Leakage detection circuit, method thereof, electrical equipment and vehicle

Abstract

The present invention discloses a leakage detection circuit and its method, an electrical equipment and a vehicle. The leakage detection circuit includes: a magnetic conductor, a PWM driving module, a reference voltage module, a modulation module and a control module. Among them, the magnetic conductor is wound with a coil; one end of the PWM driving module is connected to the coil and is used to output a PWM driving signal to the coil to excite the magnetic conductor, so that the magnetic conductor outputs a corresponding induced voltage signal through the coil; the reference voltage module is used to provide a reference voltage; the modulation module is used to generate a fluxgate modulation basic waveform based on the PWM driving signal, the induced voltage signal and the reference voltage; the control module is used to perform leakage detection on the electrical equipment based on the offset condition and / or fluctuation condition of the fluxgate modulation basic waveform relative to the reference voltage. The present invention improves the accuracy of leakage detection, and the leakage detection circuit is simpler, while maintaining high stability, effectively enhancing the reliability of leakage detection.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicles, and in particular, to a leakage detection circuit and method, an electrical device, and a vehicle. Background Art

[0002] With the rapid development of electric vehicles, the safety standards for charging equipment have become increasingly strict. Especially for residual leakage current protection, it is required that charging facilities must be equipped with efficient leakage protection devices to ensure user safety.

[0003] In related technologies, to meet the safety requirements of charging equipment, leakage detection is usually based on a photovoltaic inverter. Specifically, different level signals are output by a comparator to control the conduction states of multiple transistors, and then the DC sources corresponding to the multiple transistors are switched, so that the leakage detection winding switches between charging states in opposite current directions, realizing the detection of the direction of the leakage current. When the leakage current detection winding reaches the charging saturation state, the level signal output by the comparator is inverted and a carrier signal is generated. The filter circuit filters the voltage across the leakage current sampling resistor based on this carrier signal, and finally obtains a leakage voltage signal.

[0004] However, in the leakage detection device based on a photovoltaic inverter, the use of components such as multiple transistors and multiple DC sources not only makes the circuit design complex, but also increases the difficulty of leakage processing. This complexity leads to a reduction in the reliability and response speed of leakage detection, affecting the overall stability of the leakage detection device. Summary of the Invention

[0005] The present invention aims to at least solve one of the technical problems existing in the prior art.

[0006] For this reason, an object of the present invention is to provide a leakage detection circuit, which improves the accuracy of leakage detection and enhances the safety performance of the entire leakage detection circuit. In addition, since the leakage detection circuit uses a reference voltage as a direct reference, the complex calculation and processing processes are reduced, making the design of the leakage detection circuit simpler and easier to implement, while maintaining high stability, thereby effectively improving the reliability and response speed of leakage detection.

[0007] For this reason, a second object of the present invention is to provide a leakage detection method.

[0008] For this reason, a third object of the present invention is to provide an electrical device.

[0009] For this reason, a fourth object of the present invention is to provide a vehicle.

[0010] To achieve the above object, an embodiment of the first aspect of the present invention discloses a leakage detection circuit for an electrical device. The leakage detection circuit includes: a magnetic conductor having a through hole axially penetrating therethrough, a power supply connection line passing through the through hole, one end of the power supply connection line being connected to a first power supply, and the other end being connected to the electrical device, and a coil wound around the magnetic conductor; a PWM (Pulse Width Modulation) driving module, one end of the PWM driving module being connected to the coil, configured to output a PWM driving signal to the coil to excite the magnetic conductor, so that the magnetic conductor outputs a corresponding induced voltage signal through the coil; a reference voltage module for providing a reference voltage; a modulation module respectively connected to the PWM driving module, the reference voltage module, and the coil, configured to generate a fluxgate modulation basic waveform based on the PWM driving signal, the induced voltage signal, and the reference voltage; and a control module respectively connected to the modulation module and the reference voltage module, configured to perform leakage detection on the electrical device based on the offset and / or fluctuation of the fluxgate modulation basic waveform with respect to the reference voltage.

[0011] According to the leakage detection circuit of the embodiment of the present invention, the PWM driving module is connected to the coil, and can provide a PWM driving signal to the coil to excite the magnetic conductor, so that the magnetic conductor outputs a corresponding induced voltage signal through the coil. The PWM driving signal is also connected to the modulation module and can transmit the PWM driving signal to the modulation module. At the same time, the modulation module is also respectively connected to the reference voltage module and the coil to receive the reference voltage provided by the reference voltage module and the induced voltage signal output by the coil. In this way, the modulation module can generate a fluxgate modulation basic waveform based on the received PWM driving signal, induced voltage signal, and reference voltage, and then transmit the fluxgate modulation basic waveform to the control module, enabling the control module to perform leakage detection on the electrical device according to the offset and / or fluctuation of the fluxgate modulation basic waveform with respect to the reference voltage. This not only improves the accuracy of leakage detection but also enhances the safety performance of the entire leakage detection circuit. In addition, since the leakage detection circuit uses the reference voltage as a direct reference, it reduces the complex calculation and processing process, makes the design of the leakage detection circuit simpler and easier to implement, while maintaining high stability, thereby effectively improving the reliability and response speed of leakage detection.

[0012] In addition, according to the leakage detection circuit of the above embodiment of the present invention, the following additional technical features may also be provided:

[0013] In some embodiments, the control module is configured to perform leakage detection on the electrical device based on the offset and / or fluctuation of the fluxgate modulation basic waveform relative to the reference voltage, including: when the fluxgate modulation basic waveform has an offset relative to the reference voltage and / or the fluxgate modulation basic waveform fluctuates relative to the reference voltage, it is determined that the electrical device has a leakage. Thereby, the accuracy and reliability of leakage detection are improved, and the detection process is simplified by directly monitoring the relationship between the fluxgate modulation basic waveform and the reference voltage, making the circuit design simpler and easier to implement, while ensuring a high degree of stability, and further effectively enhancing the safety performance of the entire leakage detection, and being able to detect and respond to potential leakage risks in a timely manner.

[0014] In some embodiments, after the control module determines that the electrical device has a leakage, it includes: determining the leakage type of the electrical device according to the offset and / or fluctuation of the fluxgate modulation basic waveform relative to the reference voltage. Thereby, it provides a basis for taking targeted maintenance measures based on the leakage type, and at the same time improves the response accuracy and processing efficiency of leakage detection, helps to quickly locate the root cause of the problem, and enhances the safety and reliability of the overall leakage detection circuit.

[0015] In some embodiments, the control module determines the leakage type of the electrical device according to the offset and / or fluctuation of the fluxgate modulation basic waveform relative to the reference voltage, including: when the fluxgate modulation basic waveform has an overall offset in the same longitudinal direction relative to the reference voltage, it is determined that the electrical device has a DC leakage. Thereby, it provides accurate information for fault diagnosis, facilitates taking targeted measures for repair, and effectively improves the safety and reliability of leakage detection.

[0016] In some embodiments, the control module determines the leakage type of the electrical device according to the offset and / or fluctuation of the fluxgate modulation basic waveform relative to the reference voltage, including: when the fluxgate modulation basic waveform fluctuates periodically relative to the reference voltage, it is determined that the electrical device has an AC leakage. Thereby, it provides accurate information for fault diagnosis, facilitates taking targeted measures for repair, and effectively improves the safety and reliability of leakage detection.

[0017] In some embodiments, the control module determines the leakage type of the electrical device according to the offset and / or fluctuation of the fluxgate modulation basic waveform relative to the reference voltage, including: when the fluxgate modulation basic waveform fluctuates periodically relative to the reference voltage and there is an overall offset in the same longitudinal direction, it is determined that the electrical device has AC-DC superimposed leakage. Thereby, precise information is provided for fault diagnosis, facilitating the adoption of targeted measures for repair, and effectively improving the safety and reliability of leakage detection.

[0018] In some embodiments, the leakage detection circuit further includes: an amplification module, the input end of the amplification module is respectively connected to the modulation module and the reference voltage module, and the output end of the amplification module is connected to the control module, and is used to amplify the fluxgate modulation basic waveform and the reference voltage. Thereby, not only the sensitivity of leakage detection is improved, but also the accuracy and reliability of processing the fluxgate modulation basic waveform are ensured, enabling the control module to more clearly identify and process the offset and / or fluctuation of the fluxgate modulation basic waveform based on the amplified reference voltage, thus ensuring the efficient operation and safety of the leakage detection circuit, not only improving the leakage detection accuracy, but also further enhancing the reliability and response speed of the leakage detection circuit.

[0019] In some embodiments, the reference voltage module includes: a first resistor, one end of the first resistor is connected to the second power supply; a second resistor, one end of the second resistor is connected to the other end of the first resistor, and the other end of the second resistor is grounded; a first operational amplifier, the non-inverting input end of the first operational amplifier is respectively connected to the other end of the first resistor and one end of the second resistor, the inverting input end of the first operational amplifier is connected to the output end of the first operational amplifier, and the output end of the first operational amplifier is respectively connected to the modulation module and the amplification module, and is used to output the reference voltage to the modulation module and the amplification module. Thereby, the accuracy and reliability of the entire leakage detection circuit are improved.

