Circuit breaker protection circuit

Abstract

The utility model provides a circuit breaker protection circuit. The circuit breaker protection circuit comprises a control circuit, a magnetic latching relay, a relay driving circuit, a release, a release trigger circuit, a signal receiving circuit and a power supply circuit. The control circuit is electrically connected with the signal receiving circuit, the relay driving circuit and the release trigger circuit, the output end of the relay driving circuit is electrically connected with the magnetic latching relay, the output end of the release trigger circuit is electrically connected with the release, and the power supply circuit supplies power to the control circuit, the release trigger circuit and the relay driving circuit. Wherein the magnetic latching relay and the release both act on the target moving contact, so as to control the connection and disconnection of the corresponding power supply loop by controlling the connection relationship between the target moving contact and the static contact corresponding to the target moving contact. The whole system is low in cost and simple to control; both automatic opening and manual opening can be realized; and the method has the processing capability of processing different fault processing efficiency requirements.

Description

Technical Field

[0001] The utility model relates to the technical field of circuit breakers, in particular to a circuit breaker protection circuit. Background Art

[0002] During use, the circuit breaker may encounter various circuit faults, such as overload fault, short circuit fault, ground fault, overvoltage fault, undervoltage fault, arc flashover fault, etc. When a fault occurs, the circuit breaker needs to take corresponding protection measures.

[0003] In some circuit breaker usage scenarios, circuit breakers usually use thermal magnetic mechanisms for opening protection, and the reclosing after protection is usually operated by a motor. The entire system is costly and complex to control. Utility Model Content

[0004] In view of the deficiencies in the prior art, the utility model provides a circuit breaker protection circuit.

[0005] In one embodiment, the utility model provides a circuit breaker protection circuit, the circuit breaker protection circuit comprising:

[0006] Control circuit, magnetic latching relay, relay driving circuit, trip unit, trip unit triggering circuit, signal receiving circuit and power supply circuit;

[0007] The first input end of the control circuit is electrically connected to the output end of the signal receiving circuit, the first driving end of the control circuit is electrically connected to the input end of the relay driving circuit, the output end of the relay driving circuit is electrically connected to the magnetic latching relay, the second driving end of the control circuit is electrically connected to the input end of the release trigger circuit, the output end of the release trigger circuit is electrically connected to the release, and the output end of the power supply circuit is electrically connected to the power supply end of the control circuit, the power supply end of the release trigger circuit and the power supply end of the relay driving circuit respectively;

[0008] Among them, the magnetic latching relay and the release both act on the target moving contact to control the on-off of the corresponding power supply circuit by controlling the connection relationship between the target moving contact and the static contact corresponding to the target moving contact.

[0009] In one embodiment, the relay driving circuit includes a first half-bridge driving chip, a second half-bridge driving chip, a first MOS transistor, a second MOS transistor, a third MOS transistor, and a fourth MOS transistor;

[0010] The input end of the first half-bridge driver chip is electrically connected to the first closing driver end of the control circuit, the first output end of the first half-bridge driver chip is electrically connected to the gate of the first MOS tube, and the second output end of the first half-bridge driver chip is electrically connected to the gate of the third MOS tube;

[0011] The input end of the second half-bridge driver chip is electrically connected to the first opening gate driver end of the control circuit, the first output end of the second half-bridge driver chip is electrically connected to the gate of the second MOS tube, and the second output end of the second half-bridge driver chip is electrically connected to the gate of the fourth MOS tube;

[0012] The first source and drain of the first MOS tube and the first source and drain of the second MOS tube are electrically connected to the output end of the power supply circuit respectively, the second source and drain of the first MOS tube and the first source and drain of the third MOS tube are electrically connected to the first end of the magnetic holding relay respectively, the second source and drain of the second MOS tube and the first source and drain of the fourth MOS tube are electrically connected to the second end of the magnetic holding relay respectively, and the second source and drain of the third MOS tube and the source and drain of the fourth MOS tube are grounded respectively.

[0013] In one embodiment, the release trigger circuit includes a fifth MOS tube and a freewheeling diode;

[0014] The gate of the fifth MOS tube is electrically connected to the second driving end of the control circuit, the cathode of the freewheeling diode is electrically connected to the output end of the power supply circuit and the first end of the release, the anode of the freewheeling diode is electrically connected to the first source and drain of the fifth MOS tube and the second end of the release, and the second source and drain of the fifth MOS tube is grounded.

[0015] In one embodiment, the power supply circuit includes a first buck circuit and a second buck circuit;

[0016] The input end of the first step-down circuit is electrically connected to the input end of the power supply circuit, the output end of the first step-down circuit is electrically connected to the input end of the second step-down circuit, the power end of the relay drive circuit and the power end of the release trigger circuit respectively, and the output end of the second step-down circuit is electrically connected to the power end of the control circuit.

[0017] In one embodiment, the power circuit includes an isolated DC-DC power supply and a third step-down circuit;

[0018] The input end of the isolated DC-DC power supply is used to connect to an external power supply, the output end of the isolated DC-DC power supply is electrically connected to the input end of the third step-down circuit, the power end of the relay drive circuit and the power end of the release trigger circuit respectively, and the output end of the third step-down circuit is electrically connected to the power end of the control circuit.

