Current detection circuit, leakage current detection method, and charging system

Abstract

The present invention discloses a current detection circuit (20), a leakage current detection method, and a charging system, in which the current detection circuit (20) outputs an excitation signal to a first winding (ul) of an electromagnetic induction coil (10), and determines whether a leakage current exists in a first wire (L0) passing through the electromagnetic induction coil (10) based on a feedback signal and a reference signal induced in the first winding (ul), i.e., determines whether a leakage condition exists during the process of the charging device (101) supplying electrical energy to the outside, and provides the determination result to a control circuit (103). If a leakage condition exists, the control circuit (103) immediately disconnects the circuit through which the charging device (101) supplies electrical energy to the outside, so that the charging device (101) stops supplying electrical energy to the outside, thereby reducing the occurrence of hazards and improving the safety and reliability of the charging process, as well as improving the response speed and aging resistance of the charging process control. Furthermore, the range of application of the current detection circuit (20) is not limited by region or climate, which significantly widens the range of application of the current detection circuit (20).

Description

[Technical field]

[0001] This application claims priority to a Chinese patent application filed on November 17, 2020, bearing application number 202011289085.1 and entitled "Current Detection Circuit, Leakage Current Detection Method and Charging System," the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to the technical field of new energy, and in particular to a current detection circuit, a leakage current detection method, and a charging system. [Background technology]

[0003] With the rapid development of the electric vehicle field, people attach more and more importance to the safety of electric vehicle charging products, in which the detection of leakage current during the charging process is an important requirement, and the detection of leakage current can determine whether there is leakage current during the charging process of the electric vehicle by the charging station. If leakage current is detected, the connection between the charging station and the electric vehicle can be immediately cut off, thereby avoiding serious harm to the electric vehicle, the charging station, and surrounding equipment and people, and improving the safety of the charging process.

[0004] However, how to detect leakage current during the charging process is a technical problem that must be urgently solved by those skilled in the art. Summary of the Invention

[0005] SUMMARY OF THE DISCLOSURE The 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.

[0006] In a first aspect, an embodiment of the present invention provides a current sensing circuit, comprising: The present invention includes an excitation module and a comparison module, the excitation module being connected to a first winding of an electromagnetic induction coil, a wire passing through the electromagnetic induction coil; the excitation module outputs an excitation signal to the first winding; The comparison module provides a current detection circuit that determines whether there is a leakage current in the wire based on a feedback signal induced in the first winding and a preset reference signal.

[0007] In a second aspect, an embodiment of the present invention provides a charging system, comprising: a charging device, an electromagnetic induction coil, a switch, a control circuit, and a current sensing circuit, such as the current sensing circuit according to an embodiment of the present invention; the current detection circuit is connected to the electromagnetic induction coil and the control circuit, the control circuit is connected to the charging device via a first wire, the first wire passes through the electromagnetic induction coil; the current detection circuit outputs an indication signal when it is determined that a leakage current exists in the first wire; The control circuit provides a charging system in which, when the instruction signal is received, the control circuit controls the charging device to stop supplying electrical energy to the outside, or, when the instruction signal is not received, controls the charging device to supply electrical energy to the outside.

[0008] In this way, the control circuit controls whether the charging equipment supplies electrical energy to the outside based on whether the current detection circuit outputs an indication signal, so that if there is a leakage current in the first wire passing through the electromagnetic induction coil, i.e., if a leakage situation occurs during the process of the charging equipment supplying electrical energy to the outside, the control circuit immediately disconnects the circuit through which the charging equipment supplies electrical energy to the outside, thereby causing the charging equipment to stop supplying electrical energy to the outside, thereby reducing the occurrence of harm and improving the safety and reliability of the charging process.

[0009] In a third aspect, an embodiment of the present invention provides a leakage current detection method, comprising: outputting an excitation signal to a first winding of an electromagnetic induction coil; determining whether a leakage current exists in a wire passing through the electromagnetic induction coil based on a feedback signal induced in the first winding and a preset reference signal; The present invention provides a leakage current detection method, comprising:

