Leakage current detection device and method, and vehicle

Abstract

A leakage detection device that applies a leakage detection method, is applied to a vehicle, and includes a detection unit, a sampling unit, and a signal processing unit. The detection unit is separately connected to two-phase discharge paths of a power supply and is used to separately establish detection loops of the two-phase discharge paths when the power supply discharges. The sampling unit is electrically connected to the detection unit and is used to collect a first detection voltage of a first-phase discharge path and / or a second detection voltage of a second-phase discharge path from the detection loop. The signal processing unit is connected to the sampling unit, asynchronously receives the first detection voltage and the second detection voltage from the sampling unit, and is used to determine the leakage characteristics of the power supply according to the first detection voltage and the second detection voltage.

Description

[Technical Field]

[0001] Cross-reference of related applications This disclosure claims priority to Chinese Patent Application No. 202210898895.X, entitled “ELECTRIC LEAKAGE DETECTION DEVICE AND METHOD, AND VEHICLE,” filed on 28 July 2022. The entire contents of the above-mentioned referenced application are incorporated herein by reference.

[0002] This disclosure relates to the field of drive devices, and more particularly to electrical devices, methods, and vehicles for detecting leakage current. [Background technology]

[0003] As new energy electric vehicles develop, the demand for them increases, and the need for vehicles with discharge capabilities grows. When the vehicle's power supply provides power to external electrical devices, detecting and protecting against power leakage is a major challenge today.

[0004] Currently, in electric vehicle leakage detection, positive and negative DC power supplies are applied between the high-voltage loop and the vehicle body to form a loop with the overall insulation resistance of the vehicle. This method allows for the acquisition of changes in the overall insulation resistance of the vehicle. Since the device for detecting leakage is located between the high-voltage loop and the vehicle body, the operation of the leakage detection device requires an increase in the current flowing through the high-voltage loop, which affects the overall insulation performance of the vehicle. [Overview of the project] [Problems that the invention aims to solve]

[0005] In view of the above technical challenges, embodiments of the present disclosure propose an electrical device for detecting leakage current, a detection method, and a vehicle that performs fault detection using the electrical device for detecting leakage current, which can improve the reliability of leakage current detection in a power supply discharge loop and improve the insulation characteristics of the AC output terminal of a power supply. [Means for solving the problem]

[0006] One embodiment of the present disclosure discloses a device for detecting leakage current, the device for detecting leakage current comprising a detection unit, a sampling unit, and a signal processing unit, wherein the detection unit is separately connected to a first phase discharge path and a second phase discharge path, the first and second phase discharge paths being used to connect a power supply and transmit the electricity output when the power supply is discharged, and the detection unit is used to form a detection loop of the first and second phase discharge paths when the power supply is discharged. The sampling unit is electrically connected to the detection unit and is used to separately collect a first detection voltage of the first phase discharge path and a second detection voltage of the second phase discharge path from the detection loop. The signal processing unit is connected to the sampling unit and is used to asynchronously receive the first and second detection voltages from the sampling unit and to determine the leakage current characteristics of the power supply based on the first and second detection voltages.

[0007] Optionally, the detection unit includes a first detection circuit and a second detection circuit, the first detection circuit being connected between a first phase discharge path and low voltage ground to form a detection loop, and the second detection circuit being connected between a second phase discharge path and low voltage ground to form a detection loop. The sampling unit is used to collect a first detection voltage from the first detection circuit and a second detection voltage from the second detection circuit.

[0008] Optionally, the first detection circuit includes a first detection voltage stabilization module, a first unidirectional conduction module, and a sampling module, the first detection voltage stabilization module, the first unidirectional conduction module, and the sampling module being connected sequentially in series between a first phase discharge path and low-voltage ground to form a detection loop. The second detection circuit includes a second detection voltage stabilization module and a second unidirectional conduction module, the second detection voltage stabilization module, the second unidirectional conduction module, and the sampling module being connected sequentially in series between a second phase discharge path and low-voltage ground to form a detection loop.

[0009] Optionally, the first detection voltage stabilization module includes a first switch, the first unidirectional conduction module includes a first diode, and the sampling module includes a first resistor, a sampling node, and a sampling resistor. The first switch, the first diode, the first resistor, and the sampling resistor are connected sequentially in series between the first phase discharge path and low voltage ground to form a detection loop, the anode of the first diode is connected to the first switch, the cathode of the first diode is connected to the first resistor, and the sampling node is the node between the first resistor and the sampling resistor. The second detection voltage stabilization module includes a second switch, and the second unidirectional conduction module includes a second diode. The second switch, the second diode, the first resistor, and the sampling resistor are connected sequentially in series between the second phase discharge path and low voltage ground to form a detection loop, the anode of the second diode is connected to the second switch, and the cathode of the second diode is connected to the first resistor. The sampling unit collects the first and second detection voltages from the sampling node.

[0010] Optionally, a first detection voltage stabilization module includes a first detection voltage stabilization capacitor, a first unidirectional conduction module includes a first diode, and a sampling module includes a first resistor, a sampling node, and a sampling resistor. The first detection voltage stabilization capacitor, the first diode, the first resistor, and the sampling resistor are sequentially connected in series between a first phase discharge path and a low-voltage ground to form a detection loop. The anode of the first diode is connected to the first detection voltage stabilization capacitor, the cathode of the first diode is connected to the first resistor, and the sampling node is the node between the first resistor and the sampling resistor. The second detection voltage stabilization module includes a second detection voltage stabilization capacitor, and the second unidirectional conduction module includes a second diode. The second detection voltage stabilization capacitor, the second diode, the first resistor, and the sampling resistor are sequentially connected in series between the second phase discharge path and the low-voltage ground to form a detection loop. The anode of the second diode is connected to the second detection voltage stabilization capacitor, and the cathode of the second diode is connected to the first resistor. The sampling unit collects the first detection voltage and the second detection voltage from the sampling node.

[0011] Optionally, the sampling unit includes a differential operational amplifier, a second resistor, a third resistor, and a third capacitor, the positive terminal of the differential operational amplifier being connected to the sampling node and used to collect a first and second detection voltage from the sampling node. The second resistor and the third capacitor are connected in series between the negative terminal of the differential operational amplifier and device ground, the negative terminal of the differential operational amplifier being connected to the output terminal of the differential operational amplifier via the third resistor and used to increase or decrease the first and second detection voltages according to a preset ratio and to output the first and second detection voltages from the output terminal of the differential operational amplifier.

[0012] Optionally, the detection unit is further connected to a third phase discharge path, and the power supply is a three-phase AC power supply that outputs currents with equal amplitude, same frequency, and same phase difference through the first phase discharge path, the second phase discharge path, and the third phase discharge path.

[0013] Optionally, the detection unit includes a first detection circuit and a second detection circuit, the first detection circuit being connected between a first phase discharge path and device ground, and connected to the second phase discharge path via device ground to form a detection loop. The second detection circuit being connected between a second phase discharge path and device ground, and connected to the first phase discharge path via device ground to form a detection loop.

[0014] Optionally, the first detection circuit includes a first detection voltage stabilization module, a first path voltage stabilization module, a first voltage division module, and a sampling module. The first detection voltage stabilization module, the first voltage division module, and the sampling module are connected sequentially in series between the first phase discharge path and device ground, and the first path voltage stabilization module is connected between the second phase discharge path and device ground to form a detection loop. The second detection circuit includes a second detection voltage stabilization module, a second path voltage stabilization module, and a second voltage division module. The second detection voltage stabilization module, the second voltage division module, and the sampling module are connected sequentially in series between the second phase discharge path and device ground, and the second path voltage stabilization module is simultaneously connected between the first phase discharge path and device ground to form a detection loop.

[0015] Optionally, a first detection voltage stabilization module includes a first switch, a first voltage division module includes a first diode and a first resistor, a sampling module includes a sampling resistor and a sampling node, a first path voltage stabilization module includes a first path voltage stabilization capacitor, the first switch, first diode, first resistor, and sampling resistor are connected sequentially in series between a first phase discharge path and device ground, the anode of the first diode is connected to the first switch, the cathode of the first diode is connected to the first resistor, the sampling node is the node between the first resistor and the sampling resistor, and the first path voltage stabilization capacitor is simultaneously connected between device ground and a second phase discharge path to form a detection loop. The second detection voltage stabilization module includes a second switch, the second voltage division module includes a second diode and a second resistor, the second path voltage stabilization module includes a second path voltage stabilization capacitor, the second switch, second diode, second resistor, and sampling resistor are sequentially connected in series between the second phase discharge path and device ground, the anode of the second diode is connected to the second switch, the cathode of the second diode is connected to the second resistor, and the second path voltage stabilization capacitor is simultaneously connected between device ground and the first phase discharge path to form a detection loop. The sampling unit is used to collect the first detection voltage and the second detection voltage from the sampling node.

