Optimizing system performance using state of health information

• US 8,612,079 B2
• Filed: 12/14/2011
• Issued: 12/17/2013
• Est. Priority Date: 12/14/2011
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Tang, Xidong, Salman, Mutasim A., Zhang, Yilu
• Primary Examiner(s): To, Tuan C.
• Assistant Examiner(s): SMITH, JELANI A
• Application Number:
  US13/325,132
• Publication Number:
  US 20130158755A1
• Time in Patent Office: 734 Days
• Field of Search: 701/36, 701/22, 701/31.4, 701/32.9, 701/34.4, 701/123, 701/29.1, 701/29.7, 701/29, 701/30.5, 701/30.6, 701/30.7, 701/31.1, 701/32.7, 701/3, 701/32.2, 701/63, 701/1, 702/63, 703/13, 705/305, 714/1, 320/134, 320/149, 320/132
• US Class Current: 701/22
• CPC Class Codes: B60W 20/50 Control strategies for responding to system failures, e.g. for fault diagnosis, failsafe operation or limp mode
• CPC Class Codes: G05B 23/0294 Optimizing process, e.g. process efficiency, product quality
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

A method for optimizing performance of a system includes determining, via a controller, a state of health (SOH) for each of a plurality of components of the system, and determining a state of function (SOF) of the system using the SOH of each component. The method includes estimating the remaining useful life (RUL) of the system using the system SOF, selecting a cost-optimal control strategy for the system using a costing model, and dynamically, i.e., in real time, executing the selected strategy to extend the estimated RUL. The method may include comparing the selected cost-optimal strategy to a calibrated performance threshold, and executing the selected strategy only when the selected strategy exceeds the threshold. A system includes first and second components and a controller. The controller dynamically executes the above method with respect to the components, which may be a traction motor and battery in one possible embodiment.

Claims

1. A method for controlling a system having a plurality of components, the method comprising:

determining, via a controller, a normalized state of health (SOH) value for each of the components, wherein a normalized SOH value of 1 corresponds to a calibrated or new component and a normalized SOH value of 0 corresponds to a non-functioning component;

determining a state of function (SOF) value of the system as a function of the SOH value of each of the components;

estimating a remaining useful life of the system using the SOF value of the system;

estimating a plurality of different component-level costs via a component-level costing model, wherein each component-level cost is an estimated cost of extending the life of a respective one of the components;

determining, via a system-level costing model, a cost of each of a plurality of different control strategies as a function of the estimated component-level costs;

selecting a control strategy from the plurality of different control strategies which minimizes operating costs while producing a threshold SOF value and a threshold remaining useful life of the components; and

dynamically executing the selected control strategy via the controller.

2. The method of claim 1, wherein estimating the remaining useful life of the system includes using an aging model.

3. The method of claim 2, wherein determining the SOF of the system includes processing the SOH value of each of the components and an output of the aging model through a system function model.

4. The method of claim 1, wherein determining the SOH value includes measuring and recording a set of current performance values for each of the components, and then processing the recorded performance values through an SOH model.

5. The method of claim 1, further comprising:

modifying a set of system constraints via the controller when the estimated remaining useful life is less than a calibrated life threshold.

6. The method of claim 1, wherein the system is an electrical propulsion system for a vehicle, and wherein the plurality of components includes an electric traction motor and a battery pack that is electrically connected to the traction motor.

7. A method for controlling a system having a plurality of components, the method comprising:

using a sensor array to measure and record a set of current performance values for each of the components;

calculating, via a controller, a normalized state of health (SOH) value for each of the components by processing the recorded current performance values through an SOH model, wherein a normalized SOH value of 1 corresponds to a calibrated or new component and a normalized SOH value of 0 corresponds to a non-functioning component;

determining a state of function (SOF) value of the system using an SOF model that models an SOF value of the system as a function of the corresponding SOH value of each of the components;

estimating the remaining useful life of the system using the SOF value of the system using an aging model;

processing a set of possible system control strategies through a component-level costing model to thereby estimate the cost of extending the life of a respective one of the components via each of the set of possible system control strategies;

determining, via a system-level costing model, a cost of each of a plurality of different control strategies as a function of the estimated component-level costs;

selecting a system control strategy from the set of possible system control strategies which minimizes operating costs of the system while producing a threshold SOF value and a threshold remaining useful life of the components; and

dynamically executing the selected control strategy via the controller.

8. The method of claim 7, further comprising modifying a set of system constraints when the remaining useful life is less than a calibrated threshold.

9. The method of claim 7, wherein the system is used in a vehicle, and wherein dynamically executing the selected control strategy includes modifying a powertrain control strategy of the vehicle in real time.

10. The method of claim 7, wherein the system is an electrical propulsion system for a vehicle, and wherein the plurality of components includes an electric traction motor and a battery pack that is electrically connected to the traction motor.

11. The method of claim 10, wherein executing the selected system control strategy includes one of:

changing a speed of the traction motor and changing a charging or discharging rate of the battery pack.

12. A system comprising:

a first component;

a second component;

a controller in communication with each of the first and second components, wherein the controller is configured to;

determine a normalized state of health (SOH) value for each of the first and second components, wherein a normalized SOH value of 1 corresponds to a calibrated or new component and a normalized SOH value of 0 corresponds to a non-functioning component;

determine a state of function (SOF) value of the system as a function of the SOH value of each of the components;

estimate the remaining useful life of the system using the SOF value of the system;

estimate a plurality of different component-level costs via a component-level costing model, wherein each component-level cost is an estimated cost of extending the life of a respective one of the components;

process a set of control strategies through a component-level costing model to thereby estimate the cost of extending the life of a respective one of the components via-each of the set of possible system control strategies;

determining, via a system-level costing model, a cost of each of a plurality of different control strategies as a function of the estimated component-level costs;

select a system control strategy from the set of possible system control strategies which minimizes operating costs of the system while producing a threshold SOF value and a threshold remaining useful life of the components; and

dynamically execute the selected control strategy.

13. The vehicle of claim 12, further comprising a sensor array in communication with the controller, wherein the sensor array measures a set of current performance values for each of the first and second components and transmits the measured set of current performance values to the controller, and wherein the controller determines the SOH value for each of the components as a function of the measured set of current performance values.

14. The vehicle of claim 12, wherein the controller estimates the remaining useful life of the system using a component-level aging model, and calculates the SOF value of the system by processing the SOH value of each of the components and an output of the component-level aging model using a system function model.

15. The vehicle of claim 12, wherein the first component is an electric traction motor and the second component is a battery pack that is electrically connected to the traction motor.

16. The vehicle of claim 12, further comprising an internal combustion engine, wherein the controller executes the selected system control strategy in part by controlling an operation of the engine when the estimated remaining useful life of one of the motor and the battery is below a calibrated remaining useful life threshold.