CN215870722U

CN215870722U - Protective circuit and circuit breaker of switching device

Info

Publication number: CN215870722U
Application number: CN202121206349.2U
Authority: CN
Inventors: 刘彬; 蒲韬; 朱可
Original assignee: Shanghai Chint Intelligent Technology Co Ltd
Current assignee: Shanghai Chint Intelligent Technology Co Ltd
Priority date: 2021-06-01
Filing date: 2021-06-01
Publication date: 2022-02-18
Anticipated expiration: 2031-06-01

Abstract

The utility model provides a switch electrical apparatus's protection circuit and circuit breaker, protection circuit include voltage detection control circuit and two at least controllable switch circuit, voltage detection control circuit can drive the controllable switch circuit disconnection that corresponds when mains voltage satisfies the threshold value, homoenergetic is to switch electrical apparatus's control circuit outage when arbitrary controllable switch circuit disconnection, two at least controllable switch circuit voltage threshold value when the disconnection different, the protection circuit is right the control circuit of circuit breaker carries out hierarchical protection, the protection circuit not only can reliably protect the circuit breaker, and the protection circuit can also reliably protect self moreover, prevents that protection circuit self from becoming invalid and other potential safety hazards that bring.

Description

Protective circuit and circuit breaker of switching device

Technical Field

The utility model relates to the field of low-voltage electrical appliances, in particular to a protection circuit and a circuit breaker of a switching electrical appliance.

Background

Intelligence will be a future trend, the industry of low-voltage electrical appliances is no exception, along with the construction of smart power grids and smart distribution areas in recent years, the intellectualization of circuit breaker products becomes a main requirement and a key technical index, in order to meet and realize the functions of intelligent thing connection, state full perception, automatic reclosing and the like, the working state and the mode of the circuit breaker are changed accordingly, if a power supply mode is changed from an original wire outlet end to a wire inlet end, namely no matter the circuit breaker body part is in a closing state or a switching-off state, a control circuit can still supply electricity from the front end of the circuit breaker body, so that the control circuit is in a normal working state.

Due to the change of the power supply mode of the circuit breaker, when a voltage fault occurs, such as an overvoltage fault or a lightning fault, the circuit breaker can be rapidly opened, although the load end can be cut off and disconnected to protect the power equipment and the circuit at the load end, the internal control circuit of the circuit breaker still bears the impact and the damage of the fault voltage, if the fault phenomenon exists for a long time or exists all the time, the circuit breaker can be greatly damaged or an accident is caused.

SUMMERY OF THE UTILITY MODEL

The utility model aims to overcome the defects of the prior art and provides a protection circuit of a switching device, which can protect a control circuit.

In order to achieve the purpose, the utility model adopts the following technical scheme:

the protection circuit of the switching device comprises a voltage detection control circuit and at least two controllable switching circuits, wherein the voltage detection control circuit can drive the corresponding controllable switching circuits to be disconnected when power supply voltage meets a threshold value, the control circuit of the switching device can be powered off when any one controllable switching circuit is disconnected, and the voltage threshold values of the at least two controllable switching circuits are different when the at least two controllable switching circuits are disconnected.

Preferably, one of the controllable switch circuits is a fuse circuit, the fuse circuit comprises a self-recovery fuse FU1 and a bleeder circuit, and the voltage detection control circuit can control the bleeder circuit to be switched on to fuse the self-recovery fuse FU 1.

Preferably, one of the controllable switch circuits is an electronic switch circuit, the electronic switch circuit includes an electronic switch K1, and the voltage detection control circuit can control the controllable switch element V2 to be turned on and the electronic switch K1 to be turned off.

Preferably, the at least two controllable switch circuits are an electronic switch circuit and a fusing circuit respectively, the electronic switch circuit and the fusing circuit are arranged at the rear end and the front end of the voltage detection control circuit respectively, and the disconnected voltage threshold of the electronic switch circuit is smaller than the disconnected voltage threshold of the fusing circuit.

Preferably, the bleeder circuit comprises a controllable switching element V1, and the voltage detection control circuit controls the controllable switching element V1 to conduct and perform current bleeder when the power supply voltage is higher than the fuse value.

