CN113488961A - Over-voltage and under-voltage protection circuit and over-voltage and under-voltage protection device - Google Patents
Over-voltage and under-voltage protection circuit and over-voltage and under-voltage protection device Download PDFInfo
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- CN113488961A CN113488961A CN202110890152.3A CN202110890152A CN113488961A CN 113488961 A CN113488961 A CN 113488961A CN 202110890152 A CN202110890152 A CN 202110890152A CN 113488961 A CN113488961 A CN 113488961A
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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
- H02H3/20—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 voltage
- H02H3/207—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 voltage also responsive to under-voltage
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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
- H02H3/02—Details
- H02H3/06—Details with automatic reconnection
- H02H3/066—Reconnection being a consequence of eliminating the fault which caused disconnection
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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
- H02H3/24—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 undervoltage or no-voltage
-
- 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
- H02H3/24—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 undervoltage or no-voltage
- H02H3/253—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 undervoltage or no-voltage for multiphase applications, e.g. phase interruption
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Abstract
The application is suitable for the field of power supply control, and provides an over-voltage and under-voltage protection circuit and an over-voltage and under-voltage protection device. The overvoltage and undervoltage protection circuit comprises N sampling judgment modules and a switch module, wherein each sampling judgment module comprises a sampling unit, an overvoltage judgment unit and an undervoltage judgment unit; the sampling unit is connected with the input power supply, the input end of the overvoltage judging unit and the input end of the undervoltage judging unit, the output end of the overvoltage judging unit and the output end of the undervoltage judging unit are respectively connected with the control end of the switch module, and the switch module is connected between the input power supply and an external load. The overvoltage and undervoltage protection circuit detects the voltage of the input power supply through the sampling unit, judges whether overvoltage or phase failure occurs in the circuit through the overvoltage judging unit and the undervoltage judging unit, disconnects the input power supply and the load to protect the load when undervoltage or phase failure occurs, and can establish connection between the input power supply and the load after the circuit is normal so that the circuit can automatically recover to work.
Description
Technical Field
The application relates to the field of power supply control, in particular to an overvoltage and undervoltage protection circuit and an overvoltage and undervoltage protection device.
Background
In a three-phase power circuit, the condition of overvoltage, undervoltage or phase failure often occurs, which causes great influence on the operation of a load; in order to solve the problem in the prior art, a circuit breaker is usually adopted, and when the overvoltage/undervoltage or the phase failure is detected, the circuit breaker disconnects the power supply from the load, so that the load is prevented from being damaged, and the mode cannot automatically recover the connection between the power supply and the load.
Disclosure of Invention
The application mainly aims to provide an over-voltage and under-voltage protection circuit and an over-voltage and under-voltage protection device, and aims to solve the problem that in the prior art, after circuit breaking, connection between a power supply and a load cannot be automatically recovered.
In order to achieve the above object, the present application provides an over-voltage and under-voltage protection circuit, where the over-voltage and under-voltage protection circuit includes N (N is greater than or equal to 1 and N is an integer) sampling judgment modules and a switch module, and the sampling judgment module includes a sampling unit, an over-voltage judgment unit, and an under-voltage judgment unit; the sampling end of the sampling unit is connected with an input power supply, the output end of the sampling unit is respectively connected with the input end of the overvoltage judging unit and the input end of the undervoltage judging unit, the output end of the overvoltage judging unit and the output end of the undervoltage judging unit are respectively connected with the control end of the switch module, and the switch module is connected between the input power supply and an external load; wherein:
the sampling unit is used for detecting the voltage of the input power supply and respectively sending a first detection signal to the overvoltage judging unit and the undervoltage judging unit according to the detected voltage;
the overvoltage judging unit is used for judging whether overvoltage occurs according to the first detection signal and sending a first power-off signal to the switch module when the overvoltage occurs;
the undervoltage judging unit is used for judging whether undervoltage or open-phase occurs according to the first detection signal and sending a second power-off signal to the switch module when the undervoltage or open-phase occurs;
the switch module is used for disconnecting the input power supply from the external load when receiving the first power-off signal and/or the second power-off signal, and keeping the connection between the input power supply and the external load when not receiving the first power-off signal and not receiving the second power-off signal.
