Insulation detection method and related equipment

Abstract

The invention relates to an insulation detection method and related equipment thereof. The method comprises the following steps: according to the resistance values of a positive voltage sampling resistor R10, two positive detection resistors R13 and R14, a negative voltage sampling resistor R20 and two negative detection resistors R23 and R24, and a first voltage value Ux1, a second voltage value Uy1, a third voltage value Ux2 and a fourth voltage value Uy2, calculating the resistance values of the positive voltage sampling resistor R10, the two positive detection resistors R13 and R14, the negative voltage sampling resistor R20 and the two negative detection resistors R23 and R24; and calculating an insulation resistance value Rx of the DC bus positive electrode DC + to the protective grounding PE and an insulation resistance value Ry of the DC bus negative electrode DC-to the protective grounding PE. According to the invention, the problem of large insulation detection error in the prior art is solved, and the accuracy of insulation detection is improved.

Description

Technical Field

[0001] The invention relates to the technical field of insulation detection, in particular to an insulation detection method and related equipment. Background Art

[0002] The current insulation detection technology sets up an unbalanced bridge circuit between the DC bus positive pole DC+ and the protective grounding PE, and between the DC bus negative pole DC- and the protective grounding PE, and measures the insulation resistance between the DC bus positive pole and the protective grounding PE, and between the DC bus negative pole DC- and the protective grounding PE based on the resistance and voltage of the unbalanced bridge. This measurement method ignores the influence of other detection circuits on the resistance between the DC bus and the protective grounding, resulting in errors between the detection results and the actual results. Summary of the invention

[0003] The insulation detection method and related equipment provided by the embodiments of the present invention at least solve the problem of large insulation detection error in the related art.

[0004] An insulation detection method is applied to an insulation detection circuit, wherein the insulation detection circuit includes a positive electrode insulation detection unit and a negative electrode insulation detection unit; wherein the positive electrode insulation detection unit includes: a positive electrode voltage sampling resistor R10 connected between a DC bus positive electrode DC+ and a protective grounding PE, two positive electrode detection resistors R13 and R14 connected in series between the DC bus positive electrode DC+ and the protective grounding PE, and a positive electrode resistance switching switch Sa connected between a connection node of the two positive electrode detection resistors R13 and R14 and the protective grounding PE; the negative electrode insulation detection unit includes: a negative electrode voltage sampling resistor R20 connected between a DC bus negative electrode DC- and the protective grounding PE, two negative electrode detection resistors R23 and R24 connected in series between the DC bus negative electrode DC- and the protective grounding PE, and a negative electrode resistance switching switch Sb connected between a connection node of the two negative electrode detection resistors R23 and R24 and the protective grounding PE; the insulation detection method includes:

[0005] The first voltage measurement step: close the positive resistor switching switch Sa, open the negative resistor switching switch Sb, and measure the first voltage value U between the positive pole DC+ of the DC bus and the protective ground PE x1 , measure the second voltage value U between the negative pole DC- of the DC bus and the protective ground PE y1 ; Disconnect the positive resistor switching switch Sa, close the negative resistor switching switch Sb, and measure the third voltage value U from the positive pole DC+ of the DC bus to the protective ground PE x2 , measure the fourth voltage value U between the negative pole DC- of the DC bus and the protective ground PE y2 ;

[0006] Insulation resistance calculation steps: According to the resistance values ​​of the positive electrode voltage sampling resistor R10, the two positive electrode detection resistors R13, R14, the negative electrode voltage sampling resistor R20 and the two negative electrode detection resistors R23, R24, and the first voltage value U x1 , the second voltage value U y1 , the third voltage value U x2 and the fourth voltage value U y2 , calculate the insulation resistance R of the DC bus positive pole DC+ to the protective ground PE x The insulation resistance value R of the negative pole DC- of the DC bus to the protective ground PE y .

[0007] In some embodiments, the insulation resistance value R of the DC bus positive electrode DC+ to the protective ground PE is x for: Insulation resistance R of the negative pole of the DC bus DC- to the protective ground PE y for:

[0008] Among them, U x1 Indicates the first voltage value, U y1 Indicates the second voltage value, U x2 Indicates the third voltage value, U y2 Indicates the fourth voltage value; A=R10||R13, B=R20||(R23+R24); R10=R20, R13=R23, R14=R24; R10 represents the resistance value of the positive voltage sampling resistor, R13 and R14 represent the resistance values ​​of the two positive detection resistors; R20 represents the resistance value of the negative voltage sampling resistor, R23 and R24 represent the resistance values ​​of the two negative detection resistors, and the symbol|| represents parallel connection.

[0009] In some embodiments, the insulation detection method is applied to insulation detection of a charging pile, and the insulation detection method includes:

[0010] Performing insulation testing on the charging pile before starting charging, and / or performing real-time insulation testing on the charging pile during charging; and

[0011] After detecting the insulation resistance value R of the DC bus positive pole DC+ to the protective ground PE x , or the insulation resistance value R of the negative pole of the DC bus DC- to the protective ground PE y When the voltage is less than the set threshold, charging stops and an insulation failure alarm is generated.