Preferably, the voltage detection control circuit comprises comparators, the comparators are used for respectively controlling the on-off of the controllable switch circuits, and when the voltage detection circuit detects that the power supply voltage is greater than the off threshold of the controllable switch circuits, the voltage detection control circuit controls the corresponding controllable switch circuits to be switched off.

Preferably, the voltage detection circuit comprises a U1, a comparator U1, a resistor R, a capacitor C and a voltage regulator tube VZ, the comparator U1 and the comparator U1 are respectively used for controlling a controllable switch element V of a fusing circuit and a controllable switch element V of an electronic switch circuit, the resistor R and the voltage regulator tube VZ are connected in series and then output a voltage reference source Ref to the reverse input end of the comparator U1, the resistor R and the resistor R are connected in series between an L line and an N line, the capacitor C is connected in parallel at two ends of the resistor R and the resistor R, one end of the resistor R is connected between the resistor R and the resistor R, the other end of the resistor R is respectively connected with the equidirectional input end of the comparator U1, the output end of the comparator U1 is respectively connected with the control end of the controllable switch element V, one end of the resistor R and one end of the resistor R, the other end of the resistor R is connected with the equidirectional input end of the comparator U1, the other end of the resistor R12 is grounded, one end of the resistor R9 is connected between the resistor R7 and the resistor R11, the other end of the resistor R9 is connected with the equidirectional input end of the comparator U1B, and the output end of the comparator U1B is connected with the control end of the controllable switch element V1.

The protection circuit of the switching apparatus can cut off the power supply of the control circuit when serious voltage faults occur, can effectively prevent the control circuit from being damaged and potential safety hazards caused by the voltage faults even if the control circuit is connected to the wire inlet end of the switching apparatus, is safer in power utilization, has high application value and market potential, and is more reliable in protection function by realizing graded protection through at least two controllable switching circuits.

The utility model also provides a circuit breaker which can break a main circuit of the circuit breaker when a power supply circuit reaches a voltage threshold value of the voltage protection of the circuit breaker, and the circuit breaker comprises a control circuit and a protection circuit of the switching device, wherein the protection circuit is connected between a wire inlet end and the control circuit. The voltage threshold for protecting the power supply circuit and the voltage threshold for protecting the circuit breaker are different protection thresholds.

Drawings

Fig. 1 is a schematic structural diagram of a protection circuit of a switching device according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a protection circuit of a switching device according to an embodiment of the present invention.

Detailed Description

The following describes a specific embodiment of the protection circuit of the switching device according to the present invention with reference to the embodiments shown in fig. 1 to 2. The protection circuit of the switching apparatus of the present invention is not limited to the description of the following embodiments.

As shown in fig. 1-2, the protection circuit of the switching device of the present invention includes a voltage detection control circuit and at least two controllable switching circuits, the voltage detection control circuit can drive the corresponding controllable switching circuit to be turned off when the power supply voltage meets a threshold, when any one of the controllable switching circuits is turned off, the control circuit of the switching device can be powered off, and the voltage thresholds of the at least two controllable switching circuits are different when the at least two controllable switching circuits are turned off.

The protection circuit of the switching apparatus can cut off the power supply of the control circuit when voltage faults occur, can effectively prevent the control circuit from being damaged and potential safety hazards caused by the voltage faults even if the control circuit is connected to the wire inlet end of the switching apparatus, is safer in power utilization, has high application value and market potential, and is more reliable in protection function by realizing graded protection through at least two controllable switching circuits.

The switching device of the embodiment is a circuit breaker, the protection circuit is arranged at the front end of the control circuit and is positioned between the incoming line end of the circuit breaker and the control circuit, and the circuit breaker can break a main circuit of the circuit breaker when a power circuit reaches a voltage threshold value for protecting the voltage of the circuit breaker, which is the existing function of the circuit breaker. In the figure, a main function circuit forms a control circuit of the circuit breaker, the main function circuit can be a single chip microcomputer or a microprocessor MCU, a protection circuit comprises a voltage detection control circuit and at least two controllable switch circuits, the number of the controllable switch circuits in the figure is two, the at least two controllable switch circuits are respectively an electronic switch circuit and a fusing circuit, the fusing circuit and the electronic switch circuit are respectively arranged at the front end and the rear end of the voltage detection control circuit,

