US3859587A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thyristor protection circuit for inverters
Assignee: Lorain Products Corp
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Filing: 1974-01-07
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Granted: 1975-01-07
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Expires: 1994-01-07
Abstract
Abstract A circuit for preventing reverse voltage breakdown in the thyristors of center-tapped source inverters. A plurality of clamp diodes are utilized to limit the reverse voltage across inverter thyristors in the presence of the voltage spikes produced by the inductances of the inverter during commutation. The reverse voltage is limited to a value low enough to protect the thyristors from reverse voltage breakdown and yet high enough to assure a relatively short reverse recovery time.
Inventors
- 👤 Harold J Brown
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 12:43
CPC Classifications
H; H02; H02M; H02M7/00; H02M7/42; H02M7/44; H02M7/48; H02M7/505; H02M7/515; H02M7/5157
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
199 words
In an inverter, in combination: a positive bus; a negative bus; an a-c bus; first switching means for controlling the flow of current between the positive bus and the a-c bus; second switching means for controlling the flow of current between the a-c bus and the negative bus; means for alternately energizing the first and second switching means; a commutating inductor having first and second coupled windings; means for connecting the first switching means to the positive bus through the first winding of the commutating inductor and to the a-c bus; means for connecting the second switching means to the negative bus through the second winding of the commutating inductor and to the a-c bus. first and seCond capacitors; means for connecting the first capacitor between the positive bus and the a-c bus; means for connecting the second capacitor between the negative bus and the a-c bus; means for limiting the reverse voltages across the first and second switching means to voltages approximately equal to the voltages across the first and second capacitors; and means for connecting the limiting means to the negative bus, to the first switching means, to the positive bus and to the second switching means.
Claim 2
Dependent Claim
199 words
In an inverter, in combination: a positive bus; a negative bus; an a-c bus; first switching means for controlling the flow of current between the positive bus and the a-c bus; second switching means for controlling the flow of current between the a-c bus and the negative bus; means for alternately energizing the first and second switching means; a commutating inductor having first and second coupled windings; means for connecting the first switching means to the positive bus through the first winding of the commutating inductor and to the a-c bus; means for connecting the second switching means to the negative bus through the second winding of the commutating inductor and to the a-c bus. first and seCond capacitors; means for connecting the first capacitor between the positive bus and the a-c bus; means for connecting the second capacitor between the negative bus and the a-c bus; means for limiting the reverse voltages across the first and second switching means to voltages approximately equal to the voltages across the first and second capacitors; and means for connecting the limiting means to the negative bus, to the first switching means, to the positive bus and to the second switching means.
Claim 3
Dependent Claim
36 words
An inverter as set forth in claim 1 including resonant discharging means for transferring energy between the first and second capacitors and means for connecting the resonant discharging means to the first and second switching means.
Claim 4
Dependent Claim
60 words
An inverter as set forth in claim 1 wherein the limiting means includes a first clamping diode connected between the negative bus and the first switching means to limit the voltage across the first switching means and a second clamping diode connected between the positive bus and the second switching means to limit the voltage across the second switching means.
Claim 5
Dependent Claim
42 words
An inverter as set forth in claim 1 wherein the first and second capacitors are located remotely from the first and second switching means and are connected to the first and second switching means through connectors having a relatively low distributed inductance.
Claim 6
Dependent Claim
211 words
In an inverter in combination: a positive bus; a negative bus; an a-c bus; first switching means for controlling the flow of current between the positive bus and the a-c bus; second switching means for controlling the flow of current between the a-c bus and the negative bus; means for alternately energizing the first and second switching means; a commutating inductor having first and second coupled windings; means for connecting the first switching means to the positive bus through the first winding of commutating inductor and to the a-c bus; means for connecting the second switching means to the negative bus through the second winding of the commutating inductor and to the a-c bus; first and second capacitors; means for connecting the first capacitor between the positive bus and the a-c bus; means for connecting the second capacitor between the negative bus and the a-c bus; first and second voltage clamping means for limiting the reverse voltages across the respective first and second switching means to the voltage between the positive and negative busses; means for connecting the first voltage clamping means to the negative bus and to the first switching means; and means for connecting the second voltage clamping means to the positive bus and to the second switching means.
