Leakage protection self-checking circuit for direct current switch device, leakage protection assembly and switch device

Abstract

The embodiment of the utility model provides an electric leakage protection self-checking circuit for a direct-current switching device, an electric leakage protection assembly and the switching device. The leakage protection self-checking circuit comprises a control signal generation circuit which comprises a first output side and a second output side and is suitable for alternately outputting control electric signals with high level and low level on the first output side and the second output side respectively; the full-bridge circuit is coupled to the electric leakage detection circuit of the direct-current switching device and comprises a first branch circuit which is coupled to the first output side so as to be switched on under the condition that the first output side outputs a high-level control electric signal, so that the full-bridge circuit generates forward electric leakage current; and the second branch circuit is coupled to the second output side and is switched on under the condition that the second output side is a high-level control electric signal, so that the full-bridge circuit generates negative leakage current. Therefore, the problem that the inherent leakage current and the test leakage current in the direct-current switch device are offset can be avoided.

Description

TECHNICAL FIELD

[0001] Example embodiments of the present disclosure generally relate to the field of switching devices, and in particular, to a leakage protection self-checking circuit, a leakage protection assembly, and a switching device for a direct current switching device. BACKGROUND

[0002] In a direct current power supply system, in order to ensure the safety and reliability of the system, a leakage protection device (also known as a switching device) is usually equipped. When a leakage fault occurs in the system, the leakage protection device can detect the leakage current and quickly cut off the power supply to prevent electric shock accidents or equipment damage. In order to verify whether the leakage protection device can work normally when an actual leakage fault occurs, it is necessary to perform periodic self-checking tests on the leakage protection device. This test method is called "RCD test", which generates a test leakage current by simulating a leakage condition, so that the leakage protection device senses the current and triggers a response to detect the effectiveness of its function. However, the existing leakage protection device has the problem that the inherent leakage current in the direct current switching device and the test leakage current offset each other and affect the RCD test. SUMMARY

[0003] The purpose of the present disclosure is to provide a leakage protection self-checking circuit, a leakage protection assembly, and a switching device for a direct current switching device, to at least partially solve the above-mentioned problems and / or other potential problems existing in conventional switching devices.

[0004] In a first aspect of the present disclosure, a leakage protection self-checking circuit and a switching device for a direct current switching device are provided. The leakage protection self-checking circuit comprises: a control signal generation circuit comprising a first output side and a second output side, and adapted to alternately output control electrical signals with high and low levels at the first output side and the second output side, respectively; and a full-bridge circuit coupled to a leakage detection circuit of the direct current switching device, and comprising: a first branch coupled to the first output side to conduct in the case that the first output side outputs a high level control electrical signal, to make the full-bridge circuit generate a positive leakage current; and a second branch coupled to the second output side to conduct in the case that the second output side is a high level control electrical signal, to make the full-bridge circuit generate a negative leakage current.

[0005] In embodiments according to the present disclosure, the conducting path of the full-bridge circuit is switched by setting different levels of the control signal in the leakage protection self-checking circuit, thereby switching between the first branch and the second branch. In this way, test leakage currents of different directions can be generated to effectively trigger the leakage detection circuit, and the accurate leakage protection self-checking function is achieved. Further, when the first output side is high and the second output side is low, the first branch is turned on to generate a positive leakage current; when the first output side is low and the second output side is high, the second branch is turned on to generate a negative leakage current. In this way, positive and negative artificial test leakage currents can be formed in the DC switching device, and different direction leakage conditions can be simulated to ensure the integrity of the leakage protection self-checking. Other benefits will be described below in conjunction with the corresponding embodiments.

[0006] In some embodiments, the first branch includes a first switch and a fourth switch, both coupled to the first output side, and adapted to make the full-bridge circuit generate a positive leakage current, and the second branch includes a second switch and a third switch, both coupled to the second output side, and adapted to make the full-bridge circuit generate a negative leakage current.

[0007] In some embodiments, the gate of the fourth switch is coupled to the first output side of the control signal generation circuit, and the gate of the third switch is coupled to the second output side of the control signal generation circuit.

