Relay contact detection device

Abstract

The utility model discloses a relay contact detection device, which comprises a relay, an internal power supply, a power-on circuit, a pull-in control circuit, a controller and a sampling circuit, the internal power supply is configured to provide working power for the relay; the power-on circuit is configured to be controlled by the controller, and after power-on, voltage is applied to the two ends of a relay contact through an internal power supply; the sampling circuit is configured to obtain the sampling voltage of the power-on loop and feed back a detection signal to the controller; the pull-in control circuit is configured to be controlled by the controller, and after voltage is applied to the two ends of a relay contact, pull-in voltage is provided for a relay coil through an internal power supply; the controller is configured to control the power-on circuit and the pull-in control circuit and receive the detection signal so as to determine the state of the relay contact. According to the scheme of the utility model, the relay contact adhesion phenomenon can be accurately and effectively detected, and the working safety of the relay is ensured.

Description

Technical Field

[0001] The utility model relates to the field of circuits, and particularly to a relay contact detection device. Background Art

[0002] A relay is an electrical control device, which is usually applied to an automatic control circuit. The working characteristics of relay contacts are that they need to be switched on and off frequently and pass through large currents. To avoid the occurrence of relay contact adhesion, usually before the relay works, the contacts need to be detected first to determine whether the contacts can be normally attracted and disconnected. Therefore, how to effectively and accurately detect the relay contact adhesion phenomenon is an important problem that the industry needs to solve. Summary of the Utility Model

[0003] The utility model provides a relay contact detection device, which can accurately and effectively detect the relay contact adhesion phenomenon and ensure the safety of relay operation.

[0004] For this reason, the utility model provides the following technical solutions:

[0005] An embodiment of the utility model provides a relay contact detection device, including: a relay, a power-on circuit and a pull-in control circuit connected to the relay, and an internal power supply, a controller, and a sampling circuit connected to the power-on circuit; the internal power supply provides a working power supply for the relay through the power-on circuit; the pull-in control circuit provides a pull-in voltage for the relay coil;

[0006] The power-on circuit and the pull-in control circuit are controlled by the controller;

[0007] The sampling circuit acquires a sampling voltage of the power-on loop and feeds back a detection signal to the controller;

[0008] The controller receives the detection signal.

[0009] Optionally, the power-on circuit includes: a switch module, a transformer, and a power feeding module;

[0010] The switch module is configured to be controlled by the controller;

[0011] The transformer is configured to store the energy of the internal power supply after connecting to the internal power supply, and transfer the stored energy to the power feeding module;

[0012] The power feeding module is configured to convert the acquired energy into a voltage applied across the contacts of the relay.

[0013] Optionally, the switch module includes: a driving unit, a switching unit, and a sampling resistor;

[0014] The driving unit is configured to receive the power-on signal sent by the controller when powering on, and amplify and output the power-on signal;

[0015] The switching unit is configured to receive the power-on signal output by the driving unit and connect the transformer and the internal power supply;

[0016] The internal power supply, the transformer, the switching unit, and the sampling resistor form the power-on loop.

[0017] Optionally, the switching unit includes: a first switching tube and a first driving resistor connected to the switching tube.

[0018] Optionally, the transformer includes a primary side and a secondary side; both ends of the primary side are respectively connected to the internal power supply and the switching unit.

[0019] Optionally, the power feeding module includes: a rectifying and filtering unit connected to the secondary side of the transformer and a dummy load resistor connected to the rectifying and filtering unit, and both ends of the dummy load resistor are also respectively connected to both ends of the contact of the relay.

[0020] Optionally, the rectifying and filtering unit includes: a rectifying diode and a filtering capacitor connected to the rectifying diode; the rectifying diode is also connected to one end of the secondary side, and the filtering capacitor is also connected to the other end of the secondary side.

[0021] Optionally, the pulling-in control circuit includes: a second switching tube, a second driving resistor connected to the second switching tube and the controller, and a pull-down resistor connected to the second switching tube.

[0022] Optionally, there are multiple relays, and the multiple relays are connected in parallel.

[0023] Optionally, each relay is controlled by an independent pulling-in control circuit.