[0019] In one embodiment, the signal receiving circuit includes a first photocoupler;

[0020] The positive pole of the input terminal of the first photocoupler is electrically connected to the corresponding positive signal input terminal, the negative pole of the input terminal of the first photocoupler is electrically connected to the corresponding negative signal input terminal, the positive pole of the output terminal of the first photocoupler is electrically connected to the output terminal of the power supply circuit, and the negative pole of the output terminal of the first photocoupler is electrically connected to the first input terminal of the control circuit.

[0021] In one embodiment, the signal receiving circuit includes a second photocoupler and a third photocoupler;

[0022] The positive pole of the input end of the second photocoupler and the negative pole of the input end of the third photocoupler are electrically connected to the corresponding positive signal input terminal respectively, the negative pole of the input end of the second photocoupler and the positive pole of the input end of the third photocoupler are electrically connected to the corresponding negative signal input terminal respectively, the positive pole of the output end of the second photocoupler and the positive pole of the output end of the third photocoupler are electrically connected to the output end of the power supply circuit respectively, the negative pole of the output end of the second photocoupler is electrically connected to the first closing input end of the control circuit, and the negative pole of the output end of the third photocoupler is electrically connected to the first opening input end of the control circuit.

[0023] In one embodiment, the circuit breaker protection circuit further comprises:

[0024] At least one of a current detection circuit, a voltage detection circuit, and a temperature detection circuit;

[0025] The input end of the current detection circuit is electrically connected to the power supply circuit, and the output end of the current detection circuit is electrically connected to the second input end of the control circuit;

[0026] The input end of the voltage detection circuit is electrically connected to the power supply circuit, and the output end of the voltage detection circuit is electrically connected to the third input end of the control circuit;

[0027] The output end of the temperature detection circuit is electrically connected to the fourth input end of the control circuit.

[0028] In one embodiment, the current sensing circuit includes a shunt and an operational amplifier;

[0029] The shunt is connected in series in the power supply circuit, the first end of the shunt is electrically connected to the in-phase input end of the operational amplifier, the second end of the shunt is electrically connected to the inverting input end of the operational amplifier, and the output end of the operational amplifier is electrically connected to the second input end of the control circuit.

[0030] In one embodiment, the voltage detection circuit includes a first voltage-dividing resistor and a voltage sampling resistor, and the temperature detection circuit includes a second voltage-dividing resistor and a temperature-sensitive resistor;

[0031] The first end of the first voltage-dividing resistor is electrically connected to the power supply circuit, the second end of the first voltage-dividing resistor is electrically connected to the first end of the voltage sampling resistor and the third input end of the control circuit respectively, and the second end of the voltage sampling resistor is grounded;

[0032] The first end of the second voltage-dividing resistor is electrically connected to the output end of the power supply circuit, the second end of the second voltage-dividing resistor is electrically connected to the first end of the temperature-sensitive resistor and the fourth input end of the control circuit respectively, and the second end of the temperature-sensitive resistor is grounded.

[0033] Through the above-mentioned circuit breaker protection circuit, a tripper and a magnetic latching relay are set to realize opening protection and reclosing after protection. The whole system has low cost and simple control; secondly, since both the tripper and the magnetic latching relay are provided, the tripper and the magnetic latching relay can be driven by the tripper trigger circuit and the relay drive circuit to realize automatic opening, and manual opening can also be realized by directly manually operating the tripper; in addition, the opening speed of the tripper is usually greater than that of the magnetic latching relay, so the tripper and the magnetic latching relay can simultaneously have the processing capabilities to handle different fault handling efficiency requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0035] Figure 1 This is a schematic diagram of the structure of a circuit breaker protection circuit in one embodiment of the utility model;

[0036] Figure 2 This is a schematic diagram of the structure of a relay drive circuit in one embodiment of the utility model;

[0037] Figure 3 This is a schematic diagram of the structure of a release trigger circuit in one embodiment of the utility model;

[0038] Figure 4 This is a schematic diagram of the structure of a first step-down circuit in one embodiment of the utility model;

[0039] Figure 5 This is a schematic diagram of the structure of a second step-down circuit in one embodiment of the utility model;

[0040] Figure 6 This is a connection diagram of an isolated DC-DC power supply in one embodiment of the utility model;

[0041] Figure 7 This is a schematic diagram of the structure of a signal receiving circuit in one embodiment of the utility model;

[0042] Figure 8 This is a schematic diagram of the structure of a signal receiving circuit in another embodiment of the utility model;

[0043] Fig. 9 This is a schematic diagram of the structure of a current detection circuit in one embodiment of the utility model;

[0044] Fig.10 This is a schematic diagram of the structure of a voltage detection circuit in one embodiment of the utility model;

[0045] Fig.11 The figure is a schematic diagram of the structure of a temperature detection circuit in one embodiment of the utility model. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0047] In the description of the present utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, which are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. In the present application, the word "exemplary" is used to mean "used as an example, illustration or description". Any embodiment described as "exemplary" in the present application is not necessarily interpreted as being more preferred or more advantageous than other embodiments. In order to enable any person skilled in the art to implement and use the utility model, the following description is given. In the following description, details are listed for the purpose of explanation. It should be understood that one of ordinary skill in the art can recognize that the utility model can be implemented without using these specific details. In other examples, well-known structures and processes will not be elaborated in detail to avoid unnecessary details that make the description of the utility model obscure. Therefore, the utility model is not intended to be limited to the embodiments shown, but is consistent with the widest range of principles and features disclosed in this application.