[0010] The current detection circuit, leakage current detection method, and charging system according to the embodiments of the present invention can be installed in a current detection circuit to output an excitation signal to a first winding in an electromagnetic induction coil, and can determine whether there is a leakage current in a first wire passing through the electromagnetic induction coil based on a feedback signal and a reference signal induced in the first winding, that is, can determine whether there is a leakage situation during the process of the charging equipment supplying electrical energy to the outside, and can supply the determination result to a control circuit. If there is a leakage situation, the control circuit can immediately disconnect the circuit through which the charging equipment supplies electrical energy to the outside, so that the charging equipment stops supplying electrical energy to the outside, thereby reducing the occurrence of harm and improving the safety and reliability of the charging process, as well as improving the response speed to control of the charging process and improving the aging resistance. In addition, the application range of the current detection circuit is not limited by region or climate, and greatly expands the application range of the current detection circuit. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a structural schematic diagram of a current detection circuit according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a structural schematic diagram of another current detection circuit according to an embodiment of the present invention. [Diagram 3] FIG. 3 is a structural schematic diagram of yet another current detection circuit according to an embodiment of the present invention. [Figure 4] FIG. 4 is a structural schematic diagram of yet another current detection circuit according to an embodiment of the present invention. [Diagram 5] FIG. 5 is a structural schematic diagram of yet another current detection circuit according to an embodiment of the present invention. [Figure 6] FIG. 6 is a detailed structural schematic diagram of a reference voltage generator according to an embodiment of the present invention. [Figure 7] FIG. 7 is a structural schematic diagram of yet another current detection circuit according to an embodiment of the present invention. [Figure 8] FIG. 8 is a structural schematic diagram of yet another current detection circuit according to an embodiment of the present invention. [Figure 9] FIG. 9 is a detailed structural schematic diagram of a current generator according to an embodiment of the present invention. [Figure 10] FIG. 10 is a structural schematic diagram of a charging system according to an embodiment of the present invention. [Figure 11] FIG. 11 is a structural schematic diagram of a charging system according to an embodiment of the present invention. [Figure 12] FIG. 12 is a flow chart of a leakage current detection method according to an embodiment of the present invention. [Explanation of symbols]

[0012] 10- Electromagnetic induction coil, 20-Current detection circuit, 21-Excitation module, 21a - signal generator, 21b-Divider unit, 22-Compare module, 22a-Comparative units, 22b - first operational amplifier unit; 22c - second operational amplifier unit, 23- Reference voltage generator, 24-Auxiliary module, 101-Charging equipment, 102-Charged equipment, 103 - control circuit, 104 - first wire, 105 - second wire, L0-wire, B1 - first comparator, B2 - second comparator, B3 - third comparator, Y1 - the first operational amplifier, Y2 - second operational amplifier, Y3 - third operational amplifier, Q1 - Drive, u1 - first winding, u2 - second winding. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, specific embodiments of a current detection circuit, a leakage current detection method, and a charging system according to the present invention will be described in detail with reference to the drawings. Note that the described embodiments are only some of the embodiments of the present invention, and are not all of the embodiments. All other embodiments obtained by those skilled in the art without any creative effort based on the embodiments of the present invention are within the scope of protection of the present invention.

[0014] An embodiment of the present invention provides a current detection circuit, as shown in FIG. 1, the current detection circuit 20 includes an excitation module 21 and a comparison module 22, the excitation module 21 is connected to a first winding u1 of an electromagnetic induction coil 10, a wire L0 is passed through the electromagnetic induction coil 10, and the comparison module 22 is connected to the excitation module 21; The excitation module 21 outputs an excitation signal to the first winding u1 and receives a feedback signal induced in the first winding u1; The comparison module 22 determines whether there is a leakage current in the wire L0 based on the feedback signal induced in the first winding u1 and a preset reference signal.

[0015] In this way, by installing it in a current detection circuit, an excitation signal is output to the first winding in the electromagnetic induction coil, and then based on the feedback signal and reference signal induced in the first winding, it is determined whether there is a leakage current in the wire passing through the electromagnetic induction coil, and further, it contributes to an immediate and effective external response based on the determination result, reduces the occurrence of harm, improves the safety and reliability of the charging process, and can also improve the response speed to the control of the charging process and improve the aging resistance. Furthermore, the application range of the current detection circuit is not limited by region or climate, and greatly expands the application range of the current detection circuit.

[0016] In addition, optionally, the leakage current to be detected may be an AC current or a DC current, that is, the above current detection circuit according to the embodiment of the present invention can realize detection of both AC leakage current and DC leakage current. In particular, when detecting DC leakage current, the minimum detectable DC leakage current can reach 0.01 mA, and the detection accuracy can reach ±0.01%. The above current detection circuit according to the embodiment of the present invention has a wide application range and meets the requirements of different application scenarios, and can not only greatly improve the practicability of the current detection circuit, but also has faster and more accurate detection accuracy and greatly improves the detection sensitivity.