[0024] Optionally, the power-on circuit is configured to be controlled by the controller; the controller is configured to sequentially control the pulling-in control circuits corresponding to the respective relays to provide a pulling-in or disconnecting voltage for the coil of the relay.

[0025] Optionally, the multiple relays are controlled by a common pulling-in control circuit.

[0026] Optionally, the power-on circuit is configured to be controlled by the controller; the controller is configured to control the pulling-in control circuit to simultaneously provide a pulling-in or disconnecting voltage for the coils of the multiple relays.

[0027] The relay contact detection device provided by this embodiment utilizes an internal power supply to power the relay during contact testing, eliminating the need for an external power supply. This not only facilitates testing and reduces energy consumption, but also ensures safety during the testing process. By sampling the power-on circuit voltage, the device can effectively detect contact sticking during operation and accurately detect contact sticking even before power is applied.

[0028] Furthermore, in the relay contact detection device provided by the embodiment of the present invention, the power-on circuit uses a transformer to power on the relay, which can better isolate the input and output circuits. The output of the transformer is connected to the two ends of the relay contacts. When power is on, the transformer has output when the contacts are disconnected, and has no output when the contacts are closed. That is to say, when power is on, it is not affected by whether the feeding module fails. An output short circuit can indicate that the contact is in the closed state, that is, the relay contact is stuck. During the working process after power-on, combined with the coil voltage of the relay, it can be conveniently and accurately determined whether the relay contacts are stuck.

[0029] Furthermore, the relay contact detection device provided by the present invention can also detect the contact status of multiple relays connected in parallel. Furthermore, it can not only determine whether any relay contacts are stuck, but also locate the specific relay triggering the sticking phenomenon, facilitating relay contact status detection in multi-relay application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a structural diagram of a relay contact detection device provided by an embodiment of the present utility model;

[0031] Figure 2 This is a schematic diagram of a specific structure of the relay contact detection device provided by an embodiment of the utility model;

[0032] Figure 3 This is another specific structural diagram of the relay contact detection device provided by an embodiment of the utility model;

[0033] Figure 4 This is another structural diagram of the relay contact detection device provided by an embodiment of the present utility model;

[0034] Figure 5 This is another structural diagram of the relay contact detection device provided by an embodiment of the present utility model. DETAILED DESCRIPTION

[0035] In order to make the above-mentioned objects, features and beneficial effects of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0036] Existing relay contact detection circuits usually cut off the power supply to the relay coil after the relay contacts are closed, and cooperate with the discharge circuit and the output-side capacitor to collect the output voltage to determine whether the relay contacts are stuck. This method has the following disadvantages: 1) If the discharge circuit fails, it is also impossible to determine whether the relay contacts are stuck; 2) The discharge of the discharge circuit to the output voltage takes a certain amount of time, and the discharge time is related to the capacitance of the output-side capacitor. It is necessary to test to determine the corresponding threshold, and a judgment result can be given only when the detected output voltage drops to this threshold. In the presence of line interference, misjudgment is likely to occur.

[0037] In view of the above problems existing in the existing relay contact detection circuit, an embodiment of the present invention provides a relay contact detection device. When detecting the relay contacts, the relay is powered by an internal power supply, and the sampling voltage of the power-on circuit is collected to detect whether the relay contacts are stuck.

[0038] As Figure 1 shown, it is a schematic structural diagram of a relay contact detection device provided by an embodiment of the present invention.

[0039] The relay contact detection device of this embodiment includes: a relay K1, an internal power supply V2, a power-on circuit L1, a pull-in control circuit L2, a controller U1, and a sampling circuit U3. The relay K1 includes a coil and contacts, and a freewheeling diode D1 connected in parallel with the coil. Among them: the coil of the relay K1 is connected to the pull-in control circuit L2, the contacts of the relay K1 are connected to the power-on circuit L1, the controller U1 is respectively connected to the power-on circuit L1, the pull-in control circuit L2, and the sampling circuit U3, and the sampling circuit U3 is also connected to the power-on circuit L1.

