CN106997007A - Electric automobile direct-current high-voltage system insulating resistance measurement apparatus and its measuring method - Google Patents

Abstract

The invention discloses a kind of electric automobile direct-current high-voltage system insulating resistance measurement apparatus and its measuring method, sampled with a high pressure and algorithm integration module and an insulation resistance measurement circuit being connected with high pressure sampling and algorithm integration block coupled in series；High pressure sampling and algorithm integration module have a control module, and the insulation resistance measurement circuit is connected in series with the control module, for corresponding insulating resistance value at the position at the place that obtains breaking down in the batteries of electric automobile bag and failure.Present invention offer is a kind of can be precisely located the particular location of the cell broken down in battery bag, and accurately the insulation resistance value size at failure can be calculated, computational accuracy height and the fast electric automobile direct-current high-voltage insulation system insulation resistance measuring device of calculating speed.

Description

Electric automobile direct-current high-voltage system insulating resistance measurement apparatus and its measuring method

Technical field

The present invention relates to electric automobile high-voltage system insulating resistance field of measuring technique, more particularly to a kind of electric automobile are straight Flow high voltage insulation system insulation resistance measuring device and its measuring method.

Background technology

National standard GB/T 18384.1 provides that insulaion resistance is to evaluate the good and bad important references amount of electric automobile insulation situation, Designer should ensure that the ratio of insulating resistance value and electric automobile straight-flow system nominal voltage is more than 100 Ω/V, just meet safety Requirement.Existing basic insulation resistance measurement principle, by adding standard bias between positive bus-bar and shell or chassis Resistance, the measurement of correlation magnitude of voltage measured before and after circuit is incorporated to by standard bias resistance and known biasing resistor is worth to need The insulating resistance value asked.

Generally, the size of the insulation resistance value of electric automobile high-voltage dynamical system is a megaohm rank, when in battery bag Each cell in a certain cell when occurring short trouble, insulation resistance value reaches a kilo-ohm level at the failure cell Not.Now, if being calculated using existing basic insulation resistance measurement method between insulation resistance value, with actual value has certain Error, therefore basic insulation resistance measurement principle is no longer able to accurately realize and insulation resistance value size calculated.Both at home and abroad Also a variety of measuring methods for electric automobile high-voltage dynamical system insulaion resistance, the high pressure injection such as based on AC measurment Method and more traditional balanced bridge method etc..Wherein, balanced bridge method, exist it is high to the circuit precise requirements of structure, just, The shortcomings of insulating properties of negative busbar over the ground can not accurately and timely alarm when reducing simultaneously.High pressure injection method is by being pushed back to height Road injects the mode of high-voltage AC signal to detect electric automobile high-voltage dynamical system insulaion resistance, but the high pressure injection method is attached Plus high-voltage AC signal can influence the power supply quality of high direct voltage dynamical system, and the distribution capacity of high direct voltage dynamical system The magnitude of voltage of measurement can be directly affected, causes resolution ratio relatively low.Meanwhile, existing basic insulation resistance measurement method, high pressure injection Enter the measuring methods such as method and balanced bridge method, failure can not be precisely located, it is impossible to it is determined that specific occur short circuit event The particular location of the cell of barrier.

The content of the invention

The present invention exists for electric automobile high-voltage dynamical system insulation measurement method of the prior art can not essence The particular location of the cell broken down in true ground locating batteries bag, and can not be accurately big to the insulation resistance value at failure Small progress such as calculates at the defect, it is therefore intended that offer is a kind of can be precisely located the tool of the cell broken down in battery bag Body position, and accurately calculating the insulation resistance value size at failure, it is electronic that computational accuracy is high and calculating speed is fast Automobile high direct voltage insulation system insulation resistance measuring device.

