A safe measurement method for insulation resistance of high-voltage circuits based on coupling unit isolation and independent boost power supply

Abstract

This invention discloses a safe measurement method for the insulation resistance of high-voltage circuits based on coupling unit isolation and independent boost power supply, belonging to the field of high-voltage electrical insulation testing technology. The method includes establishing an isolated injection channel between the measurement end and the high-voltage circuit through a coupling unit; outputting an initial boost test signal from an independent boost power supply unit; generating a test energy index based on the ground response voltage and leakage response current; generating an insulation load withstand threshold based on the test energy index and defining a safe measurement constraint range to determine the boost adjustment result; correcting the test voltage amplitude, boost change slope, and injection duration based on the boost adjustment result to generate an adjustment test signal; calculating the high-voltage circuit insulation resistance value based on the adjustment response voltage and adjustment leakage current, and generating the insulation measurement result. This invention reduces the additional impact of test injection on the tested circuit while maintaining measurement sensitivity, improving the safety, stability, and reliability of insulation resistance measurement.

Description

Technical Field

[0001] This invention belongs to the field of high-voltage electrical insulation testing technology, specifically a method for safe measurement of insulation resistance in high-voltage circuits based on coupling unit isolation and independent voltage boosting power supply. Background Technology

[0002] With the widespread application of new energy vehicles, energy storage equipment, photovoltaic inverters, and high-voltage DC power distribution systems, monitoring the insulation status of high-voltage circuits to ground has become a crucial aspect of electrical safety management. Existing insulation resistance measurement technologies mainly follow the development paths of bridge balance measurement, ground voltage sampling and conversion, low-frequency signal injection measurement, and online detection by insulation monitoring devices. Their core purpose is to obtain the insulation resistance value of the high-voltage circuit to ground and thereby determine insulation degradation or grounding faults. Existing solutions have a certain foundation in static measurement, single-shot evaluation, and general fault detection. However, in scenarios where high-voltage circuits have parasitic parameters, device aging, weak insulation points, and limited injection testing processes, there are still two common shortcomings: one is insufficient control of the additional electrical stress on the circuit under test during the measurement process. The test voltage amplitude, rise process, and duration are mostly fixed settings, making it difficult to balance measurement sensitivity and device safety. The other is the lack of linkage constraints between the measurement results and the injection process. A dynamic adjustment mechanism has not yet been established around the withstand capability of the circuit under test. Therefore, in scenarios with aging filter capacitors, weak isolation devices, and local insulation degradation, problems such as excessive test disturbances, insufficient measurement stability, or decreased reliability of results are likely to occur.

[0003] For example, CN101158701B discloses a high-voltage system voltage and insulation resistance measurement circuit. This scheme calculates the insulation resistance by measuring the voltage to ground at the positive and negative terminals of the high-voltage DC system. The measurement structure is relatively direct, but its focus is on voltage sampling and resistance conversion, without constructing a safety constraint mechanism around the correspondence between injected energy and the withstand capability of the tested circuit. CN102854395B discloses a DC power supply to ground insulation resistance detection circuit and its detection method, which uses a bridge balancing approach to detect the insulation status to ground, but has detection limitations when the positive and negative insulation to ground decreases or approaches simultaneously. CN106080209A proposes an insulation detection scheme combining low-frequency signal injection and a boost circuit, which can complete the insulation judgment between the high-voltage circuit and the vehicle body ground, but the injection process is still mainly based on fixed excitation. CN101365955B discloses a high-voltage insulation monitoring sensor that emphasizes improving monitoring safety through impedance measurement and opto-isolation, but does not further establish a dynamic boost adjustment path based on the testing process. It is evident that existing high-voltage circuit insulation resistance measurement technologies suffer from insufficient injection safety control and inadequate adaptive capability during the measurement process. This invention effectively addresses the issues of significant additional impact on the tested circuit during high-voltage injection and the difficulty in balancing measurement safety and accuracy by employing coupling unit isolation, independent voltage boosting power supply, generation of test energy indicators, determination of insulation load tolerance thresholds, and linkage correction of test voltage amplitude, voltage boosting slope, and injection duration. This invention belongs to the field of high-voltage electrical insulation detection and safety measurement control technology. Summary of the Invention

[0004] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for safe measurement of insulation resistance of high-voltage circuits based on coupling unit isolation and independent boost power supply, comprising: An isolated injection channel is established between the measurement end and the high-voltage circuit through a coupling unit, and an initial boost test signal is output by an independent boost power supply unit; test energy indicators are generated based on the ground response voltage and leakage response current corresponding to the initial boost test signal. An insulation load withstand threshold is generated based on the test energy index, and a safe measurement constraint range is defined based on the insulation load withstand threshold; the boost adjustment result is determined based on the target range corresponding to the test energy index within the safe measurement constraint range. Based on the boost regulation results, the test voltage amplitude, boost change slope, and injection duration of the independent boost power supply unit are corrected, and an regulation test signal is applied to the high-voltage circuit through the coupling unit; after applying the regulation test signal, the regulation response voltage and regulation leakage current of the high-voltage circuit are collected; The high-voltage circuit insulation resistance value is calculated based on the adjustment test signal, the adjustment response voltage, and the adjustment leakage current, and the insulation measurement result is generated based on the high-voltage circuit insulation resistance value.

[0006] As a preferred technical solution for a high-voltage circuit insulation resistance safety measurement method based on coupling unit isolation and independent boost power supply, the initial boost test signal includes: The coupling unit is connected between the measuring terminal and the high-voltage circuit, so that the output terminal of the independent boost power supply unit is connected to the high-voltage circuit through the coupling unit to form an isolated injection channel; The independent boost power supply unit is controlled to apply an initial boost test signal to the high-voltage circuit via the isolation injection channel, and the ground response voltage and leakage response current of the high-voltage circuit are collected during the application of the initial boost test signal.

[0007] As a preferred technical solution for a high-voltage circuit insulation resistance safety measurement method based on coupling unit isolation and independent boost power supply, the generated test energy index includes: Based on the voltage amplitude of the initial boost test signal, the ground response voltage, and the leakage response current, the voltage and current effects of the high-voltage circuit during this injection process are determined, and a test energy index is generated based on the correspondence between the voltage and current effects.

