede-
`termined power up procedures and accept stored values that
`are provided from the HCU 68. The MCGU 72 in turn
`resumes operation in accordance with the calibration values
`identified prior to the reset. This strategy allows for inoper-
`ability of the electric machine as a result of a reset of the
`MGCU 72 during vehicle movement to be minimized. Ide-
`ally, the effect of the rolling reset is imperceptible to a driver
`and torque commands are supplied in a substantially imme-
`diate fashion. For example, in at least one embodiment the
`electric machine has a period of inoperability in the general
`range of 200 to 300 milliseconds following a reset.
`
`[0028] FIG. 3 depicts a flow chart of a controller recovery
`method, generally indicated by reference numeral 100. The
`algorithm shows the recovery process of a slave controller, for
`example the MGCU, after a rolling reset. The algorithm ini-
`tiates at step 102. The controller is configured to make assess-
`ments at time interval T1. Therefore if the elapsed time is
`greater than T1 at step 104, the controller proceeds to the next
`step and considers the vehicle speed. Ifthe elapsed time is less
`than T1 at step 104, the controller holds until the elapsed time
`reaches T1.
`
`[0029] The controller senses vehicle speed at step 106. If
`the vehicle speed is above a threshold, indicated by Speed-
`maxzero» then the controller does not attempt to recalibrate
`current sensors to obtain new offset values. The maximum
`speed threshold may be set to a sensed value of the rotation of
`the motor resolver at, for example, 10 rpm. The threshold can
`be set to low value to ensure that the speed is sufficiently low
`before attempting a current sensor calibration. The controller
`then advances to step 108 to assess whether current sensor
`offset values have been provided by the HCU. If no offset
`values have been received, the controller returns to step 106 to
`reassess vehicle speed. This loop would continue with the
`MGCU disabled until either offsets were provided by the
`HCU, or the vehicle speed was low enough to perform a
`zeroing calibration of the current sensors.
`
`[0030] Ifthe current offset values have been received from
`the HCU at step 108, the controller updates current sensor
`offset values at step 110 using those values provided by the
`HCU. The controller proceeds to step 112 and sets an internal
`flag to “zeroing complete” for each device that corresponding
`offset values were received. This flag provides an indication
`to the master controller HCU that the MGCU is ready to
`provide current commands to each of the motor and genera-
`tor, and/or voltage commands to the VVC.
`
`[0031] Ifthe vehicle speed is below the threshold, indicated
`by Speed, . xzrro» at step 106 then the controller enters a
`process to zero the current sensors. The controller takes cur-
`rent readings at step 114 for each of the sensors to be cali-
`brated. The mode includes collecting an adequate number of
`sample readings to generate current offset values with a con-
`fidence of no false readings or anomalies. The controller
`
`Petitioner EX1010
`Toyota v. Bunker Hill IPR2026-00333
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`8 of 10
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`US 2014/0100726 Al
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`assesses at step 116 whether the required minimum number
`of sample current sensor readings has been supplied in order
`for the calculation algorithm to determine new offset values.
`If less than the required number of readings has been
`acquired, the controller returns to step 106 to reassess vehicle
`speed to ensure it is appropriate to continue gathering more
`calibration readings.
`
`[0032] If at step 116 the required number of readings has
`been acquired, the controller calculates at step 118 new cur-
`rent sensor offset values based on the readings. The controller
`proceeds to step 112 and sets an internal flag to “zeroing
`complete” for each device that corresponding offset values
`were received. Again, this flag notifies the HCU that the
`MGCU is in an operational state to provide appropriate cur-
`rent commands to the electric machine.
`
`[0033] FIG. 4 depicts a recovery method flowchart accord-
`ing to a master controller, for example the HCU, which is
`indicated generally by reference numeral 200. The controller
`begins the recovery procedure at step 202. The controller first
`determines at step 204 whether the slave controller, for
`example the MGCU, has undergone a reset. If the slave con-
`troller has gone through a reset at step 204, the master con-
`troller sets an internal calibration sequence complete flag to
`“false” in step 206, indicating that sensor calibration is
`required. The controller assesses at step 208 whether a prior
`successful sensor calibration command has been sent to the
`slave controller. If a prior command has been sent, the recov-
`ery sequence 200 is complete from the perspective of the
`master controller.
`
`[0034] If at step 208 no prior successful calibration
`sequence is indicated, the master controller sends previously
`stored current sensor offset values to the slave controller.
`These values may have been stored to memory upon receipt
`from a prior calculation performed by the slave controller.