Realizing the technical scheme of above-mentioned purpose is：

Electric automobile direct-current high-voltage system insulating resistance measurement apparatus of the present invention, with high pressure sampling and algorithm integration mould Block and an insulation resistance measurement circuit being connected with high pressure sampling and algorithm integration block coupled in series；

The high pressure sampling and algorithm integration module have a control module, the insulation resistance measurement circuit and the control Molding block is connected in series, for corresponding insulation at the position at the place that obtains breaking down in the batteries of electric automobile bag and failure Resistance value,

The insulation resistance measurement circuit have one in the batteries of electric automobile bag some cells be composed in series Power interface, one measurement sampling bleeder circuit, a faulty insulator resistance R_iWith an earth terminal；

The measurement sampling bleeder circuit has an anode insulaion resistance R_p, a negative terminal insulaion resistance R_n, one first standard deviation Put resistance R_0a, one second standard bias resistance R_0b, a first switch S₁, a second switch S₂, different resistance levels string successively Join a sampling resistor R of connection₁, a sampling resistor R₂, a sampling resistor R₃With a sampling resistor R₄；

The anode insulaion resistance R_pOne end and the negative terminal insulaion resistance R_nOne end is connected in series, the anode insulated electro Hinder R_pOther end anode, the first switch S respectively with the power interface₁One end be connected in series, negative terminal insulation Resistance R_nOther end negative terminal, the second switch S respectively with the power interface₂One end be connected in series；Described first opens Close S₁The other end successively with the first standard bias resistance R_0aOne end be connected in series, the first standard bias resistance R_0a The other end and the second standard bias resistance R_0bOne end be connected in series, the second standard bias resistance R_0bIt is another End and the second switch S₂The other end be connected in series；

The sampling resistor R₁One end and the first switch S₁One end be connected in series, the other end is adopted with described successively Sample resistance R₁One end, the sampling resistor R₂One end, the sampling resistor R₃One end and the sampling resistor R₄One end It is connected in series；The sampling resistor R₄The other end and the second switch S₂One end is connected in series；

The faulty insulator resistance R_iThe negative terminal of cell of the one end with being broken down in the power interface connect Connection, the other end and the anode insulaion resistance R_pOne end be connected in series；

The anode insulaion resistance R_pOne end, the first standard bias resistance R_0aThe other end and the sampling resistor R₂The other end be connected in series with the earth terminal.

The high pressure sampling and algorithm integration module, which have, to be sequentially connected in series in the insulation resistance measurement circuit and institute State the modulus turn that the analog signal for exporting the insulation resistance measurement circuit between control module is converted to data signal Parallel operation, and a data signal that the analog-digital converter is exported carry out the digital isolator of digital isolation processing.

The high pressure sampling and algorithm integration module, which have, is connected in series in the digital isolator and the analog-to-digital conversion A Serial Peripheral Interface (SPI) between device, is connected in series the serial peripheral and connects between the digital isolator and the control module Mouthful；The digital isolator is four-way digital isolator.

The high pressure sampling and algorithm integration module are steady for what is handled input voltage progress voltage stabilizing and pressure regulation with one Depressor, the output end of the voltage-stablizer is connected in series with the control module, and DC supply is provided for the control module.

The high pressure sampling and algorithm integration module have the DC/ that the output end with the voltage-stablizer is sequentially connected in series DC isolation modules and a CAN communication interface unit for realizing network service；The CAN communication interface unit can be with the control Molding block is interacted.

The insulation resistance measurement circuit is the insulation resistance measurement circuit that can be interacted with the control module.

The control module is a single-chip microcomputer.