[0008] As a preferred technical solution for a high-voltage circuit insulation resistance safety measurement method based on coupling unit isolation and independent voltage boosting power supply, the defined safety measurement constraint interval includes: The test energy index is graded to obtain the load level corresponding to the current injection intensity of the high-voltage circuit; The insulation load bearing threshold corresponding to the high-voltage circuit is determined based on the load level. The insulation load bearing threshold characterizes the upper limit of the injection intensity that the high-voltage circuit can withstand during insulation measurement. The safety measurement constraint range is defined with zero as the lower limit and the insulation load bearing threshold as the upper limit.

[0009] As a preferred technical solution for a high-voltage circuit insulation resistance safety measurement method based on coupling unit isolation and independent voltage boosting power supply, the voltage boosting regulation results are determined as follows: The safety measurement constraint interval is divided into a first interval, a second interval, and a third interval according to one-third and two-thirds of the insulation load bearing threshold. The first interval is a numerical interval greater than or equal to zero and less than one-third of the insulation load bearing threshold. The second interval is a numerical interval greater than or equal to one-third of the insulation load bearing threshold and less than two-thirds of the insulation load bearing threshold. The third interval is a numerical interval greater than or equal to two-thirds of the insulation load bearing threshold and less than or equal to the insulation load bearing threshold. The test energy index is matched with the first interval, the second interval, and the third interval to determine the target interval to which the test energy index belongs; When the target range of the test energy index is the first range, a boost increase result is generated; when the target range of the test energy index is the second range, a boost maintenance result is generated; when the target range of the test energy index is the third range, a boost decrease result is generated.

[0010] As a preferred technical solution for a high-voltage circuit insulation resistance safety measurement method based on coupling unit isolation and independent boost power supply, the generation and adjustment of the test signal includes: Based on the boost adjustment results, determine the corresponding test voltage amplitude correction, boost change slope correction, and injection duration correction. The output voltage amplitude of the independent boost power supply unit is adjusted according to the test voltage amplitude correction amount, the voltage rise process of the independent boost power supply unit is adjusted according to the boost change slope correction amount, and the signal holding time of the independent boost power supply unit is adjusted according to the injection duration correction amount, thereby obtaining the adjusted test signal.

[0011] As a preferred technical solution for a high-voltage circuit insulation resistance safety measurement method based on coupling unit isolation and independent boost power supply, the determination of the corresponding test voltage amplitude correction, boost change slope correction, and injection duration correction includes: Obtain the boost adjustment result, and determine the adjustment direction of the test voltage amplitude, the adjustment direction of the boost change slope, and the adjustment direction of the injection duration corresponding to the boost adjustment result; When the test voltage amplitude adjustment direction is increasing, a positive test voltage amplitude correction amount is determined; when the test voltage amplitude adjustment direction is maintaining, a zero test voltage amplitude correction amount is determined; when the test voltage amplitude adjustment direction is decreasing, a reverse test voltage amplitude correction amount is determined. When the direction of the boost change slope adjustment is to increase, a positive boost change slope correction amount is determined; when the direction of the boost change slope adjustment is to maintain, a zero boost change slope correction amount is determined; when the direction of the boost change slope adjustment is to decrease, a reverse boost change slope correction amount is determined. When the direction of the injection duration adjustment is to extend, a positive injection duration correction amount is determined; when the direction of the injection duration adjustment is to maintain, a zero injection duration correction amount is determined; when the direction of the injection duration adjustment is to shorten, a reverse injection duration correction amount is determined.

[0012] As a preferred technical solution for a high-voltage circuit insulation resistance safety measurement method based on coupling unit isolation and independent voltage boosting power supply, the calculation of the high-voltage circuit insulation resistance value includes: Extract the stable output segment from the adjustment test signal, and determine the test voltage amplitude corresponding to the stable output segment as the injected test voltage value; simultaneously extract the stable response segments corresponding to the adjustment response voltage and the adjustment leakage current within the stable output segment; The voltage drop to ground is determined based on the adjusted response voltage in the stable response segment, and the insulation voltage drop is determined based on the injected test voltage and the voltage drop to ground; then the insulation resistance value of the high-voltage circuit is calculated based on the insulation voltage drop and the adjusted leakage current in the stable response segment.

[0013] As a preferred technical solution for a high-voltage circuit insulation resistance safety measurement method based on coupling unit isolation and independent boost power supply, the generated insulation measurement results include: The insulation resistance value of the high-voltage circuit is compared with the insulation resistance boundary value to determine the result range to which the insulation resistance value of the high-voltage circuit belongs. When the result range of the high-voltage circuit insulation resistance value is within the qualified range, a normal insulation measurement result is generated; when the result range of the high-voltage circuit insulation resistance value is within the critical range, a critical insulation measurement result is generated; when the result range of the high-voltage circuit insulation resistance value is within the abnormal range, an abnormal insulation measurement result is generated.

[0014] As a preferred technical solution for a high-voltage circuit insulation resistance safety measurement method based on coupling unit isolation and independent voltage boosting power supply, the calculation of the high-voltage circuit insulation resistance value based on the insulation voltage drop value and the regulating leakage current in the stable response segment includes: Within the stable response segment, the regulated leakage current sample values ​​with abrupt amplitude changes are removed, and the stable leakage current value is obtained based on the remaining regulated leakage current sample values. Dividing the insulation voltage drop value by the stable leakage current value yields the insulation resistance value of the high-voltage circuit. The beneficial effects of this invention are as follows: This invention forms a test path separated from the high-voltage circuit by isolating the injection and independent boost power supply steps through a coupling unit, and generates test energy indicators based on the ground response voltage and leakage response current, thereby corresponding the injection intensity with the state of the circuit under test; furthermore, by using the insulation load bearing threshold and the safe measurement constraint range, the boost adjustment result is controlled in segments to reduce the impact of excessive injection on weak insulation points and aging devices; furthermore, by linking the test voltage amplitude, boost change slope, and injection duration, the matching between the adjustment test signal and the circuit state is improved; finally, the insulation resistance value is calculated based on the adjustment response voltage and adjustment leakage current, thereby improving measurement accuracy and measurement safety. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 This is a schematic diagram of the method flow of the present invention. Detailed Implementation

[0016] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0017] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0018] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0019] Secondly, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0020] Example 1 Reference Figure 1This embodiment provides a safe measurement method for the insulation resistance of a high-voltage circuit based on coupling unit isolation and independent boost power supply, including: S1. An isolated injection channel is established between the measurement terminal and the high-voltage circuit through a coupling unit, and an initial boost test signal is output by an independent boost power supply unit; test energy indicators are generated based on the ground response voltage and leakage response current under the action of the initial boost test signal. It should be noted that in this step: S1.1 Connect the coupling unit between the measuring end and the high-voltage circuit, so that the output end of the independent boost power supply unit is connected to the high-voltage circuit through the coupling unit to form an isolated injection channel; S1.2 Control the independent boost power supply unit to apply the initial boost test signal to the high voltage circuit through the isolation injection channel, and collect the ground response voltage and leakage response current of the high voltage circuit during the application of the initial boost test signal.

