Fast Transient Step Load Response in a Power Converter

• US 20090085546A1
• Filed: 09/24/2008
• Published: 04/02/2009
• Est. Priority Date: 09/28/2007
• Status: Active Grant

• Current Assignee: Astec International Limited (Emerson Electric Company)
• Original Assignee: Astec International Limited (Emerson Electric Company)
• Inventors: Boncato, Yancy F., Asuncion, Arlaindo V., Phadke, Vijay G., Espina, Evan M.
• Granted Patent: US 8,232,786 B2
• Time in Patent Office: Days
• US Class Current: 323/284
• CPC Class Codes: H02M 1/4225 using a non-isolated boost converter
• CPC Class Codes: H02M 3/157 with digital control
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A method of controlling a power converter having at least one switching device for supplying an output voltage and a load current to a load is disclosed. The method includes sensing the output voltage and sensing the load current. The method further includes controlling a duty cycle of the switching device according to the sensed output voltage and a voltage control loop when a rate of change of the load current does not exceed a threshold level. The method also includes adjusting the duty cycle of the switching device set by the voltage control loop when the rate of change of the load current exceeds the threshold level.

Claims

1. A method of controlling a power converter having at least one switching device for supplying an output voltage and a load current to a load, the method comprising:

sensing the output voltage;

sensing the load current;

controlling a duty cycle of the switching device according to the sensed output voltage and a voltage control loop when a rate of change of the load current does not exceed a threshold level; and

adjusting the duty cycle of the switching device set by the voltage control loop when the rate of change of the load current exceeds the threshold level.

2. The method of claim 1 wherein adjusting includes adjusting the duty cycle of the switching device before sensing a change in the output voltage due to the rate of change of the load current.

3. The method of claim 2 wherein adjusting includes increasing the duty cycle of the switching device when the load current is increasing, and decreasing the duty cycle of the switching device when the load current is decreasing.

4. The method of claim 2 wherein sensing the output voltage includes sampling the output voltage at a first frequency, and wherein sensing the load current includes sampling the load current at a second frequency that is greater than the first frequency.

5. The method of claim 1 wherein adjusting includes adjusting the duty cycle of the switching device according to the sensed load current.

6. The method of claim 1 wherein the power converter is a DC-DC converter.

7. The method of claim 1 wherein the power converter is a PFC boost converter.

8. The method of claim 1 wherein the power converter is a voltage regulation module (VRM).

9. The method of claim 1 wherein the power converter includes a digital controller for controlling and adjusting the duty cycle of the switching device.

10. The method of claim 9 wherein the digital controller is configured to sense the output voltage by sampling the output voltage and sense the load current by sampling the load current.

11. A power converter comprising a controller and at least one switching device, the controller configured to control a duty cycle of the switching device according to a sensed output voltage and a voltage control loop when a rate of change of a load current does not exceed a threshold level, and to adjust the duty cycle of the switching device set by the voltage control loop when the rate of change of the load current exceeds the threshold level.

12. The power converter of claim 11 wherein the power converter is configured to sample the output voltage at a first frequency and sample the load current at a second frequency that is greater than the first frequency.

13. The power converter of claim 11 wherein the controller is configured to sample the output voltage.

14. The power converter of claim 13 wherein the controller includes a sampling circuit for sampling the load current.

15. The power converter of claim 14 wherein the controller is a digital controller.

16. The power converter of claim 11 further comprising a sampling circuit for sampling the load current.

17. The power converter of claim 11 wherein the power converter is a DC-DC converter.

18. The power converter of claim 11 wherein the power converter is a PFC boost converter.

19. The power converter of claim 11 wherein the power converter is a voltage regulation module (VRM).