Current detection circuit, leakage current detection method and charging system

Abstract

The present invention discloses a current detection circuit, a leakage current detection method and a charging system. The current detection circuit can output an excitation signal to a first winding in a magnetic induction coil, and then determine whether there is leakage current in a first conductor passing through the magnetic induction coil based on a feedback signal and a reference signal induced by the first winding. In other words, it can be determined whether there is leakage in the process of a charging device providing electric energy to the outside, and the determination result can be provided to a control circuit. When leakage occurs, the control circuit can promptly cut off the circuit of the charging device providing electric energy to the outside, so that the charging device stops providing electric energy to the outside, thereby reducing the occurrence of hazards and improving the safety and reliability of the charging process. At the same time, the reaction speed of the charging process control can be improved, and the timeliness can be improved. In addition, the application range of the current detection circuit is not limited by region and climate, which greatly broadens the application range of the current detection circuit.

Description

Technical Field

[0001] The present invention relates to the field of new energy technology, and in particular to a current detection circuit, a leakage current detection method and a charging system. Background Art

[0002] With the rapid development of the electric vehicle industry, people are paying more and more attention to the safety of electric vehicle charging products. Among them, the detection of leakage current during the charging process is an important requirement. By detecting the leakage current, it can be determined whether there is leakage current in the charging pile during the charging process of the electric vehicle. When leakage current exists, the connection between the charging pile and the electric vehicle can be cut off in time to avoid greater harm to the electric vehicle, the charging pile, and surrounding equipment or people, thereby improving the safety of the charging process.

[0003] Therefore, how to detect leakage current during the charging process is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0004] Embodiments of the present invention provide a current detection circuit, a leakage current detection method, and a charging system for detecting leakage current during a charging process.

[0005] In a first aspect, an embodiment of the present invention provides a current detection circuit, comprising an excitation module and a comparison module, wherein the excitation module is connected to a first winding wound in a magnetic induction coil, and a wire passes through the magnetic induction coil;

[0006] The excitation module is used to: output an excitation signal to the first winding;

[0007] The comparison module is used to determine whether there is leakage current in the wire according to the feedback signal induced by the first winding and a preset reference signal.

[0008] In this way, by setting up the current detection circuit, an excitation signal can be output to the first winding in the magnetic induction coil, and then based on the feedback signal and the reference signal induced by the first winding, it can be determined whether there is leakage current in the wire passing through the magnetic induction coil, which is conducive to the outside world to respond promptly and effectively according to the determination result, reduce the occurrence of hazards, and improve the safety and reliability of the charging process. At the same time, it can also improve the response speed of the charging process control and improve timeliness; in addition, the application scope of the current detection circuit is not limited by geography and climate, which greatly broadens the application scope of the current detection circuit.

[0009] Optionally, in this embodiment of the present invention, the comparison module is specifically configured to:

[0010] Determining whether the absolute value of the feedback signal is greater than the reference signal;

[0011] If so, determining that the leakage current exists in the wire;

[0012] If not, it is determined that the leakage current does not exist in the wire.

[0013] In this way, by comparing the relationship between the feedback signal and the reference signal, it is possible to quickly and effectively determine whether there is leakage current in the wire, thereby improving the detection efficiency of the leakage current.

[0014] Optionally, in an embodiment of the present invention, the excitation module includes: a signal generator;

[0015] The signal generator is used to generate the excitation signal.

[0016] In this way, the function of the excitation module can be effectively realized through the signal generator, thereby realizing the detection of leakage current in the wire.

[0017] Optionally, in an embodiment of the present invention, the excitation module includes a voltage dividing unit;

[0018] The voltage dividing unit is used to perform voltage dividing processing on the excitation signal before outputting the excitation signal to the first winding.

[0019] In this way, by voltage-dividing the excitation signal, the processed excitation signal can be effectively transmitted to both ends of the first winding, so as to facilitate subsequent detection of leakage current in the wire.

[0020] Optionally, in an embodiment of the present invention, the comparison module includes a comparison unit;

[0021] The comparison unit is used to: determine the effective signal and the interference signal in the feedback signal, amplify the effective signal to obtain a first signal; determine whether there is a leakage current in the wire based on the first signal and the reference signal; and output a second signal when it is determined that there is a leakage current in the wire.

[0022] In this way, by setting the comparison unit, the function of the comparison module can be realized, thereby realizing the detection of leakage current in the wire; at the same time, the accuracy of leakage current detection can be improved, the accuracy of the detection results can be improved, and an accurate and effective reference can be provided for subsequent processing.

[0023] Optionally, in an embodiment of the present invention, the comparison module further includes a first operational amplifier unit;

[0024] The first operational amplifier unit is configured to perform signal amplification processing on the feedback signal before determining the effective signal and the interference signal in the feedback signal.

[0025] In this way, the effective signal can be effectively extracted and the interference signal can be eliminated, so that the comparison unit can accurately and effectively determine whether there is leakage current in the wire, thereby improving the accuracy of the determination result.

[0026] Optionally, in an embodiment of the present invention, the comparison module further includes a second operational amplifier unit;

[0027] The second operational amplifier unit is used to perform power amplification processing on the second signal.

[0028] In this way, by amplifying the second signal (which can also be understood as power-level amplification), the external device can recognize the second signal when it receives the second signal, thereby facilitating the external device to make timely and effective processing and response, thereby improving the safety and reliability of the charging process.

