Active Battery Parameter Identification Using Conditional Extended Kalman Filter

• US 20150232083A1
• Filed: 02/20/2014
• Published: 08/20/2015
• 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: Yu, Hai, Li, Yonghua
• Granted Patent: US 9,718,455 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 20/15 Control strategies specially adapted for achieving a particular effect
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

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. During periods of generally constant battery power demand in which a predetermined range of frequency component amplitudes of battery power demand is less than a predetermined magnitude, active excitation may be desired. A controller may cause at least one of the frequency component amplitudes to exceed the predetermined magnitude without affecting acceleration of the vehicle. Battery power demand may be affected by operation of an electric machine and an electrical load. An engine and a wheel brake may be operated to offset changes in battery power demand such that driver wheel output power is not affected.

Claims

1. A powertrain control system for a vehicle comprising:

at least one controller programmed to, during a period of generally constant battery power demand in which a predetermined range of frequency component amplitudes of battery power demand is less than a predetermined magnitude, cause at least one of the frequency component amplitudes to exceed the predetermined magnitude without affecting acceleration of the vehicle.

2. The powertrain control system of claim 1 wherein a number of the at least one frequency component amplitudes is greater than half of a number of battery parameters to be estimated.

3. The powertrain control system of claim 1 wherein the at least one controller is further programmed to cause the at least one of the frequency component amplitudes to exceed the predetermined magnitude for a predetermined period of time.

4. The powertrain control system of claim 1 wherein the predetermined range and the predetermined magnitude are defined by battery impedance parameters.

5. The powertrain control system of claim 1 wherein the at least one controller is further programmed to cause the at least one of the frequency component amplitudes to exceed the predetermined magnitude by controlling a power distribution between an engine power output and an electric machine power output.

6. The powertrain control system of claim 1 wherein the at least one controller is further programmed to cause the at least one of the frequency component amplitudes to exceed the predetermined magnitude by controlling power consumed by an electrical load.

7. The powertrain control system of claim 1 wherein the at least one controller is further programmed to cause the at least one of the frequency component amplitudes to exceed the predetermined magnitude by controlling an electric machine power output and operating a wheel brake to offset changes in the electric machine power output.

8. A method of controlling a vehicle comprising:

operating at least one electrical component to cause, during a period of generally constant battery power demand in which a predetermined range of frequency component amplitudes of battery power demand is less than a predetermined magnitude, at least one of the frequency component amplitudes to exceed the predetermined magnitude to excite a traction battery for estimating parameters without affecting acceleration of the vehicle.

9. The method of claim 8 wherein the at least one electrical component is an electrical load configured to consume power.

10. The method of claim 8 wherein the at least one electrical component is an electric machine, further comprising distributing power for satisfying wheel power demand between an engine and the electric machine, and operating the engine and electric machine based on the distribution of power.

11. The method of claim 8 wherein the at least one electrical component is an electric machine, and further comprising operating at least one wheel brake to reduce wheel power when the electric machine is operated at a power level at which wheel power demand is exceeded.

12. A vehicle comprising:

a traction battery; and

at least one controller programmed to estimate N parameters of the traction battery, and during a period in which a predetermined range of frequency component amplitudes of battery power demand is below a predetermined magnitude, cause more than N/2 frequency component amplitudes to exceed the predetermined magnitude to excite the traction battery for parameter estimation without affecting acceleration of the vehicle.

13. The vehicle of claim 12 further comprising an electric machine, and wherein the at least one controller is further programmed to cause the more than N/2 frequency components to exceed the predetermined magnitude by controlling a power output of the electric machine.

14. The vehicle of claim 13 further comprising an engine, and wherein the at least one controller is further programmed to control the engine without affecting an amount of power output to satisfy wheel power demand.

15. The vehicle of claim 13 further comprising at least one wheel brake, and wherein the at least one controller is further programmed to control the at least one wheel brake to offset changes in the power output of the electric machine.

16. The vehicle of claim 12 further comprising an electrical load, and wherein the at least one controller is further programmed to control power consumed by the electrical load to cause the more than N/2 frequency component amplitudes to exceed the predetermined magnitude.

17. The vehicle of claim 12 wherein the predetermined range and the predetermined magnitude are defined by traction battery impedance parameters.

18. The vehicle of claim 12 wherein the at least one controller is further programmed to cause the more than N/2 frequency component amplitudes to exceed the predetermined magnitude in response to a temperature associated with the traction battery being less than a predetermined temperature.

19. The vehicle of claim 12 wherein the at least one controller is further programmed to cause the more than N/2 frequency component amplitudes to exceed the predetermined magnitude in response to a state of charge of the traction battery being within a predetermined range.

20. The vehicle of claim 12 wherein the at least one controller is further programmed to cause the more than N/2 frequency component amplitudes to exceed the predetermined magnitude in response to detection of a period of generally constant battery power demand.