A self-test circuit, method and residual current detection device

Abstract

The present invention discloses a self-test circuit, method and residual current detection device. The self-test circuit includes: a first terminal for inputting a detection voltage; a second terminal for connecting to a reference ground; a third terminal for inputting a first control signal to enable the self-test circuit to enter a first conduction state to detect whether the detection accuracy of the residual current detection device is abnormal; a fourth terminal, on the basis of maintaining the third terminal inputting the first control signal, the fourth terminal inputs a second control signal to enable the self-test circuit to enter a second conduction state to detect whether the detection ratio of the residual current detection device is abnormal; wherein the detection ratio is the proportional relationship between the residual current detection value and the actual residual current value of the detected device. Through the present invention, before the residual current detection device is formally used, a self-test is first performed to ensure the accuracy of the detection result, so as to avoid affecting the normal operation of the converter due to the inability of the residual current detection device to accurately measure the residual current.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic circuits, and in particular to a self-test circuit, method and residual current detection device. Background Art

[0002] In photovoltaic power generation intelligent converters that meet the requirements of electrical safety design, residual current detection devices must be provided. Whether it is a residual current detection device that is on-board and requires external threading, or a residual current detection device that is on-board and comes with its own wires, it does not have a self-test circuit by itself, and an external circuit needs to be added to achieve self-test. If there is no self-test circuit in the external supporting circuit, it is not certain whether the conduction, detection accuracy, and detection ratio of the residual current detection device are normal when the intelligent converter is powered on. When the detection accuracy or detection ratio of the residual current detection device is abnormal, the detection result cannot reflect the actual residual current of the converter, causing the residual current to be too small when the intelligent converter is powered on, but repeatedly misprotected, or the residual current exceeds the standard and the converter does not report a fault. No matter which situation occurs, it will affect the normal operation of the converter, and in serious cases it may even endanger personal safety and easily cause safety accidents.

[0003] Currently, no effective solution has been proposed to solve the problem that the detection accuracy or detection ratio of the residual current detection device in the prior art is abnormal, resulting in the detection result failing to reflect the actual residual current situation of the converter. Summary of the invention

[0004] The embodiments of the present invention provide a self-test circuit, method and residual current detection device to solve the problem that the detection accuracy or detection ratio of the residual current detection device in the prior art is abnormal, resulting in the detection result failing to reflect the actual residual current situation of the converter.

[0005] In order to solve the above technical problems, the present invention provides a self-test circuit, which is applied to a residual current detection device, and includes:

[0006] A first terminal for inputting a detection voltage;

[0007] The second terminal is connected to the reference ground;

[0008] A third terminal is used to input a first control signal to enable the self-detection circuit to enter a first conduction state to detect whether the detection accuracy of the residual current detection device is abnormal;

[0009] The fourth terminal inputs the second control signal on the basis of maintaining the first control signal input to the third terminal, so that the self-test circuit enters the second conduction state to detect whether the detection ratio of the residual current detection device is abnormal; wherein the detection ratio is the proportional relationship between the residual current detection value and the actual residual current value of the detected device.

[0010] Furthermore, the self-test circuit comprises:

[0011] A first detection branch, arranged between the first terminal and the second terminal, configured to be turned on under the control of the first control signal so that the self-test circuit enters a first conduction state;

[0012] The second detection branch is connected in parallel with the first detection branch, and is used to be turned on under the control of the second control signal after the first detection branch is turned on, so that the self-test circuit enters a second conduction state.

[0013] Furthermore, the first detection branch and the second detection branch include at least one resistor.

[0014] Furthermore, at least one resistor in the first detection branch or the second detection branch is a variable resistor.

[0015] Furthermore, the self-test circuit further comprises:

[0016] A first switch is provided between a connection point between the first detection branch and the second detection branch and the second terminal, and is used to be turned on under the control of the first control signal, thereby controlling the first detection branch to be turned on;

[0017] The second switch is arranged on the second detection branch, and is used to be turned on under the control of the second control signal on the basis of the first switch being turned on, thereby controlling the second detection branch to be turned on.

[0018] Furthermore, the self-test circuit further comprises:

[0019] A third switch is provided between a connection point between the first detection branch and the second detection branch and the first terminal;

[0020] The fifth terminal is used to input a third control signal to turn on the third switch.

[0021] Furthermore, the self-test circuit further comprises:

[0022] A first wiring terminal and a second wiring terminal, wherein the first wiring terminal and the second wiring terminal are arranged between the connection point of the first detection branch and the second detection branch and the first terminal, the first wiring terminal is used to connect the first end of the detection wire of the residual current detection device, and the second wiring terminal is used to connect the second end of the detection wire.

