Relay detection equipment and power converter
By introducing a filtering circuit and a level conversion processing circuit into the relay detection device, the problem of inaccurate detection caused by the bounce of the relay's main and auxiliary contacts is solved, and accurate status judgment is achieved in high real-time applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-06
- Publication Date
- 2026-03-10
AI Technical Summary
The main and auxiliary contacts of a relay may bounce when they are engaged, which can lead to inaccurate detection of the engagement state. This is especially true in applications with high real-time requirements, where delayed detection cannot meet the requirements.
The processing circuit filters and converts the signal of the auxiliary contact. The filtering circuit removes the bouncing interference of the auxiliary contact. The controller only identifies the closing state of the auxiliary contact after the closing time exceeds the filtering delay, thereby determining the closing state of the main contact.
It enables accurate determination of relay status without delay, meeting the requirements of high real-time applications and improving the accuracy and reliability of relay detection.
Smart Images
Figure CN223986185U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of electrical equipment detection, in particular to a detection device of a relay and a power converter. BACKGROUND
[0002] Relays are widely used in power electronic devices, especially in strong electric scenes. Relays can achieve reliable attraction and disconnection, thereby realizing the on-off of power electronic devices and subsequent circuits. For example, when a power converter is connected to the grid, the power converter can realize grid connection or off-grid through a relay.
[0003] A relay generally includes a coil and main contacts. In order to detect the state of the relay, it is necessary to detect whether the main contacts are reliably attracted. However, when the main contacts of the relay are attracted, the moving contact will bounce, and the auxiliary contact of the relay will also bounce, resulting in inaccurate attraction state detection. In view of this, the present application provides a detection device of a relay and a power converter, which can improve the accuracy of relay detection.
[0004] In view of this, the present application provides a detection device of a relay and a power converter, which can improve the accuracy of relay detection.
[0005] The present application provides a detection device of a relay, comprising: a processing circuit and a controller; an input end of the processing circuit is used to connect a first end of an auxiliary contact of a relay, a second end of the auxiliary contact is connected to a first voltage source; an output end of the processing circuit is connected to an input pin of the controller; the processing circuit is used to convert a signal of the first end of the auxiliary contact into a level signal after filtering and send the level signal to the input pin of the controller; the controller is used to judge whether the auxiliary contact of the relay is closed through a level state of the input pin.
[0006] In one possible implementation, the processing circuit comprises a detection circuit, the detection circuit comprises a switching tube; the input end of the processing circuit is a control end of the switching tube, a first end of the processing circuit is a first end of the switching tube, and a second end of the switching tube is grounded; the output end of the processing circuit is the first end or the second end of the switching tube.
[0007] In one possible implementation, the processing circuit further comprises: a filtering circuit; a first end of the filtering circuit is used to connect a first end of an auxiliary contact of a relay, a second end of the auxiliary contact is connected to a first voltage source; a second end of the filtering circuit is connected to an input end of the detection circuit, a first end of the detection circuit is connected to a second voltage, and an output end of the detection circuit is connected to an input pin of the controller; the controller is used to judge whether the auxiliary contact of the relay is closed through a level state of the input pin.
[0008] In one possible implementation, the processing circuit further includes: a first resistor and a second resistor; a first end of the first resistor is connected to a first end of the auxiliary contact, a second end of the first resistor is connected to the control terminal of the switching transistor, a first end of the second resistor is connected to the control terminal of the switching transistor, and a second end of the second resistor is grounded.
[0009] One possible implementation also includes a third resistor; the second terminal of the switching transistor is grounded through the third resistor, and the input pin of the controller is connected to the second terminal of the switching transistor.
[0010] One possible implementation further includes: a fourth resistor; the first terminal of the switching transistor is connected to the second voltage through the fourth resistor, and the input pin of the controller is connected to the first terminal of the switching transistor.
[0011] One possible implementation is that the switching transistor is a bipolar transistor or a metal-oxide-semiconductor field-effect transistor.