[0008] In some embodiments, the source of the first switch and the source of the second switch are coupled, the source of the third switch and the source of the fourth switch are coupled, and the drain of the first switch and the drain of the third switch are coupled, and the drain of the second switch and the drain of the fourth switch are coupled.

[0009] In some embodiments, the leakage protection self-checking circuit further includes a fifth switch, the gate of the fifth switch being coupled to the first output side of the control signal generation circuit, the drain of the fifth switch being coupled to the gate of the first switch, the source of the fifth switch being grounded, and being adapted to be turned on when the control signal of the first output side is high; and a sixth switch, the gate of the sixth switch being coupled to the second output side of the control signal generation circuit, the drain of the sixth switch being coupled to the gate of the second switch, the source of the sixth switch being grounded, and being adapted to be turned on when the control signal of the second output side is high.

[0010] In some embodiments, the first switch and the second switch are P-type metal oxide semiconductor field effect transistors, and the third switch, the fourth switch, the fifth switch and the sixth switch include N-type metal oxide semiconductor field effect transistors.

[0011] In some embodiments, the leakage protection self-checking circuit further includes a self-checking winding circuit coupled to the output side of the full-bridge circuit, and adapted to adjust the size of the control signal.

[0012] In some embodiments, the leakage protection self-checking circuit further comprises a power supply circuit. The positive pole of the power supply circuit is coupled to the source of the first switch and the second switch, and the source of the third switch and the source of the fourth switch are grounded, adapted to supply power to the leakage protection self-checking circuit to generate the leakage current.

[0013] In a second aspect of the present disclosure, a leakage protection assembly for a direct current switching device is provided. The leakage protection assembly comprises: a leakage protection self-checking circuit according to the first aspect described above; and a leakage detection circuit coupled to the self-checking winding circuit of the leakage protection self-checking circuit, adapted to generate a trip signal in the case that the leakage current generated by the leakage protection self-checking circuit meets a predetermined condition, or the leakage current generated by the circuit connected to the direct current switching device meets a predetermined condition.

[0014] In a third aspect of the present disclosure, a switching device is provided. The switching device comprises: a leakage protection assembly according to the second aspect described above; and a trip assembly coupled to the leakage detection circuit of the leakage protection self-checking circuit to trip based on the trip signal generated by the leakage detection circuit.

[0015] It should be understood that the contents described in this part of the content are not intended to limit the key features or important features of the embodiments of the present disclosure, nor are they used to limit the scope of the present disclosure. Other features of the present disclosure will become apparent through the following description. BRIEF DESCRIPTION OF DRAWINGS

[0016] The above and other features, advantages and aspects of embodiments of the present disclosure will become more apparent by describing in detail some embodiments thereof with reference to the annexed drawings in which:

[0017] Figure 1 a schematic diagram of a leakage protection self-checking circuit of a switching device according to some embodiments of the present disclosure is shown; and

[0018] Figure 2 a sequence diagram of a RCD test self-checking process for a direct current switching device according to some embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0019] Embodiments of the present disclosure will be described below in greater detail with reference to the accompanying drawings. Although certain embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms, and should not be interpreted as being limited to the embodiments set forth herein, rather, these embodiments are provided to make the present disclosure more thorough and complete. It should be understood that the drawings and embodiments of the present disclosure are only for exemplary purposes, and are not intended to limit the scope of protection of the present disclosure.

[0020] In the description of embodiments of the disclosure, the term "comprising" and its conjugations should be understood as open-ended, i.e., "including but not limited to". The term "based on" should be understood as "based at least in part on". The term "one embodiment" or "an embodiment" should be understood as "at least one embodiment". The term "some embodiments" should be understood as "at least some embodiments". Other explicit and implicit definitions can also be included below. The terms "first", "second", etc. can refer to different or the same objects. Other explicit and implicit definitions can also be included below.

