Smart-grid adaptive power management method and system with power factor optimization and total harmonic distortion reduction

• US 8,874,277 B2
• Filed: 09/15/2010
• Issued: 10/28/2014
• Est. Priority Date: 09/15/2009
• Status: Active Grant

• Current Assignee: Volta Energy, Inc.
• Original Assignee: Networked Power, Inc.
• Inventors: Kouroussis, Denis, Kulali, Emre
• Primary Examiner(s): Padmanabhan, Kavita
• Assistant Examiner(s): Everett, Christopher E
• Application Number:
  US12/883,065
• Publication Number:
  US 20110071695A1
• Time in Patent Office: 1,504 Days
• Field of Search: None
• US Class Current: 700/295
• CPC Class Codes: G05B 13/021 in which a variable is automatically adjusted to optimise the performance
• CPC Class Codes: G05B 15/02 electric
• CPC Class Codes: G05F 1/66 Regulating electric power
• CPC Class Codes: H02J 13/00034 the elements or equipment being or involving an electric power substation
• CPC Class Codes: H02J 2203/10 Power transmission or distribution systems management focussing at grid-level, e.g. load flow analysis, node profile computation, meshed network optimisation, active network management or spinning reserve management
• CPC Class Codes: H02J 3/01 Arrangements for reducing harmonics or ripples
• CPC Class Codes: H02J 3/144 Demand-response operation of the power transmission or distribution network
• CPC Class Codes: H02J 3/18 Arrangements for adjusting, eliminating or compensating reactive power in networks for adjustment of voltage H02J3/16
• CPC Class Codes: H02J 3/1892 the arrangements being an integral part of the load, e.g. a motor, or of its control circuit
• CPC Class Codes: H02M 1/4233 using a bridge converter comprising active switches
• CPC Class Codes: H02M 5/458 using semiconductor devices only
• 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
• CPC Class Codes: Y02B 70/3225 Demand response systems, e.g. load shedding, peak shaving
• CPC Class Codes: Y04S 20/222 Demand response systems, e.g. load shedding, peak shaving

Abstract

A method and system of power factor optimization and total harmonic distortion are provided under the premise of efficient power management and distribution on an electrical grid. The method and system include a novel optimization technique based on a novel current profiling methodology enabling real-time power management with power factor correction as a function of the optimization. The optimization can be performed under dynamic current constraints. When deployed on an electrical grid, the method and system can provide a new technique for power management targeting an efficiency of the electrical grid. The method and system can thus provide for reduced costs of energy production and reduced carbon emissions into the atmosphere.

Claims

1. A method of power factor correction in a power delivery system, comprising:

determining a total current requirement of at least one load coupled to, and drawing current from, a power supply with a known power limit and current limit;

determining an available excess current, wherein the available excess current is a current available beyond the total current requirement of the at least one load;

determining whether a new non-critical load has been introduced;

calculating a plurality of switching configurations that are each capable of switching current from the power supply to the at least one load and the non-critical load without exceeding the current limit of the power supply when a current requirement of the new non-critical load exceeds the available excess current, wherein each switching configuration of said plurality of switching configurations is associated with a power factor defined as the ratio of real power transferred to apparent power;

identifying an optimal switching configuration from among said plurality of switching configurations that will realize a highest power factor of said power factors associated with each of said plurality of switching configurations, wherein the highest power factor provides for a highest efficiency of the system from among said plurality of switching configurations; and

using said optimal switching configuration to switch current from the power supply to the at least one load and the non-critical load.

2. The method of claim 1, wherein calculating the plurality of switching configurations comprises referencing a power library comprising a plurality of current profiles of one or more loads.

3. The method of claim 2, wherein the plurality of current profiles in the power library includes a plurality of root-mean-square (RMS) current values.

4. The method of claim 2, wherein the plurality of current profiles in the power library includes a plurality of current waveforms.

5. The method of claim 2, wherein the plurality of current profiles in the power library includes a plurality of Fourier transform representations of a plurality of current waveforms.

6. The method of claim 1, wherein the total current requirement of the at least one load comprises a plurality of currents, each current having a current profile, wherein the current profile comprises information regarding a use pattern of a current of the plurality of currents.

7. The method of claim 1, wherein calculating the plurality of switching configurations includes referencing user defined constraints of a total current.

8. The method of claim 1, wherein calculating the plurality of switching configurations includes referencing user defined constraints of a current of at least one load.

9. The method of claim 1, further comprising determining a lowest possible current required to maintain the non-critical load in an operating condition.

10. The method of claim 9, wherein calculating the plurality of switching configurations includes calculating switching configurations that are capable of delivering current that meets or exceeds the lowest possible current required to maintain the non-critical load in an operating state, and wherein the plurality of calculated switching configurations from which the optimal switching configuration is identified only includes switching configurations calculated to be capable of both switching current from the power supply to the at least one load and the non-critical load without exceeding the current limit of the power supply and delivering current that meets or exceeds the lowest possible current required to maintain the non-critical load in an operating state.

