Transformer coupled current capping power supply topology

• US 9,450,452 B2
• Filed: 04/03/2012
• Issued: 09/20/2016
• Est. Priority Date: 04/03/2012
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Inventors: Harris, Shaun L., Peterson, Eric C.
• Primary Examiner(s): Fureman, Jared
• Assistant Examiner(s): Barnett, Joel
• Application Number:
  US13/438,540
• Publication Number:
  US 20130257160A1
• Time in Patent Office: 1,631 Days
• Field of Search: 307 64- 66, 307 44- 46
• US Class Current: 1/1
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 9/06 with automatic change-over , e.g. UPS systems
• CPC Class Codes: H02J 9/061 for DC powered loads
• CPC Class Codes: H02M 1/0009 Devices or circuits for detecting current in a converter
• CPC Class Codes: H02M 1/08 Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
• CPC Class Codes: H02M 1/4208 Arrangements for improving power factor of AC input
• CPC Class Codes: H02M 3/33515 with digital control
• CPC Class Codes: Y02B 70/30 Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
• CPC Class Codes: Y04S 20/20 End-user application control systems

Abstract

Described is a technology by which magnetic flux is used to provide backup power. A transformer has a line power source controllably coupled to a first input winding, and secondary power source controllably coupled to a second input winding. A controller monitors the line power and switches to the secondary power source if the line power voltage drops too low, or uses the secondary power source to augment the line power source if the line power current gets too high. Also described is incrementally transitioning from the secondary power source back to the line power source.

Claims

1. A load transfer mechanism for a power supply, the load transfer mechanism comprising:

a transformer having a first input winding, a second input winding, and an output winding, the first input winding corresponding to a primary side isolated from a secondary side corresponding to the output winding, the output winding corresponding to a rectifier configured to convert alternating current to direct current;

a controller configured to switch load associated with the output winding between at least one of a first source of power associated with the first input winding or a second source of power associated with the second input winding to achieve a desired output voltage corresponding to the output winding; and

a first coupling mechanism configured to provide selective coupling and decoupling of a charging circuitry to the second source of power,

wherein the controller is configured for;

monitoring a power supply state associated with the first input winding, a first duty cycle associated with charging the second source of power, and a second duty cycle associated with the rectifier to determine switching of the load,

selectively coupling the first source of power to the first input winding, and

selectively controlling the first coupling mechanism to selectively recharge the second source of power based upon the first duty cycle associated with charging the second source of power.

2. The load transfer mechanism of claim 1 wherein the controller is further configured to detect an under voltage protection state corresponding to the first source of power, and in response, to switch the load to the second source of power.

3. The load transfer of claim 2 wherein the controller no longer detects the under voltage protection state corresponding to the first source of power, and wherein in response, the controller incrementally transitions at least some of the load from the second source of power to the first source of power.

4. The load transfer mechanism of claim 3 wherein the controller is configured to incrementally transition the at least some of the load by increasing a third duty cycle associated with the first source of power and by decreasing a fourth duty cycle corresponding with the second source of power.

5. The load transfer mechanism of claim 1 wherein the controller is further configured to detect an over current state corresponding to the first source of power, and in response, to switch at least part of the load to the second source of power.

6. The load transfer mechanism of claim 5 wherein the controller no longer detects the over current state corresponding to the first source of power, and wherein in response, the controller incrementally transitions at least some of the load from the second source of power to the first source of power.

7. The load transfer mechanism of claim 6 wherein the controller incrementally transitions the at least some of the load by increasing a third duty cycle associated with the first source of power and by decreasing a fourth duty cycle associated with the second source of power.

8. The load transfer mechanism of claim 1 wherein the load transfer mechanism is coupled to a computer system.

9. The load transfer mechanism of claim 1 further comprising a coupling mechanism configured to provide selective coupling and decoupling of the second source of power to the load transfer mechanism, wherein the controller is configured to monitor the first duty cycle associated with the second source of power to determine switching of the load and, based at least in part on the first duty cycle associated with the second source of power, control the second coupling mechanism.

10. The load transfer mechanism of claim 1 wherein the controller runs on the primary side with respect to voltage and ground, and wherein the second input winding corresponds to the secondary side.

11. The load transfer mechanism of claim 1 wherein the controller runs on the secondary side with respect to voltage and ground, and wherein the second input winding corresponds to the secondary side.

12. The load transfer mechanism of claim 1 wherein the controller is coupled to a backup power source to allow the controller to operate when no power is available from the first or second source of power.

13. One or more computer memory apparatus having computer-executable instructions, which, upon execution, perform operations comprising:

monitoring, at one or more sensor interfaces, a power supply state associated with a first input winding, a duty cycle associated with charging a local energy storage that is associated with a second input winding, and a duty cycle associated with a rectifier, the first input winding corresponding to a primary side of a transformer isolated from a secondary side of the transformer corresponding to an output winding corresponding to the rectifier, and

switching load associated with the output winding between a first source of power associated with the first input winding and the local energy storage associated with the second input winding to achieve a desired output voltage corresponding to the output winding through selectively controlling a coupling mechanism to selectively recharge the local energy storage, based upon at least the duty cycle associated with charging the local energy, storage.

14. The one or more computer-readable media of claim 13 having further computer-executable instructions, which, upon execution, perform operations comprising detecting that an input voltage is below an under voltage protection threshold and, in response, switching power from the local energy storage to the second input winding of the transformer, and detecting that the input voltage is no longer below the under voltage protection threshold, and in response, switching to couple power from the first source of power to the first input winding of the transformer.

15. The one or more computer memory apparatus of claim 13 having further computer-executable instructions, which, upon execution, perform operations comprising monitoring current corresponding to power from the first source of power, and if the current exceeds an over current state, switching to couple at least some power from the local energy storage to the second input winding of the transformer.

16. The one or more computer memory apparatus of claim 15 having further computer-executable instructions, which, upon execution, perform operations comprising detecting that an input current no longer exceeds the over current state, and in response, switching to decouple at least some of the power from the local energy storage to the second input winding of the transformer.

17. A method comprising:

monitoring a power supply state associated with a first transformer winding, a first duty cycle associated with charging a local energy storage that is associated with a second transformer winding, and a second duty cycle associated with a rectifier, the first transformer winding corresponding to a primary side of a transformer isolated from a secondary side of the transformer corresponding to an output winding corresponding to the rectifier configured to convert alternating current to direct current; and

switching load associated with the output winding between a first power source associated with the first transformer winding and the local energy storage associated with the second transformer winding to achieve a desired output voltage corresponding to the output winding by controllably coupling the first power source and the local energy storage through magnetic flux to provide a power supply, including automatically controlling switching mechanisms to input power from the local energy storage to the second transformer winding based upon the first duty cycle associated with charging the local energy storage.

18. The method of claim 17 further comprising, monitoring a voltage level corresponding to the first power source, and controllably coupling the local energy storage to the second transformer winding when the voltage level is below a threshold.

19. The method of claim 17 further comprising, monitoring a current level corresponding to the first power source, and controllably coupling the local energy storage to the second transformer winding when the current level is above a threshold.

20. The method of claim 17 further comprising monitoring a first duty cycle associated with the local energy storage, and controllably coupling the local energy storage to the transformer based at least in part on the second duty cycle associated with the local energy source.