Compact dynamic phase angle regulators

• US 9,197,065 B2
• Filed: 12/06/2012
• Issued: 11/24/2015
• Est. Priority Date: 12/06/2011
• Status: Active Grant

• Current Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Original Assignee: Varentec Incorporated (KOCH Industries Incorporated)
• Inventors: Divan, Deepakraj M., Prasai, Anish
• Primary Examiner(s): Tran, Thienvu
• Assistant Examiner(s): Comber, Kevin J
• Application Number:
  US13/707,558
• Publication Number:
  US 20130140903A1
• Time in Patent Office: 1,083 Days
• Field of Search: 307/43, 307/45, 307/82, 307/113
• US Class Current: 1/1
• CPC Class Codes: H02J 3/01 Arrangements for reducing harmonics or ripples
• CPC Class Codes: H02J 3/1878 using tap changing or phase shifting transformers
• CPC Class Codes: Y02E 40/30 Reactive power compensation

Abstract

Compact dynamic Phase Angle Regulators (CD-PARs) are provided. A Compact Dynamic Phase Angle Regulator (CD-PAR) is a stand-alone device that regulates phase angle through a single transformer. A CD-PAR has no external energy source, uses low-rating devices, and can be isolated from a fault in the grid. A CD-PAR may be implemented in a single-phase or in a three-phase configuration, but the operation of a CD-PAR cross-couples all three phases. A CD-PAR controls both the real and the reactive power flow between two AC sources having the same frequency by inserting a voltage with controllable magnitude and phase. A CD-PAR may be implemented in either a buck configuration or a boost configuration.

Claims

1. A system for controlling active and reactive power flows between a first AC source and a second AC source, comprising:

a transformer comprising a first set of windings and a second set of windings, each of the first set of windings coupled to a line-line voltage, and the center point of each of the second set of windings coupled to a line-neutral voltage; and

a set of AC/AC converter coupled to the second set of windings, each of the set of AC/AC converters inserting a voltage to the corresponding line-neutral voltage.

2. The system of claim 1, wherein the transformer is a three-phase transformer and the first set of windings are connected in a delta configuration.

3. The system of claim 1, wherein the transformer is a single-phase transformer.

4. The system of claim 1, wherein the set of AC/AC converters comprises a buck converter.

5. The system of claim 3, wherein the buck converter comprises an output filter inductor.

6. The system of claim 1, wherein the set of AC/AC converters comprises a boost converter comprising a boost inductor.

7. The system of claim 5, wherein the boost inductor is the leakage inductance of the transformer.

8. The system of claim 1, wherein the set of AC/AC converters comprises a set of switches, further comprising a control module, wherein the control module generates a set of switching pulses to modulate the set of switches.

9. The system of claim 8, wherein the set of switching pulses comprise a constant component to generate a second voltage in quadrature with the line-neutral voltage, the second voltage being proportionate to the line-line voltage.

10. The system of claim 9, wherein the set of switching pulses comprise an even harmonic component to generate a third voltage in phase with the line-neutral voltage.

11. The system of claim 10, wherein the even harmonic is a second harmonic.

12. The system of claim 1, further comprising a hybrid active filter comprising an inductor and a capacitor resonating at a triplen harmonic, the hybrid active filter blocking the triplen harmonic.

13. The system of claim 11, further comprising a set of bypass switches, each of the set of bypass switches coupled across an AC/AC converter of the set of AC/AC converters.

14. The system of claim 1, further comprising an AC snubber.

15. The system of claim 1, wherein each of the AC/AC converters further comprises an output filter.