Optionally, the overvoltage judging unit includes a reference voltage output subunit, a comparing subunit, and a voltage division filtering subunit; wherein:
the input end of the voltage division filtering subunit is connected with the output end of the sampling unit, the output end of the voltage division filtering subunit is connected with the first input end of the comparison subunit, and the voltage division filtering subunit is used for performing voltage division filtering on the first detection signal and outputting a first current voltage to the comparison subunit;
the output end of the reference voltage output subunit is connected with the second input end of the comparison subunit, and the reference voltage output subunit is used for setting and providing reference voltage;
and the output end of the comparison subunit is connected with the control end of the switch module, and the comparison subunit is used for comparing the first current voltage with the reference voltage and sending the first power-off signal to the switch module when the first current voltage is greater than the reference voltage. Optionally, the reference voltage output subunit includes a first resistor and a second resistor; wherein:
the first resistor is connected between the comparison subunit and a power supply; the second resistor is connected between the comparison subunit and ground.
Optionally, the comparison subunit includes a first comparator, a third resistor, and a fourth resistor; wherein:
the inverting input end of the first comparator is connected with the output end of the voltage division filtering subunit; the non-inverting input end of the first comparator is connected with the output end of the reference voltage output subunit, and the non-inverting input end of the first comparator is also connected with the output end of the first comparator through the third resistor; the output end of the first comparator is connected with the power supply through the fourth resistor, and the output end of the first comparator is the output end of the overvoltage judging unit.
Optionally, the reference voltage output subunit includes a first diode, a fifth resistor, and a sixth resistor; wherein:
the positive pole of the first diode is connected with the output end of the sampling unit, the negative pole of the first diode is connected with the first end of the sixth resistor, the second end of the sixth resistor is connected with the inverted input end of the first comparator, and the second end of the sixth resistor is grounded through the fifth resistor.
Optionally, the under-voltage determining unit includes a second comparator, a variable resistor, a seventh resistor, an eighth resistor, and a ninth resistor; wherein:
the non-inverting input end of the second comparator is connected with the output end of the sampling unit through the seventh resistor, and the non-inverting input end of the second comparator is also connected with the output end of the second comparator through the eighth resistor;
the inverting input end of the second comparator is connected with a power supply through the ninth resistor, and the inverting input end of the second comparator is grounded through the variable resistor;
the output end of the second comparator is the output end of the undervoltage judging unit.
Optionally, N is equal to 3, the input power supply is a three-phase power supply, and each sampling judgment module is respectively connected between one-phase output of the input power supply and the switch module.
Optionally, the switch module comprises a relay, a contactor, a switch tube, a second diode, a third diode, a tenth resistor, an eleventh resistor and a twelfth resistor; wherein:
the control end of the switch tube is grounded through the tenth resistor, the control end of the switch tube is further connected with the first end of the eleventh resistor, the second end of the eleventh resistor is connected with the anode of the second diode, the cathode of the second diode is connected with the sampling judgment module, and the second end of the eleventh resistor is further connected with a power supply through the twelfth resistor;
the output end of the switch tube is grounded;
the input end of the switching tube is connected with the anode of the third diode, the cathode of the third diode is connected with the power supply, the coil of the relay is connected with the third diode in parallel, and a group of normally open contacts of the relay are connected in series in a coil loop of the contactor;
the contactor comprises three groups of normally open contacts, and each group of normally open contacts is respectively connected between the input power supply and an external load. Optionally, the circuit further includes a power supply, where the power supply includes a voltage-reducing chip, a fourth diode, a second capacitor, a third electrolytic capacitor, and a fourth electrolytic capacitor; wherein:
the input end of the voltage reduction chip is connected with the cathode of the fourth diode, the anode of the fourth diode is connected with the output end of the voltage reduction rectifier unit, the input end of the voltage reduction chip is also connected with the anode of the third electrolytic capacitor, and the cathode of the third electrolytic capacitor is grounded;
the output end of the voltage reduction chip is the output end of the power supply, the output end of the voltage reduction chip is also connected with the anode of the fourth electrolytic capacitor, the cathode of the fourth electrolytic capacitor is grounded, and the output end of the voltage reduction chip is also grounded through the second capacitor;
and the grounding end of the voltage reduction chip is grounded.
In addition, for realizing above-mentioned purpose, this application still provides an cross undervoltage protection device, cross undervoltage protection device include the casing and as above cross undervoltage protection circuit, cross undervoltage protection circuit set up in the casing.
The application provides an cross undervoltage protection circuit and cross undervoltage protection device. The overvoltage and undervoltage protection circuit detects the voltage of the input power supply through the sampling unit, judges whether overvoltage or phase failure occurs in the circuit through the overvoltage judging unit and the undervoltage judging unit, disconnects the input power supply and the load to protect the load when undervoltage or phase failure occurs, and can establish connection between the input power supply and the load after the circuit is normal so that the circuit can automatically recover to work.