[0012] In one possible implementation, the processing circuit includes a comparator and a filter circuit; the first input terminal of the comparator is connected to the first terminal of the auxiliary contact through the filter circuit, the second input terminal of the comparator is connected to the second voltage, and the output terminal of the comparator is connected to the input pin of the controller.
[0013] In one possible implementation, the filter circuit includes a capacitor; the processing circuit further includes a first resistor and a second resistor; a first end of the first resistor is connected to a first end of the auxiliary contact, a second end of the first resistor is connected to a first input terminal of the comparator, a first end of the second resistor is connected to the first input terminal of the comparator, and a second end of the second resistor is grounded; the capacitor is connected in parallel with the second resistor.
[0014] In one possible implementation, the processing circuit includes a first resistor, a second resistor, and a capacitor; a first end of the first resistor is connected to a first end of the auxiliary contact, a second end of the first resistor is connected to an input pin of the controller, a first end of the second resistor is connected to an input pin of the controller, and a second end of the second resistor is grounded; the capacitor is connected in parallel with the second resistor.
[0015] This application also provides a power converter, including: a power conversion circuit, a relay, and a detection device for the relay described above; the relay includes a main contact and an auxiliary contact; the output terminal of the power conversion circuit is connected to a first terminal of the main contact, and the second terminal of the main contact is used to connect to the power grid; or, the output terminal of the power conversion circuit is connected to the first terminal of the main contact, and the second terminal of the main contact is connected to the main contact of another relay; or, the first terminal and the second terminal of the main contact are respectively connected to the power conversion circuit and the control circuit in the power converter; the detection circuit of the relay is used to detect the closed state of the auxiliary contact to obtain the closed state of the main contact.
[0016] The relay detection device provided in this application uses a filtering circuit to filter the interference caused by the bounce of the auxiliary contacts, so that the controller will not determine whether the auxiliary contacts are closed due to the high and low level changes caused by the bounce of the auxiliary contacts. Only when the closing time of the auxiliary contacts is greater than the filtering delay generated by the processing circuit will the controller recognize that the auxiliary contacts of the relay are closed, and then determine that the main contacts of the relay are closed. Attached Figure Description
[0017] Figure 1 A schematic diagram of a relay with auxiliary contacts provided for an embodiment of this application;
[0018] Figure 2A A schematic diagram of a relay detection device provided in an embodiment of this application;
[0019] Figure 2B A schematic diagram of another relay detection device provided in an embodiment of this application;
[0020] Figure 3 A schematic diagram of another relay detection device provided in an embodiment of this application;
[0021] Figure 4 A schematic diagram of another relay detection device provided in an embodiment of this application;
[0022] Figure 5 A schematic diagram of another relay detection device provided in an embodiment of this application;
[0023] Figure 6 A schematic diagram of another relay detection device provided in an embodiment of this application;
[0024] Figure 7 A schematic diagram of another relay detection device provided in an embodiment of this application;
[0025] Figure 8A A schematic diagram of another relay detection device provided in an embodiment of this application;
[0026] Figure 8B A schematic diagram of another relay detection device provided in an embodiment of this application;
[0027] Figure 9 A schematic diagram of a power converter provided in an embodiment of this application;
[0028] Figure 10 A schematic diagram of yet another power converter provided in the embodiments of this application;
[0029] Figure 11 This is a schematic diagram of another power converter provided in an embodiment of this application. Detailed Implementation
[0030] To enable those skilled in the art to better understand and implement the technical solutions provided in the embodiments of this application, the basic architecture and principle of the relay will be introduced below.
[0031] See Figure 1 The figure is a schematic diagram of a relay with auxiliary contacts provided in an embodiment of this application.
[0032] The relay provided in this application includes a main contact K1, an auxiliary contact K2, and a coil S. Taking a normally open relay as an example, when the coil S is energized, the main contact K1 closes under the influence of the magnetic field, and the auxiliary contact K2 also closes.
[0033] Pins 5 and 6 are the two ends of coil S, and pins 1 and 2 are the two ends of main contact K1. Pins 3 and 4 are the two ends of auxiliary contact K2, and main contact K1 and auxiliary contact K2 open and close simultaneously. The relay design requires that the spacing between auxiliary contact K2 and main contact K1 meet insulation safety regulations.
