CA1273057A - Thyristor firing system - Google Patents
Thyristor firing systemInfo
- Publication number
- CA1273057A CA1273057A CA000498343A CA498343A CA1273057A CA 1273057 A CA1273057 A CA 1273057A CA 000498343 A CA000498343 A CA 000498343A CA 498343 A CA498343 A CA 498343A CA 1273057 A CA1273057 A CA 1273057A
- Authority
- CA
- Canada
- Prior art keywords
- thyristor
- gate electrode
- voltage
- power semiconductor
- firing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/10—Modifications for increasing the maximum permissible switched voltage
- H03K17/105—Modifications for increasing the maximum permissible switched voltage in thyristor switches
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/04—Modifications for accelerating switching
- H03K17/0403—Modifications for accelerating switching in thyristor switches
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
- H03K17/78—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used using opto-electronic devices, i.e. light-emitting and photoelectric devices electrically- or optically-coupled
- H03K17/79—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used using opto-electronic devices, i.e. light-emitting and photoelectric devices electrically- or optically-coupled controlling bipolar semiconductor switches with more than two PN-junctions, or more than three electrodes, or more than one electrode connected to the same conductivity region
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- Power Conversion In General (AREA)
Abstract
THYRISTOR FIRING SYSTEM
Abstract of the Disclosure A firing system for simultaneously firing or gating on several thyristors arranged in a series configuration across a high voltage, requires no isolation pulse transformers to provide pulses to fire the thyristors. A transformer having a primary winding connected to an external AC source and a secondary connected to a rectifier which provides power to the firing system, provides isolation. A
power semiconductor switching device is connected between the rectifier and the gate electrode of the respective thyristor. The power semiconductor switching device also has a gate electrode. A fibre optic receiver for each thyristor receives a light pulse which represents the firing signal and provides a signal to circuitry connecting with the gate electrode of the power semiconductor to cause it to conduct and provide a firing pulse to the gate electrode of the respective thyristor.
Abstract of the Disclosure A firing system for simultaneously firing or gating on several thyristors arranged in a series configuration across a high voltage, requires no isolation pulse transformers to provide pulses to fire the thyristors. A transformer having a primary winding connected to an external AC source and a secondary connected to a rectifier which provides power to the firing system, provides isolation. A
power semiconductor switching device is connected between the rectifier and the gate electrode of the respective thyristor. The power semiconductor switching device also has a gate electrode. A fibre optic receiver for each thyristor receives a light pulse which represents the firing signal and provides a signal to circuitry connecting with the gate electrode of the power semiconductor to cause it to conduct and provide a firing pulse to the gate electrode of the respective thyristor.
Description
~L273~7 - 1 - Case 2~gO
T~IYRISTOR FIRI~G SYSTEM
This invention relates to a firing system or gating system for thyristors, and in particular it relates to a system Eor simultaneously gating or firing a plurality of series-connected th~ristors.
In systems for firing thyristors it is desirable to provide gate pulses or firing pulses with a fast rise-time, and with series-connected thyristors it is desirable to apply the gate pulses simultaneously to the gate electrode of each thyristor in the series arrangement. A series arrangement of thyristors is commonly used in a high voltage environment and this requires voltage isolation.
There are several known arrangemeIIts for providing gate pulses simultaneously to series connected thyristors connected across a high voltage source. One arrangement uses a plurality oE
pulse transformers, one for eacll thyristor. The primary win(.lings of each transformer are connected in series across a control current source wtlich may comprise capacitor means charged to a high voltage and connected to the primary w:inclings through a semiconductor switch. The secondary windirlgs are connected to the gate electrodes of tthe respective thyristors. Canadian Patent No. 1,].23,912 - Kindell, issued May 1~, 19~2 is an example of an arranyement using a plurality of pulse transformers.
~; ~
, ,. . ~, ., ~- - ~ : .
' ' ',':.' :,. ~
~.~73~
~ 2 - Case 28~0 An alternative arranyement uses a pulse transformer having one primary winding and a secondary winding for each thyristor in the series-connected thyristors.
