High voltage bus contactor fault detection

• US 10,516,189 B2
• Filed: 11/15/2016
• Issued: 12/24/2019
• Est. Priority Date: 11/15/2016
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Loftus, Michael Edward, Tabatowski-Bush, Benjamin A.
• Primary Examiner(s): Grant, Robert
• Assistant Examiner(s): Trischler, John T
• Application Number:
  US15/352,299
• Publication Number:
  US 20180134169A1
• Time in Patent Office: 1,134 Days
• Field of Search: 320136
• CPC Class Codes: B60L 2240/54 related to batteries
• 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 58/10 for monitoring or controlling batteries
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: H01M 10/425 Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing printed circuits H05K1/00
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• 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: H01M 2010/4271 Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing
• CPC Class Codes: H01M 2220/20 Batteries in motive systems, e.g. vehicle, ship, plane
• CPC Class Codes: H02J 2310/48 for electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: H02J 7/0063 with circuits adapted for supplying loads from the battery
• CPC Class Codes: H02J 7/00712 the cycle being controlled or terminated in response to electric parameters
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A system for a vehicle includes a pair of electrical buses connected to terminals of a traction battery via a shared positive contactor and a pair of negative contactors. The system further includes a controller configured to, responsive to a request to close the contactors and a difference between voltage magnitudes of the buses being greater than a predefined threshold, actively discharge one of the buses to reduce the difference.

Claims

1. A system for a vehicle comprising:

a pair of electrical buses connected to a positive terminal of a traction battery via a shared positive contactor and connected to a negative terminal of the traction battery via a respective one of a pair of negative contactors, such that each bus is connected in parallel with the traction battery and transfers power between the traction battery and a corresponding electrical load when the positive and respective one of the negative contactors are closed; and

a controller configured to, responsive to a request to close the contactors and a difference between voltage magnitudes of the buses being greater than a predefined threshold, actively discharge one of the buses to reduce the difference.

2. The system of claim 1, wherein the controller is further configured to actively discharge the one of the buses such that the voltage magnitudes are within a predefined range of each other.

3. The system of claim 1, wherein the controller is further configured to measure each of the voltage magnitudes via a potential difference between a positive terminal of the shared positive contactor and a respective negative terminal of each of the buses.

4. The system of claim 1, wherein the controller is further configured to initiate pre-charge following the active discharge.

5. The system of claim 1, wherein the controller is further configured to actively discharge one of the buses by selectively applying a resistance across the bus.

6. The system of claim 1, wherein the controller is further configured to measure the difference responsive to confirmation that voltages across the negative contactors are each less than a second predefined threshold following a command resulting from the request to sequentially close the negative contactors.

7. The system of claim 6, wherein the confirmation indicates that each of the voltages has fallen below the second predefined threshold within a predetermined period of time that began with issuance of the command.

8. A method for a vehicle comprising:

responsive to a request to close a pair of contactors and a difference between voltage magnitudes of a pair of electrical buses being greater than a predefined threshold, actively discharging one of the buses until the magnitudes are within a predefined range of each other, wherein the buses are connected to a positive terminal of a traction battery via a shared positive contactor and connected to a negative terminal of the traction battery via a respective one of a pair of negative contactors and each bus is connected in parallel with the traction battery and transfers power from the traction battery to a corresponding electrical load when the positive and respective one of the negative contactors are closed.

9. The method of claim 8 further comprising measuring the voltage magnitudes via a potential difference between a positive terminal of the shared positive contactor and a respective negative terminal of each of the buses.

10. The method of claim 8 further comprising initiating a pre-charge following the active discharge.

11. The method of claim 8, wherein the actively discharging includes selectively applying a resistance across the bus.

12. The method of claim 8 further comprising measuring the difference responsive to a confirmation that voltages across the negative contactors are each less than a second predefined threshold following a command resulting from the request to sequentially close the negative contactors.

13. The method of claim 12, wherein the confirmation indicates that each of the voltages has fallen below the second predefined threshold within a predetermined period of time that began with issuance of the command.

14. A dual-bus arrangement for a vehicle comprising:

a controller configured to, prior to issuing a command to open negative contactors connecting respective negative terminals of a pair of electrical buses to a negative terminal of a traction battery and in response to opening of a shared positive contactor connecting respective positive terminals of the buses to a positive terminal of the traction battery, such that each bus is connected in parallel with the traction battery and transfers power between the traction battery and a corresponding electrical load when the contactors are closed, actively discharge both buses responsive to a voltage magnitude of one of the buses being greater than a predefined threshold.

15. The arrangement of claim 14, wherein the controller is further configured to measure the voltage magnitude via a potential difference between a positive terminal of the positive contactor and a negative terminal of the bus.

16. The arrangement of claim 14, wherein one of the buses defines a main bus configured to transfer energy between the traction battery and a load assisting propulsion of the vehicle.