[0017] Specifically, whether detecting DC leakage current or AC leakage current, the specific detection principle during the detection process is as follows: When an excitation signal is output to the first winding, the excitation signal can generate a magnetic field in the electromagnetic induction coil through the effect of electromagnetic induction; when there is a leakage current in the wire, the excitation signal can cause a change in the magnetic field, and such a change can generate an induced electromotive force at both ends of the first winding; and when a circuit is formed at both ends of the first winding, an induced current can be generated; Here, the wires may include neutral and live wires, and 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 a leakage current in the wire.

[0018] At that time, an induced current (i.e., a feedback signal) exists 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 a leakage current in the wire.

[0019] Therefore, whether DC leakage current or AC leakage current is detected, the reference signal and excitation signal used during the detection process may be the same, and may of course be adjusted and modified according to the type of leakage current. As long as the leakage current can be detected, the specific implementation of the reference signal and excitation signal may be set according to actual needs, and is not limited here.

[0020] Furthermore, whether a DC leakage current or an 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.

[0021] Furthermore, the excitation signal may be a signal whose frequency and amplitude are adjustable, and the magnitude of the frequency and amplitude may be determined according to factors such as the specific installation structure and detection accuracy of the current detection circuit, and are not limited here.

[0022] In addition, the waveform of the excitation signal may be set to a square wave, but is not limited thereto, and may be set to other waveforms, such as a cosine wave, or may be set according to actual needs, and is not limited here.

[0023] Optionally, in an embodiment of the present invention, the comparison module specifically comprises: determining whether the absolute value of the feedback signal is greater than the reference signal; If it is large, it is determined that there is a leakage current in the wire. If it is not, it is determined that there is no leakage current in the wire.

[0024] Here, the feedback signal may be a positive voltage value or a negative voltage value, and correspondingly, the reference voltage may be set to a positive voltage value to compare with the absolute value of the feedback signal.

[0025] In this manner, 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 efficiency of leakage current detection.

[0026] Optionally, in an embodiment of the present invention, as shown in FIG. 2, the comparison module 22 includes a comparison unit 22a: The comparison unit 22a determines an effective signal and an interference signal in a feedback signal (denoted by Sk), amplifies the effective signal to obtain a first signal (denoted by Z1), and determines whether there is a leakage current in the wire based on the first signal Z1 and the reference signal, and outputs a second signal Z2 when it is determined that there is a leakage current in the wire.

[0027] In this way, by installing the comparison unit, the function of the comparison module can be realized, so as to realize detection of leakage current in the wire, and also to improve the accuracy of leakage current detection, improve the accuracy of the detection result, and provide an accurate and effective reference for subsequent processing.

[0028] Optionally, in an embodiment of the present invention, as shown in FIG. 3, the comparison module 22 further includes a first operational amplification unit 22b, one end of which is connected to the comparison unit 22a and the other end of which is connected to the excitation module 21; The first operational amplifier unit 22b performs signal amplification processing on the feedback signal Sk before identifying useful and interfering signals in the feedback signal Sk.

[0029] In this way, the useful signal can be effectively extracted and the interference signal can be filtered out, so that the comparison unit can accurately and effectively determine whether there is leakage current in the wire, and improve the accuracy of the determination result.

[0030] Optionally, in an embodiment of the present invention, as shown in FIG. 3, the comparison module 22 further includes a second operational amplification unit 22c, one end of which is connected to the comparison unit 22a and the other end of which constitutes an output end of the comparison module 22; The second operational amplifier unit 22c performs power amplification processing on the second signal Z2.

[0031] In this way, amplifying the second signal (which may be understood as amplifying the power level) can contribute to the external device's identification of the second signal when it receives the second signal, thereby contributing to improved instantaneous and effective processing and response of the external device, and improving the safety and reliability of the charging process.

