Leakage protection device

Abstract

The embodiment of the utility model provides an electric leakage protection device, and relates to the technical field of electric leakage protection. The device comprises a voltage acquisition circuit, a frequency selection circuit and an execution circuit, the voltage acquisition circuit is respectively connected with the converter and the frequency selection circuit, and the execution circuit is respectively connected with the converter and the frequency selection circuit; the frequency selection circuit is used for filtering the voltage signal of the converter acquired by the voltage acquisition circuit so as to reserve a power frequency sub-signal and generate a target voltage signal; the execution circuit is used for controlling the converter to be cut off when the voltage value of the target voltage signal is larger than a preset voltage value. The electric leakage protection device can realize accurate electric leakage fault detection, so that power-off operation is carried out in time, and personal and equipment safety is protected.

Description

Technical Field

[0001] This application relates to the field of leakage current protection technology, and in particular to a leakage current protection device. Background Technology

[0002] A converter is a power electronic device that converts electrical energy from one form to another, commonly used in industrial, energy, and household appliances. However, during the operation of a converter, leakage current can occur due to defects in electrical components or their distributed parameters to ground. This leakage current can not only damage the equipment itself but also threaten the safety of operators; therefore, a residual current device (RCD) is needed for effective monitoring and protection.

[0003] Existing residual current devices (RCDs) typically use a magnetic core surrounding multiple phase conductors at the front end, with several turns of coil wound around the core to detect leakage current. Under normal circumstances, the vector sum of the currents in the multiple phase conductors is zero, there is no leakage current, the magnetic flux generated by the multiple phase conductors in the magnetic core cancels each other out, there is no current in the secondary coil, the sampling resistor cannot sample a voltage, and the subsequent circuit does not operate. When someone touches a phase conductor on the converter side, or the main circuit is grounded, the current in the coil becomes unbalanced, generating leakage current. This induces a current in the secondary coil, the sampling resistor samples a voltage, and the processing circuit disconnects the circuit breaker to protect personnel and equipment safety.

[0004] However, existing residual current devices (RCDs) have low accuracy in detecting leakage current. Utility Model Content

[0005] This application provides a leakage current protection device to solve the problem of low accuracy in leakage current detection of existing leakage current protection devices.

[0006] In a first aspect, embodiments of this application provide a leakage current protection device, comprising:

[0007] Voltage acquisition circuit, frequency selection circuit, and execution circuit;

[0008] The voltage acquisition circuit is connected to the converter and the frequency selection circuit respectively, and the execution circuit is connected to the converter and the frequency selection circuit respectively.

[0009] The frequency selection circuit is used to filter the voltage signal of the converter acquired by the voltage acquisition circuit to retain the power frequency sub-signal and generate the target voltage signal.

[0010] The execution circuit is used to control the converter to cut off when the voltage value of the target voltage signal is greater than a preset voltage value.

[0011] In one possible implementation, the frequency selection circuit is specifically used to filter the high-frequency sub-signals and low-frequency sub-signals of the voltage signal to generate the target voltage signal.

[0012] In one possible implementation, the voltage acquisition circuit includes:

[0013] The secondary coil and the sampling resistor connected to the secondary coil;

[0014] The secondary coil is wound around the power supply line of the converter and is used to collect the leakage current of the converter.

[0015] The sampling resistor is used to convert the leakage current into a voltage signal.

[0016] In one possible implementation, the execution circuit includes:

[0017] Latch circuit and trip unit;

[0018] The latch sub-circuit is connected to the frequency selection circuit and the trip unit respectively, and the trip unit is also connected to the converter;

[0019] The latching sub-circuit is used to send a cut-off signal to the trip unit when the voltage value of the target voltage signal is greater than the preset voltage value;

[0020] The trip unit is used to control the converter to shut down according to the cut-off signal.

[0021] In one possible implementation, the device further includes:

[0022] A voltage follower circuit, wherein the voltage follower circuit is connected to the sampling resistor and the frequency selection circuit respectively;

[0023] The voltage follower circuit is used to process the voltage signal to generate an amplified voltage signal.

[0024] In one possible implementation, the device further includes:

[0025] A signal processing sub-circuit, which is connected to the frequency selection circuit and the latch sub-circuit respectively;

[0026] The signal processing sub-circuit is used to amplify the target voltage signal to generate an amplified target voltage signal.

