CN111786354B - Thyristor short-circuit protection circuit and device - Google Patents
Thyristor short-circuit protection circuit and device Download PDFInfo
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- CN111786354B CN111786354B CN202010702370.5A CN202010702370A CN111786354B CN 111786354 B CN111786354 B CN 111786354B CN 202010702370 A CN202010702370 A CN 202010702370A CN 111786354 B CN111786354 B CN 111786354B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/22—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for distribution gear, e.g. bus-bar systems; for switching devices
- H02H7/222—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for distribution gear, e.g. bus-bar systems; for switching devices for switches
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/08—Modifications for protecting switching circuit against overcurrent or overvoltage
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Abstract
The invention provides a thyristor short-circuit protection circuit and a device, wherein the circuit comprises: the overcurrent detection module, the time base integrated module, triode Q1, triode Q2, resistance R1 and optoelectronic coupler, when the thyristor takes place short circuit fault, the overcurrent detection module outputs first control signal so that triode Q1 is in the off-state, the trigger end of the time base integrated module receives high level signal, make the state of time base integrated module overturn, the output of time base integrated module exports 0V, namely the first input of optoelectronic coupler receives 0V voltage, the first output and the second output of optoelectronic coupler are in the off-state, and then lead to triode Q2 to be in the off-state, the emitter output voltage of triode Q2 is 0V, so that the thyristor loses the electricity, namely after the thyristor takes place short circuit fault, the power supply of thyristor drive circuit can automatic disconnection by this circuit, thereby play the protective thyristor effect.
Description
Technical Field
The present invention relates to the field of electronic circuit technology, and in particular, to a thyristor short-circuit protection circuit and device.
Background
The thyristor is a power semiconductor switching element and has the characteristics of high economy, simple control and the like. Therefore, the application of the thyristor in the industry is more and more extensive, and along with the increase of the application range of the industry, the effect of the thyristor is more and more comprehensive, such as an intermediate frequency power supply, a controllable rectification power supply, various converters, a frequency converter and the like, and most high-power rectification systems utilize the thyristor to realize rectification and current regulation.
Generally, a thyristor is directly connected with a transformer winding, if the thyristor has a short-circuit fault, the transformer will be caused with an interphase short circuit, which causes a large direct economic loss; meanwhile, the transformer needs to be replaced after the transformer fails, and the process has a long construction period, so that certain indirect loss is caused.
Therefore, a short-circuit protection circuit for a thyristor is needed.
Disclosure of Invention
Accordingly, it is desirable to provide a thyristor short-circuit protection circuit and device in response to the problems of the prior art.
A thyristor short protection circuit, the circuit comprising: the device comprises an overcurrent detection module, a time base integration module, a triode Q1, a triode Q2, a resistor R1 and a photoelectric coupler; the input end of the over-current detection module is used for being connected with a phase line over-current detection point, the output end of the over-current detection module is connected with the base electrode of the triode Q1, the emitting electrode of the triode Q1 is used for being grounded, the collecting electrode of the triode Q1 is connected with the triggering end of the time-base integrated module, the triggering end of the time-base integrated module is also used for being connected with a first power supply, the discharging end of the time-base integrated module is connected with the base electrode of the triode Q1, the output end of the time-base integrated module is connected with the first input end of the photoelectric coupler, the second input end of the photoelectric coupler is used for being grounded, the first output end of the photoelectric coupler is used for being connected with a second power supply, the first output end of the photoelectric coupler is also connected with the collecting electrode of the triode Q2, and the second output end of the photoelectric coupler is connected with the base electrode, the emitter of the triode Q2 is used for being connected with the driving end of the thyristor; the overcurrent detection module is used for outputting a first control signal when detecting that an interphase short circuit occurs, so that the triode Q1 is in a cut-off state.