[0020] In some embodiments, the modulation module includes: a switch unit, the first end of the switch unit is connected to one end of the coil, the second end of the switch unit is connected to the PWM drive module, and the second end of the switch unit is also grounded; an operational amplifier unit, the non-inverting input end of the operational amplifier unit is respectively connected to the third end of the switch unit and the output end of the first operational amplifier, the inverting input end of the operational amplifier unit is respectively connected to the second power supply and one end of the coil, the inverting input end of the operational amplifier unit is also grounded, and the output end of the operational amplifier unit is respectively connected to the amplification module and one end of the coil. Thereby, it is convenient for the control module to perform leakage analysis and leakage detection based on the amplified fluxgate modulation basic waveform, thus improving the sensitivity and accuracy of leakage detection.

[0021] In some embodiments, the switching unit includes: a MOS transistor, a third resistor, and a fourth resistor; one end of the third resistor is connected to one end of the coil, and the other end of the third resistor is connected to the gate of the MOS transistor and the PWM driving module; the drain of the MOS transistor is connected to the PWM driving module through the fourth resistor, the drain of the MOS transistor is also grounded, and the source of the MOS transistor is connected to the non-inverting input terminal of the operational amplifier unit. Thereby, not only the safety and stability of the entire leakage detection circuit are ensured, but also a reliable path is provided for the transmission of the PWM driving signal.

[0022] In some embodiments, the operational amplifier unit includes: a second operational amplifier, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, and a ninth resistor; the non-inverting input terminal of the second operational amplifier is connected to the output terminal of the first operational amplifier through the fifth resistor; the non-inverting input terminal of the second operational amplifier is also connected to the source of the MOS transistor through the sixth resistor; the inverting input terminal of the second operational amplifier is connected to the second power supply through the seventh resistor, the inverting input terminal of the second operational amplifier is grounded through the eighth resistor, and the inverting input terminal of the second operational amplifier is also connected to one end of the coil through the ninth resistor; the output terminal of the second operational amplifier is respectively connected to one end of the coil and the amplification module. Thereby, the fluxgate modulation basic waveform processed by the second operational amplifier is transmitted to the amplification module through its output terminal, so as to further amplify the fluxgate modulation basic waveform and ensure high sensitivity and reliability in the subsequent leakage detection process.

[0023] In some embodiments, the modulation module further includes: a capacitor, one end of the capacitor is connected to one end of the ninth resistor, and the other end of the capacitor is connected to the other end of the ninth resistor. Thereby, it is ensured that the induced voltage signal transmitted to the second operational amplifier is more pure and stable, which further helps to improve the quality of the fluxgate modulation basic waveform, makes the subsequent leakage detection more accurate and reliable, and at the same time enhances the anti-interference ability of the entire leakage detection circuit.

[0024] In some embodiments, the amplification module includes: a third operational amplifier, a tenth resistor, an eleventh resistor, and a resistor unit; the non-inverting input terminal of the third operational amplifier is respectively connected to the output terminal of the second operational amplifier, the output terminal of the first operational amplifier, and the other end of the coil through the resistor unit; the inverting input terminal of the third operational amplifier is connected to the output terminal of the first operational amplifier through the tenth resistor, the inverting input terminal of the third operational amplifier is further connected to one end of the eleventh resistor, and the output terminal of the third operational amplifier is connected to the control module; the other end of the eleventh resistor is connected to the control module. Thereby, the third operational amplifier can effectively amplify the fluxgate modulation basic waveform and the reference voltage, ensuring that even tiny offset conditions and / or fluctuation conditions can be accurately acquired, improving the sensitivity and accuracy of leakage detection, and enhancing the reliability and stability of the entire leakage detection circuit.

[0025] In some embodiments, the resistor unit includes: a twelfth resistor, a thirteenth resistor, a fourteenth resistor, and a fifteenth resistor; one end of the twelfth resistor is respectively connected to the output terminal of the second operational amplifier and one end of the coil, and the other end of the twelfth resistor is respectively connected to one end of the thirteenth resistor and the output terminal of the first operational amplifier; the other end of the thirteenth resistor is connected to one end of the fourteenth resistor; the other end of the fourteenth resistor is respectively connected to the other end of the coil and one end of the fifteenth resistor; the other end of the fifteenth resistor is connected to the non-inverting input terminal of the third operational amplifier. Thereby, the transmission of the fluxgate modulation basic waveform and the reference voltage is realized, and it is ensured that the fluxgate modulation basic waveform and the reference voltage are properly voltage-divided and filtered before entering the third operational amplifier, thereby improving the quality and stability of the fluxgate modulation basic waveform and the reference voltage, and further enhancing the reliability and accuracy of the entire leakage detection circuit.

[0026] In some embodiments, the modulation module is specifically configured to: taking the reference voltage as a reference, convert the induced voltage signal into a waveform signal corresponding to the PWM drive signal to obtain the fluxgate modulation basic waveform. Thereby, the high precision and reliability of the induced voltage signal are ensured. In subsequent leakage detection, leakage analysis and leakage detection can be performed based on the offset conditions and / or fluctuation conditions of the fluxgate modulation basic waveform, thereby improving the accuracy of leakage detection.

[0027] In some embodiments, the modulation module is configured to: when the electrical device is not leaking electricity, modulate the fluxgate modulation basic waveform so that the frequency and duty cycle of the fluxgate modulation basic waveform are the same as those of the PWM drive signal, and the reference voltage is vertically at the middle position of the fluxgate modulation basic waveform. Thereby, the synchronization between the fluxgate modulation basic waveform and the PWM drive signal is ensured, and a clear reference, i.e., the reference voltage, is provided, reducing the complex calculation and processing process, making the design of leakage detection simpler and easier to implement, while maintaining high stability, and thus effectively improving the reliability and response speed of leakage detection.

[0028] In some embodiments, the power supply connection line includes a first connection line and a second connection line. When the first power supply supplies power to the electrical device through the first connection line and the second connection line, the magnitudes of the currents flowing through the first connection line and the second connection line are equal and the directions are opposite. Thereby, the electromagnetic interference to the outside is reduced, and the stability and safety of the leakage detection circuit are improved.

[0029] To achieve the above object, an embodiment of the second aspect of the present invention discloses a leakage detection method for an electrical device. The leakage detection method includes: providing a PWM drive signal and a reference voltage; outputting the PWM drive signal to the coil of the magneto-conductor to excite the magneto-conductor, so that the magneto-conductor outputs a corresponding induced voltage signal through the coil, wherein the magneto-conductor is provided with a through hole axially penetrating therethrough, the power supply connection line passes through the through hole, one end of the power supply connection line is connected to a first power supply, and the other end is connected to the electrical device, and the magneto-conductor is wound with a coil; generating a fluxgate modulation basic waveform based on the PWM drive signal, the induced voltage signal and the reference voltage; and performing leakage detection on the electrical device based on the offset and / or fluctuation of the fluxgate modulation basic waveform relative to the reference voltage.

[0030] According to the leakage detection method of the embodiment of the present invention, after the coil of the magneto-conductor receives the PWM drive signal, it can excite the magneto-conductor based on the PWM drive signal, so that the magneto-conductor outputs a corresponding induced voltage signal through the coil. Then, a fluxgate modulation basic waveform is generated according to the PWM drive signal, the reference voltage signal and the reference voltage. Then, leakage detection is performed on the electrical device according to the offset and / or fluctuation of the fluxgate modulation basic waveform relative to the reference voltage, thereby not only improving the accuracy of leakage detection, but also enhancing the safety performance of leakage detection. In addition, since the reference voltage is used as a direct reference, the complex calculation and processing process are reduced, making the design of leakage detection simpler and easier to implement, while maintaining high stability, and thus effectively improving the reliability and response speed of leakage detection.

[0031] To achieve the above object, an embodiment of the third aspect of the present invention discloses an electrical device, comprising: a leakage detection circuit as described in any one of the embodiments of the first aspect of the present invention.

[0032] In some embodiments, the electrical device comprises: a charging device. Thus, it is possible to detect and protect against possible leakage during the charging process, thereby ensuring the safety and reliability of the charging process.

[0033] In the electrical device according to the embodiment of the present invention, the PWM drive module is connected to the coil and can provide a PWM drive signal to the coil to excite the magnetic conductor, so that the magnetic conductor outputs a corresponding induced voltage signal through the coil. The PWM drive signal is also connected to the modulation module and can transmit the PWM drive signal to the modulation module. At the same time, the modulation module is also respectively connected to the reference voltage module and the coil to receive the reference voltage provided by the reference voltage module and the induced voltage signal output by the coil. In this way, the modulation module can generate a fluxgate modulation basic waveform based on the received PWM drive signal, induced voltage signal and reference voltage, and then transmit the fluxgate modulation basic waveform to the control module, so that the control module can perform leakage detection on the electrical device according to the offset and / or fluctuation of the fluxgate modulation basic waveform relative to the reference voltage, thereby not only improving the accuracy of leakage detection, but also enhancing the safety performance of the entire leakage detection circuit. In addition, since the leakage detection circuit uses the reference voltage as a direct reference, it reduces the complex calculation and processing process, makes the design of the leakage detection circuit simpler and easier to implement, while maintaining high stability, and thus effectively improves the reliability and response speed of leakage detection.