[0040] The internal power supply V2 provides a working power supply for the relay K1 through the power-on circuit L1;

[0041] The pull-in control circuit L2 provides a pull-in voltage for the relay coil;

[0042] Both the power-on circuit L1 and the pull-in control circuit L2 are controlled by the controller U1. Specifically, after power-on, the internal power supply V2 applies a voltage across the contacts of the relay K1 through the power-on circuit L1; after a voltage is applied across the contacts of the relay K1, the pull-in control circuit L2 provides a pull-in voltage for the coil of the relay K1 through the internal power supply

[0043] The sampling circuit U3 obtains the sampling voltage of the power-on circuit and feeds back a detection signal to the controller U1.

[0044] Correspondingly, the controller U1 receives the detection signal to determine the state of the contacts of the relay K1.

[0045] In this embodiment, when power is applied, the controller U1 sends a power-on signal (such as a square wave signal) to the power-on circuit L1, causing the internal power supply V2 and the power-on circuit L1 to form a power-on loop. The power-on circuit L1 obtains the energy of the internal power supply V2. At this time, the sampling circuit U3 obtains the sampling voltage of the power-on loop, converts it into a signal recognizable by the controller U1, that is, the detection signal, and feeds the detected signal back to the controller U1. For the convenience of description, the detection signal output at this time is called sign1. According to sign1, it can be determined whether the contacts of the relay K1 are adhered. Specifically, if the contacts of the relay K1 are not adhered, the sampling voltage at this time will not exceed the threshold set by the controller; if the contacts of the relay K1 are adhered, the sampling voltage at this time will exceed the threshold set by the controller.

[0046] If the contacts of the relay K1 are normal, the power-on circuit L1 converts the obtained energy into a voltage and applies it to both ends of the contacts of the relay K1, causing the contacts of the relay K1 to be in the power-on state.

[0047] Then, the controller U1 sends a first control signal to the pull-in control circuit L2, causing the pull-in control circuit L2 to provide the voltage required for pulling in for the coil of the relay K1. For example, the internal power supply V2 can be used to provide the pull-in power for the coil of the relay K1, and the contacts of the relay K1 are pulled in. After the contacts of the relay K1 are pulled in, the output side of the power-on circuit L1 is in a short-circuit state. At this time, the sampling circuit U3 converts the sampling voltage into a signal recognizable by the controller U1, that is, the detection signal. For the convenience of description, the detection signal output at this time is called sign2.

[0048] Then, the controller U1 sends a second control signal to the pull-in control circuit L2, causing the pull-in control circuit L2 to stop providing the voltage required for pulling in for the coil of the relay K1. If the contacts of the relay K1 are normal, the contacts should be disconnected at this time. At this time, the sampling circuit U3 converts the sampling voltage into a signal recognizable by the controller U1, that is, the detection signal output to the controller U1. For the convenience of description, the detection signal output at this time is called sign3. At this time, sign3 will not exceed the threshold set by the controller; if the contacts of the relay K1 are adhered, sign3 will exceed the threshold set by the controller.

[0049] It should be noted that the first control signal can be a high-level signal, and the second control signal is a low-level signal.

[0050] To avoid false detection, the above process can also be repeated multiple times when the pull-in control circuit L2 disconnects the power supply of the coil of the relay K1 to ensure the accuracy of the detection result.

[0051] Such as Figure 2As shown, in a non - restrictive embodiment, the above - mentioned power - on circuit may include: a switch module 11, a transformer 12, and a power - feeding module 13. Among them:

[0052] The switch module 11 is configured to be controlled by the controller U1 to connect or disconnect the transformer 12 from the internal power supply V2;

[0053] The transformer 12 is configured to store the energy of the internal power supply V2 after connecting to the internal power supply V2; after disconnecting from the internal power supply V2, transfer the stored energy to the power - feeding module 13;

[0054] The power - feeding module 13 is configured to convert the acquired energy into a voltage applied across the contacts of the relay K1.

[0055] As Figure 3 shown, it is another specific structural schematic diagram of the relay contact detection device provided by the embodiment of the present invention.

[0056] At the same time, in combination with Figure 2 and Figure 3 , a non - restrictive embodiment of the above - mentioned switch module 11 may include: a driving unit U2, a switch unit, and a sampling resistor R5. The switch unit includes a first switching transistor Q1 and a first driving resistor R4 connected thereto.