[0021] As briefly mentioned above, the existing leakage protection device has the problem of mutual offset between the inherent leakage current and the test leakage current. Specifically, in the RCD test, the self-checking circuit of the switch device generates a specific test leakage current (also known as self-checking leakage current), which flows through the leakage detection circuit of the switch device to confirm whether the leakage detection circuit can correctly identify the leakage situation and trigger the protection action. In addition, the leakage protection self-checking test function needs to be manually executed by the user regularly to ensure the continuous reliability of the leakage protection device.

[0022] However, in actual application, there is already an inherent leakage current in the direct current switch device, which comes from the normal leakage current of the switch device or other non-faulty leakage current in the system. When the direction of this inherent leakage current is opposite to that of the test leakage current, the two currents will offset each other. This current offset will result in a lower synthetic leakage current than the current value required for normal test, so that the leakage detection circuit cannot sense a large enough leakage current, resulting in the failure of the leakage protection device to trigger. Due to the failure to reach the necessary leakage current threshold, the test will miss the situation, which cannot effectively verify the function of the leakage protection device (also known as switch device), thereby affecting the safety of the system.

[0023] In order to solve or at least partially solve the above-mentioned problems or other potential problems of the switch device of the existing scheme, embodiments of the disclosure provide a leakage protection self-checking circuit, a leakage protection assembly and a switch device scheme for a direct current switch device. The leakage protection self-checking circuit includes a control signal generation circuit and a full-bridge circuit. The control signal generation circuit includes a first output side and a second output side, and can alternately output high-level and low-level control signals at the 2 output sides respectively, so as to control the conduction path of the full-bridge circuit.

[0024] The full-bridge circuit includes a first branch and a second branch. The first branch and the second branch are coupled to the leakage detection circuit of the direct current switch device, and the first branch is coupled to the first output side and the second branch is coupled to the second output side to realize the selection of different conduction paths.

[0025] In a specific operation, when the first output side of the control signal generation circuit is high and the second output side is low, the first branch of the full-bridge circuit is turned on to generate a positive leakage current; on the contrary, when the first output side is low and the second output side is high, the second branch of the full-bridge circuit is turned on to generate a negative leakage current. In this way, the leakage protection self-checking circuit can automatically switch the direction of the leakage current under different level control signals, realize the simulation detection of the positive and negative bidirectional leakage, and ensure the effectiveness and reliability of the leakage protection function.

[0026] In this way, the anti-interference and accuracy of the leakage protection self-checking circuit are improved. In other words, when there is an inherent leakage current opposite to the direction of the self-checking leakage current (also referred to as the test leakage current) in the direct current switching device, the leakage protection self-checking circuit in the embodiment of the present disclosure generates a bidirectional leakage current by switching the conduction direction of the two branches, avoids the interference of the inherent leakage current opposite in direction to the self-checking process, and thus ensures the accuracy of the self-checking result.

[0027] Figure 1 A schematic diagram of a leakage protection self-checking circuit 100 of a switching device according to some embodiments of the present disclosure is shown. Figure 2 A sequence diagram of an RCD test self-checking process for a direct current switching device according to some embodiments of the present disclosure is shown. The example structure and working process of the leakage protection self-checking circuit 100 for a direct current switching device in an electronic device will be described below in conjunction with Figures 1 to 2 The switching device according to the embodiments of the present disclosure can include a direct current circuit breaker, or any other appropriate device other than a circuit breaker. Hereinafter, the concept of the present disclosure will be mainly described taking the switching device as a circuit breaker as an example. It should be understood that the concept is similar for the case where the switching device is other devices, which will not be described separately hereinafter.

[0028] The switching device according to the embodiments of the present disclosure includes a leakage protection component and a tripping component. The tripping component is coupled to the leakage detection circuit of the leakage protection component, and can automatically trigger tripping to cut off the circuit when a leakage condition is detected, to ensure the safety of the direct current switching device. Specifically, the leakage protection component is used to detect the leakage condition in the system and also to verify the effectiveness of the leakage detection function. The leakage protection component includes a test circuit for simulating a leakage fault, which generates a test leakage current by periodic or manual excitation, so that the leakage detection circuit can sense the test current and respond in the case of normal leakage protection function.