Drawings
In order to more clearly illustrate the embodiments of the present application 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 application, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.
FIG. 1 is a functional block diagram of an embodiment of an under-voltage protection circuit of the present application;
FIG. 2 is a functional block diagram of another embodiment of the under-voltage protection circuit of the present application;
fig. 3 is a circuit structure diagram of the under-voltage protection circuit applied in the embodiment of fig. 2.
The implementation, functional features and advantages of the objectives of the present application will be further explained with reference to the accompanying drawings.
The reference numbers illustrate:
Detailed Description
It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
The technical solutions in the embodiments of the present application will be described clearly and completely with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. 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 application.
It should be noted that all directional indicators (such as up, down, left, right, front, and back) in the embodiments of the present application are only used to explain the relative position relationship between the components, the motion situation, and the like in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indicator is changed accordingly.
In addition, the descriptions referred to as "first", "second", etc. in this application are for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicit ly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present application.
The embodiment of the application provides an overvoltage and undervoltage protection circuit, which can be applied to the rear end of power supply equipment or the front end of electric equipment, for example, can be applied to the front end of a three-phase uninterruptible power supply to protect the three-phase uninterruptible power supply. Referring to fig. 1, fig. 1 is a functional block diagram of an embodiment of an under-voltage protection circuit of the present application. In this embodiment, the over-voltage and under-voltage protection circuit includes an over-voltage and under-voltage protection circuit including N (N is greater than or equal to 1 and N is an integer) sampling judgment modules 200 and a switch module 100, where the sampling judgment module 200 includes a sampling unit 210, an over-voltage judgment unit 220, and an under-voltage judgment unit 230; the sampling end of the sampling unit 210 is connected with the input power supply, the output end of the sampling unit 210 is respectively connected with the input end of the overvoltage judging unit 220 and the input end of the undervoltage judging unit 230, the output end of the overvoltage judging unit 220 and the output end of the undervoltage judging unit 230 are respectively connected with the control end of the switch module 100, and the switch module 100 is connected between the input power supply and the external load; wherein:
the sampling unit 210 is configured to detect a voltage of an input power supply, and respectively send a first detection signal to the overvoltage judging unit 220 and the undervoltage judging unit 230 according to the detected voltage;
the overvoltage judging unit 220 is configured to judge whether an overvoltage occurs according to the first detection signal, and send a first power-off signal to the switch module 100 when the overvoltage occurs;
the undervoltage judging unit 230 is configured to judge whether undervoltage or open-phase occurs according to the first detection signal, and send a second power-off signal to the switch module 100 when undervoltage or open-phase occurs;
the switch module 100 is configured to disconnect the input power supply from the external load when receiving the first power-off signal and/or the second power-off signal, and maintain the connection between the input power supply and the external load when not receiving the first power-off signal and not receiving the second power-off signal.
The overvoltage judging unit 220 judges whether the circuit has overvoltage according to a first detection signal sent by the detected voltage through the sampling unit 210, and controls the switch module 100 to disconnect the input power supply from the external load when the input power supply has overvoltage.
The undervoltage judging unit 230 judges whether the circuit has undervoltage or open phase according to a first detection signal sent by the detected voltage through the sampling unit 210, and controls the switch module 100 to disconnect the input power supply from the external load when the input power supply has undervoltage or open phase;
it should be noted that the sampling unit 210 converts the acquired voltage into the first detection signal through a certain corresponding relationship, for example, a proportional relationship, and obtains a first voltage threshold corresponding to the overvoltage threshold and a second voltage threshold corresponding to the undervoltage threshold through the proportional relationship; the overvoltage judging unit 220 compares the first detection signal with a preset first voltage threshold, determines that the input power supply has overvoltage when the first detection signal is greater than the first voltage threshold, and determines that the circuit has no overvoltage when the first detection signal is less than or equal to the first voltage threshold; the undervoltage determining unit 230 compares the first detection signal with a preset second voltage threshold, determines that the input power is under-voltage or open-phase when the first detection signal is smaller than the second voltage threshold, and determines that the input power is not under-voltage or open-phase when the first detection signal is greater than or equal to the first voltage threshold.
Referring to fig. 2, N in this embodiment is 3, that is, three sampling determination modules 200 are provided, an input power supply is a three-phase power supply, and each sampling determination module 200 is respectively connected between one phase output of the input power supply and the switch module 100.
The switch module 100 is connected to a three-phase output of an input power source and a three-phase power supply interface of an external load.
