Active battery system estimation request generation

• US 9,272,634 B2
• Filed: 02/20/2014
• Issued: 03/01/2016
• Est. Priority Date: 02/20/2014
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Li, Yonghua, Yu, Hai
• Primary Examiner(s): Khatib, Rami
• Assistant Examiner(s): BOOMER, JEFFREY C
• Application Number:
  US14/184,939
• Publication Number:
  US 20150231982A1
• Time in Patent Office: 740 Days
• US Class Current: 1/1
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60L 1/003 to auxiliary motors, e.g. for pumps, compressors
• CPC Class Codes: B60L 1/06 using only one supply
• CPC Class Codes: B60L 15/2045 for optimising the use of energy
• CPC Class Codes: B60L 2210/10 DC to DC converters
• CPC Class Codes: B60L 2210/30 AC to DC converters
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2240/34 Cabin temperature
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2240/545 Temperature
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 2240/80 Time limits
• CPC Class Codes: B60L 2260/44 by parameter estimation
• CPC Class Codes: B60L 2260/46 by self learning
• CPC Class Codes: B60L 2270/12 of exhaust
• CPC Class Codes: B60L 3/0069 relating to the isolation, e.g. ground fault or leak current
• CPC Class Codes: B60L 3/12 Recording operating variables ; Monitoring of operating variables
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/66 Arrangements of batteries
• CPC Class Codes: B60L 53/14 : Conductive energy transfer
• CPC Class Codes: B60L 58/12 : responding to state of charge [SoC]
• CPC Class Codes: B60L 58/16 : responding to battery ageing, e.g. to the number of charging cycles or the state of health [SoH]
• CPC Class Codes: B60L 58/20 : having different nominal voltages
• CPC Class Codes: B60L 58/22 : Balancing the charge of battery modules
• CPC Class Codes: B60L 7/14 : for vehicles propelled by ac motors
• CPC Class Codes: B60L 7/26 : Controlling the braking effect
• CPC Class Codes: B60W 10/26 : for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 2510/248 : Age of storage means
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y02T 90/12 : Electric charging stations
• CPC Class Codes: Y02T 90/14 : Plug-in electric vehicles
• CPC Class Codes: Y10S 903/907 : Electricity storage, e.g. battery, capacitor

Abstract

Hybrid-electric and pure electric vehicles include a traction battery. During vehicle operation, impedance parameters of the traction battery may be estimated. To ensure accurate estimation results, certain persistent excitation criteria may be met. These conditions may not always be met, in which case active excitation of the traction battery power demand may be initiated. The invocation of active battery excitation may be based on a variability of estimates of a battery parameter and an age of a most recent estimate of the battery parameter. As the variability of the parameter estimates increases, the time between active battery excitation requests may decrease.

Claims

1. A powertrain control system for a vehicle comprising:

at least one controller programmed to, in response to a variability of estimates of a battery parameter and an age of a most recent estimate of the battery parameter exceeding associated thresholds, excite a battery to cause an amplitude, corresponding to at least one frequency associated with battery power demand within a predetermined frequency range, to exceed a predetermined magnitude when all amplitudes corresponding to frequencies within the predetermined frequency range are less than the predetermined magnitude.

2. The powertrain control system of claim 1 wherein the at least one controller is further programmed to excite the battery further in response to a time elapsed since an immediately previous excitation exceeding a threshold that decreases as the variability increases.

3. The powertrain control system of claim 1 wherein the at least one controller is further programmed to excite the battery further based on an age of the battery.

4. The powertrain control system of claim 3 wherein the at least one controller is further programmed to excite the battery further in response to a time elapsed since an immediately previous excitation exceeding a threshold that increases as the age of the battery increases.

5. The powertrain control system of claim 1 wherein the variability is based on a standard deviation of previously learned estimates of the battery parameter.

6. The powertrain control system of claim 1 wherein the at least one controller is further programmed to estimate the battery parameter when the amplitude exceeds the predetermined magnitude.

7. The powertrain control system of claim 1 wherein the at least one controller is further programmed to estimate the battery parameter at a plurality of state of charge and temperature values.

8. A method of controlling a vehicle comprising:

exciting a traction battery to cause an amplitude corresponding to at least one frequency associated with battery power demand within a predefined frequency range to exceed a predetermined magnitude in response to a variability of estimates of a battery parameter and an age of a most recent estimate of the battery parameter exceeding associated thresholds;

and operating an engine and an electric machine to offset changes in battery power demand.

9. The method of claim 8 wherein a time between excitations decreases as the variability increases.

10. The method of claim 8 wherein exciting the traction battery is further based on an age of the traction battery.

11. The method of claim 10 wherein a time between the excitations increases as the age of the traction battery increases.

12. The method of claim 8 wherein the variability is based on a standard deviation of a plurality of previously learned estimates of the battery parameter.

13. The method of claim 12 further comprising estimating the battery parameter when the amplitude exceeds the predetermined magnitude, and operating the traction battery according to the estimate of the battery parameter.

14. A vehicle comprising:

a traction battery; and

at least one controller programmed to, in response to a variability of estimates of a battery parameter and an age of a most recent estimate of the battery parameter exceeding associated thresholds, excite the traction battery to cause, for at least one frequency associated with battery power demand within a predefined frequency range, a corresponding amplitude to exceed a predetermined magnitude.

15. The vehicle of claim 14 wherein the at least one controller is further programmed to excite the traction battery further in response to a time elapsed since an immediately previous excitation exceeding a threshold that decreases as the variability increases.

16. The vehicle of claim 14 wherein the at least one controller is further programmed to excite the traction battery based on an age of the traction battery.

17. The vehicle of claim 14 wherein the at least one controller is further programmed to excite the traction battery further in response to a time elapsed since an immediately previous excitation exceeding a threshold that increases as the age of the traction battery increases.

18. The vehicle of claim 14 wherein the at least one controller is further programmed to estimate the battery parameter when the corresponding amplitude exceeds the predetermined magnitude.

19. The vehicle of claim 14 wherein the predetermined frequency range and the predetermined magnitude are defined by traction battery impedance parameters.

20. The vehicle of claim 14 further comprising an engine, an electric machine, an electrical load and a wheel brake wherein the at least one controller is further programmed to operate one or more of the engine, the electric machine, the electrical load and the wheel brake to cause a change in battery power demand to excite the traction battery and offset changes in wheel power caused by the change in battery power demand such that acceleration of the vehicle is not affected by the change in battery power demand.