CN220821408U

CN220821408U - Control circuit of low-voltage direct-current contactor and low-voltage direct-current contactor

Info

Publication number: CN220821408U
Application number: CN202322265563.0U
Authority: CN
Inventors: 葛淼; 胡德辉
Original assignee: Delixi Electric Co Ltd
Current assignee: Delixi Electric Co Ltd
Priority date: 2023-08-22
Filing date: 2023-08-22
Publication date: 2024-04-19
Anticipated expiration: 2033-08-22

Abstract

The application provides a control circuit of a low-voltage direct current contactor and the low-voltage direct current contactor, wherein the control circuit comprises: the device comprises a coil control unit, a power supply access unit and a coil action unit. The first end of the power supply access unit is electrically connected with the first input end of the control unit. The second end of the coil control unit is electrically connected with the first end of the coil action unit, the first end of the coil action unit is electrically connected with the first end of the coil, the second end of the coil is electrically connected with the third end of the coil action unit, the third end of the coil action unit is electrically connected with the fourth control end of the coil control unit, the third end of the coil control unit is electrically connected with the second end of the coil action unit, and the second end of the coil action unit is electrically connected with the first end of the coil. Therefore, when the direct current input power supply voltage values are different, the stable actuation or release of the coil is controlled, the power consumption of the contactor is reduced, and hidden hazards such as fire disaster are avoided.

Description

Control circuit of low-voltage direct-current contactor and low-voltage direct-current contactor

Technical Field

The application relates to the field of contactors, in particular to a control circuit of a low-voltage direct-current contactor and the low-voltage direct-current contactor.

Background

At present, the low-voltage direct current contactor is widely applied to aspects such as power utilization, power distribution control and the like. The low-voltage direct-current contactor usually uses a magnetic field generated by a coil to attract the low-voltage direct-current contactor, and releases the low-voltage direct-current contactor when the magnetic field is not present. However, when the dc voltage is unstable, the current flowing through the coil of the conventional low-voltage dc contactor is unstable, so that the magnetic field which can be generated by the coil is unstable, and the conventional low-voltage dc contactor is unstable in actuation or longer in release time, thereby causing the problems of overload, short circuit or fire disaster of the circuit.

Disclosure of utility model

The application provides a control circuit of a low-voltage direct current contactor and the low-voltage direct current contactor, which can enable the low-voltage direct current contactor to be stably attracted or quickly released when input voltage is unstable.

In a first aspect, the present application provides a control circuit for a low voltage dc contactor, comprising: coil control unit, power access unit and coil action unit.

The first end of the power supply access unit is electrically connected with the first input end of the control unit. The second end of the coil control unit is electrically connected with the first end of the coil action unit, the first end of the coil action unit is electrically connected with the first end of the coil, the second end of the coil is electrically connected with the third end of the coil action unit, the third end of the coil action unit is electrically connected with the fourth control end of the coil control unit, the third end of the coil control unit is electrically connected with the second end of the coil action unit, and the second end of the coil action unit is electrically connected with the first end of the coil. The first channel is formed among the second end of the coil control unit, the first end of the coil action unit, the first end of the coil, the second end of the coil, the third end of the coil action unit and the fourth control end of the coil control unit. A second channel is formed among the third end of the coil control unit, the second end of the coil action unit, the first end of the coil, the second end of the coil, the third end of the coil action unit and the fourth control end of the coil control unit.

The power supply access unit is used for accessing the direct current input power supply voltage and sending a first voltage to the coil control unit, wherein the first voltage is used for representing the change condition of the direct current input power supply voltage.

And the coil control unit is used for controlling the first channel and the second channel to be closed when the first voltage indicates that the direct current input power supply voltage is smaller than the first pull-in voltage so as to release the coil.

The coil control unit is further used for sending a pulse signal to the coil action unit when the first voltage indicates that the direct current input power supply voltage is greater than or equal to the first pull-in voltage. When the level of the pulse signal is high, the first channel is controlled to be conducted and the second channel is controlled to be closed, so that the coil is attracted. When the level of the pulse signal is low, the second channel is controlled to be conducted and the first channel is controlled to be closed so as to enable the coil to be attracted.

The control circuit of the low-voltage direct current contactor provided by the application is connected with the direct current input power supply voltage and sends the first voltage to the coil control unit, wherein the first voltage is used for representing the change condition of the direct current input power supply voltage. When the first voltage represents that the direct current input power supply voltage is smaller than the first pull-in voltage, the first channel and the second channel are controlled to be closed, so that the coil is released. When the first voltage represents that the direct current input power supply voltage is greater than or equal to the first pull-in voltage, a pulse signal is sent to the coil action unit. When the level of the pulse signal is high, the first channel is controlled to be conducted and the second channel is controlled to be closed, so that the coil is attracted. When the level of the pulse signal is low, the second channel is controlled to be conducted and the first channel is controlled to be closed so as to enable the coil to be attracted. Therefore, when the direct current input power supply is larger than the minimum pull-in voltage, the control circuit of the low-voltage direct current contactor and the low-voltage direct current contactor comprising the control circuit can enable the coil of the contactor to be stably pulled in through controlling the conduction of the first channel or the second channel, and when the input power supply voltage is smaller than the minimum pull-in voltage, the coil of the contactor is controlled to be released, so that the power consumption is reduced, the purpose of saving energy is achieved, and potential safety hazards such as fire disaster are avoided.

In one possible design, the coil action unit includes: the coil release circuit comprises a power supply voltage reducing circuit, a coil pull-in circuit and a coil release circuit.

The first end of the power supply access unit is electrically connected with the first input end of the coil control unit, the second end of the coil control unit is electrically connected with the first end of the coil pull-in circuit, the second end of the coil pull-in circuit is electrically connected with the first end of the coil, the second end of the coil is electrically connected with the first end of the coil release circuit, the second end of the coil release circuit is electrically connected with the fourth control end of the control unit, the third end of the coil control unit is electrically connected with the first end of the power supply voltage reduction circuit, and the second end of the power supply voltage reduction circuit is electrically connected with the first end of the coil. The first channel is formed among the second end of the coil control unit, the first end of the coil pull-in circuit, the second end of the coil pull-in circuit, the first end of the coil, the second end of the coil, the first end of the coil release circuit, the second end of the coil release circuit and the fourth control end of the coil control unit. A second channel is formed among the third end of the coil control unit, the first end of the power supply voltage reducing circuit, the second end of the power supply voltage reducing circuit, the first end of the coil, the second end of the coil release circuit and the fourth control end of the coil control unit.

And the coil control unit is used for transmitting a first control signal to the coil release circuit when the first voltage represents that the direct current input power supply voltage is smaller than the second pull-in voltage, and the first control signal is used for closing the first channel and the second channel.

The coil control unit is further configured to send a first enable signal to the power supply voltage reduction circuit when the first voltage indicates that the dc input power supply voltage is greater than the second pull-in voltage and less than the first pull-in voltage, where the first enable signal is used to control the power supply voltage reduction circuit not to output a turn-on voltage and a turn-on current, so that the second channel is turned off. The coil attracting circuit is in an off state so that the first channel is closed.

The coil control unit is further used for sending a pulse signal to the coil action unit, transmitting a second control signal to the coil release circuit and sending a second enabling signal to the power supply voltage reducing circuit when the first voltage indicates that the direct current input power supply voltage is greater than or equal to the first pull-in voltage. When the level of the pulse signal is high, the coil pull-in circuit and the coil release circuit are controlled to be conducted so as to conduct the first channel. When the level of the pulse signal is low, the second enable signal is used for controlling the power supply voltage-reducing circuit to output a conducting voltage and a conducting current, and the second control signal is used for controlling the coil release circuit to conduct so as to conduct the second channel. The coil attracting circuit is in an off state so that the first channel is closed.

Based on the above, the coil action unit controls the power supply voltage reducing circuit, the coil attracting circuit and the coil releasing circuit in the coil action unit to be conducted or closed through the coil control unit, so that stable attracting or immediate releasing of the coil is realized.

In one possible design, the coil pull-in circuit includes: the first transistor, the second transistor, the third transistor, the fourth transistor, the fifth transistor, the first diode, the second diode, the first resistor, the second resistor, the third resistor, the fourth resistor, the fifth resistor, the sixth resistor, the seventh resistor, the eighth resistor, the ninth resistor, the first capacitor and the second capacitor.

The first end of the second capacitor is electrically connected with the second end of the power supply access unit, the second end of the second capacitor is grounded, the first end of the sixth resistor is electrically connected with the second end of the coil control unit, the second end of the sixth resistor is electrically connected with the first end of the second transistor, the first connection point is arranged between the second end of the sixth resistor and the first end of the second transistor, the second end of the second transistor is electrically connected with the third connection point, the third connection point is grounded, the second end of the seventh resistor is electrically connected with the second connection point, the first end of the first resistor is electrically connected with the fourth connection point, the fourth connection point is arranged between the third end of the third resistor, the third connection point is electrically connected with the third end of the fourth resistor, the third connection point is arranged between the third end of the third resistor, the third connection point is electrically connected with the fourth end of the fourth resistor, the third connection point is arranged between the third connection point is electrically connected with the third end of the third resistor, the third connection point is arranged between the third connection point of the third resistor and the fourth connection point, the third connection point is electrically connected with the third connection point of the third resistor, the first end of the fifth resistor is electrically connected to the first end of the fifth transistor, the second end of the fifth transistor is electrically connected to a ninth connection point, the ninth connection point is disposed between the sixth connection point and the first end of the second resistor, the third end of the fifth transistor is electrically connected to the second end of the third resistor, the first end of the first diode is electrically connected to the tenth connection point, the tenth connection point is disposed between the ninth connection point and the second end of the fifth transistor, the second end of the first diode is electrically connected to the eleventh connection point, the eleventh connection point is disposed between the third end of the fifth transistor and the second end of the third resistor, the first end of the third resistor is electrically connected to the first end of the first transistor, the first end of the first capacitor is electrically connected to the twelfth connection point, the twelfth connection point is disposed between the ninth connection point and the tenth connection point, the second end of the first capacitor is electrically connected to the thirteenth connection point, the first end of the first diode is electrically connected to the seventeenth connection point of the third resistor, the fourth connection point is disposed between the fourteenth connection point and the seventeenth connection point of the fourth resistor, the first end of the fourth resistor is electrically connected to the seventeenth connection point, the seventeenth connection point is disposed between the second end of the eighth resistor and the first end of the ninth resistor.