[0023] Furthermore, the self-test circuit further comprises: a conversion module, configured to convert a first control signal inputted from the third terminal to obtain a first conversion signal, wherein the first conversion signal is configured to control the self-test circuit to enter a first conduction state;

[0024] The conversion module is further used for converting a second control signal inputted from the fourth terminal to obtain a second conversion signal, wherein the second conversion signal is used for controlling the self-test circuit to enter a second conduction state.

[0025] The present invention also provides a residual current detection device, comprising the above self-test circuit.

[0026] The present invention also provides a converter, comprising the above residual current detection device.

[0027] The present invention also provides a self-test method, which is applied to the above self-test circuit, and the method comprises:

[0028] triggering a first control signal input to cause the self-test circuit to enter a first conduction state, so as to determine whether the detection accuracy of the residual current detection device is abnormal;

[0029] If the detection accuracy of the residual current detection device is normal, the second control signal input is triggered on the basis of maintaining the first control signal input, so that the self-test circuit enters the second conduction state to determine whether the detection ratio of the residual current detection device is abnormal.

[0030] Further, judging whether the detection accuracy of the residual current detection device is abnormal includes:

[0031] Determine whether the residual current detection value is consistent with the calculated value;

[0032] If yes, it is determined that the detection accuracy of the residual current detection device is normal;

[0033] If not, it is determined that the detection accuracy of the residual current detection device is abnormal.

[0034] Further, judging whether the detection ratio of the residual current detection device is abnormal includes:

[0035] respectively calculating a first ratio between a residual current detection value in a first conduction state and a residual current detection value in a second conduction state, and a second ratio between a residual current calculation value in the first conduction state and a residual current calculation value in the second conduction state;

[0036] determining whether the first ratio is consistent with the second ratio;

[0037] If yes, it is determined that the detection ratio of the residual current detection device is normal;

[0038] If not, it is determined that the detection ratio of the residual current detection device is abnormal.

[0039] Furthermore, before determining whether the detection accuracy of the residual current detection device is abnormal, the method further includes:

[0040] Determine whether residual current is detected;

[0041] If not, it is determined that the residual current detection device is abnormally conductive;

[0042] If yes, it triggers the determination of whether the detection accuracy of the residual current detection device is abnormal.

[0043] Further, triggering a first control signal input so that the self-test circuit enters a first conduction state includes:

[0044] The first control signal input is triggered to turn on the first switch, thereby controlling the first detection branch to turn on, so that the self-test circuit enters a first conduction state.

[0045] Further, triggering the second control signal input on the basis of maintaining the first control signal input so as to make the self-test circuit enter the second conduction state includes:

[0046] The second control signal input is triggered to turn on the second switch, thereby controlling the second detection branch to turn on, so that the self-test circuit enters the second conduction state.

[0047] Furthermore, before triggering the first control signal input, the method further includes:

[0048] The third control signal input is triggered to turn on the third switch; wherein the third switch is arranged between the connection point of the first detection branch and the second detection branch and the first terminal of the self-detection circuit.

[0049] The present invention also provides a computer-readable storage medium on which a computer program is stored, and the program implements the above self-checking method when executed by a processor.

[0050] By applying the technical solution of the present invention, the self-test circuit inputs a detection voltage through the first terminal; connects to the reference ground through the second terminal to form a current loop with the first terminal; inputs a first control signal through the third terminal to make the self-test circuit enter a first conduction state to detect whether a residual current is generated and determine whether the value of the residual current is abnormal; and inputs a second control signal through the fourth terminal on the basis of maintaining the first control signal input at the third terminal to make the self-test circuit enter a second conduction state to detect whether the detection ratio of the residual current detection device is abnormal. Before the residual current detection device is officially used, a self-test can be performed first to ensure the accuracy of the detection result and avoid affecting the normal operation of the converter due to the inability of the residual current detection device to accurately measure the residual current. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 is a structural diagram of a self-test circuit according to an embodiment of the present invention;

[0052] Figure 2 is a structural diagram of a self-test circuit according to an embodiment of the present invention;

[0053] Figure 3 is a structural diagram of a self-test circuit according to another embodiment of the present invention;

[0054] Figure 4 is a flow chart of a detection method according to an embodiment of the present invention;

[0055] Figure 5 is a flow chart of a detection method according to another embodiment of the present invention;

[0056] Figure 6 FIG. 4 is a flow chart of a detection method according to another embodiment of the present invention. DETAILED DESCRIPTION

[0057] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0058] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings, and "multiple" generally includes at least two.

[0059] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0060] It should be understood that, although the terms first, second, etc. may be used to describe the detection branch in the embodiments of the present invention, these detection branches should not be limited to these terms. These terms are only used to distinguish different detection branches. For example, without departing from the scope of the embodiments of the present invention, the first detection branch may also be referred to as the second detection branch, and similarly, the second detection branch may also be referred to as the first detection branch.

