Systems and methods for tuning the control of a shunt active power filter over a variable frequency

• US 9,225,172 B2
• Filed: 06/21/2013
• Issued: 12/29/2015
• Est. Priority Date: 06/21/2013
• Status: Active Grant

• Current Assignee: Hamilton Sundstrand Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Hamilton Sundstrand Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Blasko, Vladimir, Rodriguez, Fernando
• Primary Examiner(s): PATEL, RAJNIKANT B
• Application Number:
  US13/923,807
• Publication Number:
  US 20140376284A1
• Time in Patent Office: 921 Days
• Field of Search: 363 16- 20, 363 34- 41, 363/9, 363/97, 363/98, 307/64, 318/599, 318/696, 318/702
• US Class Current: 1/1
• CPC Class Codes: H02J 3/01 Arrangements for reducing harmonics or ripples
• CPC Class Codes: Y02E 40/20 Active power filtering [APF]

Abstract

Embodiments relate to systems and methods for tuning the control of a shunt active power filter over a variable frequency. In aspects, a shunt active power filter is provided to filter current harmonics from the output delivered to a dc load via a rectifier. The shunt active power filter control can be configured as a set of resonant regulators connected in a parallel configuration. Each of the resonant regulators can be tuned to dampen or eliminate a particular harmonic, such as the 5th, 7^th, 11^th, 13^th, 17^th or 19^th harmonics. The shunt active power filter can be configured to target those or other harmonics over a range of source voltage frequencies, such as 360-800 Hz. The harmonics can be tuned over that or other source frequency ranges by determining the root locus poles of the filter as a function of feedback loop gain.

Claims

1. A shunt active power filter system, comprising:

a first interface to a source power signal having a selectable frequency;

a set of resonant regulators coupled to the source power signal;

a second interface configured to couple an output power signal from the set of resonant regulators to a load;

a feedback loop having an input end coupled directly to the load indicating a selected frequency of the source power signal and an output end coupled directly an input of a gain tuning unit to be summed with a harmonic current (I_h), the feedback loop coupled between the source power signal and the set of resonant regulators, and the gain tuning unit disposed upstream from the resonant regulators and connected in series with the feedback loop and the load, the gain tuning unit generating a selectable gain value that is provided to the set of resonant regulators;

wherein the selectable gain value is selected to dampen a set of harmonics associated with the source power signal at the selected frequency of the source power signal indicated by the feedback loop based on a set of closed loop poles of the shunt active power filter system associated with the selected gain value.

2. The system of claim 1, wherein the source power signal comprises an alternating current signal.

3. The system of claim 2, wherein a frequency of the source power signal comprises a range of 360 to 800 Hz.

4. The system of claim 3, wherein the set of harmonics comprises at least a set of 5th, 7th, 11th, 13th, 17th, and 19th harmonics.

5. The system of claim 1, wherein the set of resonant regulators are connected in a parallel configuration.

6. The system of claim 1, wherein the load comprises a rectified load.

7. The system of claim 1, wherein the selectable gain value determines a rate of decay of the set of harmonics.

8. The system of claim 7, wherein the rate of decay is at least approximately equal to an inverse of the gain multiplied by a fundamental period of the source power signal.

9. A method of generating a power signal, comprising:

receiving a source power signal having a selectable frequency in a shunt active power filter;

coupling the source power signal to a set of resonant regulators;

coupling an output power signal from the set of resonant regulators to a load to generate a source current (I_s);

coupling the output power signal to the set of resonant regulators via a feedback loop having an input end coupled directly to the load to indicate a selected frequency of the source power signal and an output end coupled directly an input of a gain tuning unit to be summed with a harmonic current (I_h);

connecting a gain tuning unit upstream from the set of resonant regulators and in series with the feedback loop and the load, the gain tuning unit providing a selectable gain value to the set of resonant regulators;

selecting the frequency of the source power signal;

selecting the selectable gain value via the gain tuning unit to dampen a set of harmonics associated with the source power signal at the selected frequency indicated by the feedback loop based on a set of closed loop poles of the shunt active power filter associated with the selected gain value.

10. The method of claim 9, wherein the source power signal comprises an alternating current signal.

11. The method of claim 10, wherein a frequency of the source power signal comprises a range of 360 to 800 Hz.

12. The method of claim 11, wherein the set of harmonics comprises at least a set of 5th, 7th, 11th, 13th, 17th, and 19th harmonics.

13. The method of claim 9, wherein the set of resonant regulators are connected in a parallel configuration.

14. The method of claim 9, wherein the load comprises a rectified load.

15. The method of claim 9, wherein the selectable gain value determines a rate of decay of the set of harmonics.

16. The method of claim 15, wherein the rate of decay is at least approximately equal to an inverse of the gain multiplied by a fundamental period of the source power signal.