[0029] In some embodiments, the leakage protection component and the tripping component can be two independent parts, and a switch device is formed by assembling the two parts. The leakage protection component and the tripping component can also be integrated into one whole body, and the embodiments of the present disclosure are not limited in this regard.

[0030] Further, the tripping component is coupled to a leakage detection circuit of the leakage protection component, and is adapted to trigger a tripping action when the leakage detection circuit senses an abnormal leakage current. Specifically, when the leakage detection circuit detects that the test current or the actual leakage current reaches a preset threshold, the tripping component will immediately respond to cut off the circuit, ensuring the safety of the DC switch device and the user. Therefore, the switch device not only can cut off the circuit to protect the system in the case of normal leakage, but also provides a self-checking function through the leakage protection component, ensuring the reliability and accuracy of the leakage detection.

[0031] Further, the leakage detection circuit of the leakage protection component is coupled to the output end of the self-checking winding circuit 150 of the leakage protection self-checking circuit 100, and is adapted to generate a tripping signal when the leakage current generated by the leakage protection self-checking circuit 100 meets a predetermined condition or the leakage current generated by the circuit connected to the DC switch device meets a predetermined condition. In other words, the leakage detection circuit is used to monitor the size of the leakage current in real time, and compare it with a preset leakage protection threshold. When the detected leakage current reaches or exceeds the leakage protection threshold, the leakage detection circuit will generate a tripping signal and trigger a tripping protection action, such as starting a relay or a circuit breaker to cut off the power supply, which can ensure that the switch device can quickly respond and cut off the power supply when a leakage occurs, thereby avoiding safety accidents. For example, the leakage protection threshold can be set to 100 mA, and the embodiments of the present disclosure are not limited in this regard.

[0032] The specific structure of the leakage protection self-checking circuit 100 will be described below in combination with Figure 1 and Figure 2 In the embodiments of the present disclosure, the leakage protection self-checking circuit 100 generally includes a control signal generation circuit and a full-bridge circuit. Through the cooperation of the control signal generation circuit and the full-bridge circuit, positive and negative leakage currents are generated to test whether the leakage protection function of the system is working normally.

[0033] Further, the control signal generation circuit includes a first output side 110 and a second output side 120 for generating signals to control the conduction state of the full-bridge circuit. The control signal generation circuit is adapted to alternately output control signals with high and low levels at the two output sides respectively, so as to realize the selection of different circuit paths. The control signal generation circuit can control the conduction state of different branches in the full-bridge circuit to realize the positive and negative leakage current test required by the leakage detection module, and ensure the normal operation of the self-checking function of the leakage protection device. For example, the first output side 110 outputs a high level signal, and the second output side 120 outputs a low level signal, or the first output side 110 outputs a low level signal, and the second output side 120 outputs a high level signal.

[0034] By providing different levels of control signals by the control signal generation circuit, the full-bridge circuit can switch different current paths to achieve the expected conduction effect.

[0035] Further, the full-bridge circuit further includes a first branch and a second branch coupled to the leakage detection circuit of the DC switch device. By providing different levels of control signals by the control signal generation circuit, the full-bridge circuit can switch different current paths to achieve the expected conduction effect. At the same time, the first branch is coupled to the first output side, and the second branch is coupled to the second output side. Specifically, when the first output side 110 of the control signal generation circuit outputs a high level and the second output side 120 outputs a low level, the first branch is turned on, and the current flows along the first branch path, thereby generating a positive leakage current; when the first output side 110 is low and the second output side 120 is high, the second branch is turned on, and the current flows along the second branch path, thereby generating a negative leakage current. In this way, the full-bridge circuit can selectively turn on different branches under the condition of different levels of control signals, form a positive and negative bidirectional leakage current path, and meet the requirement of the leakage protection self-checking circuit 100 for testing the direction of leakage current, thereby ensuring the effectiveness and reliability of the leakage protection function.