[0048] First, as Figure 1As shown, in one embodiment, the utility model provides a circuit breaker protection circuit, which includes a control circuit, a magnetic latching relay, a relay drive circuit, a release, a release trigger circuit, a signal receiving circuit and a power supply circuit.

[0049] Among them, the trip unit is a protective device whose main function is to quickly cut off the circuit when the circuit is overloaded, short-circuited or other faults occur to protect the safety of electrical equipment and personnel. The trip unit's action speed is usually at the millisecond level, and it can respond very quickly.

[0050] Among them, relays are usually used to monitor parameters or conditions in circuits and trigger actions when specific events or conditions are detected. The speed of the relay's action can vary depending on the design and application needs, and is usually also in the millisecond level, but may be slightly slower than the trip unit because the response time of the relay may be affected by its working principle and construction. The magnetic latching relay is a special type of relay that has the ability to maintain its own state. Usually, the relay is closed when the activation current passes through, but once the activation current stops, the relay returns to the open circuit state of the initial state. The magnetic latching relay is closed when the activation current passes through, and is kept closed by its own internal magnetic mechanism. Even if the activation current stops, it will remain closed until it receives a reverse deactivation signal.

[0051] Among them, the signal receiving circuit is used to receive corresponding control signals, including an opening control signal and a closing control signal, and send the received control signal to the control circuit so that the control circuit completes the corresponding control operation.

[0052] The circuit breaker involved in the circuit breaker protection circuit in this embodiment can be used in a communication base station. In this scenario, the control signal received by the signal receiving circuit is usually a remote signal. For example, a remote communication module can be used to convert the received radio into a corresponding control signal, thereby sending the corresponding control signal to the signal receiving circuit; of course, the signal receiving circuit itself can also directly integrate the corresponding remote communication module.

[0053] Among them, the control circuit can adopt integrated devices such as MCU.

[0054] like Figure 1As shown, the first input end of the control circuit is electrically connected to the output end of the signal receiving circuit, the first driving end of the control circuit is electrically connected to the input end of the relay driving circuit, the output end of the relay driving circuit is electrically connected to the magnetic latching relay, the second driving end of the control circuit is electrically connected to the input end of the release trigger circuit, the output end of the release trigger circuit is electrically connected to the release, and the output end of the power supply circuit is electrically connected to the power supply end of the control circuit, the power supply end of the release trigger circuit and the power supply end of the relay driving circuit respectively;

[0055] Among them, the magnetic latching relay and the release both act on the target moving contact to control the on-off of the corresponding power supply circuit by controlling the connection relationship between the target moving contact and the static contact corresponding to the target moving contact.

[0056] Among them, Figure 1 In the figure, the power supply circuit refers to the circuit corresponding to the positive power supply input terminal DC+_IN, the negative power supply input terminal DC-_IN, the positive power supply output terminal DC+_OUT and the negative power supply output terminal DC+_OUT.

[0057] Among them, under normal circumstances, the working state of the release is in the opening state. When the signal receiving circuit receives the closing control signal, the control circuit drives the magnetic latching relay through the relay driving circuit to perform the closing operation, so that the power supply circuit is turned on; when the signal receiving circuit receives the opening control signal or does not receive the closing control signal, the control circuit drives the magnetic latching relay through the relay driving circuit to perform the opening operation, so that the power supply circuit is disconnected. Further, when the power supply circuit is turned on because the signal receiving circuit receives the closing control signal, if a circuit fault occurs, the control circuit can selectively drive the magnetic latching relay to open or the release to trip through the relay driving circuit or the release trigger circuit to achieve automatic opening; in addition, the operator can also directly manually operate the release to achieve manual opening.

[0058] Through the above-mentioned circuit breaker protection circuit, a tripper and a magnetic latching relay are set to realize opening protection and reclosing after protection. The whole system has low cost and simple control; secondly, since both the tripper and the magnetic latching relay are provided, the tripper and the magnetic latching relay can be driven by the tripper trigger circuit and the relay drive circuit to realize automatic opening, and manual opening can also be realized by directly manually operating the tripper; in addition, the opening speed of the tripper is usually greater than that of the magnetic latching relay, so the tripper and the magnetic latching relay can simultaneously have the processing capabilities to handle different fault handling efficiency requirements.

[0059] like Figure 2As shown, in one embodiment, the relay driving circuit includes a first half-bridge driving chip U2, a second half-bridge driving chip U3, a first MOS transistor Q1, a second MOS transistor Q2, a third MOS transistor Q3, and a fourth MOS transistor Q4.

[0060] As mentioned above, the magnetic latching relay can open and close the switch, and the magnetic latching relay can act on the permanent magnet mechanically connected to the target moving contact by generating magnetic fields of different polarities, so that the permanent magnet drives the target moving contact to move in opposite directions, and finally achieves opening and closing. To meet this demand, the two half-bridge driver chips can realize the existence of currents in opposite directions on the magnetic latching relay, so that the magnetic latching relay generates magnetic fields of different polarities.

[0061] like Figure 2 As shown, the input terminals IN and SD of the first half-bridge driver chip U2 are electrically connected to the first closing driver terminal of the control circuit to receive corresponding closing driver signals ON_Relay and ON_SD, the first output terminal HO of the first half-bridge driver chip U2 is electrically connected to the gate of the first MOS tube Q1 through the resistor R6, and the second output terminal LO of the first half-bridge driver chip U2 is electrically connected to the gate of the third MOS tube Q3 through the resistor R8.