[0012] In some embodiments, the first voltage measuring step includes:

[0013] Whenever the positive resistor switching switch Sa or the negative resistor switching switch Sb is turned on or off, the voltage value of the DC bus DC+ and DC- to the protective ground PE is measured after a delay of at least 100ms;

[0014] Perform M voltage measurements to obtain M first voltage values ​​U x1 , M second voltage values ​​U y1 , M third voltage values ​​U x2 and M fourth voltage values ​​U y2 ; Remove p maximum values ​​and q minimum values ​​to obtain M-(p+q) first voltage values ​​U x1 , M-(p+q) second voltage values ​​U y1 , M-(p+q) third voltage values ​​U x2 and M-(p+q) fourth voltage values ​​U y2

[0015] And take the average value for the insulation resistance calculation step.

[0016] In some of these embodiments, the method further comprises:

[0017] Perform the first voltage measurement step N times to obtain N first voltage values ​​U x1 The average value of N second voltage values ​​U y1 The average value of N third voltage values ​​U x2 The average value and N fourth voltage values ​​U y2 The average value of

[0018] Perform the insulation resistance calculation steps N times to obtain the insulation resistance value R of the N DC bus positive poles DC+ to the protective ground PE. x The insulation resistance value R of the negative pole DC- of N DC busbars to the protective ground PE y ;

[0019] The insulation resistance values ​​are screened according to the average value and standard deviation of the insulation resistance values, and the average value of the screened insulation resistance values ​​is taken as the measurement result of this insulation resistance value.

[0020] In some embodiments, the insulation detection circuit further includes: a self-test unit, the self-test unit including: a positive self-test resistor R connected between the positive pole DC+ of the DC bus and the protective ground PE STX , negative pole self-test resistor R connected between the negative pole DC- of the DC bus and the protective ground PE STY , and the positive self-test resistor R STX and negative self-detection resistor R STY The method further comprises:

[0021] Second voltage measurement step: close the self-test switch S2; close the positive resistance switching switch Sa, open the negative resistance switching switch Sb, and measure the fifth voltage value U between the positive pole DC+ of the DC bus and the protective ground PE. STx1 , measure the sixth voltage value U between the negative pole DC- of the DC bus and the protective ground PE STy1 ; Disconnect the positive resistor switching switch Sa, close the negative resistor switching switch Sb, and measure the seventh voltage value U of the DC bus positive pole DC+ to the protective ground PE STx2 , measure the eighth voltage value U between the negative pole DC- of the DC bus and the protective ground PE STy2 ;

[0022] Self-test resistance calculation steps: Based on the insulation resistance value R of the DC bus positive pole DC+ to the protective ground PE x , the insulation resistance value R of the negative pole DC- of the DC bus to the protective ground PE y , the resistance values ​​of the positive electrode voltage sampling resistor R10, the two positive electrode detection resistors R13, R14, the negative electrode voltage sampling resistor R20 and the two negative electrode detection resistors R23, R24, and the fifth voltage value U STx1 , the sixth voltage value U STy1 , the seventh voltage value U STx2 and the eighth voltage value U STy2 , calculate the resistance measurement value R of the positive self-test resistor STX and the resistance measurement value of the negative self-test resistor R STY ;

[0023] Self-check judgment steps: When the resistance measurement value R of the positive self-check resistor is detected STX The numerical deviation from the actual resistance value of the positive self-test resistor is greater than the set threshold, and / or the resistance measurement value R of the negative self-test resistor STY When the numerical deviation from the actual resistance value of the negative electrode self-detection resistor is greater than the set threshold, an insulation detection failure alarm is generated.

[0024] In some embodiments, the resistance measurement value R of the positive electrode self-test resistor STX for:

[0025] The resistance measurement value R of the negative self-test resistor STY for:

[0026] Among them, U STx1 Indicates the fifth voltage value, U STy1 Indicates the sixth voltage value, U STx2 Indicates the seventh voltage value, U STy2 Indicates the eighth voltage value; C = R10 | R13 | Rx 、D=R10∥R13+R14∥R x 、E=R20∥R23∥R y 、F=R20∥R23+R24∥R y ; R10 = R20, R13 = R23, R14 = R24; R10 represents the resistance value of the positive voltage sampling resistor, R13 and R14 represent the resistance values ​​of the two positive detection resistors; R20 represents the resistance value of the negative voltage sampling resistor, R23 and R24 represent the resistance values ​​of the two negative detection resistors, R x Indicates the insulation resistance value of the DC bus positive pole DC+ to the protective ground PE, R y It represents the insulation resistance value of the negative pole of the DC bus DC- to the protective grounding PE. The symbol ∥ represents parallel connection.

[0027] In some of these embodiments, the method further comprises:

[0028] Perform the second voltage measurement step N times to obtain N fifth voltage values ​​U STx1 , N sixth voltage values ​​U STy1 , N seventh voltage values ​​U STx2 and N eighth voltage values ​​U STy2 ;

[0029] Perform the insulation resistance calculation steps N times to obtain the resistance measurement values ​​R of N positive self-test resistors. STX and the resistance measurement value R of N negative self-test resistors STY ;

[0030] The resistance measurement values ​​are screened according to the average value and standard deviation of the resistance measurement values, and the average value of the screened resistance measurement values ​​is taken as the measurement result of this resistance measurement value.