When the switch module 100 receives a power-off signal sent by any one of the sampling judgment modules 200, the connection between the three-phase output of the input power supply and the three-phase input of the external load power supply interface is disconnected.
In this embodiment, the voltage of the input power is detected by the sampling unit 210, and the overvoltage judging unit and the undervoltage judging unit judge whether the circuit is under-voltage or open-phase, and disconnect the input power and the load to protect the load when under-voltage or open-phase occurs, and meanwhile, the connection between the input power and the load can be established after the circuit is normal, so that the circuit can automatically recover to work.
Further, referring to fig. 3, the overvoltage judging unit includes a reference voltage outputting subunit 221, a comparing subunit 222, and a voltage dividing filtering subunit 223; wherein:
the input end of the voltage division filtering subunit 223 is connected with the output end of the sampling unit 210, the output end of the voltage division filtering subunit 223 is connected with the first input end of the comparison subunit 222, and the voltage division filtering subunit 223 is used for performing voltage division filtering on the first detection signal and outputting the first detection signal as a first current voltage to the comparison subunit 222;
a reference voltage output subunit 221, an output terminal of the reference voltage output subunit 221 being connected to the second input terminal of the comparison subunit 222, the reference voltage output subunit 221 being configured to set and provide a reference voltage;
the output end of the comparison subunit 222 is connected to the control end of the switch module 100, and the comparison subunit 222 is configured to compare the first current voltage with the reference voltage, and send a first power-off signal to the switch module 100 when the first current voltage is greater than the reference voltage.
Since there is a requirement for the input range at the input end of the comparison subunit 222, in order to avoid that the first current voltage output by the sampling unit 210 exceeds the input range of the comparison subunit 222, the voltage division filtering subunit 223 is configured to perform a voltage division operation on the voltage output by the sampling unit 210, so as to ensure that the first current voltage received by the comparison subunit 222 is within the input range. Meanwhile, the voltage division filtering subunit 223 further performs filtering processing on the first current voltage of the output value comparison subunit 222 to filter out interference noise.
The reference voltage output subunit 221 supplies the reference voltage to the comparison subunit 222. It should be noted that the reference voltage is not necessarily an overvoltage value defined by the input power supply; the reference voltage output by the reference voltage output subunit 221 is set corresponding to the voltage division ratio of the voltage division filter subunit 223; specifically, when the input power reaches the overvoltage value, the reference voltage is consistent with the first current voltage output to the comparison subunit 222 by the voltage division filtering subunit 223; it can be understood that, when the reference voltage value is specifically set, due to practical application scenarios and device properties, etc., it is allowed that when the input power reaches the overvoltage value, the reference voltage has a certain error with the first current voltage output to the comparison subunit 222 by the voltage division filtering subunit 223.
The reference voltage output subunit 221 includes a first resistor R1 and a second resistor R2; wherein:
the first resistor R1 is connected between the comparison subunit 222 and the power supply; a second resistor R2 is connected between the comparator subunit 222 and ground.
The comparison subunit 222 includes a first comparator U1, a third resistor R3, and a fourth resistor R4; wherein:
the inverting input terminal of the first comparator U1 is connected with the output terminal of the voltage division filtering subunit 223; the non-inverting input terminal of the first comparator U1 is connected to the output terminal of the reference voltage output subunit 221, and the non-inverting input terminal of the first comparator U1 is further connected to the output terminal of the first comparator U1 through a third resistor R3; the output end of the first comparator U1 is connected with the power supply through a fourth resistor R4, and the output end of the first comparator U1 is the output end of the overvoltage judging unit.
The reference voltage output sub-unit 221 includes a first diode D1, a fifth resistor R5, and a sixth resistor R6; wherein:
the anode of the first diode D1 is connected to the output end of the sampling unit, the cathode of the first diode D1 is connected to the first end of the sixth resistor R6, the second end of the sixth resistor R6 is connected to the inverting input end of the first comparator U1, and the second end of the sixth resistor R6 is further grounded through the fifth resistor R5.
A non-inverting input terminal of the first comparator U1 receives a reference voltage, i.e., a first voltage threshold, of the power supply 400 divided by the first resistor R1 and the second resistor R2; the first detection signal output by the sampling unit 210 passes through the first diode D1, then is subjected to voltage division through the sixth resistor R6 and the fifth resistor R5, and the divided first detection signal is filtered by the first electrolytic capacitor C1 and then is output to the inverting input terminal of the first comparator U1;
when the detected phase voltage is not overvoltage, the voltage of the non-inverting input end of the first comparator U1 is smaller than that of the inverting input end, the first comparator U1 outputs a high level signal, when the detected phase voltage is overvoltage, the voltage of the non-inverting input end of the first comparator U1 is larger than that of the inverting input end, and the first comparator U1 outputs a low level signal.
