Direct-Coupled IT Load

• US 20090021078A1
• Filed: 07/18/2007
• Published: 01/22/2009
• Est. Priority Date: 07/18/2007
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Exaflop LLC (Alphabet Inc.)
• Inventors: Krieger, Ken, Hamburgen, William, Carlson, Andrew B., Whitted, William H., Clidaras, Jimmy, Sykora, Montgomery, Corhodzic, Selver, Beaty, Donald L., Aigner, Gerald
• Granted Patent: US 8,080,900 B2
• Time in Patent Office: Days
• US Class Current: 307/67
• CPC Class Codes: G06F 1/263 Arrangements for using multiple switchable power supplies, e.g. battery and AC G06F1/30 takes precedence
• CPC Class Codes: G06F 1/30 Means for acting in the event of power-supply failure or interruption, e.g. power-supply fluctuations for resetting only G06F1/24
• CPC Class Codes: H02J 1/001 Hot plugging or unplugging of load or power modules to or from power distribution networks
• CPC Class Codes: H02J 1/14 Balancing the load in a network
• CPC Class Codes: H02J 9/062 for AC powered loads
• CPC Class Codes: H02M 3/335 using semiconductor devices only
• CPC Class Codes: Y02B 10/70 Hybrid systems, e.g. uninterruptible or back-up power supplies integrating renewable energies

Abstract

Apparatus and associated method and computer program products involve a highly efficient uninterruptible power distribution architecture to support modular processing units. As an illustrative example, a modular processing unit includes an integrated uninterruptible power system in which a PFC-boost AC-to-DC conversion occurs between the utility AC grid and the processing circuit (e.g., microprocessor) loads. In an illustrative data center facility, a power distribution architecture includes a modular array of rack-mountable processing units, each of which has processing circuitry to handle network-related processing tasks. Associated with each modular processing unit is an integrated uninterruptible power supply (UPS) to supply operating power to the network processing circuitry. Each UPS includes a battery selectively connectable across a DC bus, and a AC-to-DC rectifier that converts an AC input voltage to a single output voltage on the DC bus. The regulated DC bus voltage may be close to the battery'"'"'s fully charged voltage.

Claims

1. A power distribution system for a data center, the system comprising:

a DC load comprising at least one digital processor operative to process data received over a network;

a DC bus configured to deliver operating power to the DC load, the power being received from a power source connected across the DC bus; and

an uninterruptible power supply (UPS) integrated with the DC load, the UPS comprising;

a battery circuit configured to operatively connect a battery across the DC bus during a fault condition in which an AC input voltage signal falls outside of a normal operating range, wherein the AC input voltage signal originates at a rotating AC generator;

an AC-to-DC rectification stage comprising an AC-to-DC conversion circuit configured to receive a substantially unconditioned AC input voltage and convert the AC input voltage signal to a single DC output voltage signal across the DC bus when the AC input voltage signal is within the normal operating range, wherein the AC-to-DC conversion circuit is configured to regulate the DC output voltage signal to a voltage level above and substantially near a maximum nominal charge voltage of the battery; and

a controller configured to selectively activate the AC-to-DC conversion circuit to resume supplying operating power to the DC load in response to a signal that indicates that the AC input voltage signal has returned to the normal operating range.

2. The system of claim 1, wherein the controller further controls a switch to selectively connect the battery across the DC bus.

3. The system of claim 1, wherein the battery comprises one or more cells electrically connected in series.

4. The system of claim 1, wherein the battery comprises one or more cells electrically connected in parallel.

5. The system of claim 1, wherein the AC input voltage signal is originated from one or more electric generator types selected from the group consisting of:

a generator in an electric utility plant;

a gas turbine;

a steam turbine; and

, a fuel-powered motor-generator.

6. The system of claim 1, wherein the AC input voltage signal comprises a phase voltage signal and a neutral signal from a three phase AC system.

7. The system of claim 1, wherein the AC input voltage has an r.m.s. value of about 208 Volts to about 277 Volts.

8. The system of claim 1, wherein the AC input voltage has an r.m.s. value between about 85 Volts and at least about 480 Volts.