In one embodiment, the overcurrent detection module includes a diode D1, a diode D2, a diode D3, a resistor R2, a resistor R3, and a voltage comparator, a positive-phase input terminal of the voltage comparator is configured to be connected to a third power supply, a positive-phase input terminal of the voltage comparator is respectively connected to an anode of the diode D1, an anode of the diode D2, and an anode of the diode D3, a cathode of the diode D1 is configured to be connected to an a-phase line overcurrent detection point, a cathode of the diode D2 is configured to be connected to a B-phase line overcurrent detection point, a cathode of the diode D3 is configured to be connected to a C-phase line overcurrent detection point, an inverted-phase input terminal of the voltage comparator is configured to be connected to a fourth power supply, an output terminal of the voltage comparator is connected to a base of the triode Q1 through the resistor R2, a base of the triode Q1 is further grounded through, wherein a voltage value of the third power supply is greater than a voltage value of the fourth power supply.
In one embodiment, the over-current detection module further includes a resistor R4 and a resistor R5, the positive-phase input terminal of the voltage comparator is configured to be connected to the third power supply through the resistor R4, the positive-phase input terminal of the over-current detection module is further connected to the first terminal of the resistor R5, and the second terminal of the resistor R5 is respectively connected to the anode of the diode D1, the anode of the diode D2, and the anode of the diode D3.
In one embodiment, the over-current detection module further includes a capacitor C1 and a capacitor C2, the first end of the resistor R5 is further configured to be grounded through the capacitor C1, and the inverting input terminal of the voltage comparator is further configured to be grounded through the capacitor C2.
In one embodiment, the thyristor short-circuit protection circuit further includes a capacitor C3 and a processing module, the reset terminal of the time base integration module is configured to be connected to the first power supply, the reset terminal of the time base integration module is further configured to be grounded through the capacitor C3, and the reset terminal of the time base integration module is further connected to the control terminal of the processing module.
In one embodiment, the thyristor short-circuit protection circuit further includes a resistor R6 and a resistor R7, the output terminal of the time base integration module is connected to the first input terminal of the optoelectronic coupler through the resistor R6, the output terminal of the time base integration module is further connected to the first terminal of the resistor R7, and the second terminal of the resistor R7 is used for grounding.
In one embodiment, the thyristor short-circuit protection circuit further includes a resistor R8, the second terminal of the resistor R7 is configured to be grounded through the resistor R8, and the detection terminal of the processing module is connected to the second terminal of the resistor R7.
In one embodiment, the thyristor short-circuit protection circuit further comprises a voltage regulator tube DW1 and a capacitor C4, the base of the triode Q2 is further used for being grounded through the capacitor C4, the anode of the voltage regulator tube DW1 is used for being grounded, and the cathode of the voltage regulator tube DW1 is connected with the base of the triode Q2.
In one embodiment, the thyristor short-circuit protection circuit further includes a resistor R9 and a light emitting diode LED1, an emitter of the transistor Q2 is connected to an anode of the light emitting diode LED1 through the resistor R9, and a cathode of the light emitting diode LED1 is used for grounding.
In one embodiment, a thyristor short-circuit protection device comprises a thyristor short-circuit protection circuit as described in any of the above embodiments.
When the thyristor has short-circuit fault, the overcurrent detection module outputs a first control signal to enable the triode Q1 to be in a cut-off state, the trigger end of the time-base integrated module receives a high-level signal to enable the state of the time-base integrated module to be overturned, the output end of the time-base integrated module outputs 0V, namely the first input end of the photoelectric coupler receives 0V voltage, the first output end and the second output end of the photoelectric coupler are in a cut-off state, further the triode Q2 is in a cut-off state, the output voltage of the emitter of the triode Q2 is 0V, so that the thyristor is de-energized, namely after the thyristor has short-circuit fault, the circuit can automatically cut off the power supply of the thyristor driving circuit, thereby protecting the thyristor, and in addition, the input and output electric signals of the photoelectric coupler have good isolation effect, the control end and the controlled end of the circuit are isolated from each other, so that the control end of the circuit is better protected from being damaged by strong current interference.
Drawings
FIG. 1 is a schematic circuit diagram of a thyristor short circuit protection circuit in one embodiment of the invention;
fig. 2 is a schematic circuit diagram of a thyristor short-circuit protection circuit in another embodiment of the invention.