[0034] To achieve the above object, an embodiment of the fourth aspect of the present invention discloses a vehicle, comprising: an electrical device as described in the embodiment of the third aspect of the present invention.

[0035] In a vehicle according to an embodiment of the present invention, a PWM drive module is connected to a coil and can provide a PWM drive signal to the coil to excite a magnetic conductor, causing the magnetic conductor to output a corresponding induced voltage signal through the coil. The PWM drive signal is also connected to a modulation module and can transmit the PWM drive signal to the modulation module. The modulation module is also connected to a reference voltage module and the coil, respectively, to receive a reference voltage provided by the reference voltage module and the induced voltage signal output by the coil. Thus, the modulation module can generate a fluxgate modulation basic waveform based on the received PWM drive signal, the induced voltage signal, and the reference voltage. The fluxgate modulation basic waveform is then transmitted to a control module, enabling the control module to perform leakage detection on an electrical device based on the offset and / or fluctuation of the fluxgate modulation basic waveform relative to the reference voltage. This not only improves the accuracy of leakage detection but also enhances the safety performance of the entire leakage detection circuit. Furthermore, because the leakage detection circuit utilizes a reference voltage as a direct reference, complex calculations and processing processes are reduced, making the leakage detection circuit design simpler and easier to implement while maintaining high stability, thereby effectively improving the reliability and response speed of leakage detection.

[0036] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0038] Figure 1 is a schematic structural diagram of a leakage detection circuit according to an embodiment of the present invention;

[0039] Figure 2 is a schematic diagram of a basic waveform of fluxgate modulation according to an embodiment of the present invention;

[0040] Figure 3 is a schematic diagram of a basic waveform of fluxgate modulation according to another embodiment of the present invention;

[0041] Figure 4 is a schematic diagram of a leakage detection circuit according to an embodiment of the present invention;

[0042] Figure 5 is a flow chart of a leakage detection method according to an embodiment of the present invention;

[0043] Figure 6 is a structural block diagram of an electric device according to an embodiment of the present invention;

[0044] Figure 7 is a structural block diagram of a vehicle according to an embodiment of the present invention.

[0045] Reference numerals:

[0046] 1 - Leakage detection circuit;

[0047] 11 - Magnetic conductor; 12 - PWM drive module; 13 - Reference voltage module; 14 - Modulation module; 15 - Control module; 16 - First power supply; 17 - Amplification module; 18 - First connection line; 19 - Second connection line;

[0048] R1 - First resistor; R2 - Second resistor; R3 - Third resistor; R4 - Fourth resistor; R5 - Fifth resistor; R6 - Sixth resistor; R7 - Seventh resistor; R8 - Eighth resistor; R9 - Ninth resistor; R10 - Tenth resistor; R11 - Eleventh resistor; R12 - Twelfth resistor; R13 - Thirteenth resistor; R14 - Fourteenth resistor; R15 - Fifteenth resistor;

[0049] A1 - First operational amplifier; A2 - Second operational amplifier; A3 - Third operational amplifier;

[0050] 141 - Switch unit; 142 - Operational amplifier unit;

[0051] Q1 - MOS transistor; C - Capacitor; V - Second power supply;

[0052] 171 - Resistor unit;

[0053] 2 - Electrical equipment;

[0054] 3 - Vehicle. Detailed implementation manners

[0055] The embodiments of the present invention will be described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. The embodiments of the present invention will be described in detail below.

[0056] Reference is made below to Figures 1 - 4 Describe the leakage detection circuit according to an embodiment of the present invention.

[0057] Figure 1 is a schematic structural diagram of a leakage detection circuit according to an embodiment of the present invention. As Figure 1 shown, the leakage detection circuit 1 includes: a magnetic conductor 11, a PWM drive module 12, a reference voltage module 13, a modulation module 14, and a control module 15.

[0058] Among them, as Figure 1As shown in the figure, the magnetic conductor 11 is provided with a through hole penetrating along its axial direction, and the power supply connection line passes through the through hole. One end of the power supply connection line is connected to the first power supply 16, and the other end is connected to the electrical device 2. The magnetic conductor 11 is wound with a coil; one end of the PWM driving module 12 is connected to the coil, and is used to output a PWM driving signal to the coil to excite the magnetic conductor 11, so that the magnetic conductor 11 outputs a corresponding induced voltage signal through the coil; the reference voltage module 13 is used to provide a reference voltage; the modulation module 14 is respectively connected to the PWM driving module 12, the reference voltage module 13 and the coil, and is used to generate a fluxgate modulation basic waveform based on the PWM driving signal, the induced voltage signal and the reference voltage; the control module 15 is respectively connected to the modulation module 14 and the reference voltage module 13, and is used to perform leakage detection on the electrical device 2 based on the offset and / or fluctuation of the fluxgate modulation basic waveform relative to the reference voltage.

[0059] Among them, the PWM driving module 12 is an external driving circuit; the PWM driving module 12 includes, for example, but is not limited to, a single-chip microcomputer pin and an oscillation circuit.

[0060] The PWM driving signal is a square wave generated by the PWM driving module 12, and the frequency is, for example, 4.5KHz - 5KHz, and the duty cycle is, for example, 50%.

[0061] The magnetic conductor 11 is, for example, flat and annular, and is made of, for example, permalloy or iron-based amorphous material. About 20 to 45 turns of coils are wound on the surface of the magnetic conductor 11, and there is no special requirement for the winding direction of these coils, that is, either clockwise or counterclockwise direction is acceptable. This design not only ensures that the magnetic conductor 11 can effectively enhance the magnetic field signal, but also makes it easier to obtain the induced voltage signal.

[0062] In the embodiment, as Figure 1 shown, the magnetic conductor 11 is internally provided with a through hole penetrating along the axial direction, and this through hole is used for the power supply connection line to pass through. Among them, one end of the power supply connection line is connected to the first power supply 16, and the other end is connected to the electrical device 2, ensuring that the power provided by the first power supply 16 can be transmitted from the power supply connection line to the electrical device 2.

[0063] Moreover, a coil is wound on the magnetic conductor 11, and this coil is connected to the PWM driving module 12. The PWM driving module 12 can generate a PWM driving signal and output the PWM driving signal to the coil, so as to excite the magnetic conductor 11 through the PWM driving signal, generate a periodic magnetic flux change inside the coil, and then generate a corresponding induced voltage signal in the coil according to this periodic magnetic flux change, and output the induced voltage signal through the coil.

[0064] The reference voltage module 13 can provide a reference voltage, and this reference voltage is used as a reference voltage for comparison and analysis during the leakage detection process.

[0065] The modulation module 14 is respectively connected to the PWM driving module 12, the reference voltage module 13 and the coil, and can receive the induced voltage signal output by the coil, the PWM driving signal output by the PWM driving module 12, and the reference voltage provided by the reference voltage module 13. Then, based on the induced voltage signal, the PWM driving signal and the reference voltage, a fluxgate modulation basic waveform is generated.

[0066] Specifically, as Figure 2 shown, the modulation module 14, based on the received PWM driving signal and the induced voltage signal, uses the reference voltage as the reference voltage, determines the required frequency and duty cycle by using the PWM driving signal, and modulates the induced voltage signal according to the frequency and duty cycle to modulate the induced voltage signal into a fluxgate modulation basic waveform with the same frequency and duty cycle as the PWM driving signal, so as to ensure that the fluxgate modulation basic waveform is synchronized with the PWM driving signal.

[0067] The control module 15 is respectively connected to the modulation module 14 and the reference voltage module 13, and can receive the fluxgate modulation basic waveform output by the modulation module 14 and the reference voltage output by the reference voltage module 13. Similarly, the reference voltage is still used as the reference voltage. The control module 15 will perform leakage detection based on the offset and / or fluctuation of the fluxgate modulation basic waveform relative to the reference voltage, so that the control module 15 can not only quickly identify the leakage situation, but also evaluate its severity, thus not only improving the accuracy of leakage detection, but also enhancing the safety performance of the entire leakage detection circuit 1. In addition, since this design uses the reference voltage as a direct reference, it reduces the complex calculation and processing process, makes the circuit design simpler and easier to implement, while maintaining high stability, and thus effectively improves the reliability and response speed of leakage detection.

[0068] Thus, in an embodiment of the present invention, the PWM driving module 12 is connected to the coil and can provide a PWM driving signal to the coil to excite the magnetic conductor 11, so that the magnetic conductor 11 outputs a corresponding induced voltage signal through the coil. The PWM driving signal is also connected to the modulation module 14 and can transmit the PWM driving signal to the modulation module 14. At the same time, the modulation module 14 is also connected to the reference voltage module 13 and the coil respectively to receive the reference voltage provided by the reference voltage module 13 and the induced voltage signal output by the coil. In this way, the modulation module 14 can generate a fluxgate modulation basic waveform based on the received PWM driving signal, induced voltage signal and reference voltage, and then transmit the fluxgate modulation basic waveform to the control module 15, so that the control module 15 can detect the leakage of the electrical device 2 according to the offset condition and / or fluctuation condition of the fluxgate modulation basic waveform relative to the reference voltage. Thus, not only the accuracy of leakage detection is improved, but also the safety performance of the entire leakage detection circuit 1 is enhanced. In addition, since the leakage detection circuit 1 uses the reference voltage as a direct reference, the complex calculation and processing process are reduced, the design of the leakage detection circuit 1 is simpler and easier to implement, and at the same time, a high stability is maintained, thereby effectively improving the reliability and response speed of leakage detection.

