Variable carrier switching frequency control of variable voltage converter

• US 10,239,407 B2
• Filed: 01/25/2016
• Issued: 03/26/2019
• Est. Priority Date: 01/25/2016
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Yu, Lan, Degner, Michael W.
• Primary Examiner(s): Donovan, Lincoln
• Assistant Examiner(s): Almo, Khareem E
• Application Number:
  US15/005,671
• Publication Number:
  US 20170210233A1
• Time in Patent Office: 1,156 Days
• Field of Search: None
• CPC Class Codes: B60L 15/007 Physical arrangements or structures of drive train converters specially adapted for the propulsion motors of electric vehicles
• CPC Class Codes: B60L 2210/10 DC to DC converters
• CPC Class Codes: B60L 2240/527 Voltage
• CPC Class Codes: B60L 2240/529 Current
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 2270/142 acoustic
• CPC Class Codes: B60L 50/15 with additional electric power supply with capacitors charged by engine-driven generators B60L50/40; with batteries charged by engine-driven generators B60L50/61
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/51 characterised by AC-motors
• CPC Class Codes: B60L 53/14 Conductive energy transfer
• CPC Class Codes: H02M 3/155 using semiconductor devices only
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles

Abstract

A controller is configured to select a rate of change direction of an output voltage of a variable voltage converter (VVC) based on a direction of current flow associated with a capacitor of the VVC, and to adjust a magnitude of the rate of change direction based on directions of current flow associated with the capacitor and an electric machine coupled to the VVC.

Claims

1. An electric vehicle power conversion system comprising:

a variable voltage converter, including a capacitor, configured to generate an output voltage for a load; and

a controller configured to select a rate of change direction for the output voltage based on a current flow direction of the capacitor, and to adjust a magnitude of the rate of change direction based on the current flow direction and a load current flow direction.

2. The system of claim 1, wherein the rate of change direction is positive in response to the current flow direction being into the capacitor.

3. The system of claim 2, wherein adjusting the magnitude includes decreasing the magnitude in response to the current flow direction and load current flow direction being same.

4. The system of claim 2, wherein adjusting the magnitude includes increasing the magnitude in response to the current flow direction and load current flow direction being opposite.

5. The system of claim 1, wherein the rate of change direction is negative in response to the current flow direction being from the capacitor.

6. The system of claim 5, wherein adjusting the magnitude includes decreasing the magnitude in response to the current flow direction and load current direction being same.

7. The system of claim 5, wherein adjusting the magnitude includes decreasing the magnitude in response to the current flow direction and load current direction being opposite.

8. A vehicle comprising:

an electric machine;

a variable voltage converter, including a capacitor, configured to produce a voltage for the electric machine; and

a controller configured to select a positive rate of change direction for the voltage in response to a current flow direction being into the capacitor, and to decrease a magnitude of the rate of change direction in response to the current flow direction and an electric machine current flow direction being same.

9. The vehicle of claim 8, wherein the controller is further configured to select a negative rate of change direction for the voltage in response to the current flow direction being from the capacitor.

10. The vehicle of claim 8, wherein the controller is further configured to increase the magnitude in response to the current flow direction and electric machine current flow direction being opposite.

11. The vehicle of claim 8, wherein the controller is further configured to decrease the magnitude using a filter or voltage schedule look-up table.

12. A controller-implemented method for operating an electric powertrain DC-DC converter coupled with an electric machine comprising:

selecting a rate of change direction of an output voltage of the converter based on a current flow direction of a capacitor of the converter; and

adjusting a magnitude of the rate of change direction based on the current flow direction of the capacitor and a current flow direction of the electric machine.

13. The method of claim 12, wherein the rate of change direction is positive in response to the current flow direction being into the capacitor.

14. The method of claim 12, wherein the rate of change direction is negative in response to the current flow direction being from the capacitor.

15. The method of claim 12, wherein the adjusting includes increasing the magnitude in response to the current flow directions being opposite.

16. The method of claim 12, wherein the adjusting includes decreasing the magnitude in response to the current flow directions being same.

17. The method of claim 12, wherein the adjusting is further based on a magnitude of current flow to the capacitor and a magnitude of current flow to the electric machine.