[0032] Specifically, in the embodiment of the present invention, as shown in FIG. 4, 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, a ninth resistor R9, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4 and a fifth capacitor C5; 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; 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; Here, the first input terminal of the first operational amplifier Y1 is respectively connected to the first terminal of the first resistor R1 and the excitation module 21, the second input terminal is respectively connected to the first terminal 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 terminal of the first resistor R1 and the first terminal of the tenth resistor R10; The first input terminal of the second operational amplifier Y2 is connected to the first terminal of the third capacitor C3 and the first terminal of the ninth resistor R9, the second input terminal is connected to the first terminal of the fourth capacitor C4 and the first terminal of the fifth capacitor C5, 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 connected to the first terminal of the eighth resistor R8, the second terminal of the third capacitor C3, the first terminal of the sixth resistor R6 and the first terminal of the seventh resistor R7, The first input terminal of the third operational amplifier Y3 is connected to the first terminal of the first capacitor C1, the first terminal of the second capacitor C2, the second terminal of the fourth capacitor C4, and the second terminal of the fifth capacitor C5, the second input terminal is connected to the first terminal of the third resistor R3, the first terminal of the fourth resistor R4, and the first terminal 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 connected to the output terminal of the current detection circuit, the second terminal of the sixth capacitor C6, and the first terminal of the fifth resistor R5, The first input terminal of the first comparator B1 is connected to a reference voltage terminal S0 for providing a reference signal, the second input terminal is connected to its output terminal, the second terminal of the second resistor R2 and the first terminal of the first capacitor C1 respectively, the third input terminal is connected to a power signal terminal VCC, and the fourth input terminal is connected to a ground terminal GND; a second terminal of the third resistor R3, a second terminal of the fourth resistor R4, a second terminal of the fifth resistor R5, a second terminal of the sixth resistor R6, and a second terminal of the seventh resistor R7 are all connected to a second terminal of the first capacitor C1; A second terminal of the eighth resistor R8 and a second terminal of the ninth resistor R9 are both connected to a second terminal of the tenth resistor R10.

[0033] In this way, the combination of the first operational amplifier, the first resistor, the second resistor, and the tenth resistor can realize the function of the first operational amplification unit, and can further realize a single-stage amplification process for the feedback signal; the combination of the sixth resistor, the seventh resistor, the eighth resistor, the ninth resistor, the first capacitor, the second capacitor, the third capacitor, the fourth capacitor, and the fifth capacitor can filter out the interference signal in the first signal and leave the useful signal, so that the second operational amplifier performs two-stage amplification process for the useful signal; the combination of the third operational amplifier, the third resistor, the fourth resistor, the fifth resistor, and the sixth capacitor can realize a three-stage amplification process for the third signal, and can realize signal amplification of the power level.

[0034] Optionally, in an embodiment of the present invention, the comparison module further includes a seventh capacitor disposed between the power signal terminal and the ground terminal.

[0035] Here, in FIG. 4, the power signal terminal connected to the first operational amplifier, the second operational amplifier, the third operational amplifier and the first comparator may be the same terminal, and similarly, the ground terminal connected to the first operational amplifier, the second operational amplifier, the third operational amplifier and the first comparator may be the same terminal. In this case, a seventh capacitor may be provided between the power signal terminal and the ground terminal of the comparison module to further realize the signal filtering function, thereby improving the accuracy of the output result of the comparison module.

[0036] In addition, optionally, in the embodiments of the present invention, the specific structure of the comparison module is not limited to that shown in FIG. 4 above. That is, the structure shown in FIG. 4 is merely one specific embodiment for realizing the function of the comparison module. The specific structure of the comparison module may also adopt other structures capable of realizing the function of the comparison module known to those skilled in the art, and is not limited here.

[0037] Optionally, in an embodiment of the present invention, as shown in FIG. 5, 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 22a to provide a reference voltage Vref to the comparison unit 22a.

[0038] Here, the specific structure of the reference voltage generator 23 is as shown in FIG. 6, that is, it may include a plurality of capacitors (i.e., the capacitors indicated by X1 and X2), a plurality of resistors (i.e., the resistors indicated by F1 to F8) and one constant voltage diode (i.e., Q1), and the specific connection relationship is as shown in FIG. 6, and will not be described in further detail here.

[0039] Of course, the specific structure of the reference voltage generator may also be other structures capable of generating a reference voltage known to those skilled in the art, and may be specifically installed and selected according to actual needs, and is not limited herein.

[0040] In this way, by installing a reference voltage generator, a highly accurate and consistent reference voltage can be supplied to the comparison unit, which contributes to improving the accuracy of the leakage current detection results, and the reference voltage can be generated by the reference voltage generator installed in the comparison unit itself without requiring external application or input, thereby reducing dependency on external signals.

[0041] Optionally, in an embodiment of the present invention, as shown in FIG. 2, the excitation module 21 includes a signal generator 21a; The signal generator 21a generates the excitation signal.

[0042] In this way, the signal generator effectively performs the function of an excitation module, thereby providing detection for leakage currents in the wires.