[0031] An electronic device includes: a processor and a memory storing a program, wherein the program includes instructions, and when the instructions are executed by the processor, the processor executes the above method.

[0032] A non-transitory machine-readable medium storing computer instructions, wherein the computer instructions are used to cause a computer to execute the above method.

[0033] The insulation detection method and related equipment provided by the embodiment of the present invention are based on the resistance values ​​of the positive voltage sampling resistor R10, the two positive detection resistors R13 and R14, the negative voltage sampling resistor R20 and the two negative detection resistors R23 and R24, and the first voltage value U x1 , the second voltage value U y1 , the third voltage value U x2 and the fourth voltage value U y2, calculate the insulation resistance R of the DC bus positive pole DC+ to the protective ground PE x The insulation resistance value R of the negative pole DC- of the DC bus to the protective ground PE y , which solves the problem of large insulation detection error in related technologies and improves the accuracy of insulation detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other embodiments can be obtained based on these drawings without creative work.

[0035] Figure 1 4 is a circuit topology diagram of the insulation detection circuit of this embodiment.

[0036] Figure 2 Is an equivalent circuit diagram of the DC line for protective grounding of the embodiment of the present application.

[0037] Figure 3 Is a preferred flow chart of the insulation detection method of this embodiment.

[0038] Figure 4 This is a preferred flow chart of the self-test method in the insulation detection method of this embodiment.

[0039] Figure 5 It is a structural schematic diagram of the electronic device created by the present invention. DETAILED DESCRIPTION

[0040] The embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as being limited to the embodiments described herein, which are instead provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0041] Figure 1 : is a circuit topology diagram of the insulation detection circuit of this embodiment, such as Figure 1As shown, the insulation detection circuit includes: an insulation detection switch S1 for connecting the insulation detection circuit to the circuit loop, a positive insulation detection unit and a negative insulation detection unit; wherein the positive insulation detection unit includes: a positive voltage sampling resistor R10 (composed of a resistor R11 and a resistor R12) connected between the positive pole DC+ of the DC bus and the protective grounding PE, two positive detection resistors R13 and R14 connected in series between the positive pole DC+ of the DC bus and the protective grounding PE, and a positive detection resistor R13 and R14 connected to the two positive detection resistors R13 and R14. A positive pole resistor switching switch Sa between the connection node of R14 and the protective grounding PE; the negative pole insulation detection unit includes: a negative pole voltage sampling resistor R20 (composed of a resistor R11 and a resistor R12) connected between the negative pole DC- of the DC bus and the protective grounding PE, two negative pole detection resistors R23 and R24 connected in series between the negative pole DC- of the DC bus and the protective grounding PE, and a negative pole resistor switching switch Sb connected between the connection node of the two negative pole detection resistors R23 and R24 and the protective grounding PE.

[0042] The insulation detection circuit also includes: a self-test unit, which includes: a positive self-test resistor R connected between the positive pole DC+ of the DC bus and the protective ground PE STX , negative pole self-test resistor R connected between the negative pole DC- of the DC bus and the protective ground PE STY , and the positive self-test resistor R STX and negative self-detection resistor R STY Self-test switch S2 between the connection node and the protective ground PE.

[0043] The insulation detection circuit also includes a microcontroller MCU for controlling, detecting and calculating to execute the insulation detection method.

[0044] The insulation detection method of this embodiment includes the following steps:

[0045] Step 1, first voltage measurement step: close the insulation detection switch S1 and the positive resistor switching switch Sa, open the negative resistor switching switch Sb, and measure the first voltage value U between the DC bus positive pole DC+ and the protective ground PE x1 , measure the second voltage value U between the negative pole DC- of the DC bus and the protective ground PE y1 ; Disconnect the positive resistor switching switch Sa, close the negative resistor switching switch Sb, and measure the third voltage value U from the positive pole DC+ of the DC bus to the protective ground PE x2 , measure the fourth voltage value U between the negative pole DC- of the DC bus and the protective ground PE y2 .

[0046] Step 2, insulation resistance calculation step: according to the resistance values ​​of the positive voltage sampling resistor R10, the two positive detection resistors R13, R14, the negative voltage sampling resistor R20 and the two negative detection resistors R23, R24, and the first voltage value U x1 , the second voltage value U y1 , the third voltage value U x2 and the fourth voltage value U y2 , calculate the insulation resistance R of the DC bus positive pole DC+ to the protective ground PE x The insulation resistance value R of the negative pole DC- of the DC bus to the protective ground PE y .

[0047] Figure 2 is an equivalent circuit diagram of the DC line to protective grounding in an embodiment of the present application, Figure 2 R x Represents the insulation resistance of DC+ to PE, R y Represents the insulation resistance from DC to PE.

[0048] The resistance values ​​of resistor R13 and resistor R23 are equal, and the resistance values ​​of resistor R14 and resistor R24 ​​are equal; when Sa is closed and the insulation resistance is infinite, the resistance value of DC+ to PE is A=R10||R13, and when Sa is disconnected and the insulation resistance is infinite, the resistance value of DC+ to PE is B=R20||(R23+R24).