[0027] In one possible implementation, the device further includes:

[0028] An alarm module is connected to the latch sub-circuit.

[0029] The latch sub-circuit is also used to send an alarm signal to the alarm module when the voltage value of the target voltage signal is greater than the preset voltage value;

[0030] The alarm module is used to output alarm information based on the alarm signal.

[0031] In one possible implementation, the device further includes:

[0032] A timing module, which is connected to the execution circuit;

[0033] The execution circuit is used to control the timing module to start timing when the voltage value of the target voltage signal is greater than the preset voltage value, and to control the timing module to stop timing and reset when the voltage value of the target voltage signal is less than or equal to the preset voltage value.

[0034] The timing module is used to send a timing completion command to the execution circuit when the cumulative time obtained by timing reaches the preset time.

[0035] The execution circuit is also used to control the inverter to cut off according to the timing completion command.

[0036] In one possible implementation, the latch sub-circuit is further configured to latch the voltage value of the target voltage signal.

[0037] In one possible implementation, the device further includes:

[0038] A configuration parameter acquisition module is connected to the timing module and the execution circuit respectively. It is used to acquire the preset duration and the preset voltage value set by the user, and configure the timing module according to the preset duration and the execution circuit according to the preset voltage value.

[0039] The leakage current protection device provided in this application includes a voltage acquisition circuit, a frequency selection circuit, and an execution circuit. The voltage acquisition circuit is connected to both the converter and the frequency selection circuit, so that the voltage acquisition circuit acquires the corresponding leakage current in the transformer, converts it into a voltage signal, processes it through voltage tracking, and then sends it to the frequency selection circuit for filtering, retaining the power frequency sub-signal and generating a target voltage signal. This effectively distinguishes between the power frequency leakage current signal (power frequency sub-signal) and interference signals, ensuring that the leakage current protection device accurately detects actual leakage current faults. The execution circuit is connected to both the converter and the frequency selection circuit, so that when the voltage value of the target voltage signal obtained after filtering by the frequency selection circuit is greater than a preset voltage value, the converter is controlled to cut off the power supply, thereby eliminating the potential danger caused by leakage current faults in a timely manner and reducing the risk to equipment and personal safety.

[0040] In addition to the technical problems solved by the embodiments of this application, the technical features constituting the technical solutions, and the beneficial effects brought about by the technical features of these technical solutions as described above, other technical problems that can be solved by the device provided by the embodiments of this application, other technical features included in the technical solutions, and the beneficial effects brought about by these technical features will be further described in detail in the specific implementation. Attached Figure Description

[0041] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0042] Figure 1 This is a schematic diagram of the leakage current protection device provided in the embodiments of this application.

[0043] Explanation of reference numerals in the attached figures:

[0044] 10-Voltage acquisition circuit; 101-Secondary coil; 102-Sampling resistor; 103-Converter

[0045] 201 - Frequency selection circuit; 202 - Voltage follower circuit; 203 - Signal processing sub-circuit;

[0046] 30 - Execution circuit; 301 - Latch sub-circuit; 302 - Trip unit.

[0047] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0048] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0049] A converter is a power electronic device that converts electrical energy from one form to another, and is commonly used in industrial, energy, and household appliances. However, during the operation of a converter, due to defects in electrical components or their distributed parameters to ground, leakage current may occur. This leakage current can not only damage the equipment itself but also threaten the safety of operators. Therefore, a residual current device (RCD) is needed for effective monitoring and protection.

[0050] Existing residual current devices (RCDs) typically employ a structure where a magnetic core surrounds multiple phase wires to detect leakage current in the circuit. Specifically, the magnetic core at the front end of the RCD "wraps" several wires (phase wires). When current flows normally, it travels up one wire and returns from another, effectively forming a closed loop. The vector sum of the currents in the multiple phase wires is zero, meaning the current inflow and outflow of all phase wires are completely balanced. At this point, the magnetic flux generated by the multiple phase wires in the magnetic core cancels each other out, no induced current is generated in the secondary coil, the sampling resistor cannot detect a voltage signal, and the subsequent processing circuit remains inactive.

