CN113725817A - Alternating current input sudden change protection circuit - Google Patents
Alternating current input sudden change protection circuit Download PDFInfo
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- CN113725817A CN113725817A CN202111024833.8A CN202111024833A CN113725817A CN 113725817 A CN113725817 A CN 113725817A CN 202111024833 A CN202111024833 A CN 202111024833A CN 113725817 A CN113725817 A CN 113725817A
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- protection circuit
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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
- H02H7/10—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 converters; for rectifiers
- H02H7/12—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 converters; for rectifiers for static converters or rectifiers
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
- H02H9/04—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage
- H02H9/045—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage adapted to a particular application and not provided for elsewhere
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/32—Means for protecting converters other than automatic disconnection
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
The invention relates to the technical field of power grids, in particular to an alternating current input sudden change protection circuit which comprises a protection circuit, a voltage limiting circuit and a voltage regulating circuit, wherein the protection circuit is used for inputting voltage to a bus capacitor to form a passage, and when the input voltage suddenly becomes large, the voltage of the input side of a PFC circuit is clamped at the bus voltage; the input voltage detection circuit is used for detecting the change of the input voltage and switching off the switching tube of the PFC level circuit according to the detection result; the bus voltage detection circuit is used for detecting the change of the bus voltage; and the bleeder circuit is used for driving the switching tube to discharge according to the detection result of the bus voltage detection circuit so as to reduce the bus voltage and stop discharging when the voltage is reduced to a set value. The invention can effectively protect the circuit of the working condition that the N line and L2 or L3 are short-circuited in the power grid, and can protect the input measurement switch tube and the bus capacitor, thereby having strong market application prospect.
Description
Technical Field
The invention relates to the technical field of power grids, in particular to an alternating current input sudden change protection circuit.
Background
The power grid generally comprises three live wires L1, L2 and L3, a zero wire N and a ground wire PE, for a single-phase input power supply, two phases of alternating current input are assumed to be an L1 wire and an N wire respectively, when the power grid fails and the N wire is in short circuit with the L2 or the L3, the input voltage of the power supply is changed into line voltage from the phase voltage of the power grid, the voltage amplitude is changed into 1.732 times of the original voltage amplitude, and the duration is millisecond-level.
The existing scheme mainly adopts a piezoresistor and a gas discharge tube for protection, mainly aims at microsecond lightning surge faults, the piezoresistor generally has use times, a circuit can be out of work after discharging for many times, in addition, the prior art does not specially protect a switch tube and a rear-stage bus capacitor, and the switch tube and the rear-stage bus capacitor are easily damaged in actual working conditions.
Disclosure of Invention
The invention discloses an alternating current input sudden change protection circuit, aiming at overcoming the defects of the prior art, and solving the problems that when a piezoresistor and a gas discharge tube are adopted for protection in the prior art, the piezoresistor is generally used for times, and the circuit fails after multiple discharges, and the prior art does not specially protect a switching tube and a post-stage bus capacitor, so that the switching tube and the post-stage bus capacitor are easily damaged in the actual working condition.
The invention is realized by the following technical scheme:
the invention provides an AC input sudden change protection circuit, which comprises
A protection circuit for forming a path for an input voltage to the bus capacitor so that an input side voltage of the PFC circuit is clamped at the bus voltage when the input voltage suddenly becomes large;
the input voltage detection circuit is used for detecting the change of the input voltage and switching off the switching tube of the PFC level circuit according to the detection result;
the bus voltage detection circuit is used for detecting the change of the bus voltage;
and the bleeder circuit is used for driving the switching tube to discharge according to the detection result of the bus voltage detection circuit so as to reduce the bus voltage and stop discharging when the voltage is reduced to a set value.
Furthermore, the protection circuit adopts a plurality of diode combinations or a single rectifier bridge, so that the input voltage forms a path to the bus capacitor, and when the input voltage suddenly becomes large, the input current charges the bus capacitor, so that the voltage is clamped at the bus voltage on the input side of the PFC circuit.
Furthermore, if there is an anti-parallel diode of MOS connected in parallel with the diode in the PFC stage, this diode can be eliminated.
Further, the input voltage detection circuit includes a voltage detection circuit and a comparison circuit.
Furthermore, the preceding-stage voltage sampling of the voltage detection circuit selects a differential circuit or a sampling chip, and when the differential circuit is used for sampling, the same-direction input end of the operational amplifier is provided with bias voltage, so that the output voltage is greater than 0V.
Furthermore, the comparison circuit adopts an operational amplifier comparator or other control chips, is connected to a driving chip enabling pin of the PFC stage switching tube, and outputs the driving for turning off the PFC stage switching tube.
Furthermore, the operational amplifier comparator is used for dealing with the sudden change of the input voltage to the positive large voltage and the sudden change of the input voltage to the negative large voltage.
Furthermore, the front stage of the bus voltage detection circuit adopts a differential circuit or a sampling chip for sampling, and the rear stage comparison circuit adopts an operational amplifier comparator or other control chips.
