Insulation detection device and method, charging pile

Abstract

The application discloses an insulation detection device and method, and a charging pile. The device comprises a first sampling unit and a second sampling unit arranged on a power supply circuit, a first signal processing module connected with the first sampling unit, a second signal processing module connected with the second sampling unit, a detection module connected with the first signal processing module and the second signal processing module, and a signal source and a reference source. The signal source is used for injecting a voltage into the power supply ground wire. The reference source is used for outputting a fixed voltage. The first signal processing module is used for acquiring a first sampling voltage on the first sampling unit and a corresponding first amplification voltage. The second signal processing module is used for acquiring a second sampling voltage on the second sampling unit and a corresponding second amplification voltage. The detection module determines the insulation of the power supply circuit according to the first sampling voltage and the corresponding first amplification voltage, and the second sampling voltage and the corresponding second amplification voltage. By using the application, high-precision and real-time insulation detection can be realized on the high-voltage power supply circuit, and the power supply safety is ensured.

Description

Technical Field

[0001] This invention relates to the field of circuits, and more specifically to an insulation testing device and method, and a charging pile. Background Technology

[0002] With the rapid popularization of electric vehicles, people have increasingly higher requirements for safe energy transmission. Charging stations are used outdoors for extended periods, and with alternating high and low temperatures, the insulation performance of these stations may deteriorate over time. When the insulation performance drops to a certain level, leakage current will occur during use. This leakage current can flow through a person's body to the ground, posing a danger to personal safety. Therefore, during the charging process of new energy vehicles, it is necessary to monitor the impedance value of the transmission system to the ground in real time. When low impedance is detected, charging should be disconnected promptly to protect personal safety. Summary of the Invention

[0003] This invention provides an insulation testing device and method, as well as a charging pile, to achieve real-time insulation testing of the power supply circuit and improve the accuracy of insulation testing.

[0004] Therefore, the present invention provides the following technical solution:

[0005] On one hand, the present invention provides an insulation detection device, comprising: a first sampling unit and a second sampling unit disposed on a power supply circuit, a first signal processing module, a second signal processing module, a detection module, a signal source and a reference source; the negative terminal of the signal source and the negative terminal of the reference source are connected to signal ground, the positive terminal of the signal source is connected to the power supply ground line, and the positive terminal of the reference source is connected to the first sampling unit and the second sampling unit respectively;

[0006] The signal source is used to inject voltage into the power supply ground wire;

[0007] The reference source is used to output a fixed voltage;

[0008] The first signal processing module is used to acquire the first sampling voltage U1 and the corresponding first amplification voltage U2 on the first sampling unit;

[0009] The second signal processing module is used to acquire the second sampling voltage U3 and the corresponding second amplification voltage U4 on the second sampling unit;

[0010] The detection module is used to determine a first voltage from a first sampling voltage U1 and a corresponding first amplified voltage U2 on the first sampling unit, and to determine a second voltage from a second sampling voltage U3 and a corresponding second amplified voltage U4 on the second sampling unit, and to determine the insulation of the power supply circuit based on the first voltage and the second voltage.

[0011] Optionally, the first signal processing module comprises:

[0012] a first voltage acquisition unit, configured to acquire a first sampling voltage U1 on the first sampling unit and output the first sampling voltage U1 to the detection module;

[0013] a first voltage amplification unit, configured to amplify the first sampling voltage U1 and output a first amplified voltage U2 to the detection module;

[0014] the second signal processing module comprises:

[0015] a second voltage acquisition unit, configured to acquire a second sampling voltage U3 on the second sampling unit and output the second sampling voltage U3 to the detection module;

[0016] a second voltage amplification unit, configured to amplify the second sampling voltage U3 and output a second amplified voltage U4 to the detection module.

[0017] Optionally, the first voltage acquisition unit and the second voltage acquisition unit are voltage followers.

[0018] Optionally, the first voltage amplification unit and the second voltage amplification unit are operational amplifiers.

[0019] Optionally, the detection module is configured to calculate a ground resistance across the power supply circuit according to the first voltage and the second voltage, and determine the insulation of the power supply circuit according to the ground resistance across the power supply circuit.