Claim 7
Dependent Claim
211 words
In an inverter in combination: a positive bus; a negative bus; an a-c bus; first switching means for controlling the flow of current between the positive bus and the a-c bus; second switching means for controlling the flow of current between the a-c bus and the negative bus; means for alternately energizing the first and second switching means; a commutating inductor having first and second coupled windings; means for connecting the first switching means to the positive bus through the first winding of commutating inductor and to the a-c bus; means for connecting the second switching means to the negative bus through the second winding of the commutating inductor and to the a-c bus; first and second capacitors; means for connecting the first capacitor between the positive bus and the a-c bus; means for connecting the second capacitor between the negative bus and the a-c bus; first and second voltage clamping means for limiting the reverse voltages across the respective first and second switching means to the voltage between the positive and negative busses; means for connecting the first voltage clamping means to the negative bus and to the first switching means; and means for connecting the second voltage clamping means to the positive bus and to the second switching means.
Claim 8
Dependent Claim
42 words
An inverter as set forth in claim 5 wherein the first and second capacitors are located remotely from the first and second switching means and are connected to the first and second switching means through connectors having a relatively low distributed inductance.
Claim 9
Dependent Claim
97 words
An inverter as set forth in claim 5 wherein the means for connecting the first clamping means to the negative bus and to the first switching means comprises means for connecting the first clamping means to the negative bus and to the junction of the first winding and the first switching means and wherein the means for connecting the second clamping means to the positive bus and to the second switching means comprises means for connecting the second clamping means to the positive bus and to the junction of the second winding and the second switching means.
Claim 10
Dependent Claim
62 words
An inverter as set forth in claim 7 including a resonant discharge circuit for transferring energy between the first and second capacitors, said discharge circuit comprising an inductor in series with a diode, said discharge circuit being connected between the junction of the first winding and the first switching means and the junction of the second winding and the second switching means.
Claim 11
Dependent Claim
232 words
In an inverter, in combiNation: a positive bus; a negative bus; an a-c bus; a first thyristor for controlling the flow of current between the positive bus and the a-c bus; a second thyristor for controlling the flow of current between the a-c bus and the negative bus; means for alternately energizing the first and second thyristors; a commutating inductor having first and second coupled windings; means for connecting the first thyristor to the positive bus through the first winding of the commutating inductor; means for connecting the second thyristor to the negative bus through the second winding of the commutating inductor; means for connecting the first and second thyristors to the a-c bus; first and second commutating capacitors; means for connecting the first capacitor between the positive bus and the a-c bus; means for connecting the second capacitor between the negative bus and the a-c bus; a first clamping diode for limiting the reverse voltage across the first thyristor to the voltage across the second capacitor; a second clamping diode for limiting the reverse voltage across the second thyristor to the voltage across the first capacitor; means for connecting the first clamping diode between the negative bus and the junction of the first thyristor and the first winding; and means for connecting the second clamping diode between the positive bus and the junction of the second thyristor and the second winding.
Claim 12
Dependent Claim
232 words
In an inverter, in combiNation: a positive bus; a negative bus; an a-c bus; a first thyristor for controlling the flow of current between the positive bus and the a-c bus; a second thyristor for controlling the flow of current between the a-c bus and the negative bus; means for alternately energizing the first and second thyristors; a commutating inductor having first and second coupled windings; means for connecting the first thyristor to the positive bus through the first winding of the commutating inductor; means for connecting the second thyristor to the negative bus through the second winding of the commutating inductor; means for connecting the first and second thyristors to the a-c bus; first and second commutating capacitors; means for connecting the first capacitor between the positive bus and the a-c bus; means for connecting the second capacitor between the negative bus and the a-c bus; a first clamping diode for limiting the reverse voltage across the first thyristor to the voltage across the second capacitor; a second clamping diode for limiting the reverse voltage across the second thyristor to the voltage across the first capacitor; means for connecting the first clamping diode between the negative bus and the junction of the first thyristor and the first winding; and means for connecting the second clamping diode between the positive bus and the junction of the second thyristor and the second winding.