[0029] Optionally, in an embodiment of the present invention, the current detection circuit further includes an auxiliary module;

[0030] The auxiliary module is connected to the second winding wound in the magnetic induction coil, and is used to:

[0031] During an initialization phase when no current flows through the wire, a preset current signal is output to the second winding to determine whether the excitation module and the comparison module can operate normally.

[0032] It should be noted that the first winding and the second winding wound in the magnetic induction coil are two different windings. When no current passes through the wire, a current signal can be input into the second winding; when the excitation module inputs the excitation signal into the first winding, the presence of the current in the second winding will change the magnetic field generated by the excitation signal. If the excitation module and the comparison module can determine that the feedback signal induced by the first winding is greater than the reference signal, it can be determined that the excitation module and the comparison module can work normally and effectively, thereby realizing self-inspection of the current detection circuit.

[0033] Optionally, in an embodiment of the present invention, the auxiliary module includes: a current generator.

[0034] In this way, the function of the auxiliary module can be realized through a simple structure, thereby realizing self-test of the current detection circuit.

[0035] In a second aspect, an embodiment of the present invention provides a charging system, comprising: a charging device, a magnetic induction coil, a switch, a control circuit, and a current detection circuit;

[0036] The current detection circuit is as described above in the embodiment of the present invention, and is connected to the magnetic induction coil and the control circuit respectively; the control circuit is connected to the charging device via a first wire, and the first wire passes through the magnetic induction coil;

[0037] The current detection circuit is used to: output an indication signal when it is determined that there is leakage current in the first conductive wire;

[0038] The control circuit is used to:

[0039] When the instruction signal is received, the charging device is controlled to stop providing electric energy to the outside; or, when the instruction signal is not received, the charging device is controlled to provide electric energy to the outside.

[0040] In this way, the control circuit can control whether the charging device provides electric energy to the outside according to whether the current detection circuit outputs an indication signal, so that when there is leakage current in the first wire passing through the magnetic induction coil, that is, when leakage occurs in the process of the charging device providing electric energy to the outside, the circuit for the charging device to provide electric energy to the outside is cut off in time, so that the charging device stops providing electric energy to the outside, thereby reducing the occurrence of hazards and improving the safety and reliability of the charging process.

[0041] Optionally, in an embodiment of the present invention, the first conducting wire includes a neutral wire and a live wire.

[0042] In this way, the electric energy provided by the charging device can be provided to the charged device, so that the charging device can charge the charged device.

[0043] In a third aspect, an embodiment of the present invention provides a leakage current detection method, comprising:

[0044] outputting an excitation signal to a first winding wound in the magnetic induction coil;

[0045] It is determined whether there is leakage current in the wire passing through the magnetic induction coil according to the feedback signal induced by the first winding and a preset reference signal.

[0046] In this way, by outputting an excitation signal to the first winding in the magnetic induction coil, and then determining whether there is leakage current in the wire passing through the magnetic induction coil based on the feedback signal and the reference signal induced by the first winding, the leakage situation can be promptly and effectively responded to based on the determination result, thereby reducing the occurrence of hazards and improving the safety and reliability of the charging process. At the same time, the response speed of the charging process control can also be improved, and the timeliness can be improved. In addition, the application scope of the current detection circuit is not limited by geography and climate, which greatly broadens the application scope of the current detection circuit.

[0047] The beneficial effects of the present invention are as follows:

[0048] An embodiment of the present invention provides a current detection circuit, a leakage current detection method, and a charging system. The current detection circuit can output an excitation signal to the first winding in the magnetic induction coil, and then determine whether there is a leakage current in the first wire passing through the magnetic induction coil based on the feedback signal and the reference signal induced by the first winding. In other words, it can be determined whether there is a leakage in the process of the charging device providing electric energy to the outside, and then the determination result is provided to the control circuit; when there is a leakage, the control circuit can promptly cut off the circuit for the charging device to provide electric energy to the outside, so that the charging device stops providing electric energy to the outside, thereby reducing the occurrence of hazards and improving the safety and reliability of the charging process; at the same time, it can also improve the response speed of the charging process control and improve timeliness; in addition, the application range of the current detection circuit is not limited by region and climate, which greatly broadens the application range of the current detection circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 A schematic structural diagram of a current detection circuit provided in an embodiment of the present invention;

[0050] Figure 2 A schematic structural diagram of another current detection circuit provided in an embodiment of the present invention;

[0051] Figure 3 This is a structural diagram of another current detection circuit provided in an embodiment of the present invention;

[0052] Figure 4 This is a structural diagram of another current detection circuit provided in an embodiment of the present invention;

[0053] Figure 5 This is a structural diagram of another current detection circuit provided in an embodiment of the present invention;

[0054] Figure 6 A schematic diagram of the specific structure of a reference voltage generator provided in an embodiment of the present invention;

[0055] Figure 7 This is a structural diagram of another current detection circuit provided in an embodiment of the present invention;

[0056] Figure 8 This is a structural diagram of another current detection circuit provided in an embodiment of the present invention;

[0057] Figure 9 A schematic diagram of the specific structure of a current generator provided in an embodiment of the present invention;

[0058] Figure 10 A schematic structural diagram of a charging system provided in an embodiment of the present invention;

[0059] Figure 11 A schematic structural diagram of a charging system provided in an embodiment of the present invention;

[0060] Figure 12 The present invention provides a flow chart of a leakage current detection method.