[0016] Optionally, a first detection voltage stabilization module includes a first detection voltage stabilization capacitor, a first path voltage stabilization module includes a first path voltage stabilization capacitor, a first voltage division module includes a first diode and a first resistor, and a sampling module includes a sampling node and a sampling resistor. The first detection voltage stabilization capacitor, the first diode, the first resistor, and the sampling resistor are connected sequentially in series between a first phase discharge path and device ground, the anode of the first diode is connected to the first detection voltage stabilization capacitor, the cathode of the first diode is connected to the first resistor, the sampling node is the node between the first resistor and the sampling resistor, and the first path voltage stabilization capacitor is simultaneously connected between device ground and a second phase discharge path to form a detection loop. The second detection voltage stabilization module includes a second detection voltage stabilization capacitor, the second voltage division module includes a second diode and a second resistor, the second path voltage stabilization module includes a second path voltage stabilization capacitor, the second detection voltage stabilization capacitor, the second diode, the second resistor, and the sampling resistor are connected sequentially in series between the second phase discharge path and device ground, the anode of the second diode is connected to the second detection voltage stabilization capacitor, the cathode of the second diode is connected to the second resistor, and the second path voltage stabilization capacitor is simultaneously connected between device ground and the first phase discharge path to form a detection loop. The sampling unit is used to collect the first detection voltage and the second detection voltage from the sampling node.

[0017] Optionally, the sampling unit includes a voltage follower, the positive phase terminal of the voltage follower is connected to a sampling node and used to collect a first and second detection voltage from the sampling node, and the negative phase terminal of the voltage follower is connected to the output terminal of the voltage follower and used to increase or decrease the collected first and second detection voltages according to a preset rate and to output the collected first and second detection voltages from the output terminal of the voltage follower.

[0018] Optionally, the signal processing unit includes a clamping circuit and a digital signal processor. The clamping circuit is connected to the sampling unit and the digital signal processor and is used to clamp the first and second detection voltages received from the sampling unit to a preset voltage range and to output the first and second detection voltages to the digital signal processor. The digital signal processor receives the first and second detection voltages and determines the leakage characteristics of the power supply based on the first and second detection voltages.

[0019] One embodiment of the present disclosure further discloses a device for detecting leakage current described above or a method for detecting leakage current applied to an electric vehicle. Specific steps include controlling a sampling unit to conduct a first detection circuit and collect a first detection voltage from the first detection circuit when the power supply is positively discharged through a first phase discharge path. When the power supply is positively discharged through a second phase discharge path, controlling a sampling unit to conduct a second detection circuit and collect a second detection voltage from the second detection circuit. The voltage difference between the first detection voltage and the second detection voltage is compared to a threshold voltage, and it is determined that a leakage fault has occurred in the power supply if the voltage difference is greater than the threshold voltage.

[0020] One embodiment of the present disclosure also discloses a vehicle including a device for detecting leakage current as described above, wherein the power supply is connected to a first phase discharge path and a second phase discharge path, the power supply discharges through the first phase discharge path and the second phase discharge path and outputs an alternating current, and the device for detecting leakage current is used to perform leakage current detection on the first phase discharge path and the second phase discharge path when the power supply is discharged.

[0021] Compared to prior art, the device for detecting leakage current provided by this disclosure establishes leakage current detection loops in the first and second phase discharge paths of the power supply, respectively, to directly and rapidly perform leakage current detection on the power supply discharge loop during power supply discharge. This effectively avoids the high impedance defect of the detection loop caused by directly placing the device for detecting leakage current between the high-voltage loops of the power supply, effectively improving the reliability of leakage current detection in the power supply discharge loop and significantly improving the insulation characteristics of the power supply AC output terminal. Furthermore, when there is no leakage current fault in the power supply discharge loop, the device for detecting leakage current is in a low-power consumption state, thereby reducing the consumption of electrical energy. The device for detecting leakage current has low overall power consumption and a simple structure, thereby significantly reducing the cost of using and manufacturing the circuit.

[0022] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings that may be used in the embodiments are briefly described below, although naturally the accompanying drawings in the following description are of some embodiments of this disclosure, and those skilled in the art may be able to obtain other drawings by following these without any creative effort. [Brief explanation of the drawing]

[0023] [Figure 1] This is a schematic block diagram of a drive device according to the first embodiment of the present disclosure. [Figure 2] Figure 1 is a circuit block diagram of a device for detecting leakage current, according to a second embodiment of the present disclosure. [Figure 3] Figure 2 is a schematic diagram of the module connection of the device for detecting ground faults. [Figure 4] Figure 3 is an equivalent circuit diagram of the device for detecting leakage current. [Figure 5] This is an equivalent circuit diagram of the device for detecting leakage current shown in Figure 3, according to a third embodiment of the present disclosure. [Figure 6]This is a schematic diagram of the connections between functional modules of the device for detecting leakage current in Figure 2, according to a fourth embodiment of the present disclosure. [Figure 7] Figure 6 is an equivalent circuit diagram of the device for detecting leakage current. [Figure 8] This is an equivalent circuit diagram of the device for detecting leakage current shown in Figure 6, according to a fifth embodiment of the present disclosure. [Figure 9] This is a flowchart of a method for detecting a ground fault according to the sixth embodiment of this disclosure. [Modes for carrying out the invention]

[0024] To facilitate understanding of this disclosure, the disclosure is described in more detail below with reference to the accompanying drawings. The accompanying drawings illustrate preferred embodiments of this disclosure. However, this disclosure may be implemented in many different forms and is not limited to the embodiments described herein. Rather, the purpose of providing these embodiments is to make the disclosure more thorough and comprehensive.

[0025] To illustrate specific embodiments that may be implemented by this disclosure, the following description of embodiments is provided with reference to the accompanying drawings. The sequential numbering of the components themselves, such as “First,” “Second,” etc., is used solely to distinguish the objects being described and has no sequential or technical meaning. However, the terms “connection” and “joining” in this disclosure are not specifically defined and all include direct and indirect connections (joins). The directional terms referred to in this disclosure, such as “up,” “down,” “front,” “back,” “left,” “right,” “inside,” “outside,” and “side,” are merely directions with reference to the accompanying drawings, and therefore the directional terms used do not suggest or imply that the devices or elements referred to in this disclosure must have a particular orientation or are constructed and operated in a particular orientation, but are for a better and clearer description and understanding of this disclosure and are therefore not to be understood as limitations on this disclosure.

[0026] It should be noted that, unless otherwise specified and limited in the description of this disclosure, the terms “installation,” “connection,” and “joining” should be understood in a broad sense. For example, these terms could refer to fixed or removable connections, integrated connections, mechanical connections, direct connections, indirect connections via an intermediate medium, or internal connections between two components. A person skilled in the art will understand the specific meaning of the above terms in this disclosure on a case-by-case basis. It should be noted that terms such as “first,” “second,” etc., in the description, claims, and drawings of this disclosure are used to distinguish different objects, rather than to indicate a specific order.

[0027] In addition, the terms “includes,” “may include,” “equip,” or “may equip” as used in this disclosure indicate the presence of a corresponding disclosed feature, operation, element, etc., and do not limit one or more other features, operations, elements, etc. Furthermore, the terms “includes” or “equip” indicate the presence of a corresponding feature, number, step, operation, element, element, component, or combination thereof disclosed in the specification, but do not exclude the presence or addition of one or more other features, numbers, steps, operations, elements, parts, or combinations thereof, and are intended to cover non-exclusive inclusion. In addition, when “may” is used to describe embodiments of this disclosure, it means “one or more embodiments of this disclosure.” Also, the term “exemplary” is intended to refer to an example or illustration.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art to the extent of this disclosure. Terms used in the description of this disclosure are for illustrative purposes only to describe specific embodiments and are not intended to limit this disclosure.

[0029] Referring to Figure 1, Figure 1 is a schematic block diagram of a drive device according to a first embodiment of the present disclosure. As shown in Figure 1, the drive device 100 is a vehicle capable of outputting electrical energy outside the vehicle body and includes a device 10 for detecting leakage current and a power supply 20, the device 10 for detecting leakage current is used to perform leakage current detection against a high-voltage loop when the vehicle outputs electrical energy to the outside.

[0030] Referring to Figure 2, Figure 2 is a circuit block diagram of a device for detecting leakage current shown in Figure 1, according to a second embodiment of the present disclosure. As shown in Figure 2, the device 10 for detecting leakage current includes a detection unit 11, a sampling unit 12, and a signal processing unit 13.

[0031] The detection unit 11 is connected separately to the first phase discharge path L and the second phase discharge path N, which are connected to the power supply 20 and used to transmit the electricity output when the power supply 20 is discharged, and the detection unit 11 is used to establish a detection loop between the first phase discharge path L and the second phase discharge path N when the power supply 20 is discharged.