`The controller then stores the current offset values to memory
`as up to date values. The values may carry a new time stamp.
`[0035] The master controller then checks the status of cur-
`rent sensor zeroing of the slave controller at step 214. The
`master controller assesses the zeroing status at step 216. If the
`zeroing is complete within the slave controller at step 216, the
`master controller sets the calibration sequence complete flag
`to “true” in step 218. This flag can serve to indicate that a
`calibration sequence is no longer required, and authorize
`further torque commands. If the current sensor zeroing is not
`complete at step 216, the master controller returns to step 204
`to re-attempt the recovery sequence.
`
`[0036] In the above embodiments, the master controller
`recognizes a reset of the slave controller, and in response,
`provides sensor calibration values. It is contemplated that
`alternative embodiments may include the slave controller
`providing an active request to the master controller for pre-
`viously stored current sensor offset values in response to a
`reset.
`
`[0037] The processes, methods, or algorithms disclosed
`herein can be deliverable to/implemented by a processing
`device, controller, or computer, which can include any exist-
`ing programmable electronic control unit or dedicated elec-
`tronic control unit. Similarly, the processes, methods, or algo-
`rithms can be stored as data and instructions executable by a
`controller or computer in many forms including, but not lim-
`ited to, information permanently stored on non-writable stor-
`age media such as ROM devices and information alterably
`stored on writeable storage media such as floppy disks, mag-
`netic tapes, CDs, RAM devices, and other magnetic and opti-
`
`Apr. 10, 2014
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`cal media. The processes, methods, or algorithms can also be
`implemented in a software executable object. Alternatively,
`the processes, methods, or algorithms can be embodied in
`whole or in part using suitable hardware components, such as
`Application Specific Integrated Circuits (ASICs), Field-Pro-
`grammable Gate Arrays (FPGAs), state machines, controllers
`or other hardware components or devices, or acombination of
`hardware, software and firmware components.
`
`[0038] While exemplary embodiments are described
`above, it is not intended that these embodiments describe all
`possible forms encompassed by the claims. The words used in
`the specification are words of description rather than limita-
`tion, and it is understood that various changes can be made
`without departing from the spirit and scope of the disclosure.
`As previously described, the features of various embodiments
`can be combined to form further embodiments of the inven-
`tion that may not be explicitly described or illustrated. While
`various embodiments could have been described as providing
`advantages or being preferred over other embodiments or
`prior art implementations with respect to one or more desired
`characteristics, those of ordinary skill in the art recognize that
`one or more features or characteristics can be compromised to
`achieve desired overall system attributes, which depend on
`the specific application and implementation. These attributes
`can include, but are not limited to cost, strength, durability,
`life cycle cost, marketability, appearance, packaging, size,
`serviceability, weight, manufacturability, ease of assembly,
`etc. As such, embodiments described as less desirable than
`other embodiments or prior art implementations with respect
`to one or more characteristics are not outside the scope of the
`disclosure and can be desirable for particular applications.
`
`What is claimed is:
`
`1. A vehicle comprising:
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`an electric machine; and
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`at least one controller configured to, in response to a reset
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`of the at least one controller while a speed of the vehicle
`is greater than a threshold value, provide a current com-
`mand to the electric machine in accordance with cali-
`bration values calculated prior to the reset such that
`inoperability of the electric machine due to the reset is
`less than one second.
`
`2. The vehicle of claim 1 wherein the at least one controller
`is further configured to, in response to a reset of the at least
`one controller while a speed of the vehicle is greater than a
`threshold value, provide a current command to the electric
`machine in accordance with calibration values identified
`prior to the reset such that inoperability of the electric
`machine due to the reset is less than 300 milliseconds.
`
`3. The vehicle of claim 1 wherein the at least one controller
`is further configured to, after the reset, request calibration
`values from a master controller.
`
`4. The vehicle of claim 1 wherein the calibration values are
`indicative of at least one electric machine source current
`offset value corresponding to an adjustment of the current
`command.
`
`5. The vehicle of claim 1 wherein the at least one controller
`is further configured to perform a predetermined power up
`procedure and to calculate new calibration values once the
`vehicle is restarted following a power down and the speed of
`the vehicle is less than threshold value.
`
`6. The vehicle of claim 5 wherein the predetermined power
`up procedure includes a diagnostic signal assessment prece-
`dent providing a current command to the electric machine.
`
`Petitioner EX1010
`Toyota v. Bunker Hill IPR2026-00333
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`9 of 10
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`US 2014/0100726 Al
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`7. The vehicle of claim 1