Furthermore, the comparison circuit outputs a drive for the switching tube of the bleeder circuit, when the bus voltage is greater than a threshold value, the switching tube is switched on, the discharging is carried out through the bleeder circuit, the bus voltage is reduced, and when the bus voltage is reduced to a set value, the switching tube is switched off.
Furthermore, when the alternating current input sudden change protection circuit is applied, one or more of a protection circuit, a bus voltage detection circuit and a bleeder circuit is selected.
The invention has the beneficial effects that:
the invention can effectively protect the circuit of the working condition that the N line and L2 or L3 are short-circuited in the power grid. When a power grid fails, the input voltage suddenly increases, the increased input voltage enters the bus capacitor through a diode in the protection circuit to protect the switching tube on the input side, the switching tube is closed on hardware at microsecond level according to the change of the input voltage, and when the voltage of the bus capacitor exceeds the rated voltage, the bus capacitor is discharged in a hardware protection mode. When the voltage of the bus capacitor is reduced to a certain degree, the discharge of the bus capacitor is stopped, and the method has a very strong market application prospect.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic block diagram of an AC input glitch protection circuit;
FIG. 2 is a schematic diagram of an AC input glitch protection circuit;
FIG. 3 is a circuit diagram of an input voltage detection and waveform sealing circuit according to an embodiment of the present invention;
FIG. 4 is a circuit diagram of bus voltage detection and wave sealing according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
The present embodiment discloses an ac input abrupt change protection circuit shown in fig. 1 and 2, which includes a protection circuit, an input voltage detection circuit, a bus voltage detection circuit, and a bleeder circuit.
The protection circuit of the embodiment is used for forming a path from an input voltage to a bus capacitor, and clamping the input side voltage of the PFC circuit at the bus voltage when the input voltage suddenly becomes large;
the protection circuit of the embodiment is used for detecting the change of the input voltage and switching off the switching tube of the PFC stage circuit according to the detection result;
the bus voltage detection circuit of the embodiment is used for detecting the change of the bus voltage;
the bleeder circuit of the embodiment is used for driving the switching tube to discharge according to the detection result of the bus voltage detection circuit so as to reduce the bus voltage and stop discharging when the voltage is reduced to a set value.
The embodiment solves the problems that in the prior art, a piezoresistor and a gas discharge tube are adopted for protection, the piezoresistor is generally limited in use times when protection is carried out mainly aiming at microsecond-level lightning surge faults, and a circuit can fail after multiple discharges.
The embodiment specially protects the switch tube and the post-stage bus capacitor, and the safety of the circuit is improved.
Example 2
In a specific implementation aspect, the present embodiment provides a protection circuit, which employs four diodes or a rectifier bridge, so that an input voltage forms a path to a bus capacitor, and when the input voltage suddenly becomes large, an input current charges the bus capacitor through D1-D4, so that a voltage on an input side of a PFC circuit is clamped at a bus voltage.
In this embodiment, if there is an anti-parallel diode of MOS connected in parallel with the diode in the PFC stage circuit, this diode may be eliminated, for example, D3 and D4 may be eliminated in the actual exemplary circuit.
Example 3
In a specific implementation aspect, the present embodiment provides an input voltage detection circuit, as shown in fig. 3, the input voltage detection circuit is mainly used to detect a change of an input voltage, and then perform a switching-off driving of a switching tube of a PFC stage circuit.
The input voltage detection circuit mainly comprises a voltage detection part and a comparison part, wherein the preceding-stage voltage sampling can adopt a differential circuit for sampling in order to quickly respond to the input voltage, and can also adopt other sampling chips for sampling.
When the differential circuit is adopted for sampling, a bias voltage is added to the equidirectional input end of the operational amplifier, so that the output voltage is more than 0V.
The post-stage comparison circuit of the embodiment can adopt an operational amplifier comparator and also can adopt other control chips.
The comparison circuit of the embodiment adopts two comparators, which mainly correspond to the situation that when the input voltage suddenly changes, the input voltage may suddenly change to a positive large voltage or suddenly change to a negative large voltage.
The embodiment U2A mainly deals with sudden change of the input voltage to a positive large voltage, and U2B mainly deals with sudden change of the input voltage to a negative large voltage.
The protection value of the input voltage of the present embodiment is determined by R18, R21, R22. The output of the comparison circuit is used for switching off the drive of the PFC stage switching tube, and can be connected to an enabling pin of a drive chip of the PFC stage switching tube and also can be connected with a drive signal in an AND mode.
The input voltage detecting and wave-sealing circuit of the present embodiment only shows the driving circuit of Q1Q 2, and the driving circuit of Q3Q 4 is similar to the driving circuit of Q1Q 2.
Example 4
In a specific implementation aspect, the present embodiment provides a bus voltage detection circuit and a bleeder circuit, and as shown in fig. 4, the bus voltage detection circuit of the present embodiment is mainly used for detecting a change of a bus voltage and finally driving a switching tube of the bleeder circuit.