When one or more pulse -transformers are used in the manner referred to above, they must provide both high voltaye isolation and a gati}lg pulse with a very fas-t rise-time. The design requirements for high voltage isolation and for a bandwidth that will give a fast rise-time are not compatible and it is difficult to design a pulse transformer that provides the necessary high voltage isolation, including corona management, and a pulse with a fast rise-time. The pulse transformers are usually complex in design, bulky, temperature sensitive and relatively expensive~ In addition the pulse rise-time may vary between pulse transformers which might cause one thyristor to trigger an undesirable time before another.
In another known arrangement, each of the series-connected thyristors is a light-ac-tivated thyristor which is -fired optically ~y a li~ht pulse transmitted over a light pipe or a fibre optic path.
The light pipe provides the necessary isolation.
Large thyristors which are directly light-activated tend to be considerably more expensive -than thyristors which are activated or fired by a gate pulse.
rrhe present invention uses thyristors in a series-connected arrangement where the thyristors are of a -type actuated by the usual gate pulse or firing pulses. The firing pulse is provided by a pulse circuit which is powered by a power supply connected to an AC source by a power transformer. The power transformer provides the necessary isolation and is a low frequency (e.g. 50 or 60 ~z) transformer of a . . .
~73~
- 3 - Case 28~0 relatively low power rating~ Isola-tion may be provided by large air gaps in the transformer which can be tolerated at the low frequencie6 involved.
Consequently the transformers are not expensive.
There is a power supply and pulse circuit for each thyristor to be gated. The pulse circuit is activated by a light pulse transmitted over an optical path. The time between a light pulse having received and a gating pulse being provided to the thyristor is of the order of tens of nanoseconds so that the difference in the timing of the yate pulses to different thyristors in the series-connected thyristors is not ~ignificant. A safety circuit is provided to ensure the firing of a thyristor that does not fire simultaneously with the other thyristors in the chain of series-connected thyristors.
It is a feature of the invention to provide a firing circuit for series-connected thyristors that is relatively inexpensive.
It is another feature to provide a safety circuit for triggering or gating any thyristor that fails to conduct simultaneously with the other series-connected thyris-tors that have been gated by a firing signal.
It is yet another fea-ture of the inventior to provide an improved gating system for simultaneously gating series-connected tllyristors where the gating pulses have very fast rise-times.
In accordance with a form oE the invention there is provided a thyristor ~iring system for simultaneously firing a plurality of thyristors connected in series between a high voltage source and ~ a reference and requiring no isolating pulse ; 35 transformers, each thyristor having an anode, a cathode and a gate electrode, comprising for each , ~ ~7~357 - 4 - Case 2~0 thyristor a power supply including a transformer having a primary windiny for connection to an external AC power source and a secondary winding connected to a rectifier means, and a DC output from said rectifier means, said transformer providing isolation between said external AC power source and said firing system, a power semiconductor switching device having a low resistance conducting condition and a non-conducting condition and being responsive to an input signal at a gate electrode thereof to change from one condition to the other, said power semiconductor being connected between the gate electrode of the respective thyristor and said DC
output, a fibre optic receiver for receiving li~lt pulses for initiating a firing signal, and circuit means connecting said fibre optic receiver and the gate electrode of said power semiconductor and switching device responsive to a firing signal from said fibre optic receiver to provide an input signal to said power semiconductor device gate electrode tv change said power semiconductor switching device to its low resistance condition ancl provide a pulse to said gate electrode of said thyristor to cause said thyristor to fire.
The invention will be described in more cletail witll reference to the drawings, in which E'igure 1 is the single figure of drawings and is a schematic diayram depicting the invention in one form thereof.
Referring to E'igure 1, thyristor 10 represents one thyristor in a plurality of series-connected thyristors where the dashed lines 11 indicate the series connections. A series connection of thyristors is normally used where the thyristors are across a hiyh voltage. Thyris-tors connected in such a series arrangement normally have a snubber .
~3 ~
- 5 - Case 2880 circuit connected across each thyristor to reduce or "snub" the rate of change of sharply rising voltage transients across the thyristor. The snubber circuit is shown as comprising resistors 12 and 14 and capacitor 15.