[0069] In an embodiment of the present invention, the control module 15 is used to detect the leakage of the electrical device 2 based on the offset condition and / or fluctuation condition of the fluxgate modulation basic waveform relative to the reference voltage, including: when there is an offset of the fluxgate modulation basic waveform relative to the reference voltage, and / or the fluxgate modulation basic waveform fluctuates relative to the reference voltage, it is determined that the electrical device 2 has a leakage.

[0070] In the embodiment, the control module 15 analyzes the offset condition and / or fluctuation condition of the fluxgate modulation basic waveform relative to the reference voltage to implement the leakage detection of the electrical device 2. Specifically, when there is an offset of the fluxgate modulation basic waveform relative to the provided reference voltage, and / or the fluxgate modulation basic waveform fluctuates relative to the reference voltage, the control module 15 can determine that the electrical device 2 has a leakage.

[0071] Among them, the offset means that the position of the fluxgate modulation basic waveform relative to the reference voltage has changed and is no longer at the intermediate position in the normal situation without leakage; and the fluctuation means that the shape and amplitude of the waveform have abnormal changes, and these abnormal changes may all be caused by current leakage.

[0072] Once the control module 15 detects any of the above abnormal conditions, the control module 15 can determine that the electrical equipment 2 has a leakage, thereby improving the accuracy and reliability of the leakage detection. Moreover, by directly monitoring the relationship between the fluxgate modulation basic waveform and the reference voltage, the detection process is simplified, making the design of the leakage detection circuit 1 simpler and easier to implement. At the same time, a high degree of stability is ensured, effectively enhancing the safety performance of the entire leakage detection, and being able to detect and respond to potential leakage risks in a timely manner.

[0073] In an embodiment of the present invention, after the control module 15 determines that the electrical equipment 2 has a leakage, it includes: determining the leakage type of the electrical equipment 2 according to the offset condition and / or fluctuation condition of the fluxgate modulation basic waveform relative to the reference voltage.

[0074] In the embodiment, after the control module 15 determines that the electrical equipment 2 has a leakage, it further analyzes and determines the specific leakage type according to the offset condition and / or fluctuation condition of the fluxgate modulation basic waveform relative to the reference voltage, thereby providing a basis for taking targeted maintenance measures. At the same time, the response accuracy and processing efficiency of the leakage detection are improved, which helps to quickly locate the root cause of the problem and enhance the safety and reliability of the overall leakage detection circuit 1.

[0075] In an embodiment of the present invention, as Figure 3 shown, the control module 15 determines the leakage type of the electrical equipment 2 according to the offset condition and / or fluctuation condition of the fluxgate modulation basic waveform relative to the reference voltage, including: when there is an overall offset of the fluxgate modulation basic waveform relative to the reference voltage in the same longitudinal direction, it is determined that the electrical equipment 2 has a DC leakage.

[0076] In the embodiment, when the control module 15 detects that there is an overall offset of the fluxgate modulation basic waveform relative to the reference voltage in the same longitudinal direction, for example, when the fluxgate modulation basic waveform has an overall upward offset or an overall downward offset relative to the reference voltage, the control module 15 can determine that the electrical equipment 2 has a DC leakage. In this way, the control module 15 can not only identify whether there is a leakage phenomenon in the electrical equipment 2, but also further distinguish the leakage type as DC leakage, thereby providing accurate information for fault diagnosis, facilitating the adoption of targeted measures for repair, and effectively improving the safety and reliability of the leakage detection.

[0077] In an embodiment of the present invention, as Figure 3 shown, the control module 15 determines the leakage type of the electrical equipment 2 according to the offset condition and / or fluctuation condition of the fluxgate modulation basic waveform relative to the reference voltage, including: when the fluxgate modulation basic waveform fluctuates periodically relative to the reference voltage, it is determined that the electrical equipment 2 has an AC leakage.

[0078] In an embodiment, when the control module 15 detects that the fluxgate modulation basic waveform exhibits periodic fluctuations with respect to the reference voltage, the control module 15 can determine that there is AC leakage in the electrical device 2. Among them, this periodic fluctuation characteristic is manifested as the fluxgate modulation basic waveform symmetrically changing up and down around the reference voltage, reflecting the existence of a component with a fixed frequency in the induced voltage signal. This variable component is caused by the leakage of alternating current.

[0079] For example, if the waveform shows regular rises and falls, similar to the change pattern of a sine wave, this indicates the existence of AC leakage. Based on the identified fluctuations of this sine wave, the control module 15 can not only determine that there is leakage in the electrical device 2, but also accurately judge that the leakage type is AC leakage, thereby providing key information for fault diagnosis and supporting the adoption of appropriate measures for repair to ensure the safety and stability of the leakage detection circuit 1.

[0080] In an embodiment of the present invention, as Figure 3 shown, the control module 15 determines the leakage type of the electrical device 2 according to the offset and / or fluctuation of the fluxgate modulation basic waveform with respect to the reference voltage, including: when the fluxgate modulation basic waveform exhibits periodic fluctuations with respect to the reference voltage and there is an overall offset in the same longitudinal direction, it is determined that there is AC-DC superposition leakage in the electrical device 2.

[0081] In an embodiment, when the control module 15 detects that the fluxgate modulation basic waveform not only exhibits periodic fluctuations with respect to the reference voltage, but also has an overall offset in the same longitudinal direction, the control module 15 can determine that there is AC-DC superposition leakage in the electrical device 2. That is, the fluxgate modulation basic waveform not only shows regular up and down fluctuations around the reference voltage, such as similar to a sine wave, indicating the existence of an AC leakage component; but also shows an overall upward or downward offset on the reference voltage, indicating the existence of a DC leakage component. Therefore, according to the change of the fluxgate modulation basic waveform, it can be accurately judged that there is AC-DC superposition leakage in the electrical device 2, and based on the determined leakage type, precise fault diagnosis information can be provided, and targeted maintenance measures can be taken to ensure the safety and stability of the leakage detection circuit 1.

[0082] It should be noted that the greater the degree of leakage of the electrical device 2, the greater the amplitude of the offset and fluctuation of the fluxgate modulation basic waveform with respect to the reference voltage, that is, both the offset amount and the fluctuation amplitude will increase with the increase of the leakage intensity.

[0083] In an embodiment of the present invention, as Figure 1As shown, the leakage detection circuit 1 further includes: an amplification module 17. The input terminals of the amplification module 17 are respectively connected to the modulation module 14 and the reference voltage module 13, and the output terminal of the amplification module 17 is connected to the control module 15, for amplifying the fluxgate modulation basic waveform and the reference voltage.

[0084] In an embodiment, as Figure 1 shown, the input terminals of the amplification module 17 are respectively connected to the modulation module 14 and the reference voltage module 13, for receiving the fluxgate modulation basic waveform output by the modulation module 14 and the reference voltage provided by the reference voltage module 13. The amplification module 17 performs amplification processing on the received fluxgate modulation basic waveform and reference voltage to enhance the amplitude of the fluxgate modulation basic waveform. This amplification not only improves the sensitivity of leakage detection, but also ensures the accuracy and reliability of the processing of the fluxgate modulation basic waveform, enabling the control module 15 to more clearly identify and process the offset and / or fluctuation of the fluxgate modulation basic waveform relative to the reference voltage based on the amplified reference voltage, thereby ensuring the efficient operation and safety of the leakage detection circuit 1, not only improving the leakage detection accuracy, but also further enhancing the reliability and response speed of the leakage detection circuit 1.

[0085] In an embodiment of the present invention, as Figure 4 shown, the reference voltage module 13 includes: a first resistor R1, a second resistor R2, and a first operational amplifier A1. Wherein, one end of the first resistor R1 is connected to the second power supply V; one end of the second resistor R2 is connected to the other end of the first resistor R1, and the other end of the second resistor R2 is grounded; the non-inverting input terminal of the first operational amplifier A1 is respectively connected to the other end of the first resistor R1 and one end of the second resistor R2, the inverting input terminal of the first operational amplifier A1 is connected to the output terminal of the first operational amplifier A1, and the output terminal of the first operational amplifier A1 is respectively connected to the modulation module 14 and the amplification module 17, for outputting a reference voltage to the modulation module 14 and the amplification module 17.

[0086] Wherein, the second power supply V includes, for example, but is not limited to, 2.5V, 3.3V, 5V; the reference voltage is half of the second power supply V. For example, when the second power supply V is 5V, the reference voltage is 2.5V.

[0087] In an embodiment, as Figure 4 shown, one end of the first resistor R1 is connected to the second power supply V, the other end of the first resistor R1 is connected to one end of the second resistor R2, and the other end of the second resistor R2 is grounded. In this way, through the voltage division of the first resistor R1 and the second resistor R2, a reference voltage that is half of the second power supply V can be obtained at the node between the first resistor R1 and the second resistor R2.