[0020] Optionally, the resistance values of the first sampling unit and the second sampling unit are equal.

[0021] Optionally, the output voltage of the reference source is 0-5V.

[0022] Optionally, the signal source outputs a square wave signal.

[0023] In another aspect, the present application also provides a charging pile comprising the insulation detection device.

[0024] In another aspect, the present application also provides an insulation detection method, which is used for a power supply circuit, wherein the power supply circuit is provided with a first sampling unit and a second sampling unit, and a signal source and a reference source are mirror-connected between a power supply ground wire and the first sampling unit and the second sampling unit.

[0025] The method comprises:

[0026] When performing insulation detection, the signal source injects a voltage into the power supply ground wire of the power supply circuit.

[0027] acquire the first sampling voltage U1 and the corresponding first amplification voltage U2 on the first sampling unit, and acquire the second sampling voltage U3 and the corresponding second amplification voltage U4 on the second sampling unit;

[0028] determine a first voltage according to the first sampling voltage U1 and the corresponding first amplification voltage U2 on the first sampling unit, determine a second voltage according to the second sampling voltage U3 and the corresponding second amplification voltage U4 on the second sampling unit, and determine the insulation of the power supply loop according to the first voltage and the second voltage.

[0029] Optionally, the determining the insulation of the power supply loop according to the first voltage and the second voltage comprises:

[0030] calculating the resistance to ground at both ends of the power supply loop according to the first voltage and the second voltage;

[0031] determining the insulation of the power supply loop according to the resistance to ground at both ends of the power supply loop.

[0032] The insulation detection device and method provided by the embodiment of the present application can ensure high-precision signal acquisition and improve the precision of insulation detection in the case that the impedance of the power transmission line to the ground is unbalanced.

[0033] The charging pile provided by the embodiment of the present application integrates the above insulation detection device, and can realize high-precision detection of the insulation of the power supply loop and improve the accuracy of the detection result.

[0034] Further, the charging pile provided by the embodiment of the present application can also detect the voltage outside the gun wire of the charging gun, and better meets the requirements of various detection applications. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 is a structural schematic diagram of the insulation detection device provided by the embodiment of the present application;

[0036] Figure 2 is a specific structural schematic diagram of the insulation detection device provided by the embodiment of the present application;

[0037] Figure 3This is a flowchart of determining the voltage on the sampling unit in the insulation detection device provided in this embodiment of the invention;

[0038] Figure 4 This is a schematic diagram of the structure of the charging pile provided in an embodiment of the present invention;

[0039] Figure 5 This is a flowchart of an insulation testing method provided in an embodiment of the present invention. Detailed Implementation

[0040] To make the above-mentioned objectives, features and beneficial effects of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0041] Existing insulation testing methods include the bridge method. This method requires applying a certain voltage to the busbar during testing and closing different switches to change the impedance of the bridge arms, thus detecting the busbar's impedance to ground. Since these switches are mostly relays, long-term load switching can cause relay contacts to stick together and other faults. Furthermore, when there are problems with the impedance to ground at one or both ends of the transmission line, the voltage imbalance of the bridge arms cannot guarantee consistent sampling accuracy between the upper and lower arms, affecting the insulation testing accuracy.

[0042] Since most of the switches used in the existing bridge method for insulation testing are relays, long-term load switching can easily cause relay contacts to stick together and other faults. Moreover, when there are problems with the impedance to ground at one or both ends of the transmission line, the voltage of the bridge arms is unbalanced, and it is impossible to ensure that the sampling accuracy of the upper and lower bridge arms is consistent, which ultimately leads to poor insulation testing accuracy.

[0043] To address this issue, this invention provides an insulation testing device and method. The method addresses the problem of large voltage fluctuations across the sampling unit caused by the different impedance values ​​(R+ and R-) of the positive and negative busbars of the power transmission line to ground (e.g., due to a single fault or both faults in the positive and negative busbars), which affects the accuracy of insulation testing. By separately acquiring the sampling voltage and corresponding amplified voltage on the sampling unit, the range of voltage values ​​across the sampling unit is first determined, and then an appropriate sampling accuracy is used to acquire the sampling voltage, thereby improving the insulation testing accuracy of the power supply circuit.