The firing system of Fiyure 1 includes a power supply 16 having a transformer 17 which has shielding grounded at 1~. The primary winding 20 may be connected to a suitable alternating power source, for example, a 115 volt AC supply of 50 or 60 I-Iz. Xt should be noted that this transformer 17 provides isolation for the ~iring system which is connected with thyristors operating at high voltages.
The secondary winding 21 is connected to a bridge rectifier 22 which provides a DC supply between conductors 23 and 24. A filter capacitor 25 is connected across conductors 23 and 24 to provide filtering, and a resistor 26 and light emitting diode or LED 27 are connected across conductors 23 and 2 to provide an indication of power supply operation.
A regulator 30, such as, for example, a 7805 monolithic regulator, is connected to the supply and provides a regulated DC voltage on conductor 28. A
diode 29, connected between conductors 23 and 2~, protects regulator 30 against back bias.
A fibre optic receiver 31, i.e. a light responsive device 31, which in one commercially available form includes a pre-amplifier which operates a transistor type ~witch. The switch has connections with conductors 32 and 33. A network having a series connec-tion of resistor 3~, zener diode 37, resistor 35 and resistor 36 is connected between conductors 23 and 24. The output from ~ibre optic receiver 31 is connected across resistor 36. A
capacitor 39 provides local power supply filtering for the fibre optic receiver 31. The zener diode 37 3 ~7305i~
- 6 - ~ase 28~0 ls included in the series connection only to cause a voltage drop which ensures that the voltage on conductor 32 does not exceed the withstand voltage level of the fibre optic receiver 31. The fibre optic receiver 31 presents a very high resistance between conductors 32 and 33 when no light is being received, and a low resistance when a pulse of light is received.
Thus, when fibre optic receiver 31 receives a pulse of light, the resistance it presents between conductors 32 and 33 drops and current flows through resistors 34 and 35, zener diode 37 and receiver 31 causing transistor 38 to turn on. When transistor 3 turns on it causes a current to flow through resistors ~3 and 44, raising the voltage at point 40. Point 40 is eonnected to gate electrode 41 of a power semiconductor switching device or power FET
device 42. This inerease in voltage on the gate of power FET ~2 eauses it to conduet and eurrent ~lows through resistors 45 and 46, which have low values of resistanee, for exaMple, of the order of 10 and 20 ohms respectively. Power FET 42 has a high transeonductanee and provides a fast rising pulse on conduetor ~7 which is eonnectecl to gate eleetrode 4~
of thyristor 10 thereby turniny on thyristor 10. The zener diodes 62 are to prevent exeess voltage on ~3ate electrode 41. A protective diode ~9 is connected to the gate eleetrode 4~ of thyristor 10.
A connection to the thyristor series chair is made hy conductor 50 and resistor 51 which provides across rec-tifier bridge 52, a portion to tlle alternating voltage across thyristor 10. The output from bridge 52 is across conductors 53 and 54 and energizes light emitting diode or LED 55 in the fibre 36 optic transmitter 56. An additional diode 59 prevents reverse bias across LED 55. The L~D 55 ff.
':
-.
3L273~57 - 7 - Case 2880 provides a pulsing liyht output (except of course when thyristor 10 is conductiny) to indicate operationO If the thyristor should fail and become a short circuit, there would, of course, be no light pulse output from fibre optic transmitter 56.
Because thyristor 10 is one of a series of thyristors connected across a high voltage, the failure of any one thyristor to turn on when the other thyristors turn on will place a very high voltage across that thyristor and will, in all probability, damage the thyristor. It is therefore desirable to provide a safety circuit which will turn on the thyristor in such a situation, if, of course, the thyristor is -functional~
A voltage is present across resistor 57 due to the connection through resistor 51 and conductor 50 as was previously mentioned. A diode S8 rectifie~
this voltage and charges capacitor 60. A silicon unilateral switch 61, having a thre~hold or breakdown voltage above the voltage normally on capacitor 60, isolates the capacitor 60 from point 40. EIowever, if thyristor 10 should fail to -fire when other thyristors in the same series configuration fire, a considerably higher voltage will be present across resiskor 57 and the charge on capacitor 60 will exceed the threshold voltage of silicon unilateral switch 61, or SUS 61, and it will conduct. As SUS 61 has a negative characteristic, it will ~uickly raise the voltage at point ~0 and power F~T device ~2 will turn on and provide a pulse having a fast rise-time to gate ~8 of thyristor 10 to turn on thyristor 10.