[0043] Specifically, in an embodiment of the present invention, as shown in FIG. 3, the excitation module 21 further includes a voltage divider unit 21b, one end of which is connected to the signal generator 21a and the other end of which is connected to the first winding u1; The voltage dividing unit 21b divides the excitation signal before outputting the excitation signal to the first winding.

[0044] In this manner, a voltage divider process on the excitation signal effectively transmits a processed excitation signal across the first winding for subsequent detection of leakage current in the wire.

[0045] Optionally, in an embodiment of the present invention, as shown in FIG. 7, 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; 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, Here, the second comparator B2 has a first input terminal connected to the first input terminal of the third comparator B3, a first terminal of the 19th resistor R19, and a first terminal of the 17th resistor R17, a second input terminal connected to the second input terminal of the third comparator B3, a first terminal of the 13th resistor R13, and a first terminal of the 12th resistor R12, a third input terminal connected to a power signal terminal VCC for supplying a power signal, a fourth input terminal connected to the ground terminal GND, and an output terminal connected to the first pin of the drive Q1 and the first terminal of the 11th resistor R11, 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; The driver Q1 has a third pin connected to the power supply signal terminal VCC, a fourth pin connected to the ground terminal GND, a fifth pin connected to the first end d1 of the first winding u1 and the first end of the eighteenth resistor R18, and a sixth pin 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, The second terminal of the thirteenth resistor R13 and the second terminal of the nineteenth resistor R19 are both connected to the ground terminal GND; 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; A second end of the twelfth resistor R12 is connected to a second end of the sixteenth resistor R16, a first end of the fifteenth resistor R15, and a second end d2 of the first winding u1, respectively; The second end of the fifteenth resistor R15 is connected to the comparison module 21; A second terminal of the resistor R18 is connected to a second terminal of the resistor R21 and a second terminal of the resistor R17, The second end of the twentieth resistor R20 is connected to the comparison module 21.

[0046] In this way, by the cooperative operation between the above-mentioned structures, an excitation signal can be generated, and excitation of the electromagnetic induction coil can be realized, and voltage division processing of the excitation signal can also be realized so as to contribute to the detection of leakage current.

[0047] Optionally, in an embodiment of the present invention, as shown in FIG. 7, the excitation module 21 further includes a first diode D1 to a fourth diode D4; 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 end VCC, and the anode of the second diode D2 is connected to the ground end GND; 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 supply signal end VCC, and the anode of the fourth diode D4 is connected to the ground end GND.

[0048] In this way, by installing a number of diodes, the signal processing unit can be protected by the unidirectional conduction of the diodes to ensure that the signal processing unit can transmit signals normally and effectively.

[0049] Optionally, in an embodiment of the present invention, the excitation module further includes an eighth capacitor to an eleventh capacitor; an eighth capacitor and a ninth capacitor are connected in parallel between the third pin of the drive and the fourth pin of the drive; The first end of the tenth capacitor and the first end of the eleventh capacitor are connected to the third input end of the second comparator and the fourth input end of the second comparator, respectively, and the second end of the tenth capacitor and the second end of the eleventh capacitor are connected to the third input end of the third comparator and the fourth input end of the third comparator, respectively.

[0050] Here, in FIG. 7, the power signal terminal connected to the second comparator and the third comparator may be the same terminal, and similarly, the ground terminal connected to the second comparator and the third comparator may be the same terminal. In this case, the tenth capacitor and the eleventh capacitor arranged in parallel may be arranged between the power signal terminal and the ground terminal to further realize the signal filtering function, thereby improving the accuracy of the output result of the signal generating unit.

[0051] In addition, optionally, in the embodiments of the present invention, the specific structure of the excitation module is not limited to that shown in Figure 7 above, that is, the structure shown in Figure 7 is merely one specific embodiment for realizing the function of the excitation module, and the specific structure of the excitation module may further adopt other structures capable of realizing the function of the excitation module known to those skilled in the art, and is not limited here.

[0052] Optionally, in an embodiment of the present invention, as shown in FIG. 8, the current detection circuit 20 further includes an auxiliary module 24; Here, the auxiliary module 24 is connected to the second winding u2 of the electromagnetic induction coil L0, In the initialization stage where no current flows through the wire L0, a preset current signal is output to the second winding u2 so as to determine whether the excitation module 21 and the comparison module 22 can operate normally.