[0032] The sampling unit 12 is electrically connected to the detection unit 11 and receives the first detection voltage U from the detection loop through the first phase discharge path L. LE and / or the second detection voltage U of the second phase discharge path N NE They are configured to be collected separately.

[0033] The signal processing unit 13 is connected to the sampling unit 12 and receives a first detection voltage U from the sampling unit 12. LE and the second detection voltage U NE It is configured to receive asynchronously and determine the leakage characteristics of the power supply, and the first detection voltage U LE and the second detected voltage U NE If the difference between the two values ​​is greater than the threshold voltage, it indicates that a leakage fault has occurred in power supply 20.

[0034] In one embodiment, the power supply 20 can also be a three-phase AC power supply. That is, the power supply 20 is a power supply that sequentially includes three AC potentials having the same frequency, the same equal amplitude, and a phase difference of 120°. Correspondingly, the power supply 20 outputs three currents having the same frequency, the same amplitude, and the same phase difference of 120° through the first-phase discharge path, the second-phase discharge path, and the third-phase discharge path, respectively. When the power supply 20 outputs current through the three-phase discharge path, the detection unit 11 is also connected to the first-phase discharge path, the second-phase discharge path, and the third-phase discharge path, and performs corresponding detection.

[0035] Referring to FIG. 3, FIG. 3 is a schematic diagram of the module connection of the device for detecting leakage in FIG. 2. As shown in FIG. 3, the detection unit 11 includes a first detection circuit 111 and a second detection circuit 112.

[0036] The first detection circuit 111 is connected between the first-phase discharge path L and the low-voltage ground GND to form a detection loop for detecting the first detection voltage U LE of the first-phase discharge path L. The second detection circuit 112 is connected between the second-phase discharge path N and the low-voltage ground GND to form a detection loop for detecting the second detection voltage U NE of the second-phase discharge path N.

[0037] When the power supply 20 outputs an alternating current and the first-phase discharge path L is positively discharged, the first detection circuit 111 is conducted, and the sampling unit 12 detects the first detection voltage U LE from the first detection circuit 111. When the power supply 20 outputs an alternating current and the second-phase discharge path N is positively discharged, the second detection circuit 112 is conducted, and the sampling unit 12 detects the second detection voltage U NE from the second detection circuit 112.

[0038] The first detection circuit 111 includes a first detection voltage stabilization module 111B, a sampling module 111E, and a first unidirectional conduction module 111D. The first detection voltage stabilization module 111B, the first unidirectional conduction module 111D, and the sampling module 111E are sequentially connected in series between a first phase discharge path L and a low-voltage ground GND to form a detection loop.

[0039] The second detection circuit 112 includes a second detection voltage stabilization module 112B and a second unidirectional conduction module 112D. The second detection voltage stabilization module 112B, the second unidirectional conduction module 112D, and the sampling module 111E are sequentially connected in series between the second phase discharge path N and the low-voltage ground GND to form a detection loop.

[0040] The sampling unit 12 is electrically connected to the detection unit 11, and the detection unit 11 receives the first detection voltage U from the detection loop through the first phase discharge path L. LE and / or the second detection voltage U of the second phase discharge path N NE Used to collect.

[0041] The signal processing unit 13 is connected to the sampling unit 12 and asynchronously receives a first detection voltage and a second detection voltage from the sampling unit 12, and is used to determine the leakage characteristics of the power supply. LE and the second detected voltage U NE If the difference between the two values ​​is greater than the threshold voltage, it indicates that a leakage fault has occurred in power supply 20.

[0042] Referring to Figure 4, Figure 4 is an equivalent circuit diagram of the device for detecting leakage current in Figure 3. As shown in Figure 4, the first detection voltage stabilization module 111B includes a first switch K1, the first unidirectional conduction module 111D includes a first diode D1, and the sampling module 111E includes a first resistor R1, a sampling node Q, and a sampling resistor Rx. The first switch K1, the first diode D1, the first resistor R1, and the sampling resistor Rx are sequentially connected in series between the first phase discharge path L and the low voltage ground GND to form a detection loop, the anode of the first diode D1 is connected to the first switch K1, the cathode of the first diode D1 is connected to the first resistor R1, and the sampling node Q is connected to the first detection voltage U by the sampling unit 12. LE A first resistor R1 is placed between the sampling resistor Rx to collect the signal.

[0043] The second detection voltage stabilization module 112B includes a second switch K2, and the second unidirectional conduction module 112D includes a second diode D2. The second switch K2, the second diode D2, the first resistor R1, and the sampling resistor Rx are sequentially connected in series between the second phase discharge path N and the low-voltage ground GND to form a detection loop. The anode of the second diode D2 is connected to the second switch K2, and the cathode of the second diode D2 is connected to the first resistor R1. The sampling unit 12 receives the second detection voltage U from the sampling node Q through the second phase discharge path N. NE Collect them.

[0044] The sampling unit 12 includes a differential operational amplifier 122, a third capacitor CY3, a second resistor R2, and a third resistor R3. The third resistor R3 is connected between the reverse-phase terminal in2 of the differential operational amplifier 122 and the output terminal out of the differential operational amplifier 122. The second resistor R2 and the third capacitor CY3 are connected in series with the device ground E and the reverse-phase terminal in2 of the differential operational amplifier 122. The positive-phase terminal in1 of the differential operational amplifier 122 is connected to the sampling node Q, and the differential operational amplifier 122 receives a first detection voltage U through the sampling node Q. LE and the second detection voltage U NE Collect each of them.

[0045] If the voltage of the first phase discharge path L is greater than the voltage of the second phase discharge path N, the differential operational amplifier 122 detects the first detection voltage U of the first phase discharge path L via the first detection circuit 111. LE The differential operational amplifier 122 detects the second detection voltage U of the second phase discharge path N via the second detection circuit 112 when the voltage of the second phase discharge path N is greater than the voltage of the first phase discharge path L. NE Detects.

[0046] When the voltage of the first phase discharge path L is greater than the voltage of the second phase discharge path N, the positive phase terminal in1 of the differential operational amplifier 122 is connected to the sampling node Q, which is connected to the first phase discharge path L by the first detection circuit 111, and the first detection voltage U is transmitted from the sampling node Q. LE The first detection voltage U is collected, and the reverse-phase terminal in2 is connected to device ground E via a third detection circuit, which includes a second resistor R2 and a third capacitor CY3. When the circuit is in operation, the positive output passes through the first switch K1, the first diode D1, and the first resistor R1 to the positive-phase terminal in1 of the differential operational amplifier 122, and the negative input passes through device ground E, the second resistor R2, and the third capacitor CY3 to the reverse-phase terminal in2, and then the first detection voltage U is collected from the output terminal out of the differential operational amplifier 122. LE The following will be output.

[0047] If the voltage of the second phase discharge path N is greater than the voltage of the first phase discharge path L, the positive phase terminal in1 of the differential operational amplifier 122 is connected to the sampling node Q, which is connected to the second phase discharge path N by the second detection circuit 112, and the second detection voltage U is transmitted from the sampling node Q. NE The voltage is collected, and the reverse-phase terminal in2 is connected to device ground E via a third detection circuit. When the circuit is operating, the positive output passes through the second switch K2, the second diode D2, and the first resistor R1 to the positive-phase terminal in1 of the differential operational amplifier 122, and the negative input passes through device ground E, the second resistor R2, and the third capacitor CY3 to the reverse-phase terminal in2, and then the second detection voltage U is collected from the output terminal out of the differential operational amplifier 122. NE The following will be output.

[0048] The differential operational amplifier 122 receives the first detected voltage U LE and the second detection voltage U NE This is transmitted to the signal processing unit 13 via the output terminal out.

[0049] The signal processing unit 13 includes a clamping circuit 131 and a digital signal processor (DSP) 132. The clamping circuit 131 is connected to the output terminal out of the differential operational amplifier 122 and the digital signal processor 132, and a first detection voltage U LE and the second detection voltage U NE It is used to adjust the received voltage value to a preset range. The digital signal processor 132 uses the first detected voltage U LE and the second detected voltage U NE Used to compare and in digital format. First detection voltage U LE and the second detected voltage U NE If the difference between the two values ​​is greater than a preset threshold, this indicates that a leakage fault has occurred in power supply 20.

