On-off state detection circuit and contactor

Abstract

The application discloses a kind of on-off state detection circuit and contactor, belong to low-voltage electrical apparatus technical field, the on-off state detection circuit includes with the dynamic contact of contactor connection follow-up module, and with the detection module of follow-up module corresponding arrangement;Wherein, in the process that dynamic contact drives follow-up module movement, detection module detects the on-off state of contactor according to the position of follow-up module.This application is by setting follow-up module to follow the dynamic contact movement of contactor, so that detection module can detect the on-off state of contactor according to the position of follow-up module.Such, as long as contactor produces action, detection module can detect the position change of follow-up module, to realize directly according to the action condition of dynamic contact to detect the on-off state of contactor, will not appear state misjudgment situation, improve the reliability of resulting contactor's on-off state detection.

Description

Technical Field

[0001] This application relates to the field of low-voltage electrical technology, and in particular to a circuit and contactor for detecting on / off states. Background Technology

[0002] In related technologies, the on / off state of a contactor can be detected by applying a small current to a mechanical NC contact (Normally Closed Contact) and using a PLC (Programmable Logic Controller) to detect the current signal of the NC contact.

[0003] However, as the NC contacts are used for a long time, their surfaces gradually wear and oxidize, increasing the contact resistance. This makes it impossible for a small current to overcome the contact resistance. At this point, even if the contactor has actually operated, the PLC cannot effectively detect the current signal, resulting in misjudgment of the status and low reliability of the contactor's on / off status detection. Utility Model Content

[0004] The main objective of this application is to provide an on / off state detection circuit and contactor, which aims to at least partially solve the aforementioned technical problems.

[0005] To achieve the above objectives, in a first aspect, a circuit for detecting on / off states is provided, including a follower module connected to the moving contact of a contactor, and a detection module corresponding to the follower module; wherein, during the process of the moving contact driving the follower module to move, the detection module detects the on / off state of the contactor according to the position of the follower module.

[0006] In some embodiments, the detection module includes an optocoupler and a state detection unit. The follow-up module is located between the light-emitting diode and the phototransistor of the optocoupler. The light-emitting diode includes a positive terminal connected to the power supply and a negative terminal grounded. The phototransistor includes a collector and an emitter connected to the state detection unit. When the follow-up module follows the moving contact to different positions, it causes the optocoupler to switch between being turned on or off and outputs the corresponding position signal. The status detection unit determines the on / off state based on the position signal output by the follow-up module.

[0007] In some embodiments, the state detection unit includes a switching device, a first resistor, a second resistor, and a controller; The switching device includes an input terminal connected to the first end of the first resistor, a control terminal connected to the collector of the phototransistor and the first end of the second resistor respectively, and a grounded output terminal. The second ends of the first resistor and the second ends of the second resistor are connected to a common contact point and then connected to the controller. The emitter of the phototransistor is grounded.

[0008] In some embodiments, the switching device is a transistor; The transistor includes a collector connected to the first end of a first resistor, a base connected to the collector of a phototransistor and the first end of a second resistor, and an emitter grounded.

[0009] In some embodiments, the system further includes a first reverse connection protection module connected to the controller and the common contact respectively, and a second reverse connection protection module connected to the emitter of the phototransistor, the output terminal of the switching device and the first reverse connection protection module respectively. The first anti-reverse connection module controls unidirectional conduction between the controller and the common contact point; The second reverse connection protection module controls the unidirectional conduction between the phototransistor and the switching device and the first reverse connection protection module.

[0010] In some embodiments, the first reverse connection protection module includes a bridge rectifier, and the second reverse connection protection module includes a diode; The bridge rectifier includes a first AC terminal connected to the controller, a second AC terminal grounded, a first DC terminal connected to a common contact, and a second DC terminal connected to the negative terminal of a diode. The positive terminal of the diode is connected to the emitter of a phototransistor and the emitter of a transistor, respectively.

[0011] In some embodiments, a surge protection module is further included, which is connected to the controller and the first AC terminal respectively, to suppress pulse voltage between the controller and the first reverse connection protection module.

[0012] In some embodiments, the surge protection module includes a transient voltage suppression diode; The transient voltage suppressor diode includes a first terminal connected to the controller and a first AC terminal, and a second terminal grounded.

[0013] In some embodiments, the follow-up module includes a partition and a connecting device; The partition is located between the light-emitting diode and the phototransistor, and the connecting device is connected to the partition and the moving contact respectively.

[0014] Secondly, a contactor is also proposed, including an on / off state detection circuit as described above.