[0053] In addition, the first winding and the second winding in the electromagnetic induction coil are two different windings. When no current flows through the wire, a current signal can be input to the second winding to simulate a situation where there is leakage current in the wire passing through the electromagnetic induction coil. When the excitation module inputs an excitation signal to the first winding, there is a current in the second winding, which may cause the magnetic field caused by the excitation signal to be changed. However, if the excitation module and the comparison module can determine that the feedback signal induced in the first winding is greater than the reference signal, then it can be determined that the excitation module and the comparison module can operate normally and effectively, and thus self-detection for the current detection circuit is realized.

[0054] Optionally, in an embodiment of the present invention, the auxiliary module 24 includes a current generator.

[0055] In this way, the function of the auxiliary module can be realized with a simple structure, and self-detection for the current detection circuit is realized.

[0056] Here, the structure of the current generator in the auxiliary module 24 is as shown in Fig. 9, that is, it includes a number of resistors (designated as F9, F10 and F11), one transistor (designated as Q3) and one constant voltage diode (designated as Q2), and the specific connection relationship is as shown in Fig. 9, and will not be described in further detail here. Here, CHK is a self-detection signal for simulating the occurrence of leakage current to detect whether the induction coil can be normally induced, and the self-detection signal outputs a preset current signal to the second winding u2 through the action of the resistors, transistors and constant voltage diodes shown in Fig. 9.

[0057] Of course, the specific structure of the current generator may also be other structures capable of generating current known to those skilled in the art, and may be specifically installed and selected according to actual needs, and is not limited herein.

[0058] Hereinafter, the operation process of the above current detection circuit according to the embodiment of the present invention will be described with reference to the structural diagram shown in FIG.

[0059] The second comparator B2 and the third comparator B3 cooperate with the thirteenth resistor R13 and the nineteenth resistor R19 to input the generated signals to the first pin and the second pin of the driver Q1, respectively. 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 act as a pull-up to improve the output capability of the driver Q1, so that the excitation signal (wherein the frequency and amplitude of the excitation signal may be adjusted according to actual needs) output by the driver Q1 through the fifth and sixth pins is more accurate and effective; Then, by using the combination 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 to generate a magnetic field in the electromagnetic induction coil; If there is a leakage current in the wire passing through the electromagnetic induction coil, the presence of the leakage current will cause a change in the magnetic field, causing the first winding u1 to output a feedback signal; Here, the first diode D1 to the fourth diode D4 have a unidirectional conduction action, and therefore act to protect the excitation module, and can prevent the excitation module from being affected by the feedback signal. The feedback signal may be firstly transmitted to the first input terminal and the second input terminal of the first operational amplifier Y1 through a voltage dividing process of the fifteenth resistor R15, the sixteenth resistor R16, the eighteenth resistor R18, the twentieth resistor R20 and the twenty-first resistor R21; The first operational amplifier Y1 amplifies the feedback signal in cooperation with the first resistor R1 and the tenth resistor R10, and transmits the amplified feedback signal to the comparison unit 22a; In the comparison unit 22a, the first capacitor C1 to the fifth capacitor C5 perform filtering to extract an effective signal from the amplified feedback signal, and the eighth resistor R8, the ninth resistor R9 and the second operational amplifier Y2 cooperate to amplify the extracted effective signal, and then the sixth resistor R6 and the seventh resistor R7 output the first signal Z1, which is then transmitted to the first comparator B1. The first comparator B1 can follow and compare a reference voltage, and transmit the output second signal Z2 to the third operational amplifier Y3. In order to guide the external device to respond immediately and effectively and improve the safety and reliability of the charging process, an indication signal K0 (for example, but not limited to, a high level signal) is output through the cooperative amplification action of the third operational amplifier Y3, the third resistor R3 to the fifth resistor R5 and the sixth capacitor C6 to notify the external device that there is a leakage current in the wire.

[0060] It should be noted that the current detection circuit according to the embodiment of the present invention is composed of simple elements, and therefore can contribute to reducing the manufacturing costs of the current detection circuit. In addition, the overall area occupied by the current detection circuit is small, and the overall dimensions of the current detection circuit are reduced, making it easier to install and use in various charging systems, thereby greatly improving the practicality of the current detection circuit.

[0061] In addition, depending on the waveform of the current signal, the types of current leakage current mainly include a sinusoidal current signal, a current signal having a pulsating DC component, and a current signal having a smooth DC component. The current detection circuit according to the embodiment of the present invention can realize detection of the above three types of leakage current, so that it is not limited by the type of leakage current to be detected in the actual use process, and therefore the current detection circuit according to the embodiment of the present invention has a wide range of use.