[0062] like Figure 2 As shown, the input terminals IN and SD of the second half-bridge driver chip U3 are electrically connected to the first opening gate driver terminal of the control circuit to access the corresponding opening gate driver signals OFF_Relay and OFF_SD, the first output terminal HO of the second half-bridge driver chip U3 is electrically connected to the gate of the second MOS tube Q2 through the resistor R7, and the second output terminal LO of the second half-bridge driver chip U3 is electrically connected to the gate of the fourth MOS tube Q4 through the resistor R9.

[0063] like Figure 2 As shown, the first source and drain of the first MOS transistor Q1 and the first source and drain of the second MOS transistor Q2 are respectively electrically connected to the output end of the power supply circuit to access the +12V working voltage, the second source and drain of the first MOS transistor Q1 and the first source and drain of the third MOS transistor Q3 are respectively electrically connected to the first end of the magnetic latching relay, the second source and drain of the second MOS transistor Q2 and the first source and drain of the fourth MOS transistor Q4 are respectively electrically connected to the second end of the magnetic latching relay, and the second source and drain of the third MOS transistor Q3 and the source and drain of the fourth MOS transistor Q4 are respectively grounded. It should be understood that one of the first source and drain and the second source and drain described in this embodiment is the source of the MOS transistor, and the other is the drain, which can be determined according to the type of the MOS transistor. For example, when the first source and drain of the first MOS transistor Q1 is the source, the second source and drain of the first MOS transistor Q1 is the drain.

[0064] As an example, when the control circuit drives the first MOS tube Q1 and the fourth MOS tube Q4 to be turned on through the first half-bridge driver chip U2 and the second half-bridge driver chip U3 respectively, the +12V working voltage connected passes through the first MOS tube Q1, the magnetic latching relay, the fourth MOS tube Q4 and then to the ground, forming a current in a first direction; when the control circuit drives the second MOS tube Q2 and the third MOS tube Q3 to be turned on through the first half-bridge driver chip U2 and the second half-bridge driver chip U3 respectively, the +12V working voltage connected passes through the second MOS tube Q2, the magnetic latching relay, the third MOS tube Q3 and then to the ground, forming a current in a second direction opposite to the first direction. The currents in the two directions cause the magnetic latching relay to generate magnetic fields of different polarities to achieve opening and closing.

[0065] like Figure 2 As shown, the relay driving circuit also includes a first bootstrap diode D1, a first bootstrap capacitor C5, a second bootstrap diode D2 and a second bootstrap capacitor C6, the first bootstrap diode D1 is electrically connected between the power supply terminal VCC and the floating power supply terminal VB of the first half-bridge driving chip U2, the first bootstrap capacitor C5 is electrically connected between the power supply terminal VCC and the power return terminal Vs of the first half-bridge driving chip U2, the second bootstrap diode D2 is electrically connected between the power supply terminal VCC and the floating power supply terminal VB of the second half-bridge driving chip U3, and the second bootstrap capacitor C6 is electrically connected between the power supply terminal VCC and the power return terminal Vs of the second half-bridge driving chip U3. The first bootstrap diode D1 and the first bootstrap capacitor C5 constitute a first bootstrap circuit, and the second bootstrap diode D2 and the second bootstrap capacitor C6 constitute a second bootstrap circuit, which play the role of preventing backflow and boosting.

[0066] like Figure 3 As shown, in one embodiment, the release trigger circuit includes a fifth MOS tube Q5 and a freewheeling diode D3.

[0067] Among them, the gate of the fifth MOS tube Q5 is electrically connected to the second driving end of the control circuit to access the driving signal Trippers_Sing, the cathode of the freewheeling diode D3 is electrically connected to the output end of the power supply circuit and the first end of the tripper respectively to access the working voltage (such as +12V working voltage), the anode of the freewheeling diode D3 is electrically connected to the first source and drain of the fifth MOS tube Q5 and the second end of the tripper respectively, and the second source and drain of the fifth MOS tube Q5 is grounded.

[0068] Among them, when the control circuit drives the fifth MOS tube Q5 to turn on, the connected working voltage passes through the release and the fifth MOS tube Q5 and then to the ground, forming a current, causing the release to generate a magnetic field and complete the corresponding tripping operation. When the control circuit stops driving the fifth MOS tube Q5, the fifth MOS tube Q5 is disconnected, and the current on the release is discharged through the freewheeling diode D3 to complete the freewheeling discharge.

[0069] Among them, Figure 3 As shown, the release trigger circuit also includes a voltage-dividing resistor R15 and a voltage-dividing resistor R25. The voltage-dividing resistor R15 is electrically connected between the second driving end of the control circuit and the gate of the fifth MOS tube Q5. The voltage-dividing resistor R25 is electrically connected between the gate of the fifth MOS tube Q5 and the ground terminal. The voltage-dividing resistor R15 and the voltage-dividing resistor R25 output the divided voltage to the gate of the fifth MOS tube Q5 to achieve reliable gate drive.

[0070] In one embodiment, the power supply circuit includes a first buck circuit and a second buck circuit.

