Control strategy for an electric machine in a vehicle

• US 9,130,487 B2
• Filed: 11/30/2012
• Issued: 09/08/2015
• Est. Priority Date: 08/31/2012
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Isayeva, Rimma, Gabriel, David Crist, Degner, Michael W., Tang, Yuqing, Wu, Hongjie
• Primary Examiner(s): Ro, Bentsu
• Application Number:
  US13/690,540
• Publication Number:
  US 20140062349A1
• Time in Patent Office: 1,012 Days
• Field of Search: 318/139, 318/45, 318/49, 318/66, 318/68, 318/105, 318111-113
• US Class Current: 1/1
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• 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 9/02 electric
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

A hybrid-electric vehicle and method of controlling a hybrid-vehicle is provided. The vehicle includes a traction battery, at least one electric-machine, and a controller. The controller is configured to alter a voltage between the battery and the electric-machine based on a measured voltage of the battery or the high voltage bus. In response to an indication that the measured voltage is faulty during a drive cycle, the controller instead alters the voltage between the battery and the electric machine based on a substituted battery voltage signal such that the electric-machine remains operable for the drive cycle.

Claims

1. A vehicle comprising:

a traction battery;

a high-voltage bus;

an electric machine;

a variable voltage converter electrically coupled between the battery and the bus to convert a traction battery voltage to a high-voltage bus voltage; and

a controller configured to, in response to an indication that a measured voltage signal of the bus is faulty, alter the high-voltage bus voltage based on a substituted battery voltage signal such that the electric machine remains operable for a drive cycle.

2. The vehicle of claim 1 wherein the measured voltage signal is faulty when the measured voltage signal exceeds a threshold range.

3. The vehicle of claim 1 further comprising at least one sensor for providing the measured voltage signal.

4. The vehicle of claim 1 wherein in response to the faulty measured voltage signal, the substituted battery voltage signal is provided by a battery control unit.

5. The vehicle of claim 4 wherein the substituted battery voltage signal is provided from the battery control unit through a vehicle control area network (CAN).

6. A vehicle comprising:

a traction battery;

a high-voltage bus to provide a high-voltage-bus voltage to least one electric machine; and

a controller configured to;

alter the high-voltage-bus voltage between the battery and the electric machine based on a measured voltage signal of the high-voltage bus; and

in response to an indication that the measured voltage signal is faulty, alter the high-voltage-bus voltage between the battery and the electric machine based on a substituted battery voltage signal such that the electric machine remains operable for a drive cycle.

7. The vehicle of claim 6 wherein the controller comprises a variable voltage converter.

8. The vehicle of claim 7 wherein in response to the faulty measured voltage signal of the high-voltage bus, the variable voltage converter is set to a mode that prevents providing a boost voltage to the at least one electric machine.

9. The vehicle of claim 6 wherein the substituted battery voltage signal is equal to a measured battery voltage signal.

10. The vehicle of claim 6 wherein the measured voltage is faulty when the measured voltage exceeds a threshold range.

11. The vehicle of claim 6 further comprising at least one sensor for providing the measured voltage signal of the high-voltage bus.

12. A method of controlling comprising:

varying a voltage between a traction battery and an electric machine based on a measured voltage signal of a high-voltage bus;

in response to an indication that the measured voltage signal is faulty during a drive cycle, substituting an alternate voltage signal; and

varying the voltage between the battery and the electric machine based on the alternate voltage signal such that the electric machine remains operable for the drive cycle.

13. The method of claim 12 wherein if the measured voltage signal is based on a battery voltage, substituting an alternate battery voltage signal provided by a battery control unit.

14. The method of claim 13 wherein the alternate battery voltage signal is provided from the battery control unit through a vehicle control area network (CAN).

15. The method of claim 12, wherein if the measured voltage signal is based on a high voltage bus voltage, substituting an alternate high voltage signal set equal to a battery voltage signal;

and

setting a variable voltage converter to a mode that prevents providing a boost voltage to at least one of the electric machines.