Detailed Description
To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
It will be understood that when an element is referred to as being "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not represent the only embodiments.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
For example, there is provided a thyristor short protection circuit comprising: the device comprises an overcurrent detection module, a time base integration module, a triode Q1, a triode Q2, a resistor R1 and a photoelectric coupler; the input end of the over-current detection module is used for being connected with a phase line over-current detection point, the output end of the over-current detection module is connected with the base electrode of the triode Q1, the emitting electrode of the triode Q1 is used for being grounded, the collecting electrode of the triode Q1 is connected with the triggering end of the time-base integrated module, the triggering end of the time-base integrated module is also used for being connected with a first power supply, the discharging end of the time-base integrated module is connected with the base electrode of the triode Q1, the output end of the time-base integrated module is connected with the first input end of the photoelectric coupler, the second input end of the photoelectric coupler is used for being grounded, the first output end of the photoelectric coupler is used for being connected with a second power supply, the first output end of the photoelectric coupler is also connected with the collecting electrode of the triode Q2, and the second output end of the photoelectric coupler is connected with the base electrode, the emitter of the triode Q2 is used for being connected with the driving end of the thyristor; the overcurrent detection module is used for outputting a first control signal when detecting that an interphase short circuit occurs, so that the triode Q1 is in a cut-off state.
In the thyristor short-circuit protection circuit, when the thyristor has a short-circuit fault, the overcurrent detection module outputs a first control signal to enable the triode Q1 to be in a cut-off state, the trigger end of the time-base integrated module receives a high-level signal to enable the state of the time-base integrated module to be reversed, the output end of the time-base integrated module outputs 0V, namely the first input end of the photoelectric coupler receives 0V voltage, the first output end and the second output end of the photoelectric coupler are in a cut-off state, further the triode Q2 is in a cut-off state, the output voltage of the emitter of the triode Q2 is 0V, so that the thyristor is de-energized, namely after the thyristor has a short-circuit fault, the circuit can automatically cut off the power supply of the driving circuit, thereby protecting the thyristor, in addition, the input and output electric signals of the photoelectric coupler have good isolation, so that the control end and the controlled end of, so as to better protect the control terminal of the circuit from being damaged by strong electric interference.
Referring to fig. 1, in one embodiment, a thyristor short-circuit protection circuit 10 includes: the overcurrent detection module 100, the time base integration module U2, the triode Q1, the triode Q2, the resistor R1 and the photoelectric coupler U1; the input end of the over-current detection module 100 is configured to be connected to the phase over-current detection point 200, the output end of the over-current detection module 100 is connected to the base of the transistor Q1, the emitter of the transistor Q1 is configured to be grounded, the collector of the transistor Q1 is connected to the trigger end of the time-based integration module U2, the trigger end of the time-based integration module U2 is further configured to be connected to a first power supply, the discharge end of the time-based integration module U2 is connected to the base of the transistor Q1, the output end of the time-based integration module U2 is connected to the first input end of the photocoupler U1, the second input end of the photocoupler U1 is configured to be grounded, the first output end of the photocoupler U1 is configured to be connected to a second power supply, the first output end of the photocoupler U1 is further connected to the collector of the transistor Q2, the second output end of the photocoupler U1 is connected to the base of the transistor Q2 through the, the emitter of the triode Q2 is used for being connected with the driving end 300 of the thyristor; the overcurrent detection module is used for outputting a first control signal when detecting that an interphase short circuit occurs, so that the triode Q1 is in a cut-off state.
Specifically, the input end of the over-current detection module is used for connecting a phase line over-current detection point, that is, the over-current detection module is used for connecting a thyristor short-circuit fault detection point, when the thyristor has a short-circuit fault, the over-current detection module detects an over-current signal and outputs a first control signal, so that the triode Q1 is in a cut-off state, that is, the emitter and the collector of the triode Q1 are disconnected. In one embodiment, the first control signal is a low level signal. In one embodiment, the over-current detection module outputs the second control signal to turn on the transistor Q1 when the thyristor is operating normally. In one embodiment, the second control signal is a high level signal. It should be understood that when the thyristor has a short-circuit fault, the three-phase line may have an interphase short circuit, and therefore, connecting the input end of the overcurrent detection module to the phase line overcurrent detection point may detect whether the thyristor has a short-circuit fault.