[0061] Among them, 10-magnetic induction coil, 20-current detection circuit, 21-excitation module, 21a-signal generating unit, 21b-signal processing unit, 22-comparison module, 22a-comparison unit, 22b-first operational amplifier unit, 22c-second operational amplifier unit, 22d-third operational amplifier unit, 23-reference voltage generator, 24-auxiliary module, 101-charging device, 102-charged device, 103-control circuit, 104-first wire, 105-second wire, L0-wire, B1-first comparator, B2-second comparator, B3-third comparator, Y1-first operational amplifier, Y2-second operational amplifier, Y3-third operational amplifier, Q1-driver, u1-first winding, u2-second winding. DETAILED DESCRIPTION

[0062] The following, in conjunction with the accompanying drawings, describes in detail the specific implementations of a current detection circuit, a leakage current detection method, and a charging system provided by an embodiment of the present invention. It should be noted that the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0063] The embodiment of the present invention provides a current detection circuit, such as Figure 1 As shown, it may include an excitation module 21 and a comparison module 22, wherein the excitation module 21 is connected to the first winding u1 wound in the magnetic induction coil 10, and a wire L0 passes through the magnetic induction coil 10;

[0064] The excitation module 21 is used to: output an excitation signal to the first winding u1;

[0065] The comparison module 22 is configured to determine whether there is leakage current in the wire L0 according to the feedback signal induced by the first winding u1 and a preset reference signal.

[0066] In this way, by setting up the current detection circuit, an excitation signal can be output to the first winding in the magnetic induction coil, and then based on the feedback signal and the reference signal induced by the first winding, it can be determined whether there is leakage current in the wire passing through the magnetic induction coil, which is conducive to the outside world to respond promptly and effectively according to the determination result, reduce the occurrence of hazards, and improve the safety and reliability of the charging process. At the same time, it can also improve the response speed of the charging process control and improve timeliness; in addition, the application scope of the current detection circuit is not limited by geography and climate, which greatly broadens the application scope of the current detection circuit.

[0067] It should be noted that, optionally, the detected leakage current can be an AC current or a DC current, that is, the above-mentioned current detection circuit provided in the embodiment of the present invention can detect both AC leakage current and DC leakage current, especially when detecting DC leakage current, the minimum DC leakage current that can be detected can reach 0.01mA, and the detection accuracy can reach ±0.01%. Not only does the above-mentioned current detection circuit provided in the embodiment of the present invention have a larger application range and meet the needs of different application scenarios, greatly improving the practicality of the current detection circuit, but it can also have faster and more accurate detection accuracy, and greatly improve the detection sensitivity.

[0068] Specifically, whether detecting DC leakage current or AC leakage current, during the detection process, the specific detection principles may include:

[0069] When an excitation signal is output to the first winding, the excitation signal can cause the magnetic induction coil to generate a magnetic field under the action of electromagnetic induction; when there is leakage current in the wire, the magnetic field generated by the excitation signal can change, and this change can cause an induced electromotive force to be generated at both ends of the first winding. When a loop is formed between the two ends of the first winding, an induced current can be generated;

[0070] The conductors may include a neutral wire and a live wire. If there is a difference between the current output from the live wire and the current input from the neutral wire, it can be considered that there is leakage current in the conductors.

[0071] At this time, an induced current (ie, a feedback signal) will exist in the excitation module connected to the first winding, and based on the relationship between the feedback signal and the reference signal, it can be determined whether there is leakage current in the wire.

[0072] Therefore, whether it is detecting DC leakage current or AC leakage current, the reference signal and excitation signal used in the detection process can be the same. Of course, they can also be adjusted and changed according to the form of the leakage current. As long as the leakage current can be detected, the specific implementation form of the reference signal and excitation signal can be set according to actual needs and is not limited here.

[0073] Furthermore, regardless of whether the DC leakage current or the AC leakage current is detected, the waveform of the feedback signal is determined by the form of the leakage current in the wire, so the implementation form of the feedback signal corresponds to the form of the leakage current in the wire.

[0074] In addition, the excitation signal can be a signal with adjustable frequency and amplitude, and the frequency and amplitude can be determined according to factors such as the specific setting structure of the current detection circuit and the detection accuracy, which are not limited here.

[0075] In addition, the waveform of the excitation signal can be set to, but not limited to, a square wave, and can also be set to other waveforms, such as a cosine wave, and can be set according to actual needs, which is not limited here.

[0076] Optionally, in this embodiment of the present invention, the comparison module is specifically configured to:

[0077] Determine whether the absolute value of the feedback signal is greater than the reference signal;

[0078] If so, it is determined that there is leakage current in the wire;

[0079] If not, it is determined that there is no leakage current in the wire.

[0080] The feedback signal may be a positive voltage value or a negative voltage value. Correspondingly, the reference voltage may be set to a positive voltage value to facilitate comparison between the absolute value of the feedback signal and the reference voltage.

[0081] In this way, by comparing the relationship between the feedback signal and the reference signal, it is possible to quickly and effectively determine whether there is leakage current in the wire, thereby improving the detection efficiency of the leakage current.

[0082] Optionally, in an embodiment of the present invention, Figure 2 As shown, the comparison module 22 includes a comparison unit 22a;

[0083] The comparison unit 22a is used to: determine the effective signal and the interference signal in the feedback signal (represented by Sk), amplify the effective signal to obtain a first signal (represented by Z1); determine whether there is a leakage current in the wire based on the first signal Z1 and the reference signal; and output a second signal (represented by Z2) when it is determined that there is a leakage current in the wire.