[0036] In some embodiments, the leakage protection self-checking circuit 100 further comprises a self-checking winding circuit 150. The self-checking winding circuit 150 is coupled to the output side of the full-bridge circuit, for adjusting the size of the total leakage current according to the positive and negative leakage currents generated by the control signal. By adjusting the number of turns of the winding, the self-checking winding circuit 150 can amplify or adjust the leakage current from the full-bridge circuit, so as to form a leakage current suitable for detection, which simulates the real leakage situation. Further, the output side of the full-bridge circuit can be located between the two bridge arms. For example, the self-checking winding circuit 150 can be coupled between the two bridge arms of the full-bridge circuit, for receiving the positive or negative leakage current signal and transmitting the leakage current signal to the subsequent leakage detection circuit. By controlling the conduction path of the full-bridge circuit, the corresponding positive or negative leakage current can be generated in the self-checking winding circuit 150 for leakage protection test. For example, the number of turns of the winding can be 10 turns, which is not limited in the embodiments of the present disclosure.

[0037] Therefore, the leakage protection self-checking circuit 100 not only can generate and detect leakage currents of different directions, but also can periodically self-check the leakage protection function to verify whether the switching device is in a normal protection state, so as to improve the safety and reliability of the switching device.

[0038] In some embodiments, the leakage protection self-checking circuit 100 further comprises a power supply circuit 160 to ensure the normal operation of the leakage protection self-checking circuit 100 and generate the leakage current. The power supply circuit 160 is coupled to the full-bridge circuit to provide the required operating voltage and current for the full-bridge circuit and related components, so as to drive the operation of the leakage protection self-checking circuit 100. Under the action of the power supply circuit 160, the full-bridge circuit can generate positive or negative leakage current according to the control signal for detecting the effectiveness of the leakage protection function.

[0039] Specifically, the positive electrode of the power supply circuit 160 is connected to the source electrode of the first switch 230 and the source electrode of the second switch 240 of the full-bridge circuit, and the source electrode of the third switch 250 and the source electrode of the fourth switch 260 of the full-bridge circuit are grounded. By providing a stable power supply for the full-bridge circuit, it is ensured that the field effect transistors in the full-bridge circuit are turned on or turned off as required by the control signal to accurately generate the leakage current. The power supply circuit 160 can meet the current demand in the self-checking process and ensure the working stability of the entire leakage protection self-checking circuit 100. For example, the power supply circuit 160 can provide a voltage of 5V, and the full-bridge circuit can provide a current of 10mA in positive and negative directions by providing different level control signals by the control signal generation circuit. Of course, the voltage and current are only illustrative and are not intended to limit the protection scope of the present disclosure.

[0040] In some embodiments, the full-bridge circuit is composed of four switching devices, including a first switch 230, a second switch 240, a third switch 250, and a fourth switch 260. Specifically, the sources of the first switch 230 and the second switch 240 are coupled to each other, and the sources of the third switch 250 and the fourth switch 260 are coupled to each other. Meanwhile, the drain of the first switch 230 is coupled to the drain of the third switch 250, and the drain of the second switch 240 is coupled to the drain of the fourth switch 260. Through the above connection relationship, the full-bridge circuit can realize the adjustment of the direction of the leakage current by controlling the conduction and the non-conduction of the four switching devices.

[0041] Further, the plurality of switches in the full-bridge circuit respectively include metal oxide semiconductor field effect transistors (MOSFETs) for controlling the conduction and the non-conduction in the circuit. Of course, the plurality of switches in the full-bridge circuit can also use other types of components other than metal oxide semiconductor field effect transistors to realize the function of the full-bridge circuit in the embodiments of the present disclosure, and therefore, the type of components of the plurality of switches in the embodiments of the present disclosure is not specifically limited. For example, the first switch 230 and the second switch 240 can be P-type metal oxide semiconductor field effect transistors. The sources of the first switch 230 and the second switch 240 are coupled to the power supply voltage end (i.e., the positive electrode of the power supply circuit 160), and the drains are respectively connected to the drains of the third switch 250 and the fourth switch 260 to form the high-side part of the full-bridge circuit. The gates of the first switch 230 and the second switch 240 are connected to the power supply voltage end through the corresponding pull-up resistors (i.e., the second resistor 180 described below), and the conduction state thereof is controlled by the control signal generation circuit through the fifth switch 130 and the sixth switch 140 described below.

