Power supply recovery current history-based limitation

• US 10,199,860 B2
• Filed: 01/28/2017
• Issued: 02/05/2019
• Est. Priority Date: 01/28/2017
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Inventors: Harris, Shaun L., Siegler, John J., Sok, Banha
• Primary Examiner(s): Kaplan, Hal
• Application Number:
  US15/418,688
• Publication Number:
  US 20180219410A1
• Time in Patent Office: 738 Days
• Field of Search: 307 64, 307 66
• CPC Class Codes: H02J 9/00 Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
• CPC Class Codes: H02J 9/04 in which the distribution system is disconnected from the normal source and connected to a standby source
• CPC Class Codes: H02J 9/061 for DC powered loads
• CPC Class Codes: H02J 9/066 characterised by the use of dynamo-electric machines H02J9/08 takes precedence
• CPC Class Codes: H02J 9/08 requiring starting of a prime-mover
• CPC Class Codes: Y02P 80/10 Efficient use of energy, e.g. using compressed air or pressurized fluid as energy carrier

Abstract

A power supply unit (PSU) dynamically limits total recovery current. The PSU includes at least a power input, a power output, a historic maximum power draw memory, an update logic, and a recovery current limiting logic. Some implementations include a latest power measurement register, an hourly max power register, and a rolling max register, and controlling firmware. The update logic monitors a power level. The update logic updates the historic maximum power draw memory to match the monitored level. After a power interruption, the recovery current permitted to flow into the PSU is limited based on the historic usage. The recovery current may be limited in a constant, stepped, or ramped manner. The PSU may also provide power distribution. Multiple PSUs may be treated as a group, allowing an individual PSU to exceed its historic usage while the group'"'"'s recovery currents are limited to the sum of historic usage levels.

Claims

1. A power supply unit (PSU) which dynamically limits total recovery current, comprising:

a power input;

a power output;

a historic maximum power draw memory;

an update logic which in operation monitors an input power level at the PSU power input or an output load at the PSU power output or both to determine a level of power drawn by the PSU from a power infrastructure, and where in operation the update logic updates a value in the historic maximum power draw memory to match the monitored input power level when the monitored input power level exceeds the historic maximum power draw memory value; and

a recovery current limiting logic which in operation after an interruption of power to the PSU permits a recovery current to flow from the power infrastructure through the PSU power output while limiting the recovery current based on the historic maximum power draw memory value.

2. The power supply unit of claim 1, wherein the update logic tracks the input power level at the PSU power input within a given time period thereby determining a present period maximum power draw value, wherein the present period maximum power draw value is less than the historic maximum power draw memory value for a given period, and wherein the update logic lowers the historic maximum power draw memory value to match the present period maximum power draw value.

3. The power supply unit of claim 1, wherein the power supply unit has a rated maximum draw M, and a conversion efficiency E, and wherein the historic maximum power draw memory value is such that the recovery current limiting logic limits the recovery current flowing through the power output to a value that is no greater than 70 percent of M times E.

4. The power supply unit of claim 1, in combination with a plurality of other power supply units each of which also has a respective power input, power output, historic maximum power draw memory, update logic, and recovery current limiting logic, wherein the power supply units draw power from a power infrastructure which has a maximum rated capacity, wherein each power supply unit has a respective rated maximum draw, wherein the sum of the power supply unit rated maximum draws exceeds the maximum rated capacity of the power infrastructure, and wherein the sum of the power amounts drawn when each power supply unit limits recovery current based on its respective historic maximum power draw memory value does not exceed the maximum rated capacity of the power infrastructure.

5. The power supply unit of claim 1, wherein the recovery current limiting logic is activated in the power supply unit and the limited recovery current begins to flow quickly enough after the interruption of power starts to prevent a loss of data in a digital device that is powered by the power supply unit.

6. The power supply unit of claim 1, wherein the recovery current limiting logic permits limited recovery current to flow from the power infrastructure through the PSU in a stepped manner, namely, at a first power rate for a first time period and then at a second and greater power rate for a subsequent second time period.