[0049] In the DC pile product, the insulation detection circuit is a separate module that interacts with the TCU control board through RS485. And the low-voltage working power supply of the insulation detection circuit is controlled by the TCU control board. The two insulation resistance detection input voltages DC+ and DC- are connected to the input and output high voltage of the charging pile respectively. After the charging pile is powered on, the TCU control board controls the insulation detection circuit to power on and notifies the insulation detection circuit to start detecting the insulation resistance of the input and output high-voltage lines to PE.

[0050] refer to Figure 2 , close switch S1, connect the insulation detection circuit to the loop and start insulation detection.

[0051] When Sa is closed and Sb is open, the voltage value U between DC+ and DC- to PE can be measured. x1 , U y1 :

[0052]

[0053] When Sa is disconnected and Sb is closed, the voltage value U between DC+ and DC- to PE can be measured. x2 , U y2 :

[0054]

[0055] Expand the above two equations:

[0056]

[0057] Arranging the above two equations, we can get:

[0058]

[0059] Further expansion:

[0060]

[0061] Subtracting the two equations, we get:

[0062]

[0063] Can be obtained:

[0064]

[0065] Transform the above two equations:

[0066]

[0067] Subtracting the two equations, we get:

[0068]

[0069] Can be obtained:

[0070]

[0071] The difference from the related art is that in the above-mentioned insulation detection method, not only the influence of the unbalanced bridge on the voltage between the DC bus and PE is considered, but also the influence of the voltage sampling resistor used to detect the voltage between the DC bus and PE on the voltage between the DC bus and PE is considered, thereby improving the accuracy of insulation detection.

[0072] In some embodiments, the insulation detection method is applied to the insulation detection of the charging pile, and the insulation detection method includes: performing insulation detection on the charging pile before starting charging, and / or the insulation detection method performs real-time insulation detection on the charging pile during charging; and detecting the insulation resistance value R of the positive pole DC+ of the DC bus to the protective ground PE. x , or the insulation resistance value R of the negative pole of the DC bus DC- to the protective ground PE y When the voltage is less than the set threshold, charging stops and an insulation failure alarm is generated.

[0073] For example, in one embodiment, two threshold values ​​are set, namely 100Ω / V and 500Ω / V; the set threshold value indicates that for every 1V increase in the resistance of the DC bus, its insulation resistance should increase by 100Ω. For example, in a system with a DC bus voltage of 400V, the set threshold values ​​are 40kΩ and 200kΩ respectively; when the insulation resistance value is lower than 40kΩ, charging is immediately stopped and an insulation failure alarm is generated, and the alarm result is a fault; when the insulation resistance value is higher than 40kΩ but lower than 200kΩ, charging is stopped after the current charging task is completed and an insulation failure alarm is generated, and the alarm result is abnormal; when the insulation resistance value is higher than 200kΩ, it indicates that the insulation is normal and no alarm is generated.

[0074] In some embodiments, the first voltage measurement step includes: after controlling the on / off of the positive resistor switching switch Sa or the negative resistor switching switch Sb, delaying at least 100ms to measure the voltage value of the DC bus DC+, DC- to the protective ground PE; performing M voltage measurements to obtain M first voltage values ​​U x1 , M second voltage values ​​U y1 , M third voltage values ​​U x2 and M fourth voltage values ​​U y2 ; Remove p maximum values ​​and q minimum values ​​to obtain M-(p+q) first voltage values ​​U x1 , M-(p+q) second voltage values ​​U y1 , M-(p+q) third voltage values ​​U x2 and M-(p+q) fourth voltage values ​​U y2 And take the average value for the insulation resistance calculation step.

[0075] In some embodiments, the method further includes: performing N first voltage measurement steps to obtain N first voltage values ​​U x1 The average value of N second voltage values ​​U y1 The average value of N third voltage values ​​U x2 The average value and N fourth voltage values ​​U y2 The average value of the insulation resistance is obtained by performing N insulation resistance calculation steps to obtain the insulation resistance value R of the positive pole DC+ of the N DC busbars to the protective ground PE. x The insulation resistance value R of the negative pole DC- of N DC busbars to the protective ground PE y ; The insulation resistance values ​​are screened according to the average value and standard deviation of the insulation resistance values, and the average value of the screened insulation resistance values ​​is taken as the measurement result of this insulation resistance value.

[0076] Figure 3 is a preferred flow chart of the insulation detection method of this embodiment. Figure 3In the example, M is 25, N is 6, and p=q=5. The insulation resistance test takes 10s as a cycle, and is measured 6 times, with each test time less than 1.5s. The MCU controls the switch and closure of the optocouplers Sa and Sb to obtain the voltage values ​​of DC+ and DC- to PE after two switching. Among them, each time the state of Sa and Sb is determined, it is necessary to delay 100ms before starting to collect the voltage value, because through actual measurement, after each change of the state of Sa and Sb, the voltage of DC+ and DC- to PE reaches stability within about 100ms. In each collection cycle, the voltage of DC+ and DC- to PE is collected about 25 times, and the maximum and minimum 5 numbers are removed, and then the average is taken to ensure that the voltage value collected each time is very close to the actual value when the voltage reaches stability after switching. Substitute the final voltage value calculated after each collection cycle into the formula to calculate the insulation resistance value. Each 10s detection cycle will obtain 6 sets of insulation resistance values ​​of DC+ and DC- to PE. Calculate the arithmetic mean u and standard deviation σ of the 6 measured values, then check whether the 6 measured values ​​are within the range of [u-3σ,u+3σ], remove the data out of the range, and recalculate the arithmetic mean u of the remaining data as the final insulation resistance value. The MCU determines whether the insulation resistance value is abnormal based on the measurement results.