[0034] In practical applications, the main contacts K1 are connected to high-voltage electricity, such as for grid connection of inverters. The auxiliary contacts K2 are connected to low-voltage electricity to detect the opening and closing of the relay.
[0035] However, when a relay actually engages, both its main and auxiliary contacts may exhibit a bouncing phenomenon, meaning they rapidly alternate between closing and opening, leading to inaccurate detection of the relay's engagement state. One possible solution is delayed detection, where the relay is activated but the detection is delayed for a certain period after activation, allowing the relay's state to stabilize. However, some applications require high real-time detection of relay state transitions. For example, during the grid-connected / off-grid switching process of an inverter, seamless switching is required, such as completing the grid-connected / off-grid switching within 10ms. Delayed detection cannot meet these real-time requirements, necessitating immediate detection of the relay's state.
[0036] To achieve real-time and accurate detection of relay status, embodiments of this application provide a relay detection device that can accurately detect relay status without delay during relay status switching.
[0037] See Figure 2A The figure is a schematic diagram of a relay detection device provided in an embodiment of this application.
[0038] The relay detection device provided in this application includes: a processing circuit 1000 and a controller 30;
[0039] The input terminal of the processing circuit 1000 is used to connect to the first terminal of the auxiliary contact of the relay, and the second terminal of the auxiliary contact is connected to the first voltage source; the output terminal of the processing circuit 1000 is connected to the input pin of the controller 30.
[0040] The processing circuit 1000 is used to filter the signal at the first end of the auxiliary contact and convert it into a level signal to be sent to the input pin of the controller 30.
[0041] The controller 30 is used to determine whether the auxiliary contacts of the relay are closed by the level state of the input pin.
[0042] The processing circuit transmits the signal indicating whether the auxiliary contacts are closed to the controller. Besides filtering, the processing circuit also performs level conversion, converting the signal into a range detectable by the controller. The processing circuit may include a comparator, a switching transistor, or only a voltage divider and a filter circuit; this application does not impose specific limitations. For example, when the processing circuit includes a comparator, it also includes a filter circuit; the comparator performs level conversion, and the filter circuit performs filtering. When the processing circuit includes a switching transistor, due to the parasitic capacitance of the switching transistor, it can function as both a filter and a level converter.
[0043] The relay detection device provided in this application uses a processing circuit to filter the interference caused by the bounce of the auxiliary contact, so that the controller 30 will not determine whether the auxiliary contact K2 is closed due to the high and low level changes caused by the bounce of the auxiliary contact K2. Only when the closing time of the auxiliary contact K2 is greater than the delay generated by the processing circuit, and the processing circuit can operate normally, will the controller recognize that the auxiliary contact of the relay is closed, and then determine that the main contact of the relay is closed.
[0044] The following description, with reference to the accompanying diagram, illustrates the processing circuit of the relay detection device, including the implementation method of the switching transistor. The switching transistor combines the filtering function and the level conversion function into one, which can save hardware structure, reduce cost, and reduce the circuit area.
[0045] See Figure 2BThe figure is a schematic diagram of another relay detection device provided in an embodiment of this application.
[0046] The processing circuit provided in this application embodiment includes a detection circuit, which includes a switching transistor. In this embodiment, the switching transistor Q1 is an NPN transistor.
[0047] The input terminal of the processing circuit is the control terminal of the switching transistor Q1, the first terminal of the processing circuit is the first terminal of the switching transistor Q1, and the second terminal of the switching transistor Q1 is grounded; the output terminal of the processing circuit is either the first terminal or the second terminal of the switching transistor Q1.
[0048] The first terminal of the switching transistor Q1 is connected to a second voltage. In this embodiment, the value of the second voltage is not specifically limited, but it needs to meet the range of the controller. For example, the second voltage can be 3.3V.