The measuring method of the insulation resistance measuring device of the electric automobile high-voltage dynamical system of the present invention, the measuring method bag Include：

Step A, first, by the first switch S in insulation resistance measurement circuit₁With second switch S₂Disconnect；

Step B, controls insulation resistance measurement circuit to carry out Autonomous test by control module, detects whether with failure (event Barrier include sampling switch with and resistance switch it is normally closed or it is normally opened fail etc.), if insulation resistance measurement circuit has failure, then stop Only Autonomous test state, does not continue action；If insulation measurement system does not have failure, continue step C；

Step C, the positive and negative both end voltage of power interface of insulation resistance measurement circuit is measured by control module, and judges electricity Whether the positive terminal voltage of source interface is more than or equal to negative terminal voltage：

If judging that the positive terminal voltage of power interface is more than or equal to power interface negative terminal voltage, closure first switch S₁, i.e., By the first standard bias resistance R_0aThe anode of power interface is incorporated to, passes through following equation：

The position of n-th of the cell broken down in battery bag is can obtain, and obtains the monomer electricity broken down Chi Chu faulty insulator resistance R_i；Now, U₁、U₂For first switch S₁, second switch S₂When disconnecting, measurement sampling bleeder circuit To sampling resistor R₂, sampling resistor R₃Respectively sample obtained corresponding sampled voltage；U_1a' and U_2a' it is first switch S₁ Closure, second switch S₂During disconnection, measurement sampling bleeder circuit is to sampling resistor R₂, sampling resistor R₃Sampled respectively Corresponding sampled voltage；U is monomer battery voltage in known battery bag；R_n' it is negative terminal insulaion resistance R_nWith the first standard deviation Put resistance R_0bThe resistance of gained after parallel connection；

If judging that the positive terminal voltage of power interface is less than negative terminal voltage, closure second switch S₂, i.e., by the second standard deviation Put resistance R₀The negative terminal of power interface is incorporated to, passes through following equation：

The position of n-th of the cell broken down in battery bag is can obtain, and obtains the cell that breaks down The faulty insulator resistance R at place_i；U_1b' and U_2b' it is first switch S₁Disconnect, second switch S₂During closure, analog-digital converter is to sampling Resistance R₂, sampling resistor R₃Respectively sample obtained corresponding sampled voltage；R_p' it is anode insulaion resistance R_pWith the second mark Quasi- biasing resistor R_0aThe resistance of gained after parallel connection.

In one embodiment of the invention, the measuring method also includes：

Step D, insulation filtering process is carried out by control module to insulation resistance measurement circuit；

Step E, re-starts step C.

The positive effect of the present invention is：

The electric automobile direct-current high-voltage system insulating resistance measurement apparatus and its measuring method of the present invention, is sampled by high pressure And control module, digital isolator and the analog-digital converter of algorithm integration module, and insulation resistance measurement circuit, realize and survey in real time Whether amount insulation resistance measurement circuit breaks down, meanwhile, it is capable to which the cell broken down in battery bag is precisely located Particular location, and accurately the insulation resistance value size at failure can be calculated, obtain insulation resistance value and accurately can relatively 0.1% is reached, from voltage sample to when being incorporated to insulaion resistance detection of the biasing resistor again to insulation filtering and calculating process overall Between be no more than 10s, i.e., with computational accuracy is high and the characteristics of fast calculating speed.

The technique effect of the design of the present invention, concrete structure and generation is described further below with reference to accompanying drawing, with It is fully understood from the purpose of the present invention, feature and effect.

Brief description of the drawings

Fig. 1 is electric automobile direct-current high-voltage insulation system insulation resistance measuring device First Principle schematic diagram of the present invention；

Fig. 2 is the second principle schematic of electric automobile direct-current high-voltage insulation system insulation resistance measuring device of the present invention；

Fig. 3 is the measuring method principle process of electric automobile direct-current high-voltage insulation system insulation resistance measuring device of the present invention Figure.

Embodiment

With reference to Fig. 1 to Fig. 3, electric automobile direct-current high-voltage system insulating resistance measurement apparatus and its survey to the present invention Amount method is described in detail.

As shown in figure 1, the electric automobile direct-current high-voltage insulation system insulation resistance measuring device of the present embodiment, with high pressure Sampling and algorithm integration module 10 and the insulation resistance measurement circuit 20 being connected in series with high pressure sampling and algorithm integration module 10.

