AC power monitoring and parameter determination

Patent metadata

Field	Value
Publication number	US-9548650-B1
Application number	US-201113303089-A
Country	US
Kind code	B1
Filing date	Nov 22, 2011
Priority date	Nov 22, 2011
Publication date	Jan 17, 2017
Grant date	Jan 17, 2017

Abstract

Devices and methods for monitoring and determining alternating current (AC) power system parameters are provided. In some implementations, the device can include a processor; and at least one non-transitory computer-readable medium storing computer-executable instructions for implementing a number of components. The components include a monitor configured to: sense an AC line voltage signal and an AC current voltage signal; filter the AC line voltage signal; calculate average AC line voltage and current values based, at least, on a DC voltage and current values corresponding to the AC line voltage and current signals, respectively; determine fundamental AC line voltage and current signals based, at least, on zero crossings of the respective average AC line voltage value and the average AC line current value; and determine one or more AC power system parameters based, at least, on the fundamental AC line voltage signal and the fundamental AC line current signal.

First claim

What is claimed is:

1. A device, comprising:
at least one processor; and
at least one non-transitory computer-readable medium communicatively coupled to the at least one processor, the at least one non-transitory computer-readable medium having stored therein computer-executable instructions for implementing:
an alternating current (AC) power system monitor configured to:
sense an AC line voltage signal provided by a power system;
filter the AC line voltage signal to remove one or more harmonic frequencies of the AC line voltage signal;
determine one or more zero crossings of the filtered AC line voltage signal;
determine a direct current (DC) voltage value for the AC line voltage signal provided by the power system based, at least in part, on the filtered AC line voltage signal and the one or more zero crossings;
determine an active power voltage value for the AC line voltage signal provided by the power system and a power factor voltage value for the AC line voltage signal provided by the power system based, at least in part, on the determined DC voltage value;
determine a fundamental AC line voltage signal for the AC line voltage signal provided by the power system based, at least in part, on a sum of an average of the active power voltage value for the AC line voltage signal provided by the power system and an average of the power factor voltage value for the AC line voltage signal provided by the power system;
determine one or more AC power system parameters for the AC line voltage signal provided by the power system based, at least in part, on the determined fundamental AC line voltage signal; and
adjust AC power provided by the power system based, at least in part, on the one or more determined AC power system parameters.

2. The device of claim 1 , wherein at least one of the one or more AC power system parameters is a total harmonic distortion (THD) of an AC power system.

3. The device of claim 2 , wherein the AC power system monitor is configured to determine the THD based on the fundamental AC line voltage signal and a fundamental AC line current signal.

4. The device of claim 1 , wherein at least one of the one or more AC power system parameters is a power factor of an AC power system.

5. The device of claim 4 , wherein the AC power system monitor is further configured to determine the power factor based on an angle between the fundamental AC line voltage signal and a fundamental AC line current signal.

6. The device of claim 4 , wherein the power factor is a displacement power factor.

7. The device of claim 6 , wherein the power factor is a function of the displacement power factor, the fundamental AC line voltage signal and a fundamental AC line current signal.

8. The device of claim 1 , wherein the AC power system monitor is configured to filter the one or more harmonic frequencies of the AC line voltage signal via a low pass filter.

9. The device of claim 1 , wherein the AC power system monitor is further configured to re-determine the active power voltage value and the power factor voltage value every half AC cycle.

10. A method, comprising:
employing at least one processor executing computer-executable instructions embodied on at least one non-transitory computer-readable medium to perform operations comprising:
sensing an AC line voltage signal provided by a power system;
filtering the AC line voltage signal to remove one or more harmonic frequencies of the AC line voltage signal;
determining one or more zero crossings of the filtered AC line voltage signal;
determining a direct current (DC) voltage value for the AC line voltage signal provided by the power system based, at least in part, on the filtered AC line voltage signal and the one or more zero crossings;
determining an active power voltage value for the AC line voltage signal provided by the power system and a power factor voltage value for the AC line voltage signal provided by the power system based, at least in part, on the determined DC voltage value;
determining a fundamental AC line voltage signal for the AC line voltage signal provided by the power system based, at least in part, on a sum of an average of the active power voltage value for the AC line voltage signal provided by the power system and an average of the power factor voltage value for the AC line voltage signal provided by the power system;
determining one or more AC power system parameters for the AC line voltage signal provided by the power system based, at least in part, on the determined fundamental AC line voltage signal; and
adjusting AC power provided by the power system based, at least in part, on the one or more determined AC power system parameters.

11. The method of claim 10 , wherein determining the one or more AC power system parameters comprises determining a total harmonic distortion (THD) of an AC power system.

12. The method of claim 11 , wherein the THD is based on the fundamental AC line voltage signal and a fundamental AC line current signal.

13. The method of claim 10 , wherein determining the one or more AC power system parameters comprises determining a power factor of an AC power system.

14. The method of claim 13 , wherein determining the power factor of an AC power system is based on an angle between the fundamental AC line voltage signal and a fundamental AC line current signal.

15. The method of claim 13 , wherein the power factor is a displacement power factor.

16. The method of claim 15 , wherein the power factor is a function of the displacement power factor, the fundamental AC line voltage signal and a fundamental AC line current signal.

17. The method of claim 10 , wherein filtering the AC line voltage signal and removing one or more harmonic frequencies of the AC line voltage signal is performed via a low pass filter.

18. The method of claim 10 , further comprising re-determining the active power voltage value and the power factor voltage value every half AC cycle.

19. The method of claim 10 , further comprising controlling power provided to one or more servers based, at least, on the one or more AC system parameters.

20. The method of claim 10 , further comprising generating one or more power control policy decisions for one or more servers based, at least, on the one or more AC system parameters.

Assignees

• Kim Sangsun
• Lipiansky Eduardo Marcelo
• Google Inc

Inventors

• Kim Sangsun
• Lipiansky Eduardo Marcelo

Classifications

• G01R21/006

  Measuring power factor · CPC title

• H02J3/00

  Circuit arrangements for AC mains or AC distribution networks · CPC title

• G01R19/2513

  Arrangements for monitoring electric power systems, e.g. power lines or loads; Logging · CPC title

• G01R21/00

  Arrangements for measuring electric power or power factor (G01R7/12 takes precedence) · CPC title

• H02J3/01

  Arrangements for reducing harmonics or ripples · CPC title