[0042] Further, the third switch 250 and the fourth switch 260 can be N-type metal oxide semiconductor field effect transistors, and the gates thereof are driven by the control signal provided by the control signal generation circuit. The sources of the third switch 250 and the fourth switch 260 are respectively grounded, and the drains are respectively coupled to the drains of the first switch 230 and the second switch 240 to form the low-side part of the circuit.

[0043] The full-bridge circuit can realize effective high-low side switching control and ensure the stability and reliability of the full-bridge circuit, while meeting the dynamic performance requirements of the leakage protection self-checking circuit 100.

[0044] In some embodiments, the first branch in the full-bridge circuit includes the first switch 230 and the fourth switch 260. The drain of the first switch 230 is coupled to the drain of the fourth switch 260 through the self-checking winding circuit 150. The first branch is adapted to generate a forward leakage current under the driving of the control signal.

[0045] The second branch includes a second switch 240 and a third switch 250. The drain of the second switch 240 is coupled to the drain of the third switch 250 through the self-check winding circuit 150. The second branch is adapted to generate a negative leakage current under the driving of the control signal.

[0046] Through the alternating action of the first branch and the second branch, the leakage protection self-check circuit 100 can simulate the positive leakage current and the negative leakage current respectively, thereby ensuring the action performance of the leakage protection device to realize the normal work of the leakage protection device under the actual leakage condition.

[0047] Further, the first output side 110 of the control signal generation circuit is connected to the gate of the fourth switch 260 for controlling the on-off state thereof. Specifically, when the control signal generation circuit outputs a high-level signal at the first output side 110, the gate of the fourth switch 260 is driven to be on, so that the first branch forms a path, thereby generating the positive leakage current in the full-bridge circuit. When the control signal generation circuit outputs a low-level signal at the first output side 110, the gate of the fourth switch 260 is in the off state, and the first branch is not on.

[0048] Therefore, the control signal generation circuit can effectively control whether the first branch is on or not to generate the leakage current of a specific direction for detection. This not only enables the leakage protection self-check circuit 100 to work in a high-efficiency state, but also ensures the accurate generation of the positive leakage current, thereby providing a reliable test condition for the subsequent leakage detection.

[0049] Further, the second output side 120 of the control signal generation circuit is connected to the gate of the third switch 250 for controlling the on-off state thereof. When the control signal generation circuit outputs a high-level signal at the second output side 120, the gate of the third switch 250 is driven to be on, so that the second branch forms a path, thereby generating the negative leakage current in the full-bridge circuit. When the control signal generation circuit outputs a low-level signal at the second output side 120, the gate of the third switch 250 is in the off state, and the second branch is not on.

[0050] Therefore, the control signal generation circuit can selectively control the on-off of the second branch to generate the negative leakage current under specific conditions, thereby ensuring that the leakage protection self-check circuit 100 can accurately simulate the negative leakage condition and providing the necessary test current for the leakage detection module, so as to effectively detect the working state of the leakage protection function and improve the safety and reliability of the switching device.

[0051] In some embodiments, the high level and low level control signals output by the control signal generation circuit alternate at a preset time interval to ensure that the first branch and the second branch in the full-bridge circuit are turned on at a specific time, respectively, to generate positive and negative leakage currents. Specifically, the duration of the high level signal and the low level signal is controlled by the preset parameters of the control signal generation circuit, so that the positive and negative leakage currents are alternately generated uniformly and stably. For example, the preset time interval is 100 ms.

[0052] By setting the preset alternating time, the positive and negative leakage conditions in the switching device can be effectively simulated, and it is ensured that the leakage protection self-checking circuit 100 can accurately test the leakage protection function in different directions. The alternating control of the preset time not only provides a multi-directional leakage detection environment, but also improves the real-time and accuracy of the detection, and guarantees the response effect of the system when real leakage occurs.

