CN109765430B

CN109765430B - Insulation impedance detection system and detection method

Info

Publication number: CN109765430B
Application number: CN201910232963.7A
Authority: CN
Inventors: 杨建敏; 韩静茹
Original assignee: Beijing Jingwei Hirain Tech Co Ltd
Current assignee: Beijing Jingwei Hirain Tech Co Ltd
Priority date: 2019-03-26
Filing date: 2019-03-26
Publication date: 2021-06-29
Anticipated expiration: 2039-03-26
Also published as: CN109765430A

Abstract

The invention discloses an insulation resistance detection system and a detection method, comprising the following steps: the processor module obtains an impedance value of the positive pole ground insulation impedance and an impedance value of the negative pole ground insulation impedance in the high-voltage system based on a first pull-up bias power supply voltage and a second pull-up bias power supply voltage output by the pull-up bias power supply acquisition module, and a first positive pole acquisition voltage, a first negative pole acquisition voltage, a second positive pole acquisition voltage and a second negative pole acquisition voltage output by the filter module, so as to determine the insulation state of the high-voltage system. According to the invention, the ripple interference in the high-voltage system is filtered by the filtering module, and the process of obtaining the impedance value of the positive pole ground insulation impedance and the impedance value of the negative pole ground insulation impedance is irrelevant to a high-voltage power supply, so that the detection precision of the insulation impedance is improved.

Description

Insulation impedance detection system and detection method

Technical Field

The invention relates to the technical field of electric automobiles, in particular to an insulation resistance detection system and a detection method.

Background

Currently, many components in electric vehicles include: the power battery, the motor, the charger, the energy recovery device, the auxiliary battery charging device, and the like all involve the insulation problem of the high-voltage electrical apparatus, and therefore, in order to improve the working reliability of the electric vehicle, the insulation resistance in the electric vehicle is generally required to be detected.

The detection methods in the prior art mainly comprise two methods, one is an alternating current signal injection method, and the other is an external resistor method. (1) The AC signal injection method comprises the following steps: and injecting a low-voltage alternating current signal with a certain frequency between the anode and the cathode of the power battery as a test signal, and measuring the feedback of the high-voltage system to obtain the insulation impedance of the power battery system. Since the test signal forms ripple interference in the high-voltage system, the ripple signal of the high-voltage system is increased, which affects the measurement accuracy of the insulation impedance, and results in misdiagnosis. (2) The external resistor method comprises the following steps: a series of resistors are connected between the anode and the cathode of the power battery, the voltage value of the insulation impedance in the on-off state is obtained by controlling the on-off state of a switch in the circuit, and the expression of the insulation impedance of the anode of the high-voltage system to the ground and the expression of the insulation impedance of the cathode of the high-voltage system to the ground are obtained by listing a state equation of the circuit. Because the two expressions relate to the high-voltage power supply, and the voltage level of the high-voltage power supply covers a wide range of 90-500V, the voltage value of the high-voltage power supply can be frequently changed in the running process of the electric automobile, so that the acquired voltage value of the high-voltage power supply is unstable, and the acquired insulation impedance is easy to have large errors or even invalid.

In summary, how to provide an insulation resistance detection system and a detection method to improve the detection accuracy of insulation resistance becomes a technical problem that needs to be solved by those skilled in the art.

Disclosure of Invention

In view of this, the invention discloses an insulation impedance detection system and a detection method, so as to filter ripple interference in a high-voltage system through a filtering module, and effectively avoid the influence on the measurement accuracy of insulation impedance and the resulting misdiagnosis caused by the increase of ripple signals; in addition, the processes of the impedance value of the positive electrode to ground insulation impedance and the impedance value of the negative electrode to ground insulation impedance obtained by the invention are independent of the high-voltage power supply, so that the error caused by the instability of the voltage value of the high-voltage power supply in the running process of the electric automobile is avoided, and the detection precision of the insulation impedance is improved.

An insulation resistance detection system comprising:

the switching device comprises a standard bias resistance switching module, a switching control module and a switching control module, wherein the positive input end of the standard bias resistance switching module is connected with the common end of a positive pole ground insulation impedance and a high-voltage power supply in a high-voltage system, and the negative input end of the standard bias resistance switching module is connected with the common end of a negative pole ground insulation impedance and the high-voltage power supply in the high-voltage system;

the positive input end of the insulation data acquisition module is connected with the positive output end of the standard bias resistance switching module, the negative input end of the insulation data acquisition module is connected with the negative output end of the standard bias resistance switching module, the power supply end of the insulation data acquisition module is connected with a pull-up bias power supply, the insulation data acquisition module is used for respectively carrying out bias conversion on the acquired positive voltage and negative voltage, outputting the biased positive voltage at the positive output end, and outputting the biased negative voltage at the negative output end;

the input end of the pull-up bias power supply acquisition module is connected with the pull-up bias power supply and is used for acquiring and outputting pull-up bias power supply voltage;

the positive output end of the filter module is used for outputting a positive collected voltage obtained after filtering the biased positive voltage; the negative input end of the filtering module is connected with the negative output end of the insulated data acquisition module, and the negative output end of the filtering module is used for outputting a negative electrode acquisition voltage obtained after the filtering of the biased negative electrode voltage;

the processor module is respectively connected with the control end of the standard bias resistor switching module, the control end of the insulation data acquisition module, the output end of the pull-up bias power acquisition module and the positive output end and the negative output end of the filtering module, and is used for determining the impedance value of the positive pole ground insulation impedance and the impedance value of the negative pole ground insulation impedance in the high-voltage system based on the pull-up bias power voltage, the positive pole acquisition voltage and the negative pole acquisition voltage, and determining the insulation state of the high-voltage system based on a preset insulation fault judgment standard, the impedance value of the positive pole ground insulation impedance and the impedance value of the negative pole ground insulation impedance.

Preferably, the standard bias resistance switching module includes: the device comprises a positive standard bias resistor, a positive bias resistor change-over switch, a negative standard bias resistor and a negative bias resistor change-over switch;

one end of the anode standard bias resistor is connected with the anode ground insulation resistance and the common end of the high-voltage power supply, and the other end of the anode standard bias resistor is grounded through the anode bias resistor change-over switch;

one end of the negative standard bias resistor is connected with the negative earth insulation resistance and the common end of the high-voltage power supply, and the other end of the negative standard bias resistor is grounded through the negative bias resistor change-over switch;

and the control end of the negative bias resistance change-over switch and the control end of the positive bias resistance change-over switch are both used as the control ends of the standard bias resistance change-over module and are connected with the processor module.