[0050] The device for detecting leakage current disclosed in this embodiment is based on the national standard "GB 18384.2020 Electric Vehicles Safety Requirements," where the insulation resistance between the AC discharge path, i.e., the first phase discharge path L and the second phase discharge path N, is...

number

[0051] Referring to Figure 5, Figure 5 is an equivalent circuit diagram of a device for detecting leakage current in Figure 3, provided by a third embodiment of the present disclosure. As shown in Figure 5, the first detection voltage stabilization module 111B includes a first detection voltage stabilization capacitor CY1, the first unidirectional conduction module 111D includes a first diode D1, and the sampling module 111E includes a first resistor R1, a sampling node Q, and a sampling resistor Rx. The first detection voltage stabilization capacitor CY1, the first diode D1, the first resistor R1, and the sampling resistor Rx are connected in series sequentially to a first phase discharge path L and a low voltage ground terminal GND to form a detection loop. The anode of the first diode D1 is connected to the first detection voltage stabilization capacitor CY1, the cathode of the first diode D1 is connected to the first resistor R1, and the sampling node Q allows the sampling unit 12 to detect the first detection voltage U LE This is the node between the first resistor R1 for collecting data and the sampling resistor Rx.

[0052] The second detection voltage stabilization module 112B includes a second detection voltage stabilization capacitor CY2, and the second unidirectional conduction module 112D includes a second diode D2. The second detection voltage stabilization capacitor CY2, the second diode D2, the first resistor R1, and the sampling resistor Rx are sequentially connected in series to the second phase discharge path N and the low voltage ground GND to form a detection loop, the anode of the second diode D2 is connected to the second detection voltage stabilization capacitor CY2, and the cathode of the second diode D2 is connected to the first resistor R1. The sampling unit 12 receives the second detection voltage U of the second phase discharge path N via the sampling node Q. NE Collect them.

[0053] The sampling unit 12 includes a differential operational amplifier 122, a third capacitor CY3, a second resistor R2, and a third resistor R3. The third resistor R3 is connected between the reverse-phase terminal in2 of the differential operational amplifier 122 and the output terminal out of the differential operational amplifier 122. The second resistor R2 and the third capacitor CY3 are connected in series with the device ground E and the reverse-phase terminal in2 of the differential operational amplifier 122. The positive-phase terminal in1 of the differential operational amplifier 122 is connected to the sampling node Q, and the differential operational amplifier 122 receives a first detection voltage U through the sampling node Q. LE and the second detection voltage U NE Collect each of them.

[0054] If the voltage of the first phase discharge path L is greater than the voltage of the second phase discharge path N, the differential operational amplifier 122 detects the first detection voltage U of the first phase discharge path L via the first detection circuit 111. LE The differential operational amplifier 122 detects the second detection voltage U of the second phase discharge path N via the second detection circuit 112 when the voltage of the second phase discharge path N is greater than the voltage of the first phase discharge path L. NE Detects.

[0055] If the voltage of the first phase discharge path L is greater than the voltage of the second phase discharge path N, the positive phase terminal in1 of the differential operational amplifier 122 is connected to the sampling node Q, which is connected to the first phase discharge path L via the first detection circuit 111, and the first detection voltage U is transmitted from the sampling node Q. LE The first detection voltage U is collected, and the reverse-phase terminal in2 is connected to device ground E by a third detection circuit, which includes a second resistor R2 and a third capacitor CY3. When the circuit is in operation, the positive output passes through the first detection voltage stabilizing capacitor CY1, the first diode D1, and the first resistor R1 to the positive-phase terminal in1 of the differential operational amplifier 122, the negative input passes through device ground E, and the second resistor R2 and the third capacitor CY3 are connected to the reverse-phase terminal in2, and then the first detection voltage U is collected from the output terminal out of the differential operational amplifier 122. LE The following will be output.

[0056] If the voltage of the second phase discharge path N is greater than the voltage of the first phase discharge path L, the positive phase terminal in1 of the differential operational amplifier 122 is connected to the sampling node Q and to the second phase discharge path N via the second detection circuit 112, and the second detection voltage U is transmitted from the sampling node Q. NE The signal is collected, and the reverse-phase terminal in2 is connected to device ground E by a third detection circuit. When the circuit is in operation, the positive output passes through the second detection voltage stabilizing capacitor CY2, the second diode D2, and the first resistor R1 to the positive-phase terminal in1 of the differential operational amplifier 122, and the negative input passes through device ground E, resistor R2, and the third capacitor CY3 to the reverse-phase terminal in2, and then the second detection voltage U is collected from the output terminal out of the differential operational amplifier 122. NE The following will be output.

[0057] The differential operational amplifier 122 receives the first detected voltage U LE and the second detection voltage U NE This is transmitted to the signal processing unit 13 via the output terminal out.

[0058] The signal processing unit 13 includes a clamping circuit 131 and a digital signal processor (DSP) 132. The clamping circuit 131 is connected between the output terminal out of the differential operational amplifier 122 and the digital signal processor 132, and a first detection voltage U LE and the second detection voltage U NE It is used to adjust the received voltage value to a preset range. The digital signal processor 132 uses the first detected voltage U LE and the second detected voltage U NE Used to compare and in digital format. First detection voltage U LE and the second detected voltage U NE If the difference between the two values ​​is greater than a preset threshold, this indicates that a leakage fault has occurred in power supply 20.

[0059] From the virtual short-circuit characteristics of the operational amplifier, it can be seen that the voltage at the positive-sequence terminal in1 of the differential operational amplifier 122 and the voltage at the negative-sequence terminal in2 of the differential operational amplifier 122 are equal. The resistance value of the third resistor R3 and the resistance value of the sampling resistor Rx are equal to the resistance value of the feedback resistor Rf of the differential operational amplifier, i.e., Rx=R3=Rf. The resistance values ​​of the first resistor R1 and the second resistor R2 are equal, both being R, i.e., R1=R2=R. The first detection voltage stabilizing capacitor CY1, the second detection voltage stabilizing capacitor CY2, and the third capacitor CY3 are equal, i.e., CY1=CY2=CY3. In this case, the differential operational amplifier 122 is at the common-mode voltage U LE =(U L -U E Outputs Rf / R.

[0060] If the voltage of the second phase discharge path N is greater than the voltage of the first phase discharge path L, the second detection circuit 112 is activated, and the second detection voltage U NE Detect U NE =(U R -U E )*Rf / R.

[0061] JPEG0007870397000002.jpg8163

[0062] The "GB / T18384-2020 Electric Vehicles Safety Requirements" specifies requirements for leakage current in new energy electric vehicles, stating that at maximum operating voltage, the minimum insulation resistance of the AC circuit should be greater than 500 Ω / V, and the effective value of the maximum operating voltage is 220 V. The national standard states that the insulation resistance on the AC side is

number

number

[0063] If a leakage fault occurs in the first phase discharge path L to ground and / or the second phase discharge path N to ground, the first detection voltage U decreases as the insulation resistance RL of the first phase discharge path L to device ground decreases. LE As a result, the voltage UL of the first phase discharge path L relative to ground decreases, and at the same time, the voltage U of the first phase discharge path L relative to ground decreases. L and the voltage U of the second phase discharge path N relative to ground. N A large voltage difference occurs between the two. This occurs when the deviation value of the common-mode voltage reaches a certain threshold M, i.e., |U LE -U NE If M is detected, a ground fault is reported and the discharge is terminated.

[0064] The common-mode voltage deviation threshold M is determined by connecting a 110kΩ resistor in parallel to the path between the first or second phase discharge path N of the entire vehicle and the vehicle body of the drive device 100, and by performing software matching. The threshold M can also be adjusted according to the specific needs of the drive device 100, and is not limited to this disclosure.

[0065] The device 10 for detecting leakage current provided in this embodiment can ensure detection accuracy while making the insulation resistance between the AC ports of the power supply 20, i.e., between the first phase discharge path L and the second phase discharge path N, 20 MΩ or more.

[0066] Referring to Figure 6, Figure 6 is a schematic connection diagram of the functional module of the device for detecting leakage current in Figure 2, as disclosed in a fourth embodiment of the present disclosure. As shown in Figure 6, the power supply 20 converts the received direct current DC to alternating current AC and outputs electrical energy to an electrical device outside the vehicle body via a first phase discharge path L and a second phase discharge path N.

[0067] The detection unit 11 includes a first detection circuit 111 and a second detection circuit 112.

[0068] The first detection circuit 111 is connected between the first phase discharge path L and the device ground E, and is connected by the device ground E to the second phase discharge path N, forming a detection loop for detecting the common-mode voltage between the first phase discharge path L and the device ground terminal E. The device ground E is connected to earth by the vehicle body of the drive device 100.

[0069] The second detection circuit 112 is connected between the second phase discharge path N and the device ground E, and is connected to the first phase discharge path L by the device ground E, and detects the common-mode voltage between the second phase discharge path N and the device ground E, i.e., the second detection voltage U. NE Form a detection loop to detect the detection.

[0070] The current output by the power supply 20 is an alternating current. When the first phase discharge path L discharges positively, the first detection circuit 111 conducts, and the sampling unit 12 receives the first detection voltage U from the first detection circuit. LEThe second phase discharge path N discharges positively, the second detection circuit 112 conducts, and the sampling unit 12 receives the second detection voltage U from the second detection circuit 112. NE Detects.