The third resistor R3 is a positive feedback resistor of the first comparator U1, and when the first comparator U1 outputs a high level, the third resistor R3 is equivalently connected in parallel with the first resistor R1, so that the reference voltage of the non-inverting input end of the first comparator U1 is increased; when the first comparator U1 outputs a low level, the third resistor R3 is connected in parallel with the second resistor R2, so as to lower the reference voltage at the non-inverting input terminal of the first comparator U1, thereby forming a hysteresis comparator and preventing the oscillation of the threshold point.
It should be noted that, because the first voltage thresholds of the overvoltage determination units in the three sampling determination modules are identical, that is, voltages accessed by the non-inverting input terminals of the first comparators are identical, the non-inverting input terminals of the three first comparators may be connected in parallel.
Further, the undervoltage determining unit 230 includes a second comparator U2, a variable resistor RP1, a seventh resistor R7, an eighth resistor R8, and a ninth resistor R9; wherein:
the non-inverting input terminal of the second comparator U2 is connected to the output terminal of the sampling unit 210 through a seventh resistor R7, and the non-inverting input terminal of the second comparator U2 is further connected to the output terminal of the second comparator U2 through an eighth resistor R8;
the inverting input terminal of the second comparator U2 is connected to the power supply 400 through a ninth resistor R9, and the inverting input terminal of the second comparator U2 is also connected to ground through a variable resistor RP 1;
the output terminal of the second comparator U2 is the output terminal of the under-voltage determining unit 230.
The inverting input terminal of the second comparator U2 receives a reference voltage, i.e., a second voltage threshold, of the voltage of the power supply 400 divided by the ninth resistor R9 and the variable resistor RP 1; the first detection signal output by the sampling unit 210 is output to the non-inverting input terminal of the second comparator U2 through the seventh resistor R7;
when the detected phase voltage is not undervoltage or lack of phase, the voltage of the non-inverting input terminal of the second comparator U2 is greater than that of the inverting input terminal, the second comparator U2 outputs a high-level signal, and when the detected phase voltage is undervoltage or lack of phase, the voltage of the non-inverting input terminal of the second comparator U2 is less than that of the inverting input terminal, and the second comparator U2 outputs a low-level signal.
The eighth resistor R8 is a positive feedback resistor of the second comparator U2, and when the second comparator U2 outputs a high level, the non-inverting input terminal of the second comparator U2 superimposes a positive feedback voltage, so that the voltage of the non-inverting input terminal is increased; when the second comparator U2 outputs a low level, the non-inverting input terminal of the second comparator U2 superimposes a positive feedback voltage, so that the voltage at the non-inverting input terminal is reduced to form a hysteresis comparator, thereby preventing oscillation at a critical point.
It should be noted that, because the second voltage thresholds of the undervoltage determination units in the three sampling determination modules are consistent, that is, the voltages accessed by the inverting input terminals of the second comparators are consistent, the inverting input terminals of the three second comparators may be connected in parallel.
Further, the switch module 100 includes a relay K1, a contactor (not shown), a switch Q1, a second diode D2, a third diode D3, a tenth resistor R10, an eleventh resistor R11, and a twelfth resistor R12; wherein:
the control end of the switching tube Q1 is grounded through a tenth resistor R10, the control end of the switching tube Q1 is further connected with the first end of an eleventh resistor R11, the second end of the eleventh resistor R11 is connected with the anode of a second diode D2, the cathode of the second diode D2 is connected with the sampling judgment module 200, and the second end of the eleventh resistor R11 is further connected with the power supply 400 through a twelfth resistor R12;
the output end of the switching tube Q1 is grounded;
the input end of the switching tube Q1 is connected with the anode of a third diode D3, the cathode of a third diode D3 is connected with the power supply 400, the coil of the relay K1 is connected with the third diode D3 in parallel, and a group of normally open contacts of the relay K1 are connected in series in a coil loop H1 of the contactor;
the contactor comprises three groups of normally open contacts, and each group of normally open contacts are respectively connected between an input power supply and an external load.
It should be noted that the switch module 100 in this embodiment may include three second diodes D2, and the switch module 100 is connected to the three sampling determination modules 200 through the second diodes D2, respectively.
The switch tube Q1 in this embodiment is a triode, wherein the control terminal of the switch tube Q1 is the base of the triode, the input terminal of the switch tube Q1 is the collector of the triode, and the output terminal of the switch tube Q1 is the emitter of the triode. It is understood that the switching transistor Q1 may also be other switching elements, such as MOS transistors.