[0021] S1.3. Based on the voltage amplitude, ground response voltage, and leakage response current of the initial boost test signal, determine the voltage and current effects of the high-voltage circuit during this injection process, and generate test energy indicators based on the correspondence between the voltage and current effects.

[0022] In a preferred embodiment, the coupling unit includes a current-limiting resistor, a disconnecting switch, a unidirectional suppressor, and a high-voltage disconnecting relay connected in series in the injection branch. The independent boost power supply unit includes a DC input module, an isolation conversion module, a boost output module, and an output regulation module. The high-voltage circuit includes a high-voltage positive bus, a high-voltage negative bus, a parasitic capacitance branch to ground, and an insulation resistance branch. The positive injection terminal of the measurement end is connected to the current-limiting resistor via the high-voltage disconnecting relay. The other end of the current-limiting resistor is connected to the high-voltage output terminal of the boost output module. The reference terminal of the boost output module is connected to the equipment ground. The unidirectional suppressor is connected in parallel across the output terminals of the boost output module. The disconnecting switch is located on the control side of the high-voltage disconnecting relay to connect the measurement end to the high-voltage circuit before the measurement begins and disconnect the measurement end from the high-voltage circuit after the measurement ends. Under the aforementioned connection method, the independent boost power supply unit and the measured high-voltage circuit are electrically isolated through the coupling unit. The injected current enters the high-voltage circuit through the current-limiting resistor and then returns to the reference ground through the high-voltage circuit's ground insulation branch and ground parasitic capacitance branch, thereby forming a complete isolated injection channel. This structure separates the test power supply from the vehicle-mounted high-voltage bus or industrial high-voltage bus, and also clearly defines and fixes the injection path, return path, and shutdown path, which facilitates the subsequent acquisition of the ground response voltage and leakage response current.

[0023] In a preferred embodiment, the access process in S1.1 is performed as follows: first, the high-voltage circuit is disconnected from the external load or placed in measurement mode; then, the control board outputs a relay drive signal to close the high-voltage isolation relay, followed by the conduction of the isolating switch, thereby establishing an injection path from the high-voltage output terminal of the independent boost power supply unit, the current-limiting resistor, the high-voltage isolation relay, the measurement terminal, the high-voltage circuit, to the equipment ground; after the injection path is established, the voltage sampling unit is connected between the high-voltage positive bus and the equipment ground, and the current sampling unit is connected in series to the output side of the independent boost power supply unit. The voltage sampling unit preferably uses a high-resistance voltage divider network in conjunction with an isolation sampling chip, and the current sampling unit preferably uses a Hall current sensor or a sampling resistor in conjunction with an isolation amplifier.

[0024] In a preferred embodiment, the initial boost test signal is a DC boost signal that starts from 0V and gradually increases to the target test voltage according to a fixed rise process. The initial boost test signal includes a rising segment and a short-time stabilization segment. The rising segment is used to observe the high-voltage circuit's response to changes in injection intensity, and the stabilization segment is used to obtain a relatively stable ground response voltage and leakage response current at the initial injection moment. Taking the high-voltage circuit of the power battery as an example, the DC input of the independent boost power supply unit is a 24V auxiliary power supply. After passing through the isolation conversion module and the boost output module, it outputs a test voltage adjustable in the range of 0V to 500V. In this embodiment, the target test voltage of the initial boost test signal is selected as 150V, the voltage rise process is selected as rising from 0V to 150V within 20ms, and the short-time stabilization segment is selected as 30ms. The reason for selecting 150V as the initial value is that this value is lower than the normal operating voltage of a common 600V to 800V high-voltage platform, and it can still form a detectable small leakage response current under high insulation conditions, which is convenient for subsequent graded judgment.

[0025] In a preferred embodiment, the acquisition process in S1.2 is performed as follows: before the independent boost power supply unit outputs the initial boost test signal, the control board synchronously starts the voltage sampling unit and the current sampling unit; during the rising segment of the initial boost test signal, the ground response voltage and leakage response current are continuously acquired; after the initial boost test signal enters the short-time stable segment, the ground response voltage and leakage response current are continued to be acquired until the end of the short-time stable segment; subsequently, the ground response voltage and leakage response current are arranged into a set of injection response sequences according to their common time sequence. Preferably, the sampling frequency of the voltage sampling unit is 20kHz, and the sampling frequency of the current sampling unit is 20kHz to avoid the ground response voltage and leakage response current not corresponding due to different sampling intervals. In a specific example, when the initial boost test signal rises to 150V, the measured ground response voltage is concentrated between 128V and 132V in the stable segment, and the leakage response current is concentrated between 0.26mA and 0.32mA in the stable segment.

[0026] In a preferred embodiment, the voltage action in S1.3 refers to the comprehensive voltage applied to the high-voltage circuit by the initial boost test signal during this injection, and the current action refers to the comprehensive leakage current generated by the high-voltage circuit under this comprehensive voltage application. Specifically, the following state of the high-voltage circuit to the applied test voltage is first determined based on the change process of the voltage amplitude and ground response voltage of the initial boost test signal. Then, the absorption degree of the injected voltage by the insulation branch of the high-voltage circuit is determined based on the change range of the leakage response current in the rising segment and the short-time stable segment. After that, the voltage action and the current action are correlated to obtain the test energy index. The test energy index is preferably a single numerical index, the value of which increases with the increase of the voltage amplitude of the initial boost test signal, the increase of the following degree of the ground response voltage, and the increase of the leakage response current. Further, in this embodiment, the test energy index is set as a set of injection intensity values ​​under a unified dimension, which are obtained by the control board by looking up a table based on the correspondence between the voltage amplitude of the initial boost test signal, the ground response voltage, and the leakage response current. In the 150V injection example above, if the ground response voltage is stable at around 130V and the leakage response current is stable at around 0.29mA, the corresponding generated test energy index is 32; if the leakage response current increases to 0.75mA under the same injection conditions, the corresponding generated test energy index can be increased to 71.