In one possible design, the coil release circuit includes: a sixth transistor, a seventh transistor, a third diode, a fourth diode, a fifth diode, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, and a third capacitor.

The second end of the fourteenth resistor is electrically connected with the fourth control end of the coil control unit, the first end of the fourteenth resistor is electrically connected with the first end of the seventh transistor, the second end of the seventh transistor is grounded, the third end of the seventh transistor is electrically connected with the second end of the thirteenth resistor, the first end of the thirteenth resistor is electrically connected with the eighth connection point, the eighth connection point is arranged between the second end of the eleventh resistor and the first end of the thirteenth resistor, the second end of the twelfth resistor is electrically connected with the third end of the power supply access unit, the first end of the eleventh resistor is electrically connected with the second end of the fifth diode, the first end of the fifth diode is electrically connected with the first end of the sixth transistor, the second end of the sixth transistor is electrically connected with the second end of the coil, the third end of the sixth transistor is electrically connected with the third connection point, the third connection point is grounded, the first end of the third diode is electrically connected with the ninth connection point, the ninth connection point is arranged between the second end of the sixth transistor and the second end of the coil, the second end of the eleventh resistor is electrically connected with the first end of the thirteenth connection point, the second connection point is arranged between the tenth connection point and the fourth connection point is arranged between the tenth connection point and the fifth connection point, the fifth connection point is arranged between the fourth connection point and the fifth connection point and the twenty-second connection point is arranged between the fourth connection point and the fifth connection point and the twenty-third connection point, the first end of the third capacitor is electrically connected to a twenty-fifth connection point, the twenty-fifth connection point is disposed between the twenty-third connection point and the first end of the fifth diode, the second end of the third capacitor is electrically connected to a twenty-fourth connection point, and the twenty-fourth connection point is disposed between the twenty-second connection point and the second end of the tenth resistor.

In one possible design, the power supply step-down circuit includes: an eighth transistor, a sixth diode, a seventh diode, an eighth diode, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a twentieth resistor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a seventh capacitor, an eighth capacitor, a ninth capacitor, a first inductor, a first buck module, and a second buck module.

The first end of the first voltage dropping module and the first end of the fourth capacitor are electrically connected with the second end of the power supply access unit, the second end of the fourth capacitor is grounded, the fourth end of the first voltage dropping module and the first end of the fifteenth resistor are electrically connected with the third end of the control unit, the second end of the fifteenth resistor is grounded, the fifth end of the first voltage dropping module, the sixth end of the first voltage dropping module, the seventh end of the first voltage dropping module, the eighth end of the first voltage dropping module and the ninth end of the first voltage dropping module are grounded, the second end of the first voltage dropping module is electrically connected with the first end of the first inductor, the second end of the first inductor is electrically connected with the first end of the seventh diode, the second end of the seventh diode is electrically connected with the first end of the connecting coil, the second end of the sixth diode is electrically connected with the twenty-fourth connecting point, the twenty-fourth connecting point is arranged between the second end of the first voltage dropping module and the first end of the first inductor, the first end of the sixth diode is grounded, the first end of the sixteenth resistor is electrically connected with a twenty-fifth connection point, the twenty-fifth connection point is arranged between the second end of the first inductor and the first end of the seventh diode, the second end of the sixteenth resistor is electrically connected with the first end of the seventeenth resistor, the second end of the seventeenth resistor is grounded, the third end of the first voltage dropping module is electrically connected with a twenty-sixth connection point, the twenty-sixth connection point is arranged between the second end of the sixteenth resistor and the first end of the seventeenth resistor, the first end of the fifth capacitor is electrically connected with a twenty-seventh connection point, the twenty-seventh connection point is arranged between the twenty-fifth connection point and the first end of the seventh diode, the first end of the sixth capacitor is electrically connected with a twenty-eighth connection point, the twenty-eighth connection point is arranged between the twenty-seventh connection point and the first end of the seventh diode, the second end of the sixth capacitor and the second end of the fifth capacitor are grounded. The first end of the eighteenth resistor and the first end of the nineteenth resistor are both electrically connected with the second end of the power supply access unit, the second end of the eighteenth resistor is electrically connected with the second end of the eighth transistor, the first end of the eighth transistor is electrically connected with the first end of the eighth diode, the second end of the eighth diode is grounded, the second end of the nineteenth resistor is electrically connected with the twenty-ninth connection point, the twenty-ninth connection point is arranged between the first end of the eighth transistor and the first end of the eighth diode, the third end of the eighth transistor is electrically connected with the first end of the twenty-resistor, the second end of the twenty-resistor is electrically connected with the third end of the second voltage dropping module, the first end of the seventh capacitor is electrically connected with the thirty-third connection point, the thirty-third connection point is arranged between the second end of the twenty-resistor and the third end of the second voltage dropping module, the first end of the eighth capacitor is electrically connected with the thirty-third connection point, the thirty-third connection point is arranged between the thirty-third connection point and the third end of the second voltage dropping module, the second end of the thirty-eighth capacitor is electrically connected with the thirty-third connection point, the second end of the thirty-third capacitor is electrically connected with the thirty-third connection point of the thirty-third capacitor, the thirty-fourth capacitor is arranged between the thirty-third connection point and the thirty-fourth connection point is electrically connected with the thirty-third connection point, the thirty-fifth connection point is disposed between the first end of the ninth capacitor and the fifth end of the coil control unit.

In one possible design, the power access unit includes: an anti-reverse connection circuit and a power supply detection circuit.

The first end of the reverse connection preventing circuit is electrically connected with the first end of the power supply detecting circuit, the first end of the power supply voltage reducing circuit and the first end of the coil attracting circuit, the second end of the power supply detecting circuit is electrically connected with the first input end of the control unit, and the second end of the reverse connection preventing circuit is electrically connected with the third end of the coil releasing circuit.

The reverse connection preventing circuit is used for connecting direct current input power supply voltage and outputting the direct current input power supply voltage to the coil pull-in circuit, the coil release circuit and the power supply voltage reducing circuit.

And the power supply detection circuit is used for detecting the direct current input power supply voltage input from the anti-reverse connection circuit, generating a first voltage and sending the first voltage to the coil control unit.

Based on the power supply, the power supply access unit supplies power to other circuits in the control circuit of the low-voltage direct-current contactor, the functions of reverse connection prevention and power supply voltage detection of power supply input are realized, circuit damage possibly caused by reverse connection of the positive electrode and the negative electrode of the input end of the power supply is avoided, meanwhile, the change condition of direct-current input power supply voltage is input to the coil control unit, and the basis for the attraction or release of the contactor in the control circuit is provided for the coil control unit.

In one possible design, the anti-reverse circuit includes: the rectifier module, ninth diode, twelfth utmost point pipe, twenty-first resistance and tenth electric capacity.

The second end of the rectifier module is electrically connected with an input power supply, the first end of the twenty-first resistor is electrically connected with a thirty-sixth connection point, the thirty-sixth connection point is arranged between the second end of the rectifier module and a direct-current input power supply voltage, the first end of the ninth diode is electrically connected with a thirty-seventh connection point, the thirty-seventh connection point is arranged between the second end of the rectifier module and the thirty-sixth connection point, the second end of the tenth diode is electrically connected with a third end of a circuit release circuit, the second end of the ninth diode is electrically connected with a thirty-eighth connection point, the thirty-eighth connection point is arranged between the second end of the twelfth diode and the third end of the coil release circuit, the second end of the rectifier module is electrically connected with a thirty-ninth connection point, the first end of the tenth diode is electrically connected with a fortieth connection point, the fortieth connection point is arranged between the first end of the rectifier module and the thirty-ninth connection point, the third end of the rectifier module is electrically connected with the fortieth connection point, the fortieth connection point is connected with the fourth connection point of a circuit, the fortieth connection point is connected with the fortieth circuit, the fortieth connection point is connected with the fourth connection point of a fortieth circuit, and the fortieth connection point is electrically connected with the fortieth connection point is connected with the fourth connection point.

In one possible design, the power detection circuit includes: twenty-second resistor, twenty-third resistor, twenty-fourth resistor, eleventh capacitor and clamping module.

The first end of the twenty-second resistor is electrically connected with the forty-third connection point, the second end of the twenty-second resistor is electrically connected with the first end of the twenty-third resistor, the second end of the twenty-third resistor is electrically connected with the first end of the twenty-fourth resistor, the second end of the twenty-fourth resistor is grounded, the first end of the clamping module is grounded, the fourth end of the clamping module is electrically connected with the forty-fourth connection point, the forty-fourth connection point is arranged between the second end of the twenty-third resistor and the first end of the twenty-fourth resistor, the second end of the clamping module is connected with a direct current input power supply voltage, the third end of the clamping module is electrically connected with the first input end of the control unit, the first end of the eleventh capacitor is electrically connected with the forty-fifth connection point, and the forty-fifth connection point is arranged between the first input end of the coil control unit and the third end of the clamping module.

In one possible design, the pulse width of the pulse signal when the dc input power voltage is greater than or equal to the first pull-in voltage and less than the third pull-in voltage is the first pulse width.

The pulse width of the pulse signal when the direct current input power supply voltage is larger than or equal to the third pull-in voltage is the second pulse width.

The first pulse width is greater than the second pulse width.

In a second aspect, the present application provides a low voltage dc contactor comprising: a coil and a control circuit for a low voltage dc contactor as in any of the possible designs described above.

The advantages provided by the second aspect and the possible designs of the second aspect may be referred to the advantages provided by the first aspect and the possible embodiments of the first aspect, and are not described herein.

Drawings

Fig. 1 is a schematic diagram of a control circuit structure of a low-voltage dc contactor according to an embodiment of the present application;

fig. 2 is a schematic structural diagram of a coil action unit in a control circuit of a low-voltage dc contactor according to an embodiment of the present application;

FIG. 3 is a schematic diagram of a coil pull-in circuit in a control circuit of a low voltage DC contactor according to an embodiment of the present application;

FIG. 4 is a schematic diagram of a coil release circuit in a control circuit of a low voltage DC contactor according to an embodiment of the present application;

FIG. 5 is a schematic diagram of a power supply step-down circuit in a control circuit of a low voltage DC contactor according to an embodiment of the present application;

FIG. 6 is a schematic diagram of the power supply connections in the control circuit of a low voltage DC contactor according to an embodiment of the present application;

fig. 7 is a schematic structural diagram of a power supply access unit in a control circuit of a low-voltage dc contactor according to an embodiment of the present application;

Fig. 8 is a schematic circuit diagram of a power supply access unit in a control circuit of a low-voltage dc contactor according to an embodiment of the present application;

Reference numerals illustrate:

110-a power supply access unit; 120-coil action unit; 130-a coil control unit; 140-coil; 210-coil pull-in circuit; 220-a power supply step-down circuit; 230-coil release circuitry; 310-anti-reverse circuit; 320-power detection circuitry.