When no phase voltage has overvoltage, undervoltage or phase failure, all the first comparators U1 and the second comparator U2 output high levels, at the moment, the second diode D2 is cut off, the twelfth resistor R12 is a pull-up resistor, the control end of the switch tube Q1 receives the high levels, the switch tube Q1 is conducted, the coil of the relay K1 is electrified, the normally open contact of the relay K1 is closed, the coil of the contactor is electrified, the normally open contact of the contactor is closed, and the input power supply is connected with an external load.
When at least one phase voltage is overvoltage, undervoltage or open-phase, the corresponding first comparator U1 or the corresponding second comparator U2 outputs low level, at the moment, the second diode D2 is conducted, the control end of the switch tube Q1 receives the low level, the switch tube Q1 is turned off, the coil of the relay K1 is not electrified, the normally open contact of the relay K1 is disconnected, the coil of the contactor is not electrified, the normally open contact of the contactor is disconnected, and the input power supply is disconnected with an external load. It can be understood that three groups of normally open contacts of the contactor are respectively and correspondingly connected with one phase output of the input power supply and one phase input of the external load.
The third diode D3 is a protection diode of the relay K1, which bleeds off the high voltage that may be generated when the coil of the relay K1 is turned off.
Further, the overvoltage and undervoltage protection circuit further comprises a power supply 400, wherein the power supply 400 comprises a voltage reduction chip U3, a fourth diode D4, a second capacitor C2, a third electrolytic capacitor C3 and a fourth electrolytic capacitor C4; wherein:
the input end of the voltage reduction chip U3 is connected with the cathode of the fourth diode D4, the anode of the fourth diode D4 is connected with the output end of the voltage reduction rectifier subunit, the input end of the voltage reduction chip U3 is also connected with the anode of the third electrolytic capacitor C3, and the cathode of the third electrolytic capacitor C3 is grounded;
the output end of the voltage reduction chip U3 is the output end of the power supply 400, the output end of the voltage reduction chip U3 is further connected with the anode of a fourth electrolytic capacitor C4, the cathode of the fourth electrolytic capacitor C4 is grounded, and the output end of the voltage reduction chip U3 is further grounded through a second capacitor C2;
the ground terminal of the buck chip U3 is grounded.
It should be noted that the power supply 400 in this embodiment may include three fourth diodes D4, and the power supply 400 is connected to the three buck rectifier sub-units through the fourth diodes D4, respectively.
The rectified direct-current voltage output by the step-down rectifier subunit is filtered by a third electrolytic capacitor C3 through a fourth diode D4 and then input to a step-down chip U3, and the working voltage output by the step-down chip U3 is filtered by a fourth electrolytic capacitor C4 and a second capacitor C2 and then supplies power to other components.
The embodiment can reasonably detect the input power supply, judge the working state of the input power supply according to the detection result, and timely disconnect the load when the input power supply is in overvoltage, undervoltage or open-phase to protect the load.
Further, the sampling unit 210 includes a step-down rectifying sub-unit (not shown) and a sampling sub-unit (not shown); the input end of the step-down rectifier subunit is connected with the input power supply, the output end of the step-down rectifier subunit is connected with the input end of the sampling subunit, and the output end of the sampling subunit is the output end of the sampling unit 210.
The voltage reduction rectifier sub-unit is used for converting alternating current of an input power supply into direct current after reducing voltage;
and the sampling subunit is used for converting the direct current output by the voltage reduction rectifying subunit into a first detection signal.
Further, the step-down rectifying sub-unit comprises a transformer T1 and a rectifying bridge Z1; wherein:
a first input end of the transformer T1 is connected with a live wire of one phase of the input power supply, and a second input end of the transformer T1 is connected with a zero wire of the input power supply; a first output end of the transformer T1 is connected with a first alternating current end of the rectifier bridge Z1, and a second output end of the transformer T1 is connected with a second alternating current end of the rectifier bridge Z1; the positive pole of the rectifier bridge Z1 is connected with the input end of the sampling sub-unit, and the negative pole of the rectifier bridge Z1 is grounded.
The transformer T1 reduces the voltage of the AC input into the power supply; and the rectifier bridge Z1 is used for converting the alternating current after voltage reduction into direct current and outputting the direct current to the sampling subunit.