[0044] like Figure 1 As shown, Figure 1 This is a schematic diagram of an insulation detection device provided in an embodiment of the present invention.

[0045] This insulation testing device is used in DC power supply circuits to detect the insulation of the DC power supply circuit. Figure 1DC+ and DC- in the power loop are two output ports, such as the positive and negative ends of the power module output; DC+ OUT and DC- OUT are two output ports of the power supply loop, which are used to connect the powered end device and supply power to the powered end device. The powered end device can be an electric vehicle or the like. The power supply switch is usually arranged between the power loop and the power supply loop. After the power supply switch is turned on, the power loop outputs voltage to the power supply loop, and the power supply loop supplies power to the outside, such as charging the electric vehicle.

[0046] Referring to Figure 1 The insulation detection device of the embodiment includes a first sampling unit r1 and a second sampling unit r2 arranged on the power supply loop, a first signal processing module 11 connected with the first sampling unit r1, a second signal processing module 12 connected with the second sampling unit r2, a detection module 20 connected with the first signal processing module 11 and the second signal processing module 12, and a signal source Us and a reference source Uref. The negative end of the signal source Us and the negative end of the reference source Uref are connected with the signal ground, the positive end of the signal source Us is connected with the power ground PE, and the positive end of the reference source Uref is connected with the first sampling unit r1 and the second sampling unit r2 respectively. The power ground PE (also referred to as the lightning conductor) is a wire used to introduce current into the ground. When the electrical equipment leaks or the voltage is too high, the current enters the ground through the power ground.

[0047] The first sampling unit r1 and the second sampling unit r2 can be realized by resistance or current transformer, and for the convenience of description, the realization by resistance is taken as an example in the following description. Generally, the sampling resistance can be selected as a resistance with a small resistance value, such as 100Ω-1kΩ.

[0048] Further, in order to avoid excessive current, the voltage dividing resistors R1 and R2 can be connected in series on the power supply loop, as shown in Figure 1 The upper bridge arm includes the first voltage dividing resistor R1 and the first sampling unit r1 connected in series, and the lower bridge arm includes the second voltage dividing resistor R2 and the second sampling unit r2 connected in series. The resistance values of the first sampling unit r1 and the second sampling unit r2 can be the same for the convenience of calculation, and the first voltage dividing resistor R1 and the second voltage dividing resistor R2 can be the same or different, such as a resistance greater than or equal to 500kΩ, which is not limited in the embodiment of the application.

[0049] It should be noted that Figure 1 The position relationship between the voltage dividing resistors and the sampling units in the above embodiment is only described schematically, and in some embodiments, the first voltage dividing resistor R1 and the second voltage dividing resistor R2 can also be multiple, such as a resistance array composed of series and / or parallel connection, which is not limited in the embodiment of the application.

[0050] Figure 1 In the embodiment shown, the reference source Uref and the signal source Us are connected in mirror, that is, the negative terminal of the reference source Uref is connected to the negative terminal of the signal source Us and is connected to the signal ground, and the signal source Us is used to inject a voltage to the power supply ground PE; the reference source Uref is used to output a fixed voltage.

[0051] In some embodiments, the signal source Us can be a signal generator, such as a periodic square wave signal generator, and the amplitude of the square wave signal can be less than or equal to 36V, such as ±12V to ±24V in a specific application. The reference source Uref outputs a fixed voltage U R , for example, U R may be 0-5V.

[0052] The first signal processing module 11 is used to obtain the first sampling voltage U1 on the first sampling unit r1 and the corresponding first amplification voltage U2, and output to the ports ADC1 and ADC2 of the detection module 20. The second signal processing module 12 has a similar function as the first signal processing module 11, and is used to obtain the second sampling voltage U3 on the second sampling unit and the corresponding second amplification voltage U4, and output to the ports ADC3 and ADC4 of the detection module 20.

[0053] The detection module 20 is used to determine the first voltage U1' according to the first sampling voltage U1 on the first sampling unit r1 and the corresponding first amplification voltage U2, determine the second voltage U2' according to the second sampling voltage U3 on the second sampling unit r2 and the corresponding second amplification voltage U4, and determine the insulation of the power supply loop according to the first voltage U1' and the second voltage U2'. The first voltage U1' is the actual voltage across the first sampling unit r1, and the second voltage U2' is the actual voltage across the second sampling unit r2.