Preferably, the insulation data acquisition module includes: the device comprises a first positive electrode divider resistor, a second positive electrode divider resistor, a first negative electrode divider resistor, a second negative electrode divider resistor, a positive electrode pull-up bias resistor, a negative electrode pull-up bias resistor, a first switch and a second switch;

one end of the first switch is used as a positive input end of the insulation data acquisition module and connected with a positive output end of the standard bias resistor switching module, the other end of the first switch is grounded through the first anode divider resistor and the second anode divider resistor which are sequentially connected in series, one end of the anode pull-up bias resistor is connected with a common end of the first anode divider resistor and the second anode divider resistor, and the other end of the anode pull-up bias resistor is connected with the pull-up bias power supply;

one end of the second switch is used as a negative input end of the insulation data acquisition module and connected with a negative output end of the standard bias resistor switching module, the other end of the second switch is grounded through the first negative electrode divider resistor and the second negative electrode divider resistor which are sequentially connected in series, one end of the negative electrode pull-up bias resistor is connected with a common end of the first negative electrode divider resistor and the second negative electrode divider resistor, and the other end of the negative electrode pull-up bias resistor is connected with the pull-up bias power supply;

and the control end of the first switch and the control end of the second switch are both used as the control ends of the insulated data acquisition module and are connected with the processor module.

Preferably, the pull-up bias power supply collection module includes: the filter circuit comprises a first resistor, a second resistor and a filter capacitor;

one end of the first resistor is connected with the pull-up bias power supply, the other end of the first resistor is grounded through the second resistor, one end of the filter capacitor is connected with the common end of the first resistor and the second resistor, and the other end of the filter capacitor is grounded;

and the common end of the first resistor, the second resistor and the filter capacitor is used as the output end of the pull-up bias power supply acquisition module and is connected with the processor module.

Preferably, the filtering module includes: a positive filtering branch and a negative filtering branch;

the input end of the positive electrode filtering branch serves as the positive input end of the filtering module and is connected with the positive output end of the insulation data acquisition module, the output end of the positive electrode filtering branch serves as the positive output end of the filtering module and is connected with the processor module, and the positive electrode filtering branch is used for filtering the biased positive electrode voltage to obtain the positive electrode acquisition voltage;

the input end of the negative electrode filtering branch circuit is used as the negative input end of the filtering module and is connected with the negative output end of the insulated data acquisition module, the output end of the negative electrode filtering branch circuit is used as the negative output end of the filtering module and is connected with the processor module, and the negative electrode filtering branch circuit is used for filtering the biased negative electrode voltage to obtain the negative electrode acquisition voltage.

Preferably, the positive filtering branch comprises: the filter circuit comprises a first positive filter resistor, a second positive filter resistor, a first positive filter capacitor and a second positive filter capacitor;

one end of the first positive filter resistor is connected with the positive output end of the insulation data acquisition module, the other end of the first positive filter resistor is grounded through the first positive filter capacitor, one end of the second positive filter resistor is connected with the common end of the first positive filter resistor and the first positive filter capacitor, the other end of the second positive filter resistor is grounded through the second positive filter capacitor, and the common end of the second positive filter resistor and the second positive filter capacitor is used as the output end of the positive filter branch;

the negative filtering branch comprises: the first negative electrode filter resistor, the second negative electrode filter resistor, the first negative electrode filter capacitor and the second negative electrode filter capacitor are connected in series;

one end of the first negative electrode filter resistor is connected with the negative output end of the insulation data acquisition module, the other end of the first negative electrode filter resistor passes through the first negative electrode filter capacitor ground, one end of the second negative electrode filter resistor is connected with the first negative electrode filter resistor and the public end of the first negative electrode filter capacitor, the other end of the second negative electrode filter resistor passes through the second negative electrode filter capacitor ground, and the second negative electrode filter resistor and the public end of the second negative electrode filter capacitor serve as the output end of the negative electrode filter branch circuit.

An insulation resistance detection method is applied to a processor module in the insulation resistance detection system, and comprises the following steps:

controlling the insulation data acquisition module to work, and simultaneously controlling the standard bias resistor switching module to stop working;

respectively collecting a first pull-up bias power supply voltage output by a pull-up bias power supply collecting module, a first positive collecting voltage output by a filtering module at a positive output end and a first negative collecting voltage output by a negative output end;

comparing the magnitude relation between the first positive electrode acquisition voltage and the first negative electrode acquisition voltage to obtain a comparison result, and controlling the standard bias resistance switching module to work;

when the working time of the standard bias resistance switching module reaches a preset time, controlling a working resistor in the standard bias resistance switching module to be a negative bias resistor or a positive bias resistor based on the comparison result;

collecting a second pull-up bias power supply voltage output by the pull-up bias power supply collecting module, a second positive collecting voltage output by the filtering module at a positive output end and a second negative collecting voltage output by a negative output end again;

obtaining an impedance value of the positive pole-to-ground insulation impedance and an impedance value of the negative pole-to-ground insulation impedance in the high-voltage system based on the first pull-up bias power supply voltage, the first positive pole collection voltage, the first negative pole collection voltage, the second pull-up bias power supply voltage, the second positive pole collection voltage and the second negative pole collection voltage;

and determining the insulation state of the high-voltage system based on a preset insulation fault judgment standard, the impedance value of the positive pole to ground insulation impedance and the impedance value of the negative pole to ground insulation impedance.

Preferably, when the working time of the standard bias resistance switching module reaches a preset time, controlling the working resistance in the standard bias resistance switching module to be a negative bias resistance or a positive bias resistance based on the comparison result, specifically including:

when the working time of the standard bias resistance switching module reaches the preset time and the first positive electrode acquisition voltage is greater than the first negative electrode acquisition voltage, controlling only the positive electrode bias resistance in the standard bias resistance switching module to work;

and when the working time of the standard bias resistance switching module reaches the preset time and the first positive electrode acquisition voltage is less than the first negative electrode acquisition voltage, controlling only the negative electrode bias resistance in the standard bias resistance switching module to work.