Specifically, the time base integrated module is a real-time base integrated circuit, the trigger end of the time base integrated module is a second pin of the time base integrated module, the output end of the time base integrated module is a third pin of the time base integrated module, and the discharge end of the time base integrated module is a seventh pin of the time base integrated module. When the thyristor normally works, the overcurrent detection module outputs a second control signal to enable the triode Q1 to be in a saturated conduction state, the trigger end of the time-base integration module is pulled down to be at a low level all the time, the output end of the time-base integration module outputs a high-level signal to enable the first output end and the second output end of the photoelectric coupler U1 to be conducted, and the triode Q2 is in a conduction state to output a driving voltage to drive the thyristor to work. When the thyristor has short-circuit fault, the overcurrent detection module outputs a first control signal to cut off the triode Q1, the trigger end of the time-base integrated module receives a high-level signal, the state of the time-base integrated module can be overturned, the discharge end of the time-base integrated module recovers to be short-circuited to the ground and locked, the output end of the time-base integrated module outputs 0V voltage, the first output end and the second output end of the photoelectric coupler U1 are in cut-off states at the moment, the corresponding triode Q2 is also in cut-off states, the driving power supply is immediately turned off to power off the driving circuit of the thyristor, and therefore the thyristor is powered off, and the protection effect is achieved. In one embodiment, the time base integrated module comprises a time base integrated chip and surrounding circuitry. In one embodiment, the model number of the time base integrated chip is NE 555.
Specifically, the thyristor is usually driven by a driving circuit, and the emitter of the transistor Q2 is used for being connected to the driving terminal 300 of the thyristor, which means that the emitter of the transistor Q2 is used for being connected to the power supply terminal of the driving circuit. When the emitter of the triode Q2 outputs 0V voltage, the driving circuit of the thyristor is in a power-off state, and the thyristor cannot be driven to operate, so that the thyristor is correspondingly controlled to be in the power-off state.
Specifically, the over-current detection module in this embodiment and the transistor Q1 form a short-circuit signal comparison and trigger circuit; the time base integrated module forms a bistable circuit; the photoelectric coupler U1 forms a bistable output circuit; the triode Q2 forms a voltage-stabilizing driving power output and controllable circuit. In one embodiment, the voltage output by the transistor Q2 is 10.5V.
Specifically, the online soft starter can achieve a good protection effect by adopting the thyristor short-circuit protection circuit provided in the embodiment.
In the thyristor short-circuit protection circuit, when the thyristor has a short-circuit fault, the overcurrent detection module outputs a first control signal to enable the triode Q1 to be in a cut-off state, the trigger end of the time-base integrated module receives a high-level signal to enable the state of the time-base integrated module to be turned over, the output end of the time-base integrated module outputs 0V, namely the first input end of the photoelectric coupler U1 receives 0V voltage, the first output end and the second output end of the photoelectric coupler U1 are in a cut-off state, further the triode Q2 is in a cut-off state, the output voltage of the emitter of the triode Q2 is 0V, so that the thyristor is de-energized, namely after the thyristor has a short-circuit fault, the circuit can automatically cut off the power supply of a thyristor drive circuit, thereby protecting the thyristor, and in addition, the input and output electric signals of the photoelectric coupler U36, make the control end of this circuit and controlled the end mutual isolation to the control end of this circuit of protection better does not receive the strong current interference to damage, and this circuit has stronger interference killing feature promptly, and can be fine control higher voltage and great electric current open and shut off. .