[0054] Among them, the first voltage U1' is to judge the size of the first sampling voltage U1 and the first amplification voltage U2, determine the voltage range of the sampling voltage on the first sampling unit r1, and then select the sampling mode suitable for the voltage range to obtain the voltage on the first sampling unit r1, that is, according to the judgment result, select the voltage based on the port ADC1 as the voltage on the first sampling unit r1, or select the voltage based on the port ADC2 to calculate the voltage on the first sampling unit r1.

[0055] Similarly, the second voltage U2' is the voltage on the second sampling unit r2 determined after judging the size of the second sampling voltage U3 and the second amplification voltage U4.

[0056] Specifically, the voltage across the sampling unit can be determined by comparing the amplified voltage value with the maximum range value. For example, if the maximum range value (saturation voltage) of ADC2 (amplified voltage value) is 5V, and the detected voltage of ADC2 is 5V, it is considered that the voltage of the first sampling unit is too large, and the amplified voltage may have exceeded the measurement range. Therefore, the first sampling voltage U1 obtained by ADC1 can be used as the first voltage for subsequent insulation calculation.

[0057] Understandably, due to the different impedance values ​​R+ and R- of the positive and negative buses of the power transmission line to ground, and the possibility of single or both bus faults, the voltages across the first sampling unit r1 and the second sampling unit r2 may differ significantly, even to the point of being on different orders of magnitude. For example, the voltage across the first sampling unit r1 might be in the microvolt range, while the voltage across the second sampling unit r2 might be in the volt range. If the same sampling method (i.e., the same sampling precision) is used to obtain the sampling voltages of the first sampling unit r1 and the second sampling unit r2, the sampling values ​​may be inaccurate. In the insulation detection device of this embodiment, the voltage values ​​of the first sampling unit r1 and the second sampling unit r2 are obtained through two sampling methods: a following method and an amplification method. The following method yields the voltage value itself, while the amplification method yields a voltage value amplified by a certain ratio. The following and amplified voltage values ​​are then compared. If the voltage across the sampling unit is large, it can be directly sampled to obtain a more accurate voltage (i.e., the following method is used). If the voltage across the sampling unit is low, it can be amplified before sampling to obtain a high-precision sampling voltage. Understandably, when the voltage across the sampling unit is low, direct sampling will not yield a precise voltage value due to sampling range limitations. For example, with a voltage of 158 millivolts, the voltage range accuracy of the follow-up method is insufficient, and the obtained voltage may only be 0.15V. Therefore, the insulation detection device of this embodiment can improve voltage sampling accuracy, thereby improving the accuracy of insulation detection based on the sampling voltage.

[0058] The ground resistances R+ and R- at both ends of the power supply circuit can be calculated based on the first voltage U1' and the second voltage U2', and the insulation of the power supply circuit can be determined based on the ground resistances at both ends of the power supply circuit.

[0059] The method for determining the first voltage U1' and the second voltage U2' will be explained in detail later.

[0060] The following section will first explain in detail the principle of calculating the ground resistances R+ and R- at both ends of the power supply circuit based on the first voltage U1' and the second voltage U2'.

[0061] In the insulation detection, the reference source Uref outputs a fixed voltage U R , and the signal source Us outputs different voltages U1 and U2 to change the voltage of the circuit and perform real-time insulation detection. The insulation detection principle is as follows:

[0062] When the signal source Us inputs the voltage U1 to the power ground PE, the voltage across the first sampling unit r1 is U r1 , and the voltage across the second sampling unit r2 is U r2 According to the Kirchhoff's current law, that is, at any node in the circuit, the sum of the currents flowing into the node at any time is equal to the sum of the currents flowing out of the node, formula (1) can be obtained:

[0063]

[0064] Similarly, when the signal source Us inputs the voltage U2 to the power ground PE, the voltage across the first sampling unit r1 is U r3 , and the voltage across the second sampling unit r2 is U r4 According to the Kirchhoff's current law, formula (2) can be obtained:

[0065]

[0066] Wherein, U r1 and U r2 are the first voltage U1' and the second voltage U2' obtained by the above sampling method when the signal source Us outputs the voltage U1; U r3 and U r4 are the first voltage U1' and the second voltage U2' obtained by the above sampling method when the signal source Us outputs the voltage U2.