[0061] As used herein, the words "if" and "if" may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0062] It should also be noted that the term "includes", "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, so that a commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprising a ..." do not exclude the existence of other identical elements in the commodity or device including the elements.

[0063] The optional embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0064] Example 1

[0065] This embodiment provides a self-test circuit, which is applied to a residual current detection device. Figure 1 is a structural diagram of a self-test circuit according to an embodiment of the present invention, such as Figure 1 As shown, the self-test circuit comprises: a first terminal 1 for inputting a test voltage, wherein the test voltage is provided by an external power supply or output by a residual current detection device; and a second terminal 2 connected to a reference ground to form a current loop.

[0066] The self-test circuit further comprises a third terminal 3 for inputting a first control signal to enable the self-test circuit to enter a first conducting state, so as to detect whether the detection accuracy of the residual current detection device is abnormal.

[0067] If the detection accuracy of the residual current detection device is normal, it is also necessary to determine whether its detection ratio is accurate. Therefore, the self-test circuit of this embodiment further includes a fourth terminal 4. On the basis of maintaining the first control signal input to the third terminal 3, the fourth terminal 4 inputs a second control signal to enable the self-test circuit to enter a second conduction state to detect whether the detection ratio of the residual current detection device is abnormal. In the first conduction state and the second conduction state, the total resistance value of the self-test circuit is different. If the detection accuracy and / or the detection ratio are abnormal, it indicates that the detection result of the residual current detection device is abnormal and cannot reflect the residual current actually generated in the detected device.

[0068] When the residual current detection device detects the current of the converter, the converter is located on the primary side, and the residual current detection device is located on the secondary side. If residual current is generated in the converter on the primary side, an induced current will be generated in the residual current detection device on the secondary side. The value of the induced current is the residual current detection value. The above detection ratio is the proportional relationship between the residual current detection value obtained by the residual current detection device and the residual current value actually generated in the detected device.

[0069] For example, a first control signal is input to make the self-test circuit enter the first conduction state. At this time, the total resistance value of the self-test circuit is the first value, and its input voltage is a certain value. Then, according to Ohm's law, the residual current calculation value in the first conduction state can be obtained, and the calculated value is compared with the detection value to determine whether the detection value is consistent with the calculated value. If they are consistent, the first control signal input is maintained, and the second control signal input is triggered to make the self-test circuit enter the second conduction state. Its total resistance value changes to the second value, and its input voltage remains unchanged. According to Ohm's law, the residual current calculation value in the second conduction state can be obtained. The first ratio between the residual current detection value in the first conduction state and the residual current detection value in the second conduction state is calculated, and the second ratio between the residual current calculation value in the first conduction state and the residual current calculation value in the second conduction state is calculated, and then the first ratio and the second ratio are determined to be consistent, so as to determine whether the detection ratio of the residual current detection device is abnormal. In this embodiment, consistency means the same, or the error is within a preset range.

[0070] The self-test circuit of this embodiment inputs a detection voltage through the first terminal 1; connects to the reference ground through the second terminal 2 to form a current loop with the first terminal 1; inputs a first control signal through the third terminal 3 to make the self-test circuit enter a first conduction state to detect whether a residual current is generated and determine whether the value of the residual current is abnormal; and inputs a second control signal through the fourth terminal 4 on the basis of maintaining the input of the first control signal at the third terminal 3 to make the self-test circuit enter a second conduction state to detect whether the detection ratio of the residual current detection device is abnormal. Before the residual current detection device is officially used, a self-test can be performed first to ensure the accuracy of the detection result and avoid affecting the normal operation of the converter due to the inability of the residual current detection device to accurately measure the residual current.

[0071] Example 2

[0072] This embodiment provides another self-test circuit. Figure 2 is a structural diagram of a self-test circuit according to an embodiment of the present invention, such as Figure 2 As shown, the self-test circuit includes: a first detection branch 11, which is arranged between the first terminal 1 and the second terminal 2, and is turned on under the control of a first control signal, so that the self-test circuit enters a first conduction state; a second detection branch 12, which is connected in parallel with the first detection branch 11, and after the first detection branch 11 is turned on, the second detection branch 12 is turned on under the control of a second control signal, so that the self-test circuit enters a second conduction state. By controlling the conduction states of the first detection branch 11 and the second detection branch 12, it is possible to make the self-test circuit enter the first conduction state or the second conduction state, so that the self-test circuit has different total resistance values, and thus different residual current values ​​can be detected to determine whether the residual current value is abnormal, and whether the detection ratio is abnormal. Wherein the first detection branch 11 and the second detection branch 12 include at least one resistor to realize the switching of different resistance values. At least one resistor in the first detection branch 11 or the second detection branch 12 is a variable resistor, so as to change the total resistance value and perform multiple measurements. In this embodiment, the first detection branch 11 includes a first resistor R1 , and the second detection branch 12 includes a second resistor R2 , and the second resistor R2 is a variable resistor.

