Automatic power-off circuit for equipment

Abstract

The embodiment of the utility model provides an automatic power-off circuit for equipment. The automatic power-off circuit comprises a contactor, electric equipment, an equipment controller, a control unit, a normally-closed relay, a silicon controlled rectifier, an optocoupler and an AC-DC power supply, the input end of the contactor is communicated with the input end of the AC-DC power supply, the output end of the AC-DC power supply is respectively communicated with the normally-closed relay and the silicon controlled rectifier, the normally-closed relay is electrically connected with the contactor, the silicon controlled rectifier is electrically connected with the control unit through the optocoupler, and the normally-closed contactor is respectively and electrically connected with the electric equipment and the control unit. And the electric equipment is electrically connected with the control unit through the equipment controller. In this way, when power failure is needed, the silicon controlled rectifier is controlled to be opened, the relay is switched off, the contactor is powered off accordingly, one path of power supply of the silicon controlled rectifier is connected to the front end of the contactor and still has power, the silicon controlled rectifier is kept in the conducting state, power failure of electric equipment is achieved, and therefore the stability and reliability of automatic power failure are improved, and safety is improved.

Description

Technical Field

[0001] The present application relates to a circuit for controlling power supply of a device, and in particular to a circuit for automatically powering off a device. Background Art

[0002] It is inevitable that the equipment will encounter faults or external disasters during operation. When a fault occurs, in order to avoid secondary hazards such as fire, electric shock, etc., the equipment must be powered off in time. Sometimes it is also necessary to power off the microcontroller control part.

[0003] In the single-chip microcomputer application system, the IO port is used to realize the self-shutdown (complete shutdown) function. Generally, an IO port of the single-chip microcomputer is used to control an electronic switch. However, when the electronic switch turns off the power supply, due to the presence of capacitors in the power supply, the voltage of the single-chip microcomputer system does not immediately become 0, but slowly becomes lower. When the voltage drops to a certain voltage, the single-chip microcomputer will enter a reset state, or a program runaway state, or an uncertain state. At this time, the IO port of the single-chip microcomputer that controls the power off may also have a level jump, which will cause the electronic switch to be turned on again, and the power off fails, posing a safety hazard. Utility Model Content

[0004] In view of this, an embodiment of the present application provides a circuit for automatically powering off a device to overcome the technical problem of incomplete power-off of electronic switches in the prior art, thereby improving safety.

[0005] According to an embodiment of the present application, a circuit for automatically powering off a device is provided, comprising:

[0006] Contactors, electrical equipment, equipment controllers, control units, normally closed relays, thyristors, optocouplers and AC-DC power supplies;

[0007] The input end of the contactor is connected to the input end of the AC-DC power supply, and the output end of the AC-DC power supply is connected to the normally closed relay and the thyristor respectively. The normally closed relay is electrically connected to the contactor, and the thyristor is electrically connected to the control unit through an optocoupler. The normally closed contactor is electrically connected to the electrical equipment and the control unit respectively, and the electrical equipment is electrically connected to the control unit through the equipment controller.

[0008] In some embodiments, it also includes:

[0009] The AC power supply, the input end of the contactor and the input end of the AC-DC power supply are connected to the AC power supply.

[0010] In some embodiments, it also includes:

[0011] A voltage conversion module is provided between the contactor and the control unit and is used for converting the alternating current output by the contactor into direct current for powering the control unit.

[0012] In some embodiments, the contactor includes multiple input terminals and output terminals corresponding to the input terminals, the input terminals are electrically connected to the AC power supply, the output terminals are electrically connected to the electrical equipment, and the coil terminals of the contactor are connected to the phase line of the AC power supply.

[0013] In some embodiments, a transistor is arranged between the control unit and the optocoupler, a first protection resistor is arranged between the control unit and the base of the transistor, the emitter of the transistor is grounded, a second protection resistor is arranged between the base and the emitter, and the collector of the transistor is electrically connected to the input end of the optocoupler through the third protection resistor.

[0014] In some embodiments, the output end of the optocoupler is grounded through a fourth protection resistor, and is electrically connected to the thyristor through a fifth protection resistor.

