Active battery parameter identification using conditional extended kalman filter

• US 9,718,455 B2
• Filed: 02/20/2014
• Issued: 08/01/2017
• 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
• Primary Examiner(s): PAIGE, TYLER D
• Application Number:
  US14/184,742
• Publication Number:
  US 20150232083A1
• Time in Patent Office: 1,258 Days
• Field of Search: 701 22, 320132, 702 63
• 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 method of controlling a vehicle comprising:

operating an engine and an electric machine to cause, during vehicle motion having a period of battery power demand in which frequency component amplitudes of battery power demand falling within a predetermined frequency range are 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 vehicle acceleration.

2. The method of claim 1 further comprising operating an electrical load configured to consume power to cause at least one of the frequency component amplitudes to exceed the predetermined magnitude to excite the traction battery for estimating parameters without affecting vehicle acceleration.

3. The method of claim 1 further comprising distributing power for satisfying wheel power demand and causing the at least one frequency component amplitudes to exceed the predetermined magnitude between the engine and the electric machine, and operating the engine and electric machine based on the distribution of power.

4. The method of claim 3 further comprising operating at least one wheel brake to reduce wheel power when the electric machine and the engine are operated at a power level that exceeds the wheel power demand.

5. A vehicle comprising:

a traction battery; and

a controller programmed to estimate N parameters of the traction battery, and during vehicle motion having a period of battery power demand in which frequency component amplitudes of battery power demand falling within a predetermined frequency range are below a predetermined magnitude, cause more than N/2 frequency component amplitudes to exceed the predetermined magnitude to excite the traction battery without affecting vehicle acceleration.

6. The vehicle of claim 5 further comprising an electric machine, and wherein the 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.

7. The vehicle of claim 6 further comprising an engine, and wherein the controller is further programmed to control the engine without affecting an amount of power output to satisfy wheel power demand.

8. The vehicle of claim 6 further comprising at least one wheel brake, and wherein the controller is further programmed to control the at least one wheel brake to offset changes in the power output of the electric machine.

9. The vehicle of claim 5 further comprising an electrical load, and wherein the 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.

10. The vehicle of claim 5 wherein the predetermined frequency range and the predetermined magnitude are defined by traction battery impedance parameters.

11. The vehicle of claim 5 wherein the 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.

12. The vehicle of claim 5 wherein the 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.