[0073] To realize the control of the conduction state of the first detection branch 11 and the second detection branch 12, as Figure 2The self-test circuit shown above includes: a first switch Q1, which is arranged between the connection point of the first detection branch 11 and the second detection branch 12 and the second terminal 2, and is used to be turned on under the control of a first control signal, thereby controlling the first detection branch 11 to be turned on; and a second switch Q2, which is arranged on the second detection branch 12, and is used to be turned on under the control of a second control signal on the basis of the first switch Q1 being turned on, thereby controlling the second detection branch 12 to be turned on as well. The first switch Q1 and the second switch Q2 are used to control the first detection branch 11 to be turned on alone, or the first detection branch 11 and the second detection branch 12 to be turned on at the same time, so as to control different resistors to be turned on, thereby controlling the switching of the total resistance value of the self-test circuit.

[0074] The current residual current detection devices generally include two types. One is a threading type residual current detection device, which requires a detection wire to pass through the inside. During detection, a detection voltage is input from the first terminal 1 to make current pass through the inside of the detection wire, then a magnetic field is generated around the detection wire, and the residual current detection device detects the generated induced current, thereby achieving the purpose of residual current detection; the other is a built-in wire type on-board residual current detection device, which has a detection wire inside. A certain value of voltage is input at one end of the detection wire, and the other end is connected to the detection voltage input terminal in the circuit to be tested. When the circuit to be tested is energized, current passes through the detection wire of the residual current detection device, and a magnetic field is generated around the detection wire. The residual current detection device detects the generated induced current, thereby achieving the purpose of detecting the residual current.

[0075] The self-test circuit of this embodiment can be applied to a threading type residual current detection device. When applied to a self-contained wire type on-board residual current detection device, the self-test circuit further includes: a third switch K, which is arranged between the connection point of the first detection branch 11 and the second detection branch 12 and the first terminal 1; and a fifth terminal, which is used to input a third control signal to turn on the third switch K. Whether the self-test circuit is powered on is controlled by turning off or on the third switch K.

[0076] The self-test circuit of this embodiment can also be applied to a threading type residual current detection device. When applied to a threading type residual current detection device, the self-test circuit also includes: a first wiring terminal J1-1 and a second wiring terminal J1-2, the first wiring terminal J1-1 and the second wiring terminal J1-2 are arranged between the connection point of the first detection branch 11 and the second detection branch 12 and the first terminal 1, the first wiring terminal J1-1 is used to connect the first end of the detection wire of the residual current detection device, and the second wiring terminal J1-2 is used to connect the second end of the detection wire.

[0077] Figure 3FIG. 1 is a structural diagram of a self-test circuit according to another embodiment of the present invention. After the first control signal or the second control signal is input, the voltage value of the first control signal or the second control signal may not reach the turn-on voltage of the first switch Q1 or the second switch Q2, so that the first switch Q1 or the second switch Q2 cannot be turned on smoothly. To solve the above problem, Figure 3 As shown, the self-test circuit also includes: a conversion module, which is used to convert the first control signal input from the third terminal 3 to obtain a first conversion signal, and the first conversion signal is used to control the self-test circuit to enter the first conduction state; the conversion module is also used to convert the second control signal input from the fourth terminal 4 to obtain a second conversion signal, and the second conversion signal is used to control the self-test circuit to enter the second conduction state. Specifically, if the voltage value of the first control signal or the second control signal is too low, the above-mentioned conversion module can increase the voltage value of the first control signal or the second control signal by boosting, which can ensure that after the first control signal or the second control signal is input, the first switch Q1 or the second switch Q2 is smoothly turned on.

[0078] Example 3

[0079] This embodiment provides a self-test method, which is applied to the self-test circuit in the above embodiment. Figure 4 Flow chart of a self-checking method according to an embodiment of the present invention. Figure 4 As shown, the method includes:

[0080] S101, triggering a first control signal input to enable the self-detection circuit to enter a first conduction state to determine whether the detection accuracy of the residual current detection device is abnormal.

[0081] After the self-test circuit enters the first conduction state, the resistance of the self-test circuit is a first value. The residual current calculation value can be obtained based on the first value and the detection voltage, and compared with the residual current detection value, it can be determined whether the detection accuracy of the residual current detection device is abnormal.

[0082] S102, if the detection accuracy of the residual current detection device is normal, triggering the second control signal input on the basis of maintaining the first control signal input, so that the self-detection circuit enters the second conduction state to determine whether the detection ratio of the residual current detection device is abnormal.