In order to better realize that the overcurrent detection module outputs a first control signal when detecting that a short-circuit fault occurs between phases, so as to enable the transistor Q1 to be in a cut-off state, referring to fig. 1, in one embodiment, the overcurrent detection module 100 includes a diode D1, a diode D2, a diode D3, a resistor R2, a resistor R3, and a voltage comparator U3, a positive-phase input terminal of the voltage comparator U3 is configured to be connected to a third power supply, a positive-phase input terminal of the voltage comparator U3 is respectively connected to an anode of the diode D1, an anode of the diode D2, and an anode of the diode D3, a cathode of the diode D1 is configured to be connected to the a-phase line overcurrent detection point 210, a cathode of the diode D2 is configured to be connected to the B-phase line overcurrent detection point 220, a cathode of the diode D3 is configured to be connected to the C-phase line overcurrent detection point 230, and an inverted-phase input, the output end of the voltage comparator U3 is connected with the base electrode of the triode Q1 through the resistor R2, the base electrode of the triode Q1 is also connected with the ground through the resistor R3, and the voltage value of the third power supply is larger than that of the fourth power supply. In the overcurrent detection module, when the thyristor has a short-circuit fault, i.e. when the three-phase circuit has an interphase short-circuit fault, the voltage at the positive phase input terminal of the voltage comparator U3 is pulled down to be lower than the voltage of the fourth power supply, so that the voltage comparator U3 outputs the first control signal, i.e. outputs the low level signal, so that the transistor Q1 is in the off state, and when the thyristor normally operates, because the three-phase power is in the normal operating state, the voltage at the positive phase input terminal of the voltage comparator U3 is not pulled down, because the voltage of the third power supply is greater than the voltage of the fourth power supply, the voltage at the positive phase input terminal of the voltage comparator U3 is greater than the voltage at the negative phase input terminal, and the output terminal of the voltage comparator U3 outputs the high level signal, so that the transistor Q1 is in the on state, because the cathodes of the diode D1, the diode D2 and the, the reverse cut-off function is realized, so that when the three-phase line supplies power normally, the high voltage of the three-phase line is not transmitted to the non-inverting input end of the voltage comparator U3, so as to prevent the high voltage from damaging the voltage comparator U3. And diode D1, diode D2 and diode D3 are the combination of A looks line, B looks line and C looks line and become one way, under the condition that sets up a voltage comparator U3, realize the interphase short circuit that appears to the three-phase line and detect to the circuit design cost has been reduced. In one embodiment, the voltage comparator U3 has a model number TL 084. In one embodiment, the diode D1, the diode D2, and the diode D3 are 1N4148 model.
In one embodiment, the over-current detection module further includes a resistor R4 and a resistor R5, a positive-phase input terminal of the voltage comparator U3 is configured to be connected to the third power supply through the resistor R4, the positive-phase input terminal of the over-current detection module is further connected to a first terminal of the resistor R5, and a second terminal of the resistor R5 is connected to an anode of the diode D1, an anode of the diode D2, and an anode of the diode D3, respectively. Specifically, the resistor R4 is a pull-up resistor, and the pull-up is to clamp an indeterminate signal at a high level through a resistor, and the resistor also plays a role in current limiting. Therefore, the voltage comparator U3 is better protected by providing a pull-up resistor at the non-inverting input of the voltage comparator U3 to limit current.
Referring to fig. 1, in one embodiment, the over-current detection module further includes a capacitor C1 and a capacitor C2, the first end of the resistor R5 is further configured to be grounded through the capacitor C1, and the inverting input terminal of the voltage comparator U3 is further configured to be grounded through the capacitor C2. The filter capacitor C1 is arranged at the non-inverting input end of the voltage comparator U3, and the filter capacitor C2 is arranged at the inverting input end of the voltage comparator U3, so that the input end of the voltage comparator U3 can be prevented from being interfered by alternating-current clutter signals.
Referring to fig. 2, in one embodiment, the thyristor short-circuit protection circuit further includes a capacitor C3 and a processing module, the reset terminal of the time base integration module is used for being connected to the first power supply, the reset terminal of the time base integration module is further used for being grounded through the capacitor C3, and the reset terminal of the time base integration module is further connected to the control terminal of the processing module. Specifically, when the system is powered on, the capacitor C3 connected to the reset end of the time-base integrated module is charged to generate a pull-down level to force the time-base integrated module to reset, and after the time-base integrated module is reset, the output end of the time-base integrated module outputs a low-level signal, so that the output end of the photoelectric coupler U1 is in a cut-off state, the corresponding triode Q2 is in a cut-off state, and the emitter of the triode Q2 outputs 0V voltage. Further, after the time-base integrated module is reset, the discharging end of the time-base integrated module is grounded, that is, the time-base integrated module discharges to the ground, so that the base of the transistor Q1 is pulled down to 0V, the transistor Q1 is forced to be turned off, and after the time-base integrated module is reset, the triggering end of the time-base integrated module is a high-point screen. In addition, by setting the processing module, the processing module outputs a reset signal to reset the time base integration module, so that a user can control the time base integration module to be reset.