The preceding stage of this embodiment bus voltage detection circuit can adopt differential circuit sampling for the quick response bus voltage, also can adopt other sampling chips to sample, and the comparator can also adopt other control chips to put the comparator to the back-end comparison circuit adoption fortune, and the comparison circuit output is used for the drive of bleeder circuit switch pipe.
The switch tube of the embodiment can adopt a MOSFET, an IGBT or other fully-controlled switch devices, and the resistor R6 can be selected according to the input voltage and the size of the bus capacitor.
In this embodiment, when the bus voltage is greater than a certain value, Q5 is turned on, and discharge is performed through the bleed circuit, the bus voltage decreases, and when the bus voltage decreases to a certain extent, Q5 is turned off.
The embodiment enables the bus voltage to be always in a controllable range, and ensures the normal operation of a circuit at the rear stage.
The protection threshold of the present embodiment is determined by R17, R19, R20.
Example 5
In practical applications, all four parts of the circuit may be adopted, or only some of the circuit may be adopted, and may be arranged and combined, for example, only the protection circuit, or the protection circuit and the input voltage detection circuit are provided.
In conclusion, the invention can effectively protect the circuit for the working condition that the N line and the L2 or the L3 are short-circuited in the power grid. When a power grid fails, the input voltage suddenly increases, the increased input voltage enters the bus capacitor through a diode in the protection circuit to protect the switching tube on the input side, the switching tube is closed on hardware at microsecond level according to the change of the input voltage, and when the voltage of the bus capacitor exceeds the rated voltage, the bus capacitor is discharged in a hardware protection mode. When the voltage of the bus capacitor is reduced to a certain degree, the discharge of the bus capacitor is stopped, and the method has a very strong market application prospect.
The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (9)
1. An AC input sudden change protection circuit is characterized by comprising
A protection circuit for forming a path for an input voltage to the bus capacitor so that an input side voltage of the PFC circuit is clamped at the bus voltage when the input voltage suddenly becomes large;
the input voltage detection circuit is used for detecting the change of the input voltage and switching off the switching tube of the PFC level circuit according to the detection result;
the bus voltage detection circuit is used for detecting the change of the bus voltage;
and the bleeder circuit is used for driving the switching tube to discharge according to the detection result of the bus voltage detection circuit so as to reduce the bus voltage and stop discharging when the voltage is reduced to a set value.
2. An ac input protection circuit of claim 1, wherein the protection circuit employs a plurality of diode combinations or a single rectifier bridge to route the input voltage to the bus capacitor.
3. An ac input protection circuit of claim 1, wherein the input voltage detection circuit comprises a voltage detection circuit and a comparison circuit.
4. An AC input sudden change protection circuit according to claim 3, characterized in that the preceding stage voltage sampling of the voltage detection circuit selects a differential circuit or a sampling chip, and when the differential circuit sampling is performed, the same-direction input end of the operational amplifier is provided with a bias voltage, so that the output voltage is greater than 0V.
5. An ac input sudden change protection circuit according to claim 3, wherein the comparison circuit is an operational amplifier comparator or other control chip, and is connected to the enable pin of the driving chip of the PFC stage switching tube, and its output is used to turn off the driving of the PFC stage switching tube.
6. An ac input protection circuit as claimed in claim 5, wherein the operational amplifier comparator is configured to cope with sudden input voltage changes to a positive large voltage and sudden input voltage changes to a negative large voltage.
7. An alternating current input sudden change protection circuit according to claim 1, characterized in that a differential circuit or a sampling chip is adopted at a front stage of the bus voltage detection circuit for sampling, and an operational amplifier comparator or other control chips is adopted at a rear stage of the bus voltage detection circuit.
8. An ac input surge protection circuit according to claim 7, wherein the comparator circuit outputs a drive for the bleeder circuit switching tube, the switching tube conducting to discharge through the bleeder circuit when the bus voltage is greater than the threshold, the bus voltage decreasing, and the switching tube turning off when the bus voltage decreases to the set point.
9. An ac input sudden change protection circuit according to claim 1, wherein when the ac input sudden change protection circuit is applied, one or more of a protection circuit, an input voltage detection circuit, a bus voltage detection circuit, and a bleeder circuit are selected.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111024833.8A CN113725817A (en) | 2021-09-02 | 2021-09-02 | Alternating current input sudden change protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111024833.8A CN113725817A (en) | 2021-09-02 | 2021-09-02 | Alternating current input sudden change protection circuit |
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| Publication Number | Publication Date |
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| CN113725817A true CN113725817A (en) | 2021-11-30 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202111024833.8A Pending CN113725817A (en) | 2021-09-02 | 2021-09-02 | Alternating current input sudden change protection circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024055913A1 (en) * | 2022-09-13 | 2024-03-21 | 中兴通讯股份有限公司 | Surge protection method and circuit |
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2021
- 2021-09-02 CN CN202111024833.8A patent/CN113725817A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024055913A1 (en) * | 2022-09-13 | 2024-03-21 | 中兴通讯股份有限公司 | Surge protection method and circuit |
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