Further, the sampling sub-unit comprises a thirteenth resistor R13, a fourteenth resistor R14 and a fifth electrolytic capacitor C5; wherein:
a first end of the thirteenth resistor R13 is connected to the output end of the step-down rectifier unit, and a second end of the thirteenth resistor R13 is connected to the overvoltage judging unit 220 and the undervoltage judging unit 230, respectively; the second end of the thirteenth resistor R13 is further grounded through a fourteenth resistor R14, the second end of the thirteenth resistor R13 is further connected to the anode of the fifth electrolytic capacitor C5, and the cathode of the fifth electrolytic capacitor C5 is grounded.
The dc output from the step-down rectifier sub-unit is divided by the thirteenth resistor R13 and the fourteenth resistor R14 and then output to the overvoltage determining unit 220 and the undervoltage determining unit 230; the fifth electrolytic capacitor C5 is a filter capacitor.
This application still protects an crosses undervoltage protection device, should cross undervoltage protection device and include the casing and cross undervoltage protection circuit, should cross undervoltage protection circuit's structure and can refer to above-mentioned embodiment, no longer describe here. It should be noted that, since the overvoltage and undervoltage protection device of the embodiment adopts the technical scheme of the overvoltage and undervoltage protection circuit, the overvoltage and undervoltage protection device has all the beneficial effects of the overvoltage and undervoltage protection circuit.
It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or system. The term "comprising", without further limitation, means that the element so defined is not excluded from the group of processes, methods, articles, or systems that include the element. The above-mentioned serial numbers of the embodiments of the present application are merely for description and do not represent the merits of the embodiments.
The above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, it should 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; the modifications or substitutions do not cause the essence of the corresponding technical solutions to depart from the spirit and scope of the technical solutions of the embodiments of the present application, or to be directly or indirectly applied to other related technical fields, and are intended to be included within the scope of the present application.
Claims (10)
1. The overvoltage and undervoltage protection circuit is characterized by comprising N (N is more than or equal to 1 and N is an integer) sampling judgment modules and a switch module, wherein each sampling judgment module comprises a sampling unit, an overvoltage judgment unit and an undervoltage judgment unit; the sampling end of the sampling unit is connected with an input power supply, the output end of the sampling unit is respectively connected with the input end of the overvoltage judging unit and the input end of the undervoltage judging unit, the output end of the overvoltage judging unit and the output end of the undervoltage judging unit are respectively connected with the control end of the switch module, and the switch module is connected between the input power supply and an external load; wherein:
the sampling unit is used for detecting the voltage of the input power supply and respectively sending a first detection signal to the overvoltage judging unit and the undervoltage judging unit according to the detected voltage;
the overvoltage judging unit is used for judging whether overvoltage occurs according to the first detection signal and sending a first power-off signal to the switch module when the overvoltage occurs;
the undervoltage judging unit is used for judging whether undervoltage or open-phase occurs according to the first detection signal and sending a second power-off signal to the switch module when the undervoltage or open-phase occurs;
the switch module is used for disconnecting the input power supply from the external load when receiving the first power-off signal and/or the second power-off signal, and keeping the connection between the input power supply and the external load when not receiving the first power-off signal and not receiving the second power-off signal.
2. The under-voltage and over-voltage protection circuit of claim 1, wherein the over-voltage determining unit comprises a reference voltage output subunit, a comparing subunit and a voltage dividing and filtering subunit; wherein:
the input end of the voltage division filtering subunit is connected with the output end of the sampling unit, the output end of the voltage division filtering subunit is connected with the first input end of the comparison subunit, and the voltage division filtering subunit is used for performing voltage division filtering on the first detection signal and outputting a first current voltage to the comparison subunit;
the output end of the reference voltage output subunit is connected with the second input end of the comparison subunit, and the reference voltage output subunit is used for setting and providing reference voltage;
and the output end of the comparison subunit is connected with the control end of the switch module, and the comparison subunit is used for comparing the first current voltage with the reference voltage and sending the first power-off signal to the switch module when the first current voltage is greater than the reference voltage.
3. The under-voltage protection circuit of claim 2, wherein the reference voltage output subunit comprises a first resistor and a second resistor; wherein:
the first resistor is connected between the comparison subunit and a power supply; the second resistor is connected between the comparison subunit and ground.
4. The under-voltage protection circuit of claim 2, wherein the comparison subunit comprises a first comparator, a third resistor, and a fourth resistor; wherein:
the inverting input end of the first comparator is connected with the output end of the voltage division filtering subunit; the non-inverting input end of the first comparator is connected with the output end of the reference voltage output subunit, and the non-inverting input end of the first comparator is also connected with the output end of the first comparator through the third resistor; the output end of the first comparator is connected with the power supply through the fourth resistor, and the output end of the first comparator is the output end of the overvoltage judging unit.