[0077] The reliability of the detected insulation resistance is guaranteed by the above-mentioned measurement method.

[0078] In some embodiments, the insulation detection method further includes a self-test method for detecting whether the insulation detection circuit fails. The self-test method includes the following steps:

[0079] Step 1, second voltage measurement step: close the insulation detection switch S1 and the self-test switch S2; close the positive pole resistor switching switch Sa, open the negative pole resistor switching switch Sb, and measure the fifth voltage value U of the DC bus positive pole DC+ to the protective ground PE STx1 , measure the sixth voltage value U between the negative pole DC- of the DC bus and the protective ground PE STy1 ; Disconnect the positive resistor switching switch Sa, close the negative resistor switching switch Sb, and measure the seventh voltage value U of the DC bus positive pole DC+ to the protective ground PE STx2 , measure the eighth voltage value U between the negative pole DC- of the DC bus and the protective ground PE STy2 .

[0080] Step 2, self-test resistance calculation steps: According to the insulation resistance value R of the DC bus positive pole DC+ to the protective ground PE x , the insulation resistance value R of the negative pole DC- of the DC bus to the protective ground PE y, the resistance values ​​of the positive electrode voltage sampling resistor R10, the two positive electrode detection resistors R13, R14, the negative electrode voltage sampling resistor R20 and the two negative electrode detection resistors R23, R24, and the fifth voltage value U STx1 , the sixth voltage value U STy1 , the seventh voltage value U STx2 and the eighth voltage value U STy2 , calculate the resistance measurement value R of the positive self-test resistor STX and the resistance measurement value of the negative self-test resistor R STY .

[0081] Step 3, self-test judgment step: When the resistance measurement value R of the positive self-test resistor is detected STX The numerical deviation from the actual resistance value of the positive self-test resistor is greater than the set threshold, and / or the resistance measurement value R of the negative self-test resistor STY When the numerical deviation from the actual resistance value of the negative electrode self-detection resistor is greater than the set threshold, an insulation detection failure alarm is generated.

[0082] The following describes the resistance measurement value R of the positive self-test resistor. STX and the resistance measurement value of the negative self-test resistor R STY The derivation process.

[0083] The insulation resistances are known to be R x and R y When Sa is closed, the resistance value of DC+ to PE is C = (R11 + R12)

[0084] ∥R13∥R x , DC-to-PE resistance value E=(R21+R22)∥R23∥R y ; When Sa is disconnected, the resistance value of DC+ to PE is D = (R11 + R12) ∥ (R13 + R14) ∥ R x , DC-to-PE resistance F = (R21+R22)∥(R23+R24)

[0085] ∥R y .

[0086] When Sa is closed and Sb is open, the voltage value U between DC+ and DC- to PE can be measured. STx1 , U STy1 :

[0087]

[0088] When Sa is disconnected and Sb is closed, the voltage value U between DC+ and DC- to PE can be measured. STx2 , U STy2 :

[0089]

[0090] Expand the above two equations:

[0091]

[0092] Arranging the above two equations, we can get:

[0093]

[0094] Further expansion:

[0095]

[0096] Multiply the two equations by the coefficient to eliminate R STY , the transformation can be obtained:

[0097]

[0098] Subtracting the two equations, we get:

[0099]

[0100] Can be obtained:

[0101]

[0102] Transform the above two equations to eliminate R STX We can get:

[0103]

[0104] Subtracting the two equations, we get:

[0105]

[0106] Can be obtained:

[0107]

[0108] Among them, U STx1 Indicates the fifth voltage value, U STy1 Indicates the sixth voltage value, U STx2 Indicates the seventh voltage value, U STy2 Indicates the eighth voltage value; C = R10 | R13 | R x 、D=R10∥R13+R14∥R x 、E=R20∥R23∥R y 、F=R20∥R23+R24∥R y; R10 = R20, R13 = R23, R14 = R24; R10 represents the resistance value of the positive voltage sampling resistor, R13 and R14 represent the resistance values ​​of the two positive detection resistors; R20 represents the resistance value of the negative voltage sampling resistor, R23 and R24 represent the resistance values ​​of the two negative detection resistors, R x Indicates the insulation resistance value of the DC bus positive pole DC+ to the protective ground PE, R y It represents the insulation resistance value of the negative pole of the DC bus DC- to the protective grounding PE. The symbol ∥ represents parallel connection.

[0109] In some embodiments, the method further includes: performing the second voltage measurement step N times to obtain N fifth voltage values ​​U STx1 , N sixth voltage values ​​U STy1 , N seventh voltage values ​​U STx2 and N eighth voltage values ​​U STy2 ; Execute the insulation resistance calculation steps N times to obtain the resistance measurement values ​​R of N positive self-test resistors STX and the resistance measurement value R of N negative self-test resistors STY The resistance measurement values ​​are screened according to the average value and standard deviation of the resistance measurement values, and the average value of the screened resistance measurement values ​​is taken as the measurement result of this resistance measurement value.