[0071] The first detection circuit 111 includes a first path voltage stabilization module 111A, a first detection voltage stabilization module 111B, a first voltage division module 111C, and a sampling unit 111E. The first detection voltage stabilization module 111B, the first voltage division module 111C, and the sampling module 111E are sequentially connected in series between the first phase discharge path L and the device ground E, and the first path voltage stabilization module 111A is simultaneously connected between the second phase discharge path and the device ground E to form a detection loop.

[0072] When the first detection circuit 111 is activated, the first detection voltage stabilization module 111B is used to maintain the stability of the voltage received by the first detection circuit 111 from the first phase discharge path L. The first path voltage stabilization module 111A is used to maintain the stability of the voltage transmitted by the first detection circuit 111 to the second phase discharge path N. The first voltage division module 111C is used to divide the voltage within the first detection circuit 111 and at the same time provide a unidirectional conduction function from the first phase discharge path L to device ground E. The sampling module 111E transmits the first detection voltage U to the sampling unit 12. LE It is used to provide.

[0073] The second detection circuit 112 includes a second path voltage stabilization module 112A, a second detection voltage stabilization module 112B, and a second voltage division module 112C. The second detection voltage stabilization module 112B, the second voltage division module 112C, and the sampling module 111E are sequentially connected in series between the second phase discharge path N and the device ground E. Simultaneously, the second path voltage stabilization module 112A is connected between the first phase discharge path L and the device ground E to form a detection loop.

[0074] When the second detection circuit 112 conducts, the second detection voltage stabilization module 112B is used to maintain the stability of the voltage received by the second detection circuit 112 from the second phase discharge path N. The second path voltage stabilization module 112A is used to maintain the stability of the voltage transmitted to the first phase discharge path by the second detection circuit 112. The second voltage division module 112C is used to divide the voltage within the second detection circuit 112 and at the same time provide a unidirectional conduction function from the second phase discharge path N to device ground E.

[0075] The sampling unit 12 is electrically connected to the detection unit 11 and receives the first detection voltage U from the detection loop through the first phase discharge path L. LE and / or the second detection voltage U of the second phase discharge path N NE Used to collect.

[0076] The signal processing unit 13 is connected to the sampling unit 12 and receives a first detection voltage U from the sampling unit 12. LE and the second detection voltage U NE The first detected voltage U is received asynchronously and used to determine the leakage characteristics of the power supply 20. LE and the second detected voltage U LE If the voltage difference between the two points is greater than the threshold voltage, this indicates that a leakage fault has occurred in power supply 20.

[0077] See also Figure 7, which is an equivalent circuit diagram of the device for detecting leakage current in Figure 6. As shown in Figure 7, in the first detection circuit 111, the first path voltage stabilization module 111A includes a first path voltage stabilization capacitor C1, the first detection voltage stabilization module 111B includes a first switch K1, the first voltage division module 111C includes a first diode D1 and a first resistor R1, and the sampling module 111E includes a sampling node Q and a sampling resistor Rx. Of these, the first switch K1, the first diode D1, the first resistor R1, and the sampling resistor Rx are connected in series between the first phase discharge path L and the device ground E, and the anode of the first diode D1 is connected to the first phase discharge path L and the device ground E. Switch K1, the cathode of the first diode D1 is connected to the first resistor R1, the sampling node Q is located at the node between the first resistor R1 and the sampling resistor Rx, the first path voltage stabilizing capacitor C1 is connected to the second phase discharge path between N and device ground E, and the first detection circuit 111 forms a common-mode voltage detection loop.

[0078] The first switch K1 is connected between the first phase discharge path L and the first diode D1 and is used to control the detection execution and detection stop of the first detection circuit 111. The sampling resistor Rx is connected between the first resistor R1 and device ground E and is used to provide a voltage sampling point to the sampling unit 12. The sampling node Q is set between the first resistor R1 and the sampling resistor Rx. The sampling unit 12 is connected to the sampling node Q and is used to collect the voltage across the sampling resistor Rx when the first detection circuit 111 detects the common-mode voltage of the first phase discharge path L. The voltage value is the first detection voltage U LE But so.

[0079] In the second detection circuit 112, the second path voltage stabilization module 112A includes a second path voltage stabilization capacitor C2, the second detection voltage stabilization module 112B includes a second switch K2, and the second voltage division module includes a second diode D2 and a second resistor R2. The second switch K2, the second diode D2, and the second resistor R2 are sequentially connected in series between the second phase discharge path N and the sampling node Q. The anode of the second diode D2 is connected to the second switch K2, the cathode of the diode D2 is connected to the second resistor R2, and the second path voltage stabilization capacitor C2 is connected between the first phase discharge path L and the device ground E. As a result, a detection loop is formed between the second phase discharge path N, the second switch K2, the second diode D2, the second resistor R2, the sampling resistor Rx, the device ground E, the second path voltage stabilization capacitor C2, and the first phase discharge path L. The sampling unit 12 detects a second detection voltage U based on the voltage of the sampling node Q. NE Obtain it.

[0080] The sampling unit 12 includes a voltage follower 121. The positive phase terminal in1 of the voltage follower 121 is connected to the sampling node Q, and the negative phase terminal in2 of the voltage follower 121 is connected to the output terminal out of the voltage follower 121, which is connected to the first detected voltage U LE and the second detection voltage U NE It is connected to a signal processing unit 13 for collecting the first detection voltage U, and the output terminal out is connected to the first detection voltage U LE and the second detection voltage U NE This is transmitted to the signal processing unit 13.

[0081] The signal processing unit 13 includes a clamping circuit 131 and a digital signal processor (DSP) 132. The clamping circuit 131 is connected between the output terminal out of the voltage follower 121 and the digital signal processor 132, and the first detection voltage U LE and the second detection voltage U NEIt is used to clamp the received voltage value within a preset voltage range. The digital signal processor 132 receives the first detection voltage U LE and the second detection voltage U NE in digital form and is used to compare the first detection voltage U LE with the second detection voltage U NE in digital form. If the difference between the voltage U LE and the second detection voltage U NE is greater than a preset threshold value, this indicates that a leakage fault has occurred in the power supply 20.

[0082] When the power supply 20 discharges through the first phase discharge path L and the second phase discharge path N, if no leakage fault has occurred, the common - mode voltage between the first phase discharge path L and the device ground E is the same as the common - mode voltage between the second phase discharge path N and the device ground E. At the same time, no current flows through the detection unit 11 in the device 10 for detecting leakage, the sampling unit 12 does not need to collect the first detection voltage U LE nor the second detection voltage U LE either, and the signal processing unit 13 does not need to execute the determination of the leakage characteristics of the power supply 20, and the entire device 10 for detecting leakage is in a low - power consumption state.

[0083] If there is a voltage difference between the common - mode voltage between the first phase discharge path L and the device ground E and the common - mode voltage between the second phase discharge path N and the device ground E, the detection unit 11 detects the first detection voltage U LE by the first detection circuit 111 and / or detects the second detection voltage U NE by the second detection circuit 112. Then, the sampling unit 12 and the signal processing unit 13 execute subsequent detection and determination in sequence.

[0084] Specifically, when the driving device 100 turns on the discharging function, that is, when supplying power to an electrical device outside the vehicle body, the power supply 20 converts direct current into alternating current. The first switch K1, the first diode D1, the first resistor R1, the sampling resistor Rx, and the first path voltage stabilizing capacitor C1 in the first detection circuit 111 form a detection loop between the first phase discharging path L and the second phase discharging path N. The voltage follower 121 in the sampling unit 12 collects the first detection voltage U LE from the sampling node Q and transmits the first detection voltage U LE to the clamping circuit 131. The clamping circuit 131 clamps the received first detection voltage U LE and transmits it to the digital signal processor 132.

[0085] Alternatively, in the second detection circuit 112, from the detection loop between the second phase discharging path N and the first phase discharging path L, there are the second switch K2, the second diode D2, the second resistor R2, the sampling resistor Rx, and the second path voltage stabilizing capacitor C2. The voltage follower 121 in the sampling unit 12 collects the second detection voltage U NE from the sampling node Q and transmits the second detection voltage U NE to the clamping circuit 131. The clamping circuit 131 clamps the received second detection voltage U NE and transmits it to the digital signal processor 132.

[0086] Among these, the voltage follower 121 is connected to the low voltage ground GND. A fourth resistor R4 is provided between the low voltage ground GND and the device ground E. To avoid crosstalk between the low voltage ground GND and the device ground E, the potentials between the low voltage ground GND and the device ground E are the same.