9. The system of claim 1, wherein the AC input voltage substantially comprises a sinusoidal waveform at frequency of between about 45 Hz and at least about 500 Hertz.

10. The system of claim 1, wherein the AC input voltage is connected to WYE-connected voltage source.

11. The system of claim 1, wherein a cell in the battery comprises a battery chemistry selected from the group consisting of:

lead acid;

nickel metal hydride;

nickel cadmium;

alkaline; and

, lithium ion.

12. The system of claim 1, further comprising a charger configured to charge the battery through a path connected across the DC bus.

13. The system of claim 1, wherein the single DC bus voltage is less than about 26 Volts.

14. The system of claim 1, wherein the single DC bus voltage is between about 110 Volts and about 15 Volts.

15. The system of claim 1, wherein the single DC bus voltage is about 13.65 Volts.

16. The system of claim 1, wherein the AC-to-DC conversion circuit regulates the DC output voltage signal to approximately 1 Volt above the maximum nominal charge voltage of the battery.

17. The system of claim 1, wherein the DC bus voltage provides sufficient voltage for a linear regulator connected in series with the battery across the DC bus to trickle charge the battery to a fully charged state according to battery specifications.

18. The system of claim 1, wherein the DC bus comprises a first electrical path at a first voltage, and further comprises a second electrical path at a second voltage.

19. The system of claim 1, wherein one of the first and second voltages is substantially at a ground reference potential.

20. The system of claim 1, wherein the system has only one rectification circuit configured to convert an AC waveform to a DC waveform.

21. The system of claim 1, wherein a first terminal of the battery is configured to connect directly to a first rail of the DC bus, and the second terminal of the battery is selectively connected to a second rail of the DC bus.

22. The system of claim 1, further comprising a data store, wherein the AC-to-DC converter resumes regulating the DC output voltage signal a delay time after the at least one processor receives a signal indicative of the removal of the fault in the AC voltage input signal, said delay time corresponding to a delay time parameter in the data store.

23. The system of claim 22, wherein one of the at least one digital processors determines the stored delay time parameter.

24. The system of claim 22, wherein the stored delay time parameter comprises a pseudo-randomly generated value.

25. The system of claim 1, wherein the DC load, the DC bus, and the AC-to-DC rectification stage are all included on a modular base configured to be supported in one of a plurality of positions on a rack mounting structure, said base for mounting in any available one of a plurality of positions in a rack or frame.

26. The system of claim 1, wherein the DC load comprises at least one member of the group consisting of:

a central processing unit;

a data storage device;

a math coprocessor; and

, a digital signal processor.

27. The system of claim 26, further comprising at least one DC-DC converter configured to convert a voltage supplied on the DC bus to at least one further DC voltage.

28. The system of claim 27, wherein one or more of the at least one further DC voltage is approximately the voltage of a member of the group consisting of:

−

5;

1;

3;

3.3;

5;

7.5;

10;

about 18-20; and

, about 20-26 Volts.

29. The system of claim 27, wherein the one or more of the at least one DC-DC converters is configured to provide an improved output impedance.

30. The system of claim 27, wherein the one or more of the at least one DC-DC converters is configured to filter noise from the voltage supplied on the DC bus.

31. The system of claim 1, wherein the AC input voltage signal is originated from one or more sources of electric energy selected from the group consisting of:

at least one solar panel;

at least one wind turbine; and

, at least one flywheel.

32. The system of claim 1, wherein the DC load further comprises one or more information-containing signals transmitted to a load external to the DC load.

33. The system of claim 1 further comprising at least 10 instantiations of the DC load connected in parallel to the AC input voltage.

34. A DC load for use in a data center, the load comprising:

a motherboard including at least one digital processor operative to process data received over a network;

a DC bus configured to deliver operating power to the motherboard, the power being received from a power source connected across the DC bus; and

an uninterruptible power supply (UPS) integrated with the DC load, the UPS comprising;

a battery circuit configured to operatively connect a battery across the DC bus during a fault condition in which an AC input voltage signal falls outside of a normal operating range;

an AC-to-DC rectification stage comprising a PFC-boost AC-to-DC conversion circuit configured to convert a substantially unconditioned AC input voltage signal to a single DC output voltage signal across the DC bus when the AC input voltage signal is within the normal operating range, wherein the AC-to-DC conversion circuit is configured to regulate the DC output voltage signal to a voltage level above and substantially near a maximum nominal charge voltage of the battery; and

a controller configured to selectively activate the AC-to-DC conversion circuit to resume supplying operating power to the DC load in response to a signal that indicates that the AC input voltage signal has returned to the normal operating range.