[0027] It should be noted that existing high-voltage insulation measurements often suffer from problems such as excessive coupling between the test power supply and the high-voltage system under test, unclear injection paths, difficulty in controlling the initial test intensity, and insufficient early response data to support subsequent safety adjustments. By coordinating the coupling unit, independent boost power supply unit, and initial boost test signal, an injection measurement process with a clear structure, clear loop, and fixed sampling object can be formed at the initial stage of measurement. This provides a consistent data basis for the generation of the insulation load withstand threshold and the determination of the boost adjustment results, thereby reducing initial injection disturbances, improving safety in the initial stage of testing, and enhancing the stability of subsequent adjustment data.

[0028] S2. Generate the insulation load withstand threshold based on the test energy index, and define the safe measurement constraint range based on the insulation load withstand threshold; determine the boost adjustment result based on the target range corresponding to the test energy index within the safe measurement constraint range. Note that the following should be noted in this step: S2.1. The test energy index is graded to obtain the load level corresponding to the current injection intensity of the high-voltage circuit; S2.2 Determine the insulation load bearing threshold corresponding to the high-voltage circuit according to the load level. The insulation load bearing threshold characterizes the upper limit of the injection intensity that the high-voltage circuit can withstand during the insulation measurement process. S2.3. Define the safety measurement constraint range with zero as the lower limit and the insulation load bearing threshold as the upper limit; S2.4. Divide the safety measurement constraint interval into a first interval, a second interval, and a third interval according to one-third and two-thirds of the insulation load bearing threshold. The first interval is a numerical interval greater than or equal to zero and less than one-third of the insulation load bearing threshold. The second interval is a numerical interval greater than or equal to one-third of the insulation load bearing threshold and less than two-thirds of the insulation load bearing threshold. The third interval is a numerical interval greater than or equal to two-thirds of the insulation load bearing threshold and less than or equal to the insulation load bearing threshold. S2.5 Match the test energy index with the first interval, the second interval, and the third interval to determine the target interval to which the test energy index belongs; S2.6 When the target range of the test energy index is the first range, a boost increase result is generated; when the target range of the test energy index is the second range, a boost maintenance result is generated; when the target range of the test energy index is the third range, a boost decrease result is generated.

[0029] In a preferred embodiment, the grading process in S2.1 uses a fixed grading method. Specifically, the test energy index is first mapped to a uniform distribution range of 0 to 100, and then divided into four load levels according to 0 to 25, 26 to 50, 51 to 75, and 76 to 100, respectively denoted as low load level, low-medium load level, medium-high load level, and high load level. The low load level indicates that the current injection intensity of the high-voltage circuit is low, and the insulation branch absorbs less during the injection process; the low-medium load level indicates that the high-voltage circuit has a clear response but is still in a relatively mild state; the medium-high load level indicates that the response of the high-voltage circuit to the current injection intensity is quite obvious; and the high load level indicates that the high-voltage circuit is close to the upper limit of the acceptable injection intensity under the current injection conditions. Using a four-level grading method ensures a stable correspondence between the test energy index and subsequent threshold determination, and also avoids excessively dense distinction boundaries due to too many levels. In the example of S1 above, the test energy index is 32, corresponding to the low-medium load level; if the test energy index is 71, the corresponding load level is the medium-high load level.

[0030] In a preferred embodiment, the insulation load tolerance threshold in S2.2 is determined according to the load level. Specifically, for low load levels, the insulation load tolerance threshold is 90; for medium-low load levels, it is 75; for medium-high load levels, it is 60; and for high load levels, it is 45. The insulation load tolerance threshold is not the rated operating voltage or rated operating current of the tested object, but rather the upper limit of the injection intensity corresponding to the uniform distribution range of the test energy index. Furthermore, the closer the current injection state is to the weak insulation state, the lower the corresponding insulation load tolerance threshold, and the smaller the subsequent allowable adjustment space; the closer the current injection state is to the high insulation state, the higher the corresponding insulation load tolerance threshold, and the larger the subsequent allowable adjustment space. Taking the aforementioned medium-low load level as an example, when the test energy index is 32, the corresponding determined insulation load tolerance threshold is 75; if the test energy index is 71, the corresponding determined insulation load tolerance threshold is 60. By setting the insulation load tolerance threshold as a fixed upper limit determined after classification, the method for defining the subsequent safety measurement constraint range can be clearly and uniquely defined.

[0031] In a preferred embodiment, the safety measurement constraint interval in S2.3 is defined as follows: the value of 0 is determined as the starting boundary of the safety measurement constraint interval, the insulation load tolerance threshold is determined as the ending boundary of the safety measurement constraint interval, and the entire range of values ​​between the value of 0 and the insulation load tolerance threshold is defined as the safety measurement constraint interval. This interval represents the range of injection intensity allowed by subsequent adjustment test signals under the initial response conditions of the current high-voltage circuit. Taking the aforementioned low-to-medium load level example, if the insulation load tolerance threshold is 75, then the safety measurement constraint interval is 0 to 75; taking the aforementioned high-to-medium load level example, if the insulation load tolerance threshold is 60, then the safety measurement constraint interval is 0 to 60.

[0032] In a preferred embodiment, the interval division in S2.4 is performed as follows: using the position at 1 / 3 of the insulation load bearing threshold as the first boundary position and the position at 2 / 3 of the insulation load bearing threshold as the second boundary position, the safety measurement constraint interval is sequentially divided into a first interval, a second interval, and a third interval. Taking the aforementioned insulation load bearing threshold of 75 as an example, the first interval is 0 to 25, the second interval is 25 to 50, and the third interval is 50 to 75; taking the aforementioned insulation load bearing threshold of 60 as an example, the first interval is 0 to 20, the second interval is 20 to 40, and the third interval is 40 to 60.

[0033] In a preferred embodiment, the target interval determination in S2.5 is performed as follows: the test energy index is compared sequentially with the numerical boundaries of the first interval, the second interval, and the third interval. When the test energy index falls within the start and end boundary range of a certain interval, that interval is determined to be the target interval. Taking the aforementioned insulation load bearing threshold of 75 as an example, if the test energy index is 32, then the test energy index is greater than 25 and less than 50, therefore the target interval is determined to be the second interval; if the test energy index is 18, then the target interval is determined to be the first interval; if the test energy index is 62, then the target interval is determined to be the third interval.