[0087] The digital signal processor 132 compares the received first detection voltage U LE and / or the second detection voltage U NE in digital form. The first detection voltage U LEand the second detected voltage U NE If the difference between the first detection voltage U is greater than a preset threshold, this indicates that the power supply 20 has a leakage fault. LE and the second detected voltage U NE It is not necessary to specifically identify the two. The digital signal processor 132 detects the first detection voltage U LE or second detection voltage U NE Upon receiving the first detection voltage U LE Detects the second detection voltage U NE It is sufficient to obtain the first detected voltage U LE and the second detected voltage U NE The difference between the two may be calculated, or the second detection voltage U NE The first detection voltage U via LE The first detection voltage U may be obtained, and then the first detection voltage U LE and the second detected voltage U NE The difference between the two can also be calculated.

[0088] When there is no leakage fault in the discharge circuit of power supply 20, the device 10 for detecting leakage is in a low-power state. For example, power supply 20 outputs 220V AC power through a first phase discharge path L and a second phase discharge path N, which is used to supply power to external electrical devices. When no leakage fault occurs, the common-mode voltage between the first phase discharge path L and the equipment ground E is 110V, the common-mode voltage between the second phase discharge path N and the device ground E is 110V, there is no voltage difference between the first phase discharge path L and the second phase discharge path N, no current flows between the first detection circuit 111 and the second detection circuit 112, and the device for detecting leakage is in a low-power state.

[0089] The sampling unit 12 detects a first detection voltage U via the first detection circuit 111. LE Either collect the second detection voltage U via the second detection circuit 112. NE When collecting the signal, the signal processing unit 13, according to the AC characteristics, sets the first detection voltage U LE Based on this, the second detection voltage U NEThe second detection voltage U can be calculated, or NE Based on this, the first detected voltage U LE The first detection voltage U can then be calculated. LE and the second detected voltage U NE The voltage difference between the two points can be calculated.

[0090] For example, if a leakage fault occurs, and the common-mode voltage between the first phase discharge path L and the device ground E is 160V, the signal processing unit 13 can calculate the common-mode voltage between the second phase discharge path N and the device ground E based on the voltage between the first phase discharge path L and the device ground E. Alternatively, if the common-mode voltage between the second phase discharge path N and the device ground E collected by the sampling unit 12 is 60V, there is a voltage difference between the first phase discharge path L and the second phase discharge path N.

[0091] The first detection circuit 111 and the second detection circuit 112 are conducted at different times, and the first detection circuit 111 detects the first detection voltage U LE and the second detection voltage U NE The first detected voltage U can be detected and sampled. The digital signal processing unit processes the first detected voltage U LE and the second detected voltage U NE The difference between the two is determined, and if the difference is greater than the threshold voltage, this indicates that a leakage fault is occurring when power supply 20 is supplying power.

[0092] The device 10 for detecting leakage current provided in this embodiment can ensure detection accuracy while making the insulation resistance between the AC ports of the power supply 20, i.e., between the first phase discharge path L and the second phase discharge path N, 10 MΩ or more.

[0093] See also Figure 8, which is an equivalent circuit diagram of the device for detecting leakage current in Figure 6, provided by a fifth embodiment of the present disclosure. As shown in Figure 8, in the first detection circuit 111, the first path voltage stabilization module 111A includes a first path voltage stabilization capacitor C1, the first detection voltage stabilization module 111B includes a first detection voltage stabilization capacitor CY1, the first voltage division module 111C includes a first diode D1 and a first resistor R1, and the sampling module 111E includes a sampling node Q and a sampling resistor Rx. Of these, the first detection voltage stabilization capacitor CY1, the first diode D1, the first resistor R1, and the sampling resistor Rx are connected in series between the first phase discharge path L and the device ground E. The anode of the first diode D1 is connected to the first detection voltage stabilization capacitor CY1, the cathode of the first diode D1 is connected to the first resistor R1, the sampling node Q is located between the first resistor R1 and the sampling resistor Rx, the first path voltage stabilization capacitor C1 is connected between the second phase discharge path N and the device ground E, and the first detection circuit 111 forms a common-mode voltage detection loop.

[0094] A second detection stabilization capacitor CY2 is connected between the first phase discharge path L and the first diode D1 to increase the impedance in the detection loop and maintain the voltage stability of the first detection circuit 111. A sampling resistor Rx is connected between the first resistor R1 and the device ground E and is used to provide a voltage sampling point to the sampling unit 12. A sampling node Q is provided between the first resistor R1 and the sampling resistor Rx. The sampling unit 12 is connected to the sampling node Q and detects the voltage across the sampling resistor Rx, i.e., the first detection voltage U, when the first detection circuit 111 detects the common-mode voltage of the first phase discharge path L. LE Used to collect.

[0095] In the second detection circuit 112, the second path voltage stabilization module 112A includes a second path voltage stabilization capacitor C2, the second detection voltage stabilization module 112B includes a second detection voltage stabilization capacitor CY2, and the second voltage division module includes a second diode D2 and a second resistor R2. The second detection voltage stabilization capacitor CY2, the second diode D2, and the second resistor R2 are sequentially connected in series between the second phase discharge path N and the sampling node Q, the anode of the second diode D2 is connected to the second detection voltage stabilization capacitor CY2, the cathode of the second diode D2 is connected to the second resistor R2, and the sampling node Q is located between the first resistor R1 and the sampling resistor Rx. Simultaneously, the second path voltage stabilizing capacitor C2 is connected between the first phase discharge path L and the device ground E, and as a result, a detection loop is formed between the second phase discharge path N, the second detection voltage stabilizing capacitor CY2, the second diode D2, the resistor R2, the sampling resistor Rx, the device ground E, the second path voltage stabilizing capacitor C2, and the first phase discharge path L. The sampling unit 12 obtains the second detection voltage U by collecting the voltage at the sampling node Q. NE Obtain it.

[0096] The capacitance values ​​of the second path voltage stabilization capacitor C2 and the second detection voltage stabilization capacitor CY2 are equal, and the resistance value of the first resistor R1 is equal to the resistance value of the second resistor R2.

[0097] The sampling unit 12 includes a voltage follower 121. The positive phase terminal in1 of the voltage follower 121 is connected to the sampling node Q, and the negative phase terminal in2 of the voltage follower 121 is connected to the output terminal out of the voltage follower 121. The output terminal out receives a first detection voltage U from the sampling node Q. LE and connected to a signal processing unit 13 for collecting the second detection voltage UNE, and the first detection voltage U LE and the second detection voltage U NE This is transmitted to the signal processing unit 13.

[0098] The signal processing unit 13 includes a clamping circuit 131 and a digital signal processor (DSP) 132. The clamping circuit 131 is connected between the output terminal out of the voltage follower 121 and the digital signal processor 132, and the first detection voltage U LE and the second detection voltage U NE It is used to clamp the received voltage value of the first detected voltage U within a preset range. The digital signal processor 132 uses the first detected voltage U LE and the second detected voltage U NE Used to compare and in digital format. First detection voltage U LE and the second detection voltage U NE If the difference is greater than a preset threshold, this indicates that a leakage fault has occurred in power supply 20.

[0099] Specifically, when the drive device 100 turns on the discharge function and supplies power to an electrical device outside the vehicle body, the power supply 20 converts DC to AC, and in the first detection circuit 111, the first detection voltage stabilizing capacitor CY1, diode D1, first resistor R1, sampling resistor Rx, and first path voltage stabilizing capacitor C1 form a detection loop between the first phase discharge path L and the second phase discharge path N. The voltage follower 121 in the sampling unit 12 receives the first detection voltage U from the sampling node Q. LE The first detected voltage U is collected. LE The first detected voltage U is transmitted to the clamping circuit 131. The clamping circuit 131 receives the first detected voltage U. LE The signal is clamped and sent to the digital signal processor 132.

[0100] In the second detection circuit 112, the second detection voltage stabilizing capacitor CY2, the second diode D2, the second resistor R2, the sampling resistor Rx, and the second path voltage stabilizing capacitor C2 form a detection loop between the second phase discharge path N and the first phase discharge path. The voltage follower 121 in the sampling unit 12 receives the second detection voltage U from the sampling node Q. NE Collect the second detection voltage U NEThe second detection voltage U is transmitted to the clamping circuit 131. The clamping circuit 131 receives the second detection voltage U. NE The first detected voltage U is clamped and sent to the digital signal processor 132. The digital signal processor 132 receives the first detected voltage U LE and the second detected voltage U NE The first detected voltage U is compared in digital format. LE and the second detected voltage U NE If the difference between the two values ​​is greater than a preset threshold, this indicates that a leakage fault has occurred in power supply 20.

[0101] The frequency of the AC output from power supply 20 is f AC =50Hz, and the impedance of the first voltage stabilization capacitor C1 is R C1 = 1 / (2π*f AC *C C1 ) and the impedance of the first detection voltage stabilization capacitor CY1 is R CY1 = 1 / (2π*f AC *C CY1 ) and the impedance of the second path voltage stabilization capacitor C2 is R C2 = 1 / (2π*f AC *C C2 ) and the impedance of the second detection voltage stabilization capacitor CY2 is R CY2 = 1 / (2π*f AC *C CY2 )

[0102] U L =R X / (R CY1 +R1+R X )*U LE U N = R X / (R CY2 +R2+R X )*U NE That is the case.