High pressure is sampled and algorithm integration module 10 has the voltage-stablizer for being used for that voltage stabilizing and pressure regulation processing to be carried out to input voltage 11, the DC/DC isolation modules 12 being sequentially connected in series with the output end of voltage-stablizer 11, the control general ability for realizing network service Domain network (also known as CAN, Controller Area Network) communications interface unit 13, company of being connected with the output end of voltage-stablizer 11 The control module 14 connect and corresponding insulated electro at the position for the place that obtains breaking down in batteries of electric automobile bag and failure The insulation resistance measurement circuit 20 of resistance.Being sequentially connected in series between insulation resistance measurement circuit 20 and control module 14 to insulate The analog signal that resistance measuring circuit 20 is exported is converted to the analog-digital converter 15 of data signal, and analog-digital converter 15 is exported Data signal carry out the digital isolator 16 of digital isolation processing.In one embodiment, voltage-stablizer 11 is that TLE4274-C-V50 is steady Depressor, control module 14 is single-chip microcomputer, and digital isolator 16 is ADM1401 digital isolators, and analog-digital converter 15 is MCP3204 Analog-digital converter.

Insulation resistance measurement circuit 20 is the insulation resistance measurement circuit 20 interacted with control module 14, control module 14 control insulation resistance measurement circuits 20 carry out Autonomous test etc., while insulation resistance measurement circuit 20 feeds back to Autonomous test result Control module 14, i.e., both interact.In one embodiment, the 12V DC voltages pressure regulation of input is 5V direct currents by voltage-stablizer 11 Voltage output, for providing 5V DC supplies to CAN communication interface unit 13 and control module 14.Digital isolator 16 with Serial Peripheral Interface (SPI) is connected in series between analog-digital converter 15, between digital isolator 16 and control module 14 respectively (also known as SPI, Serial Peripheral Interface) 17.In one embodiment, digital isolator 16 is four-way digital isolator 16。

As shown in Fig. 2 insulation resistance measurement circuit 20 is with corresponding with each cell in the battery bag of electric automobile Power interface 21, measurement sampling bleeder circuit 22, faulty insulator resistance R_iWith earth terminal 23.

Measurement sampling bleeder circuit 22 has anode insulaion resistance R_p, negative terminal insulaion resistance R_n, the first standard bias resistance R_0a, the second standard bias resistance R_0b, first switch S₁, second switch S₂, different resistance levels the sampling being sequentially connected in series Resistance R1, sampling resistor R2, sampling resistor R3 and sampling resistor R4.

Anode insulaion resistance R_pOne end and negative terminal insulaion resistance R_nOne end be connected in series, anode insulaion resistance R_pIt is another Anode, the first switch S of one end respectively with power interface 21₁One end be connected in series, negative terminal insulaion resistance R_nThe other end difference Negative terminal, second switch S with power interface 21₂One end be connected in series；First switch S₁The other end successively with the first standard deviation Put resistance R_0aOne end be connected in series, the first standard bias resistance R_0aThe other end and the second standard bias resistance R_0bOne end It is connected in series, the second standard bias resistance R_0bThe other end and second switch S₂The other end be connected in series.

Sampling resistor R₁One end respectively with first switch S₁One end be connected in series, the other end successively with sampling resistor R₁ One end, sampling resistor R₂One end, sampling resistor R₃One end and sampling resistor R₄One end be connected in series；Sampling resistor R₄ The other end and second switch S₂One end is connected in series；Faulty insulator resistance R_iOne end and power interface 21 in the list that breaks down The negative terminal of body battery is connected in series, the other end and anode insulaion resistance R_pOne end be connected in series.Anode insulaion resistance R_pOne End, the first standard bias resistance R_0aThe other end and sampling resistor R₂The other end be connected in series with earth terminal 23.

Wherein, V1~Vn is each monomer battery voltage in battery bag.Anode insulaion resistance R_p, negative terminal insulaion resistance R_nRespectively For anode and the negative terminal insulaion resistance over the ground of power interface 21.Wherein, U is each monomer battery voltage in known battery bag； Anode insulaion resistance R_p, negative terminal insulaion resistance R_n, the first standard bias resistance R_0a, the second standard bias resistance R_0bCorresponding resistance Value is known.