[0084] In this way, by setting the comparison unit, the function of the comparison module can be realized, thereby realizing the detection of leakage current in the wire; at the same time, the accuracy of leakage current detection can be improved, the accuracy of the detection results can be improved, and an accurate and effective reference can be provided for subsequent processing.

[0085] Optionally, in an embodiment of the present invention, Figure 3 As shown, the comparison module 22 further includes: a first operational amplifier unit 22b;

[0086] The first operational amplifier unit 22b is used to perform signal amplification processing on the feedback signal Sk before determining the effective signal and the interference signal in the feedback signal Sk.

[0087] In this way, the effective signal can be effectively extracted and the interference signal can be eliminated, so that the comparison unit can accurately and effectively determine whether there is leakage current in the wire, thereby improving the accuracy of the determination result.

[0088] Optionally, in an embodiment of the present invention, Figure 3 As shown, the comparison module 22 further includes: a second operational amplifier unit 22c;

[0089] The second operational amplifier unit 22c is configured to perform power amplification processing on the second signal Z2.

[0090] In this way, by amplifying the second signal (which can also be understood as power-level amplification), the external device can recognize the second signal when it receives the second signal, thereby facilitating the external device to make timely and effective processing and response, thereby improving the safety and reliability of the charging process.

[0091] Specifically, in the embodiment of the present invention, Figure 4 As shown, the comparison unit 22a includes: a first comparator B1, a second operational amplifier Y2, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8 and a ninth resistor R9, and a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4 and a fifth capacitor C5;

[0092] The first operational amplifier unit 22b may include: a first operational amplifier Y1, a first resistor R1, a second resistor R2 and a tenth resistor R10;

[0093] The second operational amplifier unit 22c may include: a third operational amplifier Y3, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a sixth capacitor C6;

[0094] The first input terminal of the first operational amplifier Y1 is respectively connected to the first end of the first resistor R1 and the excitation module 21, the second input terminal is respectively connected to the first end of the second resistor R2 and the excitation module 21, the third input terminal is connected to the power signal terminal VCC, the fourth input terminal is connected to the ground terminal GND, and the output terminal is respectively electrically connected to the second end of the first resistor R1 and the first end of the tenth resistor R10;

[0095] a second operational amplifier Y2 having a first input terminal connected to the first end of the third capacitor C3 and the first end of the ninth resistor R9, a second input terminal connected to the first end of the fourth capacitor C4 and the first end of the fifth capacitor C5, a third input terminal connected to the power signal terminal VCC, a fourth input terminal connected to the ground terminal GND, and an output terminal connected to the first end of the eighth resistor R8, the second end of the third capacitor C3, the first end of the sixth resistor R6, and the first end of the seventh resistor R7;

[0096] The first input terminal of the third operational amplifier Y3 is respectively connected to the first end of the first capacitor C1, the first end of the second capacitor C2, the second end of the fourth capacitor C4, and the second end of the fifth capacitor C5; the second input terminal is respectively connected to the first end of the third resistor R3, the first end of the fourth resistor R4, and the first end of the sixth capacitor C6; the third input terminal is connected to the power signal terminal VCC; the fourth input terminal is connected to the ground terminal GND; and the output terminal is respectively connected to the output terminal of the current detection circuit, the second end of the sixth capacitor C6, and the first end of the fifth resistor R5;

[0097] The first comparator B1 has a first input terminal connected to a reference voltage terminal S0 for providing a reference signal, a second input terminal connected to its output terminal, the second terminal of the second resistor R2, and the first terminal of the first capacitor C1, a third input terminal connected to a power signal terminal VCC, and a fourth input terminal connected to a ground terminal GND;

[0098] The second end of the third resistor R3, the second end of the fourth resistor R4, the second end of the fifth resistor R5, the second end of the sixth resistor R6 and the second end of the seventh resistor R7 are all connected to the second end of the first capacitor C1;

[0099] The second end of the eighth resistor R8 and the second end of the ninth resistor R9 are both connected to the second end of the tenth resistor R10.

[0100] In this way, through the coordinated use of the first operational amplifier, the first resistor, the second resistor and the tenth resistor, the function of the first operational amplifier unit can be realized, thereby realizing the first-stage amplification processing of the feedback signal; and, through the coordinated use of the sixth resistor, the seventh resistor, the eighth resistor and the ninth resistor, and the first capacitor, the second capacitor, the third capacitor, the fourth capacitor and the fifth capacitor, the interference signal in the first signal can be filtered out, leaving the effective signal, so that the second operational amplifier can perform the second-stage amplification processing on the effective signal; in addition, through the coordinated use of the third operational amplifier, the third resistor, the fourth resistor, the fifth resistor, and the sixth capacitor, the three-stage amplification processing of the third signal can be realized to realize the power-level signal amplification.

[0101] Optionally, in an embodiment of the present invention, the comparison module further includes: a seventh capacitor arranged between the power signal terminal and the ground terminal.

[0102] Among them, Figure 4 In the embodiment, the power signal terminal connected to the first operational amplifier, the second operational amplifier, the third operational amplifier and the first comparator can be the same terminal, and the ground terminal connected to the first operational amplifier, the second operational amplifier, the third operational amplifier and the first comparator can also be the same terminal. In this case, a seventh capacitor can be set between the power signal terminal and the ground terminal in the comparison module to further achieve signal filtering, thereby improving the accuracy of the output result of the comparison module.