[0034] In a preferred embodiment, the boost adjustment result in S2.6 is generated uniquely according to the target interval. Specifically, when the target interval is the first interval, it indicates that the current injection intensity is too low and the high-voltage circuit has not yet entered the appropriate measurement response range, so a boost increase result is generated; when the target interval is the second interval, it indicates that the current injection intensity is within the appropriate measurement range, so a boost maintenance result is generated; when the target interval is the third interval, it indicates that the current injection intensity is close to the upper edge of the injection under the current conditions, so a boost decrease result is generated. Taking the aforementioned example, when the test energy index is 18, a boost increase result is generated; when the test energy index is 32, a boost maintenance result is generated; and when the test energy index is 62, a boost decrease result is generated.

[0035] It should be noted that while the response data obtained from the initial measurement can reflect the trend of the insulation state, without a unified classification and threshold boundary, it is difficult to provide a stable and repeatable basis for safety adjustment. By first generating the load level, then determining the insulation load-bearing threshold, and subsequently defining the safety measurement constraint range and determining the target range, the original injection response can be transformed into a judgment structure with a clear upper limit boundary and a clear adjustment direction. This results in the beneficial effects of unique subsequent adjustment results, clear adjustment basis, and the ability to complete safety measurement control along the same logic under different insulation states.

[0036] S3. Based on the boost regulation results, correct the test voltage amplitude, boost change slope, and injection duration of the independent boost power supply unit, and apply a regulation test signal to the high-voltage circuit through the coupling unit; after applying the regulation test signal, acquire the regulation response voltage and regulation leakage current of the high-voltage circuit. Note that the following should be noted in this step: S3.1. Based on the boost adjustment results, determine the corresponding test voltage amplitude correction, boost change slope correction, and injection duration correction. Specifically, The corresponding correction amounts for test voltage amplitude, boost slope, and injection duration include: S3.1.1 Obtain the boost adjustment result and determine the adjustment direction of the test voltage amplitude, the adjustment direction of the boost change slope, and the adjustment direction of the injection duration corresponding to the boost adjustment result; S3.1.2 When the test voltage amplitude adjustment direction is increasing, determine the positive test voltage amplitude correction amount; when the test voltage amplitude adjustment direction is maintaining, determine the zero test voltage amplitude correction amount; when the test voltage amplitude adjustment direction is decreasing, determine the reverse test voltage amplitude correction amount. S3.1.3 When the direction of the pressure change slope adjustment is to increase, determine the positive pressure change slope correction amount; when the direction of the pressure change slope adjustment is to maintain, determine the zero pressure change slope correction amount; when the direction of the pressure change slope adjustment is to decrease, determine the reverse pressure change slope correction amount. S3.1.4 When the direction of injection duration adjustment is to extend, determine the correction amount for positive injection duration; when the direction of injection duration adjustment is to maintain, determine the correction amount for zero injection duration; when the direction of injection duration adjustment is to shorten, determine the correction amount for reverse injection duration.

[0037] S3.2 Adjust the output voltage amplitude of the independent boost power supply unit according to the test voltage amplitude correction amount, adjust the voltage rise process of the independent boost power supply unit according to the boost change slope correction amount, and adjust the signal holding time of the independent boost power supply unit according to the injection duration correction amount to obtain the adjustment test signal.

[0038] Regarding step S3, in this embodiment, the test voltage amplitude, boost change slope, and injection duration of the independent boost power supply unit are corrected based on the boost regulation results, and an adjustment test signal is applied to the high-voltage circuit through the coupling unit. After applying the adjustment test signal, the adjustment response voltage and adjustment leakage current of the high-voltage circuit are collected, specifically including the following: In a preferred embodiment, the correction amount in S3.1 is determined using a direction correspondence table. Specifically, the boost adjustment result is first obtained, and then the adjustment direction of the test voltage amplitude, the adjustment direction of the boost change slope, and the adjustment direction of the injection duration are determined based on the boost adjustment result. Subsequently, the correction amount of the test voltage amplitude, the correction amount of the boost change slope, and the correction amount of the injection duration are retrieved from the correction amount table corresponding to each adjustment direction. Preferably, when the boost adjustment result is a boost increase result, the adjustment direction of the test voltage amplitude, the adjustment direction of the boost change slope, and the adjustment direction of the injection duration are all taken as increasing directions; when the boost adjustment result is a boost maintenance result, all three are taken as maintenance directions; when the boost adjustment result is a boost decrease result, the adjustment direction of the test voltage amplitude and the adjustment direction of the boost change slope are taken as decreasing directions, and the adjustment direction of the injection duration is taken as shortening directions. To ensure the feasibility of this embodiment, the correction scale can be set as follows: the forward test voltage amplitude correction is 20V, the zero test voltage amplitude correction is 0V, and the reverse test voltage amplitude correction is -20V; the forward boost change slope correction is 3V increased every 1ms, the zero boost change slope correction is 0V increased every 1ms, and the reverse boost change slope correction is 3V decreased every 1ms; the forward injection duration correction is extended by 20ms, the zero injection duration correction is 0ms, and the reverse injection duration correction is shortened by 15ms. Taking the generation of the boost maintenance result in step S2 as an example, the corresponding determined test voltage amplitude correction is 0V, the boost change slope correction is 0V increased every 1ms, and the injection duration correction is 0ms; if the boost increase result is generated, the corresponding determined test voltage amplitude correction is 20V, the boost change slope correction is 3V increased every 1ms, and the injection duration correction is extended by 20ms.

[0039] In a preferred embodiment, the working process of S3.1.1 to S3.1.4 can be specifically described as follows: After receiving the boost regulation result, the control board first determines three types of regulation directions in the direction mapping table, then retrieves the correction values ​​corresponding to the three types of regulation directions from the correction amount mapping table, and combines the three correction values ​​into a set of regulation parameters. The set of regulation parameters includes one voltage amplitude correction value, one rise process correction value, and one duration correction value. Using this method, a single boost regulation result can be expanded into three specific control quantities that can directly affect the output process of the independent boost power supply unit. Taking the aforementioned initial boost test signal of 150V, rising to the target voltage in 20ms, and a short-term stable period of 30ms as an example, if the boost regulation result is a boost increase, the set of regulation parameters corresponds to a target test voltage of 170V, rising to the target voltage in 17ms, and a stable output in 50ms; if the boost regulation result is a boost decrease, the set of regulation parameters corresponds to a target test voltage of 130V, rising to the target voltage in 23ms, and a stable output in 15ms.