Referring to fig. 2, in one embodiment, the thyristor short-circuit protection circuit further includes a resistor R6 and a resistor R7, the output terminal of the time-base integration module is connected to the first input terminal of the photocoupler U1 through the resistor R6, the output terminal of the time-base integration module is further connected to the first terminal of the resistor R7, and the second terminal of the resistor R7 is used for grounding. Specifically, by arranging the voltage dividing resistor R6 and the resistor R7, the voltage output by the output end of the time base integration module is frequently divided and then transmitted to the first input end of the photocoupler U1, so as to better protect the photocoupler U1. In one embodiment, the Processing module is a Central Processing Unit (CPU).
Referring to fig. 2, in one embodiment, the thyristor short-circuit protection circuit further includes a resistor R8, a second terminal of the resistor R7 is configured to be grounded through the resistor R8, and the detection terminal of the processing module is connected to the second terminal of the resistor R7. Specifically, the resistor R8 is arranged, so that the voltage output by the time base integration module is further subjected to voltage division processing, the processing module is used for detecting whether the time base integration module outputs a high level signal, namely, the processing module can detect whether the triode Q2 outputs a driving voltage, namely, whether a thyristor is short-circuited or not is judged by an output voltage return signal to the processing module, and the fault is processed in time.
Referring to fig. 2, in one embodiment, the control terminal of the processing module is connected to the collector of the transistor Q1, and the processing module is configured to transmit an on-drive signal to the trigger terminal of the time-based integrated module, at this time, the voltage of the trigger terminal of the time-based integrated module is pulled down instantaneously, the power generation terminal of the time-based integrated module discharges to ground and becomes an open circuit to ground, so that the base of the transistor Q1 receives a high-level signal, so that the transistor Q1 is in a saturated conduction state, the trigger terminal voltage of the time-based integrated module is pulled down all the time, so that the output terminal of the time-based integrated module outputs the high-level signal, and the emitter of the transistor Q2 outputs the drive voltage. That is, when the processing module outputs the on driving signal, the emitter of the transistor Q2 can be enabled to transmit the driving voltage, so that the thyristor operates normally. For example, after the short-circuit fault of the thyristor is relieved, the control end of the control processing module can output an on-drive signal, so that the thyristor can be normally powered and normally work. In one embodiment, the thyristor short-circuit protection circuit further includes a capacitor C5, the control terminal of the processing module is used for being grounded through a capacitor C5, and the capacitor C5 in this embodiment plays a role in filtering.
Referring to fig. 1, in one embodiment, the thyristor short-circuit protection circuit further includes a voltage regulator DW1 and a capacitor C4, a base of the transistor Q2 is further used for being grounded through the capacitor C4, an anode of the voltage regulator DW1 is used for being grounded, and a cathode of the voltage regulator DW1 is connected to a base of the transistor Q2. By arranging the voltage regulator tube DW1 and the capacitor C4, when the first output end and the second output end of the photoelectric coupler U1 are in a conducting state, the voltage of a second power supply is filtered by the voltage regulator tube DW1 and the capacitor C4 and then is transmitted to the base electrode of the triode Q2, so that the triode Q2 is better driven to be in a conducting state, and the influence of noise interference signals on the conducting state of the triode Q2 is avoided.
Referring to fig. 1, in one embodiment, the thyristor short-circuit protection circuit further includes a resistor R9 and a light emitting diode LED1, an emitter of the transistor Q2 is connected to an anode of the light emitting diode LED1 through the resistor R9, and a cathode of the light emitting diode LED1 is used for grounding. Specifically, by providing the resistor R9 and the light emitting diode LED1 on the emitter of the transistor Q2, when the emitter of the diode Q2 outputs the driving voltage, the light emitting diode LED1 is powered on and shines to send an operation instruction, which indicates that the thyristor is in a normal operation state.