[0015] The circuit for automatically powering off a device in the embodiment of the present application adopts a contactor as an action switch, cooperates with the switch characteristics of the thyristor, and adopts a dual switch power supply mode, one way is for powering the thyristor, connected at the front end of the contactor, and one way is for powering the control circuit, connected at the back end of the contactor. When the power needs to be cut off, the control opens the thyristor, the relay is disconnected, and the contactor is powered off, but the power supply of the thyristor is connected to the front end of the contactor, and there is still electricity, which maintains the thyristor in the conducting state, and realizes the power off of the electrical equipment, thereby improving the stability and reliability of automatic power off, and then improving safety.

[0016] It should be understood that the contents described in the utility model content section are not intended to limit the key or important features of the embodiments of the present application, nor are they intended to limit the scope of the present application. Other features of the present application will become easy to understand through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and other features, advantages and aspects of the embodiments of the present application will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. The accompanying drawings are used to better understand the present solution and do not constitute a limitation of the present application. In the accompanying drawings, the same or similar reference numerals represent the same or similar elements, wherein:

[0018] Figure 1 A schematic diagram showing the structure of a circuit for automatically powering off a device according to an embodiment of the present application is shown;

[0019] Figure 2 A circuit diagram of a circuit for automatically powering off a device according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0021] In addition, the term "and / or" in this article is only a description of the association relationship between the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0022] The circuit for automatically powering off the equipment in the embodiment of the present application adopts a contactor as an action switch, cooperates with the switch characteristics of the thyristor, and adopts a dual switch power supply mode, one way is to power the thyristor, connected at the front end of the contactor, and one way is to power the control circuit, connected at the back end of the contactor. When the power needs to be cut off, the control opens the thyristor, the relay is disconnected, and the contactor is powered off, but the power supply of the thyristor is connected to the front end of the contactor, and there is still electricity, which maintains the thyristor in the conducting state, and realizes the power off of the electrical equipment, thereby improving the stability and reliability of automatic power off, and then improving safety.

[0023] Specifically, Figure 1 , which is a schematic diagram of the structure of a circuit for automatically powering off a device according to an embodiment of the present application. In this embodiment, the circuit for automatically powering off a device includes:

[0024] Contactor, electrical equipment, equipment controller, control unit, normally closed relay, thyristor, optocoupler and AC-DC power supply. The input end of the contactor is connected to the input end of the AC-DC power supply, the output end of the AC-DC power supply is respectively connected to the normally closed relay and the thyristor, the normally closed relay is electrically connected to the contactor, the thyristor is electrically connected to the control unit through the optocoupler, the normally closed contactor is electrically connected to the electrical equipment and the control unit respectively, and the electrical equipment is electrically connected to the control unit through the equipment controller.

[0025] In this embodiment, it also includes: an AC power supply, and the input end of the contactor and the input end of the AC-DC power supply are connected to the AC power supply. Specifically, the AC power supply can be connected to the contactor and the AC-DC power supply by a main switch, and the two wires (phase line and neutral line) drawn from the main switch are used to power the contactor and the AC-DC power supply. Among them, the two wires drawn from the contactor are respectively connected to the power-consuming device and the control unit, and are used to power the power-consuming device and the control unit. In this embodiment, the power-consuming device can be an AC power-consuming device, and the control unit can be a DC control unit. Therefore, a voltage conversion module (such as the AC-DC power supply shown in the figure) can also be set between the contactor and the control unit, and the AC power is converted into DC power by the voltage conversion module to power the control unit. The control unit in this embodiment can be a single-chip microcomputer. The power-consuming device is electrically connected to the control unit through the device controller, and the control unit can control the power-consuming device through the device controller, such as sending a control instruction, which can be a digital signal or an electrical signal, which is not listed here one by one. At the same time, the control unit can also be connected to a fault signal generator and a human-computer interaction terminal, wherein the fault signal generator is used to send a fault signal to the control unit when a fault occurs in the electrical device, and the fault signal can be a wireless signal or a wired signal. The user can send a control instruction to the control unit through the human-computer interaction terminal to control the electrical device.

[0026] The output end of the AC-DC power supply is connected to the normally closed relay and the thyristor respectively, and a two-wire connection method is also adopted. The normally closed relay is in a normally closed state, that is, a conducting state, and is electrically connected to the contactor. The thyristor is connected to the control unit through an optocoupler.