[0103] JPEG0007870397000005.jpg37162

[0104] U LNThis is the differential mode voltage between the first phase discharge path L and the second phase discharge path N.

[0105] The "GB / T18384-2020 Electric Vehicles Safety Requirements" specifies requirements for leakage current in new energy electric vehicles, stating that at maximum operating voltage, the minimum insulation resistance of the AC circuit should be greater than 500 Ω / V, and the effective value of the maximum operating voltage is 220 V. The national standard states that the insulation resistance on the AC side is

number

number

[0106] If a leakage fault occurs at one end of the first phase discharge path L to ground and / or at one end of the second phase discharge path N to ground, the first detection voltage U decreases as the insulation resistance RL of the first phase discharge path L to device ground decreases. LE |U| decreases, and therefore the voltage UL at the L terminal of the first phase discharge path decreases. At this time, a large voltage difference is created between the voltage UL at the L terminal of the first phase discharge path and the voltage UN at the N terminal of the second phase discharge path, and the deviation value of the common-mode voltage reaches the voltage threshold M, i.e., |U| LE -U NEWhen |>M is detected, a leakage fault is reported and the discharge is terminated. The specific common-mode voltage difference threshold M needs to be matched based on the equivalent capacitance of the AC port when the vehicle is discharging, i.e., the equivalent capacitance of the first path voltage stabilizing capacitor C1 and the second path voltage stabilizing capacitor C2 when the vehicle is discharging. A 110kΩ resistor is connected in parallel between the first phase discharge path L or the second phase discharge path N of the drive device 100 and the vehicle body, and the common-mode voltage difference threshold M is matched by software.

[0107] The device 10 for detecting leakage current provided in this embodiment can ensure detection accuracy while making the insulation resistance between the AC ports of the power supply 20, i.e., between the first phase discharge path L and the second phase discharge path N, 20 MΩ or more.

[0108] By detecting leakage current in the drive device by collecting the common-mode voltage of the power supply discharge loop, it avoids the need to directly install a device to detect leakage current between the high-voltage circuit of the drive device and the vehicle body, improving the overall insulation performance of the vehicle and meeting industry-standard vehicle safety requirements. At the same time, when there is no leakage current fault in the power supply discharge loop, the device for detecting leakage current is in a low-power state, thereby reducing power consumption. The overall power consumption of the device for detecting leakage current is low and the structure is simple, thereby significantly reducing usage and manufacturing costs.

[0109] Referring to Figure 9, Figure 9 is a flowchart of a method for detecting leakage current provided by a sixth embodiment of the present disclosure. As shown in Figure 9, the method for detecting leakage current can be applied to the aforementioned leakage current detection device and drive device. The specific steps are as follows:

[0110] In S101, when the power supply is discharged positively through the first phase discharge path, the first detection circuit is activated, and the sampling unit is controlled to collect a first detection voltage from the first detection circuit.

[0111] When the power supply 20 converts DC to AC to supply power to electrical devices outside the vehicle, when the first phase discharge path L is activated, the first detection circuit 111 is activated, and the sampling unit 12 receives the first detection voltage U from the sampling node in the first detection circuit 111. LE It is possible to collect the first detection voltage U LE This is the common-mode voltage between the first phase discharge path L and the device ground E.

[0112] In S102, when the power supply is discharged positively through the second phase discharge path, the second detection circuit is activated, and the sampling unit is controlled to collect a second detection voltage from the second detection circuit.

[0113] When the second phase discharge path N is activated, the second detection circuit 112 is activated, and the sampling unit 12 receives the second detection voltage U from the sampling node in the second detection circuit 112. NE It is possible to collect the second detection voltage U NE This is the common-mode voltage between the second phase discharge path N and the device ground E.

[0114] In S103, the voltage difference between the first detected voltage and the second detected voltage is compared with the threshold voltage. If the voltage difference is greater than the threshold voltage, it is determined that a leakage fault has occurred in the power supply.

[0115] The signal processing unit 13 receives the first detected voltage U LE and the second detection voltage U NE This is compared with an internally preset threshold voltage. The first detected voltage U LE and the second detected voltage U NE If the voltage difference between the two points is greater than the threshold voltage, this indicates that a leakage fault has occurred in the first phase discharge path L or the second phase discharge path N.

[0116] It should be understood that the application of this disclosure is not limited to the examples given above. Those skilled in the art may make improvements or modifications based on the above description. All such improvements and modifications should fall within the scope of protection of the claims attached to this disclosure.

Claims

1. A detection unit (11) wherein the detection unit (11) is separately connected to a first phase discharge path and a second phase discharge path, the first phase discharge path and the second phase discharge path are configured to connect to a power supply (20) and transmit electricity output when the power supply (20) is discharged, and the detection unit (11) is configured to establish a detection loop of the first phase discharge path and the second phase discharge path when the power supply (20) is discharged, A sampling unit (12) is electrically connected to the detection unit (11) and configured to separately collect a first detection voltage of the first phase discharge path and a second detection voltage of the second phase discharge path from the detection loop, A signal processing unit (13) is connected to the sampling unit (12) and is configured to asynchronously receive the first detection voltage and the second detection voltage from the sampling unit (12) and to determine the leakage characteristics of the power supply (20) based on the first detection voltage and the second detection voltage. It is equipped with, The detection unit (11) comprises a first detection circuit (111) and a second detection circuit (112), The first detection circuit (111) is connected between the first phase discharge path and the low-voltage ground to form the detection loop. The second detection circuit (112) is connected between the second phase discharge path and the low-voltage ground to form the detection loop. The sampling unit (12) is configured to collect the first detection voltage from the first detection circuit (111) and the second detection voltage from the second detection circuit (112), The first detection circuit (111) comprises a first detection voltage stabilization module (111B), a first unidirectional conduction module (111D), and a sampling module (111E), wherein the first detection voltage stabilization module (111B), the first unidirectional conduction module (111D), and the sampling module (111E) are sequentially connected in series between the first phase discharge path and the low voltage ground to form the detection loop. Device (10) for detecting leakage current, wherein the second detection circuit (112) comprises a second detection voltage stabilization module (112B) and a second unidirectional conduction module (112D), and the second detection voltage stabilization module (112B), the second unidirectional conduction module (112D), and the sampling module (111E) are sequentially connected in series between the second phase discharge path and the low-voltage ground to form the detection loop.

2. The first detection voltage stabilization module (111B) comprises a first switch, the first unidirectional conduction module (111D) comprises a first diode, and the sampling module (111E) comprises a first resistor, a sampling node, and a sampling resistor. The first switch, the first diode, the first resistor, and the sampling resistor are sequentially connected in series between the first phase discharge path and the low-voltage ground to form the detection loop, the anode of the first diode is connected to the first switch, the cathode of the first diode is connected to the first resistor, and the sampling node is the node between the first resistor and the sampling resistor. The second detection voltage stabilization module (112B) comprises a second switch, the second unidirectional conduction module (112D) comprises a second diode, and the second switch, the second diode, the first resistor, and the sampling resistor are sequentially connected in series between the second phase discharge path and the low voltage ground to form the detection loop, the anode of the second diode is connected to the second switch, and the cathode of the second diode is connected to the first resistor, The device (10) for detecting leakage current according to claim 1, wherein the sampling unit (12) collects the first detection voltage and the second detection voltage from the sampling node.

3. The first detection voltage stabilization module (111B) comprises a first detection voltage stabilization capacitor, the first unidirectional conduction module (111D) comprises a first diode, and the sampling module (111E) comprises a first resistor, a sampling node, and a sampling resistor. The first detection voltage stabilizing capacitor, the first diode, the first resistor, and the sampling resistor are sequentially connected in series between the first phase discharge path and the low voltage ground to form the detection loop, the anode of the first diode is connected to the first detection voltage stabilizing capacitor, the cathode of the first diode is connected to the first resistor, and the sampling node is the node between the first resistor and the sampling resistor. The second detection voltage stabilization module (112B) comprises a second detection voltage stabilization capacitor, the second unidirectional conduction module (112D) comprises a second diode, and the second detection voltage stabilization capacitor, the second diode, the first resistor, and the sampling resistor are sequentially connected in series between the second phase discharge path and the low voltage ground to form the detection loop, the anode of the second diode is connected to the second detection voltage stabilization capacitor, and the cathode of the second diode is connected to the first resistor, The device (10) for detecting leakage current according to claim 1, wherein the sampling unit (12) collects the first detection voltage and the second detection voltage from the sampling node.

