Harmonic control and regulation system for harmonic neutralized frequency changer

• US 7,388,766 B2
• Filed: 08/26/2004
• Issued: 06/17/2008
• Est. Priority Date: 08/26/2004
• Status: Active Grant

• Current Assignee: Curtiss-Wright Electro-Mechanical Corporation (Curtiss-Wright Corporation)
• Original Assignee: Curtiss-Wright Electro-Mechanical Corporation (Curtiss-Wright Corporation)
• Inventors: Baumgart, Gary E., Sen, Kalyan K.
• Primary Examiner(s): Patel; Rajnikant B.
• Application Number:
  US10/928,657
• Publication Number:
  US 20060044847A1
• Time in Patent Office: 1,391 Days
• Field of Search: 363 34- 44, 363/71, 363/97, 363/98, 363/78, 363/80, 363/89, 363/159, 363/157, 363/160, 363/65, 363/163, 323205-210, 327552-559
• US Class Current: 363/40
• CPC Class Codes: H02J 3/1814 wherein al least one reactive element is actively controlled by a bridge converter, e.g. unified power flow controllers [UPFC]
• CPC Class Codes: H02J 3/1857 wherein such bridge converter is a multilevel converter
• CPC Class Codes: H02M 1/12 Arrangements for reducing harmonics from ac input or output
• CPC Class Codes: H02M 5/45 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: Y02E 40/10 Flexible AC transmission systems [FACTS]
• CPC Class Codes: Y02E 40/20 Active power filtering [APF]

Abstract

A control and regulation system for use with a harmonic neutralization frequency changer system. In the generalized frequency changer system, a direct converter frequency changer is used to convert bulk power, but unwanted harmonics are introduced. Input and output power distortion is monitored by a control system, and groups of high performance inverters inject shunt/series harmonic currents/voltages into a specially designed transformer to neutralize the power distortion to a specific acceptable level. Two control strategies are used including one that is based on discrete narrow band harmonic regulation and another that is based on wide band harmonic control. Each of these control strategies can be used at the input and/or output of the frequency changer and can be injected using shunt-current and series-voltage schemes.

Claims

1. An inverter controller subsystem for a harmonic neutralization frequency changer system;

comprising;

a frequency changer;

a high bandwidth inverter;

an inverter controller adapted to calculate harmonics at the frequency changer and control the high bandwidth inverter to generate harmonic cancellation signals, wherein said inverter controller samples the frequency changer signals in a stationary reference plane, converts the sampled signals into a rotating reference frame, generates harmonic neutralization signals, and then converts the harmonic neutralization signals back into the stationary reference plane; and

an injection transformer for injecting said calculated harmonic neutralization signals into said frequency changer system.

2. The system of claim 1, wherein said inverter controller calculates harmonic neutralization signals based on a discrete narrow band calculation methodology.

3. The system of claim 2, wherein said harmonic neutralization signals are current signals.

4. The system of claim 2, wherein said harmonic neutralization signals are voltage signals.

5. The system of claim 2, wherein said narrow band calculations include n subcircuits, where n is calculated based upon the topology of the frequency changer.

6. The system of claim 2, further comprising a second injection transformer, wherein said inverter controller samples both input and output signals from the frequency changer and calculates and injects harmonic neutralization signals at the input and the output of the frequency changer.

7. The system of claim 1, wherein said inverter controller calculates harmonic neutralization signals based on a wide band calculation methodology.

8. The system of claim 7, wherein said harmonic neutralization signals are current signals.

9. The system of claim 7, wherein said harmonic neutralization signals are voltage signals.

10. The system of claim 7, wherein said inverter controller includes a filter to remove high frequency harmonics.

11. The system of claim 7, further comprising a second injection transformer, wherein said inverter controller samples both input and output signals from the frequency changer and calculates and injects harmonic neutralization signals at the input and the output of the frequency changer.

12. A power converter system, comprising:

a direct conversion frequency changer including an input and an output, the frequency changer adapted to accept an input voltage at an input frequency at the input and deliver an output voltage at an output frequency at the output;

an input high bandwidth inverter;

an output high bandwidth inverter;

an inverter controller adapted to calculate harmonics at the input and output of the frequency changer and control the input and output high bandwidth inverters to generate input and output harmonic cancellation signals, wherein said inverter controller samples the frequency changer signals in a stationary reference plane, converts the sampled signals into a rotating reference frame, generates harmonic neutralization signals, and then converts the harmonic neutralization signals back into the stationary reference plane;

an input harmonic injection transformer connected to the input inverter and the input of the frequency changer to inject said input harmonic neutralization signals; and

an output harmonic injection transformer connected to the output inverter and the output of the frequency changer to inject said output harmonic neutralization signals.

13. The system of claim 12, wherein said inverter controller calculates harmonic neutralization signals based on a discrete narrow band calculation methodology.

14. The system of claim 13, wherein said harmonic neutralization signals are current signals.

15. The system of claim 13, wherein said harmonic neutralization signals are voltage signals.

16. The system of claim 13, wherein said narrow band calculations include n subcircuits, where n is calculated based upon the topology of the frequency changer.

17. The system of claim 13, further comprising a second injection transformer, wherein said inverter controller samples both input and output signals from the frequency changer and calculates and injects harmonic neutralization signals at the input and the output of the frequency changer.

18. The system of claim 12, wherein said inverter controller calculates harmonic neutralization signals based on a wide band calculation methodology.

19. The system of claim 18, wherein said harmonic neutralization signals are current signals.

20. The system of claim 18, wherein said harmonic neutralization signals are voltage signals.