the main function circuit sequentially passes through the electronic switch circuit, the voltage detection control circuit and the fusing circuit to obtain electricity from a main loop power supply of the circuit breaker body, namely, from one side of a wire inlet end of the circuit breaker body, when the voltage of the main loop power supply of the circuit breaker is normal or power-off, the electronic switch circuit and the fusing circuit are respectively in a switch-on state, and the function of the control circuit is normally operated;

when faults such as overvoltage occur and the voltage reaches the voltage threshold value of the voltage protection of the circuit breaker, the main function circuit drives the actuating mechanism to trip the circuit breaker to protect a load connected to the circuit breaker;

when the voltage of the main loop power supply reaches the voltage threshold value of the electronic switch circuit, the voltage detection control circuit drives the electronic switch circuit to be switched off and stops supplying power to the main function circuit;

when the voltage of the main loop power supply reaches a voltage threshold value of the disconnection of the fusing circuit, the voltage detection control circuit drives the fusing circuit to be disconnected, and the voltage detection control circuit is powered off;

the voltage threshold of the breaker voltage protection < the voltage threshold of the electronic switch circuit disconnection < the voltage threshold of the fuse circuit disconnection. The voltage threshold of the breaker voltage protection is generally set according to application or reference standards, the voltage threshold of the electronic switch circuit disconnection is generally set to the maximum voltage value of the circuit disconnection capable of working normally, and the voltage threshold of the fuse circuit disconnection is generally set to the limit voltage value of the breaker capable of bearing without damage.

This embodiment passes through electronic switch circuit and fusing circuit hierarchical protection, and fusing circuit and electronic switch circuit are respectively at voltage detection control circuit's front end and rear end, can protect main function circuit when electronic switch circuit breaks off, but voltage detection control circuit still can normally work, and can drive electronic switch circuit recovery operating condition fast after the trouble is relieved, when voltage further rose, voltage detection control circuit control fusing circuit disconnection, protect voltage detection control circuit. It is understood that the two controllable switch circuits may adopt other operating principles, or both the two controllable switch circuits adopt electronic switch circuits, or both the two controllable switch circuits adopt fuse circuits, and all fall within the protection scope of the present invention.

As shown in fig. 2, one of the controllable switch circuits is a fuse circuit, the fuse circuit includes a self-recovery fuse FU1 and a bleeder circuit, and the voltage detection control circuit can control the bleeder circuit to be turned on, so that the self-recovery fuse FU1 fuses. The bleeder circuit comprises a controllable switch element V1, and when the power supply voltage is higher than the fusing value, the voltage detection control circuit controls the controllable switch element V1 to be conducted to perform current bleeder.

Specifically, the fuse circuit comprises a self-recovery fuse FU1 and a controllable switch element V1 connected with the self-recovery fuse FU1, and when a fault occurs, the voltage detection control circuit can control the controllable switch element V1 to be switched on, so that the current in the self-recovery fuse FU1 is increased, and the self-recovery fuse FU1 is actively switched off; after the fault disappears, the self-recovery fuse FU1 can automatically recover to work. Specifically, the fuse circuit comprises a self-recovery fuse FU1 and a rectifying device D1 which are connected with an L line in series, a controllable switch element V1 and a resistor R4 which are connected between output ends of the rectifying device D1, a control electrode of the controllable switch element V1 is respectively connected with the resistor R10 and a voltage detection control circuit, the controllable switch element V1 is pulled down through the resistor R10 to be grounded, the controllable switch element V1 is controlled to be switched on and off by the voltage detection control circuit, and the rectifying device D1 converts power supply voltage from alternating current to direct current voltage.

When the fuse circuit needs to be disconnected in case of a fault, namely, when the voltage threshold value of the disconnection of the fuse circuit is met, the voltage detection control circuit controls the controllable switch element V1 to be switched on, the controllable switch element V1 is used for switching on the resistor R4 to form a leakage current, the value of the leakage current is large, the current value of the self-recovery fuse wire FU1 is increased to enable the self-recovery fuse wire FU1 to be heated and switched off, and then the control circuit and the power supply are completely cut off. When the fault is relieved, the self-recovery fuse FU1 is conducted again after the temperature is reduced to supply power for the voltage detection control circuit and the main function circuit, and the voltage detection control circuit can detect the voltage again. The controllable switching element V1 of this embodiment is a thyristor, and may be replaced by the MOS transistor, the triode, and other elements, which all belong to the protection scope of the present invention. The self-recovery fuse FU1 is more serious than the electronic switch circuit aiming at the fault voltage range, after the serious overvoltage fault occurs, the device which bears the thermal effect or the transient breakdown damage caused by the overvoltage in the electronic switch circuit can be recovered through the inherent characteristic delay recovery of the self-recovery fuse FU 1.