4. The sampling unit (12) comprises a differential operational amplifier (122), a second resistor, a third resistor, and a third capacitor. The positive phase terminal of the differential operational amplifier (122) is connected to the sampling node and is configured to collect the first detection voltage and the second detection voltage from the sampling node. The device (10) for detecting leakage current according to claim 2, wherein the second resistor and the third capacitor are connected in series between the reverse-phase terminal of the differential operational amplifier (122) and device ground, the reverse-phase terminal of the differential operational amplifier (122) is connected to the output terminal of the differential operational amplifier (122) via the third resistor, and the first detection voltage and the second detection voltage are increased or decreased according to a preset ratio, and the first detection voltage and the second detection voltage are output from the output terminal of the differential operational amplifier (122).

5. A detection unit (11) wherein the detection unit (11) is separately connected to a first phase discharge path and a second phase discharge path, the first phase discharge path and the second phase discharge path are configured to connect to a power supply (20) and to transmit electricity output when the power supply (20) is discharged, and the detection unit (11) is configured to establish a detection loop of the first phase discharge path and the second phase discharge path when the power supply (20) is discharged, A sampling unit (12) is electrically connected to the detection unit (11) and configured to separately collect a first detection voltage of the first phase discharge path and a second detection voltage of the second phase discharge path from the detection loop, A signal processing unit (13) is connected to the sampling unit (12) and is configured to asynchronously receive the first detection voltage and the second detection voltage from the sampling unit (12) and to determine the leakage characteristics of the power supply (20) based on the first detection voltage and the second detection voltage. It is equipped with, The detection unit (11) is further connected to a third phase discharge path, and the power supply (20) is a three-phase AC power supply that outputs currents having equal amplitude, the same frequency, and the same phase difference through the first phase discharge path, the second phase discharge path, and the third phase discharge path, and is a device (10) for detecting leakage current.

6. A detection unit (11) wherein the detection unit (11) is separately connected to a first phase discharge path and a second phase discharge path, the first phase discharge path and the second phase discharge path are configured to connect to a power supply (20) and transmit electricity output when the power supply (20) is discharged, and the detection unit (11) is configured to establish a detection loop of the first phase discharge path and the second phase discharge path when the power supply (20) is discharged, A sampling unit (12) is electrically connected to the detection unit (11) and configured to separately collect a first detection voltage of the first phase discharge path and a second detection voltage of the second phase discharge path from the detection loop, A signal processing unit (13) is connected to the sampling unit (12) and is configured to asynchronously receive the first detection voltage and the second detection voltage from the sampling unit (12) and to determine the leakage characteristics of the power supply (20) based on the first detection voltage and the second detection voltage. It is equipped with, The detection unit (11) comprises a first detection circuit (111) and a second detection circuit (112), The first detection circuit (111) is connected between the first phase discharge path and the device ground, and is connected to the second phase discharge path by the device ground to form the detection loop. The second detection circuit (112) is connected between the second phase discharge path and the device ground, and is connected to the first phase discharge path via the device ground to form the detection loop. The first detection circuit (111) comprises a first detection voltage stabilization module (111B), a first path voltage stabilization module (111A), a first voltage division module (111C), and a sampling module (111E), wherein the first detection voltage stabilization module (111B), the first voltage division module (111C), and the sampling module (111E) are sequentially connected in series between the first phase discharge path and the device ground, and the first path voltage stabilization module (111A) is simultaneously connected between the second phase discharge path and the device ground to form the detection loop. The second detection circuit (112) comprises a second detection voltage stabilization module (112B), a second path voltage stabilization module (112A), and a second voltage division module (112C), wherein the second detection voltage stabilization module (112B), the second voltage division module (112C), and the sampling module (111E) are sequentially connected in series between the second phase discharge path and the device ground, and the second path voltage stabilization module (112A) is simultaneously connected between the first phase discharge path and the device ground to form the detection loop. A device (10) for detecting electrical leakage.

7. The first detection voltage stabilization module (111B) comprises a first switch, the first voltage division module (111C) comprises a first diode and a first resistor, the sampling module (111E) comprises a sampling resistor and a sampling node, the first path voltage stabilization module (111A) comprises a first path voltage stabilization capacitor, the first switch, the first diode, the first resistor, and the sampling resistor are sequentially connected in series between the first phase discharge path and the device ground, the anode of the first diode is connected to the first switch, the cathode of the first diode is connected to the first resistor, the sampling node is the node between the first resistor and the sampling resistor, and the first path voltage stabilization capacitor is simultaneously connected between the device ground and the second phase discharge path to form the detection loop. The second detection voltage stabilization module (112B) comprises a second switch, the second voltage division module (112C) comprises a second diode and a second resistor, the second path voltage stabilization module (112A) comprises a second path voltage stabilization capacitor, the second switch, the second diode, the second resistor, and the sampling resistor are sequentially connected in series between the second phase discharge path and the device ground, the anode of the second diode is connected to the second switch, the cathode of the second diode is connected to the second resistor, and the second path voltage stabilization capacitor is simultaneously connected between the device ground and the first phase discharge path to form the detection loop. The device (10) for detecting leakage current according to claim 6, wherein the sampling unit (12) is configured to collect the first detection voltage and the second detection voltage from the sampling node.

8. The first detection voltage stabilization module (111B) comprises a first detection voltage stabilization capacitor, the first path voltage stabilization module (111A) comprises a first path voltage stabilization capacitor, the first voltage division module (111C) comprises a first diode and a first resistor, the sampling module (111E) comprises a sampling node and a sampling resistor, the first detection voltage stabilization capacitor, the first diode, the first resistor, and the sampling resistor are sequentially connected in series between the first phase discharge path and the device ground, the anode of the first diode is connected to the first detection voltage stabilization capacitor, the cathode of the first diode is connected to the first resistor, the sampling node is the node between the first resistor and the sampling resistor, and the first path voltage stabilization capacitor is simultaneously connected between the device ground and the second phase discharge path to form the detection loop. The second detection voltage stabilization module (112B) comprises a second detection voltage stabilization capacitor, the second voltage division module (112C) comprises a second diode and a second resistor, the second path voltage stabilization module (112A) comprises a second path voltage stabilization capacitor, the second detection voltage stabilization capacitor, the second diode, the second resistor, and the sampling resistor are sequentially connected in series between the second phase discharge path and the device ground, the anode of the second diode is connected to the second detection voltage stabilization capacitor, the cathode of the second diode is connected to the second resistor, and the second path voltage stabilization capacitor is simultaneously connected between the device ground and the first phase discharge path to form the detection loop. The device (10) for detecting leakage current according to claim 6, wherein the sampling unit (12) is configured to collect the first detection voltage and the second detection voltage from the sampling node.

9. Device (10) for detecting leakage current according to claim 7, wherein the sampling unit (12) comprises a voltage follower (121), the positive phase terminal of the voltage follower (121) is connected to the sampling node and configured to collect the first detection voltage and the second detection voltage from the sampling node, the negative phase terminal of the voltage follower is connected to the output terminal of the voltage follower and configured to increase or decrease the collected first detection voltage and the second detection voltage according to a preset ratio and to output the collected first detection voltage and the second detection voltage from the output terminal of the voltage follower (121).

10. The signal processing unit (13) comprises a clamping circuit (131) and a digital signal processor (132), wherein the clamping circuit (131) is connected to the sampling unit (12) and the digital signal processor (132), and is configured to clamp the first detection voltage and the second detection voltage received from the sampling unit (12) to a preset voltage range, and to output the first detection voltage and the second detection voltage to the digital signal processor (132), The device (10) for detecting leakage current according to claim 1, wherein the digital signal processor (132) receives the first detection voltage and the second detection voltage, and determines the leakage current characteristics of the power supply (20) based on the first detection voltage and the second detection voltage.

11. A method for detecting an electrical leakage, wherein the method is applied to the device (10) for detecting the electrical leakage described in claim 1 or 6. When the power supply (20) is positively discharged through the first phase discharge path, the first detection circuit (111) is made conductive, and the sampling unit (12) is controlled to collect the first detection voltage from the first detection circuit (111) (S101), When the power supply (20) is positively discharged through the second phase discharge path, the second detection circuit (112) is activated, and the sampling unit (12) is controlled to collect the second detection voltage from the second detection circuit (112) (S102), The voltage difference between the first detection voltage and the second detection voltage is compared with a threshold voltage, and if the voltage difference is greater than the threshold voltage, it is determined that a leakage fault has occurred in the power supply (S103). A method for detecting electrical leakage, including the detection of ground faults.

12. A vehicle comprising a power supply (20) and a device (10) for detecting leakage current according to any one of claims 1 to 11, wherein the power supply (20) is connected to a first phase discharge path and a second phase discharge path, discharges through the first phase discharge path and the second phase discharge path to output an alternating current, and is configured to detect the leakage current, and the device (10) comprises a detection assembly and a sampling assembly, and is configured to detect leakage current with respect to the first phase discharge path and the second phase discharge path when the power supply (20) is discharged.

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