US5068774A
Expired / Lapsed
US
⏱️ 0.0 years remaining
24-pulse hexagon-type AC/DC static converter
Assignee: Northrop Grumman Corp
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Filing: 1990-12-03
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Granted: 1991-11-26
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Expires: 2010-12-03
Abstract
Abstract An AC/DC or DC/AC converter includes a single hexagon transformer with each side connected to opposite polarity DC terminals through two pairs of SCR devices gated in sequence synchronously with the frequency of the AC lines, gating in a pair lagging gating of the next SCR device in the adjoining pair, to create a 24-pulse output, while minimizing AC line harmonic contents, especially the 11th and 13th harmonics.
Inventors
- 👤 John Rosa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 23:24
CPC Classifications
H; H02; H02M; H02M7/00; H02M7/02; H02M7/04; H02M7/12; H02M7/145; H02M7/155; H02M7/1552
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
196 words
A static-controlled converter including a single hexagon transformer comprising: a three-phase AC current winding and six serially connected windings defining the six sides of the hexagon, each side being connected to opposite polarity DC terminals via controlled static switches, twelve pairs of said controlled static switches being symmetrically associated with the six sides of the hexagon, two of said pairs being symmetrically disposed relative to a common side of the hexagon and each pair forming a closed-loop with the opposite polarity terminals while having a common connection with the corresponding one of said windings; and means for sequentially controlling for conduction the switches of even number in said pairs in relation to one terminal and the switches of odd number in said pairs in relation to the other terminal by rotation about opposite sides of the hexagon, the sequence of said switches being synchronous with the frequency of said three-phase current, gating of a switch in a pair lagging gating of the next switch for the adjoining pair in the sequence by a predetermined firing angle, thereby create a 24-pulse output voltage and 24-pulse AC line currents with a minimum in the AC line harmonic contents.
Claim 2
Dependent Claim
196 words
A static-controlled converter including a single hexagon transformer comprising: a three-phase AC current winding and six serially connected windings defining the six sides of the hexagon, each side being connected to opposite polarity DC terminals via controlled static switches, twelve pairs of said controlled static switches being symmetrically associated with the six sides of the hexagon, two of said pairs being symmetrically disposed relative to a common side of the hexagon and each pair forming a closed-loop with the opposite polarity terminals while having a common connection with the corresponding one of said windings; and means for sequentially controlling for conduction the switches of even number in said pairs in relation to one terminal and the switches of odd number in said pairs in relation to the other terminal by rotation about opposite sides of the hexagon, the sequence of said switches being synchronous with the frequency of said three-phase current, gating of a switch in a pair lagging gating of the next switch for the adjoining pair in the sequence by a predetermined firing angle, thereby create a 24-pulse output voltage and 24-pulse AC line currents with a minimum in the AC line harmonic contents.
Claim 3
Dependent Claim
16 words
The hexagon converter of claim 1 with said lagging firing angle amounting to 15 electrical degrees.
Claim 4
Dependent Claim
135 words
The hexagon converter of claim 2 with two groups of three inductors being provided, one inductor group being interposed between said switches and a corresponding one of said DC terminals; two inductors of a group being connected to the respective first switches of a hexagon winding for the associated DC terminal polarity, and the third inductor thereof being connected to with the adjoining first switch of the adjoining hexagon winding in the switch firing sequence; thereby to reduce with two inductors the rate of change of the commutating current in two commutating switches so as to extend the duration of the attending commutation and reduce the harmonics, and said two inductors being effective with the third inductor to prevent interference by the next switch to be fired upon the commutation of said two commutating switches.
Claim 5
Dependent Claim
49 words
The hexagon converter of claim 3 with one of said two groups of three inductors having a different inductance value than the inductance value of the other, such inductance values being selected for creating a balanced commutating overlap, thereby to minimize the harmonic content of the AC line currents.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-11-25 | 1995-05-27 | 1995-11-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-11-25 | 1999-05-27 | 1999-11-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-11-25 | 2003-05-27 | 2003-11-26 | $7700.00 | Window Closed / Lapsed |