The circuit portion comprising capacitor 60, resistors 51 and 57, and SUS 61 is designed so that it discriminates against false gating of thyristor 10 but provides a gating signal before voltage across thyristor 1~ reaches a destructive level.
: '' .':
.
- 8 - ~ase 2880 It wlll be seen that no pulse transformers are required in the thyristor firing system of t`he invention. The only isolation required is provided by a relatively inexpensive transformer 17, and of course by the fibre optics connected to fibre optic receiver 31 and transmitter 56. A safety system is provided as a bac~-up firing means for each of the thyristors.
While many commercially available components are suitable for use in the circuitry of the invention, and similar circuitry to that 5hown may be designed without departiny from the scope of the invention, the following component values or designations may be of use to those using the inventionO
Resistor 26 2K ohms 36 lOOK
43 lK
57 lK
25Capacitor 60 0.01 ~sd Power FET IRF 530 E'ibre Optic Receiver 31 HE'BR-2501
T~IYRISTOR FIRI~G SYSTEM
This invention relates to a firing system or gating system for thyristors, and in particular it relates to a system Eor simultaneously gating or firing a plurality of series-connected th~ristors.
In systems for firing thyristors it is desirable to provide gate pulses or firing pulses with a fast rise-time, and with series-connected thyristors it is desirable to apply the gate pulses simultaneously to the gate electrode of each thyristor in the series arrangement. A series arrangement of thyristors is commonly used in a high voltage environment and this requires voltage isolation.
There are several known arrangemeIIts for providing gate pulses simultaneously to series connected thyristors connected across a high voltage source. One arrangement uses a plurality oE
pulse transformers, one for eacll thyristor. The primary win(.lings of each transformer are connected in series across a control current source wtlich may comprise capacitor means charged to a high voltage and connected to the primary w:inclings through a semiconductor switch. The secondary windirlgs are connected to the gate electrodes of tthe respective thyristors. Canadian Patent No. 1,].23,912 - Kindell, issued May 1~, 19~2 is an example of an arranyement using a plurality of pulse transformers.
~; ~
, ,. . ~, ., ~- - ~ : .
' ' ',':.' :,. ~
~.~73~
~ 2 - Case 28~0 An alternative arranyement uses a pulse transformer having one primary winding and a secondary winding for each thyristor in the series-connected thyristors.
When one or more pulse -transformers are used in the manner referred to above, they must provide both high voltaye isolation and a gati}lg pulse with a very fas-t rise-time. The design requirements for high voltage isolation and for a bandwidth that will give a fast rise-time are not compatible and it is difficult to design a pulse transformer that provides the necessary high voltage isolation, including corona management, and a pulse with a fast rise-time. The pulse transformers are usually complex in design, bulky, temperature sensitive and relatively expensive~ In addition the pulse rise-time may vary between pulse transformers which might cause one thyristor to trigger an undesirable time before another.
In another known arrangement, each of the series-connected thyristors is a light-ac-tivated thyristor which is -fired optically ~y a li~ht pulse transmitted over a light pipe or a fibre optic path.
The light pipe provides the necessary isolation.
Large thyristors which are directly light-activated tend to be considerably more expensive -than thyristors which are activated or fired by a gate pulse.
rrhe present invention uses thyristors in a series-connected arrangement where the thyristors are of a -type actuated by the usual gate pulse or firing pulses. The firing pulse is provided by a pulse circuit which is powered by a power supply connected to an AC source by a power transformer. The power transformer provides the necessary isolation and is a low frequency (e.g. 50 or 60 ~z) transformer of a . . .