[0040] In a preferred embodiment, the generation of the adjustment test signal in S3.2 is performed as follows: a test voltage amplitude correction is superimposed on the target test voltage of the initial boost test signal; a boost change slope correction is applied to the voltage rise process of the initial boost test signal; and an injection duration correction is applied to the stable output duration of the initial boost test signal. Subsequently, the independent boost power supply unit re-outputs the corrected adjustment test signal, which is then applied to the high-voltage circuit via the coupling unit. Here, the adjustment of the voltage rise process specifically manifests as a change in the increase in output voltage per unit time, and the adjustment of the stable output duration specifically manifests as a change in the plateau length that maintains the target test voltage after it is reached. Using this method, the adjustment test signal can change in voltage amplitude, as well as in the rise process and the stable duration, relative to the initial boost test signal, thereby making the secondary measurement closer to the acceptable injection range of the current high-voltage circuit. In a specific example, when the boost regulation result given in step S2 is a boost maintenance result, the regulation test signal still uses a target test voltage of 150V, a rise time of 20ms, and a stable output time of 30ms; when the boost regulation result is a boost increase result, the regulation test signal uses a target test voltage of 170V, a rise time of 17ms, and a stable output time of 50ms; when the boost regulation result is a boost decrease result, the regulation test signal uses a target test voltage of 130V, a rise time of 23ms, and a stable output time of 15ms. Subsequently, the voltage sampling unit and the current sampling unit synchronously acquire the regulation response voltage and regulation leakage current again, and use them as input data for step S4.

[0041] It should be noted that if only the directional results of increasing, maintaining, or decreasing the boost voltage are given, without further decomposition into the three levels of test voltage amplitude, boost change slope, and injection duration, the subsequent test signal still lacks an engineering-practical adjustment basis. By breaking down the boost adjustment result into three correction quantities and forming the adjustment test signal accordingly, subsequent secondary measurements can have a clear adjustment direction, a clear adjustment amplitude, and a clear time process. This brings the beneficial effects of a specific adjustment strategy, repeatable test process, and the ability to complete adaptive injection control under different insulation conditions using the same hardware structure.

[0042] S4. Calculate the insulation resistance of the high-voltage circuit based on the adjusted test signal, adjusted response voltage, and adjusted leakage current. Note the following in this step: The calculation of the insulation resistance value of the high-voltage circuit includes: S4.1 Extract the stable output segment from the regulation test signal, and determine the test voltage amplitude corresponding to the stable output segment as the injected test voltage value; simultaneously extract the stable response segments corresponding to the regulation response voltage and regulation leakage current within the stable output segment; S4.2 Determine the voltage drop to ground based on the regulating response voltage in the stable response section, and determine the insulation voltage drop based on the injected test voltage and the voltage drop to ground; then calculate the insulation resistance value of the high-voltage circuit based on the insulation voltage drop and the regulating leakage current in the stable response section. S4.2.1. Within the stable response segment, eliminate the regulated leakage current sampling values ​​with abrupt amplitude changes, and obtain the stable leakage current value based on the remaining regulated leakage current sampling values. S4.2.2 Divide the insulation voltage drop value by the stable leakage current value to obtain the insulation resistance value of the high-voltage circuit; S4.3 Compare the insulation resistance value of the high-voltage circuit with the insulation resistance boundary value to determine the result range to which the insulation resistance value of the high-voltage circuit belongs; S4.4 When the result range of the high-voltage circuit insulation resistance value is within the qualified range, a normal insulation measurement result is generated; when the result range of the high-voltage circuit insulation resistance value is within the critical range, a critical insulation measurement result is generated; when the result range of the high-voltage circuit insulation resistance value is within the abnormal range, an abnormal insulation measurement result is generated.

[0043] In a preferred embodiment, the stable output segment extraction in S4.1 is performed as follows: First, in the adjustment test signal, a segment whose voltage change amplitude continuously decreases and enters a stable state is searched along the time sequence. When the voltage difference between multiple consecutive sampling points is less than a set small difference value, the segment is determined as a stable output segment. Then, the corresponding test voltage amplitude within the stable output segment is determined as the injected test voltage value. Subsequently, sampling segments corresponding one-to-one with the start and end times of the stable output segment are selected from the adjustment response voltage and adjustment leakage current, and these sampling segments are determined as stable response segments. To facilitate direct implementation by those skilled in the art, in this embodiment, the set small difference value can be selected as the voltage difference between any two adjacent sampling points within 10 consecutive sampling points not exceeding 0.5V. If the adjustment test signal enters a stable platform after 20ms, and the output voltage is concentrated between 149.5V and 150.4V between 20ms and 50ms, then 20ms to 50ms can be defined as the stable output segment, and the average test voltage value of 150V in this segment can be defined as the injection test voltage value. Correspondingly, the sampled values ​​of the adjustment response voltage and the adjustment leakage current between 20ms and 50ms can be defined as the stable response segment.

[0044] In a preferred embodiment, the voltage drop to ground in S4.2 is determined by the regulating response voltage in the stable response segment. Specifically, the central tendency of the regulating response voltage in the stable response segment is first determined, and then the voltage value corresponding to the central tendency is determined as the voltage drop to ground. Preferably, the average value of all regulating response voltage samples in the stable response segment can be used as the voltage drop to ground. Then, the insulation voltage drop is obtained by subtracting the voltage drop to ground from the injected test voltage value; then, the insulation voltage drop is divided by the stable leakage current value to obtain the insulation resistance value of the high-voltage circuit. To avoid bringing transient spikes into the calculation, the amplitude mutation sampling value elimination in S4.2.1 is performed as follows: In the stable response segment, the regulating leakage current difference between adjacent sampling points is compared one by one. When a sampling point shows a significant jump compared with its adjacent sampling points before and after it, the sampling point is marked as an amplitude mutation sampling value and eliminated; then, the stable leakage current value is calculated based on the remaining regulating leakage current sampling values. Preferably, sampling points that exceed the distribution range of most sampling values ​​in the stable response segment by more than 20% can be identified as amplitude mutation sampling values. In a specific application scenario, taking the offline testing of a 600V power battery assembly as an example, the adjusted test signal is determined in step S3 to be a target test voltage of 150V and a stable output range of 30ms. Within the stable output range, the adjusted response voltage sampling values ​​are concentrated between 131.2V and 132.8V, with an average value of 132V, which can be determined as the voltage drop to ground. The adjusted leakage current sampling values ​​are mostly concentrated between 0.34mA and 0.38mA, with two jump points of 0.53mA and 0.56mA respectively. After removing these two jump points, the average value of the remaining sampling values ​​is 0.36mA, which can be determined as the stable leakage current value. Subtracting the voltage drop to ground of 132V from the injected test voltage of 150V yields an insulation voltage drop of 18V. Dividing 18V by 0.36mA yields a high-voltage circuit insulation resistance of 50kΩ.