Preferably, the obtaining the impedance value of the positive electrode-to-ground insulation impedance and the impedance value of the negative electrode-to-ground insulation impedance in the high-voltage system based on the first pull-up bias power supply voltage, the first positive electrode collection voltage, the first negative electrode collection voltage, the second pull-up bias power supply voltage, the second positive electrode collection voltage, and the second negative electrode collection voltage specifically includes:

when the first positive electrode collecting voltage is greater than the first negative electrode collecting voltage, the calculation process of the impedance value of the positive electrode-to-ground insulation impedance is as follows:

when the first positive collected voltage is greater than the first negative collected voltage, the calculation process of the impedance value of the negative ground insulation impedance is as follows:

in the formula, R_i1For the positive electrode to ground insulation resistance, U₁Collecting a voltage, U, for the first positive electrode₂Collecting a voltage, U, for the first cathode₀₁For the first pull-up bias supply voltage, U₃Collecting a voltage, U, for the second positive electrode₄Collecting voltage, U, for the second cathode₀₂For the second pull-up bias supply voltage, R₀₁Switching the standard bias resistor R of the positive electrode in the standard bias resistor module₁Is a first anode divider resistor R in the insulation data acquisition module₂A second anode divider resistor R in the insulation data acquisition module₄Is a first cathode divider resistor and R in the insulation data acquisition module₅For the second negative electrode divider resistor, R in the insulation data acquisition module₃For positive pull-up bias resistance, R in the insulation data acquisition module₆For the negative pull-up bias resistor, R, in the insulating data acquisition module_i2The negative electrode is the insulation resistance to ground.

Preferably, the obtaining of the impedance value of the positive electrode-to-ground insulation impedance and the impedance value of the negative electrode-to-ground insulation impedance in the high-voltage system based on the first pull-up bias power supply voltage, the first positive electrode collection voltage, the first negative electrode collection voltage, the second pull-up bias power supply voltage, the second positive electrode collection voltage, and the second negative electrode collection voltage specifically includes:

when the first positive electrode collecting voltage is smaller than the first negative electrode collecting voltage, the calculation process of the impedance value of the positive electrode-to-ground insulation impedance is as follows:

when the first positive collected voltage is smaller than the first negative collected voltage, the calculation process of the impedance value of the negative earth insulation impedance is as follows:

in the formula, R_i1For the positive electrode to ground insulation resistance, U₁Collecting a voltage, U, for the first positive electrode₂Collecting a voltage, U, for the first cathode₀₁Is the firstA pull-up bias supply voltage, U₃Collecting a voltage, U, for the second positive electrode₄Collecting voltage, U, for the second cathode₀₂For the second pull-up bias supply voltage, R₀₂Switching the negative standard bias resistor R in the module for the standard bias resistor₁Is a first anode divider resistor R in the insulation data acquisition module₂A second anode divider resistor R in the insulation data acquisition module₄Is a first cathode divider resistor and R in the insulation data acquisition module₅For the second negative electrode divider resistor, R in the insulation data acquisition module₃For positive pull-up bias resistance, R in the insulation data acquisition module₆For the negative pull-up bias resistor, R, in the insulating data acquisition module_i2The negative electrode is the insulation resistance to ground.

From the above technical solutions, the present invention discloses an insulation resistance detection system and a detection method, including: the processor module controls the insulated data acquisition module to work, controls the standard biased resistance switching module to stop working, respectively acquires a first pull-up biased power supply voltage output by the pull-up biased power supply acquisition module, a first positive electrode acquisition voltage output by the filter module and a first negative electrode acquisition voltage, controls the standard biased resistance switching module to work for a preset time after comparing the magnitude relation between the first positive electrode acquisition voltage and the first negative electrode acquisition voltage, controls the working resistance in the standard biased resistance switching module to be a negative electrode biased resistance or a positive electrode biased resistance based on the magnitude comparison result, and acquires a second pull-up biased power supply voltage output by the pull-up biased power supply acquisition module, a second positive electrode acquisition voltage output by the filter module and a second negative electrode acquisition voltage again, therefore, based on the first upper pulling bias power supply voltage, the first anode collecting voltage, the first cathode collecting voltage, the second upper pulling bias power supply voltage, the second anode collecting voltage and the second cathode collecting voltage, the impedance value of the anode to ground insulation impedance and the impedance value of the cathode to ground insulation impedance in the high-voltage system are obtained, and the insulation state of the high-voltage system is further determined. Compared with the traditional scheme, the invention adds the pull-up bias power supply acquisition module and the filtering module, and filters the ripple interference in the high-voltage system through the filtering module, thereby effectively avoiding the influence on the measurement precision of the insulation impedance and the error diagnosis caused by the increase of the ripple signal; in addition, the processes of the impedance value of the positive electrode to ground insulation impedance and the impedance value of the negative electrode to ground insulation impedance obtained by the invention are independent of the high-voltage power supply, so that the error caused by the instability of the voltage value of the high-voltage power supply in the running process of the electric automobile is avoided, and the detection precision of the insulation impedance is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the disclosed drawings without creative efforts.

Fig. 1 is a block diagram of an insulation resistance detection system of a high voltage system according to an embodiment of the present invention;

FIG. 2 is a circuit diagram of an insulation resistance detection circuit of a high voltage system according to an embodiment of the present invention;

FIG. 3 is a circuit diagram of the insulation resistance detection of a high voltage system according to an embodiment of the present invention;

FIG. 4 is a circuit diagram of the insulation resistance detection of a high voltage system according to an embodiment of the present invention;

FIG. 5 is a circuit diagram of the insulation resistance detection of a high voltage system according to an embodiment of the present invention;