~73~
- 3 - Case 28~0 relatively low power rating~ Isola-tion may be provided by large air gaps in the transformer which can be tolerated at the low frequencie6 involved.
Consequently the transformers are not expensive.
There is a power supply and pulse circuit for each thyristor to be gated. The pulse circuit is activated by a light pulse transmitted over an optical path. The time between a light pulse having received and a gating pulse being provided to the thyristor is of the order of tens of nanoseconds so that the difference in the timing of the yate pulses to different thyristors in the series-connected thyristors is not ~ignificant. A safety circuit is provided to ensure the firing of a thyristor that does not fire simultaneously with the other thyristors in the chain of series-connected thyristors.
It is a feature of the invention to provide a firing circuit for series-connected thyristors that is relatively inexpensive.
It is another feature to provide a safety circuit for triggering or gating any thyristor that fails to conduct simultaneously with the other series-connected thyris-tors that have been gated by a firing signal.
It is yet another fea-ture of the inventior to provide an improved gating system for simultaneously gating series-connected tllyristors where the gating pulses have very fast rise-times.
In accordance with a form oE the invention there is provided a thyristor ~iring system for simultaneously firing a plurality of thyristors connected in series between a high voltage source and ~ a reference and requiring no isolating pulse ; 35 transformers, each thyristor having an anode, a cathode and a gate electrode, comprising for each , ~ ~7~357 - 4 - Case 2~0 thyristor a power supply including a transformer having a primary windiny for connection to an external AC power source and a secondary winding connected to a rectifier means, and a DC output from said rectifier means, said transformer providing isolation between said external AC power source and said firing system, a power semiconductor switching device having a low resistance conducting condition and a non-conducting condition and being responsive to an input signal at a gate electrode thereof to change from one condition to the other, said power semiconductor being connected between the gate electrode of the respective thyristor and said DC
output, a fibre optic receiver for receiving li~lt pulses for initiating a firing signal, and circuit means connecting said fibre optic receiver and the gate electrode of said power semiconductor and switching device responsive to a firing signal from said fibre optic receiver to provide an input signal to said power semiconductor device gate electrode tv change said power semiconductor switching device to its low resistance condition ancl provide a pulse to said gate electrode of said thyristor to cause said thyristor to fire.
The invention will be described in more cletail witll reference to the drawings, in which E'igure 1 is the single figure of drawings and is a schematic diayram depicting the invention in one form thereof.
Referring to E'igure 1, thyristor 10 represents one thyristor in a plurality of series-connected thyristors where the dashed lines 11 indicate the series connections. A series connection of thyristors is normally used where the thyristors are across a hiyh voltage. Thyris-tors connected in such a series arrangement normally have a snubber .
~3 ~
- 5 - Case 2880 circuit connected across each thyristor to reduce or "snub" the rate of change of sharply rising voltage transients across the thyristor. The snubber circuit is shown as comprising resistors 12 and 14 and capacitor 15.
The firing system of Fiyure 1 includes a power supply 16 having a transformer 17 which has shielding grounded at 1~. The primary winding 20 may be connected to a suitable alternating power source, for example, a 115 volt AC supply of 50 or 60 I-Iz. Xt should be noted that this transformer 17 provides isolation for the ~iring system which is connected with thyristors operating at high voltages.
The secondary winding 21 is connected to a bridge rectifier 22 which provides a DC supply between conductors 23 and 24. A filter capacitor 25 is connected across conductors 23 and 24 to provide filtering, and a resistor 26 and light emitting diode or LED 27 are connected across conductors 23 and 2 to provide an indication of power supply operation.
A regulator 30, such as, for example, a 7805 monolithic regulator, is connected to the supply and provides a regulated DC voltage on conductor 28. A
diode 29, connected between conductors 23 and 2~, protects regulator 30 against back bias.