[0067] Solving the above formulas (1) and (2) together, the resistances R+ and R- of the output ends DC+_OUT and DC-_OUT of the power supply circuit to the power ground PE, that is, the resistances of the output ends DC+ and DC- of the power circuit to the power ground PE, can be calculated. According to the resistance values of R+ and R-, the insulation performance of the power supply circuit can be determined.

[0068] For example, when the insulation detection device provided by the embodiment of the present application is applied to a charging pile, the insulation performance of the charging pile can be determined according to the real-time charging voltage U of the vehicle and the above resistances R+ and R- calculated by detection, and further, whether the vehicle continues to charge and other operations can be controlled.

[0069] For example, in some standards, the following judgments and operations can be made:

[0070] If and The vehicle can be normally charged;

[0071] If Or It is indicated that the insulation performance in the charging pile is reduced, such as the charging pile insulation alarm can be performed;

[0072] If Or Determine that the charging pile insulation is problematic, and prohibit charging.

[0073] As Figure 2 Fig. 1 is a specific structure schematic diagram of the insulation detection device provided by the embodiment of the present application.

[0074] In this embodiment, power switches K1 and K2 are arranged between the power circuit and the power supply circuit. After the power switches K1 and K2 are closed, the power circuit outputs a voltage to the power supply circuit, and the power supply circuit supplies power to the outside, such as charging an electric vehicle.

[0075] In this embodiment, the first signal processing module includes a first voltage acquisition unit IC_A and a first voltage amplification unit IC_B. Wherein: the first voltage acquisition unit IC_A is used to acquire the first sampling voltage U1 on the first sampling unit r1, and output the first sampling voltage U1 to the detection module 20; the first voltage amplification unit IC_B is used to amplify the first sampling voltage U1, and output the first amplified voltage U2 to the detection module 20.

[0076] Similarly, the second signal processing module includes a second voltage acquisition unit IC_C and a second voltage amplification unit IC_D. Wherein: the second voltage acquisition unit IC_C is used to acquire the second sampling voltage U3 on the second sampling unit r2, and output the second sampling voltage U3 to the detection module 20; the second voltage amplification unit IC_D is used to amplify the second sampling voltage U3, and output the second amplified voltage U4 to the detection module 20.

[0077] The first voltage acquisition unit IC_A and the second voltage acquisition unit IC_C can be implemented by using a voltage follower.

[0078] The first voltage amplification unit IC_B and the second voltage amplification unit IC_D can be implemented by using an operational amplifier. As Figure 2 Fig. 2 shows that the first voltage amplification unit IC_B realizes amplification of the input voltage, i.e. the first sampling voltage U1, by using the voltage dividing resistors R3 and R4; the second voltage amplification unit IC_D realizes amplification of the input voltage, i.e. the second sampling voltage U2, by using the voltage dividing resistors R5 and R6.

[0079] In this embodiment, the voltage across the first sampling unit r1 is output to port ADC1 of the detection module 20 via the first voltage acquisition unit IC_A in a voltage follower manner, and via the first voltage amplification unit IC_B, after being amplified by resistors R3 and R4, it is output to port ADC2 of the detection module 20.

[0080] The detection module 20 can simultaneously acquire the voltage values ​​of port ADC1 and port ADC2. By judging the current voltage values ​​of port ADC1 and port ADC2, the voltage range across the first sampling unit r1 is determined, and then the electrical terminals across the first sampling unit r1 are selected based on either the voltage value of port ADC1 or port ADC2 to obtain the first voltage U1'.

[0081] Accordingly, based on the above principle, the detection module 20 determines the voltage value across the first sampling unit r1, i.e., the first voltage U1' mentioned above, in one process as follows: Figure 3 As shown. U ADC1 and U ADC2

[0082] In step 301, the voltage U of ports ADC1 and ADC2 is acquired. ADC1 and U ADC2 .