[0053] In some embodiments, the leakage protection self-checking circuit 100 further comprises a fifth switch 130 and a sixth switch 140 for controlling the gate potential of the first switch 230 and the second switch 240. Specifically, the gate of the fifth switch 130 is coupled to the first output side 110 of the control signal generation circuit, the drain is coupled to the gate of the first switch 230, and the source is grounded. When the first output side 110 outputs a high level control signal, the fifth switch 130 is turned on, thereby pulling the gate of the first switch 230 to the ground potential to ensure that the first switch 230 is in the on state.

[0054] Similarly, the gate of the sixth switch 140 is coupled to the second output side 120 of the control signal generation circuit, the drain is coupled to the gate of the second switch 240, and the source is grounded. When the second output side 120 outputs a high level control signal, the sixth switch 140 is turned on, thereby pulling the gate of the second switch 240 to the ground potential to ensure that the second switch 240 is in the on state.

[0055] In some embodiments, the fifth switch 130 and the sixth switch 140 are both composed of N-type metal oxide semiconductor field effect transistors (MOSFETs) to ensure accurate transmission of the control signal and stable conduction of the circuit. Of course, the fifth switch 130 and the sixth switch 140 in the leakage protection self-checking circuit 100 can also use other types of components to realize the functions of the fifth switch 130 and the sixth switch 140 in the embodiments of the present disclosure, and therefore, the component types of the fifth switch 130 and the sixth switch 140 in the embodiments of the present disclosure are not limited.

[0056] In some embodiments, the leakage protection self-test circuit includes two first resistors 170. These two first resistors 170 are coupled in parallel between the bridge arm consisting of the first switch 230 and the third switch 250 and the self-test winding circuit 150, providing a stable current path. The provision of two first resistors 170 ensures proper current limiting between the drains of the first and third switches 230, 250 in the bridge arm and the self-test winding circuit 150, thereby preventing high current from damaging the full-bridge circuit.

[0057] At the same time, the leakage protection self-test circuit also includes two second resistors 180, one of which is coupled between the positive electrode of the power supply circuit 160 and the gate of the first switch 230, and is used to provide a pull-up function for the gate of the first switch 230; the other second resistor 180 is coupled between the positive electrode of the power supply circuit 160 and the gate of the second switch 240, and is used to provide a similar pull-up function for the gate of the second switch (240). By setting the two second resistors 180, it is possible to ensure that the gates of the first switch 230 and the second switch 240 are maintained at a high level when the control signal is not activated, thereby avoiding mis-conduction.

[0058] like Figure 2 As shown, first, after the switch device receives a test command from the user or control system, the control signal generation circuit of the leakage protection self-test circuit 100 adjusts the current setting to 10mA by controlling the power supply circuit 160, preparing to generate the leakage current required for the test. Subsequently, the control signal generation circuit controls the full-bridge circuit to generate a positive leakage current. This leakage current flows through the self-test winding circuit 150 and the leakage detection circuit to test the leakage protection function. During this process, the leakage detection circuit detects this positive leakage current and determines whether a trip signal is required to trigger the protection action. After the positive leakage current test is completed, the system enters a 100ms waiting phase to ensure the integrity of the positive leakage current detection process.

[0059] Next, the control signal generation circuit controls the full-bridge circuit to generate a negative leakage current in the opposite direction. The control signal generation circuit adjusts the direction of the injected current, generating a negative leakage current that again flows through the self-test winding circuit 150 and the leakage detection circuit. At this point, the leakage detection circuit also detects this negative leakage current and determines whether a trip signal is required to trigger protection. After completing the negative leakage current detection process, the system waits another 100ms to ensure that the negative leakage current detection process is complete.

[0060] After the detection of the positive and negative leakage current is completed, the control signal generation circuit restores the current setting to the initial setting state of the user, realizing the end of the self-checking process. Further, the control signal generation circuit feeds back the test result and the current state to the main control system, so as to confirm the success or failure of the test by the user.

[0061] The process verifies whether the leakage protection function of the leakage protection self-checking circuit 100 is normal through the detection of the positive and negative leakage current, and ensures that the protection action can be triggered effectively when the leakage fault actually occurs.