5. The undervoltage protection circuit of claim 2, wherein the reference voltage output subunit comprises a first diode, a fifth resistor, and a sixth resistor; wherein:
the positive pole of the first diode is connected with the output end of the sampling unit, the negative pole of the first diode is connected with the first end of the sixth resistor, the second end of the sixth resistor is connected with the inverted input end of the first comparator, and the second end of the sixth resistor is grounded through the fifth resistor.
6. The under-voltage protection circuit of claim 1, wherein the under-voltage determining unit comprises a second comparator, a variable resistor, a seventh resistor, an eighth resistor, and a ninth resistor; wherein:
the non-inverting input end of the second comparator is connected with the output end of the sampling unit through the seventh resistor, and the non-inverting input end of the second comparator is also connected with the output end of the second comparator through the eighth resistor;
the inverting input end of the second comparator is connected with a power supply through the ninth resistor, and the inverting input end of the second comparator is grounded through the variable resistor;
the output end of the second comparator is the output end of the undervoltage judging unit.
7. The under-voltage and over-voltage protection circuit of claim 1, wherein N is equal to 3, the input power source is a three-phase power source, and each sampling judgment module is respectively connected between one phase output of the input power source and the switch module.
8. The overvoltage and undervoltage protection circuit of claim 7, wherein the switch module comprises a relay, a contactor, a switch tube, a second diode, a third diode, a tenth resistor, an eleventh resistor, and a twelfth resistor; wherein:
the control end of the switch tube is grounded through the tenth resistor, the control end of the switch tube is further connected with the first end of the eleventh resistor, the second end of the eleventh resistor is connected with the anode of the second diode, the cathode of the second diode is connected with the sampling judgment module, and the second end of the eleventh resistor is further connected with a power supply through the twelfth resistor;
the output end of the switch tube is grounded;
the input end of the switching tube is connected with the anode of the third diode, the cathode of the third diode is connected with the power supply, the coil of the relay is connected with the third diode in parallel, and a group of normally open contacts of the relay are connected in series in a coil loop of the contactor;
the contactor comprises three groups of normally open contacts, and each group of normally open contacts is connected between the input power supply and an external load respectively.
9. The over-voltage and under-voltage protection circuit according to any one of claims 1 to 8, further comprising a power supply, wherein the power supply comprises a buck chip, a fourth diode, a second capacitor, a third electrolytic capacitor and a fourth electrolytic capacitor; wherein:
the input end of the voltage reduction chip is connected with the cathode of the fourth diode, the anode of the fourth diode is connected with the output end of the voltage reduction rectifier unit, the input end of the voltage reduction chip is also connected with the anode of the third electrolytic capacitor, and the cathode of the third electrolytic capacitor is grounded;
the output end of the voltage reduction chip is the output end of the power supply, the output end of the voltage reduction chip is also connected with the anode of the fourth electrolytic capacitor, the cathode of the fourth electrolytic capacitor is grounded, and the output end of the voltage reduction chip is also grounded through the second capacitor;
and the grounding end of the voltage reduction chip is grounded.
10. An overvoltage and undervoltage protection device, comprising a housing and the overvoltage and undervoltage protection circuit according to any one of claims 1 to 9, wherein the overvoltage and undervoltage protection circuit is disposed in the housing.
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| CN202110890152.3A CN113488961A (en) | 2021-08-03 | 2021-08-03 | Over-voltage and under-voltage protection circuit and over-voltage and under-voltage protection device |
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| CN202110890152.3A CN113488961A (en) | 2021-08-03 | 2021-08-03 | Over-voltage and under-voltage protection circuit and over-voltage and under-voltage protection device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116819166A (en) * | 2023-08-31 | 2023-09-29 | 苏州贝克微电子股份有限公司 | High-voltage end undervoltage detection circuit |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN206099298U (en) * | 2016-10-19 | 2017-04-12 | 山东艾诺仪器有限公司 | Power supply monitoring circuit |
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2021
- 2021-08-03 CN CN202110890152.3A patent/CN113488961A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN206099298U (en) * | 2016-10-19 | 2017-04-12 | 山东艾诺仪器有限公司 | Power supply monitoring circuit |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116819166A (en) * | 2023-08-31 | 2023-09-29 | 苏州贝克微电子股份有限公司 | High-voltage end undervoltage detection circuit |
| CN116819166B (en) * | 2023-08-31 | 2023-11-03 | 苏州贝克微电子股份有限公司 | High-voltage end undervoltage detection circuit |
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