Referring to fig. 1, in one embodiment, the thyristor short-circuit protection circuit further includes a capacitor C6 and a capacitor C7, and the emitter of the transistor Q2 is further grounded through the capacitor C6 and the capacitor C7, respectively, wherein the capacitor C6 and the capacitor C7 play a role of filtering. In one embodiment, the capacitor C7 is an aluminum capacitor.
In one embodiment, a thyristor short-circuit protection device is provided, which comprises the thyristor short-circuit protection circuit described in any one of the above embodiments. Referring to fig. 1, in one embodiment, the thyristor short-circuit protection circuit includes: the overcurrent detection module, the time base integration module, the triode Q1, the triode Q2, the resistor R1 and the photoelectric coupler U1; the input end of the over-current detection module is used for being connected with a phase line over-current detection point, the output end of the over-current detection module is connected with the base of the triode Q1, the emitter of the triode Q1 is used for being grounded, the collector of the triode Q1 is connected with the trigger end of the time-base integration module, the trigger end of the time-base integration module is also used for being connected with a first power supply, the discharge end of the time-base integration module is connected with the base of the triode Q1, the output end of the time-base integration module is connected with the first input end of the photoelectric coupler U1, the second input end of the photoelectric coupler U1 is used for being grounded, the first output end of the photoelectric coupler U1 is used for being connected with a second power supply, the second output end of the photoelectric coupler U1 is also connected with the collector of the triode Q2, and the first output end of the photoelectric coupler U1 is connected with the base of the triode Q2, the emitter of the triode Q2 is used for being connected with the driving end 300 of the thyristor; the overcurrent detection module is used for outputting a first control signal when detecting that an interphase short circuit occurs, so that the triode Q1 is in a cut-off state.
In the thyristor short-circuit protection device, when the thyristor has a short-circuit fault, the overcurrent detection module outputs a first control signal to enable the triode Q1 to be in a cut-off state, the trigger end of the time-base integrated module receives a high-level signal to enable the state of the time-base integrated module to be turned over, the output end of the time-base integrated module outputs 0V, namely the first input end of the photoelectric coupler U1 receives 0V voltage, the first output end and the second output end of the photoelectric coupler U1 are in a cut-off state, further the triode Q2 is in a cut-off state, the output voltage of the emitter of the triode Q2 is 0V, so that the thyristor is de-energized, namely after the thyristor has a short-circuit fault, the circuit can automatically cut off the power supply of a thyristor driving circuit, thereby protecting the thyristor, and in addition, the input and output electric signals of the photoelectric coupler U36, the control end and the controlled end of the circuit are isolated from each other, so that the control end of the circuit is better protected from being damaged by strong current interference.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (9)
1. A thyristor short circuit protection circuit, comprising: the device comprises an overcurrent detection module, a time base integration module, a triode Q1, a triode Q2, a resistor R1 and a photoelectric coupler;
the input end of the over-current detection module is used for being connected with a phase line over-current detection point, the output end of the over-current detection module is connected with the base electrode of the triode Q1, the emitting electrode of the triode Q1 is used for being grounded, the collecting electrode of the triode Q1 is connected with the triggering end of the time-base integrated module, the triggering end of the time-base integrated module is also used for being connected with a first power supply, the discharging end of the time-base integrated module is connected with the base electrode of the triode Q1, the output end of the time-base integrated module is connected with the first input end of the photoelectric coupler, the second input end of the photoelectric coupler is used for being grounded, the first output end of the photoelectric coupler is used for being connected with a second power supply, the first output end of the photoelectric coupler is also connected with the collecting electrode of the triode Q2, and the second output end of the photoelectric coupler is connected with the base electrode, the emitter of the triode Q2 is used for being connected with the driving end of the thyristor;
the overcurrent detection module is used for outputting a first control signal when detecting that an interphase short circuit occurs, so that the triode Q1 is in a cut-off state;
the over-current detection module comprises a diode D1, a diode D2, a diode D3, a resistor R2, a resistor R3 and a voltage comparator, the positive phase input end of the voltage comparator is used for being connected with a third power supply, the positive phase input end of the voltage comparator is respectively connected with the anode of the diode D1, the anode of the diode D2 and the anode of the diode D3, the cathode of the diode D1 is used for connecting an A phase line overcurrent detection point, the cathode of the diode D2 is used for connecting a B phase line overcurrent detection point, the cathode of the diode D3 is used for connecting the over-current detection point of the C phase line, the inverting input end of the voltage comparator is used for connecting the fourth power supply, the output end of the voltage comparator is connected with the base of the triode Q1 through the resistor R2, the base of the transistor Q1 is also connected to ground through the resistor R3, wherein the voltage value of the third power supply is greater than the voltage value of the fourth power supply.