[0110] Figure 4 is a preferred flow chart of the self-test method in the insulation detection method of this embodiment. Figure 4 Taking N=3 as an example, the MCU records the latest insulation resistance measurement value R x and R y MCU controls switch S2 to close, and the self-test unit is connected to the circuit loop and starts working. During the self-test process, 10 seconds is used as a cycle, and three measurements are made. Each time, the voltage values ​​of DC+ and DC- to PE after two switching are obtained by controlling the output terminals Sa and Sb of the optocoupler, and the corresponding self-test resistance measurement value is calculated. The arithmetic mean u and standard deviation σ of the three measurement values ​​are calculated, and then it is checked whether the three measurement values ​​are within the range of [u-3σ,u+3σ]. If there is one number out of the range, it is eliminated, and the arithmetic mean u of the remaining two numbers is recalculated as the final self-test resistance measurement value R STX and R STY If the resistor R is detected STX and R STY The resistance value is in the range of [450 kΩ, 550 kΩ], that is, the measurement error is within 10% (this error range is an example value and can be other values), indicating that the insulation detection circuit is normal.

[0111] The above embodiments provided in the present application improve the accuracy and reliability of insulation detection. In addition, in some embodiments, the above insulation detection method can not only meet the requirements of the national standard GB / T 18487.1-2023 that "the insulation resistance value is detected once before charging, and the resistance value is lower than 100Ω / V, indicating an abnormality, and an alarm is required within 10s", but also meet the requirements of the European standard IEC 61851-23-2020 that "real-time detection of insulation resistance during charging, an alarm is required if the insulation resistance value is lower than 500Ω / V, and charging must be stopped immediately if it is lower than 100Ω / V, and all operations are completed within 10s", meet the requirements of the American standard UL 2231-2-2020 that "a module self-check is completed every 1 hour during the charging process to confirm that the module itself is normal", and meet the requirements of the American standard and Japanese standard CHAdemo that "real-time detection of insulation resistance value during charging, a resistance value lower than 100Ω / V indicates an abnormality, and an alarm must be issued within 10s", which improves safety while also enhancing the competitiveness of high-voltage DC charging pile products.

[0112] The embodiments of the present invention also provide a non-transitory machine-readable medium storing a computer program, wherein the computer program, when executed by a processor of a computer, is used to cause the computer to execute the method of the embodiments of the present invention.

[0113] The embodiment of the invention also provides an electronic device, comprising: at least one processor; and a memory connected to the at least one processor in communication. The memory stores a computer program that can be executed by the at least one processor, and the computer program is used to enable the electronic device to perform the method of the embodiment of the invention when executed by the at least one processor.

[0114] refer to Figure 5 , a block diagram of an electronic device that can be used as a server or client of an embodiment of the invention will now be described, which is an example of hardware devices that can be applied to various aspects of the invention. The electronic device is intended to represent various forms of digital electronic computer devices, such as laptop computers, desktop computers, workbenches, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the invention described and / or required herein.

[0115] like Figure 5As shown, the electronic device includes a computing unit 501, which can perform various appropriate actions and processes according to a computer program stored in a read-only memory (ROM) 502 or a computer program loaded from a storage unit 508 into a random access memory (RAM) 503. In the RAM 503, various programs and data required for the operation of the electronic device can also be stored. The computing unit 501, the ROM 502, and the RAM 503 are connected to each other via a bus 504. An input / output (I / O) interface 505 is also connected to the bus 504.

[0116] Multiple components in the electronic device are connected to the I / O interface 505, including: an input unit 506, an output unit 507, a storage unit 508, and a communication unit 509. The input unit 506 can be any type of device that can input information to the electronic device, and the input unit 506 can receive input digital or character information, and generate key signal input related to user settings and / or function control of the electronic device. The output unit 507 can be any type of device that can present information, and can include but is not limited to a display, a speaker, a video / audio output terminal, a vibrator, and / or a printer. The storage unit 508 can include but is not limited to a disk, an optical disk. The communication unit 509 allows the electronic device to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks, and can include but is not limited to a modem, a network card, an infrared communication device, and / or a wireless communication transceiver, such as a Bluetooth device, a WiFi device, a WiMax device, a cellular communication device, and / or the like.

[0117] The computing unit 501 may be a variety of general and / or special processing components with processing and computing capabilities. Some examples of the computing unit 501 include, but are not limited to, a CPU, a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing units, various computing units running machine learning model algorithms, digital signal processors (DSPs), and any appropriate processors, controllers, microcontrollers, etc. The computing unit 501 performs the various methods and processes described above. For example, in some embodiments, the method embodiments created by the present invention may be implemented as a computer program, which is tangibly contained in a machine-readable medium, such as a storage unit 508. In some embodiments, part or all of the computer program may be loaded and / or installed on an electronic device via a ROM 502 and / or a communication unit 509. In some embodiments, the computing unit 501 may be configured to perform the above-described method in any other appropriate manner (e.g., by means of firmware).

[0118] The computer program for implementing the method of the present invention can be written in any combination of one or more programming languages. These computer programs can be provided to a processor or controller of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that the computer program, when executed by the processor or controller, enables the functions / operations specified in the flow chart and / or block diagram to be implemented. The computer program can be executed entirely on the machine, partially on the machine, partially on the machine as a stand-alone software package and partially on a remote machine, or entirely on a remote machine or server.