[0083] In step 302, determine U ADC2 Whether the voltage value is equal to the set value, which can be determined by the amplifier circuit (i.e., Figure 2 The setting value is determined by the saturation voltage of the first voltage amplification unit (IC_B). For example, if the saturation voltage of the amplification circuit is 5V, then the setting value is 5V.

[0084] If so, it indicates that the voltage across the first sampling unit r1 is relatively large, causing saturation in the amplifier circuit. Since the first sampling unit r1 is a relatively large resistor, the voltage signal across it is strong. In this case, a follower circuit (i.e., ...) can be used. Figure 2 If the voltage output by the first voltage acquisition unit (IC_A) is used for calculation, proceed to step 303; otherwise, it indicates that the voltage across the first sampling unit r1 is small. In this case, the voltage output by the amplifier circuit can be used for calculation to obtain a more accurate sampling voltage, proceed to step 304.

[0085] It should be noted that the amplification factor of the amplifier circuit can be selected according to the saturation voltage and detection accuracy of the amplifier circuit. For example, if the accuracy requirement of the sampling voltage is (1uV~1V), the amplification factor can be set to 6~10.

[0086] Step 303: Determine the voltage value of the first sampling unit r1 as U. ADC1 -U2.

[0087] Step 304, the voltage value of the first sampling unit r1 is determined as:

[0088]

[0089] Similarly, the voltage across the second sampling unit r2 is transmitted to the port ADC3 of the detection module 20 through the second voltage acquisition unit IC_C and the voltage follower, and is transmitted to the port ADC4 of the detection module 20 through the second voltage amplification unit IC_D and the resistors R5 and R6. The detection module 20 can acquire the voltage values of the port ADC3 and the port ADC4 at the same time. By judging the voltage values of the port ADC3 and the port ADC4, it is determined whether the voltage range of the second sampling unit r2 is the first range or the second range. If it is determined that the voltage range is the first range, it indicates that the voltage signal across the second sampling unit r2 is weak at this time, and the voltage value of the second sampling unit r2 needs to be collected through the amplification circuit of the second voltage amplification unit IC_D. If it is determined that the voltage range is the second range, it indicates that the voltage signal across the second sampling unit r2 is strong at this time, and the voltage value of the second sampling unit r2 can be collected through the follower circuit of the second voltage acquisition unit IC_C.

[0090] The voltage collection of the second sampling unit r2 and the voltage collection of the first sampling unit r1 are the same, and the voltage range judgment logic is the same, which will not be described here.

[0091] By injecting different voltages through the signal source Us, the voltage values across the sampling units r1 and r2 can be accurately collected, and the impedance of any one of the power transmission lines DC+ and DC- to the ground can be accurately calculated.

[0092] The signal source Us in the above embodiments can be a square wave signal generator, which outputs a square wave signal with a certain frequency and amplitude. The amplitude of the square wave signal can be less than or equal to 36V, for example, a square wave signal with ±24V can be output.

[0093] Further, the insulation detection device provided by the embodiment of the application can also detect the voltage outside the gun wire, i.e., the voltage outside the power switches K1 and K2, to meet the application requirements of some scenes.

[0094] Specifically, the auxiliary switch S1 is not closed, the signal source Us does not inject voltage, the voltage across the first sampling unit r1 is Ur5, the voltage across the second sampling resistor r2 is Ur6, and the voltage outside the gun wire U K1K2 The calculation formula of the voltage outside the gun wire U is as follows:

[0095]

[0096] The insulation detection device provided by the embodiment of the present application can ensure that high-precision signal acquisition is realized and the precision of insulation detection is improved in the case that the impedance of the power transmission line to the ground is unbalanced.

[0097] Correspondingly, the embodiment of the present application further provides a charging pile, as shown in the figure, the charging pile 400 comprises the above-mentioned insulation detection device 100. Figure 5

[0098] By using the charging pile, real-time and high-precision insulation detection of the power supply circuit can be realized in charging the electric vehicle, and the bridge arm resistor (i.e. Figure 1 and Figure 2 the voltage dividing resistor R1 and R2 in the insulation detection device 100 can be greater than or equal to 500kΩ, so as not to affect the insulation detection of the vehicle end.