As shown in fig. 2, one of the controllable switch circuits is an electronic switch circuit, which includes an electronic switch K1, and the voltage detection control circuit can control the controllable switch element V2 to be turned on, so that the electronic switch K1 is turned off.

Specifically, the electronic switch circuit includes electronic switch K1 to and be used for controlling the controllable switch element V2 of electronic switch K1's actuation, electronic switch K1 is the relay, and when breaking down, voltage detection control circuit can control controllable switch element V2 and switch on, makes electronic switch K1 actuation, and normally closed contact disconnection, the back that the trouble disappears, and electronic switch K1's normally closed contact resumes to switch on. Specifically, the electronic switch circuit comprises an electronic switch K1, the electronic switch K1 comprises a normally closed contact connected in series with an L line, two ends of an electromagnetic mechanism of the electronic switch K1 are respectively connected with a resistor R3 and a resistor R8, two ends of a resistor R8 are connected in parallel with a controllable switch element V2, a control electrode of the controllable switch element V2 is connected with a voltage detection control circuit, and the voltage detection control circuit controls the on-off of the controllable switch element V2.

When the electronic switching circuit needs to be disconnected in case of a fault, namely, when the voltage threshold value of the electronic switching circuit is met, the voltage detection control circuit controls the controllable switching element V2 to be switched on, the controllable switching element V2 is used for short-circuiting the resistor R8, the current of the electromagnetic mechanism passing through the electronic switch K1 is increased, the electromagnetic mechanism attracts the normally closed contact to be disconnected, and then the electronic switching circuit is disconnected. When the fault is relieved, the voltage detection control circuit controls the controllable switch element V2 to be switched off, the electromagnetic mechanism is released, the normally closed contact is closed again, and the electronic switch circuit is switched on again to supply power for the main function circuit. The electronic switch K1 is driven by a circuit and is completely controlled by a voltage detection circuit, and when a fault occurs, the voltage and a main function circuit can be quickly disconnected; after the fault is relieved, the power supply of the main functional circuit can be quickly switched on.

It will be appreciated that the electronic switch circuit may also employ other components in place of the electronic switch K1, such as a contactor, etc., and the electronic switch K1 is not limited to normally closed contacts. In addition, the MOS transistor V2 is a controllable switching element, and may be replaced by a thyristor, a triode, or other elements, which all belong to the protection scope of the present invention.

As shown in fig. 2, the voltage detection control circuit includes comparators, and the comparators respectively control on/off of the controllable switch circuits, and when the voltage detection circuit detects that the power supply voltage is greater than the off threshold of the controllable switch circuit, the voltage detection control circuit controls the corresponding controllable switch circuit to be off.

Specifically, the voltage detection control circuit comprises two comparators, wherein the two comparators are respectively used for controlling a controllable switch element V1 of the fusing circuit and a controllable switch element V2 of the electronic switch circuit, the two comparators are respectively used for comparing the sampling voltage with a voltage threshold value of disconnection of the electronic switch circuit and a voltage threshold value of disconnection of the fusing circuit, and the two comparators are used for turning on the corresponding controllable switch element V1 and the controllable switch element V2 when the voltage signals meet the threshold values;

the voltage detection control circuit comprises a comparator U1A and a comparator U1A which form the two comparators, a resistor R A, a capacitor C A and a voltage regulator VZ A, wherein the resistor R A and the voltage regulator VZ A are connected in series for outputting a voltage reference source Ref A and are connected with the reverse input end of the comparator U1A, the resistor R A and the resistor R A are connected between an L line and an N line in series, the capacitor C A is connected between the two ends of the resistor R A and the resistor R A in parallel for forming a voltage division circuit, one end of the resistor R A is connected between the resistor R A and the resistor R A, the other end of the resistor R A is respectively connected with the same-direction input end of the comparator U1A, the output end of the comparator U1A and the other end of the controllable switch element V A are respectively connected with the input end of the resistor R A, and the other end of the comparator U A, and the output end of the resistor R A are respectively connected with the other end of the resistor R A, the other end of the resistor R12 is pulled down to be grounded, one end of the resistor R9 is connected between the resistor R7 and the resistor R11, the other end of the resistor R9 is connected with the equidirectional input end of the comparator U1B, and the output end of the comparator U1B is connected with the controllable switch element V1 as the gate of the control end.