[0049] The processing circuit also includes: a first resistor R1 and a second resistor R2; the first end of the first resistor R1 is connected to the first end of the auxiliary contact K2, the second end of the first resistor R1 is connected to the control terminal of the switching transistor Q1, the first end of the second resistor R2 is connected to the control terminal of the switching transistor Q1, and the second end of the second resistor R2 is grounded to GND. The first resistor R1 and the second resistor R2 form a voltage divider circuit. When the 12V voltage is high, considering that the sampling level of the controller's input pin is usually 3.3V, and the input pin can be a normal input / output (I / O) pin of the controller, a voltage divider circuit is needed using R2 and R1 to ensure that the voltage entering the controller's input pin does not exceed the allowable range of the input pin. In addition to voltage division, the first resistor R1 also has a current-limiting function. This is mainly because when the relay's auxiliary contact is engaged, a small current is required; otherwise, the engaged state cannot be maintained, affecting the detection result. This application does not specifically limit the type of controller; for example, it can be a microprocessor, a single-chip microcomputer, or a digital processor.
[0050] The relay detection device provided in this application embodiment also includes a third resistor R3;
[0051] The second terminal of the switching transistor Q1 is grounded to GND through the third resistor R3, and the input pin I / O of the controller 30 is connected to the second terminal of the switching transistor Q1.
[0052] Because the parasitic capacitance Cce between the collector and emitter of the switching transistor Q1 acts as a filter, Cce and R1 together play a filtering role, which determines the delay time. The closing signal generated by the bouncing of the auxiliary contact K2 is insufficient to be transmitted to the controller 30. Therefore, the controller 30 will not mistakenly judge that the auxiliary contact K2 is closed.
[0053] It should be understood that when the auxiliary contact K2 is not closed due to a brief bounce, after filtering, the control terminal (base) of the switch Q1 is still at a high level. At this time, the switch Q1 is turned on, and the emitter of the switch Q1 is pulled to a high level. That is, ignoring the voltage drop of the switch Q1 itself, the emitter of the switch Q1 is pulled to the second voltage of 3.3V. At this time, the input pin I / O of the controller 30 detects a high level, confirming that the auxiliary contact K2 is closed.
[0054] The following describes the implementation of relay testing equipment, including filtering circuits, testing circuits, and controllers.
[0055] See Figure 3 The figure is a schematic diagram of another relay detection device provided in an embodiment of this application.
[0056] The relay detection device provided in this application includes: a filter circuit 10, a detection circuit 20, and a controller 30.
[0057] The first terminal of the filter circuit 10 is connected to the first terminal of the auxiliary contact K2 of the relay, and the second terminal of the auxiliary contact K2 is connected to the first voltage source V1. The second terminal of the filter circuit 10 is connected to the input terminal of the detection circuit 20, the first terminal of the detection circuit 20 is connected to a second voltage (not shown in the figure), and the output terminal of the detection circuit 20 is connected to the input pin of the controller 30. This embodiment does not specifically limit the value of the first voltage source V1; for example, it can be 12V or 5V.
[0058] The embodiments of this application do not specifically limit the specific implementation of the filter circuit, and may include capacitors.
[0059] The function of the detection circuit is to transmit the signal indicating whether the auxiliary contact is closed to the controller. The detection circuit's role is level conversion, i.e., converting the signal to a range that the controller can detect. The detection circuit can be implemented using a comparator or a switching transistor; this application does not specifically limit its implementation.
[0060] The controller 30 is used to determine whether the auxiliary contact K2 of the relay is closed by the level state of the input pin.
[0061] The relay detection device provided in this application uses a filter circuit 10 to filter the interference caused by the bounce of the auxiliary contact K2, so that the controller 30 will not determine whether the auxiliary contact K2 is closed due to the high and low level changes caused by the bounce of the auxiliary contact K2. Only when the closing time of the auxiliary contact K2 is greater than the delay caused by the operation of the filter circuit 10 and the switching transistor, and the detection circuit 20 can operate normally, will the controller recognize that the auxiliary contact of the relay is closed, and then determine that the main contact of the relay is closed.