Detailed Description

In the present application, "at least one" means one or more, and "a plurality" means two or more. "and/or", describes an association relationship of an association object, and indicates that there may be three relationships, for example, a and/or B, and may indicate: a alone, a and B together, and B alone, wherein a, B may be singular or plural. The character "/" generally indicates that the context-dependent object is an "or" relationship. "at least one of" or the like means any combination of these items, including any combination of single item(s) or plural items(s). For example, at least one (one) of a, b, or c alone may represent: a alone, b alone, c alone, a combination of a and b, a combination of a and c, b and c, or a combination of a, b and c, wherein a, b, c may be single or plural. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

The terms "center," "longitudinal," "transverse," "upper," "lower," "left," "right," "front," "rear," and the like refer to an orientation or positional relationship based on that shown in the drawings, merely for convenience of description and to simplify the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the application.

The terms "connected," "connected," and "connected" are to be construed broadly, and may refer to, for example, electrical or signal connections in addition to physical connections, e.g., direct connections, i.e., physical connections, or indirect connections via at least one element therebetween, such as long as electrical circuit communication is achieved, and communications within two elements; signal connection may refer to signal connection through a medium such as radio waves, in addition to signal connection through a circuit. The specific meaning of the above terms in the present application will be understood in specific cases by those of ordinary skill in the art.

Exemplary embodiments of the present application provide a low voltage dc contactor and a control circuit for the low voltage dc contactor.

The low voltage dc contactor may include: coil 140 and control circuitry for the low voltage dc contactor. The control circuit of the low-voltage dc contactor is used to control whether current flows through the coil 140 in different ranges of the input power voltage, thereby engaging or disengaging the coil 140. The coil 140 is used for sucking when current flows through both ends of the coil, and discharging when current is not conducted through both ends of the coil.

Next, referring to fig. 1, fig. 1 is a schematic diagram of a control circuit of a low-voltage dc contactor according to an embodiment of the application. As shown in fig. 1, the control circuit of the low voltage dc contactor of the present application may include: coil control section 130, power supply access section 110, and coil operation section 120.

A first end of the power access unit 110 is electrically connected to a first input of the control unit 130. The second end of the coil control unit 130 is electrically connected to the first end of the coil action unit 120, the first end of the coil action unit 120 is electrically connected to the first end of the coil 140, the second end of the coil 140 is electrically connected to the third end of the coil action unit 120, the third end of the coil action unit 120 is electrically connected to the fourth control end of the coil control unit 130, the third end of the coil control unit 130 is electrically connected to the second end of the coil action unit 120, and the second end of the coil action unit 120 is electrically connected to the first end of the coil 140. Wherein a first channel is formed between the second end of the coil control unit 130, the first end of the coil action unit 120, the first end of the coil 140, the second end of the coil 140, the third end of the coil action unit 120, and the fourth control end of the coil control unit 130. A second channel is formed between the third end of the coil control unit 130, the second end of the coil action unit 120, the first end of the coil 140, the second end of the coil 140, the third end of the coil action unit 120, and the fourth control end of the coil control unit 130.

In fig. 1, a first end of the power supply access unit 110 is denoted as 1, a first end of the coil action unit 120 is denoted as 1, a second end of the coil action unit 120 is denoted as 2, a third end of the coil action unit 120 is denoted as 3, a first end of the coil control unit 130 is denoted as 1, a second end of the coil control unit 130 is denoted as 2, a third end of the coil control unit 130 is denoted as 3, a fourth end of the coil control unit 130 is denoted as 4, a first end of the coil 140 is denoted as 1, a second end of the coil 140 is denoted as 2, a first channel is denoted as Path1, and a second channel is denoted as Path2.

When the direct current input power supply voltage is smaller than the first pull-in voltage, the control circuit of the low-voltage direct current contactor controls the contactor to make the coil 140 of the contactor incapable of being pulled in. When the direct current input power supply voltage is larger than the minimum pull-in circuit, the contactor is controlled to enable the coil 140 of the contactor to be stably pulled in. The voltage value of the first pull-in voltage may be 16V or other voltage values.

The power access unit 110 may directly access the dc input power voltage, and send a first voltage Uadc to the coil control unit 130, where the first voltage Uadc is used to represent a change situation of the dc input power voltage. When the coil control unit 130 receives the first voltage, it determines a voltage range in which the first voltage Uadc is located. When the first voltage Uadc indicates that the dc input power voltage is less than the first pull-in voltage, the first channel and the second channel are controlled to be closed, so that the coil 140 is released. When the first voltage Uadc indicates that the dc input power supply voltage is greater than or equal to the first pull-in voltage, a pulse signal is transmitted to the coil action unit 120.

When the level of the pulse signal is high, the first channel is controlled to be turned on and the second channel is controlled to be turned off, so that the coil 140 is attracted. When the level of the pulse signal is low, the second channel is controlled to be turned on and the first channel is controlled to be turned off, so that the coil 140 is attracted.

When it is required to control the second channel to be turned on or off, the coil control unit 130 transmits an enable signal en_pwr to the coil action unit 120, where the transmitted enable signal en_pwr includes a first enable signal and a second enable signal, the first enable signal may control the second channel to be turned off, and the second enable signal may control the second channel to be turned on.

When the direct current input power supply voltage is larger than or equal to the first pull-in voltage and smaller than the third pull-in voltage, the pulse width of the pulse signal is the first pulse width. When the direct current input power supply voltage is greater than or equal to the third pull-in voltage, the pulse width of the pulse signal is the second pulse width. The first pulse width is greater than the second pulse width. The first pulse width may be 120ms, or other pulse width values greater than the second pulse width, the second pulse width may be 85ms, or other pulse width values smaller than the first pulse width, and the third pull-in voltage may be 20V, or other voltage values greater than the first pull-in voltage.

In fig. 1, when the first channel needs to be controlled to be closed, the second end of the coil control unit 130 does not send a pulse signal to the first end of the coil action unit 120, so that the first end of the coil action unit 120 and the first end of the coil 140 cannot flow current, and thus the coil 140 cannot be attracted, and the first channel is closed.

When the second channel needs to be controlled to be closed, the third end of the coil control unit 130 does not send the first enabling signal to the second end of the coil action unit 120, so that the second end of the coil action unit 120 and the first end of the coil 140 cannot flow current, and therefore the coil 140 cannot be attracted, and the second channel is closed.

When the first channel needs to be controlled to be turned on, the second end of the coil control unit 130 sends a pulse signal to the first end of the coil action unit 120, so that current flows from the first end of the coil action unit 120 to the first end of the coil 140. The fourth control terminal of the coil control unit 130 transmits a control signal rel_ctl to the third terminal of the coil action unit 120, so that current flows to the second terminal of the coil 140 through the third terminal of the coil action unit 120. Current flows between the first and second ends of the coil 140, causing the coil 140 to draw in, forming a conductive first path.

When the second channel needs to be controlled to be turned on, the third end of the coil control unit 130 sends a first enable signal to the second end of the coil action unit 120, so that current flows from the second end of the coil action unit 120 to the first end of the coil 140. The fourth control terminal of the coil control unit 130 transmits a control signal rel_ctl to the third terminal of the coil action unit 120, so that current flows to the second terminal of the coil 140 through the third terminal of the coil action unit 120. Current flows between the first end and the second end of the coil 140, so that the coil 140 is attracted to form a conductive second channel.

The first enable signal may control the coil action unit 120 not to output the turn-on voltage and the turn-on current, so that the second channel is closed. The second enable signal may control the coil action unit 120 to output a turn-on voltage and a turn-on current, so that the first end of the coil 140 is turned on.

Next, a specific implementation of the coil action unit 120 in the control circuit of the low voltage dc contactor according to the present application will be described in detail with reference to fig. 2.

Referring to fig. 2, fig. 2 is a schematic diagram illustrating a coil action unit 120 in a control circuit of a low-voltage dc contactor according to an embodiment of the application. In fig. 2, the coil action unit 120 includes: a power supply voltage reducing circuit 220, a coil pull-in circuit 210, and a coil release circuit 230.

The first end of the power supply access unit 110 is electrically connected to the first input end of the coil control unit 130, the second end of the coil control unit 130 is electrically connected to the first end of the coil pull-in circuit 210, the second end of the coil pull-in circuit 210 is electrically connected to the first end of the coil 140, the second end of the coil 140 is electrically connected to the first end of the coil release circuit 230, the second end of the coil release circuit 230 is electrically connected to the fourth control end of the coil control unit 130, the third end of the coil control unit 130 is electrically connected to the first end of the power supply step-down circuit 220, and the second end of the power supply step-down circuit 220 is electrically connected to the first end of the coil 140. Wherein a first channel is formed between the second end of the coil control unit 130, the first end of the coil pull-in circuit 210, the second end of the coil pull-in circuit 210, the first end of the coil 140, the second end of the coil 140, the first end of the coil release circuit 230, the second end of the coil release circuit 230, and the fourth control end of the coil control unit 130. A second channel is formed between the third terminal of the coil control unit 130, the first terminal of the power supply voltage reducing circuit 220, the second terminal of the power supply voltage reducing circuit 220, the first terminal of the coil 140, the second terminal of the coil 140, the first terminal of the coil release circuit 230, the second terminal of the coil release circuit 230, and the fourth control terminal of the coil control unit 130.

In fig. 2, a first end of the coil pull-in circuit 210 is denoted as 1, a second end of the coil pull-in circuit 210 is denoted as 2, a first end of the coil release circuit 230 is denoted as 1, a second end of the coil release circuit 230 is denoted as 2, a first end of the power supply voltage reducing circuit 220 is denoted as 1, and a second end of the power supply voltage reducing circuit 220 is denoted as 2.

The coil action unit 120 is composed of a power supply voltage reducing circuit 220, a coil pull-in circuit 210, and a coil release circuit 230. The coil 140 is stably attracted or immediately released by controlling the on or off of the above three circuits included in the coil action unit 120 by the coil control unit 130.