[0088] The non-inverting input terminal of the first operational amplifier A1 is respectively connected to the other end of the first resistor R1 and one end of the second resistor R2, that is, the first operational amplifier A1 is connected to the node between the first resistor R1 and the second resistor R2, so as to receive the reference voltage obtained through the voltage division of the first resistor R1 and the second resistor R2.

[0089] To determine the stable output of the reference voltage, the inverting input terminal of the first operational amplifier A1 is connected to the output terminal of the first operational amplifier A1 to form a voltage follower. This can not only keep the input reference voltage unchanged, but also enhance its driving ability, making the output reference voltage more stable and reliable.

[0090] The output terminal of the first operational amplifier A1 is respectively connected to the modulation module 14 and the amplification module 17 to provide a stable reference voltage to the modulation module 14 and the amplification module 17. This ensures that both the modulation module 14 and the amplification module 17 can operate based on the same accurate and stable reference voltage, thereby improving the accuracy and reliability of the entire leakage detection circuit 1.

[0091] In an embodiment of the present invention, as Figure 4 shown, the modulation module 14 includes: a switch unit 141 and an operational amplifier unit 142. Among them, the first end of the switch unit 141 is connected to one end of the coil, the second end of the switch unit 141 is connected to the PWM driving module 12 ( Figure 4 not shown in the figure), and the second end of the switch unit 141 is also grounded; the non-inverting input terminal of the operational amplifier unit 142 is respectively connected to the third end of the switch unit 141 and the output terminal of the first operational amplifier A1, the inverting input terminal of the operational amplifier unit 142 is respectively connected to the second power supply V and one end of the coil, the inverting input terminal of the operational amplifier unit 142 is also grounded, and the output terminal of the operational amplifier unit 142 is respectively connected to the amplification module 17 and one end of the coil.

[0092] In the embodiment, as Figure 4 shown, the first end of the switch unit 141 is connected to one end of the coil, and the second end of the switch unit 141 is connected to the PWM driving module 12 to receive the PWM driving signal Vin provided by the PWM driving module 12. In this way, the switch unit 141 can receive the PWM driving signal Vin.

[0093] The non-inverting input terminal of the operational amplifier unit 142 is connected to the third terminal of the switch unit 141, so that the PWM drive signal Vin can be transmitted to the operational amplifier unit 142 through the third terminal of the switch unit 141. In addition, the non-inverting input terminal of the operational amplifier unit 142 is also connected to the output terminal of the first operational amplifier A1 to receive the reference voltage output by the first operational amplifier A1. The inverting input terminal of the operational amplifier unit 142 is respectively connected to the second power supply V and one end of the coil to receive the induced voltage signal output by the coil. The inverting input terminal of the operational amplifier unit 142 is also grounded. Thus, the operational amplifier unit 142 can modulate the induced voltage signal into a fluxgate modulation basic waveform having the same frequency and duty cycle as the PWM drive signal Vin based on the received PWM drive signal Vin, induced voltage signal, and reference voltage, where the reference voltage is used as a reference voltage.

[0094] The output terminal of the operational amplifier unit 142 is connected to the amplification module 17 and one end of the coil. The fluxgate modulation basic waveform processed by the operational amplifier unit 142 can be further amplified and enhanced by the amplification module 17, facilitating the leakage analysis and leakage detection by the control module 15 based on the amplified fluxgate modulation basic waveform, thereby improving the sensitivity and accuracy of the leakage detection.

[0095] In an embodiment of the present invention, as Figure 4 shown, the switch unit 141 includes: MOS transistor Q1, third resistor R3, and fourth resistor R4; one end of the third resistor R3 is connected to one end of the coil, and the other end of the third resistor R3 is respectively connected to the gate of the MOS transistor Q1 and the PWM drive module 12; the drain of the MOS transistor Q1 is connected to the PWM drive module 12 through the fourth resistor R4 ( Figure 4 not shown in the figure), the drain of the MOS transistor Q1 is also grounded, and the source of the MOS transistor Q1 is connected to the non-inverting input terminal of the operational amplifier unit 142.

[0096] In the embodiment, as Figure 4 shown, one end of the third resistor R3 is connected to one end of the coil, and the other end of the third resistor R3 is connected to the PWM drive module 12 to receive the PWM drive signal Vin provided by the PWM drive module 12. At the same time, the other end of the third resistor R3 is also connected to the gate of the MOS transistor Q1, so that the PWM drive signal can excite the coil, thereby generating a periodic magnetic flux change inside the coil and outputting a corresponding induced voltage signal.

[0097] The drain of the MOS transistor Q1 is connected to the PWM drive module 12 through the fourth resistor R4 to receive the PWM drive signal Vin generated by the PWM drive module 12. At the same time, the drain of the MOS transistor Q1 is also grounded, which not only ensures the safety and stability of the entire leakage detection circuit 1 but also provides a reliable path for the transmission of the PWM drive signal Vin.

[0098] The source electrode of MOS transistor Q1 is connected to the non-inverting input terminal of operational amplifier unit 142, so as to transmit the PWM driving signal Vin to the operational amplifier unit 142 through the working state (i.e., conduction or cut-off) of MOS transistor Q1.

[0099] In this way, the switching unit 141 effectively controls the transmission paths of the PWM driving signal Vin and the induced voltage signal, ensuring that the PWM driving signal Vin and the induced voltage signal can be accurately transmitted to the operational amplifier unit 142.

[0100] In one embodiment of the present invention, as Figure 4 shown, the operational amplifier unit 142 includes: a second operational amplifier A2, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, and a ninth resistor R9; the non-inverting input terminal of the second operational amplifier A2 is connected to the output terminal of the first operational amplifier A1 through the fifth resistor R5; the non-inverting input terminal of the second operational amplifier A2 is also connected to the source electrode of MOS transistor Q1 through the sixth resistor R6; the inverting input terminal of the second operational amplifier A2 is connected to the second power supply V through the seventh resistor R7, the inverting input terminal of the second operational amplifier A2 is grounded through the eighth resistor R8, and the inverting input terminal of the second operational amplifier A2 is also connected to one end of the coil through the ninth resistor R9; the output terminal of the second operational amplifier A2 is respectively connected to one end of the coil and the amplification module 17.

[0101] In the embodiment, as Figure 4 shown, the non-inverting input terminal of the second operational amplifier A2 is connected to the output terminal of the first operational amplifier A1 through the fifth resistor R5 to receive the reference voltage output by the first operational amplifier A1; at the same time, the non-inverting input terminal of the second operational amplifier A2 is also connected to the source electrode of MOS transistor Q1 through the sixth resistor R6 for receiving the PWM driving signal Vin through the working state of MOS transistor Q1. For example, when the PWM driving module 12 provides the PWM driving signal Vin to the drain electrode of MOS transistor Q1 through the fourth resistor R4, MOS transistor Q1 is turned on. At this time, the PWM driving signal Vin is output to the non-inverting input terminal of the second operational amplifier A2 through the source electrode of MOS transistor Q1 and the sixth resistor R6.

[0102] In addition, the inverting input terminal of the second operational amplifier A2 is connected to the second power supply V through the seventh resistor R7 and grounded through the eighth resistor R8, which provides a stable reference point for the inverting input terminal of the second operational amplifier A2. At the same time, the inverting input terminal of the second operational amplifier A2 is also connected to one end of the coil through the ninth resistor R9 to receive the induced voltage signal from the coil.

[0103] The output terminal of the second operational amplifier A2 is respectively connected to one end of the coil and the amplification module 17. After receiving the PWM drive signal Vin, the induced voltage signal, and the reference voltage, the second operational amplifier A2 will modulate the induced voltage signal based on the PWM drive signal Vin. Among them, the reference voltage serves as a reference voltage, and then a fluxgate modulation basic waveform is generated. The fluxgate modulation basic waveform not only includes the frequency and duty cycle characteristics of the PWM drive signal Vin but also reflects the change of the induced voltage signal. At the same time, with the reference voltage as a reference, the accuracy and stability of the fluxgate modulation basic waveform are ensured.

[0104] Finally, the fluxgate modulation basic waveform processed by the second operational amplifier A2 is transmitted to the amplification module 17 through its output terminal to further amplify the fluxgate modulation basic waveform and ensure high sensitivity and reliability in the subsequent leakage detection process.

[0105] In an embodiment of the present invention, as Figure 4 shown, the modulation module 14 further includes: a capacitor C. One end of the capacitor C is connected to one end of the ninth resistor R9, and the other end of the capacitor C is connected to the other end of the ninth resistor R9.

[0106] In the embodiment, as Figure 4 shown, one end of the capacitor C is connected to one end of the ninth resistor R9, and the other end of the capacitor C is connected to the other end of the ninth resistor R9, that is, the capacitor C is connected in parallel with the ninth resistor R9. Specifically, in the modulation module 14, one end of the ninth resistor R9 receives the induced voltage signal from the coil, and the other end is connected to the inverting input terminal of the second operational amplifier A2. By connecting the capacitor C in parallel, the induced voltage signal entering the second operational amplifier A2 can be filtered to eliminate high-frequency noise or other interferences, thereby ensuring that the induced voltage signal transmitted to the second operational amplifier A2 is purer and more stable. Furthermore, it helps to improve the quality of the fluxgate modulation basic waveform, making the subsequent leakage detection more accurate and reliable, and at the same time enhancing the anti-interference ability of the entire leakage detection circuit 1.