[0062] The following description uses a detection circuit that includes a switching transistor as an example. It should be understood that the switching transistor itself has parasitic capacitance, which can also play a filtering role. Therefore, when the detection circuit is a switching transistor, the filtering circuit can consist of only a resistor. Of course, the filtering circuit can also include both a resistor and a capacitor.
[0063] The embodiments of this application do not specifically limit the type of switching transistor. It can be a transistor or a MOSFET, etc. The following describes the implementation method of using a transistor as the switching transistor with reference to the accompanying drawings.
[0064] To better filter out interference signals generated by auxiliary contact bounce, see Figure 4 The figure is a schematic diagram of another relay detection device provided in an embodiment of this application.
[0065] The filtering circuit provided in this application embodiment is described using a capacitor C1 as an example; capacitor C1 is connected in parallel with the second resistor R2.
[0066] In practical applications, the resistance values of the first resistor R1, the second resistor R2, the capacitance value of the capacitor C1, and the switching transistor Q1 can be selected according to actual needs to filter out the high and low jumps in the controller's I / O level caused by the bounce of the relay's auxiliary contacts when they are energized.
[0067] Figure 3 and Figure 4 The detection circuit shown determines that the auxiliary contact of the relay is engaged when the controller 30 detects a high level. It should be understood that the controller can also determine that the auxiliary contact of the relay is engaged when it detects a low level; this will be explained in detail below with reference to the accompanying drawings.
[0068] See Figure 5 The figure is a schematic diagram of another relay detection device provided in an embodiment of this application.
[0069] The detection circuit provided in this application embodiment further includes: a fourth resistor R4.
[0070] The first terminal of the switching transistor Q1 is connected to the second voltage of 3.3V through the fourth resistor R4, and the input pin I / O of the controller 30 is connected to the first terminal of the switching transistor Q1.
[0071] In this embodiment, the filter circuit includes a first resistor R1, a second resistor R2, and a capacitor C1. It should be understood that the capacitor C1 may also be omitted, and the filtering can be achieved by utilizing the parasitic capacitance of the switching transistor Q1.
[0072] When the auxiliary contact K2 is closed, after passing through the filter circuit, the base of the switching transistor Q1 is at a high level, the switching transistor Q1 is turned on, and the input pin I / O of the controller 30 is pulled low to a low level. That is, when a low level is detected, the auxiliary contact K2 is identified as closed.
[0073] It should be understood that the switching transistor can also be other types of switching transistors, which will be described in detail below with reference to the attached diagram.
[0074] See Figure 6 The figure is a schematic diagram of another relay detection device provided in an embodiment of this application.
[0075] The switching transistor is MOSFET Q2. Taking the input I / O pin of controller 30 connected to the first terminal of MOSFET Q2 as an example, the working principle is... Figure 5 Similarly, I will not go into details here.
[0076] See Figure 7 The figure is a schematic diagram of another relay detection device provided in an embodiment of this application.
[0077] The switching transistor is MOSFET Q2. Taking the input I / O pin of controller 30 connected to the second terminal of MOSFET Q2 as an example, the working principle is... Figure 4 Similarly, I will not go into details here.
[0078] The detection circuit described above uses a switching transistor as an example. The following describes the implementation of a detection circuit that includes a comparator.
[0079] See Figure 8A The figure is a schematic diagram of another relay detection device provided in an embodiment of this application.
[0080] The detection device provided in this application embodiment includes a processing circuit comprising a filter circuit and a comparator U1. It should be understood that since the comparator does not have parasitic capacitance, the processing circuit needs to include a filter circuit. For example, the filter circuit includes a capacitor C1.
[0081] In addition, the processing circuit also includes a voltage divider circuit, with a first resistor R1 and a second resistor R2. The description of the voltage divider circuit is given in the above embodiment and will not be repeated here.
[0082] The input terminal of the detection circuit is the first input terminal of comparator U1, the first terminal of the detection circuit is the second input terminal of comparator U1, and the output terminal of the detection circuit is the output terminal of comparator U1.