The coil control unit 130 controls the turn-on or turn-off of the coil release circuit 230 by transmitting a control signal rel_ctl to the coil release circuit 230, thereby controlling the turn-on or turn-off of the first and second channels. The control signal rel_ctl includes a first control signal and a second control signal, the first control signal can control the coil release circuit 230 not to output the turn-on voltage and the turn-on current, so that the second channel is turned off, the second control signal can control the coil release circuit 230 to output the turn-on voltage and the turn-on current, so that the second segment of the coil 140 is turned on, and when the first end of the coil 140 is also turned on, the second channel is turned on.

When the first voltage Uadc indicates that the dc input power voltage is less than the second pull-in voltage, the coil control unit 130 transmits a first control signal to the coil release circuit 230, and the first control signal may close the first channel and the second channel. For example, the second pull-in voltage may be 5V, or may be another voltage value smaller than the first pull-in voltage. When the first voltage Uadc represents that the dc input power voltage is less than 5V, the fourth control terminal of the coil control unit 130 controls the second terminal of the coil release circuit 230 to the second terminal of the coil 140 to switch from the conductive state to the non-conductive state, thereby disconnecting the conductive current between the first terminal and the second terminal of the coil 140 and immediately releasing the coil 140.

When the first voltage Uadc indicates that the dc input power voltage is greater than the second pull-in voltage and less than the first pull-in voltage, the coil control unit 130 sends a first enable signal to the power supply voltage-reducing circuit 220, where the first enable signal may control the power supply voltage-reducing circuit 220 not to output the on voltage and the on current, so that the second channel is closed. Wherein the coil pull-in circuit 210 is in an off state, thereby closing the first channel.

When the first voltage Uadc indicates that the dc input power supply voltage is greater than or equal to the first pull-in voltage, the coil control unit 130 transmits a pulse signal to the coil action unit 120, transmits a second control signal to the coil release circuit 230, and transmits a second enable signal to the power supply step-down circuit 220. When the level of the pulse signal is high, the coil pull-in circuit 210 and the coil release circuit 230 are controlled to be turned on to turn on the first channel. When the level of the pulse signal is at a low level, the second enable signal is used to control the power supply voltage-reducing circuit 220 to output the on voltage and the on current, and the second control signal is used to control the coil release circuit 230 to be turned on to turn on the second channel. Wherein the coil pull-in circuit 210 is in an off state, thereby closing the first channel.

Wherein forming the first channel includes:

The second terminal of the coil control unit 130 sends a pulse signal to the first terminal of the coil pull-in circuit 210, causing current to flow to the first terminal of the coil 140 through the conductive coil pull-in circuit 210. The fourth control terminal of the coil control unit 130 sends a second control signal to the second terminal of the coil release circuit 230, so that current flows to the second terminal of the coil 140 through the first terminal of the coil release circuit 230, and current flows between the first terminal and the second terminal of the coil 140, so that the coil 140 is attracted to form a first channel.

Forming the second channel includes:

The third terminal of the coil control unit 130 transmits a first enable signal to the first terminal of the power supply voltage-reducing circuit 220, causing a current to flow from the second terminal of the turned-on power supply voltage-reducing circuit 220 to the first terminal of the coil 140. The fourth control terminal of the coil control unit 130 sends a second control signal to the second terminal of the coil release circuit 230, so that the current flows to the second terminal of the coil 140 through the first terminal of the turned-on coil 140 release unit, and the current flows between the first terminal and the second terminal of the coil 140, so that the coil 140 is attracted to form a second channel.

Next, a specific implementation of the coil pull-in circuit 210 in the control circuit of the low voltage dc contactor according to the present application will be described in detail with reference to fig. 3.

Referring to fig. 3, fig. 3 is a schematic diagram of a coil pull-in circuit 210 in a control circuit of a low voltage dc contactor according to an embodiment of the application. In fig. 3, the coil pull-in circuit 210 includes: the first transistor Q2, the second transistor Q6, the third transistor Q7, the fourth transistor Q8, the fifth transistor Q4, the first diode D7, the second diode D8, the first resistor R13, the second resistor R14, the third resistor R15, the fourth resistor R16, the fifth resistor R20, the sixth resistor R21, the seventh resistor R24, the eighth resistor R22, the ninth resistor R23, the first capacitor C9, and the second capacitor C10.

The first end of the second capacitor C10 is electrically connected to the second end of the power supply access unit 110, the second end of the second capacitor C10 is grounded, the first end of the sixth resistor R21 is electrically connected to the second end of the control unit 130, the second end of the sixth resistor R21 is electrically connected to the first end of the second transistor Q6, the first end of the seventh resistor R24 is electrically connected to the first connection point, the first connection point is disposed between the second end of the sixth resistor R21 and the first end of the second transistor Q6, the second end of the second transistor Q6 is electrically connected to the third connection point, the third connection point is grounded, the second end of the seventh resistor R24 is electrically connected to the second connection point, the first end of the first resistor R13 is electrically connected to the fourth connection point, the fourth connection point is disposed between the second input end of the power supply access unit 110 and the first end of the second capacitor C10, the first end of the first resistor R13 is electrically connected to the first end of the third transistor Q7, the third end of the second transistor Q6 is electrically connected to a fifth connection point, the fifth connection point is disposed between the second end of the first resistor R13 and the first end of the second transistor Q6, the second end of the third transistor Q7 is electrically connected to the third connection point, the first end of the second resistor R14 is electrically connected to a sixth connection point, the sixth connection point is disposed between the fourth connection point and the first resistor R13, the second end of the second resistor R14 is electrically connected to the third end of the third transistor Q7, the first end of the fourth transistor Q8 is electrically connected to the first end of the eighth resistor R22, the second end of the fourth transistor Q8 is electrically connected to the second end of the fifth resistor R20, the seventh connection point is electrically connected to the eighth connection point, the seventh connection point is disposed between the second end of the second resistor R14 and the third end of the third transistor Q7, the eighth connection point is disposed between the third end of the fourth transistor Q8 and the second end of the fifth resistor R20, the first end of the fifth resistor R20 is electrically connected to the first end of the fifth transistor Q4, the second end of the fifth transistor Q4 is electrically connected to the ninth connection point, the third end of the fifth transistor Q4 is electrically connected to the second end of the third resistor R15, the first end of the first diode D7 is electrically connected to the tenth connection point, the tenth connection point is disposed between the ninth connection point and the second end of the fifth transistor Q4, the second end of the first diode D7 is electrically connected to the eleventh connection point, the first end of the third resistor R15 is electrically connected to the first end of the first transistor Q2, the first end of the first capacitor C9 is electrically connected to the twelfth connection point, the second end of the first capacitor C9 is electrically connected to the tenth connection point, the thirteenth connection point is disposed between the first end of the thirteenth capacitor C9 and the fourth end of the fifth resistor R4, the fifth connection point is electrically connected to the fourth end of the fifth resistor R2, the fifth connection point is disposed between the second end of the fifth resistor R2 and the fifth end of the fifth resistor R2, the fifth connection point is electrically connected to the fourth end of the fifth resistor R23, the fifth resistor R2 is electrically connected to the fifth connection point is disposed between the fourth end of the fifth resistor R2 and the fifth end of the fifth resistor R15, the fifth end of the fifth resistor R2 is electrically connected to the fifth end of the fifth resistor R4, the fifth connection point is electrically connected to the fifth end of the fifth resistor R15, the fifth end of the fifth resistor is electrically connected to the fifth connection point is between the fifth end of the fifth junction, the second terminal of the second diode D8 is electrically connected to a seventeenth connection point, which is disposed between the second terminal of the eighth resistor R22 and the first terminal of the ninth resistor R23.

In fig. 3, a first end of the first transistor Q2 is denoted as 1, a second end of the first transistor Q2 is denoted as 2, a third end of the first transistor Q2 is denoted as 3, a first end of the second transistor Q6 is denoted as 1, a second end of the second transistor Q6 is denoted as 2, a third end of the second transistor Q6 is denoted as 3, a first end of the third transistor Q7 is denoted as 1, a second end of the third transistor Q7 is denoted as 2, a third end of the third transistor Q7 is denoted as 3, a first end of the fourth transistor Q8 is denoted as 1, a second end of the fourth transistor Q8 is denoted as 2, a third end of the fourth transistor Q8 is denoted as 3, a first end of the fifth transistor Q4 is denoted as 1, a second end of the fifth transistor Q4 is denoted as 2, and a third end of the fifth transistor Q4 is denoted as 3.

In fig. 3, the fourth connection point is connected to the input voltage +24v by being connected to the second input terminal of the power supply connection unit 110. The first terminal of the sixth resistor R21 is electrically connected to the second terminal of the coil control unit 130, so that the coil control unit 130 inputs the pulse signal delay_ctl to the coil pull-in circuit 210, thereby controlling the coil pull-in circuit 210. The sixteenth connection point is further connected to the third contact terminal JK3, and the third contact terminal JK3 has a suction condition when the coil 140 is turned on.

Next, a specific implementation of the coil release circuit 230 in the control circuit of the low voltage dc contactor according to the present application will be described in detail with reference to fig. 4.

Referring to fig. 4, fig. 4 is a schematic diagram of a coil release circuit 230 in a control circuit of a low voltage dc contactor according to an embodiment of the application. In fig. 4, the coil release circuit 230 includes: a sixth transistor Q3, a seventh transistor Q5, a third diode D9, a fourth diode D10, a fifth diode D6, a tenth resistor R17, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R18, a fourteenth resistor R19, and a third capacitor C11.