FIG. 6 is a circuit diagram of the insulation resistance detection of a high voltage system according to an embodiment of the present invention;

fig. 7 is a flowchart of an insulation resistance detection method for a high voltage system according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The embodiment of the invention discloses an insulation resistance detection system and a detection method, which comprises the following steps: the processor module controls the insulated data acquisition module to work, controls the standard biased resistance switching module to stop working, respectively acquires a first pull-up biased power supply voltage output by the pull-up biased power supply acquisition module, a first positive electrode acquisition voltage output by the filter module and a first negative electrode acquisition voltage, controls the standard biased resistance switching module to work for a preset time after comparing the magnitude relation between the first positive electrode acquisition voltage and the first negative electrode acquisition voltage, controls the working resistance in the standard biased resistance switching module to be a negative electrode biased resistance or a positive electrode biased resistance based on the magnitude comparison result, and acquires a second pull-up biased power supply voltage output by the pull-up biased power supply acquisition module, a second positive electrode acquisition voltage output by the filter module and a second negative electrode acquisition voltage again, therefore, based on the first upper pulling bias power supply voltage, the first anode collecting voltage, the first cathode collecting voltage, the second upper pulling bias power supply voltage, the second anode collecting voltage and the second cathode collecting voltage, the impedance value of the anode to ground insulation impedance and the impedance value of the cathode to ground insulation impedance in the high-voltage system are obtained, and the insulation state of the high-voltage system is further determined. Compared with the traditional scheme, the invention adds the pull-up bias power supply acquisition module and the filtering module, and filters the ripple interference in the high-voltage system through the filtering module, thereby effectively avoiding the influence on the measurement precision of the insulation impedance and the error diagnosis caused by the increase of the ripple signal; in addition, the processes of the impedance value of the positive electrode to ground insulation impedance and the impedance value of the negative electrode to ground insulation impedance obtained by the invention are independent of the high-voltage power supply, so that the error caused by the instability of the voltage value of the high-voltage power supply in the running process of the electric automobile is avoided, and the detection precision of the insulation impedance is improved.

Referring to fig. 1, a block diagram of an insulation resistance detection system of a high voltage system according to an embodiment of the present invention, the insulation resistance detection system being connected to the high voltage system, referring to fig. 2, an insulation resistance detection circuit diagram of a high voltage system according to an embodiment of the present invention, the high voltage system 10 includes: high-voltage power supply U, positive pole insulation resistance to ground R_i1Negative electrode to ground insulation resistance R_i2Positive electrode to ground Y capacitor C_i1And a negative electrode to ground Y capacitor C_i2Positive electrode to ground insulation resistance R_i1And a positive electrode to ground Y capacitor C_i1Connected in parallel between the positive pole of the high-voltage power supply U and the ground, and the negative pole is insulated against the ground_i2And a negative electrode to ground Y capacitor C_i2And is connected between the negative pole of the high-voltage power supply U and the ground in parallel. The positive electrode insulation resistance to ground R_i1And negative electrode to ground insulation resistance R_i2Namely the measured insulation impedance, and the Y capacitor is also the safety capacitor.

The insulation resistance detection system includes: the device comprises a standard bias resistor switching module 11, an insulation data acquisition module 12, a pull-up bias power supply acquisition module 13, a filtering module 14 and a processor module 15;

wherein:

the positive input end of the standard bias resistor switching module 11 and the positive pole-to-ground insulation resistance R in the high-voltage system_i1The negative input end of the standard bias resistance switching module 11 is connected with the common end of the high-voltage power supply U, and the negative pole-to-ground insulation resistance R in the high-voltage system_i2And the common end of the high-voltage power supply U.

Referring to fig. 2, the standard offset resistance switching module 11 may specifically include: positive electrode standard bias resistor R₀₁Positive bias resistance change-over switch S₃And a negative standard bias resistor R₀₂And a negative bias resistance change-over switch S₄；

Positive electrode standard bias resistor R₀₁One end of which is connected with the anode-to-ground insulation resistance R_i1And a common terminal, positive standard bias resistor R of a high-voltage power supply U₀₁The other end of (A) is passingPole-bias resistance change-over switch S₃Grounding;

negative standard bias resistor R₀₂One end of which is connected with the negative electrode to ground insulation resistance R_i2And a common terminal and a cathode standard bias resistor R of a high-voltage power supply U₀₂The other end of the switch is grounded through a negative bias resistance change-over switch S₄；

Negative bias resistance change-over switch S₄Control terminal and positive bias resistance change-over switch S₃The control terminals of the switching module 11 are all used as the control terminals of the standard bias resistance switching module 11, are connected with the processor module 15, and can execute corresponding on and off operations according to on and off signals sent by the processor module 15.

The positive input end of the insulation data acquisition module 12 is connected with the positive output end of the standard bias resistance switching module 11, the negative input end of the insulation data acquisition module 12 is connected with the negative output end of the standard bias resistance switching module 11, the power supply end of the insulation data acquisition module 12 is connected with an upward-pulling bias power supply (not shown in fig. 1), the insulation data acquisition module 12 is used for respectively carrying out bias conversion on the acquired positive voltage and negative voltage, the biased positive voltage is output at the positive output end, and the biased negative voltage is output at the negative output end.

Referring to fig. 2, the insulation data acquisition module 12 may specifically include: a first positive divider resistor R₁A second positive voltage-dividing resistor R₂A first negative voltage-dividing resistor R₄A second negative voltage dividing resistor R₅Positive pole pull-up bias resistor R₃Cathode pull-up bias resistor R₆A first switch S₁And a second switch S₂；

First switch S₁Is used as the positive input end of the insulation data acquisition module 12 and is connected with the positive output end of the standard bias resistor switching module 11, specifically with the positive standard bias resistor R₀₁A first switch S connected with the common terminal of the high-voltage power supply U₁The other end of the first positive electrode is connected with a first positive electrode divider resistor R in series in sequence₁And a second positive voltage-dividing resistor R₂Grounded, positive pull-up bias resistor R₃One end of is connected with the firstPositive electrode divider resistor R₁And a second positive voltage-dividing resistor R₂The common terminal, the anode pull-up bias resistor R₃The other end of the switch is connected with a pull-up bias power supply VCC;

a second switch S₂Is connected with the negative output end of the standard bias resistor switching module 11 as the negative input end of the insulation data acquisition module 12, specifically with the negative standard bias resistor R₀₂A second switch S connected with the common terminal of the high-voltage power supply U₂The other end of the first negative electrode is connected with a first negative electrode divider resistor R in series in sequence₄And a second negative voltage-dividing resistor R₅Grounded and negative pole pull-up bias resistor R₆One end of the first negative electrode is connected with a first negative electrode divider resistor R₄And a second negative voltage-dividing resistor R₅Common terminal, negative pull-up bias resistor R₆The other end of the switch is connected with a pull-up bias power supply VCC;

first switch S₁And a second switch S₂The control ends of the insulated data acquisition module 12 are used as control ends of the insulated data acquisition module 12, are connected with the processor module 15, and can execute corresponding on and off operations according to on and off signals sent by the processor module 15.