[0083] In the above step S102, the residual current detection value and calculated value in the first conduction state have been obtained. By triggering the second control signal input, the self-test circuit enters the second conduction state, and another residual current detection value and calculated value can be obtained. By comparing the ratio between the two sets of calculated values ​​and detection values, it can be determined whether the detection ratio of the residual current detection device is abnormal.

[0084] The self-test method of this embodiment triggers the first control signal input to make the self-test circuit enter the first conduction state to determine whether the detection accuracy of the residual current detection device is abnormal; if the detection accuracy of the residual current detection device is normal, the second control signal input is triggered on the basis of maintaining the first control signal input to make the self-test circuit enter the second conduction state to determine whether the detection ratio of the residual current detection device is abnormal. Before the residual current detection device is officially used, a self-test can be performed first to ensure the accuracy of the detection result and avoid affecting the normal operation of the converter due to the inability of the residual current detection device to accurately measure the residual current.

[0085] Example 4

[0086] This embodiment provides another self-checking method. On the basis of the above embodiment, it is determined whether the detection accuracy of the residual current detection device is abnormal, specifically including: determining whether the residual current detection value is consistent with the calculated value; if so, determining that the detection accuracy of the residual current detection device is normal; if not, determining that the detection accuracy of the residual current detection device is abnormal. Determining whether the detection ratio of the residual current detection device is abnormal specifically includes: according to the current calculation formula, respectively calculating the first ratio between the residual current detection value in the first conduction state and the residual current detection value in the second conduction state, and the second ratio between the residual current calculated value in the first conduction state and the residual current detection value in the second conduction state; determining whether the first ratio is consistent with the second ratio; if so, determining that the detection ratio of the residual current detection device is normal; if not, determining that the detection ratio of the residual current detection device is abnormal. Wherein, consistent means the same, or the error is within a preset range. Through the above scheme, it is possible to accurately determine whether the detection accuracy of the residual current detection device is abnormal and whether the detection ratio is abnormal.

[0087] For example, when designing the circuit, it is set that: the first detection branch includes a first resistor R1, the resistance of the first resistor R1 is 470 ohms, the second detection branch includes a second resistor R2, the resistance of the second resistor R2 is 470 ohms. The detection voltage is VCC, and the saturation voltage of the first switch is V CE , when only the first resistor R1 is connected to the loop, the detection voltage VCC passes through the first resistor R1 and the first switch to the reference ground, forming a current loop. The current of the loop can be obtained by Ohm's law:

[0088]

[0089] When the resistors R1 and R4 are connected in parallel to the circuit, the detection voltage VCC passes through the parallel circuit formed by the first resistor R1 and the second resistor R2 and the first switch to the reference ground to form a current loop. According to Ohm's law, the current in this circuit is:

[0090]

[0091] Through the above solution, the residual current calculation values ​​in the first conduction state and the second conduction state are obtained.

[0092] In the specific implementation process, the residual current may not be detected. If the residual current is not detected, it means that the residual current detection device is abnormally turned on, and a short circuit or open circuit may occur inside. Therefore, before determining whether the detection accuracy of the residual current detection device is abnormal, the method also includes: determining whether the residual current is detected; if not, determining that the residual current detection device is abnormally turned on; if yes, triggering the determination of whether the detection accuracy of the residual current detection device is abnormal. Through the above scheme, it is possible to detect whether the residual current detection device is turned on normally. When the conduction is abnormal and a short circuit or open circuit may occur inside, it can be discovered and processed in time to avoid inaccurate detection results when it is officially used.

[0093] In the specific implementation process, the first control signal input is triggered to make the self-test circuit enter the first conduction state, including: triggering the first control signal input to turn on the first switch, thereby controlling the first detection branch to turn on, so that the self-test circuit enters the first conduction state. On the basis of maintaining the first control signal input, the second control signal input is triggered to make the self-test circuit enter the second conduction state, including: triggering the second control signal input to turn on the second switch, thereby controlling the second detection branch to turn on, so that the self-test circuit enters the second conduction state. Through the first detection signal and the second detection signal, the turn-on timing of the first switch and the second switch can be accurately controlled, thereby accurately switching the conduction state of the entire self-test circuit.

[0094] The self-test circuit of this embodiment can be applied to a threading type residual current detection device. When applied to a self-contained wire type on-board residual current detection device, before triggering the first control signal input, the method further includes: triggering the third control signal input to turn on the third switch; wherein the third switch is arranged between the connection point of the first detection branch and the second detection branch and the first terminal of the self-test circuit. By setting the third switch and the third control signal for controlling the conduction of the third switch, the conduction state of the entire self-test circuit can be controlled.