11. An apparatus for power factor correction in a power delivery system, comprising:

a total current determining unit configured to determine a total current requirement of at least one load coupled to, and drawing current from, a power supply with a known power limit and current limit;

a current determining unit configured to determine an available excess current, wherein the available excess current is a current available beyond the total current requirement of the at least one load;

a non-critical load determining unit configured to determine whether a new non-critical load has been introduced; and

a calculating unit configured to calculate an optimal switching configuration to deliver current to the new non-critical load when a current requirement of the new non-critical load exceeds the available excess current, wherein the calculating unit is configured to calculate the optimal switching configuration by calculating a plurality of switching configurations that are each capable of switching current from the power supply to the at least one load and the non-critical load while not exceeding the current limit of the power supply, each switching configuration of said plurality of switching configurations associated with a power factor defined as the ratio of real power transferred to apparent power, and identifying which switching configuration from among the calculated plurality of switching configurations will realize a highest power factor of said power factors associated with each of said plurality of switching configurations, wherein the highest power factor provides for a highest efficiency of the system from among said plurality of switching configurations.

12. The apparatus of claim 11, wherein the calculating unit is further configured to reference a power library comprising a plurality of current profiles of one or more loads.

13. The apparatus of claim 12, wherein the plurality of current profiles in the power library includes root-mean-square (RMS) current values.

14. The apparatus of claim 12, wherein the plurality of current profiles in the power library includes a plurality of current waveforms.

15. The apparatus of claim 13, wherein the plurality of current profiles in the power library includes a plurality of Fourier transform representations of a plurality of current waveforms.

16. The apparatus of claim 11, wherein the total current requirement of the at least one load comprises a plurality of currents, each current having a current profile, wherein the current profile comprises information regarding a use pattern of the plurality of currents.

17. The apparatus of claim 11, wherein the calculating unit is further configured to reference user defined constraints of a total current.

18. The apparatus of claim 11, wherein the calculating unit is further configured to reference user defined constraints of a current of a load.

19. The apparatus of claim 11, wherein said current determining unit is further configured to determine a lowest possible current required to maintain the non-critical load in an operating state.

20. The apparatus of claim 19, wherein said calculating unit is further configured to:

calculate switching configurations that are capable of delivering current that meets or exceeds the lowest possible current required to maintain the non-critical load in an operating state; and

identify the optimal switching configuration from among the plurality of calculated switching configurations calculated to be capable of both switching current from the power supply to the at least one load and the non-critical load without exceeding the current limit of the power supply and delivering current that meets or exceeds the lowest possible current required to maintain the non-critical load in an operating state.

21. A method of power factor correction in a power delivery system, comprising:

determining a total current requirement of at least one load coupled to, and drawing current from, a power supply with a known power limit and current limit;

determining an available excess current, wherein the available excess current is a current available beyond the total current requirement of the at least one load;

determining whether a new non-critical load has been introduced;

determining whether a current requirement of the new non-critical load exceeds the available excess current;

when it is determined that the current requirement of the new non-critical load exceeds the available excess current, comparing a current requirement of the new non-critical load to a plurality of current profiles within a database to determine a plurality of switching configurations that are each capable of switching current from the power supply to the at least one load and the non-critical load while not exceeding the current limit of the power supply, wherein each switching configuration of said plurality of switching configurations is associated with a power factor defined as the ratio of real power transferred to apparent power;

determining an optimal switching configuration from among the plurality of switching configurations determined to be capable of switching current from the power supply to the at least one load and the non-critical load while not exceeding the current limit of the power supply, said optimal switching configuration being the switching configuration among the plurality of switching configurations that will realize a highest power factor of said power factors associated with each of said plurality of switching configurations, wherein the highest power factor provides for a highest efficiency of the system from among said plurality of switching configurations; and

using said optimal switching configuration to switch current from the power supply to the at least one load and the new non-critical load.

22. The method of claim 21, further comprising determining a lowest possible current required to maintain the non-critical load in an operating condition.

23. The method of claim 22, wherein the plurality of switching configurations from which the optimal switching configuration is determined is limited to switching configurations that are both capable of switching current from the power supply to the at least one load and the non-critical load while not exceeding the current limit of the power supply and delivering current that meets or exceeds a lowest possible current required to maintain the non-critical load in an operating condition.

24. An apparatus for power factor correction in a power delivery system, comprising:

means for determining a total current requirement of at least one load coupled to, and drawing current from, a power supply with a known power limit and current limit;

means for determining an available excess current, wherein the available excess current is a current available beyond the total current requirement of the at least one load;

means for determining whether a new non-critical load has been introduced;

means for determining whether a current requirement of the new non-critical load exceeds the available excess current;

means for calculating first and second switching configurations to deliver current to the new non-critical load when the current requirement of the new non-critical load exceeds the available excess current, wherein each of said first and second switching configurations is associated with a power factor defined as the ratio of real power transferred to apparent power;

means for determining which of said first and second switching configurations will realize a highest power factor of said power factors associated with each of said first and second switching configurations when configured to switch current from the power supply to the new non-critical load, wherein the highest power factor provides for a highest efficiency of the system from among said first and second switching configurations; and

means for switching current from the power supply to the at least one load and the new non-critical load using the switching configuration that is determined to realize the highest power factor.

25. The apparatus of claim 24, further comprising means for determining a lowest possible current required to maintain the non-critical load in an operating condition.

26. The apparatus of claim 25, wherein the first and second switching configurations calculated by said means for calculating are switching configurations that are each capable of delivering current t to the non-critical load that meets or exceeds the lowest possible current required to maintain the non-critical load in an operating condition and that are each capable of switching current from a power supply to the at least one load and the non-critical load without exceeding a current limit of the power supply.