It should be noted that, in order to improve the data acquisition precision, the standard bias resistor R of the positive electrode in the standard bias resistor switching module 11₀₁And a negative standard bias resistor R₀₂And a first positive divider resistor R in the insulation data acquisition module 12₁A second positive voltage-dividing resistor R₂A first negative voltage-dividing resistor R₄A second negative voltage dividing resistor R₅Positive pole pull-up bias resistor R₃And a negative pull-up bias resistor R₆High-precision bias resistors are adopted, and specifically, bias resistors with the precision of more than 0.1% can be adopted.

The input end of the pull-up bias power supply acquisition module 13 is connected to a pull-up bias power supply VCC for acquiring and outputting a pull-up bias power supply voltage.

Referring to fig. 2, the pull-up bias power collecting module 13 may specifically include: a first resistor R₁₁A second resistor R₁₂And a filter capacitor C₅；

A first resistor R₁₁Is connected to a pull-up bias power source VCC, a first resistor R₁₁Is passed through a second resistor R₁₂Grounding, filter capacitance C₅One end of which is connected with a first resistor R₁₁And a second resistor R₁₂Common terminal of, filter capacitor C₅The other end of the first and second electrodes is grounded;

a first resistor R₁₁A second resistor R₁₂And a filter capacitor C₅The common terminal of the voltage source module is used as the output terminal of the pull-up bias power source acquisition module 13 and is connected with the processor module 15, and the acquired pull-up bias power source voltage is output to the processor module 15.

The positive input end of the filter module 14 is connected with the positive output end of the insulation data acquisition module 12, and the positive output end of the filter module 14 is used for outputting a positive electrode acquisition voltage obtained by filtering the biased positive electrode voltage; the negative input end of the filtering module 14 is connected to the negative output end of the insulated data acquisition module 12, and the negative output end of the filtering module 14 is used for outputting a negative electrode acquisition voltage obtained after filtering the biased negative electrode voltage.

Referring to fig. 2, the filtering module 14 may specifically include: a positive filtering branch and a negative filtering branch;

the input end of the positive filtering branch is used as the positive input end of the filtering module 14 and connected with the positive output end of the insulation data acquisition module 12, the output end of the positive filtering branch is used as the positive output end of the filtering module 14 and connected with the processor module 15, and the positive filtering branch is used for filtering the biased positive voltage to obtain a positive acquisition voltage;

the input end of the negative electrode filtering branch serves as the negative input end of the filtering module 14 and is connected with the negative output end of the insulated data acquisition module 12, the output end of the negative electrode filtering branch serves as the negative output end of the filtering module 14 and is connected with the processor module 15, and the negative electrode filtering branch is used for filtering biased negative electrode voltage to obtain negative electrode acquisition voltage.

It should be noted that the positive filtering branch and the negative filtering branch may adopt a one-stage filtering circuit or a multi-stage filtering circuit, and in this embodiment, the positive filtering branch and the negative filtering branch are preferably two-stage filtering circuits.

When the positive filtering branch and the negative filtering branch are both the secondary filtering circuit, referring to fig. 2, the positive filtering branch may include: a first positive filter resistor R₇A second positive filter resistor R₈A first positive filter capacitor C₁And a second positive filter capacitor C₂；

Wherein, the first positive filter resistor R₇Is connected with the positive output end of the insulation data acquisition module 12, in particular to the first positive divider resistor R₁A second positive voltage-dividing resistor R₂And a positive pull-up bias resistor R₃Is connected to the first positive filter resistor R₇The other end of the first positive filter capacitor C₁Grounded, second positive filter resistor R₈One end of the first positive filter resistor R is connected with the first positive filter resistor R₇And a first positive filter capacitor C₁A second positive filter resistance R₈The other end of the first positive filter capacitor C passes through a second positive filter capacitor C₂Grounded, second positive filter resistor R₈And a second positive filter capacitor C₂The common terminal of the filter is used as the output terminal of the positive filtering branch circuit;

the negative filtering branch may include: first negative filter resistor R₉A second negative filter resistor R₁₀A first negative filter capacitor C₃And a second negative filter capacitor C₄；

Wherein, the first cathode filter resistor R₉Is connected with the negative output end of the insulated data acquisition module 12, in particular to the first negative divider resistor R₄A second negative voltage dividing resistor R₅And a negative pull-up bias resistor R₆Is connected with the common terminal of the first negative filter resistor R₉The other end of the first capacitor passes through a first negative filter capacitor C₃Grounded, second negative filter resistor R₁₀One end of the first negative filter resistor R is connected with the first negative filter resistor R₉And a first negative filter capacitor C₄A second negative filter resistance R₁₀The other end of the first capacitor passes through a second cathode filter capacitor C₄Grounded, second negative filter resistor R₁₀And a second negative filter capacitor C₄As the output terminal of the negative filtering branch.

The processor module 15 is respectively connected with the control end of the standard bias resistor switching module 11, the control end of the insulation data acquisition module 12, the output end of the pull-up bias power acquisition module 13 and the positive output end and the negative output end of the filter module 14, and the processor module 15 is used for determining the impedance value of the positive pole ground insulation impedance and the impedance value of the negative pole ground insulation impedance in the high-voltage system based on the pull-up bias power voltage output by the pull-up bias power acquisition module 13, the positive pole acquisition voltage output by the positive output end of the filter module 14 and the negative pole acquisition voltage output by the negative output end of the filter module 14, and determining the insulation state of the high-voltage system based on the preset insulation fault judgment standard, the impedance value of the positive pole ground insulation impedance and the impedance value of the negative pole ground insulation impedance.