[0062] Based on the same inventive idea, an embodiment of the present invention provides a charging system, as shown in FIG. 10, including a charging device 101, an electromagnetic induction coil 10, a control circuit 103 and a current detection circuit 20; The current detection circuit 20 is the same as the above current detection circuit according to the embodiment of the present invention, and the current detection circuit 20 is respectively connected to the electromagnetic induction coil 10 and the control circuit 103, and the control circuit 103 is connected to the charging device 101 via a first wire 104, and the first wire 104 passes through the electromagnetic induction coil 10; When it is determined that there is a leakage current in the first wire 104, the current detection circuit 20 outputs an indication signal K0. The control circuit may control the charging device 101 to stop supplying electrical energy to the outside when the instruction signal K0 is received, or may control the charging device 101 to supply electrical energy to the outside when the instruction signal K0 is not received.

[0063] In this way, the control circuit controls whether the charging equipment supplies electrical energy to the outside depending on whether the current detection circuit outputs an instruction signal, so that if there is a leakage current in the first wire passing through the electromagnetic induction coil, i.e., if a leakage situation occurs during the process of the charging equipment supplying electrical energy to the outside, the control circuit immediately disconnects the circuit through which the charging equipment supplies electrical energy to the outside, thereby causing the charging equipment to stop supplying electrical energy to the outside, thereby reducing the occurrence of harm and improving the safety and reliability of the charging process.

[0064] In addition, when the control circuit cuts off the circuit through which the charging equipment supplies electrical energy to the outside, the response speed of the control circuit can reach the ms level, and the charging equipment can cut off the circuit through which the charging equipment supplies electrical energy to the outside within as fast as 0.01 ms, greatly improving the control of the charging system and greatly improving the safety and reliability of the charging process.

[0065] Optionally, in an embodiment of the present invention, as shown in FIG. 10, the first wire may include a neutral wire and a live wire that can pass through the electromagnetic induction coil 10.

[0066] Specifically, in an embodiment of the present invention, as shown in FIG. 11, the control circuit 103 may be connected to the charged equipment 102 via a second wire 105, and correspondingly, the second wire 105 may similarly include a neutral wire and a live wire.

[0067] Optionally, in an embodiment of the present invention, as shown in FIG. 11, the control circuit 103 may include a controller 103b and a switch 103a, where the switch 103a is disposed between the charging device 101 and the charged device 102, and the controller 103b may be connected to the switch 103a and the current detection circuit 20, respectively.

[0068] That is, the switch is located on the neutral and live wires, but the controller is not located on the neutral and live wires; When the controller receives an instruction signal, the controller may control the switch to be turned off to switch the connection between the charging equipment and the charged equipment and stop the charging process, or when the controller does not receive an instruction signal, the controller may control the switch to be turned on to maintain the connection between the charging equipment and the charged equipment and maintain the normal execution of the charging process.

[0069] And, at least one switch may be provided in the charging system; If one switch is provided, it may be provided on the neutral wire or on the live wire; Alternatively, if two switches are provided, one switch may be provided on the neutral line and the other switch may be provided on the live line.

[0070] Specifically, in an embodiment of the present invention, the switch may be, but is not limited to, a relay, and may further be other structures capable of realizing the function of a switch known to those skilled in the art, and is not limited thereto.

[0071] Optionally, in an embodiment of the present invention, the connection between the first winding and the current detection circuit is: A method 1 in which a wire is provided on both ends of the first winding, and the current detection circuit can realize a connection with the first winding through the wire; The first winding may include a second method, in which a welding point is provided at both ends of the first winding, and the current detection circuit is connected to the welding point in a welding manner to realize a connection with the first winding.

[0072] In practical situations, one may select one of the above methods 1 and 2 according to the practical situation to realize the connection between the first winding and the current detection circuit, so as to meet the requirements of different application scenarios and improve design flexibility.

[0073] Based on the same inventive idea, an embodiment of the present invention provides a leakage current detection method similar to the realization principle of the above-mentioned current detection circuit, and the specific realization form of the detection method may refer to the specific embodiment of the above-mentioned current detection circuit, and the overlapping parts will not be described.