2. The thyristor short-circuit protection circuit of claim 1, wherein the over-current detection module further comprises a resistor R4 and a resistor R5, the positive-phase input terminal of the voltage comparator is configured to be connected to the third power supply through the resistor R4, the positive-phase input terminal of the over-current detection module is further connected to the first terminal of the resistor R5, and the second terminal of the resistor R5 is respectively connected to the anode of the diode D1, the anode of the diode D2, and the anode of the diode D3.
3. The thyristor short-circuit protection circuit of claim 2, wherein the over-current detection module further comprises a capacitor C1 and a capacitor C2, the first terminal of the resistor R5 is further configured to be grounded through the capacitor C1, and the inverting input terminal of the voltage comparator is further configured to be grounded through the capacitor C2.
4. The thyristor short-circuit protection circuit of claim 1, further comprising a capacitor C3 and a processing module, wherein the reset terminal of the time base integration module is configured to be connected to the first power supply, the reset terminal of the time base integration module is further configured to be grounded via the capacitor C3, and the reset terminal of the time base integration module is further connected to the control terminal of the processing module.
5. The thyristor short-circuit protection circuit of claim 4, further comprising a resistor R6 and a resistor R7, wherein the output terminal of the time base integration module is connected to the first input terminal of the optocoupler through the resistor R6, the output terminal of the time base integration module is further connected to the first terminal of the resistor R7, and the second terminal of the resistor R7 is connected to ground.
6. The thyristor short-circuit protection circuit of claim 5, further comprising a resistor R8, wherein the second terminal of the resistor R7 is configured to be grounded via the resistor R8, and the detection terminal of the processing module is connected to the second terminal of the resistor R7.
7. The thyristor short-circuit protection circuit of claim 1, further comprising a voltage regulator DW1 and a capacitor C4, wherein the base of the transistor Q2 is further configured to be grounded through the capacitor C4, the positive electrode of the voltage regulator DW1 is configured to be grounded, and the negative electrode of the voltage regulator DW1 is connected to the base of the transistor Q2.
8. The thyristor short-circuit protection circuit of claim 1, further comprising a resistor R9 and a light emitting diode LED1, wherein the emitter of the transistor Q2 is connected to the anode of the light emitting diode LED1 through the resistor R9, and the cathode of the light emitting diode LED1 is connected to ground.
9. A thyristor short-circuit protection device comprising a thyristor short-circuit protection circuit as claimed in any one of claims 1 to 8.
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| CN202010702370.5A CN111786354B (en) | 2020-07-21 | 2020-07-21 | Thyristor short-circuit protection circuit and device |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105226611A (en) * | 2015-11-11 | 2016-01-06 | 国网黑龙江省电力有限公司管理培训中心 | Short circuit/the overload protecting circuit of single-phase transformer |
| CN209327549U (en) * | 2018-09-29 | 2019-08-30 | 杭州之山智控技术有限公司 | Three phase supply servo detection of power loss improves circuit |
| CN210090544U (en) * | 2019-02-28 | 2020-02-18 | 北京航天科达科技有限公司 | Isolated direct current voltage sampling circuit |
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2020
- 2020-07-21 CN CN202010702370.5A patent/CN111786354B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105226611A (en) * | 2015-11-11 | 2016-01-06 | 国网黑龙江省电力有限公司管理培训中心 | Short circuit/the overload protecting circuit of single-phase transformer |
| CN209327549U (en) * | 2018-09-29 | 2019-08-30 | 杭州之山智控技术有限公司 | Three phase supply servo detection of power loss improves circuit |
| CN210090544U (en) * | 2019-02-28 | 2020-02-18 | 北京航天科达科技有限公司 | Isolated direct current voltage sampling circuit |
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