[0045] In a preferred embodiment, the determination of the result range in S4.3 is performed as follows: An insulation resistance threshold value is pre-set and divided into a qualified threshold value and a critical threshold value. Then, the high-voltage circuit insulation resistance value is compared sequentially with the qualified threshold value and the critical threshold value to determine the result range to which the high-voltage circuit insulation resistance value belongs. Taking the high-voltage circuit insulation safety test scenario of a power battery as an example, 100kΩ can be determined as the qualified threshold value, and 60kΩ as the critical threshold value. When the high-voltage circuit insulation resistance value is greater than or equal to 100kΩ, it is determined to be in the qualified range; when the high-voltage circuit insulation resistance value is less than 100kΩ but greater than or equal to 60kΩ, it is determined to be in the critical range; when the high-voltage circuit insulation resistance value is less than 60kΩ, it is determined to be in the abnormal range. Taking the aforementioned example of a high-voltage circuit insulation resistance value of 50kΩ, since 50kΩ is less than 60kΩ, its result range is determined to be the abnormal range. For example, in another set of prototype measurements, if the average adjustment response voltage is 140V and the stable leakage current is 0.15mA, the insulation voltage drop is 10V, and the corresponding high-voltage circuit insulation resistance is approximately 66.7kΩ. This result range can be determined to be the critical range. If the average adjustment response voltage is 147V and the stable leakage current is 0.02mA, the insulation voltage drop is 3V, and the corresponding high-voltage circuit insulation resistance is 150kΩ. This result range can be determined to be the acceptable range.

[0046] In a preferred embodiment, the insulation measurement results in S4.4 are uniquely generated according to the result range. Specifically, when the result range of the high-voltage circuit insulation resistance value is within the qualified range, a normal insulation measurement result is generated, and the insulation status is indicated as normal in the measurement record; when the result range of the high-voltage circuit insulation resistance value is within the critical range, a critical insulation measurement result is generated, and the insulation status is indicated as critical in the measurement record; when the result range of the high-voltage circuit insulation resistance value is within the abnormal range, an abnormal insulation measurement result is generated, and the insulation status is indicated as abnormal in the measurement record. In the power battery module assembly and testing scenario, a normal insulation measurement result corresponds to the tested high-voltage circuit being able to proceed to the next process; a critical insulation measurement result corresponds to the tested high-voltage circuit needing to proceed to the verification station; and an abnormal insulation measurement result corresponds to the tested high-voltage circuit needing to stop processing and be transferred to the insulation defect investigation station. In a specific example, when the high-voltage circuit insulation resistance value is 150kΩ, a normal insulation measurement result is output; when the high-voltage circuit insulation resistance value is 66.7kΩ, a critical insulation measurement result is output; and when the high-voltage circuit insulation resistance value is 50kΩ, an abnormal insulation measurement result is output.

[0047] The purpose of step S4 is to obtain a high-voltage circuit insulation resistance value with a clear numerical source under the safe injection conditions adjusted in step S3, based on the adjusted test signal, adjusted response voltage, and adjusted leakage current. This results in an insulation measurement that can be directly used for quality assessment or fault screening. The technical problem addressed by this step is that without defining the stable output phase of the adjusted test signal, eliminating abrupt changes in the leakage current sampling value, and clearly defining the correspondence between the insulation resistance value and the boundary value, the final insulation assessment result is easily affected by transient fluctuations and lacks a consistent assessment basis. By extracting the stable output segment, synchronously corresponding the stable response segment, eliminating abrupt amplitude changes in the sampling value, calculating the high-voltage circuit insulation resistance value, and determining the result interval, the final measurement conclusion can be established on a data foundation with a clear structure, a clear source, and a complete calculation path. This results in high reliability of the insulation resistance measurement results, clear state judgment boundaries, and the beneficial effects of the detection conclusion directly corresponding to subsequent process handling.

[0048] Furthermore, in this embodiment, steps S1 to S4 are executed sequentially in the order described above. Step S1 first constructs an isolation injection channel and generates a test energy index; step S2 then provides a boost adjustment result based on the test energy index; step S3 generates an adjustment test signal based on the boost adjustment result; and step S4 completes the calculation of the high-voltage circuit insulation resistance value and the determination of the insulation status based on the adjustment test signal. Using this sequence, the entire measurement process is sequentially connected from initial low-disturbance injection, load level judgment, safety boundary delineation, adjustment test signal generation to insulation resistance measurement and status output. This avoids the safety risks associated with directly using a single fixed high-voltage injection and allows for graded measurement of high-voltage circuits with different insulation states under the same hardware structure.

[0049] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A safe measurement method for insulation resistance of high-voltage circuits based on coupling unit isolation and independent boost power supply, characterized in that: include: An isolated injection channel is established between the measurement end and the high-voltage circuit through a coupling unit, and the initial boost test signal is output by an independent boost power supply unit. The test energy index is generated based on the ground response voltage and leakage response current corresponding to the initial boost test signal; An insulation load withstand threshold is generated based on the test energy index, and a safe measurement constraint range is defined based on the insulation load withstand threshold; the boost adjustment result is determined based on the target range corresponding to the test energy index within the safe measurement constraint range. Based on the boost regulation results, the test voltage amplitude, boost change slope, and injection duration of the independent boost power supply unit are corrected, and an regulation test signal is applied to the high-voltage circuit through the coupling unit; after applying the regulation test signal, the regulation response voltage and regulation leakage current of the high-voltage circuit are collected; The high-voltage circuit insulation resistance value is calculated based on the adjustment test signal, the adjustment response voltage, and the adjustment leakage current, and the insulation measurement result is generated based on the high-voltage circuit insulation resistance value.