[0071] The input end of the first step-down circuit is electrically connected to the input end of the power supply circuit, the output end of the first step-down circuit is electrically connected to the input end of the second step-down circuit, the power end of the relay drive circuit and the power end of the release trigger circuit respectively, and the output end of the second step-down circuit is electrically connected to the power end of the control circuit.

[0072] Among them, the working voltages required by the control circuit, the relay drive circuit and the release trigger circuit are different, so the power supply circuit needs to provide power supply voltages of different amplitudes. Specifically, the amplitude of the working voltage required by the relay drive circuit and the release trigger circuit is higher than the amplitude of the working voltage required by the control circuit, so the voltage obtained by the first step-down circuit is directly output to the power supply end of the relay drive circuit and the power supply end of the release trigger circuit, and the second step-down circuit needs to further perform a second step-down on the voltage output by the first step-down circuit, and then output the obtained voltage to the power supply end of the control circuit.

[0073] Among them, as an alternative example, Figure 4 As shown, the first buck circuit includes a first buck chip U4, a feedback resistor R10, a feedback resistor R15, an input filter capacitor C8, an output filter capacitor C9, and a filter inductor L1. The input filter capacitor C8 is electrically connected between the input terminal VIN and the ground terminal GND of the first buck chip U4, the filter inductor L1 is electrically connected between the output terminal SW of the first buck chip U4 and the input terminal of the second buck circuit, and the output filter capacitor C9 is electrically connected between the input terminal and the ground terminal GND of the second buck circuit. The input filter capacitor C8, the filter inductor L1, and the output filter capacitor C9 constitute a filter circuit, which plays a role in filtering and noise reduction. The feedback resistor R10 and the feedback resistor R15 are connected in series and electrically connected between the input terminal and the ground terminal GND of the second buck circuit. The feedback resistor R10 and the feedback resistor R15 are used to feedback the output voltage division to the feedback terminal FB of the first buck chip U4. In addition, Figure 4 The diode D3 and capacitor C7 are the basic structure of the circuit and will not be described in detail here.

[0074] Among them, Figure 5 As shown, the second buck circuit includes a second buck chip U6, an input filter capacitor C18, an output filter capacitor C20, a filter inductor L2, a feedback resistor R19, a feedback resistor R23, a bootstrap capacitor C15 and a bootstrap resistor R18. The input filter capacitor C18 is electrically connected between the input terminal VIN and the ground terminal GND of the second buck chip U6, the filter inductor L2 is electrically connected between the output terminal SW of the first buck chip U4 and the power supply terminal of the control circuit, the output filter capacitor C20 is electrically connected between the power supply terminal and the ground terminal GND of the control circuit, and the input filter capacitor C18, the filter inductor L2 and the output filter capacitor C20 constitute a filter circuit, which plays a role in filtering and noise reduction. The feedback resistor R19 and the feedback resistor R23 are connected in series and are electrically connected between the power supply terminal and the ground terminal GND of the control circuit. The feedback resistor R19 and the feedback resistor R23 are used to feedback the output voltage division to the feedback terminal FB of the second buck chip U6. The bootstrap capacitor C15 and the bootstrap resistor R18 are connected in series and electrically connected between the bootstrap terminal of the second buck chip U6 and the filter inductor L2. Figure 5 The resistor R20 and the capacitor NC are the basic structure of the circuit and will not be described in detail here.

[0075] In one embodiment, the power circuit includes an isolated DC-DC power supply and a third step-down circuit.

[0076] like Figure 6 As shown, the input end of the isolated DC-DC power supply is used to connect to an external power supply (Power_IN+ and Power_IN-), and the output end of the isolated DC-DC power supply is electrically connected to the input end of the third step-down circuit, the power end of the relay drive circuit, and the power end of the release trigger circuit, respectively, to output an operating voltage (such as a +12V operating voltage), and the output end of the third step-down circuit is electrically connected to the power end of the control circuit.

[0077] The structure of the third step-down circuit may be the same as the second step-down circuit in the above embodiment. For details, please refer to the above embodiment and will not be described in detail here.

[0078] Among them, the above embodiments have mentioned that the power supply circuit can be powered directly from the input end of the power supply loop, so there is no need for isolation. In this embodiment, the power supply circuit is powered from an external power supply, so an isolated DC-DC power supply needs to be added to achieve electrical isolation.

[0079] like Figure 7 As shown, in one embodiment, the signal receiving circuit includes a first photocoupler U5.

[0080] Among them, the positive pole of the input end of the first photocoupler U5 is electrically connected to the corresponding positive signal input terminal ON / OFF_Trigger, the negative pole of the input end of the first photocoupler U5 is electrically connected to the corresponding negative signal input terminal Power_IN-, the positive pole of the output end of the first photocoupler U5 is electrically connected to the output end of the power supply circuit to access the working voltage (such as the working voltage of +3V3), and the negative pole of the output end of the first photocoupler U5 is electrically connected to the first input end of the control circuit to output the control signal ON / OFF_Control.

[0081] Among them, when the positive signal input terminal ON / OFF_Trigger inputs a high level, the first photocoupler U5 is turned on, and the control signal ON / OFF_Control received at the first input end of the control circuit is a high level. When the positive signal input terminal ON / OFF_Trigger inputs a low level, the first photocoupler U5 is cut off, and the control signal ON / OFF_Control received at the first input end of the control circuit is a low level, so that the control circuit determines the specific meaning of the control signal according to the level received at the first input end.