[0099] The insulation detection device provided by the embodiment of the present application can be not only used in the above-mentioned charging pile, but also applied to any equipment or product requiring DC side insulation detection.

[0100] Correspondingly, the embodiment of the present application further provides an insulation detection method for a power supply circuit, as shown in the figure, the power supply circuit is provided with a first sampling unit r1 and a second sampling unit r2, and a signal source Us and a reference source Uref are connected in mirror image between a power supply ground PE and the first sampling unit r1 and the second sampling unit r2. Figure 1

[0101] As shown in the figure, it is a flow chart of the insulation detection method provided by the embodiment of the present application. Figure 5

[0102] In step 501, when insulation detection is performed, the signal source injects voltage into the power supply ground of the power supply circuit.

[0103] The voltage can be a square wave signal of a certain frequency.

[0104] In step 502, the first sampling voltage U1 and the corresponding first amplification voltage U2 on the first sampling unit are obtained, and the second sampling voltage U3 and the corresponding second amplification voltage U4 on the second sampling unit are obtained.

[0105] ​​​At step 503, a first voltage is determined according to the first sampling voltage U1 on the first sampling unit and the corresponding first amplification voltage U2, a second voltage is determined according to the second sampling voltage U3 on the second sampling unit and the corresponding second amplification voltage U4, and the insulation of the power supply loop is determined according to the first voltage and the second voltage.

[0106] Specifically, the ground resistance across the power supply loop can be calculated according to the first voltage and the second voltage, and the insulation of the power supply loop can be determined according to the ground resistance across the power supply loop. The specific calculation process and the determination of the insulation can refer to the description in the foregoing embodiment of the insulation detection device, and will not be described here again.

[0107] The insulation detection method provided by the embodiment of the present application can determine the voltage value across the sampling unit by respectively collecting the sampling voltage and the amplification voltage on the first sampling unit and the second sampling unit, determine the voltage signal strength across the sampling unit according to the voltage value, and then determine the high-precision sampling voltage by using appropriate sampling precision, accurately calculate the impedance of the power transmission line to the ground, and determine the insulation of the power supply loop. By using the present application, high-precision signal collection can be realized in the case of imbalance of the impedance of the power transmission line to the ground, thereby improving the precision of the insulation detection.

[0108] Moreover, in the insulation detection method provided by the embodiment of the present application, the insulation detection is performed by injecting voltage into the power supply ground line of the power supply loop by the signal source, and the high-precision voltage of the first sampling unit and the second sampling unit can be obtained at the same time by one-time voltage injection, so that the insulation detection process can be simply and efficiently realized.

[0109] The "connection" appearing in the embodiments of the present application refers to various connection manners such as direct connection or indirect connection, so as to realize the communication between devices, and the embodiments of the present application do not make any limitation on this.

[0110] It should be understood that, in various embodiments of the present application, the size of the serial number of the above processes does not mean the order of execution, and the execution order of the processes should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0111] The above-described embodiments can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented by software, the above-described embodiments can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, the processes or functions described in the embodiments of the present application are wholly or partially generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions can be transferred from one website, computer, server, or data center to another website, computer, server, or data center through a wired or wireless manner.

[0112] In several embodiments provided in the present application, it should be understood that the disclosed methods and devices can be implemented in other ways. For example, the above-described device embodiments are only illustrative; for example, the division of the units is only a logical function division, and actual implementation can have another division manner; for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0113] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, that is, they can be located in one place, or they can be distributed on a plurality of network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiments of the present application.

[0114] The integrated units implemented in the form of software functional units described above can be stored in a computer-readable storage medium. The software functional units stored in a storage medium include a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute part of the steps of the methods described in the embodiments of the present application.

[0115] Although the present application is disclosed as above, the present application is not limited thereto. Any person skilled in the art can make various modifications and changes without departing from the spirit and scope of the present application, and therefore the protection scope of the present application should be subject to the scope defined by the claims.