Claim 13
Dependent Claim
30 words
An inverter as set forth in claim 9 including a first reactive power diode connected across the first capacitor and a second reactive power diode connected across the second capacitor.
Claim 14
Dependent Claim
196 words
In an inverter, in combination: a positive bus; a negative bus; an a-c bus; first switching means for controlling the flow of current between the positive bus and the a-c bus; second switching means for controlling the flow of current between the a-c bus and the negative bus; means for alternately energizing the first and second switching means; a commutating inductor having first and second coupled windings; means for connecting the first switching means to the positive bus through the first winding of the commutating inductor; means for connecting the first switching means to the a-c bus; means for connecting the second switching means between the negative bus and the a-c bus through the second winding of the commutating inductor; first and second capacitors; means for connecting the first capacitor between the positive bus and the a-c bus; means for connecting the second capacitor between the negative bus and the a-c bus; a clamping diode for limiting the reverse voltage across the first switching means to the voltage across the second capacitor; and means for connecting the clamping diode to the negative bus and to the junction of the first switching means and the first winding.
Claim 15
Dependent Claim
196 words
In an inverter, in combination: a positive bus; a negative bus; an a-c bus; first switching means for controlling the flow of current between the positive bus and the a-c bus; second switching means for controlling the flow of current between the a-c bus and the negative bus; means for alternately energizing the first and second switching means; a commutating inductor having first and second coupled windings; means for connecting the first switching means to the positive bus through the first winding of the commutating inductor; means for connecting the first switching means to the a-c bus; means for connecting the second switching means between the negative bus and the a-c bus through the second winding of the commutating inductor; first and second capacitors; means for connecting the first capacitor between the positive bus and the a-c bus; means for connecting the second capacitor between the negative bus and the a-c bus; a clamping diode for limiting the reverse voltage across the first switching means to the voltage across the second capacitor; and means for connecting the clamping diode to the negative bus and to the junction of the first switching means and the first winding.
Claim 16
Dependent Claim
195 words
In an inverter, in combination: a positive bus; a negative bus; an a-c bus; first switching means for controlling the flow of current between the positive bus and the a-c bus; second switching means for controlling the flow of current between the a-c bus and the negative bus; means for alternately energizing the first and second swtiching means; a commutating inductor having first and second coupled windings; means for connecting the first switching means between the positive bus and the a-c bus through the first winding of the commutating inductor; means for connecting the second switching means to the negative bus through the second winding of the commutating inductor; means for connecting the second switching means to the a-c bus; first and second capacitors; means for connecting the first capacitor between the positive bus and the a-c bus; means for connecting the second capacitor between the negative bus and the a-c bus; a clamping diode for limiting the reverse voltage acroSs the second switching means to the voltage across the first capacitor; and means for connecting the clamping diode to the positive bus and the junction of the second switching means and the second winding.
Claim 17
Dependent Claim
195 words
In an inverter, in combination: a positive bus; a negative bus; an a-c bus; first switching means for controlling the flow of current between the positive bus and the a-c bus; second switching means for controlling the flow of current between the a-c bus and the negative bus; means for alternately energizing the first and second swtiching means; a commutating inductor having first and second coupled windings; means for connecting the first switching means between the positive bus and the a-c bus through the first winding of the commutating inductor; means for connecting the second switching means to the negative bus through the second winding of the commutating inductor; means for connecting the second switching means to the a-c bus; first and second capacitors; means for connecting the first capacitor between the positive bus and the a-c bus; means for connecting the second capacitor between the negative bus and the a-c bus; a clamping diode for limiting the reverse voltage acroSs the second switching means to the voltage across the first capacitor; and means for connecting the clamping diode to the positive bus and the junction of the second switching means and the second winding.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-01-06 | 1978-07-08 | 1979-01-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-06 | 1982-07-08 | 1983-01-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-06 | 1986-07-08 | 1987-01-07 | $7700.00 | Window Closed / Lapsed |