First switch S1 and second switch S2 is disconnected, positive pole voltage-to-ground V is obtained_p, negative pole voltage-to-ground V_n, and by surveying Amount sampling bleeder circuit 22 is respectively to sampling resistor R₂, sampling resistor R₃Sample obtained corresponding sampled voltage U₁、U₂。 Compare positive pole voltage-to-ground V_pWith negative pole voltage-to-ground V_nSize, if positive pole voltage-to-ground V_pMore than or equal to negative pole over the ground Voltage V_n, then first switch S is closed₁, disconnect second switch S₂When, and by measuring sampling bleeder circuit 22 respectively to sampling electricity Resistance R2, sampling resistor R3 carry out the obtained corresponding sampled voltage U of sampling_1a' and U_2a'。

The faulty insulator resistance value R of direct-current high-voltage system can be then obtained by circuit theory_iWith n-th of monomer electricity broken down Pond position n value, passes through formula (1) as follows and (2)：

Assuming that R_n∥R_0b=R_n'

It can obtain：

N is n-th of the cell position broken down in battery bag, faulty insulator resistance R_iAt failure cell Faulty insulator resistance.

Compare positive pole voltage-to-ground V_pWith negative pole voltage-to-ground V_nSize, if positive pole voltage-to-ground V_pLess than negative pole pair Ground voltage V_n, then first switch S is disconnected₁, closure second switch S₂When, and by measuring sampling bleeder circuit 22 respectively to sampling Resistance R2, sampling resistor R3 carry out the obtained corresponding sampled voltage U of sampling_1b' and U_2b'。

The faulty insulator resistance value R of direct-current high-voltage system can be then obtained by circuit theory_iWith n-th of monomer electricity broken down Pond position n value, passes through formula (3) as follows and (4)：

Assuming that R_p∥R_0a=R_p'

It can obtain：

N is n-th of the cell position broken down in battery bag, faulty insulator resistance R_iAt failure cell Faulty insulator resistance.

As shown in figure 3, the measuring method of electric automobile direct-current high-voltage insulation system insulation resistance measuring device of the present invention, tool Body is as follows：

Step1, first, by the switch S in insulation resistance measurement circuit₁With switch S₂Disconnect；

Step2, controls insulation resistance measurement circuit 20 to carry out Autonomous test, detects whether with failure by control module 14 (failure include sampling switch with and resistance switch it is normally closed or it is normally opened failure etc.), if insulation resistance measurement circuit 20 exist therefore Barrier, then stop Autonomous test state, does not continue action；If insulation measurement system 20 is without failure, continue Step3；

Step3, the positive and negative both end voltage of power interface 21 of insulation resistance measurement circuit 20 is measured by control module 14, and Judge whether the positive terminal voltage of power interface 21 is more than or equal to the negative terminal voltage of power interface 21：

If judging that the positive terminal voltage of power interface 21 is more than or equal to the negative terminal voltage of power interface 21, first switch is closed S₁, pass through following equation：

N-th of the cell broken down in battery bag is obtained, and obtains the electricity of the faulty insulator at failure cell Hinder R_i；

If judging that the positive terminal voltage of power interface 21 is less than the negative terminal voltage of power interface 21, closure second switch S₂, pass through Following equation：

N-th of the cell broken down in battery bag is obtained, and obtains the electricity of the faulty insulator at failure cell Hinder R_i；

Step4, insulation filtering process is carried out by control module 14 to insulation resistance measurement circuit 20；

Step5, re-starts Step3.

Each preferred embodiment of the invention described in detail above.It should be appreciated that one of ordinary skill in the art Just many modifications and variations can be made according to the design of the present invention without creative work.Therefore, all skills in the art Art personnel can be obtained by logical analysis, reasoning, or a limited experiment on the basis of existing technology under this invention's idea Technical scheme, all should be in the protection domain being defined in the patent claims.