[0082] Among them, combined Figure 7 and Figure 6 As shown, when an external power supply is used, the negative signal input terminal and the negative external power supply input terminal can be shared.

[0083] Among them, electrical isolation is required when an external power supply is used. Similarly, the control signal received by the signal receiving circuit also comes from the outside, so electrical isolation is also required.

[0084] like Figure 8 As shown, in one embodiment, the signal receiving circuit includes a second photocoupler U8 and a third photocoupler U7.

[0085] Among them, the positive pole of the input end of the second photocoupler U8 and the negative pole of the input end of the third photocoupler U7 are respectively electrically connected to the corresponding positive signal input terminal SW_Control+, the negative pole of the input end of the second photocoupler U8 and the positive pole of the input end of the third photocoupler U7 are respectively electrically connected to the corresponding negative signal input terminal SW_Control-, the positive pole of the output end of the second photocoupler U8 and the positive pole of the output end of the third photocoupler U7 are respectively electrically connected to the output end of the power supply circuit to connect to the working voltage (such as the working voltage of +3V3), the negative pole of the output end of the second photocoupler U8 is electrically connected to the first closing input end of the control circuit to output the closing control signal ON_Control+, and the negative pole of the output end of the third photocoupler U7 is electrically connected to the first opening input end of the control circuit to output the opening control signal ON_Control-.

[0086] Among them, when the positive signal input terminal SW_Control+ outputs a high level and the negative signal input terminal SW_Control- outputs a low level, the second photocoupler U8 is turned on, and the first closing input terminal of the control circuit receives a high-level closing control signal ON_Control+; when the positive signal input terminal SW_Control+ outputs a low level and the negative signal input terminal SW_Control- outputs a high level, the third photocoupler U7 is turned on, and the first opening input terminal of the control circuit receives a high-level opening control signal ON_Control-. In addition, Figure 8 The resistors R25, R26, R27 and R28 are the basic structure of the circuit and will not be described in detail here.

[0087] Further reading Figure 1 As shown, in one embodiment, the circuit breaker protection circuit further includes a current detection circuit, a voltage detection circuit and a temperature detection circuit.

[0088] Among them, the input end of the current detection circuit is electrically connected to the power supply circuit, and the output end of the current detection circuit is electrically connected to the second input end of the control circuit; the input end of the voltage detection circuit is electrically connected to the power supply circuit, and the output end of the voltage detection circuit is electrically connected to the third input end of the control circuit; the output end of the temperature detection circuit is electrically connected to the fourth input end of the control circuit.

[0089] In other embodiments, the circuit breaker protection circuit may also include only one or two of the current detection circuit, the voltage detection circuit and the temperature detection circuit.

[0090] The current detection circuit can detect the current in the power supply circuit in real time and feed it back to the control circuit so that the control circuit can determine whether the power supply circuit is short-circuited or overloaded.

[0091] The voltage detection circuit can detect the voltage input to the power supply circuit in real time and feed it back to the control circuit so that the control circuit can determine whether the power supply circuit is over-voltage or under-voltage.

[0092] The temperature detection circuit can detect the temperature of the power supply circuit in real time and feed it back to the control circuit so that the control circuit can determine whether the power supply circuit is over-temperature.

[0093] like Fig. 9 As shown, in one embodiment, the current sensing circuit includes a shunt and an operational amplifier U1A.

[0094] Among them, the shunt is connected in series in the power supply circuit, the first end of the shunt is electrically connected to the non-inverting input end of the operational amplifier U1A, the second end of the shunt is electrically connected to the inverting input end of the operational amplifier U1A, and the output end of the operational amplifier U1A is electrically connected to the second input end of the control circuit to output the current detection signal ADC_I.

[0095] The shunt outputs the voltages at both ends to the two input ends of the operational amplifier U1A respectively, so that the operational amplifier U1A determines the difference in terminal voltages of the shunt, and the control circuit determines the current flowing through the shunt according to the voltage difference and the resistance of the shunt itself.

[0096] in, Fig. 9 The resistor R2, the resistor R3, the resistor R4, the resistor R5, the capacitor C1 and the capacitor C2 are the basic structure of the circuit and will not be described in detail here.

[0097] like Fig.10 As shown, in one embodiment, the voltage detection circuit includes a first voltage dividing resistor (including a resistor R11 and a resistor R12) and a voltage sampling resistor R16. Fig.11 As shown, the temperature detection circuit includes a second voltage-dividing resistor R22 and a temperature-sensitive resistor R24.

[0098] The first end of the resistor R11 is electrically connected to the power supply circuit to access the 48VDC voltage, the second end of the resistor R11 is electrically connected to the first end of the resistor R12, the second end of the resistor R12 is electrically connected to the first end of the voltage sampling resistor R16 and the third input end of the control circuit respectively to output the voltage detection signal DC_IN, and the second end of the voltage sampling resistor R16 is grounded. In addition, Fig.10 The resistor R13 and the capacitor C12 are the basic structure of the circuit and will not be described in detail here.

[0099] The first end of the second voltage-dividing resistor R22 is electrically connected to the output end of the power supply circuit to access the +3V3 working voltage, the second end of the second voltage-dividing resistor R22 is electrically connected to the first end of the temperature-sensitive resistor R24 ​​and the fourth input end of the control circuit to output the temperature detection signal Temperature_V, and the second end of the temperature-sensitive resistor R24 ​​is grounded. In addition, Fig.11 The capacitor C23 in the circuit is the basic structure of the circuit and will not be described in detail here.