2. The method for safe measurement of insulation resistance of high-voltage circuits based on coupling unit isolation and independent boost power supply according to claim 1, characterized in that: The initial boost test signal obtained includes: The coupling unit is connected between the measuring terminal and the high-voltage circuit, so that the output terminal of the independent boost power supply unit is connected to the high-voltage circuit through the coupling unit to form an isolated injection channel; The independent boost power supply unit is controlled to apply an initial boost test signal to the high-voltage circuit via the isolation injection channel, and the ground response voltage and leakage response current of the high-voltage circuit are collected during the application of the initial boost test signal.

3. The method for safe measurement of insulation resistance of high-voltage circuits based on coupling unit isolation and independent boost power supply according to claim 2, characterized in that: The generated test energy indicators include: Based on the voltage amplitude of the initial boost test signal, the ground response voltage, and the leakage response current, the voltage and current effects of the high-voltage circuit during this injection process are determined, and a test energy index is generated based on the correspondence between the voltage and current effects.

4. The method for safe measurement of insulation resistance of high-voltage circuits based on coupling unit isolation and independent boost power supply according to claim 3, characterized in that: The defined safety measurement constraint interval includes: The test energy index is graded to obtain the load level corresponding to the current injection intensity of the high-voltage circuit; The insulation load bearing threshold corresponding to the high-voltage circuit is determined based on the load level. The insulation load bearing threshold characterizes the upper limit of the injection intensity that the high-voltage circuit can withstand during insulation measurement. The safety measurement constraint range is defined with zero as the lower limit and the insulation load bearing threshold as the upper limit.

5. The method for safe measurement of insulation resistance of high-voltage circuits based on coupling unit isolation and independent boost power supply according to claim 4, characterized in that: The determination of the boost regulation result includes: The safety measurement constraint interval is divided into a first interval, a second interval, and a third interval according to one-third and two-thirds of the insulation load bearing threshold. The first interval is a numerical interval greater than or equal to zero and less than one-third of the insulation load bearing threshold. The second interval is a numerical interval greater than or equal to one-third of the insulation load bearing threshold and less than two-thirds of the insulation load bearing threshold. The third interval is a numerical interval greater than or equal to two-thirds of the insulation load bearing threshold and less than or equal to the insulation load bearing threshold. The test energy index is matched with the first interval, the second interval, and the third interval to determine the target interval to which the test energy index belongs; When the target range of the test energy index is the first range, a boost increase result is generated; when the target range of the test energy index is the second range, a boost maintenance result is generated; when the target range of the test energy index is the third range, a boost decrease result is generated.

6. The method for safe measurement of insulation resistance of high-voltage circuits based on coupling unit isolation and independent boost power supply according to claim 5, characterized in that: The generated adjustment test signal includes: Based on the boost adjustment results, determine the corresponding test voltage amplitude correction, boost change slope correction, and injection duration correction. The output voltage amplitude of the independent boost power supply unit is adjusted according to the test voltage amplitude correction amount, the voltage rise process of the independent boost power supply unit is adjusted according to the boost change slope correction amount, and the signal holding time of the independent boost power supply unit is adjusted according to the injection duration correction amount, thereby obtaining the adjusted test signal.

7. The method for safe measurement of insulation resistance of high-voltage circuits based on coupling unit isolation and independent boost power supply according to claim 6, characterized in that: The determination of the corresponding test voltage amplitude correction, boost change slope correction, and injection duration correction includes: Obtain the boost adjustment result, and determine the adjustment direction of the test voltage amplitude, the adjustment direction of the boost change slope, and the adjustment direction of the injection duration corresponding to the boost adjustment result; When the test voltage amplitude adjustment direction is increasing, a positive test voltage amplitude correction amount is determined; when the test voltage amplitude adjustment direction is maintaining, a zero test voltage amplitude correction amount is determined; when the test voltage amplitude adjustment direction is decreasing, a reverse test voltage amplitude correction amount is determined. When the direction of the boost change slope adjustment is to increase, a positive boost change slope correction amount is determined; when the direction of the boost change slope adjustment is to maintain, a zero boost change slope correction amount is determined; when the direction of the boost change slope adjustment is to decrease, a reverse boost change slope correction amount is determined. When the direction of the injection duration adjustment is to extend, a positive injection duration correction amount is determined; when the direction of the injection duration adjustment is to maintain, a zero injection duration correction amount is determined; when the direction of the injection duration adjustment is to shorten, a reverse injection duration correction amount is determined.

8. The method for safe measurement of insulation resistance of high-voltage circuits based on coupling unit isolation and independent boost power supply according to claim 7, characterized in that: The calculation of the high-voltage circuit insulation resistance value includes: Extract the stable output segment from the adjustment test signal, and determine the test voltage amplitude corresponding to the stable output segment as the injected test voltage value; simultaneously extract the stable response segments corresponding to the adjustment response voltage and the adjustment leakage current within the stable output segment; The voltage drop to ground is determined based on the adjusted response voltage in the stable response segment, and the insulation voltage drop is determined based on the injected test voltage and the voltage drop to ground; then the insulation resistance value of the high-voltage circuit is calculated based on the insulation voltage drop and the adjusted leakage current in the stable response segment.

9. The method for safe measurement of insulation resistance of high-voltage circuits based on coupling unit isolation and independent boost power supply according to claim 8, characterized in that: The generated insulation measurement results include: The insulation resistance value of the high-voltage circuit is compared with the insulation resistance boundary value to determine the result range to which the insulation resistance value of the high-voltage circuit belongs. When the result range of the high-voltage circuit insulation resistance value is within the qualified range, a normal insulation measurement result is generated; when the result range of the high-voltage circuit insulation resistance value is within the critical range, a critical insulation measurement result is generated; when the result range of the high-voltage circuit insulation resistance value is within the abnormal range, an abnormal insulation measurement result is generated.

10. The method for safe measurement of insulation resistance of high-voltage circuits based on coupling unit isolation and independent boost power supply according to claim 8, characterized in that: The calculation of the high-voltage circuit insulation resistance value based on the insulation voltage drop value and the adjusted leakage current in the stable response segment includes: Within the stable response segment, the regulated leakage current sample values ​​with abrupt amplitude changes are removed, and the stable leakage current value is obtained based on the remaining regulated leakage current sample values. Divide the insulation voltage drop value by the stable leakage current value to obtain the insulation resistance value of the high-voltage circuit.

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