Claims (9)

1. a kind of electric automobile direct-current high-voltage insulation system insulation resistance measuring device, with high pressure sampling and algorithm integration mould Block and an insulation resistance measurement circuit being connected with high pressure sampling and algorithm integration block coupled in series；

The high pressure sampling and algorithm integration module have a control module, the insulation resistance measurement circuit and the control mould Block is connected in series, for corresponding insulaion resistance at the position at the place that obtains breaking down in the batteries of electric automobile bag and failure Value, it is characterised in that；

The insulation resistance measurement circuit has an electricity that some cells are composed in series in the batteries of electric automobile bag Source interface, a measurement sampling bleeder circuit, a faulty insulator resistance R_iWith an earth terminal；

The measurement sampling bleeder circuit has an anode insulaion resistance R_p, a negative terminal insulaion resistance R_n, one first standard bias electricity Hinder R_0a, one second standard bias resistance R_0b, a first switch S₁, a second switch S₂, different resistance levels the company of being sequentially connected in series The sampling resistor R connect₁, a sampling resistor R₂, a sampling resistor R₃With a sampling resistor R₄；

The anode insulaion resistance R_pOne end and the negative terminal insulaion resistance R_nOne end is connected in series, the anode insulaion resistance R_p Other end anode, the first switch S respectively with the power interface₁One end be connected in series, the negative terminal insulated electro Hinder R_nOther end negative terminal, the second switch S respectively with the power interface₂One end be connected in series；The first switch S₁The other end successively with the first standard bias resistance R_0aOne end be connected in series, the first standard bias resistance R_0a's The other end and the second standard bias resistance R_0bOne end be connected in series, the second standard bias resistance R_0bThe other end With the second switch S₂The other end be connected in series；

The sampling resistor R₁One end and the first switch S₁One end be connected in series, the other end successively with it is described sampling electricity Hinder R₁One end, the sampling resistor R₂One end, the sampling resistor R₃One end and the sampling resistor R₄One end series connection Connection；The sampling resistor R₄The other end and the second switch S₂One end is connected in series；

The faulty insulator resistance R_iThe negative terminal of cell of the one end with being broken down in the power interface be connected in series, The other end and the anode insulaion resistance R_pOne end be connected in series；

The anode insulaion resistance R_pOne end, the first standard bias resistance R_0aThe other end and the sampling resistor R₂'s The other end is connected in series with the earth terminal.

2. electric automobile direct-current high-voltage insulation system insulation resistance measuring device as claimed in claim 1, it is characterised in that institute State high pressure sampling and algorithm integration module have be sequentially connected in series in the insulation resistance measurement circuit and the control module Between an analog signal for exporting the insulation resistance measurement circuit be converted to the analog-digital converter of data signal, and one will The data signal of the analog-digital converter output carries out the digital isolator of digital isolation processing.

3. electric automobile direct-current high-voltage insulation system insulation resistance measuring device as claimed in claim 2, it is characterised in that institute Stating high pressure sampling and algorithm integration module has one be connected in series between the digital isolator and the analog-digital converter Serial Peripheral Interface (SPI), is connected in series the Serial Peripheral Interface (SPI) between the digital isolator and the control module；The number Word isolator is four-way digital isolator.

4. electric automobile direct-current high-voltage insulation system insulation resistance measuring device as claimed in claim 1, it is characterised in that institute Stating high pressure sampling and algorithm integration module has a voltage-stablizer for being used to carry out input voltage voltage stabilizing and pressure regulation processing, described steady The output end of depressor is connected in series with the control module, and DC supply is provided for the control module.

5. electric automobile direct-current high-voltage insulation system insulation resistance measuring device as claimed in claim 4, it is characterised in that institute State the DC/DC isolation modules that there is the output end with the voltage-stablizer to be sequentially connected in series for high pressure sampling and algorithm integration module With a CAN communication interface unit for realizing network service；The CAN communication interface unit can be carried out with the control module Interaction.