The second end of the fourteenth resistor R19 is electrically connected to the fourth control end of the coil control unit 130, the first end of the fourteenth resistor R19 is electrically connected to the first end of the seventh transistor Q5, the second end of the seventh transistor Q5 is grounded, the third end of the seventh transistor Q5 is electrically connected to the second end of the thirteenth resistor R18, the first end of the thirteenth resistor R18 is electrically connected to the second end of the eleventh resistor R11, the first end of the twelfth resistor R12 is electrically connected to the eighteenth connection point, the eighteenth connection point is provided between the second end of the eleventh resistor R11 and the first end of the thirteenth resistor R18, the second end of the twelfth resistor R12 is electrically connected to the third end of the power supply access unit 110, the first end of the eleventh resistor R11 is electrically connected to the second end of the fifth diode D6, the first end of the fifth diode D6 is electrically connected to the first end of the sixth transistor Q3, the second end of the thirteenth transistor Q3 is electrically connected to the second end of the thirteenth resistor R11, the third end of the thirteenth resistor R18 is electrically connected to the thirteenth end of the thirteenth resistor R11, the third end of the thirteenth resistor Q3 is electrically connected to the twenty-eighth connection point, the third end of the twenty-third transistor Q3 is electrically connected to the twenty-eighth connection point is connected to the twenty-third end of the twenty-third resistor Q3, the twenty-third connection point is 9 is electrically connected to the twenty-third end of the twenty-third connection point between the twenty-third end of the twenty-third resistor Q3 and the twenty-third resistor, and the twenty-third connection point is 10 is connected to the twenty-third end 7 is connected to the twenty-third end of the twenty-third connection point between the twenty-third end of the twenty-third resistor, and the twenty-third connection point is, the twenty-second connection point is disposed between the twenty-second connection point and the first end of the fourth diode D10, the first end of the third capacitor C11 is electrically connected to the twenty-fifth connection point, the twenty-fifth connection point is disposed between the twenty-third connection point and the first end of the fifth diode D6, the second end of the third resistor R15 capacitor is electrically connected to the twenty-fourth connection point, and the twenty-fourth connection point is disposed between the twenty-second connection point and the second end of the tenth resistor R17.

In fig. 4, the first terminal of the sixth transistor Q3 is denoted as 1, the second terminal of the sixth transistor Q3 is denoted as 2, the third terminal of the sixth transistor Q3 is denoted as 3, the first terminal of the seventh transistor Q5 is denoted as 1, the second terminal of the seventh transistor Q5 is denoted as 2, and the third terminal of the seventh transistor Q5 is denoted as 3.

In fig. 4, the third terminal of the power access unit 110 provides the second input voltage Release Vol to the coil Release circuit 230 through the second terminal of the twelfth resistor. The first terminal of the fourteenth resistor R19 is connected to the fourth control terminal of the coil control unit 130 to cause the coil control unit 130 to transmit the control signal rel_ctl to the coil release circuit 230, thereby controlling the coil release circuit 230. The nineteenth connection point is also connected to the fourth contact terminal JK4, and when the coil 140 is turned on, the fourth contact terminal JK4 has a suction condition and can be sucked with the third contact terminal JK3 having a suction condition.

Next, a specific implementation of the power supply voltage reducing circuit 220 in the control circuit of the low voltage dc contactor according to the present application will be described in detail with reference to fig. 5.

Referring to fig. 5, fig. 5 is a schematic diagram of a power supply voltage reducing circuit 220 in a control circuit of a low voltage dc contactor according to an embodiment of the application. In fig. 5, the power supply voltage reducing circuit 220 includes: the voltage reducing circuit comprises an eighth transistor Q1, a sixth diode D2, a seventh diode D1, an eighth diode ZD1, a fifteenth resistor R4, a sixteenth resistor R1, a seventeenth resistor R3, an eighteenth resistor R8, a nineteenth resistor R10, a twentieth resistor R9, a fourth capacitor C3, a fifth capacitor C1, a sixth capacitor C2, a seventh capacitor C6, an eighth capacitor C7, a ninth capacitor C8, a first inductor L1, a first voltage reducing module U1 and a second voltage reducing module U2.

The first end of the first buck module U1 and the first end of the fourth capacitor C3 are electrically connected to the second end of the power supply access unit 110, the second end of the fourth capacitor C3 is grounded, the fourth end of the first buck module U1 and the first end of the fifteenth resistor R4 are electrically connected to the third end of the control unit 130, the second end of the fifteenth resistor R4 is grounded, the fifth end of the first buck module U1, the sixth end of the first buck module U1, the seventh end of the first buck module U1, the eighth end of the first buck module U1 and the ninth end of the first buck module U1 are grounded, the second end of the first buck module U1 is electrically connected to the first end of the first inductor L1, the second end of the first inductor L1 is electrically connected to the first end of the seventh diode D1, the second end of the seventh diode D1 is electrically connected to the first end of the connection coil 140, and the second end of the sixth diode D2 is electrically connected to the twenty-fourth connection point, the twenty-fourth connection point is arranged between the second end of the first voltage dropping module U1 and the first end of the first inductor L1, the first end of the sixth diode D2 is grounded, the first end of the sixteenth resistor R1 is electrically connected with the twenty-fifth connection point, the twenty-fifth connection point is arranged between the second end of the first inductor L1 and the first end of the seventh diode D1, the second end of the sixteenth resistor R1 is electrically connected with the first end of the seventeenth resistor R3, the second end of the seventeenth resistor R3 is grounded, the third end of the first voltage dropping module U1 is electrically connected with the twenty-sixth connection point, the twenty-sixth connection point is arranged between the second end of the sixteenth resistor R1 and the first end of the seventeenth resistor R3, the first end of the fifth capacitor C1 is electrically connected with the twenty-seventh connection point, the twenty-seventh connection point is arranged between the twenty-fifth connection point and the first end of the seventh diode D1, the first end of the sixth capacitor C2 is electrically connected with the twenty-eighth connection point, the twenty-eighth connection point is disposed between the twenty-seventh connection point and the first end of the seventh diode D1, and the second end of the sixth capacitor C2 and the second end of the fifth capacitor C1 are both grounded. The first end of the eighteenth resistor R8 and the first end of the nineteenth resistor R10 are both electrically connected to the second end of the power supply access unit 110, the second end of the eighteenth resistor R8 is electrically connected to the second end of the eighth transistor Q1, the first end of the eighth transistor Q1 is electrically connected to the first end of the eighth diode ZD1, the second end of the eighth diode ZD1 is grounded, the second end of the nineteenth resistor R10 is electrically connected to a twenty-ninth connection point, the twenty-ninth connection point is disposed between the first end of the eighth transistor Q1 and the first end of the eighth diode ZD1, the third end of the eighth transistor Q1 is electrically connected to the first end of the twentieth resistor R9, the second end of the twentieth resistor R9 is electrically connected to the third end of the second voltage reducing module U2, the first end of the seventh capacitor C6 is electrically connected to the thirty-connection point, the thirty-connection point is disposed between the second end of the twentieth resistor R9 and the third end of the second voltage reducing module U2, the first end of the eighth capacitor C7 is electrically connected with a thirty-second connection point, the thirty-second connection point is arranged between the thirty-fourth connection point and the third end of the second voltage dropping module U2, the second end of the ninth capacitor C8 and the second end of the seventh capacitor C6 are electrically connected with a thirty-fourth connection point, the thirty-fourth connection point is grounded, the second end of the eighth capacitor C7 is electrically connected with a thirty-second connection point, the thirty-second connection point is arranged between the thirty-fourth connection point and the second end of the seventh capacitor C6, the first end of the second voltage dropping module U2 is electrically connected with a thirty-third connection point, the thirty-third connection point is arranged between the thirty-fourth connection point and the thirty-second connection point, the first end of the ninth capacitor C8 is electrically connected with the fifth end of the coil control unit 130, the second end of the second voltage dropping module U2 and the fourth end of the second voltage dropping module U2 are electrically connected with the thirty-fifth connection point, the thirty-fifth connection point is disposed between the first end of the ninth capacitor C8 and the fifth end of the coil control unit 130.

In fig. 5, the first end of the eighth transistor Q1 is denoted as 1, the second end of the eighth transistor Q1 is denoted as 2, the third end of the eighth transistor Q1 is denoted as 3, the first end of the first buck module U1 is denoted as 1, the second end of the first buck module U1 is denoted as 2, the third end of the first buck module U1 is denoted as 3, the fourth end of the first buck module U1 is denoted as 4, the fifth end of the first buck module U1 is denoted as 5, the sixth end of the first buck module U1 is denoted as 6, the seventh end of the first buck module U1 is denoted as 7, the eighth end of the first buck module U1 is denoted as 8, the ninth end of the first buck module U1 is denoted as 9, the first end of the second buck module U2 is denoted as 1, the second end of the second buck module U2 is denoted as 2, the third end of the second buck module U2 is denoted as 3, and the fourth end of the second buck module U2 is denoted as 4.

In fig. 5, the first terminal of the eighteenth resistor R8 and the first terminal of the nineteenth resistor R10 are connected to the second terminal of the power supply unit 110, so as to provide the power supply voltage reducing circuit 220 with the first input voltage +24v. The third terminal of the first voltage reducing module U1 is connected to the third terminal of the coil control unit 130, so that the coil control unit 130 can output the enable signal en_pwr, and the power voltage reducing circuit 220 is controlled by the enable signal en_pwr. TP4, TP5, TP6, and TP7 are four test points of the power supply voltage reduction circuit 220 at which the power supply voltage reduction circuit 220 can be debugged and tested.

Next, a specific principle of the control circuit of the low voltage dc contactor of the present application will be described in detail with reference to the coil pull-in circuit 210 in the control circuit of the low voltage dc contactor of fig. 3, the coil release circuit 230 in the control circuit of the low voltage dc contactor of fig. 4, and the power supply voltage step-down circuit 220 in the control circuit of the low voltage dc contactor of fig. 5, and the specific procedure of the principle is as follows:

(1) When the range of the dc input power voltage vin_pwr is greater than or equal to the second pull-in voltage and less than the first pull-in voltage, for example, the range of the dc input power voltage is [5,16 ], the enable end of the coil control unit 130 outputs a high-level first enable signal, so that the fourth end of the first voltage reduction module U1 of the power voltage reduction circuit 220 is in a high-level state, the first voltage reduction module U1 of the power voltage reduction circuit 220 cannot output current, so that the power voltage reduction circuit 220 is not turned on, both the first channel and the second channel are turned off, and the coil 140 cannot be pulled in, thereby realizing the effects of saving energy and avoiding the malfunction of the contactor.

(2) When the range of the dc input power supply voltage vin_pwr is greater than or equal to the first pull-in voltage and less than the third pull-in voltage, for example, the range of the dc input power supply voltage is [16,20 ], the pulse signal terminal of the coil control unit 130 outputs a high level pulse of 120ms, the second terminal of the second transistor Q6 and the third terminal of the second transistor Q6 in the coil pull-in circuit 210 are turned on, so that the first terminal of the third transistor Q7 becomes low, and at this time, the voltage of the third terminal of the third transistor Q7 is high due to the dc input power supply voltage, so the first terminal of the fifth transistor Q4 is high, and the second terminal of the fifth transistor Q4 and the third terminal of the fifth transistor Q4 are turned off. At this time, the first terminal of the first transistor Q2 is at a low level, so the second terminal of the first transistor Q2 and the third terminal of the second transistor Q6 are turned on, so that current can flow from the coil pull-in circuit 210 to the first terminal of the coil 140 through the third contact terminal JK 3.