[0095] Example 5

[0096] This embodiment provides a self-test circuit, as mentioned above Figure 2As shown in , the self-test circuit includes: 5 external terminals, namely: a first terminal 1, for inputting an external detection voltage VCC or a detection voltage Test_Out output by a residual current detection device, a second terminal 2, for connecting a reference ground GND, a third terminal 3, for inputting a first control signal S1, a fourth terminal 4, for inputting a second control signal S2, and a fifth terminal 5 for inputting a third control signal S3. The first terminal 1 has multiple functions: when a threading type on-board residual current detection device is selected, the first terminal 1 inputs an external detection voltage VCC, and the first terminal J1_1 and the second terminal J1_2 in the self-test circuit are respectively connected to the two ends of the detection wire of the residual current detection device, and the first control signal S1 and the second control signal S2 are triggered in sequence to realize the self-test function; when a self-contained wire type on-board residual current detection device is selected, the first terminal 1 inputs the detection voltage Test_Out output by the residual current detection device, and the third control signal S3, the first control signal S1, and the second control signal S2 are triggered in sequence to realize the self-test function. The first control signal S1 is used to control the on and off of the first switch; the second control signal S2 is used to control the on or off of the second switch; the third control signal S3 controls the on and off of the third switch. The calculated value of the residual current is determined by the first resistor R1 and the second resistor R2, because the resistance values ​​of the first resistor R1 and the second resistor R2 are known.

[0097] The above self-test circuit is independently packaged into a module, and plugging and unplugging is achieved by simply installing the terminals of the output detection voltage, ground voltage, first control signal S1, second control signal S2, and third control signal S3 on the control mainboard of the converter, and the component is installed according to the actual application requirements. The module is applied to the intelligent converter to solve the problem of frequent misprotection caused by abnormal function of the residual current detection device or no protection due to excessive residual current, and prevent safety accidents.

[0098] This embodiment also provides a self-test method, which is applied to a threading type on-board residual current detection device. Figure 5 is a flow chart of a detection method according to another embodiment of the present invention, Figure 5 As shown, the method includes:

[0099] S11, control the converter to power on.

[0100] S12, triggering a first control signal to turn on the first switch, wherein the first control signal is a high level signal.

[0101] S13, determine whether residual current is detected, if not, execute step S14, if yes, execute step S15. After the first switch is turned on, the detection voltage VCC forms a loop through the first resistor and the first switch to the reference ground, that is, residual current should flow through the residual current detection device. If there is residual current, it indicates that the device functions normally. If no residual current is detected, the main control circuit reports a fault, the converter does not operate, and the designer is prompted to troubleshoot the problem.

[0102] S14, reporting abnormal conduction of the residual current detection device.

[0103] S15, determine whether the residual current detection value is consistent with the calculated value; if not, execute step S16; if yes, execute step S17. After the first switch is turned on, the calculated value of the residual current can be pre-calculated by the known resistance value of the first resistor. If the residual current detection value is consistent with the calculated value, it means that the detection accuracy of the residual current detection device is normal, otherwise, the detection accuracy of the residual current detection device is abnormal. Among them, consistent means the same or the error is within a preset range.

[0104] S16, reporting that the detection accuracy of the residual current detection device is abnormal. After determining that the detection accuracy of the residual current detection device is abnormal, the converter is controlled to temporarily stop running and a fault is reported.

[0105] S17, triggering a control signal to turn on the second switch, wherein the second control signal is a high level signal.

[0106] S18, determine whether the residual current detection ratio is abnormal; if yes, execute step S19; if not, execute step S110. After the second switch is turned on, the first resistor and the second resistor are connected in parallel, the resistance decreases, and the residual current flowing through the residual current detection device will increase. The residual current value calculation value at this time can be pre-calculated by the known resistance values ​​of the first resistor and the second resistor, and compared with the residual current detection value detected when the first switch is turned on alone, it can be determined whether the detection ratio of the residual current detection device is abnormal; if abnormal, report that the detection ratio of the residual current detection device is abnormal; if normal, determine that the residual current detection device is working normally, stop outputting the first control signal and the second control signal, and complete the self-check. After the residual current detection device completes the self-check, the converter can be controlled to start and run normally.

[0107] For example, when designing the circuit, the resistance of the first resistor is set to 470 ohms, and the resistance of the second resistor is set to 470 ohms. The detection voltage is VCC, and the saturation voltage of the first switch is V CE , when only the first resistor is connected to the loop, the detection voltage VCC passes through the first resistor and the first switch to the reference ground, forming a current loop. The current of the loop can be obtained by Ohm's law:

[0108]

[0109] When the first resistor and the second resistor are connected in parallel to the circuit, the detection voltage VCC passes through the parallel circuit formed by the first resistor and the second resistor and the first switch to the reference ground to form a current loop. According to Ohm's law, the current in this circuit is:

[0110]

[0111] Through the above solution, the residual current calculation value when the first switch is turned on alone and the first switch and the second switch are turned on simultaneously is obtained.