[0051] When a leakage current occurs, such as when someone touches a phase wire or the main circuit is grounded, the current balance is disrupted, resulting in an imbalance in the current within the coil. This imbalance creates an asymmetrical magnetic flux in the magnetic core, inducing a current signal in the secondary coil. The sampling resistor captures this induced current and converts it into a voltage signal, which is then transmitted to the subsequent processing circuitry. The processing circuitry analyzes and judges this signal. When it detects that the leakage current exceeds a set safety threshold, it quickly activates the circuit breaker to disconnect the power supply, protecting personnel safety and preventing further damage to equipment due to the leakage.

[0052] However, due to the significant high-frequency common-mode interference and DC components generated during converter operation, these interference signals can be superimposed on the leakage current signal, making it difficult for conventional residual current devices (RCDs) to correctly distinguish between normal operation and leakage faults. Specifically, the superposition of high-frequency common-mode interference signals on the leakage current signal causes the RCD to misinterpret it as a leakage fault, triggering protection and leading to abnormal power outages. Furthermore, the presence of the DC component prevents the RCD from accurately detecting the actual leakage current signal, resulting in the failure to trigger protection when a leakage fault occurs, posing a safety hazard. Increasing the protection threshold of the RCD can easily cause it to fail to operate at the rated safe current, also leading to safety accidents.

[0053] Based on this, the technical concept of this application is as follows: Conventional leakage current protection devices suffer from the superposition of numerous interference signals (high-frequency common-mode interference signals and DC component interference signals) in the leakage current signal, making it impossible for the device to accurately determine the existence of a leakage fault. Therefore, if these interference signals can be filtered out, retaining the actual leakage current signal (power frequency sub-signal), the leakage current protection device can achieve accurate detection of leakage faults. Thus, after the voltage acquisition circuit acquires the voltage signal of the converter leakage current, a frequency selection circuit is used to filter the voltage signal, retaining the power frequency sub-signal and generating a target voltage signal. Finally, when the voltage value of the target voltage signal exceeds a preset voltage value, a timely response is made to disconnect the converter to protect personal safety. This method effectively solves the problem of low leakage detection accuracy caused by excessive interference signals in conventional leakage current protection devices, improving the accuracy and reliability of leakage current detection of the converter.

[0054] To make the above-mentioned objectives, features, and advantages of the embodiments of this application more apparent and understandable, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0055] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0056] It should be noted that the functions and structures of the various circuits, modules, and circuit elements in the leakage current protection device provided in this application are all functions and structures found in commonly available devices on the market, and belong to the prior art. For example, the existing latch circuit (latch sub-circuit) already has the capability to receive the target voltage signal output by the signal processing sub-circuit, then compare this signal with a pre-stored reference voltage, and when the voltage value of the target voltage signal is greater than the preset reference voltage value, the latch circuit will latch the circuit and trigger the output cut-off signal. The remaining circuits, modules, and circuit elements will not be described in detail here.

[0057] Figure 1 This is a schematic diagram of the leakage current protection device provided in an embodiment of this application. Please refer to... Figure 1A leakage current protection device includes a voltage acquisition circuit 10, a frequency selection circuit 201, and an execution circuit 30. The voltage acquisition circuit 10 is connected to both a converter 103 and the frequency selection circuit 201 to acquire the leakage current in the converter 103 and convert it into a voltage signal, which is then sent to the frequency selection circuit 201. The frequency selection circuit 201 filters the voltage signal acquired by the voltage acquisition circuit 10 from the converter 103 to retain the power frequency sub-signal and generate a target voltage signal. Meanwhile, the execution circuit 30 is connected to both the converter 103 and the frequency selection circuit 201. The execution circuit 30 acquires the corresponding target voltage signal through its connection with the frequency selection circuit 201, and controls the converter 103 to cut off when the voltage value of the target voltage signal is greater than a preset voltage value.

[0058] Among them, the power frequency sub-signal refers to the 50 Hz or 60 Hz power grid frequency signal, which is an important component of the normal leakage current in the power system.

[0059] Specifically, the frequency selection circuit 201 is used to filter the high-frequency sub-signals and low-frequency sub-signals of the voltage signal to generate the target voltage signal.

[0060] It should be noted that the frequency selection circuit 201 can use a frequency selection filter to filter the voltage signal. By setting two cutoff frequencies (low cutoff frequency and high cutoff frequency) to the frequency selection filter, the high-frequency sub-signals and low-frequency sub-signals of the voltage signal can be intercepted and filtered, so that the power frequency sub-signal can pass smoothly and generate the target voltage signal. In practical applications, different filters can be selected to filter the voltage signal according to the working conditions of the converter 103, such as resistor-capacitor filters and inductor-capacitor filters. This application embodiment does not impose specific limitations here.