The protection circuit of the switching device is suitable for protecting the control circuit connected to the wire inlet end of the switching device, and can effectively protect the switching device body and the control circuit when serious voltage faults occur. The switch electric appliance comprises a wire inlet end, a wire outlet end, a contact mechanism connected between the wire inlet end and the wire outlet end, and a control circuit connected with the wire inlet end. The control circuit obtains a power supply from an incoming line end, when the circuit has a fault, the control circuit comprises one or more of undervoltage, overvoltage, short circuit, electric leakage and the like, the control circuit triggers the moving contact and the fixed contact of the contact mechanism to be separated through the actuating mechanism, or the protection mechanism of the switching device can trigger the moving contact and the fixed contact of the contact mechanism to be separated, so that the switching device is tripped and tripped to realize the protection of equipment at a load end, the protection mechanism of the switching device can comprise one or more of an undervoltage tripper, an overvoltage tripper, an overload protection mechanism, a short-circuit protection mechanism or an electric leakage tripper, but the protection mechanism of the switching device can not realize the protection of the control circuit, the protection circuit of the utility model is used for realizing the protection of the control circuit, the graded protection is realized through at least two controllable switching circuits, when the serious voltage fault occurs, the switching device can not only disconnect the load end in time, and the power supply of the control circuit can be cut off, so that the damage and potential safety hazard caused by voltage faults to the switching device can be effectively prevented, and the power utilization is safer and more reliable.

The hysteresis comparison circuit is composed of a comparator U1A, the comparator U1A judges whether to turn on or off the electronic switch circuit according to a maximum threshold value VHth and a minimum threshold value VLth, the on-off threshold voltage of the electronic switch circuit is respectively the minimum threshold value VLth and the maximum threshold value VHth, the comparator U1A does not act when the sampling voltage is between the maximum threshold value VHth and the minimum threshold value VLth, the sampling voltage of the embodiment is the voltage division value between resistors R2 and R7, and the electronic switch circuit is prevented from being frequently switched around the voltage threshold value; when the sampling voltage is higher than the maximum threshold value VHth, the comparator U1A outputs low level to control the controllable switch element V2 to be switched off, and then the electronic switch circuit is switched off; when the sampled voltage is lower than the minimum threshold value VLth, the comparator U1A outputs a high level to control the controllable switching element V2 to be turned on and turn on the electronic switching circuit. It should be understood that the comparator U1A may also be determined according to a certain voltage threshold corresponding to the electronic switching circuit, and although it may be frequently switched around the threshold, it is within the scope of the present invention.

In step S4, the comparator U1B determines whether to disconnect the fuse circuit according to a voltage threshold corresponding to the fuse circuit, and when the sampling voltage is higher than the voltage reference source Ref1, the voltage is sampled by the present embodiment, that is, the divided voltage value between the resistor R7 and the resistor R11, and the comparator U1B outputs a high level to turn on the controllable switch element V1, so that the current in the loop where the self-recovery fuse FU1 is located is increased, and the fuse circuit is disconnected through the self-recovery fuse FU 1; after the self-recovery fuse recovery FU1, if the power supply voltage is normal, the operation resumes from step S1.

The embodiment controls the on-off of the electronic switch circuit and the fusing circuit by obtaining sampling voltages from different voltage dividing resistors and comparing the sampling voltages with a voltage reference source Ref 1. Of course, the on/off of the electronic switch circuit and the fuse circuit can also be controlled by comparing the same sampling voltage with two different voltage reference sources (i.e. different threshold values).