[0107] In an embodiment of the present invention, as Figure 4 shown, the amplification module 17 includes: a third operational amplifier A3, a tenth resistor R10, an eleventh resistor R11, and a resistor unit 171; the non-inverting input terminal of the third operational amplifier A3 is respectively connected to the output terminal of the second operational amplifier A2, the output terminal of the first operational amplifier A1, and the other end of the coil through the resistor unit 171; the inverting input terminal of the third operational amplifier A3 is connected to the output terminal of the first operational amplifier A1 through the tenth resistor R10. The inverting input terminal of the third operational amplifier A3 is also connected to one end of the eleventh resistor R11, and the output terminal of the third operational amplifier A3 is connected to the control module 15; the other end of the eleventh resistor R11 is connected to the control module 15.

[0108] In an embodiment, as Figure 4 shown, the non-inverting input terminal of the third operational amplifier A3 is respectively connected to the output terminal of the second operational amplifier A2, the output terminal of the first operational amplifier A1, and the other end of the coil through the resistor unit 171, so as to receive the fluxgate modulation basic waveform.

[0109] The inverting input terminal of the third operational amplifier A3 is connected to the output terminal of the first operational amplifier A1 through the tenth resistor R10 to receive the reference voltage, and the inverting input terminal of the third operational amplifier A3 is also connected to one end of the eleventh resistor R11, so that the amplification factor can be determined based on the tenth resistor R10 and the eleventh resistor R11, enabling the third operational amplifier A3 to amplify the fluxgate modulation basic waveform and the reference voltage based on this amplification factor. The output terminal of the third operational amplifier A3 is connected to the control module 15 for transmitting the amplified reference voltage and the fluxgate modulation basic waveform. At the same time, the other end of the eleventh resistor R11 is also connected to the control module 15 to form a feedback path, which helps to stabilize the gain and improve the quality of the reference voltage and the fluxgate modulation basic waveform.

[0110] Among them, the third operational amplifier A3 amplifies the input reference voltage and the fluxgate modulation basic waveform based on the resistance ratio of the tenth resistor R10 and the eleventh resistor R11. Specifically, the tenth resistor R10 and the eleventh resistor R11 jointly determine the amplification factor, and the resistance value of the tenth resistor R10 is less than that of the eleventh resistor R11. For example, if the resistance value of the tenth resistor R10 is 10Ω and the resistance value of the eleventh resistor R11 is 20Ω, then the resistance ratio of the tenth resistor R10 and the eleventh resistor R11 is obtained as 2, thereby determining the amplification factor as 2.

[0111] Thus, the third operational amplifier A3 can effectively amplify the fluxgate modulation basic waveform and the reference voltage by two times, ensuring that even in the case of minute offset and / or fluctuation, the amplified reference voltage and the fluxgate modulation basic waveform can be accurately obtained. The amplified reference voltage and the fluxgate modulation basic waveform are transmitted to the control module 15 through the output terminal of the third operational amplifier A3, enabling the control module 15 to perform accurate leakage analysis and leakage detection based on the amplified fluxgate modulation basic waveform and the reference voltage, thereby not only improving the sensitivity and accuracy of leakage detection, but also enhancing the reliability and stability of the entire leakage detection circuit 1.

[0112] In an embodiment of the present invention, as Figure 4As shown, the resistance unit 171 includes: the twelfth resistor R12, the thirteenth resistor R13, the fourteenth resistor R14, and the fifteenth resistor R15; one end of the twelfth resistor R12 is respectively connected to the output end of the second operational amplifier A2 and one end of the coil, and the other end of the twelfth resistor R12 is respectively connected to one end of the thirteenth resistor R13 and the output end of the first operational amplifier A1; the other end of the thirteenth resistor R13 is connected to one end of the fourteenth resistor R14; the other end of the fourteenth resistor R14 is respectively connected to the other end of the coil and one end of the fifteenth resistor R15; the other end of the fifteenth resistor R15 is connected to the positive-phase input end of the third operational amplifier A3.

[0113] In an embodiment, as Figure 4 shown, one end of the twelfth resistor R12 is respectively connected to the output end of the second operational amplifier A2 and one end of the coil to receive the fluxgate modulation basic waveform, while the other end of the twelfth resistor R12 is respectively connected to one end of the thirteenth resistor R13 and the output end of the first operational amplifier A1 to form a circuit transmission path with the thirteenth resistor R13, receive the reference voltage, and simultaneously transmit the fluxgate modulation basic waveform and the reference voltage.

[0114] The other end of the thirteenth resistor R13 is connected to one end of the fourteenth resistor R14 to form a part of the circuit transmission path. Then, the other end of the fourteenth resistor R14 is simultaneously connected to the other end of the coil and one end of the fifteenth resistor R15, and the other end of the fifteenth resistor R15 is connected to the positive-phase input end of the third operational amplifier A3. In this way, a circuit transmission path is formed through the twelfth resistor R12, the thirteenth resistor R13, the fourteenth resistor R14, and the fifteenth resistor R15 to transmit the fluxgate modulation basic waveform and the reference voltage to the third operational amplifier A3 for amplification processing.

[0115] In this way, the resistance unit 171 not only realizes the transmission of the fluxgate modulation basic waveform and the reference voltage, but also ensures that the fluxgate modulation basic waveform and the reference voltage are properly divided and filtered before entering the third operational amplifier A3, thereby improving the quality and stability of the fluxgate modulation basic waveform and the reference voltage, and further enhancing the reliability and accuracy of the entire leakage detection circuit 1.

[0116] In an embodiment of the present invention, as Figure 2 shown, the modulation module 14 is specifically configured to: convert the induced voltage signal into a waveform signal corresponding to the PWM drive signal with the reference voltage as a reference to obtain the fluxgate modulation basic waveform.

[0117] In an embodiment, as Figure 2As shown, the modulation module 14 can accurately adjust the induced voltage signal by using a stable reference voltage as a reference, so that it is modulated according to the frequency and duty cycle characteristics of the PWM drive signal, and outputs a fluxgate modulation basic waveform. This ensures the high precision and reliability of the induced voltage signal. In subsequent leakage detection, leakage analysis and leakage detection can be performed based on the offset and / or fluctuation of the fluxgate modulation basic waveform relative to the reference voltage, thereby improving the accuracy of leakage detection.

[0118] In an embodiment of the present invention, the modulation module 14 is configured to: when the electrical device 2 is not leaking, modulate the fluxgate modulation basic waveform so that the frequency and duty cycle of the fluxgate modulation basic waveform are the same as those of the PWM drive signal, and the reference voltage is longitudinally located at the middle position of the fluxgate modulation basic waveform.

[0119] In the embodiment, when the electrical device 2 is not leaking, the fluxgate modulation basic waveform is modulated so that the frequency and duty cycle of the fluxgate modulation basic waveform are exactly the same as those of the PWM drive signal, and at the same time, it is ensured that the reference voltage is longitudinally located at the middle position of the fluxgate modulation basic waveform. This method not only ensures the synchronization of the fluxgate modulation basic waveform with the PWM drive signal, but also provides a clear reference, that is, the reference voltage, reduces complex calculation and processing processes, makes the design of leakage detection simpler and easier to implement, and at the same time maintains high stability, thereby effectively improving the reliability and response speed of leakage detection.

[0120] As Figure 3 shown, when the electrical device 2 is not leaking, the reference voltage is longitudinally located at the middle position of the fluxgate modulation basic waveform. Once the electrical device 2 has a leakage, the fluxgate modulation basic waveform is overall offset and / or periodically fluctuates relative to the reference voltage, so that the reference voltage is not longitudinally located at the middle position of the fluxgate modulation basic waveform. Thus, leakage detection is performed according to the fluctuation and / or offset of the fluxgate modulation basic waveform relative to the reference voltage, improving the accuracy of leakage detection.

[0121] In an embodiment of the present invention, in combination with Figure 1 and Figure 4 shown, the power supply connection line includes a first connection line 18 and a second connection line 19. When the first power supply 16 supplies power to the electrical device 2 through the first connection line 18 and the second connection line 19, the magnitudes of the currents flowing through the first connection line 18 and the second connection line 19 are equal and the directions are opposite.

[0122] In the embodiment, in combination with Figure 1 and Figure 4As shown, one end of the first connection line 18 and the second connection line 19 is connected to the first power supply 16, and the other ends of the first connection line 18 and the second connection line 19 pass through an axially penetrating through-hole formed inside the magnetic conductor 11 and are connected to the electrical device 2.

[0123] When the first power supply 16 supplies power to the electrical device 2 through the first connection line 18 and the second connection line 19, the magnitudes of the currents flowing through the first connection line 18 and the second connection line 19 are equal but the directions are opposite, ensuring that under normal operating conditions, that is, when the electrical device 2 does not leak electricity, the currents flowing through the first connection line 18 and the second connection line 19 cancel each other out, thereby reducing the electromagnetic interference to the outside world and improving the stability and safety of the leakage detection circuit 1.

[0124] However, once the currents flowing through the first connection line 18 and the second connection line 19 are not equal, the magnetic flux in the coil is no longer completely cancelled out, causing the magnetic conductor 11 to tend to saturate. This change in magnetic flux will cause the impedance of the coil wound around the surface of the magnetic conductor 11 to decrease. By detecting the change in the impedance of the coil, and then outputting an induced voltage signal based on the change in magnetic flux, the current imbalance can be identified according to the induced voltage signal, thereby achieving effective detection of leakage.