[0119] In the context of the present invention, the machine-readable medium can be a tangible medium that can contain or store a program for use by an instruction execution system, device or equipment or used in combination with an instruction execution system, device or equipment. The machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. The machine-readable signal medium can include, but is not limited to, electronic, magnetic, optical, electromagnetic or infrared systems, devices or equipment, or any suitable combination of the above. A more specific example of a machine-readable storage medium can include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0120] It should be noted that the term "including" and its variations used in the embodiments of the present invention are open inclusions, that is, "including but not limited to". The term "based on" means "based at least in part on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments". The modifications of "one" and "multiple" mentioned in the embodiments of the present invention are illustrative and not restrictive. Those skilled in the art should understand that unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0121] The user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in the embodiments created by the present invention are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with the relevant laws, regulations and standards of relevant countries and regions, and provide corresponding operation entrances for users to choose to authorize or refuse.

[0122] The various steps described in the method implementation methods provided by the embodiments of the present invention can be performed in different orders and / or in parallel. In addition, the method implementation methods may include additional steps and / or omit the steps shown. The scope of protection of the present invention is not limited in this respect.

[0123] The term "embodiment" in this specification refers to specific features, structures or characteristics described in conjunction with the embodiment that can be included in at least one embodiment of the invention. The appearance of this phrase in various places in the specification does not necessarily mean the same embodiment, nor does it mean that it is mutually exclusive with other embodiments and is independent or optional. The various embodiments in this specification are described in a related manner, and the same and similar parts between the various embodiments refer to each other. In particular, for the device, equipment, and system embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts refer to the partial description of the method embodiment.

[0124] The above-described embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of protection. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the attached claims.

Claims

1. An insulation detection method, applied to an insulation detection circuit, wherein the insulation detection circuit comprises an insulation detection switch (S1) for connecting the insulation detection circuit to a circuit loop, a positive insulation detection unit and a negative insulation detection unit; in, The positive electrode insulation detection unit comprises: a positive electrode voltage sampling resistor (R10) connected between a positive electrode (DC+) of a DC bus and a protective ground (PE), two positive electrode detection resistors (R13, R14) connected in series between the positive electrode (DC+) of the DC bus and the protective ground (PE), and a positive electrode resistance switching switch (Sa) connected between a connection node of the two positive electrode detection resistors (R13, R14) and the protective ground (PE); the negative electrode insulation detection unit comprises: a negative electrode voltage sampling resistor (R20) connected between a negative electrode (DC-) of a DC bus and the protective ground (PE), two negative electrode detection resistors (R23, R24) connected in series between the negative electrode (DC-) of the DC bus and the protective ground (PE), and a negative electrode resistance switching switch (Sb) connected between a connection node of the two negative electrode detection resistors (R23, R24) and the protective ground (PE); the insulation detection method comprises: The first voltage measurement step is: closing the insulation detection switch (S1) and the positive resistance switching switch (Sa), opening the negative resistance switching switch (Sb), and measuring the first voltage value (U) of the DC bus positive pole (DC+) to the protective ground (PE); x1 ), measuring the second voltage value (U y1 ); disconnect the positive resistor switching switch (Sa), close the negative resistor switching switch (Sb), and measure the third voltage value (U) of the DC bus positive pole (DC+) to the protective ground (PE) x2 ), measuring a fourth voltage value (U y2 ); Insulation resistance calculation step: according to the resistance values ​​of the positive electrode voltage sampling resistor (R10), the two positive electrode detection resistors (R13, R14), the negative electrode voltage sampling resistor (R20) and the two negative electrode detection resistors (R23, R24), and the first voltage value (U x1 ), the second voltage value (U y1 ), the third voltage value (U x2 ) and the fourth voltage value (U y2 ), calculate the insulation resistance (R x ) and the insulation resistance value (R y ).

2. The method according to claim 1, It is characterized in that The insulation resistance value (R x )for: The insulation resistance value (R y )for: Among them, U x1 Indicates the first voltage value, U y1 Indicates the second voltage value, U x2 represents the third voltage value, U y2 Represents the fourth voltage value; A=R10 / / R13, B=R20 / / (R23+R24); R10=R20, R13=R23, R14=R24; R10 represents the resistance value of the positive voltage sampling resistor, R13 and R14 represent the resistance values ​​of the two positive detection resistors; R20 represents the resistance value of the negative voltage sampling resistor, R23 and R24 represent the resistance values ​​of the two negative detection resistors, and the symbol ∥ represents parallel connection.

3. The method according to claim 1, It is characterized in that The insulation detection method is applied to insulation detection of a charging pile, and the insulation detection method includes: Performing insulation detection on the charging pile before starting charging, and / or the insulation detection method performing real-time insulation detection on the charging pile during charging; and After detecting the insulation resistance value (R x ), or the insulation resistance value (R y ) is less than the set threshold, charging is stopped and an insulation failure alarm is generated.