[0103] It should be noted that, optionally, in the embodiment of the present invention, the specific structure of the comparison module is not limited to the above Figure 4 As shown, Figure 4 The structure shown is only a specific embodiment for realizing the function of the comparison module. The specific structure of the comparison module may also adopt other structures known to those skilled in the art that can realize the function of the comparison module, and is not limited here.

[0104] Optionally, in an embodiment of the present invention, Figure 5 As shown, the current detection circuit 20 may further include a reference voltage generator 23 , and the reference voltage generator 23 may be connected to the comparison unit 22 a to provide a reference voltage to the comparison unit 22 a .

[0105] The specific structure of the reference voltage generator can be as follows: Figure 6 As shown, it includes multiple capacitors (i.e. capacitors represented by X1 and X2), multiple resistors (i.e. resistors represented by F1 to F8) and a voltage regulator (i.e. Q1). The specific connection relationship can be seen in Figure 6 As shown, no further details are given here.

[0106] Of course, the specific structure of the reference voltage generator can also be other structures that can generate a reference voltage that are well known to those skilled in the art. It can be specifically set and selected according to actual needs and is not limited here.

[0107] In this way, by setting up the reference voltage generator, a reference voltage with higher precision and higher consistency can be provided to the comparison unit, so as to improve the accuracy of the leakage current detection results; at the same time, the reference voltage does not need to be applied and input externally, and can be generated by the reference voltage generator set by itself, thereby reducing dependence on external signals.

[0108] Optionally, in an embodiment of the present invention, Figure 2 As shown, the excitation module 21 includes: a signal generator 21a;

[0109] The signal generator 21a is used to generate the excitation signal.

[0110] In this way, the function of the excitation module can be effectively realized through the signal generator, thereby realizing the detection of leakage current in the wire.

[0111] Specifically, in the embodiment of the present invention, Figure 3 As shown, the excitation module 21 includes a voltage dividing unit; 21b;

[0112] The voltage dividing unit 21b is configured to perform voltage dividing processing on the excitation signal before outputting the excitation signal to the first winding.

[0113] In this way, by voltage-dividing the excitation signal, the processed excitation signal can be effectively transmitted to both ends of the first winding, so as to facilitate subsequent detection of leakage current in the wire.

[0114] Optionally, in an embodiment of the present invention, Figure 7 As shown, the signal generator 21a includes: a driver Q1, a second comparator B2, a third comparator B3, a thirteenth resistor R13, a nineteenth resistor R19, an eleventh resistor R11 and a fourteenth resistor R14;

[0115] The voltage dividing unit 21b includes: a twelfth resistor R12, a fifteenth resistor R15, a sixteenth resistor R16, a seventeenth resistor R17, an eighteenth resistor R18, a twentieth resistor R20 and a twenty-first resistor R21;

[0116] The first input terminal of the second comparator B2 is respectively connected to the first input terminal of the third comparator B3, the first end of the nineteenth resistor R19, and the first end of the seventeenth resistor R17; the second input terminal is respectively connected to the second input terminal of the third comparator B3, the first end of the thirteenth resistor R13, and the first end of the twelfth resistor R12; the third input terminal is connected to the power signal terminal VCC for providing a power signal; the fourth input terminal is connected to the ground terminal GND; and the output terminal is respectively connected to the first pin of the driver Q1 and the first end of the eleventh resistor R11;

[0117] The third comparator B3 has a third input terminal connected to the power signal terminal VCC, a fourth input terminal connected to the ground terminal GND, and an output terminal connected to the second pin of the driver Q1 and the first terminal of the fourteenth resistor R14 respectively;

[0118] The third pin of the driver Q1 is connected to the power signal terminal VCC, the fourth pin is connected to the ground terminal GND, the fifth pin is respectively connected to the first end d1 of the first winding u1 and the first end of the eighteenth resistor R18, and the sixth pin is respectively connected to the first end of the sixteenth resistor R16, the first end of the twentieth resistor R20, and the first end of the twenty-first resistor R21;

[0119] The second end of the thirteenth resistor R13 and the second end of the nineteenth resistor R19 are both connected to the ground terminal GND;

[0120] The second end of the eleventh resistor R11 and the second end of the fourteenth resistor R14 are both connected to the power signal terminal VCC;

[0121] The second end of the twelfth resistor R12 is respectively connected to the second end of the sixteenth resistor R16, the first end of the fifteenth resistor R15, and the second end d2 of the first winding u1;

[0122] A second end of the fifteenth resistor R15 is connected to the comparison module 21;

[0123] A second end of the eighteenth resistor R18 is connected to the second end of the twenty-first resistor R21 and the second end of the seventeenth resistor R17 respectively;

[0124] A second end of the twentieth resistor R20 is connected to the comparison module 21 .

[0125] In this way, through the cooperation between the above structures, an excitation signal can be generated, and voltage division processing of the excitation signal can be achieved, so as to excite the magnetic induction coil and facilitate the detection of leakage current.

[0126] Optionally, in an embodiment of the present invention, Figure 7 As shown, the excitation module 21 further includes: a first diode D1 to a fourth diode D4;

[0127] The anode of the first diode D1 and the cathode of the second diode D2 are both connected to the second end d2 of the first winding u1, the cathode of the first diode D1 is connected to the power signal terminal VCC, and the anode of the second diode D2 is connected to the ground terminal GND;

[0128] The anode of the third diode D3 and the cathode of the fourth diode D4 are both connected to the first end d1 of the first winding u1 , the cathode of the third diode D3 is connected to the power signal terminal VCC, and the anode of the fourth diode D4 is connected to the ground terminal GND.