[0100] In a second aspect, in one embodiment, the utility model provides a circuit breaker protection method, which is applied to the circuit breaker protection circuit in any of the above embodiments; the circuit breaker protection method includes the following steps performed by the control circuit:

[0101] Acquiring a control signal received by a signal receiving circuit;

[0102] Wherein, taking the above-mentioned signal receiving circuit using one photocoupler as an example, the corresponding control signal includes a high level representing closing and a low level representing opening; taking the above-mentioned signal receiving circuit using two photocouplers as an example, the corresponding control signal includes a high level representing closing and a high level representing opening;

[0103] According to the control signal, a corresponding drive signal is sent to the relay drive circuit, so that the relay drive circuit drives the magnetic latching relay to perform a closing operation or an opening operation, thereby making the target moving contact and the corresponding static contact contact or separate;

[0104] If the control signal indicates closing, the magnetic latching relay is driven to close; if the control signal indicates opening, the magnetic latching relay is driven to open;

[0105] When the target moving contact and the corresponding static contact are in contact, if a power supply circuit fails, a corresponding drive signal is sent to the relay drive circuit or the release trigger circuit, so that the relay drive circuit drives the magnetic holding relay to perform an opening operation or the release trigger circuit drives the release to perform a tripping operation, thereby separating the target moving contact and the corresponding static contact.

[0106] When a power supply circuit fails, since both the magnetic latching relay and the releaser can be opened, one of the magnetic latching relay and the releaser can be selectively driven to open the circuit.

[0107] Through the above-mentioned circuit breaker protection method, a tripper and a magnetic latching relay are set to realize opening protection and reclosing after protection, and the whole system has low cost and simple control; secondly, since both the tripper and the magnetic latching relay are provided, the tripper and the magnetic latching relay can be driven by the tripper trigger circuit and the relay drive circuit to realize automatic opening, and manual opening can also be realized by directly manually operating the tripper; in addition, the opening speed of the tripper is usually greater than that of the magnetic latching relay, so the tripper and the magnetic latching relay can simultaneously have the processing capabilities to handle different fault handling efficiency requirements.

[0108] In one embodiment, if a power supply circuit fails, a corresponding drive signal is sent to a relay drive circuit or a release trigger circuit, so that the relay drive circuit drives the magnetic latching relay to perform an opening operation or the release trigger circuit drives the release to perform a tripping operation, thereby separating the target moving contact and the corresponding static contact, including:

[0109] If a short circuit occurs in the power supply circuit, a corresponding driving signal is sent to the release trigger circuit, so that the release trigger circuit drives the release to perform a tripping operation, thereby separating the target moving contact and the corresponding static contact;

[0110] If an overload fault, overvoltage fault, undervoltage fault or overtemperature fault occurs in the power supply circuit, a corresponding drive signal is sent to the relay drive circuit so that the relay drive circuit drives the magnetic latching relay to perform a trip operation, thereby separating the target moving contact and the corresponding static contact.

[0111] Among them, short-circuit faults can be understood as instantaneous faults, while overload faults, overvoltage faults, undervoltage faults, and overtemperature faults can be understood as long-delay faults. Instantaneous faults are relatively urgent. Therefore, in order to improve the performance of fault resolution, when a short-circuit fault occurs, the circuit breaker is opened through the release to meet its time requirements. For other faults, a magnetic latching relay is used for opening.

[0112] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the detailed description of other embodiments above, and will not be repeated here.

[0113] A circuit breaker protection circuit provided by the utility model is introduced in detail above. The principle and implementation mode of the utility model are described in detail in this article by using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the utility model. At the same time, for technicians in this field, according to the idea of ​​the utility model, there will be changes in the specific implementation mode and application scope. In summary, the content of this specification should not be understood as limiting the utility model.

[0114] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A circuit breaker protection circuit, characterized in that: The circuit breaker protection circuit comprises: Control circuit, magnetic latching relay, relay driving circuit, trip unit, trip unit triggering circuit, signal receiving circuit and power supply circuit; The first input end of the control circuit is electrically connected to the output end of the signal receiving circuit, the first driving end of the control circuit is electrically connected to the input end of the relay driving circuit, the output end of the relay driving circuit is electrically connected to the magnetic latching relay, the second driving end of the control circuit is electrically connected to the input end of the release trigger circuit, the output end of the release trigger circuit is electrically connected to the release, and the output end of the power supply circuit is electrically connected to the power supply end of the control circuit, the power supply end of the release trigger circuit and the power supply end of the relay driving circuit respectively; Wherein, the magnetic latching relay and the release both act on the target moving contact to control the on-off of the corresponding power supply circuit by controlling the connection relationship between the target moving contact and the static contact corresponding to the target moving contact.