[0057] In this embodiment, the transformer T1 includes a primary side and a secondary side; the two ends of the primary side are respectively connected to the internal power supply V2 and the first switching transistor Q1 of the switch unit.

[0058] The above - mentioned power - feeding module 13 includes a rectifying and filtering unit connected to the secondary side of the transformer T1, and a dummy load resistor R6 connected to the rectifying and filtering unit. The two ends of the dummy load resistor R6 are also respectively connected to the two ends of the contacts of the relay K1. In this embodiment, the rectifying and filtering unit includes: a rectifying diode D2, and a filtering capacitor C1 connected to the rectifying diode D2. The rectifying diode D2 is also connected to one end of the secondary side, and the filtering capacitor C1 is also connected to the other end of the secondary side.

[0059] In this embodiment, the driving unit U2 is configured to receive the power - on signal sent by the controller U1 during power - on, and amplify and output the power - on signal.

[0060] Correspondingly, the switch unit is configured to receive the power - on signal output by the driving unit U2 and connect the transformer T1 and the internal power supply V2. Specifically, as Figure 3 shown, after the switching transistor Q1 receives the power - on signal, it connects the primary side of the transformer T1 and the internal power supply V2. At this time, the internal power supply V2, the primary side of the transformer T1, the switching transistor Q1, and the sampling resistor R5 form a power - on loop.

[0061] Accordingly, the sampling circuit U3 obtains the voltage on the sampling resistor R5 and outputs a detection signal to the controller U1 according to the voltage.

[0062] Continue to refer to Figure 2 and Figure 3 In this embodiment, a non-limiting embodiment of the above-mentioned pull-in control circuit L2 may include: a second switch tube Q2, a second driving resistor R7 connected to the second switch tube Q2 and the controller U1, and a pull-down resistor R8 connected to the second switch tube Q2.

[0063] The following combination Figure 2 The working process of the relay contact detection device is further described in detail.

[0064] First, controller U1 generates a square wave signal with a certain duty cycle (for example, a duty cycle of 0.5). Driver U2 drives and amplifies this square wave signal, turning on first switch Q1 at a certain frequency. Internal power supply V2, the primary side of transformer T1, switch Q1, and sampling resistor R5 form a power-on circuit. Sampling circuit U3 captures the voltage signal across sampling resistor R5 and converts it into a detection signal recognizable by controller U1. This detection signal can be used as one of the criteria for determining whether the contacts of relay K1 are stuck. For example, if relay K1's contacts are stuck, the secondary side of transformer T1 is short-circuited, and the sampled voltage across sampling resistor R5 exceeds a set threshold. Sampling circuit U3 then feeds back a detection signal to controller U1 that is greater than a set value (for example, 2V). Otherwise, the signal fed back to controller U1 is a voltage signal that is less than the set value.

[0065] When the switch tube Q2 is turned off, the secondary side of the transformer T1 works, and a stable voltage is generated through the rectifier diode, the output filter capacitor C1, and the output dummy load resistor R6. This voltage is applied to both ends of the contacts of the relay K1.

[0066] The controller U1 issues a command to activate the relay coil, for example, by outputting a high-level signal through the corresponding I / O port. After passing through the driving resistor R7, the switching transistor Q2 is turned on. After the switching transistor Q2 is turned on, the input power supply V2 supplies the voltage required for activation to the relay coil of the relay K1 through the switching transistor Q2 and the pull-down resistor R8. After the contacts are closed, the output side of the transformer is in a short-circuit state. The short-circuit current is equivalent to the current sampling resistor R5 on the primary side. The current sampling resistor R5 converts the short-circuit current into a signal that can be recognized by the DSP controller through the sampling circuit. At this time, the controller U1 issues a command to start the switching transistor Q1 once every 1 mS, and the transformer is in a continuous restart state. The controller U1 stops sending the command to activate the relay coil, the switching transistor Q2 is turned off, and the relay coil of the relay K1 loses the condition for activation. Under normal circumstances, the contacts of the relay K1 can be normally disconnected, the output side of the transformer is no longer short-circuited, the primary current of the transformer T1 flows through the sampling resistor R5, and the signal fed back by the sampling circuit U3 to the controller U1 does not exceed the set threshold. When the relay contacts are not adhered, the controller U1 issues a normal driving waveform (i.e., the power-on signal described above), and at this time the transformer should output normally. When the switching transistor Q2 is turned off, if the power-on circuit is still in a continuous restart state, it is determined that there is an adhesion phenomenon of the relay contacts. Accordingly, the controller U1 can determine whether there is an adhesion phenomenon of the contacts of the relay K1 according to the states of the coil activation control signal and the driving signal of the switching transistor Q1.