[0027] Under normal conditions, the contactor is in the on state, the normally closed relay is in the normally closed state, the circuit is energized normally, and the electrical equipment operates normally. When the electrical equipment fails and needs to be powered off, the control unit reduces or removes the forward voltage between the anode and cathode of the thyristor through the optical coupler, so that the anode current is less than the minimum holding current, the thyristor is powered off, the normally closed relay is disconnected, and then the contactor is powered off, stopping powering the electrical equipment.

[0028] There are two conditions for the conduction of thyristor: first, a positive voltage must be applied between the anode and cathode of the thyristor, and second, a positive voltage must be applied to the control electrode. The above two conditions must be met at the same time for the thyristor to be in the conduction state. In addition, once the thyristor is turned on, even if the control electrode voltage is reduced or removed, the thyristor will still be turned on.

[0029] Thyristor turn-off condition: reduce or remove the forward voltage between the anode and cathode of the thyristor so that the anode current is less than the minimum holding current.

[0030] The circuit for automatically powering off the equipment in the embodiment of the present application is to eliminate the possibility of power-off failure caused by the instability of the single-chip system during the power-off process, and to ensure that the system can only be restarted with the participation of the operation and maintenance personnel. By utilizing the switching characteristics of the thyristor, once turned on, it is not affected by the jump of the IO level of the single-chip control terminal, effectively ensuring that the equipment automatically powers off. By using a contactor as an action switch, cooperating with the switching characteristics of the thyristor, and adopting a dual-switch power supply method, the stability and reliability of automatic power-off are improved, thereby improving safety.

[0031] like Figure 2 , which is a circuit diagram of a circuit for automatically powering off a device according to an embodiment of the present application. In this embodiment, the contactor includes a plurality of input terminals and output terminals corresponding to the input terminals, the input terminals are electrically connected to an AC power supply, the output terminals are electrically connected to an electrical device, and the coil terminal of the contactor is connected to a phase line of the AC power supply.

[0032] A transistor is arranged between the control unit and the optocoupler, a first protection resistor R4 is arranged between the control unit and the base of the transistor, the emitter of the transistor is grounded, a second protection resistor R5 is arranged between the base and the emitter, and the collector of the transistor is electrically connected to the input end of the optocoupler through the third protection resistor R1.

[0033] The output end of the optical coupler is grounded through the fourth protection resistor R3, and is electrically connected to the thyristor through the fifth protection resistor R2.

[0034] This embodiment can achieve technical effects similar to those of the above embodiments, which will not be repeated here.

[0035] The above specific implementations do not constitute a limitation on the protection scope of this application. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of this application should be included in the protection scope of this application.

Claims

1. A circuit for automatically powering off a device, characterized in that: include: Contactors, electrical equipment, equipment controllers, control units, normally closed relays, thyristors, optocouplers and AC-DC power supplies; The input end of the contactor is connected to the input end of the AC-DC power supply, and the output end of the AC-DC power supply is connected to the normally closed relay and the thyristor respectively. The normally closed relay is electrically connected to the contactor, and the thyristor is electrically connected to the control unit through an optocoupler. The normally closed contactor is electrically connected to the electrical equipment and the control unit respectively, and the electrical equipment is electrically connected to the control unit through the equipment controller.

2. The circuit for automatically shutting off the power of the equipment according to claim 1, characterized in that: Also includes: The AC power supply, the input end of the contactor and the input end of the AC-DC power supply are connected to the AC power supply.

3. The circuit for automatically shutting off the power of the equipment according to claim 2, characterized in that: Also includes: A voltage conversion module is provided between the contactor and the control unit and is used for converting the alternating current output by the contactor into direct current for powering the control unit.

4. The circuit for automatically shutting off the power of the equipment according to claim 3, characterized in that: The contactor includes a plurality of input terminals and output terminals corresponding to the input terminals. The input terminals are electrically connected to the AC power supply, the output terminals are electrically connected to the electrical equipment, and the coil terminals of the contactor are connected to the phase line of the AC power supply.

5. The circuit for automatically shutting off the equipment according to claim 4, characterized in that: A transistor is arranged between the control unit and the optical coupler, a first protection resistor is arranged between the control unit and the base of the transistor, the emitter of the transistor is grounded, a second protection resistor is arranged between the base and the emitter, and the collector of the transistor is electrically connected to the input end of the optical coupler through the third protection resistor.

6. The circuit for automatically shutting off the power of the equipment according to claim 5, characterized in that: The output end of the optical coupler is grounded through a fourth protection resistor, and is electrically connected to the thyristor through a fifth protection resistor.

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