[0015] The above technical solution, by setting a follower module to follow the movement of the contactor's moving contact, allows the detection module to detect the contactor's on / off state based on the position of the follower module. Whenever the contactor actuates, the detection module can detect the position change of the follower module, thus achieving direct detection of the contactor's on / off state based on the movement of the moving contact, preventing misjudgments and improving the reliability of contactor on / off state detection. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the on / off state detection circuit according to an exemplary embodiment of this application; Figure 2 This is a circuit schematic diagram of an on / off state detection circuit according to an exemplary embodiment of this application; Figure 3 This is a schematic diagram showing the positions of the partition and optocoupler in an exemplary embodiment of this application; Figure 4 This is a schematic diagram of the working principle of an on / off state detection circuit according to an exemplary embodiment of this application; Figure 5 This is another schematic diagram of the on / off state detection circuit according to an exemplary embodiment of this application.

[0018] Explanation of icon numbers: U1, optocoupler; U1A, light-emitting diode; U1B, phototransistor; R1, the first resistor; R2, the second resistor; Q1, the transistor; BR1, bridge rectifier; D1, diode; D2, transient voltage suppressor diode; 10. Partition; 20. Connecting device; 30. Circuit board.

[0019] The realization of the objectives, functional features and advantages of the embodiments of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0021] In the description of this application, the use of suffixes such as "module," "component," or "unit" to denote elements is merely for the purpose of illustrative purposes and has no specific meaning in itself. Therefore, "module," "component," or "unit" can be used interchangeably. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. Furthermore, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0022] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0023] In this application, the term "exemplary" is used to mean "used as an example, illustration, or description." Any embodiment described as "exemplary" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use this application. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that this application can be made without using these specific details. In other instances, well-known structures and processes are not described in detail to avoid obscuring the description of this application with unnecessary detail. Therefore, this application is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0024] Based on the problems in the background technology, this application proposes an on / off state detection circuit and contactor.

[0025] Firstly, referring to Figure 1 In this embodiment of the application, the on / off state detection circuit may include a follower module connected to the moving contact of the contactor, and a detection module corresponding to the follower module; wherein, during the process of the moving contact driving the follower module to move, the detection module detects the on / off state of the contactor according to the position of the follower module.

[0026] In this embodiment, the contactor may include contactors with NC contacts and contactors without NC contacts. The on / off state of the contactor may include a conducting state and a closed state. The moving contact of the contactor can drive the follower module to move with the moving contact. During the process of the contactor switching from the closed state to the conducting state, the moving contact of the contactor moves towards the stationary contact until it contacts the stationary contact, driving the follower module to move to the first position; conversely, during the process of the contactor switching from the conducting state to the contacting state, the moving contact moves away from the stationary contact until it separates from the stationary contact to the maximum distance, driving the follower module to move to the second position. In this way, the detection module can detect the on / off state of the contactor by detecting the position of the follower module.

[0027] The follow-up module can be fixedly connected to the moving contact or detachably connected. The detection module may include an inductive position sensor or an ultrasonic position detection circuit, etc.

[0028] Therefore, in this embodiment, the follower module moves along with the moving contact of the contactor, allowing the detection module to detect the on / off state of the contactor based on the position of the follower module. Whenever the contactor moves, the detection module can detect the position change of the follower module, thus directly detecting the on / off state of the contactor based on the movement of the moving contact, preventing misjudgments and improving the reliability of contactor on / off state detection. Furthermore, the on / off state detection circuit of this embodiment can be applied to contactors with NC contacts as well as those without NC contacts, demonstrating high applicability.

[0029] The following section will describe the possible specific implementation methods of the follow-up module and the detection module.

[0030] In some embodiments, refer to Figure 2 The detection module may include an optocoupler U1 and a status detection unit. The follower module is located between the light-emitting diode and the phototransistor of the optocoupler U1. The light-emitting diode includes a positive terminal connected to the power supply and a negative terminal grounded. The phototransistor includes a collector and an emitter connected to the status detection unit. When the follower module moves to different positions with the follower contact, it causes the optocoupler U1 to switch between on and off and outputs the corresponding position signal. The status detection unit determines the on / off state based on the position signal output by the follower module.