[0067] The relay contact detection device provided by the embodiment of the present invention uses an internal power supply to supply power to the relay when detecting the relay contacts, without an external power supply. This not only facilitates the detection operation, reduces energy consumption, but also ensures the safety of the detection process. By collecting the sampling voltage of the power-on circuit, it is not only possible to effectively detect the contact adhesion during the working process, but also accurately detect the situation where the contacts are adhered before power-on.

[0068] Using the relay contact detection device provided by the embodiment of the present invention, it is also possible to detect the contact states of multiple relays connected in parallel. Moreover, it can not only determine whether there is an adhesion phenomenon in the relay contacts, but also locate which specific relay trigger has an adhesion phenomenon, facilitating the detection of the contact states of relays in multi-group relay application scenarios.

[0069] As Figure 4 shown, it is another structural schematic diagram of the relay contact detection device provided by the embodiment of the present invention.

[0070] In this example, the relay contact detection device can simultaneously detect whether there is an adhesion phenomenon in the contacts of multiple relays connected in parallel.

[0071] Multiple parallel relays share the same power-on circuit, and each of the multiple parallel relays is controlled by an independent pull-in control circuit.

[0072] When powering on, the controller U1 controls the power-on circuit to apply voltage to both ends of the contacts of multiple relays simultaneously through the internal power supply V2, and can sequentially control the pull-in control circuits corresponding to each relay to provide pull-in voltage for the corresponding relay coils, so as to detect whether there is adhesion between the contacts of each relay. The specific detection process is similar to the previous one and will not be elaborated here.

[0073] Using the relay contact detection device of this embodiment, not only can it detect whether there is adhesion between the contacts of multiple relays, but also the detection result can be located to a specific relay to achieve precise detection.

[0074] As Figure 5 shown, it is another structural schematic diagram of the relay contact detection device provided by the embodiment of the present invention.

[0075] In this example, multiple relays are connected in parallel and share the same power-on circuit and the same pull-in control circuit.

[0076] When powering on, the controller U1 controls the power-on circuit to apply voltage to both ends of the contacts of multiple relays simultaneously through the internal power supply V2, and determines whether there is adhesion between the contacts of multiple parallel relays according to the detection signal fed back by the sampling circuit U3. Because as long as the contacts in any one of the relays are adhered, the output side of the transformer will be in a short-circuit state, and the short-circuit current is applied to the original additional current sampling resistor R5. The sampling circuit U3 converts the short-circuit current into a signal that the controller U1 can recognize, and the controller U1 can determine that there is adhesion between the contacts of a relay.

[0077] Otherwise, since the second switching transistor Q2 is in the off state, the secondary side of the transformer T1 works, and through the rectifier diode D2 and the filter capacitor C1, a stable voltage is generated on the output false load resistor R6, and this voltage is applied to both ends of the contacts of the relays K1 to Kn.

[0078] Then, the controller U1 issues a relay coil pull-in command, controls the second switching transistor Q2 to conduct through the driving resistor R7. After Q2 conducts, the internal power supply V2 supplies the voltage required for pull-in to the coils of the relays K1 to Kn through the second switching transistor Q2 and the pull-down resistor R8. After the contacts are pulled in, the output side of the power-on circuit is in a short-circuit state, and the short-circuit current is equivalent to the current sampling resistor R5 on the primary side. The sampling circuit U3 converts the short-circuit current into a signal that the controller U1 can recognize. At this time, the contacts are in a normal pulled-in state.

