Method and apparatus for average current control

• US 8,324,869 B2
• Filed: 08/20/2010
• Issued: 12/04/2012
• Est. Priority Date: 08/20/2010
• Status: Active Grant

• Current Assignee: Hamilton Sundstrand Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Hamilton Sundstrand Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Nguyen, Vietson M., Swenson, Josh C., Vedula, Sastry V.
• Primary Examiner(s): Tso, Edward
• Application Number:
  US12/859,928
• Publication Number:
  US 20120043944A1
• Time in Patent Office: 837 Days
• Field of Search: 320/107, 320/128, 320/140, 320/163, 320/166, 323/284, 323/285, 323/271
• US Class Current: 320/166
• CPC Class Codes: H02J 7/34 Parallel operation in networks using both storage and other dc sources, e.g. providing buffering H02J7/14 takes precedence
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators

Abstract

A method and apparatus for controlling a converter circuit within the electrical accumulator unit based on a comparison between an actual average converter current and a desired average converter current.

Claims

1. A method for controlling a power converter comprising the steps of:

determining an operating mode using a controller;

controlling a power converter by performing the steps of;

determining a desired average current based at least partially on said operating mode using the controller;

determining an actual average current over a time period equal to one switching cycle of the power converter;

comparing said desired average current flow with said actual average current; and

outputting a control signal capable of adjusting a current based at least partially on said comparison.

2. The method of claim 1, wherein said step of determining an operating mode further comprises selecting an operating mode from a list comprising a boost mode, a stand-by mode, or a buck mode.

3. The method of claim 2, wherein said step of determining an actual average current comprises integrating a measured inductor current over a time period equal to one switching cycle of the power converter, and dividing the integrated inductor current by a value equal to a number of seconds in said time period, thereby determining an average current when said operating mode is a boost mode.

4. The method of claim 3, wherein the measured inductor current is an inductor filter current.

5. The method of claim 3, wherein said step of determining an actual average current further comprises the steps of detecting a falling edge of a control signal and resetting an integration value to a starting value when said falling edge is detected and said operating mode is a boost mode.

6. The method of claim 2, wherein said step of determining an actual average current further comprises the steps of integrating a measured transistor current over a time period equal to one switching cycle of the power converter and dividing the integrated transistor current by a value equal to a number of seconds in said time period, thereby determining an average current when said operating mode is a buck mode.

7. The method of claim 6, wherein said measured transistor current is a buck switch transistor current.

8. The method of claim 6, wherein said step of determining an actual average current when said operating mode is a buck mode further comprises the steps of:

detecting a rising edge of a control signal;

starting an integrator in response to said rising edge;

detecting a falling edge of a control signal;

stopping an integrator in response to said falling edge;

integrating a measured current over a time period starting at said rising edge and ending at said falling edge;

dividing said integrated measured current by a number of seconds in said time period, thereby determining an average converter current.

9. The method of claim 8, further comprising the steps of resetting an integrator to an original value when a falling edge is detected.

10. The method of claim 2, wherein said steps of determining a desired average current using the controller, determining an actual average current over a time period equal to one switching cycle of the power converter, comparing said desired average current with said actual average current, and outputting a control signal capable of adjusting a current based at least partially on said comparison are suspended while said operating mode is a stand-by mode.

11. The method of claim 1, wherein said step of determining a desired average current comprises the steps of:

receiving a desired average current value at a summer from a controller;

receiving a stabilizing signal at said summer from the controller;

summing said desired average current value and said stabilizing signal using said summer; and

outputting a stabilized desired average current value from said summer.

12. The method of claim 11, wherein said stabilizing signal comprises a down ramp signal.

13. An electrical accumulator unit comprising:

a power filter having electrical connections for connecting to a power bus;

a power converter connected to said filter;

a power storage component connected to said power converter; and

a controller capable of controlling said power filter, said power converter, and said power storage component based on a desired average current and an actual average current.

14. The electrical accumulator unit of claim 13, wherein said controller comprises a buck mode control loop circuit and a boost mode control loop circuit controllably connected to at least one of said power converter, said power filter, and said power storage component, each of said control loop circuits having inputs for receiving a desired average current value from a controller.

15. The electrical accumulator unit of claim 13, wherein said power converter further comprises a filter inductor, a boost switch, and a buck switch.

16. The electrical accumulator unit of claim 15, wherein said power converter further comprises a sensor capable of detecting a current passing through said filter inductor.

17. The electrical accumulator unit of claim 15, wherein said power converter further comprises a sensor capable of detecting a current passing through said buck switch.

18. A method for controlling an electrical accumulator unit current comprising the steps of:

determining an operating mode using a controller;

controlling an electrical accumulator unit power converter, and thereby controlling said electrical accumulator unit power accumulation functions by performing the steps of;

determining a desired average converter current based at least partially on said operating mode using the controller;

determining an actual average converter current over a time period equal to one iteration of the method;

comparing said desired average converter current with said actual average converter current; and

outputting a control signal capable of adjusting a converter current based at least partially on said comparison.