[0129] In this way, by disposing a plurality of diodes, the signal processing unit can be protected due to the unidirectional conduction effect of the diodes, so as to ensure that the signal processing unit can transmit signals normally and effectively.

[0130] Optionally, in an embodiment of the present invention, the excitation module further includes: an eighth capacitor to an eleventh capacitor;

[0131] The eighth capacitor and the ninth capacitor are connected in parallel between the third pin of the driver and the fourth pin of the driver;

[0132] The first end of the tenth capacitor and the first end of the eleventh capacitor are connected to the third input terminal of the second comparator and the fourth input terminal of the second comparator respectively, and the second end of the tenth capacitor and the second end of the eleventh capacitor are connected between the third input terminal of the third comparator and the fourth input terminal of the third comparator respectively.

[0133] Among them, Figure 7 In the embodiment, the power signal terminal connected to the second comparator and the third comparator can be the same terminal, and the ground terminal connected to the second comparator and the third comparator can also be the same terminal. In this case, a tenth capacitor and an eleventh capacitor can be set in parallel between the power signal terminal and the ground terminal to further realize the signal filtering effect, thereby improving the accuracy of the output result of the signal generating unit.

[0134] It should be noted that, optionally, in the embodiment of the present invention, the specific structure of the excitation module is not limited to the above Figure 7 As shown, Figure 7 The structure shown is only a specific embodiment for realizing the function of the excitation module. The specific structure of the excitation module may also adopt other structures known to those skilled in the art that can realize the function of the excitation module, which is not limited here.

[0135] Optionally, in an embodiment of the present invention, Figure 8 As shown, the current detection circuit 20 further includes an auxiliary module 24;

[0136] The auxiliary module 24 is connected to the second winding u2 wound in the magnetic induction coil L0, and is used to:

[0137] During the initialization phase when no current flows through the wire L0 , a preset current signal is output to the second winding u2 to determine whether the excitation module 21 and the comparison module 22 can operate normally.

[0138] It should be noted that the first winding and the second winding wound in the magnetic induction coil are two different windings. When no current passes through the wire, a current signal can be input into the second winding to simulate the situation where there is leakage current in the wire passing through the magnetic induction coil; when the excitation module inputs the excitation signal into the first winding, the presence of current in the second winding will change the magnetic field generated by the excitation signal. If the excitation module and the comparison module can determine that the feedback signal induced by the first winding is greater than the reference signal, it can be determined that the excitation module and the comparison module can work normally and effectively, thereby realizing self-test of the current detection circuit.

[0139] Optionally, in an embodiment of the present invention, the auxiliary module includes: a current generator.

[0140] In this way, the function of the auxiliary module can be realized through a simple structure, thereby realizing self-test of the current detection circuit.

[0141] The structure of the current generator can be as follows: Figure 9 As shown, it includes multiple resistors (represented by F9 and F10), a transistor (represented by Q3) and a voltage regulator (represented by Q2). The specific connection relationship can be seen in Figure 9 As shown, no further details are given here.

[0142] Of course, the specific structure of the current generator can also be other structures that can generate current that are well known to those skilled in the art. It can be specifically set and selected according to actual needs and is not limited here.

[0143] The following combination Figure 7 The structural schematic diagram shown in FIG. 1 describes the working process of the current detection circuit provided by the embodiment of the present invention.

[0144] The second comparator B2 and the third comparator B3 operate in conjunction with the thirteenth resistor R13 and the nineteenth resistor R19, and input the generated signals to the first and second pins of the driver Q1, respectively. The pull-up effect of the eleventh resistor R11 provided at the first pin of the driver Q1 and the fourteenth resistor R14 provided at the second pin of the driver Q1 can improve the output capability of the driver Q1, thereby making the excitation signal output by the driver Q1 through the fifth and sixth pins (wherein the frequency and amplitude of the excitation signal can be adjusted according to actual needs) more accurate and effective;

[0145] Then, through the coordinated use of the twelfth resistor R12, the sixteenth resistor R16, the seventeenth resistor R17, the eighteenth resistor R18, and the twenty-first resistor R21, the excitation signal can be transmitted to the first winding u1, so that a magnetic field is generated in the magnetic induction coil;

[0146] When there is leakage current in the wire passing through the magnetic induction coil, the presence of the leakage current will cause the magnetic field to change, thereby causing the first winding u1 to output a feedback signal;

[0147] Among them, since the first diode D1 to the fourth diode D4 have a unidirectional conduction function, they can protect the excitation module and avoid the influence of the feedback signal on the excitation module;

[0148] Furthermore, the feedback signal may first pass through the fifteenth resistor R15, the sixteenth resistor R16, the eighteenth resistor R18, the twentieth resistor R20, and the twenty-first resistor R21, and then be transmitted to the first input terminal and the second input terminal of the first operational amplifier Y1 after voltage division processing by these resistors;

[0149] The first operational amplifier Y1 amplifies the feedback signal in cooperation with the first resistor R1 and the tenth resistor R10, and then transmits the amplified feedback signal to the comparison unit 22a;

[0150] In the comparison unit 22a, filtering processing can be performed through the action of the first capacitor C1 to the fifth capacitor C5 to extract effective information from the amplified feedback signal. The extracted effective information is then amplified through the cooperation of the eighth resistor R8, the ninth resistor R9, and the second operational amplifier Y2. After that, the obtained first signal Z1 is transmitted to the first comparator B1 through the output action of the sixth resistor R6 and the seventh resistor R7. The first comparator B1 can follow and compare the reference voltage, and the second signal Z2 outputted by it is transmitted to the third operational amplifier Y3.