[0061] It should be understood that when the switching devices of converter 103 switch at high speed, high-frequency voltage pulses are generated, which form high-frequency common-mode interference through parasitic capacitance or line coupling. The unbalanced operating state or fault of the converter will also introduce DC components, causing deviations in AC leakage current detection. These interference signals formed by high-frequency common-mode interference and DC components will be superimposed on the leakage current of the current device. Therefore, in order to remove these interference signals from the leakage current detection accuracy of the leakage protection device, frequency selection circuit 201 is used to filter the high-frequency sub-signals (high-frequency common-mode interference) and low-frequency sub-signals (DC components) of the voltage signal, retain the power frequency sub-signal, and generate the target voltage signal.

[0062] Understandably, through the coordinated operation of the voltage acquisition circuit 10, the frequency selection circuit 201, and the execution circuit 30, this leakage current protection device can effectively retain the power frequency sub-signal among various interference signals of the leakage current, thereby generating the target voltage signal. This enables accurate detection of the leakage current of the converter 103 and timely response, controlling the converter 103 to cut off, protecting equipment and personal safety, and significantly improving the accuracy and reliability of leakage current protection.

[0063] In one implementation, the voltage acquisition circuit 10 includes a secondary coil 101 and a sampling resistor 102 connected to the secondary coil; the secondary coil 101 is wound around the power supply line of the converter 103 for acquiring the leakage current of the converter 103, while the sampling resistor 102 is used to convert the leakage current into a voltage signal.

[0064] It should be noted that the secondary coil 101 is wound around the power supply line of the converter 103. It uses the principle of electromagnetic induction to detect the leakage current and outputs the leakage current to the sampling resistor 102. The sampling resistor 102 converts the current signal into a voltage signal through Ohm's law.

[0065] Accordingly, the execution circuit 30 includes a latch sub-circuit 301 and a trip unit 302; the latch sub-circuit 301 is connected to the frequency selection circuit 201 and the trip unit 302 respectively, and the trip unit 302 is also connected to the converter 103.

[0066] The latching sub-circuit 301 is used to send a cut-off signal to the trip unit 302 when the voltage value of the target voltage signal is greater than the preset voltage value, and to latch the voltage value of the target voltage signal; the trip unit 302 is used to control the converter 103 to cut off according to the cut-off signal.

[0067] It should be understood that when the selected frequency circuit 201 filters the interference signal through the filter and retains the power frequency sub-signal to generate the target voltage signal, the target voltage signal is transmitted to the latching sub-circuit 301. The latching sub-circuit 301 compares the voltage value of the target voltage signal with the preset voltage value stored in it. If the voltage value of the target voltage signal is greater than the preset voltage value, it sends a cut-off signal to the trip unit 302 and latches the voltage value of the target voltage signal. When the trip unit 302 receives the cut-off signal, it triggers the circuit protection action and controls the converter 103 to cut off. After the leakage fault is repaired, the trip unit can be manually closed or automatically reset using an automatically resettable trip unit to restore the normal operation of the leakage protection device.

[0068] Optionally, to better protect personnel and electrical equipment, the leakage current protection device also includes an alarm module connected to the latching sub-circuit 301. When the latching sub-circuit 301 compares its stored preset voltage value with the target voltage signal value, and determines that the target voltage signal value is greater than the preset voltage value, it sends a cut-off signal to the trip unit 302 and an alarm signal to the alarm module simultaneously. The alarm module then outputs alarm information based on the alarm signal to indicate that there is a leakage current in the current device and to remind relevant maintenance personnel to perform timely repairs.

[0069] It should be noted that the alarm module can display alarm information on the screen, control the corresponding fault warning light to flash, and also play preset music corresponding to the alarm information to provide reminders.

[0070] Optionally, to prevent the trip unit from being repeatedly triggered by transiently fluctuating signals, the leakage current protection device also includes a timing module connected to the execution circuit. When the voltage value of the target voltage signal is greater than the preset voltage value, the latching sub-circuit 301 sends a cut-off signal to the execution circuit 30. The execution circuit 30 then controls the timing module to start timing, and when the voltage value of the target voltage signal is less than or equal to the preset voltage value, it controls the timing module to stop timing and reset. Furthermore, the timing module is used to send a timing completion command to the execution circuit 30 when the accumulated time reaches the preset time. Then, the execution circuit 30 controls the converter to cut off according to the timing completion command sent by the timing module.