[0112] S19, reporting that the detection ratio of the residual current detection device is abnormal.

[0113] S20, stop outputting the first control signal and the second control signal, and complete the self-check.

[0114] This embodiment also provides another self-test method, which is applied to a self-contained wire type on-board residual current detection device. Figure 6 is a flow chart of a detection method according to another embodiment of the present invention, as shown in Figure 6 As shown, the method includes:

[0115] S21, control the converter to power on.

[0116] S22, triggering the third control signal to turn on the third switch.

[0117] S23, triggering a first control signal to turn on the first switch, wherein the first control signal is a high level signal.

[0118] S24, determine whether residual current is detected, if not, execute step S25, if yes, execute step S26. After the first switch is turned on, the detection voltage VCC forms a loop through the first resistor and the first switch to the reference ground, that is, residual current should flow through the residual current detection device. If there is residual current, it indicates that the device functions normally. If no residual current is detected, the main control circuit reports a fault, the converter does not operate, and the designer is prompted to troubleshoot the problem.

[0119] S25, reporting that the residual current detection device is abnormally conducting.

[0120] S26, determine whether the residual current detection value is consistent with the calculated value; if not, execute step S27; if yes, execute step S28. After the first switch is turned on, the calculated value of the residual current can be pre-calculated by the known resistance value of the first resistor. If the residual current detection value is consistent with the calculated value, it means that the detection accuracy of the residual current detection device is normal, otherwise, the detection accuracy of the residual current detection device is abnormal. Among them, consistent means the same or the error is within a preset range.

[0121] S27, reporting that the detection accuracy of the residual current detection device is abnormal. After determining that the detection accuracy of the residual current detection device is abnormal, the converter is controlled to temporarily stop running and a fault is reported.

[0122] S28, triggering a control signal to turn on the second switch, wherein the second control signal is a high level signal.

[0123] S29, determine whether the residual current detection ratio is abnormal; if yes, execute step S210; if not, execute step S211. After the second switch is turned on, the first resistor and the second resistor are connected in parallel, the resistance decreases, and the residual current flowing through the residual current detection device will increase. The residual current value at this time can be calculated in advance by the known resistance values ​​of the first resistor and the second resistor, and compared with the residual current detection value detected when the first switch is turned on alone, it can be determined whether the detection ratio of the residual current detection device is abnormal; if abnormal, report that the detection ratio of the residual current detection device is abnormal; if normal, determine that the residual current detection device is working normally, stop outputting the first control signal and the second control signal, and complete the self-check. After the residual current detection device completes the self-check, the converter can be controlled to start and run normally.

[0124] S210, reporting that the detection ratio of the residual current detection device is abnormal.

[0125] S211, stop outputting the first control signal and the second control signal, and complete the self-check.

[0126] The self-checking method of this embodiment can solve the problem of frequent misprotection or failure to protect due to excessive residual current caused by malfunction of the residual current detection device, thereby preventing safety accidents.

[0127] Example 6

[0128] This embodiment provides a residual current detection device, including the above-mentioned self-test circuit, which is used to test the residual current detection device before formal use to ensure the accuracy of the detection result of the residual current detection device.

[0129] Example 7

[0130] This embodiment provides a converter, including the above-mentioned residual current detection device, which is used to accurately detect the residual current of the converter to ensure safe and stable operation of the converter.

[0131] Example 8

[0132] This embodiment provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the above self-checking method is implemented.

[0133] The device embodiments described above are merely illustrative, wherein the modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical modules, i.e., they may be located in one place or distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0134] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0135] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A self-test circuit, characterized in that: The self-test circuit is applied to a residual current detection device, and the self-test circuit comprises: A first terminal for inputting a detection voltage; The second terminal is connected to the reference ground; A third terminal is used to input a first control signal to enable the self-detection circuit to enter a first conduction state to detect whether the detection accuracy of the residual current detection device is abnormal; The fourth terminal inputs the second control signal on the basis of maintaining the first control signal inputted by the third terminal, so that the self-test circuit enters the second conduction state, so as to detect whether the detection ratio of the residual current detection device is abnormal; wherein, the detection ratio is the proportional relationship between the residual current detection value obtained by the residual current detection device and the residual current value actually generated in the detected device; detecting whether the detection ratio of the residual current detection device is abnormal, comprising: respectively calculating a first ratio between the residual current detection value in the first conduction state and the residual current detection value in the second conduction state, and a second ratio between the residual current calculation value in the first conduction state and the residual current calculation value in the second conduction state; judging whether the first ratio is consistent with the second ratio; if so, judging that the detection ratio of the residual current detection device is normal; if not, judging that the detection ratio of the residual current detection device is abnormal.