For convenient understanding, the invention provides a specific working process of the insulation resistance detection system, which comprises the following steps:

in the initial state, the processor module 15 controls the insulating data acquisition module 12 to work, and controls the standard bias resistor switching module 11 to stop working at the same time, namely the processor module 15 switches the first switch S in the insulating data acquisition module 12 to₁And a second switch S₂Sending a switch-on signal to make the first switch S₁And a second switch S₂Are all closed, and a first anode divider resistor R₁A second positive voltage-dividing resistor R₂A first negative voltage-dividing resistor R₄And a second negative voltage-dividing resistor R₅Are all accessed, so that the insulation data acquisition module 12 works; while switching the switch S to the positive bias resistance in the standard bias resistance switching module 11₃And a negative bias resistance change-over switch S₄Sending a switch-off signal to switch the positive bias resistor to the switch S₃And a negative bias resistance change-over switch S₄The circuit diagram of the insulation resistance detection circuit of the high-voltage system is shown in fig. 3.

Through a pull-up bias power supply VCC and a positive pull-up bias resistor R₃Performing bias conversion on the anode voltage output by the insulation data acquisition module 12 to obtain a biased anode voltage; biasing a power supply VCC by pull-upAnd a negative pull-up bias resistor R₆And performing offset conversion on the cathode voltage output by the insulation data acquisition module 12 to obtain the offset cathode voltage.

The positive filtering branch in the filtering module 14 includes: a first positive filter resistor R₇A second positive filter resistor R₈A first positive filter capacitor C₁And a second positive filter capacitor C₂Filtering the biased anode voltage to obtain a first anode collecting voltage U₁(ii) a The negative filtering branch in the filtering module 14 includes: first negative filter resistor R₉A second negative filter resistor R₁₀A first negative filter capacitor C₃And a second negative filter capacitor C₄Filtering the biased cathode voltage to obtain a first cathode acquisition voltage U₂. Meanwhile, the pull-up bias power collection module 13 passes through the first resistor R₁₁A second resistor R₁₂And a filter capacitor C₅Collecting a first pull-up bias power supply voltage U₀₁。

The processor module 15 compares the first positive collected voltage U₁And a first negative electrode collecting voltage U₂The comparison result is obtained, and meanwhile, the processor module 15 controls the standard bias resistance switching module 11 to work, namely, the processor module 15 switches the switch S to the positive bias resistance in the standard bias resistance switching module 11₃And a negative bias resistance change-over switch S₄Sending a switch-on signal to switch the positive bias resistor to the switch S₃And a negative bias resistance change-over switch S₄Are all closed, and have positive standard bias resistance R₀₁And a negative standard bias resistor R₀₂Fig. 4 shows an insulation resistance detection circuit diagram of the high-voltage system at this time. Keeping the state for a preset time T, wherein the value of the preset time T is determined according to the positive pole of the high-voltage system to the ground Y capacitor C_i1And a negative electrode to ground Y capacitor C_i2And (6) calibrating.

When the working time of the standard bias resistance switching module 11 reaches the preset time T, acquiring the voltage U according to the first positive electrode₁And a first negative electrode collecting voltage U₂Comparing the magnitudes of the positive and negative electrodes, and performing positive standard biasResistance R₀₁And a negative standard bias resistor R₀₂The handover of (2).

If U is₁>U₂The processor module 15 then switches the switch S to the negative bias resistance₄Sending a turn-off signal to cause the negative bias resistor to switch the switch S₄Disconnecting the negative standard bias resistor R₀₂The operation is stopped, and the insulation resistance detection circuit diagram of the high voltage system at this time is shown in fig. 5.

If U is₁＜U₂The processor module 15 then biases the resistance-switching switch S to the positive pole₃Sending a turn-off signal to cause the positive bias resistor to switch the switch S₃Disconnecting the positive standard bias resistor R₀₁The operation is stopped, and the insulation resistance detection circuit diagram of the high voltage system at this time is shown in fig. 6.

After finishing the anode standard bias resistance R₀₁And a negative standard bias resistor R₀₂After the switching, the processor module 15 collects the second pull-up bias power supply voltage U output by the pull-up bias power supply collection module 13 again₀₂The second positive collecting voltage U output by the filter module 14 at the positive output end₃And a second negative collecting voltage U output at the negative output terminal₄。

The processor module 15 collects the voltage U based on the collected first positive electrode₁A first negative electrode collecting voltage U₂A first pull-up bias power supply voltage U₀₁The second positive electrode collects voltage U₃A second negative electrode collecting voltage U₄And a second pull-up bias supply voltage U₀₂And a positive standard bias resistor R₀₁And a negative standard bias resistor R₀₂A first positive divider resistor R₁A second positive voltage-dividing resistor R₂A first negative voltage-dividing resistor R₄A second negative voltage dividing resistor R₅Positive pole pull-up bias resistor R₃Cathode pull-up bias resistor R₆The positive electrode-to-ground insulation resistance R is listed_i1And negative electrode to ground insulation resistance R_i2According to the state equation of the relevant circuit, the positive pole earth insulation resistance R is calculated_i1Resistance value of (3) and negative electrode-to-ground insulation resistance R_i2Is connected with a resistorResistance value.

Positive electrode insulation resistance to ground R_i1And negative electrode to ground insulation resistance R_i2The relevant circuit state equation of (2) is as follows:

(1)U₁>U₂(i.e., R)_i1＞R_i2)

(2)U₁＜U₂(i.e., R)_i1＜R_i2)

The processor module 15 calculates the positive electrode-to-ground insulation resistance R_i1Resistance value of (3) and negative electrode-to-ground insulation resistance R_i2After the resistance value is obtained, the positive electrode-to-ground insulation resistance R can be determined based on the preset insulation fault judgment standard_i1Resistance value of (3) and negative electrode-to-ground insulation resistance R_i2The impedance value of the high voltage system. In particular, according to the IEC60147-1 Current guidelines for the effects on humans and livestock part 1: the general part shows that the current requirement of the harmless overcurrent capacity of the human body is less than 10mA (DC) or less than 2mA (AC), the corresponding insulation resistance is more than 100 omega/V or more than 500 omega/V, and the R is determined_i1<U500 Ω or R_i2<And U is 500 omega, reporting the insulation fault, wherein U is the voltage of the high-voltage system.