Meanwhile, the voltage range of the power supply access unit 110 input to the coil release circuit 230 is between 16V and 20V, and the control signal terminal of the coil control unit 130 outputs a second control signal to turn on the coil release circuit 230. Since the minimum voltage value of the input coil release circuit 230 is greater than the regulated voltage value of the fifth diode D6, the second terminal of the sixth transistor Q3 and the third terminal of the sixth transistor Q3 are turned on, so that current can flow from the coil release circuit 230 to the second terminal of the coil 140 through the fourth contact terminal JK 4.

Therefore, the coil 140 is supplied with current, so that a current path is formed in the coil 140, and the first channel is turned on, and at this time, the third contact terminal JK3 and the fourth contact terminal JK4 of the contactor are engaged.

After the pulse signal terminal of the coil control unit 130 outputs the high level pulse of 120ms, it goes low for 120ms, the second terminal of the second transistor Q6 and the third terminal of the second transistor Q6 in the coil pull-in circuit 210 are turned off, so that the first terminal of the third transistor Q7 goes high, the second terminal of the third transistor Q7 and the third terminal of the third transistor Q7 are turned on, the first terminal of the fifth transistor Q4 goes low, so that the second terminal of the fifth transistor Q4 and the third terminal of the fifth transistor Q4 are turned on, the first terminal of the first transistor Q2 goes high, so that the first transistor Q2 is turned off, and at this time, current cannot flow from the coil pull-in circuit 210 to the first terminal of the coil 140 through the third contact terminal JK 3.

In this process, the enable end of the coil control unit 130 outputs a low level or turns into a high resistance state, so that the power supply voltage reducing circuit 220 outputs a 2.6V on voltage, the 2.6V on voltage flows to the first end of the coil 140 through the seventh diode D1, a current for maintaining the pull-in state is provided to the coil 140, and the second channel is turned on, so that the coil 140 maintains a low power consumption and energy saving maintaining pull-in state.

(3) When the range of the dc input power supply voltage vin_pwr is greater than or equal to the third pull-in voltage and less than the fourth pull-in voltage, for example, the range of the dc input power supply voltage is [20,36 "), where the fourth pull-in voltage may be 36V or other voltage values greater than the third pull-in voltage, the pulse signal terminal of the coil control unit 130 outputs a high level pulse of 85ms, the second terminal of the second transistor Q6 and the third terminal of the second transistor Q6 in the coil pull-in circuit 210 are turned on, so that the first terminal of the third transistor Q7 becomes low level, and at this time, the voltage of the third terminal of the third transistor Q7 is high due to the dc input power supply voltage, so that the first terminal of the fifth transistor Q4 is high, the second terminal of the fifth transistor Q4 and the third terminal of the fifth transistor Q4 are turned off, and at this time the first terminal of the first transistor Q2 is low, so that the second terminal of the first transistor Q2 and the third terminal of the second transistor Q6 may be turned on, and the current may flow from the third terminal of the third transistor Q6 to the coil pull-in circuit 140 through the third terminal of the coil pull-in circuit 210.

After the pulse signal terminal of the coil control unit 130 outputs the high level pulse of 85ms, it becomes low level for 120ms, the second terminal of the second transistor Q6 and the third terminal of the second transistor Q6 in the coil pull-in circuit 210 are turned off, so that the first terminal of the third transistor Q7 becomes high level, the second terminal of the third transistor Q7 and the third terminal of the third transistor Q7 are turned on, the first terminal of the fifth transistor Q4 becomes low level, so that the second terminal of the fifth transistor Q4 and the third terminal of the fifth transistor Q4 are turned on, the first terminal of the first transistor Q2 becomes high level, so that the first transistor Q2 is turned off, and at this time, the current cannot flow from the coil pull-in circuit 210 to the first terminal of the coil 140 through the third contact terminal JK 3.

(4) When the coil 140 is in the on state, the control terminal of the coil control unit 130 outputs the first control signal of low level to make the first terminal of the sixth transistor Q3 be low level, the sixth transistor Q3 is turned off, the current cannot flow from the coil release circuit 230 to the second terminal of the coil 140, the current in the coil 140 is not looped, and the contactor immediately becomes in the release state when the dc input power supply voltage vin_pwr falls to the range of less than 5V. The coil release circuit 230 further includes a third diode D9 connected in parallel to two ends of the sixth transistor Q3, where the third diode D9 is an overvoltage protection diode, when the sixth transistor Q3 is turned off, a reverse electromotive force is generated in the coil 140, and the source and the drain of the sixth transistor Q3 are easy to break down, so that the third diode D9 can prevent the source and the drain of the sixth transistor Q3 from being broken down when the sixth transistor Q3 is turned off, thereby protecting the sixth transistor Q3.

The second transistor Q6 and the third transistor Q7 may be NPN transistors or N-type semiconductor field effect transistors, the fifth transistor Q4 may be a PNP transistor or a P-type semiconductor field effect transistor, the first transistor Q2 may be a P-type field effect transistor or a PNP transistor or a bipolar transistor, the sixth transistor Q3 may be an N-type field effect transistor or an NPN transistor or a bipolar transistor, the third contact terminal JK3 connects the first terminal of the coil 140 and the coil pull-in circuit 210, and the fourth contact terminal JK4 connects the second terminal of the coil 140 and the coil release circuit 230.

In summary, the coil control unit controls whether the coil 140 can be turned on and current flows through the range of the voltage value of the dc-on power supply voltage vin_pwr input in the control circuit of the low-voltage dc contactor, when the coil 140 is turned on, the third contact terminal JK3 and the fourth contact terminal JK4 are stably attracted, and when the coil 140 is not turned on, the third contact terminal JK3 and the fourth contact terminal JK4 are immediately released.

In addition, when the control circuit of the low voltage dc contactor is operated, the power supply access unit 110 is required to supply the input power to the respective circuits of the control circuit of the low voltage dc contactor. Next, a specific implementation manner of power supply of each circuit of the control circuit of the low voltage dc contactor according to the present application will be described in detail by taking fig. 6 as an example.

Referring to fig. 6, fig. 6 is a schematic diagram illustrating a power supply connection in a control circuit of a low voltage dc contactor according to an embodiment of the application.

In fig. 6, the second power supply terminal of the power supply access unit 110 is electrically connected to the third power supply terminal of the coil pull-in circuit 210, the third power supply terminal of the power supply access unit 110 is electrically connected to the third power supply terminal of the coil release circuit 230, and the fourth power supply terminal of the power supply step-down circuit 220 is electrically connected to the fifth power supply terminal of the coil control unit 130.

In fig. 6, the second power supply terminal of the power supply unit 110 is denoted as 2, the third power supply terminal of the coil pull-in circuit 210 is denoted as 3, the third power supply terminal of the power supply unit 110 is denoted as 3, the third power supply terminal of the coil release circuit 230 is denoted as 3, the fourth power supply terminal of the power supply step-down circuit 220 is denoted as 4, and the fifth power supply terminal of the coil control unit 130 is denoted as 5.

The power supply access unit 110 supplies power to the coil pull-in circuit 210, the coil release circuit 230, the power supply voltage reducing circuit 220, and the coil control unit 130 by connecting the coil pull-in circuit 210, the coil release circuit 230, the power supply voltage reducing circuit 220, and the coil control unit 130, respectively.

Wherein, the power supply access unit 110 is directly connected with the coil pull-in circuit 210, the coil release circuit 230 and the coil control unit 130, thereby providing the input voltage +24v for the coil pull-in circuit 210 and the coil release circuit 230. In addition, the power supply access unit 110 indirectly supplies power to the coil control unit 130 through the power supply voltage reducing circuit 220, the power supply access unit 110 inputs +24v of the input power supply of the power supply voltage reducing circuit 220, and can output stable 3.3V voltage through the power supply voltage reducing circuit 220, and then output the 3.3V voltage to the coil control unit 130, thereby providing the input power supply VDD for the coil control unit 130.

The power supply access unit 110 can supply power to other circuits in the control circuit of the low-voltage direct current contactor, and can also realize the functions of power supply input reverse connection prevention and power supply voltage detection. Next, a specific mode of the power supply access unit 110 in the control circuit of the low voltage dc contactor according to the present application will be described with reference to fig. 7.

Referring to fig. 7, fig. 7 is a schematic diagram illustrating a structure of a power access unit 110 in a control circuit of a low voltage dc contactor according to an embodiment of the application. In fig. 7, the power access unit 110 includes: an anti-reverse connection circuit 310 and a power supply detection circuit 320.

The first end of the anti-reverse connection circuit 310 is electrically connected to the first end of the power supply detection circuit 320, the first end of the power supply voltage reduction circuit 220, and the first end of the coil pull-in circuit 210, the second end of the power supply detection circuit 320 is electrically connected to the first input end of the control unit 130, and the second end of the anti-reverse connection circuit 310 is electrically connected to the third end of the release circuit 230.

In fig. 7, a first end of the anti-reverse connection circuit 310 is denoted as 1, a second end of the anti-reverse connection circuit 310 is denoted as 2, a third end of the anti-reverse connection circuit 310 is denoted as 3, a first end of the power supply detection circuit 320 is denoted as 1, and a second end of the power supply detection circuit 320 is denoted as 2.

The power supply access unit 110 in the control circuit of the low-voltage dc contactor may access the dc input power supply voltage through the reverse connection preventing circuit 310 and output the dc input power supply voltage to the coil pull-in circuit 210, the coil release circuit 230, and the power supply voltage reducing circuit 220. The voltage value of the dc input power may also be detected by the power detection circuit 320, to generate the first voltage Uadc, and to transmit the generated first voltage Uadc to the coil control unit 130.

In addition, the reverse connection preventing circuit 310 can perform normal operation when the positive and negative poles of the power supply are connected reversely, so that the positive and negative poles of the power supply do not need to be distinguished when the control circuit of the low-voltage direct current contactor is connected to the power supply.

Next, a specific circuit implementation of the power supply access unit 110 in the control circuit of the low voltage dc contactor according to the present application will be described in detail with reference to fig. 8.

Referring to fig. 8, fig. 8 is a schematic circuit diagram of a power access unit 110 in a control circuit of a low voltage dc contactor according to an embodiment of the application. In fig. 8, the reverse connection preventing circuit 310 includes: the rectifier module DB1, a ninth diode D3, a tenth diode D4, a twenty-first resistor R2 and a tenth capacitor.