The utility model also provides a protection method of the switching device, when the voltage detection control circuit detects that the power supply voltage reaches the voltage threshold value of the electronic switching circuit, the electronic switching circuit is driven to be switched off; and when the power supply voltage reaches a voltage threshold value for breaking the fusing circuit, the fusing circuit is driven to break, and the voltage threshold value of the voltage protection of the circuit breaker < the voltage threshold value for breaking the electronic switch circuit < the voltage threshold value for breaking the fusing circuit. The fuse circuit comprises a self-recovery fuse wire, and after the fuse circuit is disconnected and the fault is relieved, the self-recovery fuse wire can be conducted again to supply power for the voltage detection control circuit and the control circuit; after the electronic switch circuit is switched off and the sampling voltage is lower than the voltage threshold value of the electronic switch circuit, the voltage detection control circuit drives the electronic switch circuit to be switched on.

The foregoing is a more detailed description of the utility model in connection with specific preferred embodiments and it is not intended that the utility model be limited to these specific details. For those skilled in the art to which the utility model pertains, several simple deductions or substitutions can be made without departing from the spirit of the utility model, and all shall be considered as belonging to the protection scope of the utility model.

Claims

1. A protection circuit of a switching device is characterized in that: the voltage detection control circuit can drive the corresponding controllable switch circuit to be disconnected when the power supply voltage meets a threshold value, the control circuit of the switching device can be powered off when any controllable switch circuit is disconnected, and the voltage threshold values of the at least two controllable switch circuits are different when the at least two controllable switch circuits are disconnected.

2. The protection circuit of switching apparatus according to claim 1, wherein: one of them controllable switch circuit is the fusing circuit, and the fusing circuit includes self-resuming fuse FU1 and bleeder circuit, and voltage detection control circuit can control the bleeder circuit and switch on, makes self-resuming fuse FU1 fusing.

3. The protection circuit of switching apparatus according to claim 1, wherein: one of the controllable switch circuits is an electronic switch circuit which comprises an electronic switch K1, and the voltage detection control circuit can control the controllable switch element V2 to be switched on so as to switch off the electronic switch K1.

4. A protection circuit of a switching apparatus according to any one of claims 1 to 3, characterized in that: the at least two controllable switch circuits are respectively an electronic switch circuit and a fusing circuit, the electronic switch circuit and the fusing circuit are respectively arranged at the rear end and the front end of the voltage detection control circuit, and the disconnected voltage threshold of the electronic switch circuit is smaller than that of the fusing circuit.

5. The protection circuit of a switching apparatus according to claim 2, wherein: the bleeder circuit comprises a controllable switch element V1, and when the power supply voltage is higher than the fusing value, the voltage detection control circuit controls the controllable switch element V1 to be conducted to perform current bleeder.

6. The protection circuit of switching apparatus according to claim 1, wherein: the voltage detection control circuit comprises comparators, the on-off of the controllable switch circuits are respectively controlled through the comparators, and when the voltage detection control circuit detects that the power supply voltage is larger than the off threshold of the controllable switch circuits, the corresponding controllable switch circuits are controlled to be off.

7. The protection circuit of switching apparatus according to claim 1, wherein: the voltage detection control circuit comprises a U1, a comparator U1, a resistor R, a capacitor C and a voltage regulator tube VZ, wherein the comparator U1 and the comparator U1 are respectively used for controlling a controllable switch element V of a fusing circuit and a controllable switch element V of an electronic switch circuit, the resistor R and the voltage regulator tube VZ are connected in series and then output a voltage reference source Ref to the reverse input end of the comparator U1, the resistor R and the resistor R are connected in series between an L line and an N line, the capacitor C is connected in parallel at two ends of the resistor R and the resistor R, one end of the resistor R is connected between the resistor R and the resistor R, the other end of the resistor R is respectively connected with the equidirectional input end of the comparator U1, the output end of the comparator U1 is respectively connected with the control end of the controllable switch element V, one end of the resistor R and one end of the resistor R, the other end of the resistor R is connected with the equidirectional input end of the comparator U1, the other end of the resistor R12 is grounded, one end of the resistor R9 is connected between the resistor R7 and the resistor R11, the other end of the resistor R9 is connected with the equidirectional input end of the comparator U1B, and the output end of the comparator U1B is connected with the control end of the controllable switch element V1.

8. The utility model provides a circuit breaker, can break circuit breaker major loop when power supply circuit reaches the voltage threshold value of circuit breaker voltage protection which characterized in that: protection circuit comprising a control circuit and a switching device according to any one of claims 1-7 connected between the incoming line terminal and the control circuit.