A fibre optic receiver 31, i.e. a light responsive device 31, which in one commercially available form includes a pre-amplifier which operates a transistor type ~witch. The switch has connections with conductors 32 and 33. A network having a series connec-tion of resistor 3~, zener diode 37, resistor 35 and resistor 36 is connected between conductors 23 and 24. The output from ~ibre optic receiver 31 is connected across resistor 36. A
capacitor 39 provides local power supply filtering for the fibre optic receiver 31. The zener diode 37 3 ~7305i~
- 6 - ~ase 28~0 ls included in the series connection only to cause a voltage drop which ensures that the voltage on conductor 32 does not exceed the withstand voltage level of the fibre optic receiver 31. The fibre optic receiver 31 presents a very high resistance between conductors 32 and 33 when no light is being received, and a low resistance when a pulse of light is received.
Thus, when fibre optic receiver 31 receives a pulse of light, the resistance it presents between conductors 32 and 33 drops and current flows through resistors 34 and 35, zener diode 37 and receiver 31 causing transistor 38 to turn on. When transistor 3 turns on it causes a current to flow through resistors ~3 and 44, raising the voltage at point 40. Point 40 is eonnected to gate electrode 41 of a power semiconductor switching device or power FET
device 42. This inerease in voltage on the gate of power FET ~2 eauses it to conduet and eurrent ~lows through resistors 45 and 46, which have low values of resistanee, for exaMple, of the order of 10 and 20 ohms respectively. Power FET 42 has a high transeonductanee and provides a fast rising pulse on conduetor ~7 which is eonnectecl to gate eleetrode 4~
of thyristor 10 thereby turniny on thyristor 10. The zener diodes 62 are to prevent exeess voltage on ~3ate electrode 41. A protective diode ~9 is connected to the gate eleetrode 4~ of thyristor 10.
A connection to the thyristor series chair is made hy conductor 50 and resistor 51 which provides across rec-tifier bridge 52, a portion to tlle alternating voltage across thyristor 10. The output from bridge 52 is across conductors 53 and 54 and energizes light emitting diode or LED 55 in the fibre 36 optic transmitter 56. An additional diode 59 prevents reverse bias across LED 55. The L~D 55 ff.
':
-.
3L273~57 - 7 - Case 2880 provides a pulsing liyht output (except of course when thyristor 10 is conductiny) to indicate operationO If the thyristor should fail and become a short circuit, there would, of course, be no light pulse output from fibre optic transmitter 56.
Because thyristor 10 is one of a series of thyristors connected across a high voltage, the failure of any one thyristor to turn on when the other thyristors turn on will place a very high voltage across that thyristor and will, in all probability, damage the thyristor. It is therefore desirable to provide a safety circuit which will turn on the thyristor in such a situation, if, of course, the thyristor is -functional~
A voltage is present across resistor 57 due to the connection through resistor 51 and conductor 50 as was previously mentioned. A diode S8 rectifie~
this voltage and charges capacitor 60. A silicon unilateral switch 61, having a thre~hold or breakdown voltage above the voltage normally on capacitor 60, isolates the capacitor 60 from point 40. EIowever, if thyristor 10 should fail to -fire when other thyristors in the same series configuration fire, a considerably higher voltage will be present across resiskor 57 and the charge on capacitor 60 will exceed the threshold voltage of silicon unilateral switch 61, or SUS 61, and it will conduct. As SUS 61 has a negative characteristic, it will ~uickly raise the voltage at point ~0 and power F~T device ~2 will turn on and provide a pulse having a fast rise-time to gate ~8 of thyristor 10 to turn on thyristor 10.
The circuit portion comprising capacitor 60, resistors 51 and 57, and SUS 61 is designed so that it discriminates against false gating of thyristor 10 but provides a gating signal before voltage across thyristor 1~ reaches a destructive level.
: '' .':
.
- 8 - ~ase 2880 It wlll be seen that no pulse transformers are required in the thyristor firing system of t`he invention. The only isolation required is provided by a relatively inexpensive transformer 17, and of course by the fibre optics connected to fibre optic receiver 31 and transmitter 56. A safety system is provided as a bac~-up firing means for each of the thyristors.
