Granted Patent B2

US 9,184,652 · App. 14/011,220 · Granted Nov 10, 2015

Abstract

Claims (29)

1. A method for reducing harmonic distortion, comprising:

determining an inverter output current waveform characterized by notching proximate respective zero crossings, wherein each notch corresponds to distortion associated with operation of an inverter;

determining a plurality of harmonic components of the inverter output current waveform, at least some harmonic components of the plurality of harmonic components resulting from the distortion;

determining, based on the plurality of harmonic components, a plurality of harmonic compensation components; and

generating, by an inverter coupled to a distributed generator having at least one energy generator module, a compensating current comprising the plurality of harmonic compensation components.

2. The method of claim 1 , wherein the inverter output current waveform is determined by analytical modeling based on an output current from one or more inverters.

3. The method of claim 1 , wherein the inverter output current waveform is empirically determined by measuring an output current from one or more inverters.

4. The method of claim 1 , wherein an amplitude of each harmonic component of the plurality of harmonic components is analytically calculated based on the inverter output current waveform.

5. The method of claim 1 , wherein an amplitude of each harmonic component of the plurality of harmonic components is measured for determining the plurality of harmonic compensation components.

6. The method of claim 1 , wherein amplitude and phase of each harmonic compensation component of the plurality of harmonic compensation components are manually tuned to reduce a corresponding harmonic component.

7. The method of claim 1 , further comprising storing the plurality of harmonic compensation components in the inverter coupled to the distributed generator.

8. The method of claim 7 , wherein the plurality of harmonic compensation components are stored in a look-up table.

9. The method of claim 7 , wherein the compensating current is superimposed on a current waveform, and wherein the current waveform is at a fundamental frequency of an AC line coupled to an output of the inverter coupled to the distributed generator.

10. The method of claim 1 , wherein the plurality of harmonic components are 23 rd -39 th order harmonics.

11. An apparatus for reducing harmonic distortion, comprising:

an inverter coupled to a distributed generator, wherein the inverter comprises:

a harmonic reduction module for storing a plurality of harmonic compensation components,

wherein the plurality of harmonic compensation components are determined based on a plurality of harmonic components of an inverter output current waveform characterized by notching proximate respective zero crossings such that each notch corresponds to distortion associated with operation of an inverter, and

wherein at least some harmonic components of the plurality of harmonic components result from the distortion; and

a power conversion module for generating a compensating current comprising the plurality of harmonic compensation components.

12. The apparatus of claim 11 , wherein the inverter output current waveform is determined by analytical modeling based on an output current from one or more inverters.

13. The apparatus of claim 11 , wherein the inverter output current waveform is empirically determined by measuring an output current from one or more inverters.

14. The apparatus of claim 11 , wherein an amplitude of each harmonic component of the plurality of harmonic components is analytically calculated based on the inverter output current waveform.

15. The apparatus of claim 11 , wherein an amplitude of each harmonic component of the plurality of harmonic components is measured for determining the plurality of harmonic compensation components.

16. The apparatus of claim 11 , wherein amplitude and phase of each harmonic compensation component of the plurality of harmonic compensation components are manually tuned to reduce a corresponding harmonic component.

17. The apparatus of claim 11 , wherein the harmonic reduction module stores the plurality of harmonic compensation components.

18. The apparatus of claim 17 , wherein the harmonic reduction module comprises a look-up table for storing the plurality of harmonic compensation components.

19. The apparatus of claim 18 , wherein the compensating current is superimposed on a current waveform, and wherein the current waveform is at a fundamental frequency of an AC line coupled to an output of the power conversion module.

20. The apparatus of claim 11 , wherein the plurality of harmonic components are 23 rd -39 th order harmonics.

Assignments (8)