2. The circuit according to claim 1, characterized in that The self-test circuit comprises: A first detection branch, arranged between the first terminal and the second terminal, configured to be turned on under the control of the first control signal so that the self-test circuit enters a first conduction state; The second detection branch is connected in parallel with the first detection branch, and is used to be turned on under the control of the second control signal after the first detection branch is turned on, so that the self-test circuit enters a second conduction state.

3. The circuit according to claim 2, characterized in that The first detection branch and the second detection branch include at least one resistor.

4. The circuit according to claim 3, characterized in that At least one resistor in the first detection branch or the second detection branch is a variable resistor.

5. The circuit according to claim 2, characterized in that The self-test circuit also includes: A first switch is provided between a connection point between the first detection branch and the second detection branch and the second terminal, and is used to be turned on under the control of the first control signal, thereby controlling the first detection branch to be turned on; The second switch is arranged on the second detection branch, and is used to be turned on under the control of the second control signal on the basis of the first switch being turned on, thereby controlling the second detection branch to be turned on.

6. The circuit according to claim 2, characterized in that The self-test circuit also includes: A third switch is provided between a connection point between the first detection branch and the second detection branch and the first terminal; The fifth terminal is used to input a third control signal to turn on the third switch.

7. The circuit according to claim 2, characterized in that The self-test circuit also includes: A first wiring terminal and a second wiring terminal, wherein the first wiring terminal and the second wiring terminal are arranged between the connection point of the first detection branch and the second detection branch and the first terminal, the first wiring terminal is used to connect the first end of the detection wire of the residual current detection device, and the second wiring terminal is used to connect the second end of the detection wire.

8. The circuit according to claim 1, characterized in that The self-test circuit also includes: a conversion module, used for converting a first control signal inputted from a third terminal to obtain a first conversion signal, wherein the first conversion signal is used for controlling the self-test circuit to enter a first conduction state; The conversion module is further used for converting a second control signal inputted from the fourth terminal to obtain a second conversion signal, wherein the second conversion signal is used for controlling the self-test circuit to enter a second conduction state.

9. A residual current detection device, characterized in that: The self-test circuit comprises the self-test circuit as claimed in any one of claims 1 to 8.

10. A converter, characterized in that: Includes the residual current detection device as described in claim 9.

11. A self-test method, applied to the self-test circuit according to any one of claims 1 to 8, characterized in that: The method comprises: triggering a first control signal input to cause the self-test circuit to enter a first conduction state, so as to determine whether the detection accuracy of the residual current detection device is abnormal; If the detection accuracy of the residual current detection device is normal, then on the basis of maintaining the first control signal input, triggering the second control signal input, so that the self-test circuit enters the second conduction state, so as to determine whether the detection ratio of the residual current detection device is abnormal; wherein, determining whether the detection ratio of the residual current detection device is abnormal includes: respectively calculating a first ratio between a residual current detection value in a first conduction state and a residual current detection value in a second conduction state, and a second ratio between a residual current calculation value in the first conduction state and a residual current calculation value in the second conduction state; determining whether the first ratio is consistent with the second ratio; If yes, it is determined that the detection ratio of the residual current detection device is normal; If not, it is determined that the detection ratio of the residual current detection device is abnormal.

12. The method according to claim 11, characterized in that Determine whether the detection accuracy of the residual current detection device is abnormal, including: Determine whether the residual current detection value is consistent with the calculated value; If yes, it is determined that the detection accuracy of the residual current detection device is normal; If not, it is determined that the detection accuracy of the residual current detection device is abnormal.

13. The method according to claim 11, characterized in that Before determining whether the detection accuracy of the residual current detection device is abnormal, the method further includes: Determine whether residual current is detected; If not, it is determined that the residual current detection device is abnormally conductive; If yes, it triggers the determination of whether the detection accuracy of the residual current detection device is abnormal.

14. The method according to claim 11, characterized in that Triggering a first control signal input to enable the self-test circuit to enter a first conduction state includes: The first control signal input is triggered to turn on the first switch, thereby controlling the first detection branch to turn on, so that the self-test circuit enters a first conduction state.

15. The method according to claim 11, characterized in that Triggering the second control signal input on the basis of maintaining the first control signal input so as to make the self-test circuit enter the second conduction state includes: The second control signal input is triggered to turn on the second switch, thereby controlling the second detection branch to turn on, so that the self-test circuit enters the second conduction state.

16. The method according to claim 11, characterized in that Before triggering the first control signal input to make the self-test circuit enter the first conducting state, the method further includes: The third control signal input is triggered to turn on the third switch; wherein the third switch is arranged between the connection point of the first detection branch and the second detection branch and the first terminal of the self-detection circuit.

17. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method according to any one of claims 11 to 16 is implemented.

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