While many commercially available components are suitable for use in the circuitry of the invention, and similar circuitry to that 5hown may be designed without departiny from the scope of the invention, the following component values or designations may be of use to those using the inventionO
Resistor 26 2K ohms 36 lOOK
43 lK
57 lK
25Capacitor 60 0.01 ~sd Power FET IRF 530 E'ibre Optic Receiver 31 HE'BR-2501
Claims (6)
1. A thyristor firing system for simultaneously firing a plurality of thyristors connected in series between a high voltage source and a reference and requiring no isolating pulse transformers, each thyristor having an anode, a cathode and a gate electrode, comprising for each thyristor a power supply including a transformer having a primary winding for connection to an external AC power source and a secondary winding connected to a rectifier means, and a DC output from said rectifier means, said transformer providing isolation between said external AC power source and said firing system, a power semiconductor switching device having a low resistance conducting condition and a non-conducting condition and being responsive to an input signal at a gate electrode thereof to change from one condition to the other, said power semiconductor being connected between the gate electrode of the respective thyristor and said DC
output, a fibre optic receiver for receiving light pulses for initiating a firing signal, and circuit means connecting said fibre optic receiver and the gate electrode of said power semiconductor switching device and responsive to a firing signal from said fibre optic receiver to provide an input signal to said power semiconductor device gate electrode to change said power semiconductor switching device to its low resistance condition and provide a pulse to said gate electrode of said thyristor to cause said thyristor to fire.
- 10 - Case 2880
output, a fibre optic receiver for receiving light pulses for initiating a firing signal, and circuit means connecting said fibre optic receiver and the gate electrode of said power semiconductor switching device and responsive to a firing signal from said fibre optic receiver to provide an input signal to said power semiconductor device gate electrode to change said power semiconductor switching device to its low resistance condition and provide a pulse to said gate electrode of said thyristor to cause said thyristor to fire.
- 10 - Case 2880
2. A thyristor firing system according to claim 1 in which said circuit means includes a transistor switch in a normally non-conducting state and having an output connected between said DC output and an input to said gate electrode of said power semiconductor switching device, said transistor switch being responsive to said firing signal from said fibre optic receiver to charge to a conducting state to cause the voltage to suddenly increase at said gate electrode of power semiconductor switching device thereby causing said power semiconductor to change to its low resistance conducting condition.
3. A thyristor firing system according to claim 1 or 2 and further comprising a capacitor, a rectifier means for charging said capacitor, a silicon unilateral switch having a predetermined threshold voltage higher than the voltage of the normal charge on said capacitor, connected between said capacitor and said gate electrode of power semiconductor switching device, and circuit means connected to the respective thyristor and responsive to an increase in voltage across said thyristor due to a failure of the respective thyristor to fire simultaneously with other thyristor in the series connected thyristors, to increase the voltage of the charge on said capacitor above the threshold of said silicon unilateral switch to cause it to conduct and raise the voltage at said gate electrode of said power semiconductor switching device to change it to its low resistance condition.
4. A thyristor firing system for simultaneously firing a plurality of thyristors connected in series between a high voltage source and - 11 - Case 2880 Claim 4 continued:
a reference and requiring no isolating pulse transformers, each thyristor having an anode, a cathode and a gate electrode, comprising a power supply for each thyristor in the series connected thyristors, having a transformer, rectifier means and a DC output, said transformer having a primary winding for connection to an external AC power source and a secondary winding connected to said rectifier means, said rectifier means being connected to said DC output for providing rectified power thereto, said transformer providing isolation between the high voltage of the respective thyristor in the series connection of thyristors and said AC power source, a power semiconductor switching device for each thyristor in said series connected thyristors having first and second power electrodes and a gate electrode, said power semiconductor switching device having a low resistance conducting condition between said first and second electrodes and a high resistance non-conducting condition, and being responsive to the voltage on said gate electrode thereof for switching between said conducting and non-conducting condition, said first electrode being connected to the respective said DC output and the second electrode being connected to the gate electrode of the respective thyristor, a fibre optic receiver for each said thyristor in said series connected thyristors for receiving light pulses for simultaneously initiating the firing of each respective thyristor, and responsive to a light pulse for providing a firing signal, and circuit means for each said thyristor in said series-connected thyristors, responsive to a - 12 - Case 2880 firing signal from the respective fibre optic receiver to change the voltage on the gate electrode of said power semiconductor switching device to cause it to change to its conducting condition and provide a firing pulse to the gate electrode of the respective thyristor.