[0062] The above has described the implementations of the present disclosure, and the above description is exemplary, not exhaustive, and is not limited to the disclosed implementations. Many modifications and changes are obvious to those skilled in the art without departing from the scope and spirit of the described implementations. The selection of the terms used herein is intended to best explain the principles of the implementations, practical applications, or improvements to the technology in the market, or to enable other ordinary skilled persons in the art to understand the various implementations disclosed herein.

Claims

1. A leakage protection self-checking circuit for a direct current switching device, characterized by, Comprising: a control signal generating circuit comprising a first output side (110) and a second output side (120), and adapted to output control electrical signals having high and low levels alternately at the first output side (110) and the second output side (120) respectively; and a full-bridge circuit coupled to the leakage detection circuit of the DC switching device, and comprising: a first branch coupled to the first output side (110) to be turned on in the case that the first output side (110) outputs a high level control electrical signal, to make the full-bridge circuit generate a positive leakage current; and a second branch coupled to the second output side (120) to be turned on in the case that the second output side (120) outputs a high level control electrical signal, to make the full-bridge circuit generate a negative leakage current. The first branch comprises:

2. The ground-fault circuit self-testing circuit of claim 1, wherein, a first switch (230) and a fourth switch (260) both coupled to the first output side (110) and adapted to make the full-bridge circuit generate a positive leakage current, and The second branch comprises: a second switch (240) and a third switch (250) both coupled to the second output side (120) and adapted to make the full-bridge circuit generate a negative leakage current. The gate of the fourth switch (260) is coupled to the first output side (110) of the control signal generating circuit; and 3. The ground-fault circuit self-testing circuit of claim 2, wherein, The gate of the third switch (250) is coupled to the second output side (120) of the control signal generating circuit. The source of the first switch (230) and the source of the second switch (240) are coupled; 4. The ground-fault circuit interrupter self-test circuit of claim 2, wherein, The source of the third switch (250) and the source of the fourth switch (260) are coupled, and The drain of the first switch (230) and the drain of the third switch (250) are coupled, and the drain of the second switch (240) and the drain of the fourth switch (260) are coupled. Further comprising:

5. The ground-fault circuit self-testing circuit of any one of claims 2-4, wherein, a fifth switch (130) whose gate is coupled to the first output side (110) of the control signal generating circuit, whose drain is coupled to the gate of the first switch (230), and whose source is grounded, and adapted to be turned on in the case that the first output side (110) outputs a high level control electrical signal; and a sixth switch (140) whose gate is coupled to the second output side (120) of the control signal generating circuit, whose drain is coupled to the gate of the second switch (240), and whose source is grounded, and adapted to be turned on in the case that the second output side (120) outputs a high level control electrical signal. The first switch (230) and the second switch (240) are P-type metal oxide semiconductor field effect transistors, and 6. The ground-fault circuit self-testing circuit of any one of claims 2-4, wherein, The third switch (250), the fourth switch (260), the fifth switch (130) and the sixth switch (140) comprise N-type metal oxide semiconductor field effect transistors. Further comprising:

7. The ground-fault circuit self-testing circuit of any one of claims 2-4, wherein, ​ A self-check winding circuit (150) coupled to an output side of the full-bridge circuit is adapted to adjust a magnitude of the control electrical signal.

8. The ground fault protection self-test circuit of any of claims 2-4, wherein, Further comprising: A power supply circuit (160) having a positive terminal coupled to a source terminal of the first switch (230) and the second switch (240), and a source terminal of the third switch (250) and a source terminal of the fourth switch (260) grounded, is adapted to supply power to the leakage protection self-check circuit to generate a leakage current.

9. An arc fault protection assembly for a direct current switching device, comprising: Comprising: The leakage protection self-check circuit according to any one of claims 1-8; And A leakage detection circuit coupled to the self-check winding circuit of the leakage protection self-check circuit is adapted to generate a trip signal in a case that the leakage current generated by the leakage protection self-check circuit meets a predetermined condition, or a leakage current generated by a circuit to which the DC switch device is connected meets a predetermined condition.

10. A switching device, characterized by Comprising: The leakage protection assembly according to claim 9; And A trip assembly coupled to the leakage detection circuit of the leakage protection assembly to trip based on the trip signal generated by the leakage detection circuit.

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