[0151] The third operational amplifier Y3, the third resistor R3 to the fifth resistor R5, and the sixth capacitor C6 cooperate to amplify the output of the indication signal K0 (for example, but not limited to, a high-level signal) to inform external devices of the presence of leakage current in the wire, thereby guiding the external devices to respond promptly and effectively, thereby improving the safety and reliability of the charging process.

[0152] It should be emphasized that since the above-mentioned current detection circuit provided in the embodiment of the present invention is composed of simple components, it can help reduce the manufacturing cost of the current detection circuit; at the same time, the above-mentioned current detection circuit occupies a small area as a whole, making the overall size of the current detection circuit small, convenient for installation and use in various charging systems, greatly improving the practicality of the current detection circuit.

[0153] Moreover, according to the waveform of the current signal, the current types of leakage current mainly include: sinusoidal current signals, current signals containing pulsating DC components, and current signals containing smooth DC components. The above-mentioned current detection circuit provided in the embodiment of the present invention can detect the above-mentioned three types of leakage currents, so that in actual use, it will not be restricted by the type of leakage current to be detected, thereby making the above-mentioned current detection circuit provided in the embodiment of the present invention have a wide range of uses.

[0154] Based on the same inventive concept, an embodiment of the present invention provides a charging system, such as Figure 10 As shown, it may include: a charging device 101, a magnetic induction coil 10, a control circuit 103, and a current detection circuit 20;

[0155] The current detection circuit 20 is the current detection circuit described above in the embodiment of the present invention, and is connected to the magnetic induction coil 10 and the control circuit 103 respectively. The control circuit 103 is connected to the charging device 101 via a first wire 104, which passes through the magnetic induction coil 10.

[0156] The current detection circuit 20 is used to: output an indication signal K0 when it is determined that there is leakage current in the first conductive line 104;

[0157] The control circuit is used to:

[0158] When the instruction signal K0 is received, the charging device 101 is controlled to stop providing electric energy to the outside; or, when the instruction signal K0 is not received, the charging device 101 is controlled to provide electric energy to the outside.

[0159] In this way, the control circuit can control whether the charging device provides electric energy to the outside according to whether the current detection circuit outputs an indication signal, so that when there is leakage current in the first wire passing through the magnetic induction coil, that is, when leakage occurs in the process of the charging device providing electric energy to the outside, the circuit for the charging device to provide electric energy to the outside is cut off in time, so that the charging device stops providing electric energy to the outside, thereby reducing the occurrence of hazards and improving the safety and reliability of the charging process.

[0160] Moreover, when the control circuit cuts off the circuit through which the charging device supplies power to the outside, the response speed can reach the ms level, and the fastest speed is within 0.01ms, thereby greatly improving the control of the charging system and greatly improving the safety and reliability of the charging process.

[0161] Optionally, in an embodiment of the present invention, Figure 10 As shown, the first conductive wire may include a neutral wire and a live wire, and the neutral wire and the live wire may pass through the magnetic induction coil 10 .

[0162] Specifically, in the embodiment of the present invention, Figure 11 As shown, the control circuit 103 can be connected to the charged device 102 via a second wire 105 . Correspondingly, the second wire 105 can also include a neutral wire and a live wire.

[0163] Optionally, in an embodiment of the present invention, Figure 11 As shown, the control circuit 103 may include: a controller 103b and a switch 103a. The switch 103a may be provided between the charging device 101 and the charged device 102. The controller 103b is connected to the switch 103a and the current detection circuit 20 respectively.

[0164] That is: the switch is set on the neutral wire and the live wire paper, but the controller is not set on the neutral wire and the live wire paper;

[0165] When the controller receives an indication signal, it can control the switch to open to switch the connection between the charging device and the charged device and stop the charging process; or, when the controller does not receive an indication signal, it can control the switch to close to maintain the connection between the charging device and the charged device and keep the charging process running normally.

[0166] Furthermore, at least one switch may be provided in the charging system;

[0167] When the switch is provided with one, it can be set on the neutral line or on the live line;

[0168] Alternatively, when two switches are provided, one switch may be provided on the neutral line, and the other switch may be provided on the live line.

[0169] Specifically, in the embodiment of the present invention, the switch may be, but is not limited to, a relay, and may also be other structures known to those skilled in the art that can realize a switch function, which is not limited here.

[0170] Optionally, in an embodiment of the present invention, the connection between the first winding and the current detection circuit may include:

[0171] Method 1: Leads are provided at both ends of the first winding, and the current detection circuit can be connected to the first winding through the lead wires;

[0172] Method 2: Welding points are provided at both ends of the first winding, and the current detection circuit can be connected to the welding points by welding to achieve connection with the first winding.

[0173] In actual situations, one of the above methods 1 and 2 can be selected to realize the connection between the first winding and the current detection circuit according to the actual situation, so as to meet the needs of different application scenarios and improve the flexibility of design.

[0174] Based on the same inventive concept, an embodiment of the present invention provides a leakage current detection method. The implementation principle of this detection method is similar to the implementation principle of the aforementioned current detection circuit. The specific implementation method of this detection method can refer to the specific embodiment of the aforementioned current detection circuit, and the repeated parts will not be repeated.