In summary, the insulation resistance detection system disclosed in the present invention includes: the processor module 15 controls the insulated data acquisition module 12 to work, and controls the standard biased resistance switching module 11 to stop working, and respectively acquires a first pull-up biased power supply voltage output by the pull-up biased power supply acquisition module 13, a first positive electrode acquisition voltage output by the filter module 14 and a first negative electrode acquisition voltage, after comparing the magnitude relation between the first positive electrode acquisition voltage and the first negative electrode acquisition voltage, the standard biased resistance switching module 11 is controlled to work for a preset time, then the working resistance in the standard biased resistance switching module 11 is controlled to be a negative electrode biased resistance or a positive electrode biased resistance based on the magnitude comparison result, and a second pull-up biased power supply voltage output by the pull-up biased power supply acquisition module is acquired again, The second positive electrode collecting voltage and the second negative electrode collecting voltage output by the filtering module 14 are obtained based on the first pull-up bias power supply voltage, the first positive electrode collecting voltage, the first negative electrode collecting voltage, the second pull-up bias power supply voltage, the second positive electrode collecting voltage and the second negative electrode collecting voltage, so that the impedance value of the positive electrode ground insulation impedance and the impedance value of the negative electrode ground insulation impedance in the high-voltage system are obtained, and the insulation state of the high-voltage system is determined. Compared with the traditional scheme, the invention adds the pull-up bias power supply acquisition module 13 and the filtering module 14, and filters the ripple interference in the high-voltage system through the filtering module 14, thereby effectively avoiding the influence on the measurement precision of the insulation impedance and the error diagnosis caused by the increase of the ripple signal; in addition, the processes of the impedance value of the positive electrode to ground insulation impedance and the impedance value of the negative electrode to ground insulation impedance obtained by the invention are independent of the high-voltage power supply, so that the error caused by the instability of the voltage value of the high-voltage power supply in the running process of the electric automobile is avoided, and the detection precision of the insulation impedance is improved.

In addition, after the first pull-up bias power supply voltage, the first anode collecting voltage and the first cathode collecting voltage are collected, the standard bias resistance switching module 11 is closed while the magnitude relation between the first anode collecting voltage and the first cathode collecting voltage is compared, so that the distributed capacitance of the system is charged, and then the anode standard bias resistance and the cathode standard bias resistance are switched according to the magnitude comparison result between the first anode collecting voltage and the first cathode collecting voltage. The step reduces the charging and discharging time of the distributed capacitance of the system, thereby further reducing the sampling time of the insulation data.

In the insulation data acquisition module 12, the negative sampling data can be converted into the positive sampling data through the pull-up bias power supply and the negative pull-up bias resistor, so that the processor module 15 can directly read the sampling data without acquiring the sampling data after the AD conversion of negative pressure resistance, thereby further reducing the system cost.

Corresponding to the system embodiment, the invention also discloses an insulation resistance detection method.

Referring to fig. 7, a flowchart of an insulation resistance detection method according to an embodiment of the present invention is applied to a processor module in the insulation resistance detection system, and includes the steps of:

s101, controlling an insulation data acquisition module to work, and controlling a standard bias resistance switching module to stop working at the same time;

step S102, respectively collecting a first pull-up bias power supply voltage output by a pull-up bias power supply collecting module, a first positive collecting voltage output by a filtering module at a positive output end and a first negative collecting voltage output by a negative output end;

s103, comparing the magnitude relation of the first positive electrode collecting voltage and the first negative electrode collecting voltage to obtain a comparison result, and controlling the standard bias resistor switching module to work;

step S104, when the working time of the standard bias resistance switching module reaches the preset time, controlling the working resistance in the standard bias resistance switching module to be a negative bias resistance or a positive bias resistance based on the comparison result;

specifically, when the working time of the standard bias resistor switching module reaches a preset time and the first positive electrode acquisition voltage is greater than the first negative electrode acquisition voltage, only the positive electrode bias resistor in the standard bias resistor switching module is controlled to work;

and when the working time of the standard bias resistor switching module reaches the preset time and the first positive electrode acquisition voltage is less than the first negative electrode acquisition voltage, controlling only the negative electrode bias resistor in the standard bias resistor switching module to work.

When the working time of the standard bias resistor switching module reaches the preset time and the first positive electrode collecting voltage is equal to the first negative electrode collecting voltage, only the positive electrode bias resistor in the standard bias resistor switching module can be controlled to work, or only the negative electrode bias resistor in the standard bias resistor switching module can be controlled to work, which is specifically determined according to actual needs, and the invention is not limited herein.

Step S105, collecting a second pull-up bias power supply voltage output by the pull-up bias power supply collecting module, a second positive collecting voltage output by the filtering module at the positive output end and a second negative collecting voltage output by the negative output end again;

step S106, obtaining the impedance value of the positive pole-to-ground insulation impedance and the impedance value of the negative pole-to-ground insulation impedance in the high-voltage system based on the first pull-up bias power supply voltage, the first positive pole collection voltage, the first negative pole collection voltage, the second pull-up bias power supply voltage, the second positive pole collection voltage and the second negative pole collection voltage;

it should be noted that, please refer to the corresponding portion of the system embodiment for the specific implementation process of step S106, which is not described herein again.

And S107, determining the insulation state of the high-voltage system based on the preset insulation fault judgment standard, the impedance value of the positive electrode ground insulation impedance and the impedance value of the negative electrode ground insulation impedance.

In particular, according to the IEC60147-1 Current guidelines for the effects on humans and livestock part 1: the general part shows that the current requirement of the harmless overcurrent capacity of the human body is less than 10mA (DC) or less than 2mA (AC), the corresponding insulation resistance is more than 100 omega/V or more than 500 omega/V, and the R is determined_i1<U500 Ω or R_i2<And U is 500 omega, reporting the insulation fault, wherein U is the voltage of the high-voltage system.