[0031] In this embodiment, when the moving contact and stationary contact of the contactor separate to their maximum distance, the follower module is positioned between the LED and phototransistor of the optocoupler U1, blocking the optical path between them. This disconnects the collector and emitter of the phototransistor, turning off the optocoupler U1 and outputting a first position signal. When the moving contact and stationary contact are in contact, the follower module is driven by the moving contact to move away from the LED and phototransistor of the optocoupler U1. This connects the optical path between the LED and phototransistor, connecting the collector and emitter of the phototransistor, turning on the optocoupler U1 and outputting a second position signal. Thus, the state detection unit can determine the on / off state of the contactor based on the received position signals. The power supply is a DC power supply used to power the optocoupler U1.

[0032] In some embodiments, refer to Figure 3 The follow-up module may include a partition 10 and a connecting device 20.

[0033] The partition 10 is located between the light-emitting diode U1A and the phototransistor U1B, and the connecting device 20 is connected to the partition 10 and the moving contact respectively.

[0034] In this embodiment, the partition 10 may include a rectangular partition, a square partition, or an irregularly shaped partition, etc. The two larger surfaces of the partition 10 are respectively positioned facing the light-emitting diode U1A and the phototransistor U1B. For example, Figure 3 As shown, the optocoupler U1 is located on one side of a circuit board 30, the partition 10 is disposed perpendicular to one side of the circuit board 30 and is located between the light-emitting diode U1A and the phototransistor U1B, and the connecting device 20 is located above the partition 10 and is detachably connected to the moving contact.

[0035] In some embodiments, refer to Figure 2 The status detection unit may include a switching device, a first resistor R1, a second resistor R2, and a controller.

[0036] The switching device may include an input terminal connected to the first end of the first resistor R1, a control terminal connected to the collector of the phototransistor and the first end of the second resistor R2 respectively, and a grounded output terminal. The second ends of the first resistor R1 and the second ends of the second resistor R2 are connected to the controller after being connected to a common contact point, and the emitter of the phototransistor is grounded.

[0037] In this embodiment, the controller can be a PLC, a microcontroller, or other similar controller.

[0038] The following explanation uses a PLC as the controller. The PLC can output a high-level detection signal PLC_V to the first resistor R1 and the second resistor R2. When the contactor is in the off state, the phototransistor is off, and the high-level detection signal PLC_V controls the switching device to conduct through the second resistor R2. Figure 4 As shown, a first current loop is formed through the first resistor R1, the second resistor R2, and the switching device. When the contactor is in the ON state, the phototransistor conducts, pulling the control terminal voltage of the switching device low to ground, thus controlling the switching device to turn off. Figure 5 As shown, a second current loop is formed through a first resistor R1 and a phototransistor. In the first current loop, the first resistor R1 and the second resistor R2 are connected in parallel, making the resistance of the first current loop less than that of the second current loop. Consequently, the current in the first current loop is greater than that in the second current loop, allowing the controller to determine the on / off state of the contactor by detecting the current magnitude.

[0039] The switching devices can be transistors, MOSFETs, and IGBTs, among others. Figure 5 For example, the switching device can be a transistor Q1. Transistor Q1 includes a collector connected to the first terminal of the first resistor R1, a base connected to the collector of a phototransistor and the first terminal of the second resistor R2, and an emitter grounded. Thus, the switching device is implemented using transistor Q1, which is less expensive than using other switching devices.

[0040] In some embodiments, the on / off state detection circuit may further include a first reverse connection protection module connected to the controller and the common contact, and a second reverse connection protection module connected to the emitter of the phototransistor, the output terminal of the switching device, and the first reverse connection protection module. The first reverse connection protection module controls unidirectional conduction between the controller and the common contact. The second reverse connection protection module controls unidirectional conduction between the phototransistor and the switching device and the first reverse connection protection module.

[0041] In this embodiment, the first reverse connection protection module and the second reverse connection protection module can be used to prevent the collector and emitter of transistor Q1 from being reverse connected, and to prevent the collector and emitter of phototransistor from being reverse connected, which would cause the on / off state detection circuit to fail, thereby improving the safety of the on / off state detection circuit.

[0042] In some embodiments, refer to Figure 2 The first reverse connection protection module may include a bridge rectifier BR1, and the second reverse connection protection module may include a diode D1.

[0043] The bridge rectifier BR1 may include a first AC terminal connected to the controller, a second AC terminal grounded, a first DC terminal connected to a common contact, and a second DC terminal connected to the negative terminal of diode D1. The positive terminal of diode D1 is connected to the emitter of phototransistor and the emitter of transistor Q1, respectively.