[0083] The second input terminal of the comparator is connected to a second voltage V2. It should be understood that the second voltage V2 serves as a reference voltage. For example, when the voltage at the first input terminal of comparator U1 is greater than the second voltage V2, comparator U1 outputs a high level; otherwise, it outputs a low level. Alternatively, the order can be reversed: when the voltage at the first input terminal of comparator U1 is greater than the second voltage V2, comparator U1 outputs a low level; otherwise, it outputs a high level. This embodiment does not specifically limit the relationship between the output level of U1 and the first and second input terminals; it can be set according to actual needs.
[0084] The first end of the first resistor R1 is connected to the first end of the auxiliary contact K2. The second end of the first resistor R1 is connected to the first input terminal of the comparator U1. The first end of the second resistor R2 is connected to the first input terminal of the comparator U1. The second end of the second resistor R2 is grounded. The capacitor C1 is connected in parallel with the second resistor R2.
[0085] The detection device provided in this application embodiment allows the controller 30 to directly detect the output signal of the comparator U1 to determine whether the auxiliary contact K2 is closed.
[0086] It should be understood that Figures 4-8A The parasitic capacitance of the switching transistor also exists, but it is not shown in the figure.
[0087] This application also provides a relay detection device that does not necessarily include a switching transistor or comparator. It directly utilizes a voltage divider circuit and a filter circuit. By designing the parameters of the resistors in the voltage divider circuit and the parameters of the capacitors in the filter circuit, the filtering and level conversion functions can be achieved, so that the signal input to the input pin of the controller conforms to the signal processing range of the controller.
[0088] See Figure 8B The figure is a schematic diagram of another relay detection device provided in an embodiment of this application.
[0089] The processing circuit provided in this application embodiment includes a first resistor R1, a second resistor R2, and a capacitor C1.
[0090] The first end of the first resistor R1 is used to connect to the first end of the auxiliary contact K2. The second end of the first resistor R1 is connected to the input pin of the controller 30. The first end of the second resistor R2 is connected to the input pin of the controller 30. The second end of the second resistor R2 is grounded. The capacitor C1 is connected in parallel with the second resistor R2.
[0091] The relay detection device provided in this application embodiment can also filter and delay the bounce of the relay's auxiliary contacts under the filtering effect of the capacitor and the current limiting effect of the first resistor in the voltage divider circuit, thus ensuring the accuracy of the controller's detection of the auxiliary contact status.
[0092] Based on the relay detection device provided in the above embodiments, this application also provides a power converter, which will be described in detail below with reference to the accompanying drawings.
[0093] See Figure 9 This figure is a schematic diagram of a power converter provided in an embodiment of this application.
[0094] The power converter provided in this application includes: a power conversion circuit 200, a relay 100, and a relay detection device 300 as described in the above embodiments; the relay 100 includes a main contact K1, an auxiliary contact K2, and a coil S.
[0095] This application does not specifically limit the number of relays in the power converter; there can be one or more. It also does not specifically limit the specific location of the relays. For example, the output terminal of the power conversion circuit 200 is connected to the first terminal of the main contact K1, and the second terminal of the main contact K1 is used to connect to the power grid. Alternatively, see... Figure 10 This figure is a schematic diagram of another power converter provided in an embodiment of this application.
[0096] Figure 10 In the process, the power converter includes at least two relays. The output terminal of the power conversion circuit is connected to the first terminal of the main contact K1, and the second terminal of the main contact K1 is connected to the main contact of other relays S2.
[0097] Or, see Figure 11 This figure is a schematic diagram of another power converter provided in an embodiment of this application. The first and second terminals of the main contact K1 of the relay are respectively connected to the power conversion circuit 200 and the control circuit 400 in the power converter.
[0098] The relay detection circuit 300 is used to detect the closed state of the auxiliary contact K2 to obtain the closed state of the main contact K1.
[0099] The embodiments of this application do not specifically limit the topology of the power converter; for example, the power converter can be an inverter.
[0100] Since the power converter provided in this application includes the detection circuit described above, the energizing state of the relay can be accurately detected when the power conversion circuit switches between grid connection and off-grid operation via the relay, thus avoiding misjudgment.