[0071] Understandably, by utilizing a timing module, false triggering of the trip unit 302 due to instantaneous fluctuations or short-term interference signals can be avoided. Power-off protection is only triggered when the target voltage signal continuously exceeds the preset voltage value for a preset duration. This method effectively reduces false tripping of the trip unit 302 and improves the stability and reliability of the leakage current protection device.

[0072] It should be noted that in actual use, the preset duration of the timing module can be independently configured and adjusted according to the needs of different occasions. The specific configuration process can be operated through the configuration parameter acquisition module in the leakage protection device. The configuration parameter acquisition module is connected to the timing module and the execution circuit respectively. It is used to acquire the preset duration and preset voltage value set by the user, and configure the timing module according to the preset duration and configure the execution circuit according to the preset voltage value.

[0073] For example, some industrial equipment typically requires high sensitivity, so a shorter duration and lower voltage can be set to ensure that the leakage current protection device responds quickly to leakage faults. For household electrical appliances, to avoid false triggering due to short-term fluctuations, a longer duration and moderate voltage can be set to improve the stability of the leakage current protection device.

[0074] Understandably, this method allows users to flexibly configure preset duration and preset voltage values ​​according to different scenario requirements, greatly improving user convenience and experience. Furthermore, the clear division of labor between the parameter acquisition module, timing module, and execution circuit facilitates subsequent equipment maintenance and functional expansion.

[0075] In one possible implementation, to stably transmit the voltage signal of the leakage current to the frequency selection circuit 201, and to accurately input the target transformer signal retained after filtering by the frequency selection circuit 201 to the execution circuit 30 for judgment, the device further includes: a voltage follower circuit 202 and a signal processing sub-circuit 203; the voltage follower circuit 202 is connected to the sampling resistor 102 and the frequency selection circuit 201 respectively; the signal processing sub-circuit 203 is connected to the frequency selection circuit 201 and the latching sub-circuit 301 respectively.

[0076] Among them, the voltage follower circuit 202 is used to amplify the voltage signal to generate an amplified voltage signal; the signal processing sub-circuit 203 is used to amplify the target voltage signal to generate an amplified target voltage signal.

[0077] It should be noted that the target voltage signal can be the target voltage signal generated by the frequency selection circuit 201, or the target voltage signal after being amplified by the signal processing sub-circuit 203; correspondingly, the voltage signal can be the voltage signal generated by the voltage acquisition circuit 10, or the amplified voltage signal generated after being amplified by the voltage follower circuit 202.

[0078] It should be understood that by using the voltage follower circuit 202 to initially amplify the sampled voltage signal to generate an amplified voltage signal, the voltage signal input to the frequency selection circuit 201 can be ensured to be more stable, avoiding inaccurate frequency selection due to a weak signal. After the frequency selection circuit 201 generates the target voltage signal, the signal processing sub-circuit 203 further amplifies the target voltage signal to generate an amplified target voltage signal. This further ensures that the signal can be accurately identified by the latching sub-circuit 301, thereby improving the reliability of the latching sub-circuit 301's judgment and achieving precise circuit protection.

[0079] Understandably, through the multi-stage amplification and processing of the voltage follower circuit 202 and the signal processing sub-circuit 203, the amplitude of the target voltage signal can be made clearer and easier to compare with the preset voltage value, avoiding false triggering and leakage triggering of the leakage protection device, improving the action accuracy of the execution circuit 30, ensuring that the power supply is quickly cut off when leakage actually occurs, and protecting personal and equipment safety.

[0080] The leakage current protection device provided in this application includes a voltage acquisition circuit, a frequency selection circuit, and an execution circuit. The voltage acquisition circuit is connected to both the converter and the frequency selection circuit, so that the voltage acquisition circuit acquires the corresponding leakage current in the transformer, converts it into a voltage signal, processes it through voltage tracking, and then sends it to the frequency selection circuit for filtering, retaining the power frequency sub-signal and generating a target voltage signal. This effectively distinguishes between the power frequency leakage current signal (power frequency sub-signal) and interference signals, ensuring that the leakage current protection device accurately detects actual leakage current faults. The execution circuit is connected to both the converter and the frequency selection circuit, so that when the voltage value of the target voltage signal obtained after filtering by the frequency selection circuit is greater than a preset voltage value, the converter is controlled to cut off the power supply, thereby eliminating the potential danger caused by leakage current faults in a timely manner and reducing the risk to equipment and personal safety.