[0079] Thereafter, the controller U1 controls the second switching transistor Q2 to conduct, and repeats the above process. The controller U1 can accurately determine whether there is adhesion of the relay contacts by combining the received detection signal and the current suction instruction of the wire package.

[0080] Compared with Figure 4 the embodiment shown, Figure 5 Although the solution of the embodiment cannot accurately locate the detection result to a specific relay, the circuit is simpler, the detection efficiency is higher, and it can better adapt to some specific application scenarios and meet the high-efficiency detection requirements of multiple parallel relays.

[0081] In the embodiments of the present invention, "a plurality of" refers to two or more.

[0082] In the embodiments of the present invention, the descriptions such as first and second are only for indicating and distinguishing the described objects, without order, and do not represent a special limitation on the number of devices in the embodiments of the present invention, and cannot constitute any limitation to the embodiments of the present invention.

[0083] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined by the claims.

Claims

1. A relay contact detection device, characterized in that, Comprising: A relay, a power-on circuit and a pull-in control circuit connected to the relay, and an internal power supply, a controller, and a sampling circuit connected to the power-on circuit; The internal power supply provides a working power supply for the relay through the power-on circuit; the pull-in control circuit provides a pull-in voltage for the relay coil; The power-on circuit and the pull-in control circuit are controlled by the controller; The sampling circuit acquires a sampling voltage of the power-on loop and feeds back a detection signal to the controller; The controller receives the detection signal.

2. The relay contact detection device according to claim 1, wherein The power-on circuit includes: a switch module, a transformer, and a power supply module; The switch module is configured to be controlled by the controller; The transformer is configured to store the energy of the internal power supply after connecting to the internal power supply, and transfer the stored energy to the power supply module; The power supply module is configured to convert the acquired energy into a voltage applied across the contacts of the relay.

3. The relay contact detection device according to claim 2, characterized in that, The switch module includes: a driving unit, a switching unit, and a sampling resistor; The driving unit is configured to receive a power-on signal sent by the controller during power-on, and amplify and output the power-on signal; The switching unit is configured to receive the power-on signal output by the driving unit and connect the transformer and the internal power supply; The internal power supply, the transformer, the switching unit, and the sampling resistor form the power-on loop.

4. The relay contact detection device according to claim 3, wherein, The switching unit includes: a first switching transistor and a first driving resistor connected to the switching transistor.

5. The relay contact detection device according to claim 3, characterized in that, The transformer includes a primary side and a secondary side; both ends of the primary side are respectively connected to the internal power supply and the switching unit.

6. The relay contact detection device according to claim 5, wherein, The power supply module includes: a rectifying and filtering unit connected to the secondary side of the transformer, and a dummy load resistor connected to the rectifying and filtering unit, and both ends of the dummy load resistor are also respectively connected to both ends of the contacts of the relay.

7. The relay contact detection device according to claim 6, characterized in that, The rectifying and filtering unit includes: a rectifying diode and a filtering capacitor connected to the rectifying diode; the rectifying diode is also connected to one end of the secondary side, and the filtering capacitor is also connected to the other end of the secondary side.

8. The relay contact detection device according to claim 1, characterized in that, The pull-in control circuit includes: a second switching transistor, a second driving resistor connected to the second switching transistor and the controller, and a pull-down resistor connected to the second switching transistor.

9. The relay contact detection device according to any one of claims 1 to 8, characterized in that There are multiple relays, and the multiple relays are connected in parallel.

10. The relay contact detection device according to claim 9, characterized in that, Each relay is controlled by its own independent pull-in control circuit.

11. The relay contact detection device according to claim 10, wherein The power-on circuit is configured to be controlled by the controller; The controller is configured to sequentially control the pull-in control circuits corresponding to each relay to provide a pull-in or disconnect voltage for the relay coil.

12. The relay contact detection device according to claim 9, characterized in that, The multiple relays are controlled by a common pull-in control circuit.

13. The relay contact detection device according to claim 12, wherein The power-on circuit is configured to be controlled by the controller; The controller is configured to control the pull-in control circuit to simultaneously provide a pull-in or disconnect voltage for the coils of the multiple relays.

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