35. The DC load of claim 34, further comprising at least one point-of-load DC-DC converter on the motherboard, configured to receive DC voltage from the DC bus and provide conditioned DC voltage to an operating circuit on the motherboard.

36. The DC load of claim 35 wherein one or more of the at least one point-of-load DC-DC converters is configured to provide an improved DC output impedance.

37. The DC load of claim 34 wherein the PFC-boost AC-to-DC conversion circuit is of a continuous conduction mode (CCM) type including average current mode control (ACMC).

38. The DC load of claim 34 wherein the PFC-boost AC-to-DC conversion circuit is of a critical conduction mode (CRM) type.

39. The DC load of claim 34 connected in a data center further comprising 50 or more of the DC loads of claim 34 connected in parallel to the AC input voltage.

41. The method of claim 38, further comprising continuously providing operating power to operate the DC load substantially without interruption for at least 10 seconds.

42. The method of claim 38, wherein the set point voltage is substantially close to a nominal fully charged voltage for the back-up battery.

43. The method of claim 38, further comprising dynamically selecting the set point voltage based on operating conditions of the back-up battery.

44. The method of claim 38, further comprising detecting a fault condition of the AC input voltage signal.

40. A method of providing uninterruptible power to at a motherboard in a data center, the method comprising:

connecting a DC bus to supply a single DC voltage to at least one DC load, each DC load comprising at least one digital processor;

operating a PFC-boost AC-to-DC converter when an AC input voltage signal from the electric utility grid is within a normal voltage range, the operating step comprising;

converting the AC input voltage signal to a DC voltage on the DC bus, wherein the converting step comprises the only AC-to-DC rectification of electric power generated by the electric utility grid and delivered to the DC load;

regulating the converted DC bus voltage to a set point voltage, the set point voltage being substantially close to a voltage in a nominal voltage range for a back-up battery;

in response to detecting a fault condition of the AC input voltage signal, connecting a battery circuit directly across the DC bus to enable the back-up battery in the battery circuit to provide operating power to the DC load such that the DC load continues to operate for a period of time after detecting the fault.

45. A method of providing uninterruptible power to a substantial portion of motherboards operating in a data center, the method comprising:

connecting a substantially unconditioned AC supply voltage to at least 50 loads, each load comprising a PFC-boost AC-to-DC converter, the converter regulating a converted DC bus voltage to a set point voltage, the set point voltage being substantially close to a voltage in a nominal voltage range for a back-up battery;

detecting a fault condition of the AC input voltage signal;

in response to detecting a fault condition of the AC input voltage signal, connecting a battery circuit directly across the DC bus to enable the back-up 11 battery in the battery circuit to provide operating power to the DC load such that the DC load continues to operate for a period of time after detecting the fault.

46. The method of claim 45 in which a one or more of the at least 50 loads further comprise a point-of-load DC-DC converter supplying a processor with filtered DC voltage.

47. The method of claim 45 in which a one or more of the at least 50 loads further comprise a point-of-load DC-DC converter supplying a processor with improved-output-impedance DC voltage.

48. The method of claim 45 wherein the PFC-boost AC-to-DC converter is of a continuous conduction mode (CCM) type including average current mode control (ACMC).

49. The method of claim 45 wherein the PFC-boost AC-to-DC converter is of a critical conduction mode (CRM) type.

50. The method of claim 45 further comprising presenting a combined power factor of the at least 50 loads to the AC supply voltage, the combined power factor being at least 0.95.

51. The method of claim 45 further comprising presenting a combined power factor of the at least 50 loads to the AC supply voltage, the combined power factor being at least 0.98.

52. The method of claim 45 further comprising presenting a combined power factor of the at least 50 loads to the AC supply voltage, the combined power factor being at least 0.98 leading.