[0125] According to the leakage detection circuit 1 of the embodiment of the present invention, the PWM driving module 12 is connected to the coil and can provide a PWM driving signal to the coil to excite the magnetic conductor 11, so that the magnetic conductor 11 outputs a corresponding induced voltage signal through the coil. The PWM driving signal is also connected to the modulation module 14 and can transmit the PWM driving signal to the modulation module 14. At the same time, the modulation module 14 is also respectively connected to the reference voltage module 13 and the coil to receive the reference voltage provided by the reference voltage module 13 and the induced voltage signal output by the coil. In this way, the modulation module 14 can generate a fluxgate modulation basic waveform based on the received PWM driving signal, induced voltage signal and reference voltage, and then transmit the fluxgate modulation basic waveform to the control module 15, so that the control module 15 can perform leakage detection on the electrical device 2 according to the offset and / or fluctuation of the fluxgate modulation basic waveform relative to the reference voltage, thereby not only improving the accuracy of leakage detection, but also enhancing the safety performance of the entire leakage detection circuit 1. In addition, since the leakage detection circuit 1 uses the reference voltage as a direct reference, reducing the complex calculation and processing process, the leakage detection circuit 1 is designed to be simpler and easier to implement, while maintaining high stability, thereby effectively improving the reliability and response speed of leakage detection.

[0126] A further embodiment of the present invention also discloses a leakage detection method, wherein the leakage detection method is used for an electrical device.

[0127] As Figure 5As shown, it is a flowchart of the leakage detection method according to an embodiment of the present invention, and the method at least includes steps S1 to S4.

[0128] Step S1, provide a PWM drive signal and a reference voltage.

[0129] Step S2, output a PWM drive signal to the coil of the magnetic conductor to excite the magnetic conductor, so that the magnetic conductor outputs a corresponding induced voltage signal through the coil. Among them, the magnetic conductor is provided with a through hole axially penetrating therethrough, and the power supply connection line passes through the through hole. One end of the power supply connection line is connected to the first power supply, and the other end is connected to the electrical device, and the magnetic conductor is wound with a coil.

[0130] Step S3, generate a fluxgate modulation basic waveform based on the PWM drive signal, the induced voltage signal and the reference voltage.

[0131] Step S4, perform leakage detection on the electrical device based on the offset situation and / or fluctuation situation of the fluxgate modulation basic waveform relative to the reference voltage.

[0132] In an embodiment of the present invention, performing leakage detection on the electrical device based on the offset situation and / or fluctuation situation of the fluxgate modulation basic waveform relative to the reference voltage includes: when the fluxgate modulation basic waveform has an offset relative to the reference voltage, and / or the fluxgate modulation basic waveform fluctuates relative to the reference voltage, it is determined that the electrical device has a leakage.

[0133] In an embodiment of the present invention, after it is determined that the electrical device has a leakage, it includes: determining the leakage type of the electrical device according to the offset situation and / or fluctuation situation of the fluxgate modulation basic waveform relative to the reference voltage.

[0134] In an embodiment of the present invention, determining the leakage type of the electrical device according to the offset situation and / or fluctuation situation of the fluxgate modulation basic waveform relative to the reference voltage includes: when the fluxgate modulation basic waveform has an overall offset in the same direction longitudinally relative to the reference voltage, it is determined that the electrical device has a DC leakage.

[0135] In an embodiment of the present invention, determining the leakage type of the electrical device according to the offset situation and / or fluctuation situation of the fluxgate modulation basic waveform relative to the reference voltage includes: when the fluxgate modulation basic waveform fluctuates periodically relative to the reference voltage, it is determined that the electrical device has an AC leakage.

[0136] In an embodiment of the present invention, determining the leakage type of the electrical device according to the offset situation and / or fluctuation situation of the fluxgate modulation basic waveform relative to the reference voltage includes: when the fluxgate modulation basic waveform fluctuates periodically and has an overall offset in the same direction longitudinally relative to the reference voltage, it is determined that the electrical device has an AC-DC superimposed leakage.

[0137] In one embodiment of the present invention, the leakage detection method further includes: using the reference voltage as a reference, converting the induced voltage signal into a waveform signal corresponding to the PWM driving signal to obtain the fluxgate modulation basic waveform.

[0138] In one embodiment of the present invention, the leakage detection method further includes: when the electrical device is not leaking, modulating the fluxgate modulation basic waveform so that the frequency and duty cycle of the fluxgate modulation basic waveform are the same as those of the PWM driving signal, and the reference voltage is longitudinally in the middle position of the fluxgate modulation basic waveform.

[0139] In one embodiment of the present invention, the power supply connection line includes a first connection line and a second connection line. When the first power supply supplies power to the electrical device through the first connection line and the second connection line, the magnitudes of the currents flowing through the first connection line and the second connection line are equal and the directions are opposite.

[0140] According to the leakage detection method of the embodiment of the present invention, after the coil of the magnetic conductor receives the PWM driving signal, it can excite the magnetic conductor based on the PWM driving signal, so that the magnetic conductor outputs a corresponding induced voltage signal through the coil. Then, according to the PWM driving signal, the reference voltage signal and the reference voltage, the fluxgate modulation basic waveform is generated. Then, according to the offset and / or fluctuation of the fluxgate modulation basic waveform relative to the reference voltage, the electrical device is subjected to leakage detection, thereby not only improving the accuracy of leakage detection, but also enhancing the safety performance of leakage detection. In addition, since the reference voltage is used as a direct reference, complex calculation and processing processes are reduced, making the design of leakage detection simpler and easier to implement, while maintaining high stability, thereby effectively improving the reliability and response speed of leakage detection.

[0141] A further embodiment of the present invention also discloses an electrical device.

[0142] As Figure 6 shown, the electrical device 2 includes the leakage detection circuit 1 described in the above embodiment of the present invention.

[0143] In one embodiment of the present invention, the electrical device 2 includes: a charging device.

[0144] In the embodiment, the charging device mainly converts the electric energy provided by the first power supply 16 into an energy form suitable for use by the electrical device 2 to detect and protect possible leakage during the charging process, thereby ensuring the safety and reliability of the charging process.

[0145] According to the electrical device 2 of an embodiment of the present invention, the PWM driving module 12 is connected to the coil and can provide a PWM driving signal to the coil to excite the magnetic conductor 11, so that the magnetic conductor 11 outputs a corresponding induced voltage signal through the coil. The PWM driving signal is also connected to the modulation module 14 and can transmit the PWM driving signal to the modulation module 14. At the same time, the modulation module 14 is also respectively connected to the reference voltage module 13 and the coil to receive the reference voltage provided by the reference voltage module 13 and the induced voltage signal output by the coil. In this way, the modulation module 14 can generate a fluxgate modulation basic waveform based on the received PWM driving signal, induced voltage signal and reference voltage, and then transmit the fluxgate modulation basic waveform to the control module 15, so that the control module 15 can perform leakage detection on the electrical device 2 according to the offset and / or fluctuation of the fluxgate modulation basic waveform relative to the reference voltage, thereby not only improving the accuracy of leakage detection, but also enhancing the safety performance of the entire leakage detection circuit 1. In addition, since the leakage detection circuit 1 uses the reference voltage as a direct reference, the complex calculation and processing process are reduced, the design of the leakage detection circuit 1 is simpler and easier to implement, and at the same time, a high stability is maintained, thereby effectively improving the reliability and response speed of leakage detection.

[0146] A further embodiment of the present invention also discloses a vehicle.

[0147] In some embodiments, as Figure 7 shown, the vehicle 3 includes the electrical device 2 described in the above embodiment of the present invention.

[0148] According to the vehicle 3 of an embodiment of the present invention, the PWM driving module 12 is connected to the coil and can provide a PWM driving signal to the coil to excite the magnetic conductor 11, so that the magnetic conductor 11 outputs a corresponding induced voltage signal through the coil. The PWM driving signal is also connected to the modulation module 14 and can transmit the PWM driving signal to the modulation module 14. At the same time, the modulation module 14 is also respectively connected to the reference voltage module 13 and the coil to receive the reference voltage provided by the reference voltage module 13 and the induced voltage signal output by the coil. In this way, the modulation module 14 can generate a fluxgate modulation basic waveform based on the received PWM driving signal, induced voltage signal and reference voltage, and then transmit the fluxgate modulation basic waveform to the control module 15, so that the control module 15 can perform leakage detection on the electrical device 2 according to the offset and / or fluctuation of the fluxgate modulation basic waveform relative to the reference voltage, thereby not only improving the accuracy of leakage detection, but also enhancing the safety performance of the entire leakage detection circuit 1. In addition, since the leakage detection circuit 1 uses the reference voltage as a direct reference, the complex calculation and processing process are reduced, the design of the leakage detection circuit 1 is simpler and easier to implement, and at the same time, a high stability is maintained, thereby effectively improving the reliability and response speed of leakage detection.

[0149] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example.