[0081] It should be noted that the devices in the embodiments provided in this application are all common devices on the market. They can be selected according to the needs when used. The circuit connection relationship of each device is a simple series and parallel connection circuit, which can be easily implemented by those skilled in the art. It belongs to the prior art and will not be described in detail here.

[0082] The various embodiments or implementation methods described in this specification are presented in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other.

[0083] It should be noted that the terms "one embodiment," "embodiment," "exemplary embodiment," "some embodiments," etc., mentioned in the specification indicate that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments, whether explicitly described or not, is within the knowledge scope of those skilled in the art.

[0084] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A leakage current protection device, characterized in that, include: Voltage acquisition circuit, frequency selection circuit, and execution circuit; The voltage acquisition circuit is connected to the converter and the frequency selection circuit respectively, and the execution circuit is connected to the converter and the frequency selection circuit respectively. The frequency selection circuit is used to filter the voltage signal of the converter acquired by the voltage acquisition circuit to retain the power frequency sub-signal and generate the target voltage signal. The execution circuit is used to control the converter to cut off when the voltage value of the target voltage signal is greater than a preset voltage value.

2. The leakage current protection device according to claim 1, characterized in that, The frequency selection circuit is specifically used to filter the high-frequency sub-signals and low-frequency sub-signals of the voltage signal to generate the target voltage signal.

3. The leakage current protection device according to claim 1 or 2, characterized in that, The voltage acquisition circuit includes: The secondary coil and the sampling resistor connected to the secondary coil; The secondary coil is wound around the power supply line of the converter and is used to collect the leakage current of the converter. The sampling resistor is used to convert the leakage current into a voltage signal.

4. The leakage current protection device according to claim 1 or 2, characterized in that, The execution circuit includes: Latch circuit and trip unit; The latch sub-circuit is connected to the frequency selection circuit and the trip unit respectively, and the trip unit is also connected to the converter; The latching sub-circuit is used to send a cut-off signal to the trip unit when the voltage value of the target voltage signal is greater than the preset voltage value; The trip unit is used to control the converter to shut down according to the cut-off signal.

5. The leakage current protection device according to claim 3, characterized in that, The device further includes: A voltage follower circuit, wherein the voltage follower circuit is connected to the sampling resistor and the frequency selection circuit respectively; The voltage follower circuit is used to amplify the voltage signal to generate an amplified voltage signal.

6. The leakage current protection device according to claim 4, characterized in that, The device further includes: A signal processing sub-circuit, which is connected to the frequency selection circuit and the latch sub-circuit respectively; The signal processing sub-circuit is used to amplify the target voltage signal to generate an amplified target voltage signal.

7. The leakage current protection device according to claim 4, characterized in that, The device further includes: An alarm module is connected to the latch sub-circuit. The latch sub-circuit is also used to send an alarm signal to the alarm module when the voltage value of the target voltage signal is greater than the preset voltage value; The alarm module is used to output alarm information based on the alarm signal.

8. The leakage current protection device according to claim 1 or 2, characterized in that, The device further includes: A timing module, which is connected to the execution circuit; The execution circuit is used to control the timing module to start timing when the voltage value of the target voltage signal is greater than the preset voltage value, and to control the timing module to stop timing and reset when the voltage value of the target voltage signal is less than or equal to the preset voltage value. The timing module is used to send a timing completion command to the execution circuit when the cumulative time obtained by timing reaches the preset time. The execution circuit is also used to control the inverter to cut off according to the timing completion command.

9. The leakage current protection device according to claim 4, characterized in that, The latch sub-circuit is also used to latch the voltage value of the target voltage signal.

10. The leakage current protection device according to claim 8, characterized in that, The device further includes: A configuration parameter acquisition module is connected to the timing module and the execution circuit respectively. It is used to acquire the preset duration and the preset voltage value set by the user, and configure the timing module according to the preset duration and the execution circuit according to the preset voltage value.

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