The second end of the rectifying module DB1 is electrically connected to the input power supply VDD, the first end of the twenty-first resistor R2 is electrically connected to the thirty-sixth connection point, the thirty-sixth connection point is disposed between the second end of the rectifying module DB1 and the dc input power supply voltage, the first end of the ninth diode D3 is electrically connected to the thirty-seventh connection point, the thirty-seventh connection point is disposed between the second end of the rectifying module DB1 and the thirty-sixth connection point, the second end of the twelfth diode D4 is electrically connected to the third end of the coil release circuit 230, the second end of the ninth diode D3 is electrically connected to the thirty-eighth connection point, the thirty-eighth connection point is disposed between the second end of the twelfth diode D4 and the third end of the coil release circuit 230, the second end of the rectifying module DB1 is electrically connected to the thirty-ninth connection point, the first end of the tenth diode D4 is electrically connected to the fortieth connection point, the fortieth connection point is electrically connected to the fortieth connection point is disposed between the first end of the rectifying module DB1 and the thirty-ninth connection point, the fortieth connection point is electrically connected to the fortieth end of the fourth end of the rectifying module DB1, the circuit point is electrically connected to the fortieth end of the fourth end of the rectifier module 210 is electrically connected to the fortieth end of the fourth diode D1, and the fortieth connection point is electrically connected to the fortieth end of the fortieth circuit point of the capacitor 220.

In fig. 8, a thirty-sixth connection point is connected to the first contact terminal JK1, a thirty-ninth connection point is connected to the second contact terminal JK2, and a forty-fourth connection point is connected to the third terminal of the coil pull-in circuit 210 and the third terminal of the power supply voltage reducing circuit 220 by a voltage of +24v. TP1, TP2 and TP3 are three test points of the anti-reverse connection circuit 310 in the power supply access unit 110, and the anti-reverse connection circuit 310 can be debugged and tested at the three test points.

The rectifying module DB1 may convert an input voltage into an output dc voltage, and may further implement a reverse connection preventing function of the power supply, and when polarities of the positive and negative poles of the input power supply are connected in error, the rectifying module DB1 may control a current to be input through the positive pole and thus enter the reverse connection preventing circuit 310, and prevent the current from being input through the negative pole and thus enter the reverse connection preventing circuit 310.

In summary, the anti-reverse connection circuit 310 implements an anti-reverse connection function for the dc input power through the rectifying module DB 1.

In fig. 8, the power supply detection circuit 320 includes: twenty-second resistor R5, twenty-third resistor R6, twenty-fourth resistor R7, eleventh capacitor and clamping module D5.

The first end of the twenty-second resistor R5 is electrically connected to the forty-third connection point, the second end of the twenty-second resistor R5 is electrically connected to the first end of the twenty-third resistor R6, the second end of the twenty-third resistor R6 is electrically connected to the first end of the twenty-fourth resistor R7, the second end of the twenty-fourth resistor R7 is grounded, the first end of the clamping module D5 is grounded, the fourth end of the clamping module D5 is electrically connected to the forty-fourth connection point, the forty-fourth connection point is disposed between the second end of the twenty-third resistor R6 and the first end of the twenty-fourth resistor R7, the second end of the clamping module D5 is connected to the dc input power supply voltage, the third end of the clamping module D5 is electrically connected to the first input end of the coil control unit 130, the first end of the eleventh capacitor is electrically connected to the forty-fifth connection point, and the second end of the eleventh capacitor is grounded.

In fig. 8, the first end of the clamping module D5 is denoted as 1, the second end of the clamping module D5 is denoted as 2, the third end of the clamping module D5 is denoted as 3, the fourth end of the clamping module D5 is denoted as 4, the first end of the rectifying module DB1 is denoted as 1, the second end of the rectifying module DB1 is denoted as 2, the third end of the rectifying module DB1 is denoted as 3, the fourth end of the rectifying module DB1 is denoted as 4, and the forty-fifth connection point outputs the first voltage Uadc to the coil control unit 130.

The power supply detection circuit 320 detects a voltage value between the twenty-third resistor R6 and the twenty-fourth resistor R7 by connecting the twenty-second resistor R5, the twenty-third resistor R6, and the twenty-fourth resistor R7 in series, and transmits the voltage value to the coil control unit 220.

The clamping module D5 can clamp the voltage, ensures that the input voltage VDD is limited in a safe range when exceeding a set value according to the regulated voltage within the set range, and protects subsequent circuits or devices from the excessive voltage.

In summary, the power supply detection circuit 320 performs voltage detection on the dc input power supply voltage, and inputs the dc input power supply voltage to the coil control unit 130 in the form of the first voltage Uadc.

Finally, it should be noted that: the above embodiments are merely specific embodiments of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions within the technical scope of the present application should be covered by the scope of the present application. Therefore, the protection scope of the application is subject to the protection scope of the claims.

Claims

1. A control circuit for a low voltage dc contactor, comprising: the device comprises a coil control unit, a power supply access unit and a coil action unit;

The first end of the power supply access unit is electrically connected with the first input end of the coil control unit; the second end of the coil control unit is electrically connected with the first end of the coil action unit, the first end of the coil action unit is electrically connected with the first end of the coil, the second end of the coil is electrically connected with the third end of the coil action unit, the third end of the coil action unit is electrically connected with the fourth control end of the coil control unit, the third end of the coil control unit is electrically connected with the second end of the coil action unit, and the second end of the coil action unit is electrically connected with the first end of the coil; a first channel is formed among the second end of the coil control unit, the first end of the coil action unit, the first end of the coil, the second end of the coil, the third end of the coil action unit and the fourth control end of the coil control unit; and a second channel is formed among the third end of the coil control unit, the second end of the coil action unit, the first end of the coil, the second end of the coil, the third end of the coil action unit and the fourth control end of the coil control unit.

2. The control circuit according to claim 1, wherein the coil action unit includes: a power supply voltage reducing circuit, a coil attracting circuit and a coil releasing circuit;

The first end of the power supply access unit is electrically connected with the first input end of the coil control unit, the second end of the coil control unit is electrically connected with the first end of the coil pull-in circuit, the second end of the coil pull-in circuit is electrically connected with the first end of the coil release circuit, the second end of the coil release circuit is electrically connected with the fourth control end of the coil control unit, the third end of the coil control unit is electrically connected with the first end of the power supply voltage reduction circuit, and the second end of the power supply voltage reduction circuit is electrically connected with the first end of the coil; the second end of the coil control unit, the first end of the coil pull-in circuit, the second end of the coil pull-in circuit, the first end of the coil, the second end of the coil, the first end of the coil release circuit, the second end of the coil release circuit and the fourth control end of the coil control unit form the first channel; the third end of the coil control unit, the first end of the power supply voltage reducing circuit, the second end of the power supply voltage reducing circuit, the first end of the coil, the second end of the coil, the first end of the coil release circuit, the second end of the coil release circuit and the fourth control end of the coil control unit form the second channel;

The power supply access unit is used for accessing direct current input power supply voltage and sending first voltage to the coil control unit, wherein the first voltage is used for representing the change condition of the direct current input power supply voltage;

The coil control unit is used for transmitting a first control signal to the coil release circuit when the first voltage represents that the direct current input power supply voltage is smaller than a second pull-in voltage so as to release the coil; wherein the first control signal is used for closing the first channel and the second channel;

The coil control unit is further configured to send a first enable signal to the power supply voltage reduction circuit when the first voltage indicates that the dc input power supply voltage is greater than a second pull-in voltage and less than the first pull-in voltage, so as to release the coil; the first enabling signal is used for controlling the power supply voltage reducing circuit to not output a conducting voltage and a conducting current so as to enable the second channel to be closed, and the coil sucking circuit is in an off state so as to enable the first channel to be closed;

The coil control unit is further configured to send a pulse signal to the coil pull-in circuit, transmit a second control signal to the coil release circuit, and send a second enable signal to the power supply voltage-down circuit to pull-in the coil when the first voltage indicates that the dc input power supply voltage is greater than or equal to a first pull-in voltage; when the level of the pulse signal is high, the pulse signal and the second control signal are used for controlling the coil pull-in circuit and the coil release circuit to be conducted so as to conduct the first channel, and the power supply voltage reducing circuit is in an off state so as to close the second channel; when the level of the pulse signal is low, the second enabling signal is used for controlling the power supply voltage-reducing circuit to output a conducting voltage and a conducting current, the second control signal is used for controlling the coil releasing circuit to be conducted so as to conduct the second channel, and the coil sucking circuit is in an off state so as to close the first channel.

3. The control circuit of claim 2, wherein the coil pull-in circuit comprises: a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a first diode, a second diode, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a first capacitor, and a second capacitor;

The first end of the second capacitor is electrically connected to the second end of the power supply access unit, the second end of the second capacitor is grounded, the first end of the sixth resistor is electrically connected to the second end of the coil control unit, the second end of the sixth resistor is electrically connected to the first end of the second transistor, the first connection point is electrically connected to the first connection point of the seventh resistor, the first connection point is disposed between the second end of the sixth resistor and the first end of the third transistor, the second end of the second transistor is electrically connected to the third connection point, the third end of the third resistor is electrically connected to the second connection point, the second end of the seventh resistor is electrically connected to the second connection point, the first end of the fourth resistor is electrically connected to the third connection point, the third end of the fifth resistor is electrically connected to the fourth connection point, the third end of the fourth resistor is disposed between the third connection point of the third resistor and the fourth connection point, the third end of the fourth resistor is electrically connected to the fourth connection point, the third end of the fourth resistor is electrically connected to the fourth connection point of the third resistor is disposed between the third end of the third resistor, and the fourth connection point is electrically connected to the third connection point of the third resistor is electrically connected to the third connection point, a seventh connection point is electrically connected to an eighth connection point, the seventh connection point is disposed between the second end of the second resistor and the third end of the third transistor, the eighth connection point is disposed between the third end of the fourth transistor and the second end of the fifth resistor, the first end of the fifth resistor is electrically connected to the first end of the fifth transistor, the second end of the fifth transistor is electrically connected to a ninth connection point, the ninth connection point is disposed between the sixth connection point and the first end of the second resistor, the third end of the fifth transistor is electrically connected to the second end of the third resistor, the first end of the first diode is electrically connected to a tenth connection point, the tenth connection point is disposed between the ninth connection point and the second end of the fifth transistor, the second end of the first diode is electrically connected to an eleventh connection point, the eleventh connection point is disposed between the third end of the fifth transistor, the third connection point is electrically connected to the second end of the third resistor, the twelfth connection point is disposed between the first end of the fifth resistor, the fourth connection point is electrically connected to the fifth connection point, the fourth connection point is disposed between the fourth connection point and the fifth connection point, the fourth connection point is electrically connected to the thirteenth connection point, the fifteenth connection point is arranged between the eleventh connection point and the third end of the fifth transistor, the second end of the fourth resistor is grounded, the second end of the eighth resistor is electrically connected with the first end of the ninth resistor, the second end of the ninth resistor is grounded, the first end of the second diode is electrically connected with the sixteenth connection point, the sixteenth connection point is arranged between the second end of the first transistor and the first end of the coil, the second end of the second diode is electrically connected with the seventeenth connection point, and the seventeenth connection point is arranged between the second end of the eighth resistor and the first end of the ninth resistor.