[0074] Specifically, as shown in FIG. 12, the leakage current detection method according to the embodiment of the present invention includes: S1201: outputting an excitation signal to a first winding of an electromagnetic induction coil; S1202: determining whether there is a leakage current in a wire passing through the electromagnetic induction coil based on a feedback signal induced in the first winding and a preset reference signal; may include:

[0075] In this way, an excitation signal is output to the first winding in the electromagnetic induction coil, and based on the feedback signal and reference signal induced in the first winding, it is possible to determine whether or not there is a leakage current in the wire passing through the electromagnetic induction coil. Based on the determination result, it is possible to respond immediately and effectively to the leakage situation, reduce the occurrence of harm, improve the safety and reliability of the charging process, and also improve the response speed to the control of the charging process and improve the aging resistance. Furthermore, the scope of application of the current detection circuit is not limited by region or climate, which greatly expands the scope of application of the current detection circuit.

[0076] Optionally, in an embodiment of the present invention, determining whether there is a leakage current in a wire passing through the electromagnetic induction coil based on the feedback signal and the preset reference signal may include: determining whether the absolute value of the feedback signal is greater than a reference signal; If it is greater, determining that there is a leakage current in the wire; If not, determining that the wire has no leakage current.

[0077] It is obvious to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and the technical scope equivalent thereto, the present invention is intended to include these modifications and variations.

Claims

1. A current detection circuit, comprising: an excitation module and a comparison module; the excitation module is connected to a first winding of an electromagnetic induction coil; A wire is passed through the electromagnetic induction coil, the comparison module is connected to the excitation module; the excitation module outputs an excitation signal to the first winding and receives a feedback signal induced in the first winding; The comparison module determines whether there is a leakage current in the wire based on the feedback signal induced in the first winding and a preset reference signal; The current detection circuit further includes an auxiliary module; the auxiliary module is connected to a second winding of the electromagnetic induction coil; A current detection circuit, characterized in that it outputs a preset current signal to the second winding during an initialization stage in which no current flows through the wire, so as to determine whether the excitation module and the comparison module can operate normally.

2. The comparison module includes: determining whether the absolute value of the feedback signal is greater than the reference signal; If it is greater, it is determined that the wire has the leakage current; 2. The current detection circuit according to claim 1, wherein if the leakage current is not large, it is determined that the leakage current does not exist in the wire.

3. 2. The current sensing circuit of claim 1, wherein the excitation module includes a signal generator that generates the excitation signal.

4. the excitation module further includes a voltage divider unit connected between the signal generator and the first winding; 4. The current detection circuit according to claim 3, wherein the voltage divider unit performs a voltage division process on the excitation signal before outputting the excitation signal to the first winding.

5. The comparison module includes a comparison unit; The current detection circuit of claim 1, wherein the comparison unit identifies an effective signal and an interference signal in the feedback signal, amplifies and processes the effective signal to obtain a first signal, determines whether or not there is a leakage current in the wire based on the first signal and the reference signal, and outputs a second signal when it determines that there is a leakage current in the wire.

6. The comparison module further includes a first operational amplification unit connected between the comparison unit and the excitation module; 6. The current detection circuit of claim 5, wherein the first operational amplifier unit performs signal amplification processing on the feedback signal before identifying useful signals and interference signals in the feedback signal.

7. The comparison module further includes a second operational amplifier unit coupled to the comparison unit; 6. The current detection circuit according to claim 5, wherein the second operational amplifier unit performs power amplification processing on the second signal.

8. 2. The current sensing circuit of claim 1, wherein the auxiliary module includes a current generator.

9. 1. A charging system comprising: A charging device, an electromagnetic induction coil, a control circuit, and a current detection circuit according to any one of claims 1 to 8, the current detection circuit is connected to the electromagnetic induction coil and the control circuit, The control circuit is connected to the charging device via a first wire; The first wire is passed through the electromagnetic induction coil; the current detection circuit outputs an indication signal when it is determined that a leakage current exists in the first wire; The control circuit controls the charging device to stop supplying electrical energy to the outside when the instruction signal is received, and controls the charging device to supply electrical energy to the outside when the instruction signal is not received.

10. 10. The charging system of claim 9, wherein the first wires include a neutral wire and a live wire.

11. A leakage current detection method, comprising: an excitation module outputting an excitation signal to a first winding of the electromagnetic induction coil; A comparison module determines whether there is a leakage current in a wire passing through the electromagnetic induction coil based on a feedback signal induced in the first winding and a preset reference signal; During an initialization stage when no current flows through the wire, an auxiliary module connected to a second winding of the electromagnetic induction coil outputs a preset current signal to the second winding, so as to determine whether the excitation module and the comparison module can operate normally; A leakage current detection method comprising:

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