2. The circuit breaker protection circuit according to claim 1, characterized in that: The relay driving circuit includes a first half-bridge driving chip, a second half-bridge driving chip, a first MOS tube, a second MOS tube, a third MOS tube, and a fourth MOS tube; The input end of the first half-bridge driver chip is electrically connected to the first closing driver end of the control circuit, the first output end of the first half-bridge driver chip is electrically connected to the gate of the first MOS transistor, and the second output end of the first half-bridge driver chip is electrically connected to the gate of the third MOS transistor; The input end of the second half-bridge driver chip is electrically connected to the first opening gate driver end of the control circuit, the first output end of the second half-bridge driver chip is electrically connected to the gate of the second MOS transistor, and the second output end of the second half-bridge driver chip is electrically connected to the gate of the fourth MOS transistor; The first source and drain of the first MOS tube and the first source and drain of the second MOS tube are electrically connected to the output end of the power supply circuit respectively, the second source and drain of the first MOS tube and the first source and drain of the third MOS tube are electrically connected to the first end of the magnetic holding relay respectively, the second source and drain of the second MOS tube and the first source and drain of the fourth MOS tube are electrically connected to the second end of the magnetic holding relay respectively, and the second source and drain of the third MOS tube and the source and drain of the fourth MOS tube are grounded respectively.

3. The circuit breaker protection circuit according to claim 1, characterized in that: The release trigger circuit includes a fifth MOS tube and a freewheeling diode; The gate of the fifth MOS tube is electrically connected to the second driving end of the control circuit, the cathode of the freewheeling diode is electrically connected to the output end of the power supply circuit and the first end of the release, the anode of the freewheeling diode is electrically connected to the first source and drain of the fifth MOS tube and the second end of the release, and the second source and drain of the fifth MOS tube is grounded.

4. The circuit breaker protection circuit according to claim 1, characterized in that: The power supply circuit includes a first step-down circuit and a second step-down circuit; The input end of the first step-down circuit is electrically connected to the input end of the power supply circuit, the output end of the first step-down circuit is electrically connected to the input end of the second step-down circuit, the power end of the relay drive circuit and the power end of the release trigger circuit respectively, and the output end of the second step-down circuit is electrically connected to the power end of the control circuit.

5. The circuit breaker protection circuit according to claim 1, characterized in that: The power supply circuit includes an isolated DC-DC power supply and a third step-down circuit; The input end of the isolated DC-DC power supply is used to connect to an external power supply, the output end of the isolated DC-DC power supply is electrically connected to the input end of the third step-down circuit, the power end of the relay drive circuit and the power end of the release trigger circuit respectively, and the output end of the third step-down circuit is electrically connected to the power end of the control circuit.

6. The circuit breaker protection circuit according to claim 1, characterized in that: The signal receiving circuit includes a first photocoupler; The positive pole of the input terminal of the first photocoupler is electrically connected to the corresponding positive signal input terminal, the negative pole of the input terminal of the first photocoupler is electrically connected to the corresponding negative signal input terminal, the positive pole of the output terminal of the first photocoupler is electrically connected to the output terminal of the power supply circuit, and the negative pole of the output terminal of the first photocoupler is electrically connected to the first input terminal of the control circuit.

7. The circuit breaker protection circuit according to claim 1, characterized in that: The signal receiving circuit includes a second photoelectric coupler and a third photoelectric coupler; The positive pole of the input end of the second photocoupler and the negative pole of the input end of the third photocoupler are electrically connected to the corresponding positive signal input terminals respectively, the negative pole of the input end of the second photocoupler and the positive pole of the input end of the third photocoupler are electrically connected to the corresponding negative signal input terminals respectively, the positive pole of the output end of the second photocoupler and the positive pole of the output end of the third photocoupler are electrically connected to the output end of the power supply circuit respectively, the negative pole of the output end of the second photocoupler is electrically connected to the first closing input end of the control circuit, and the negative pole of the output end of the third photocoupler is electrically connected to the first opening input end of the control circuit.

8. The circuit breaker protection circuit according to any one of claims 1 to 7, characterized in that: The circuit breaker protection circuit also includes: At least one of a current detection circuit, a voltage detection circuit, and a temperature detection circuit; The input end of the current detection circuit is electrically connected to the power supply circuit, and the output end of the current detection circuit is electrically connected to the second input end of the control circuit; The input end of the voltage detection circuit is electrically connected to the power supply circuit, and the output end of the voltage detection circuit is electrically connected to the third input end of the control circuit; The output end of the temperature detection circuit is electrically connected to the fourth input end of the control circuit.

9. The circuit breaker protection circuit according to claim 8, characterized in that: The current detection circuit includes a shunt and an operational amplifier; The shunt is connected in series in the power supply circuit, the first end of the shunt is electrically connected to the non-inverting input end of the operational amplifier, the second end of the shunt is electrically connected to the inverting input end of the operational amplifier, and the output end of the operational amplifier is electrically connected to the second input end of the control circuit.

10. The circuit breaker protection circuit according to claim 8, characterized in that: The voltage detection circuit includes a first voltage-dividing resistor and a voltage sampling resistor, and the temperature detection circuit includes a second voltage-dividing resistor and a temperature-sensitive resistor; The first end of the first voltage-dividing resistor is electrically connected to the power supply circuit, the second end of the first voltage-dividing resistor is electrically connected to the first end of the voltage sampling resistor and the third input end of the control circuit respectively, and the second end of the voltage sampling resistor is grounded; The first end of the second voltage-dividing resistor is electrically connected to the output end of the power supply circuit, the second end of the second voltage-dividing resistor is electrically connected to the first end of the temperature-sensitive resistor and the fourth input end of the control circuit respectively, and the second end of the temperature-sensitive resistor is grounded.

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