In summary, in the insulation impedance detection method disclosed by the invention, the processor module controls the insulation data acquisition module to work, controls the standard bias resistance switching module to stop working, and respectively acquires the first pull-up bias power supply voltage output by the pull-up bias power supply acquisition module, the first positive electrode acquisition voltage output by the filter module and the first negative electrode acquisition voltage, controls the standard bias resistance switching module to work for a preset time after comparing the magnitude relation between the first positive electrode acquisition voltage and the first negative electrode acquisition voltage, controls the working resistor in the standard bias resistance switching module to be the negative electrode bias resistor or the positive electrode bias resistor based on the magnitude comparison result, and acquires the second pull-up bias power supply voltage output by the pull-up bias power supply acquisition module, the second positive electrode acquisition voltage output by the filter module and the second negative electrode acquisition voltage again, thereby obtaining the first pull-up bias power supply voltage, the second pull-up bias power supply voltage, the first positive electrode acquisition voltage and the second negative electrode acquisition voltage based on the first, The first positive electrode collecting voltage, the first negative electrode collecting voltage, the second pull-up bias power supply voltage, the second positive electrode collecting voltage and the second negative electrode collecting voltage are obtained to obtain the impedance value of the positive electrode to ground insulation impedance and the impedance value of the negative electrode to ground insulation impedance in the high-voltage system, and then the insulation state of the high-voltage system is determined. Compared with the traditional scheme, the invention adds the pull-up bias power supply acquisition module and the filtering module, and filters the ripple interference in the high-voltage system through the filtering module, thereby effectively avoiding the influence on the measurement precision of the insulation impedance and the error diagnosis caused by the increase of the ripple signal; in addition, the processes of the impedance value of the positive electrode to ground insulation impedance and the impedance value of the negative electrode to ground insulation impedance obtained by the invention are independent of the high-voltage power supply, so that the error caused by the instability of the voltage value of the high-voltage power supply in the running process of the electric automobile is avoided, and the detection precision of the insulation impedance is improved.

It should be noted that, for details of the working principle of each step in the method embodiment, reference is made to the corresponding part of the system embodiment, which is not described herein again.

Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An insulation resistance detection system, comprising:

the processor module is respectively connected with the control end of the standard bias resistor switching module, the control end of the insulation data acquisition module, the output end of the pull-up bias power acquisition module and the positive output end and the negative output end of the filtering module, and is used for determining the impedance value of the positive pole ground insulation impedance and the impedance value of the negative pole ground insulation impedance in the high-voltage system based on the pull-up bias power voltage, the positive pole acquisition voltage and the negative pole acquisition voltage, and determining the insulation state of the high-voltage system based on a preset insulation fault judgment standard, the impedance value of the positive pole ground insulation impedance and the impedance value of the negative pole ground insulation impedance;

wherein the filtering module comprises: a positive filtering branch and a negative filtering branch;

2. The insulation resistance detection system of claim 1, wherein the standard bias resistance switching module comprises: the device comprises a positive standard bias resistor, a positive bias resistor change-over switch, a negative standard bias resistor and a negative bias resistor change-over switch;

3. The insulation resistance detection system of claim 1, wherein the insulation data acquisition module comprises: the device comprises a first positive electrode divider resistor, a second positive electrode divider resistor, a first negative electrode divider resistor, a second negative electrode divider resistor, a positive electrode pull-up bias resistor, a negative electrode pull-up bias resistor, a first switch and a second switch;

4. The insulation resistance detection system of claim 1, wherein the pull-up bias power harvesting module comprises: the filter circuit comprises a first resistor, a second resistor and a filter capacitor;

5. The insulation resistance detection system of claim 1, wherein the positive filter branch comprises: the filter circuit comprises a first positive filter resistor, a second positive filter resistor, a first positive filter capacitor and a second positive filter capacitor;

6. An insulation resistance detection method applied to the insulation resistance detection system of claim 1, comprising:

7. The insulation resistance detection method according to claim 6, wherein when the operating time of the standard bias resistance switching module reaches a preset time, controlling the resistor operated in the standard bias resistance switching module to be a negative bias resistor or a positive bias resistor based on the comparison result, specifically comprising:

8. The insulation resistance detection method according to claim 6, wherein the obtaining of the impedance value of the positive electrode-to-ground insulation resistance and the impedance value of the negative electrode-to-ground insulation resistance in the high voltage system based on the first pull-up bias power supply voltage, the first positive electrode collected voltage, the first negative electrode collected voltage, the second pull-up bias power supply voltage, the second positive electrode collected voltage, and the second negative electrode collected voltage specifically comprises:

in the formula, R_i1For the positive electrode to ground insulation resistance, U₁Collecting a voltage, U, for the first positive electrode₂Collecting a voltage, U, for the first cathode₀₁For the first pull-up bias supply voltage, U₃Collecting a voltage, U, for the second positive electrode₄Collecting voltage, U, for the second cathode₀₂For the second pull-up bias supply voltage, R₀₁Switching the standard bias resistor R of the positive electrode in the standard bias resistor module₁Is a first anode divider resistor R in the insulation data acquisition module₂A second anode divider resistor R in the insulation data acquisition module₄Is the first in the insulated data acquisition moduleA negative electrode divider resistor R₅For the second negative electrode divider resistor, R in the insulation data acquisition module₃For positive pull-up bias resistance, R in the insulation data acquisition module₆For the negative pull-up bias resistor, R, in the insulating data acquisition module_i2The negative electrode is the insulation resistance to ground.

9. The insulation resistance detection method according to claim 6, wherein the obtaining of the impedance value of the positive electrode-to-ground insulation resistance and the impedance value of the negative electrode-to-ground insulation resistance in the high voltage system based on the first pull-up bias power supply voltage, the first positive electrode collected voltage, the first negative electrode collected voltage, the second pull-up bias power supply voltage, the second positive electrode collected voltage, and the second negative electrode collected voltage specifically comprises:

in the formula, R_i1For the positive electrode to ground insulation resistance, U₁Collecting a voltage, U, for the first positive electrode₂Collecting a voltage, U, for the first cathode₀₁For the first pull-up bias supply voltage, U₃Collecting a voltage, U, for the second positive electrode₄Collecting voltage, U, for the second cathode₀₂For the second pull-up bias supply voltage, R₀₂Switching the negative standard bias resistor R in the module for the standard bias resistor₁Is a first anode divider resistor R in the insulation data acquisition module₂A second anode divider resistor R in the insulation data acquisition module₄Is a first cathode divider resistor and R in the insulation data acquisition module₅For the second negative electrode divider resistor, R in the insulation data acquisition module₃For positive pull-up bias resistance, R in the insulation data acquisition module₆For the negative pull-up bias resistor, R, in the insulating data acquisition module_i2The negative electrode is the insulation resistance to ground.