[0150] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and purposes of the present invention, and the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A leakage detection circuit, characterized in that, For an electrical device, the leakage detection circuit includes: A magnetic conductor having a through hole axially penetrating therethrough, a power supply connection line passing through the through hole, one end of the power supply connection line being connected to a first power supply, and the other end being connected to the electrical device, and a coil wound around the magnetic conductor; A PWM driving module having one end connected to the coil for outputting a PWM driving signal to the coil to excite the magnetic conductor so that the magnetic conductor outputs a corresponding induced voltage signal through the coil; A reference voltage module for providing a reference voltage; A modulation module connected to the PWM driving module, the reference voltage module and the coil respectively for generating a fluxgate modulation basic waveform based on the PWM driving signal, the induced voltage signal and the reference voltage. Specifically, the modulation module is configured to: based on the received PWM driving signal and the induced voltage signal, use the reference voltage as a reference voltage, use the PWM driving signal to determine the required frequency and duty cycle, and modulate the induced voltage signal according to the frequency and the duty cycle to modulate the induced voltage signal into the fluxgate modulation basic waveform having the same frequency and duty cycle as the PWM driving signal; A control module connected to the modulation module and the reference voltage module respectively for performing leakage detection on the electrical device based on the offset condition and / or fluctuation condition of the fluxgate modulation basic waveform with respect to the reference voltage.

2. The leakage detection circuit according to claim 1, wherein The control module is configured to perform leakage detection on the electrical device based on the offset condition and / or fluctuation condition of the fluxgate modulation basic waveform with respect to the reference voltage, including: When there is an offset of the fluxgate modulation basic waveform with respect to the reference voltage and / or the fluxgate modulation basic waveform fluctuates with respect to the reference voltage, it is determined that the electrical device has a leakage.

3. The leakage detection circuit according to claim 2, wherein, After the control module determines that the electrical device has a leakage, it includes: Determining the leakage type of the electrical device according to the offset condition and / or fluctuation condition of the fluxgate modulation basic waveform with respect to the reference voltage.

4. The leakage detection circuit according to claim 3, characterized in that, The control module determines the leakage type of the electrical device according to the offset condition and / or fluctuation condition of the fluxgate modulation basic waveform with respect to the reference voltage, including: When there is an overall offset of the fluxgate modulation basic waveform with respect to the reference voltage in the same longitudinal direction, it is determined that the electrical device has a DC leakage.

5. The leakage detection circuit according to claim 3, wherein The control module determines the leakage type of the electrical device according to the offset condition and / or fluctuation condition of the fluxgate modulation basic waveform with respect to the reference voltage, including: When the fluxgate modulation basic waveform fluctuates periodically with respect to the reference voltage, it is determined that the electrical device has an AC leakage.

6. The leakage detection circuit according to claim 3, wherein The control module determines the leakage type of the electrical device according to the offset condition and / or fluctuation condition of the fluxgate modulation basic waveform with respect to the reference voltage, including: When the magnetic flux gate modulation basic waveform fluctuates periodically relative to the reference voltage and there is an overall offset in the same longitudinal direction, it is determined that there is AC-DC superposition leakage in the electrical equipment.

7. The leakage detection circuit according to claim 1, wherein It further includes: An amplification module, the input end of the amplification module is respectively connected to the modulation module and the reference voltage module, and the output end of the amplification module is connected to the control module, for amplifying the magnetic flux gate modulation basic waveform and the reference voltage.

8. The leakage detection circuit according to claim 7, wherein, The reference voltage module includes: A first resistor, one end of the first resistor is connected to the second power supply; A second resistor, one end of the second resistor is connected to the other end of the first resistor, and the other end of the second resistor is grounded; A first operational amplifier, the non-inverting input terminal of the first operational amplifier is respectively connected to the other end of the first resistor and one end of the second resistor, the inverting input terminal of the first operational amplifier is connected to the output terminal of the first operational amplifier, and the output terminal of the first operational amplifier is respectively connected to the modulation module and the amplification module, for outputting the reference voltage to the modulation module and the amplification module.

9. The leakage detection circuit according to claim 8, wherein The modulation module includes: A switch unit, the first end of the switch unit is connected to one end of the coil, the second end of the switch unit is connected to the PWM driving module, and the second end of the switch unit is also grounded; An operational amplifier unit, the non-inverting input terminal of the operational amplifier unit is respectively connected to the third end of the switch unit and the output terminal of the first operational amplifier, the inverting input terminal of the operational amplifier unit is respectively connected to the second power supply and one end of the coil, the inverting input terminal of the operational amplifier unit is also grounded, and the output terminal of the operational amplifier unit is respectively connected to the amplification module and one end of the coil.

10. The leakage detection circuit according to claim 9, wherein, The switch unit includes: a MOS transistor, a third resistor, and a fourth resistor; One end of the third resistor is connected to one end of the coil, and the other end of the third resistor is connected to the gate of the MOS transistor and the PWM driving module; The drain of the MOS transistor is connected to the PWM driving module through the fourth resistor, the drain of the MOS transistor is also grounded, and the source of the MOS transistor is connected to the non-inverting input terminal of the operational amplifier unit.

11. The leakage detection circuit according to claim 10, characterized in that, The operational amplifier unit includes: a second operational amplifier, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, and a ninth resistor; The non-inverting input terminal of the second operational amplifier is connected to the output terminal of the first operational amplifier through the fifth resistor; The non-inverting input terminal of the second operational amplifier is also connected to the source of the MOS transistor through the sixth resistor; The inverting input terminal of the second operational amplifier is connected to the second power supply through the seventh resistor, the inverting input terminal of the second operational amplifier is grounded through the eighth resistor, and the inverting input terminal of the second operational amplifier is also connected to one end of the coil through the ninth resistor; The output terminal of the second operational amplifier is respectively connected to one end of the coil and the amplification module.

12. The leakage detection circuit according to claim 11, wherein, The modulation module further includes: A capacitor, one end of the capacitor is connected to one end of the ninth resistor, and the other end of the capacitor is connected to the other end of the ninth resistor.

13. The leakage detection circuit according to claim 12, wherein The amplification module includes: a third operational amplifier, a tenth resistor, an eleventh resistor, and a resistor unit; The non-inverting input terminal of the third operational amplifier is respectively connected to the output terminal of the second operational amplifier, the output terminal of the first operational amplifier, and the other end of the coil through the resistor unit; The inverting input terminal of the third operational amplifier is connected to the output terminal of the first operational amplifier through the tenth resistor. The inverting input terminal of the third operational amplifier is further connected to one end of the eleventh resistor, and the output terminal of the third operational amplifier is connected to the control module; The other end of the eleventh resistor is connected to the control module.

14. The leakage detection circuit according to claim 13, wherein The resistor unit includes: a twelfth resistor, a thirteenth resistor, a fourteenth resistor, and a fifteenth resistor; One end of the twelfth resistor is respectively connected to the output terminal of the second operational amplifier and one end of the coil. The other end of the twelfth resistor is respectively connected to one end of the thirteenth resistor and the output terminal of the first operational amplifier; The other end of the thirteenth resistor is connected to one end of the fourteenth resistor; The other end of the fourteenth resistor is respectively connected to the other end of the coil and one end of the fifteenth resistor; The other end of the fifteenth resistor is connected to the non-inverting input terminal of the third operational amplifier.

15. The leakage detection circuit according to claim 1, characterized in that, The modulation module is used for: When the electrical device is not leaking electricity, modulating the fluxgate modulation basic waveform so that the frequency and duty cycle of the fluxgate modulation basic waveform are the same as those of the PWM drive signal, and making the reference voltage be in the middle position of the fluxgate modulation basic waveform longitudinally.

16. The leakage detection circuit according to claim 1, characterized in that, The power supply connection line includes a first connection line and a second connection line. When the first power supply supplies power to the electrical device through the first connection line and the second connection line, the magnitudes of the currents flowing through the first connection line and the second connection line are equal and the directions are opposite.

17. A leakage detection method, characterized in that, For an electrical device, the leakage detection method includes: Providing a PWM drive signal and a reference voltage; Outputting the PWM drive signal to the coil of the magnetic conductor to excite the magnetic conductor, so that the magnetic conductor outputs a corresponding induced voltage signal through the coil. Wherein, the magnetic conductor is provided with a through hole axially penetrating through it, the power supply connection line passes through the through hole, one end of the power supply connection line is connected to a first power supply, the other end is connected to the electrical device, and the magnetic conductor is wound with a coil; Generating a fluxgate modulation basic waveform based on the PWM drive signal, the induced voltage signal, and the reference voltage, specifically including: based on the received PWM drive signal and the induced voltage signal, using the reference voltage as a reference voltage, using the PWM drive signal to determine the required frequency and duty cycle, and modulating the induced voltage signal according to the frequency and the duty cycle to modulate the induced voltage signal into the fluxgate modulation basic waveform having the same frequency and duty cycle as the PWM drive signal; Performing leakage detection on the electrical device based on the offset situation and / or fluctuation situation of the fluxgate modulation basic waveform relative to the reference voltage.

18. An electrical device, characterized in that, Including: The leakage detection circuit according to any one of claims 1-16.

19. The electrical device according to claim 18, characterized in that, The electrical equipment includes: a charging device.

20. A vehicle, characterized in that, Comprising: The electrical equipment according to claim 18.

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