[0175] Specifically, the above leakage current detection method provided by the embodiment of the present invention is as follows: Figure 12 As shown, this may include:

[0176] S1201, outputting an excitation signal to a first winding wound in a magnetic induction coil;

[0177] S1202: Determine whether there is leakage current in the wire passing through the magnetic induction coil based on the feedback signal induced by the first winding and a preset reference signal.

[0178] In this way, by outputting an excitation signal to the first winding in the magnetic induction coil, and then determining whether there is leakage current in the wire passing through the magnetic induction coil based on the feedback signal and the reference signal induced by the first winding, the leakage situation can be promptly and effectively responded to based on the determination result, thereby reducing the occurrence of hazards and improving the safety and reliability of the charging process. At the same time, the response speed of the charging process control can also be improved, and the timeliness can be improved. In addition, the application scope of the current detection circuit is not limited by geography and climate, which greatly broadens the application scope of the current detection circuit.

[0179] Optionally, in an embodiment of the present invention, determining whether there is leakage current in the wire passing through the magnetic induction coil according to the feedback signal and the preset reference signal includes:

[0180] Determine whether the absolute value of the feedback signal is greater than the reference signal;

[0181] If so, it is determined that there is leakage current in the wire;

[0182] If not, it is determined that there is no leakage current in the wire.

[0183] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A current detection circuit, characterized in that: The device comprises an excitation module and a comparison module, wherein the excitation module is connected to a first winding wound in a magnetic induction coil, and a wire passes through the magnetic induction coil; The excitation module is used to: output an excitation signal to the first winding; The comparison module is used to determine whether there is leakage current in the wire according to the feedback signal induced by the first winding and a preset reference signal; The comparison module includes a comparison unit; the comparison unit is configured to: determine a valid signal and an interference signal in the feedback signal, amplify the valid signal to obtain a first signal; determine whether there is a leakage current in the wire based on the first signal and the reference signal; and output a second signal when it is determined that there is a leakage current in the wire; The comparison unit includes: a first comparator, a second operational amplifier, a sixth resistor, a seventh resistor, an eighth resistor and a ninth resistor, and a first capacitor, a second capacitor, a third capacitor, a fourth capacitor and a fifth capacitor; A first input terminal of the first comparator is connected to a reference voltage terminal for providing the reference signal, a second input terminal of the first comparator is respectively connected to its output terminal, the first output terminal of the excitation module, the first terminal of the first capacitor, the first terminal of the second capacitor, the second terminal of the fourth capacitor, and the second terminal of the fifth capacitor, a third input terminal of the first comparator is connected to a power signal terminal, and a fourth input terminal of the first comparator is connected to a ground terminal; The second end of the first capacitor is connected to the second end of the second capacitor, the second end of the sixth resistor, and the second end of the seventh resistor respectively; a first input terminal of the second operational amplifier connected to the first end of the third capacitor and the first end of the ninth resistor, respectively; a second input terminal of the second operational amplifier connected to the first end of the fourth capacitor and the first end of the fifth capacitor, respectively; a third input terminal of the second operational amplifier connected to the power signal terminal; a fourth input terminal of the second operational amplifier connected to the ground terminal; and an output terminal of the second operational amplifier connected to the first end of the eighth resistor, the second end of the third capacitor, the first end of the sixth resistor, and the first end of the seventh resistor, respectively; The second end of the eighth resistor and the second end of the ninth resistor are both connected to the second output end of the excitation module.

2. The current detection circuit according to claim 1, wherein: The comparison module is specifically used for: Determining whether the absolute value of the feedback signal is greater than the reference signal; If so, determining that the leakage current exists in the wire; If not, it is determined that the leakage current does not exist in the wire.

3. The current detection circuit according to claim 1, wherein: The excitation module includes: a signal generator; The signal generator is used to generate the excitation signal.

4. The current detection circuit according to claim 1, wherein: The excitation module includes a voltage dividing unit; The voltage dividing unit is used to perform voltage dividing processing on the excitation signal before outputting the excitation signal to the first winding.

5. The current detection circuit according to claim 1, wherein: The comparison module also includes a first operational amplifier unit; The first operational amplifier unit is configured to perform signal amplification processing on the feedback signal before determining the effective signal and the interference signal in the feedback signal.

6. The current detection circuit according to claim 1, wherein: The comparison module also includes a second operational amplifier unit; The second operational amplifier unit is used to perform power amplification processing on the second signal.

7. The current detection circuit according to claim 1, wherein: The current detection circuit also includes an auxiliary module; The auxiliary module is connected to the second winding wound in the magnetic induction coil, and is used to: During an initialization phase when no current flows through the wire, a preset current signal is output to the second winding to determine whether the excitation module and the comparison module can operate normally.

8. The current detection circuit according to claim 7, wherein: The auxiliary module includes: a current generator.

9. A charging system, characterized in that: include: Charging device, magnetic induction coil, control circuit, and current detection circuit; The current detection circuit is as described in any one of claims 1 to 8, and the current detection circuit is connected to the magnetic induction coil and the control circuit respectively; the control circuit is connected to the charging device via a first wire, and the first wire passes through the magnetic induction coil; The current detection circuit is used to: output an indication signal when it is determined that there is leakage current in the first conductive wire; The control circuit is used to: When the instruction signal is received, the charging device is controlled to stop providing electric energy to the outside; or, when the instruction signal is not received, the charging device is controlled to provide electric energy to the outside.

10. The charging system according to claim 9, wherein: The first conducting wire includes a neutral wire and a live wire.

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