4. The method according to claim 1, It is characterized in that The first voltage measurement step comprises: Whenever the positive resistor switching switch (Sa) or the negative resistor switching switch (Sb) is controlled to be turned on or off, a voltage value of the DC bus (DC+, DC-) to the protective ground (PE) is measured after a delay of at least 100ms; Perform M voltage measurements to obtain M first voltage values ​​(U x1 ), M second voltage values ​​(U y1 ), M third voltage values ​​(U x2 ) and M fourth voltage values ​​(U y2 ); remove p maximum values ​​and q minimum values ​​to obtain M-(p+q) first voltage values ​​(U x1 ), M-(p+q) second voltage values ​​(U y1 ), M-(p+q) third voltage values ​​(U x2 ) and M-(p+q) fourth voltage values ​​(U y2 ) and take the average value for the insulation resistance calculation step.

5. The method according to claim 4, It is characterized in that The method further comprises: Perform the first voltage measurement step N times to obtain N first voltage values ​​(U x1 ), the average value of N second voltage values ​​(U y1 ) average value, N third voltage values ​​(U x2 ) and the average value of N fourth voltage values ​​(U y2 )’s average value; Execute the insulation resistance calculation step N times to obtain the insulation resistance values ​​(R x ) and the insulation resistance value (R y ); The insulation resistance values ​​are screened according to the average value and standard deviation of the insulation resistance values, and the average value of the screened insulation resistance values ​​is taken as the measurement result of this insulation resistance value.

6. The method according to claim 1, It is characterized in that The insulation detection circuit further includes: a self-test unit, wherein the self-test unit includes: a positive electrode self-test resistor (R STX ), the negative pole self-detection resistor (R) connected between the negative pole of the DC bus (DC-) and the protective ground (PE) STY ), and connected to the positive self-test resistor (R STX ) and the negative self-detection resistor (R STY ) and the protective ground (PE); the method further comprises: The second voltage measurement step is: closing the insulation detection switch (S1) and the self-test switch (S2); closing the positive resistance switching switch (Sa), opening the negative resistance switching switch (Sb), and measuring the fifth voltage value (U) of the DC bus positive pole (DC+) to the protective ground (PE). STx1 ), measuring the sixth voltage value (U STy1 ); disconnect the positive resistor switching switch (Sa), close the negative resistor switching switch (Sb), and measure the seventh voltage value (U) of the DC bus positive pole (DC+) to the protective ground (PE) STx2 ), measuring the eighth voltage value (U STy2 ); Self-test resistance calculation steps: According to the insulation resistance value (R x ), the insulation resistance value (R) of the negative pole of the DC bus (DC-) to the protective ground (PE) y ), the resistance values ​​of the positive electrode voltage sampling resistor (R10), the two positive electrode detection resistors (R13, R14), the negative electrode voltage sampling resistor (R20) and the two negative electrode detection resistors (R23, R24), and the fifth voltage value (U STx1 ), the sixth voltage value (U STy1 ), the seventh voltage value (U STx2 ) and the eighth voltage value (U STy2 ), calculate the resistance measurement value of the positive electrode self-test resistor (R STX ) and the measured resistance value of the negative self-test resistor (R STY ); Self-checking judgment step: When the resistance measurement value (R STX ) is greater than a set threshold value, and / or the measured resistance value (R STY ) and the actual resistance value of the negative electrode self-detection resistor is greater than a set threshold, an insulation detection failure alarm is generated.

7. The method according to claim 6, It is characterized in that The resistance measurement value of the positive self-test resistor (R STX )for: The resistance measurement value of the negative electrode self-test resistor (R STY )for: Among them, U STx1 represents the fifth voltage value, U STy1 represents the sixth voltage value, U STx2 represents the seventh voltage value, U STy2 represents the eighth voltage value; C=R10||R13||R x , D=R10∥(R13+R14)∥R x 、E=R20∥R23∥R y 、F=R20∥(R23+R24)∥R y ; R10 = R20, R13 = R23, R14 = R24; R10 represents the resistance value of the positive voltage sampling resistor, R13 and R14 represent the resistance values ​​of the two positive detection resistors; R20 represents the resistance value of the negative voltage sampling resistor, R23 and R24 represent the resistance values ​​of the two negative detection resistors, R x Indicates the insulation resistance value of the DC bus positive pole (DC+) to the protective ground (PE), R y It represents the insulation resistance value of the negative pole of the DC bus (DC-) to the protective ground (PE), and the symbol ∥ represents parallel connection.

8. The method according to claim 6, It is characterized in that The method further comprises: Perform the second voltage measurement step N times to obtain N fifth voltage values ​​(U STx1 ), N sixth voltage values ​​(U STy1 ), N seventh voltage values ​​(U STx2 ) and N eighth voltage values ​​(U STy2 ); Execute the insulation resistance calculation step N times to obtain the resistance measurement values ​​(R STX ) and the resistance measurement values ​​of the N negative electrode self-test resistors (R STY ); The resistance measurement values ​​are screened according to the average value and standard deviation of the resistance measurement values, and the average value of the screened resistance measurement values ​​is taken as the measurement result of this resistance measurement value.

9. An electronic device, include: A processor and a memory storing a program, wherein the program comprises instructions, which, when executed by the processor, cause the processor to perform the method according to any one of claims 1 to 8.

10. A non-transitory machine-readable medium storing computer instructions, It is characterized in that The computer instructions are used to cause the computer to execute the method according to any one of claims 1 to 8.

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