5. A thyristor firing system according to
4. A thyristor firing system for simultaneously firing a plurality of thyristors connected in series between a high voltage source and - 11 - Case 2880 Claim 4 continued:
a reference and requiring no isolating pulse transformers, each thyristor having an anode, a cathode and a gate electrode, comprising a power supply for each thyristor in the series connected thyristors, having a transformer, rectifier means and a DC output, said transformer having a primary winding for connection to an external AC power source and a secondary winding connected to said rectifier means, said rectifier means being connected to said DC output for providing rectified power thereto, said transformer providing isolation between the high voltage of the respective thyristor in the series connection of thyristors and said AC power source, a power semiconductor switching device for each thyristor in said series connected thyristors having first and second power electrodes and a gate electrode, said power semiconductor switching device having a low resistance conducting condition between said first and second electrodes and a high resistance non-conducting condition, and being responsive to the voltage on said gate electrode thereof for switching between said conducting and non-conducting condition, said first electrode being connected to the respective said DC output and the second electrode being connected to the gate electrode of the respective thyristor, a fibre optic receiver for each said thyristor in said series connected thyristors for receiving light pulses for simultaneously initiating the firing of each respective thyristor, and responsive to a light pulse for providing a firing signal, and circuit means for each said thyristor in said series-connected thyristors, responsive to a - 12 - Case 2880 firing signal from the respective fibre optic receiver to change the voltage on the gate electrode of said power semiconductor switching device to cause it to change to its conducting condition and provide a firing pulse to the gate electrode of the respective thyristor.
5. A thyristor firing system according to
claim 4 and further comprising, a circuit for each thyristor in said series connected thyristors, connected across the respective thyristor and including a rectifier and a capacitor and responsive to the voltage across the thyristor to charge the capacitor to a predetermined level, a silicon unilateral switch connected between said capacitor and the gate electrode of said power semiconductor switching device, and having a threshold greater than said predetermined level thereby remaining non-conducting, an increase in voltage across the respective thyristor due to failure of that thyristor to fire simultaneously with other thyristors in the series connected thyristors causing an increase of the charge on said capacitor above said threshold value and causing the respective silicon unilateral switch to conduct and change the voltage on the gate electrode of said power semiconductor switching device to cause it to conduct.
6. A thyristor firing system according to
6. A thyristor firing system according to
claim 5 and further comprising rectifier means connected to said circuit for each thyristor connected across the respective thyristor, for providing a voltage pulse for each alternating voltage occurrence across said respective thyristor, and a fibre optic transmitter responsive to the voltage pulses for providing a light pulse - 13 - Case 2880
Claim 6 continued:
representing the occurrence of a voltage across the respective thyristor.
Raymond A. Eckersley 1420 Dupont Street Toronto, Ontario Patent Agent of the Applicant
representing the occurrence of a voltage across the respective thyristor.
Raymond A. Eckersley 1420 Dupont Street Toronto, Ontario Patent Agent of the Applicant
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000498343A CA1273057A (en) | 1985-12-20 | 1985-12-20 | Thyristor firing system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000498343A CA1273057A (en) | 1985-12-20 | 1985-12-20 | Thyristor firing system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1273057A true CA1273057A (en) | 1990-08-21 |
Family
ID=4132142
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000498343A Expired - Fee Related CA1273057A (en) | 1985-12-20 | 1985-12-20 | Thyristor firing system |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1273057A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112953469A (en) * | 2021-01-29 | 2021-06-11 | 华中科技大学 | Hydrogen thyratron high-pressure suspension trigger and control system thereof |
-
1985
- 1985-12-20 CA CA000498343A patent/CA1273057A/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112953469A (en) * | 2021-01-29 | 2021-06-11 | 华中科技大学 | Hydrogen thyratron high-pressure suspension trigger and control system thereof |
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