Claims

1. An insulation testing device, characterized in that, include: The system includes a first sampling unit and a second sampling unit, a first signal processing module, a second signal processing module, a detection module, a signal source, and a reference source, all installed on the power supply circuit. The negative terminal of the signal source and the negative terminal of the reference source are connected to signal ground, the positive terminal of the signal source is connected to the power supply ground line, the first sampling unit is connected between the positive terminal of the reference source and the positive output port of the power supply circuit, and the second sampling unit is connected between the positive terminal of the reference source and the negative output port of the power supply circuit. The signal source is used to inject voltage into the power supply ground wire; The reference source is used to output a fixed voltage; The first signal processing module is used to acquire the first sampling voltage U1 and the corresponding first amplification voltage U2 on the first sampling unit; The second signal processing module is used to acquire the second sampling voltage U3 and the corresponding second amplification voltage U4 on the second sampling unit; The detection module is used to determine a first voltage from a first sampling voltage U1 and a corresponding first amplified voltage U2 based on the relationship between the first amplified voltage U2 and the maximum value of the sampling range, and to determine a second voltage from a second sampling voltage U3 and a corresponding second amplified voltage U4 based on the relationship between the second amplified voltage U4 and the maximum value of the sampling range, and to determine the insulation of the power supply circuit based on the first voltage and the second voltage.

2. The insulation testing device according to claim 1, characterized in that: The first signal processing module includes: The first voltage acquisition unit is used to acquire the first sampling voltage U1 on the first sampling unit and output the first sampling voltage U1 to the detection module. The first voltage amplification unit is used to amplify the first sampling voltage U1 and output the first amplified voltage U2 to the detection module; The second signal processing module includes: The second voltage acquisition unit is used to acquire the second sampling voltage U3 on the second sampling unit and output the second sampling voltage U3 to the detection module; The second voltage amplification unit is used to amplify the second sampling voltage U3 and output the second amplified voltage U4 to the detection module.

3. The insulation testing device according to claim 2, characterized in that, The first voltage acquisition unit and the second voltage acquisition unit are voltage followers.

4. The insulation testing device according to claim 2, characterized in that, The first voltage amplification unit and the second voltage amplification unit are operational amplifiers.

5. The insulation testing device according to claim 2, characterized in that, The detection module is used to calculate the resistance to ground at both ends of the power supply circuit based on the first voltage and the second voltage; and to determine the insulation of the power supply circuit based on the resistance to ground at both ends of the power supply circuit.

6. The insulation testing device according to claim 1, characterized in that, The resistance values ​​of the first sampling unit and the second sampling unit are equal.

7. The insulation testing device according to any one of claims 1 to 6, characterized in that, The output voltage of the reference source is 0~5V.

8. The insulation testing device according to any one of claims 1 to 6, characterized in that, The signal source outputs a square wave signal.

9. A charging pile, characterized in that, Including the insulation testing device as described in any one of claims 1 to 8.

10. An insulation testing method, characterized in that, The method is used in a power supply circuit, which is provided with a first sampling unit and a second sampling unit, as well as a signal source and a reference source mirror-connected between the power supply ground line and the first sampling unit and the second sampling unit; the negative terminals of the signal source and the reference source are connected to signal ground, the positive terminal of the signal source is connected to the power supply ground line, the first sampling unit is connected between the positive terminal of the reference source and the positive output port of the power supply circuit, and the second sampling unit is connected between the positive terminal of the reference source and the negative output port of the power supply circuit; The method includes: During insulation testing, voltage is injected into the power supply ground wire of the power supply circuit through a signal source; Obtain the first sampling voltage U1 and the corresponding first amplification voltage U2 on the first sampling unit, and obtain the second sampling voltage U3 and the corresponding second amplification voltage U4 on the second sampling unit; Based on the relationship between the first amplified voltage U2 and the maximum value of the sampling range, a first voltage is determined from the first sampling voltage U1 and the corresponding first amplified voltage U2. Based on the relationship between the second amplified voltage U4 and the maximum value of the sampling range, a second voltage is determined from the second sampling voltage U3 and the corresponding second amplified voltage U4. The insulation of the power supply circuit is determined based on the first voltage and the second voltage.

11. The insulation testing method according to claim 10, characterized in that, Determining the insulation of the power supply circuit based on the first voltage and the second voltage includes: Calculate the resistance to ground at both ends of the power supply circuit based on the first voltage and the second voltage; The insulation of the power supply circuit is determined based on the ground resistance at both ends of the power supply circuit.

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