4. The control circuit of claim 2, wherein the coil release circuit comprises: a sixth transistor, a seventh transistor, a third diode, a fourth diode, a fifth diode, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, and a third capacitor;

The second end of the fourteenth resistor is electrically connected to the fourth control end of the coil control unit, the first end of the fourteenth resistor is electrically connected to the first end of the seventh transistor, the second end of the seventh transistor is grounded, the third end of the seventh transistor is electrically connected to the second end of the thirteenth resistor, the first end of the thirteenth resistor is electrically connected to the second end of the eleventh resistor, the first end of the twelfth resistor is electrically connected to an eighteenth connection point, the eighteenth connection point is disposed between the second end of the eleventh resistor and the first end of the thirteenth resistor, the second end of the twelfth resistor is electrically connected to the third end of the power supply access unit, the first end of the eleventh resistor is electrically connected to the second end of the fifth diode, the first end of the fifth diode is electrically connected to the first end of the sixth transistor, the second end of the sixth transistor is electrically connected to the second end of the coil, the third end of the sixth transistor is electrically connected to the twenty-third connection point, the twenty-third connection point is electrically connected to the twenty-eighth connection point, the twenty-third connection point is electrically connected to the twenty-third end of the twenty-fifth transistor, the twenty-third connection point is electrically connected to the twenty-third connection point is disposed between the twenty-third end of the twenty-fifth resistor and the twenty-fifth connection point, the twenty-third connection point is electrically connected to the twenty-third connection point is disposed between the twenty-third end of the twenty third connection point and the twenty connection point is electrically connected to the twenty connection point of the twenty connection point, the twenty-third connection point is disposed between the twenty-third connection point and the first end of the fifth diode, the second end of the tenth resistor is electrically connected to the twenty-second connection point, the twenty-second connection point is disposed between the twenty-second connection point and the first end of the fourth diode, the first end of the third capacitor is electrically connected to the twenty-fifth connection point, the twenty-fifth connection point is disposed between the twenty-third connection point and the first end of the fifth diode, the second end of the third capacitor is electrically connected to the twenty-fourth connection point, and the twenty-fourth connection point is disposed between the twenty-second connection point and the second end of the tenth resistor.

5. The control circuit of claim 2, wherein the power supply step-down circuit comprises: an eighth transistor, a sixth diode, a seventh diode, an eighth diode, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a twentieth resistor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a seventh capacitor, an eighth capacitor, a ninth capacitor, a first inductor, a first buck module, and a second buck module;

The first end of the first voltage dropping module and the first end of the fourth capacitor are electrically connected with the second end of the power supply access unit, the second end of the fourth capacitor is grounded, the fourth end of the first voltage dropping module and the first end of the fifteenth resistor are electrically connected with the third end of the coil control unit, the second end of the fifteenth resistor is grounded, the fifth end of the first voltage dropping module, the sixth end of the first voltage dropping module, the seventh end of the first voltage dropping module, the eighth end of the first voltage dropping module and the ninth end of the first voltage dropping module are grounded, the second end of the first voltage dropping module is electrically connected with the first end of the first inductor, the second end of the first inductor is electrically connected with the first end of the seventh diode, the second end of the seventh diode is electrically connected with the first end of the coil, the second end of the sixth diode is electrically connected with a twenty-fourth connection point, the twenty-fourth connection point is arranged between the second end of the first voltage dropping module and the first end of the first inductor, the first end of the sixth diode is grounded, the first end of the sixteenth resistor is electrically connected with a twenty-fifth connection point, the twenty-fifth connection point is arranged between the second end of the first inductor and the first end of the seventh diode, the second end of the sixteenth resistor is electrically connected with the first end of the seventeenth resistor, the second end of the seventeenth resistor is grounded, the third end of the first voltage dropping module is electrically connected with a twenty-sixth connection point, the twenty-sixth connection point is arranged between the second end of the sixteenth resistor and the first end of the seventeenth resistor, the first end of the fifth capacitor is electrically connected with a twenty-seventh connection point, the twenty-seventh connection point is arranged between the twenty-fifth connection point and the first end of the seventh diode, the first end of the sixth capacitor is electrically connected with the twenty-eighth connection point, the twenty-eighth connection point is arranged between the twenty-seventh connection point and the first end of the seventh diode, and the second end of the sixth capacitor and the second end of the fifth capacitor are grounded; the first end of the eighteenth resistor and the first end of the nineteenth resistor are both electrically connected to the second end of the power supply access unit, the second end of the eighteenth resistor is electrically connected to the second end of the eighth transistor, the first end of the eighth transistor is electrically connected to the first end of the eighth diode, the second end of the eighth diode is grounded, the second end of the nineteenth resistor is electrically connected to a twenty-ninth connection point, the twenty-ninth connection point is disposed between the first end of the eighth transistor and the first end of the eighth diode, the third end of the eighth transistor is electrically connected to the first end of the twenty-third resistor, the second end of the twenty-eighth resistor is electrically connected to a thirty-third connection point of the twenty-third voltage reduction module, the thirty-third connection point is disposed between the second end of the twenty-eighth resistor and the third end of the thirty voltage reduction module, the first end of the eighth capacitor is electrically connected to a thirty-third connection point, the thirty-third connection point is disposed between the thirty-third connection point and the thirty-third connection point, the thirty-third connection point is electrically connected to the thirty-fourth connection point, the third connection point is disposed between the thirty-third connection point and the thirty-third connection point, the third connection point is electrically connected to the thirty-third connection point is electrically connected to the third connection point, the third connection point is disposed between the third end of the thirty-third capacitor and the thirty-third connection point is electrically connected to the third connection point, the second end of the second voltage reduction module and the fourth end of the second voltage reduction module are electrically connected with a thirty-fifth connection point, and the thirty-fifth connection point is arranged between the first end of the ninth capacitor and the fifth end of the coil control unit.

6. The control circuit of claim 2, wherein the power access unit comprises: an anti-reverse connection circuit and a power supply detection circuit;

the first end of the reverse connection preventing circuit is electrically connected with the first end of the power supply detecting circuit, the first end of the power supply voltage reducing circuit and the first end of the coil attracting circuit, the second end of the power supply detecting circuit is electrically connected with the first input end of the coil control unit, and the second end of the reverse connection preventing circuit is electrically connected with the third end of the coil releasing circuit;

The reverse connection preventing circuit is used for connecting the direct current input power supply voltage and outputting the direct current input power supply voltage to the coil pull-in circuit, the coil release circuit and the power supply voltage reducing circuit;

The power supply detection circuit is used for detecting the direct current input power supply voltage input from the anti-reverse connection circuit, generating the first voltage and sending the first voltage to the coil control unit.

7. The control circuit of claim 6, wherein the anti-reverse circuit comprises: the rectifier module, the ninth diode, the twelfth diode, the twenty-first resistor and the tenth capacitor;

The second end of the rectifier module is electrically connected with an input power supply, the first end of the twenty-first resistor is electrically connected with a thirty-sixth connection point, the thirty-sixth connection point is arranged between the second end of the rectifier module and the direct-current input power supply voltage, the first end of the ninth diode is electrically connected with a thirty-seventh connection point, the thirty-seventh connection point is arranged between the second end of the rectifier module and the thirty-sixth connection point, the second end of the tenth diode is electrically connected with a third end of the coil release circuit, the second end of the ninth diode is electrically connected with a thirty-eighth connection point, the thirty-eighth connection point is arranged between the second end of the tenth diode and the third end of the coil release circuit, the second end of the rectifier module is electrically connected with a thirty-ninth connection point, the third end of the fourth diode is electrically connected with a thirty-ninth connection point, the fourth end of the fourth diode is electrically connected with a fortieth connection point, the fourth connection point is electrically connected with a fortieth connection point, the fortieth connection point is arranged between the thirty-fourth end of the rectifier module and the fourth end of the rectifier module, the fortieth connection point is electrically connected with the fortieth connection point is connected with the fortieth circuit, the fortieth end of the fourth connection point is electrically connected with the fortieth connection point, the fourth connection point is connected with the fortieth connection point is.

8. The control circuit of claim 7, wherein the power supply detection circuit comprises: twenty-second resistor, twenty-third resistor, twenty-fourth resistor, eleventh capacitor and clamping module;

The first end of the twenty-second resistor is electrically connected with the forty-third connection point, the second end of the twenty-second resistor is electrically connected with the first end of the twenty-third resistor, the second end of the twenty-third resistor is electrically connected with the first end of the twenty-fourth resistor, the second end of the twenty-fourth resistor is grounded, the first end of the clamping module is electrically connected with the forty-fourth connection point, the forty-fourth connection point is arranged between the second end of the twenty-third resistor and the first end of the twenty-fourth resistor, the second end of the clamping module is connected with a direct current input power supply voltage, the third end of the clamping module is electrically connected with the first input end of the coil control unit, the first end of the eleventh capacitor is electrically connected with the forty-fifth connection point, the forty-fifth connection point is arranged between the first input end of the coil control unit and the third end of the clamping module, and the second end of the eleventh capacitor is grounded.

9. The control circuit according to any one of claims 2 to 8, wherein a pulse width of the pulse signal when the dc input power supply voltage is greater than or equal to the first pull-in voltage and less than the third pull-in voltage is the first pulse width;

The pulse width of the pulse signal is the second pulse width when the direct current input power supply voltage is larger than or equal to the third pull-in voltage;

the first pulse width is greater than the second pulse width.

10. A low voltage dc contactor, comprising: coil and control circuit for a low voltage dc contactor according to any of claims 1-9.