[0101] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.
[0102] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A detecting device of a relay characterized by comprising: The application relates to a processing circuit and a controller. An input end of the processing circuit is connected with a first end of an auxiliary contact of a relay, and a second end of the auxiliary contact is connected with a first voltage source. An output end of the processing circuit is connected with an input pin of the controller. The processing circuit is used for filtering a signal of the first end of the auxiliary contact and converting the signal into a level signal to send to the input pin of the controller. The controller is used for judging whether the auxiliary contact of the relay is closed or not through a level state of the input pin. The processing circuit comprises a detection circuit, and the detection circuit comprises a switch tube.
2. The detection device of claim 1, wherein, An input end of the processing circuit is a control end of the switch tube, a first end of the processing circuit is a first end of the switch tube, a second end of the switch tube is grounded, an output end of the processing circuit is the first end or the second end of the switch tube, and a first end of the detection circuit is connected with a second voltage. The processing circuit further comprises a filtering circuit.
3. The detection device of claim 2, wherein, A first end of the filtering circuit is used for connecting a first end of an auxiliary contact of a relay, a second end of the auxiliary contact is connected with a first voltage source, a second end of the filtering circuit is connected with an input end of the detection circuit, and an output end of the detection circuit is connected with an input pin of the controller. The controller is used for judging whether the auxiliary contact of the relay is closed or not through a level state of the input pin. The processing circuit further comprises a first resistor and a second resistor.
4. The detection device of claim 3, wherein, A first end of the first resistor is used for connecting a first end of the auxiliary contact, a second end of the first resistor is connected with a control end of the switch tube, a first end of the second resistor is connected with the control end of the switch tube, and a second end of the second resistor is grounded. A third resistor is further included.
5. The detection device according to claim 3 or 4, characterized in that A second end of the switch tube is grounded through the third resistor, and an input pin of the controller is connected with the second end of the switch tube. A fourth resistor is further included.
6. The detection device according to any one of claims 2-4, characterized in that, A first end of the switch tube is connected with the second voltage through the fourth resistor, and an input pin of the controller is connected with the first end of the switch tube. The switch tube is a triode or a metal-oxide semiconductor field effect transistor. The processing circuit comprises a comparator and a filtering circuit.
7. The detection device according to any one of claims 2-3, characterized in that, A first input end of the comparator is connected with a first end of an auxiliary contact of a relay through the filtering circuit, a second input end of the comparator is connected with a second voltage, and an output end of the comparator is connected with an input pin of the controller.
8. The detection device of claim 1, wherein, The filtering circuit comprises a capacitor, and the processing circuit further comprises a first resistor and a second resistor. A first end of the first resistor is used for connecting a first end of the auxiliary contact, a second end of the first resistor is connected with a first input end of the comparator, a first end of the second resistor is connected with the first input end of the comparator, and a second end of the second resistor is grounded; and the capacitor is connected with the second resistor in parallel.
9. The detection device of claim 8, wherein, The processing circuit comprises a first resistor, a second resistor and a capacitor. 10. The detection device of claim 1, wherein, The first end of the first resistor is connected to the first end of the auxiliary contact, the second end of the first resistor is connected to an input pin of the controller, the first end of the second resistor is connected to an input pin of the controller, and the second end of the second resistor is grounded; the capacitor is connected in parallel with the second resistor.
11. A power converter, characterized by The application further discloses a detection device of a relay, a power conversion circuit, and a relay according to any one of claims 1-10. The relay comprises a main contact and the auxiliary contact. The output end of the power conversion circuit is connected to the first end of the main contact, and the second end of the main contact is connected to a power grid; or the output end of the power conversion circuit is connected to the first end of the main contact, and the second end of the main contact is connected to the main contact of another relay; or the first end and the second end of the main contact are respectively connected to the power conversion circuit and a control loop in the power converter. The detection circuit of the relay is used for detecting the closing state of the auxiliary contact to obtain the closing state of the main contact.