[0044] In this embodiment, the bridge rectifier BR1 may include a first bridge arm and a second bridge arm connected in parallel. The first bridge arm may include two diodes connected in series, and the second bridge arm may also include two diodes connected in series. The midpoint of the first bridge arm is the first AC terminal, and the midpoint of the second bridge arm is the second AC terminal. One end of the first bridge arm and the second bridge arm connected in parallel is the first DC terminal, and the other end of the first bridge arm and the second bridge arm connected in parallel is the second DC terminal.

[0045] In some embodiments, the on / off state detection circuit may further include a surge protection module connected to the controller and the first AC terminal respectively, to suppress pulse voltage between the controller and the first reverse connection protection module.

[0046] In this embodiment, the surge protection module can suppress the pulse voltage caused by the state switching of the optocoupler U1, prevent the pulse voltage from damaging the controller, and improve the reliability of the on / off state detection circuit.

[0047] In some embodiments, refer to Figure 2 The surge protection module may include a transient voltage suppressor diode D2. The transient voltage suppressor diode D2 may include a first terminal connected to the controller and a first AC terminal, and a second terminal grounded. In this embodiment, the surge protection module is implemented using the transient voltage suppressor diode D2, which is a simple implementation method.

[0048] Secondly, this application also proposes a contactor that includes a continuity state detection circuit as described in any of the above embodiments. The specific structure of the continuity state detection circuit is as described in the above embodiments. Since this contactor adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0049] The above description is merely an optional embodiment of this application and does not limit the patent scope of this application. Any equivalent structural transformations made based on the inventive concept of this application and the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A continuity / disconnection state detection circuit, characterized in that, It includes a follower module connected to the moving contact of the contactor, and a detection module corresponding to the follower module; wherein, during the process of the moving contact driving the follower module to move, the detection module detects the on / off state of the contactor according to the position of the follower module.

2. The on / off state detection circuit according to claim 1, characterized in that, The detection module includes an optocoupler and a state detection unit. The follow-up module is located between the light-emitting diode and the phototransistor of the optocoupler. The light-emitting diode includes a positive terminal connected to the power supply and a negative terminal grounded. The phototransistor includes a collector and an emitter connected to the state detection unit. When the follow-up module moves to different positions with the moving contact, it causes the optocoupler to switch between being turned on or off and outputs a corresponding position signal. The status detection unit determines the on / off state based on the position signal output by the follow-up module.

3. The on / off state detection circuit according to claim 2, characterized in that, The status detection unit includes a switching device, a first resistor, a second resistor, and a controller; The switching device includes an input terminal connected to the first end of the first resistor, a control terminal connected to the collector of the phototransistor and the first end of the second resistor respectively, and a grounded output terminal. The second ends of the first resistor and the second ends of the second resistor are connected to the controller after being connected to a common contact point. The emitter of the phototransistor is grounded.

4. The circuit according to claim 3, characterized in that, The switching device is a transistor; The transistor includes a collector connected to the first end of the first resistor, a base connected to the collector of the phototransistor and the first end of the second resistor, and a grounded emitter.

5. The on / off state detection circuit according to claim 4, characterized in that, It also includes a first reverse connection protection module that is connected to the controller and the common contact point respectively, and a second reverse connection protection module that is connected to the emitter of the phototransistor, the output terminal of the switching device and the first reverse connection protection module respectively; The first reverse connection protection module controls unidirectional conduction between the controller and the common connection point; The second reverse connection protection module controls the unidirectional conduction between the phototransistor and the switching device and the first reverse connection protection module.

6. The on / off state detection circuit according to claim 5, characterized in that, The first reverse connection protection module includes a bridge rectifier, and the second reverse connection protection module includes a diode; The bridge rectifier includes a first AC terminal connected to the controller, a second AC terminal grounded, a first DC terminal connected to the common junction, and a second DC terminal connected to the negative terminal of the diode. The positive terminal of the diode is connected to the emitter of the phototransistor and the emitter of the phototransistor, respectively.

7. The on / off state detection circuit according to claim 6, characterized in that, It also includes surge protection modules connected to the controller and the first AC terminal respectively, to suppress pulse voltage between the controller and the first reverse connection protection module.

8. The on / off state detection circuit according to claim 7, characterized in that, The surge protection module includes a transient voltage suppression diode; The transient voltage suppression diode includes a first terminal connected to the controller and the first AC terminal, and a second terminal grounded.

9. The on / off state detection circuit according to claim 2, characterized in that, The follow-up module includes a partition and a connecting device; The partition is located between the light-emitting diode and the phototransistor, and the connecting device is connected to the partition and the moving contact respectively.

10. A contactor, characterized in that, Includes the on / off state detection circuit as described in any one of claims 1 to 9.

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