7. A power supply system which dynamically limits total recovery current, comprising:

at least one power supply unit (PSU), the PSU comprising;

a power input;

a power output;

a resettable period timer having a full period of predetermined length;

a historic maximum power draw register which in operation represents the maximum power drawn by the PSU from a power infrastructure during a recent period;

a present period maximum power draw register which in operation represents the maximum power drawn by the PSU from the power infrastructure after a most recent update to the historic maximum power draw register;

one or more register update logics which in operation (a) collectively monitor an input power level at the PSU power input or an output load at the PSU power output or both to determine a level of power drawn by the PSU from a power infrastructure, and update the present period maximum power draw register based on the monitored power level, (b) update the historic maximum power draw register to match the monitored power level and reset the period timer when the monitored power level exceeds the historic maximum power draw register, and (c) reset the period timer and update the historic maximum power draw register to match the present period maximum power draw register after the historic maximum power draw register exceeds the present period maximum power draw register; and

a recovery current limiting logic which in operation after an interruption of power to the PSU permits a recovery current to flow from the power infrastructure through the PSU while limiting the recovery current based on the historic maximum power draw register.

8. The power supply system of claim 7, wherein the PSU is configured to operate differently depending on the length of the power interruption, in that the recovery current limiting logic operates when the length of the power interruption is less than a predetermined value X, but when the length of the power interruption is greater than X the PSU performs a soft start without operating the recovery current limiting logic.

9. The power supply system of claim 7, wherein the recovery current limiting logic is activated in the PSU only when the interruption of power to the PSU lasts for less than X milliseconds, where X is a value such that the power system can switch from main power to battery power through the PSU in less than X milliseconds without causing a loss of data in a digital device that is powered by the PSU.

10. The power supply system of claim 7, wherein the recovery current limiting logic begins permitting the limited recovery current to flow from the power infrastructure through the PSU within less than 100 milliseconds after the interruption of power begins.

11. The power supply system of claim 7, wherein the recovery current limiting logic permits limited recovery current to flow from the power infrastructure through the PSU at a plurality of ramped power rates.

12. The power supply system of claim 7, wherein the power supply system comprises at least ten thousand PSUs, each PSU comprising a respective resettable period timer, a respective historic maximum power draw register, a respective present period maximum power draw register, one or more respective register update logics, and a respective recovery current limiting logic.

13. The power supply system of claim 7, wherein the power supply system comprises the power infrastructure, wherein the power infrastructure provides power to servers in at least a portion of a datacenter, and wherein the power supply system comprises at least one thousand PSUs that are connected to the power infrastructure to power the servers, each PSU comprising a respective resettable period timer, a respective historic maximum power draw register, a respective present period maximum power draw register, one or more respective register update logics, and a respective recovery current limiting logic.

14. A method of dynamically limiting total recovery current in a power infrastructure, comprising:

monitoring an input power level at each of a plurality of power supply units (PSUs) which are electrically connected to the power infrastructure;

periodically calculating for each of the PSUs a historic power usage level over a recent time period which has a predetermined length; and

after an interruption of power to one or more of the PSUs, permitting recovery currents to flow through the power infrastructure to recovering PSUs while limiting the recovery currents based on the respective historic power usage levels of the recovering PSUs.

15. The method of claim 14, wherein:

each of the PSUs has a respective maximum continuous output wattage rating and a corresponding maximum continuous draw;

the power infrastructure has a recovery power load rating;

the sum of maximum continuous draws of the PSUs connected to the power infrastructure exceeds the recovery power load rating of the power infrastructure; and

the sum of the historic power usage levels of the PSUs connected to the power infrastructure does not exceed the recovery power load rating of the power infrastructure.

16. The method of claim 15, wherein the sum of maximum continuous draws of the PSUs connected to the power infrastructure is at least 1.5 times the recovery power load rating of the power infrastructure.

17. The method of claim 15, wherein the sum of maximum continuous draws of the PSUs connected to the power infrastructure is at least four times the recovery power load rating of the power infrastructure.

18. The method of claim 14, wherein limiting the recovery currents based on the respective historic power usage levels of the recovering PSUs comprises a PSU limiting its own recovery current to a value which is between 130% and 160% of the most recently calculated historic power usage level of the PSU.

19. The method of claim 14, wherein a recent time period which is used in periodically calculating a historic power usage level for a PSU has a predetermined length in the range from 30 to 90 minutes.

20. The method of claim 14, further comprising failing over from M PSUs to N PSUs, where N is less than M, and wherein permitting recovery currents to flow through the power infrastructure to recovering PSUs comprises allowing at least one of the N PSUs to draw a recovery current which exceeds that PSU'"'"'s historic power usage level, and wherein limiting the recovery currents based on the respective historic power usage levels of the recovering PSUs comprises limiting the recovery currents to the N PSUs to yield a total recovery current which does not exceed the total historic power usage levels of the M PSUs.