6. electric automobile direct-current high-voltage insulation system insulation resistance measuring device as claimed in claim 1, it is characterised in that institute It is the insulation resistance measurement circuit that can be interacted with the control module to state insulation resistance measurement circuit.

7. electric automobile direct-current high-voltage insulation system insulation resistance measuring device as claimed in claim 1, it is characterised in that institute Control module is stated for a single-chip microcomputer.

8. a kind of insulation resistance measuring device of electric automobile high-voltage dynamical system according to any one of claims 1 to 7 Measuring method, it is characterised in that the measuring method includes：

Step A, first, by the first switch S in insulation resistance measurement circuit₁With second switch S₂Disconnect；

Step B, controls insulation resistance measurement circuit to carry out Autonomous test, detects whether with failure, if absolutely by control module There is failure in edge resistance measuring circuit, then stop Autonomous test state, not continue action；If insulation measurement system is without event Barrier, continues step C；

Step C, the positive and negative both end voltage of power interface of insulation resistance measurement circuit is measured by control module, and judges that power supply connects Whether the positive terminal voltage of mouth is more than or equal to negative terminal voltage：

If judging that the positive terminal voltage of power interface is more than or equal to power interface negative terminal voltage, closure first switch S₁, by following Formula：

$R_i=\frac{(U_{1a}^{\′}-U_1)R_1{R}_2{R}_n^{\′}}{(U_1-U_{1a}^{\′})R_n^{\′}{R}_2+R_1(U_{2a}^{\′}{R}_2-U_2{R}_n^{\′})}$

$n=\frac{\left(U_1{R}_2-U_2{R}_1\right)\left(U_{1a}^{\′}-U_1\right)R_n^{\′}}{U\left(U_1-U_{1a}^{\′}\right)R_n^{\′}{R}_2+{\mathrm{UR}}_1\left(U_{2a}^{\′}{R}_2-U_2{R}_n^{\′}\right)}+\frac{U_1}{U}$

The position of n-th of the cell broken down in battery bag is can obtain, and is obtained at the cell broken down Faulty insulator resistance R_i；Now, U₁、U₂For first switch S₁, second switch S₂During disconnection, measurement sampling bleeder circuit is to sampling Resistance R₂, sampling resistor R₃Respectively sample obtained corresponding sampled voltage；U_1a' and U_2a' it is first switch S₁Closure, the Two switch S₂During disconnection, measurement sampling bleeder circuit is to sampling resistor R₂, sampling resistor R₃Respectively carry out sample obtain it is corresponding Sampled voltage；U is monomer battery voltage in known battery bag；R_n' it is negative terminal insulaion resistance R_nWith the first standard bias resistance R_0bThe resistance of gained after parallel connection；

If judging that the positive terminal voltage of power interface is less than negative terminal voltage, closure second switch S₂, pass through following equation：

$R_i=\frac{(U_{1b}^{\′}-U_1)R_1{R}_2{R}_p^{\′}}{(U_1-U_{1b}^{\′})R_p^{\′}{R}_2+R_1(U_{2b}^{\′}{R}_2-U_2{R}_p^{\′})}$

$n=\frac{\left(U_1{R}_2-U_2{R}_1\right)\left(U_1^{\′}-U_1\right)R_p^{\′}}{U(U_1-U_{1b}^{\′})R_p^{\′}{R}_2+{\mathrm{UR}}_1\left(U_{2b}^{\′}{R}_2-U_2{R}_p^{\′}\right)}+\frac{U_1}{U}$

The position of n-th of the cell broken down in battery bag is can obtain, and is obtained at the cell that breaks down Faulty insulator resistance R_i；U_1b' and U_2b' it is first switch S₁Disconnect, second switch S₂During closure, measurement sampling bleeder circuit is to adopting Sample resistance R₂, sampling resistor R₃Respectively sample obtained corresponding sampled voltage；R_p' it is anode insulaion resistance R_pWith second Standard bias resistance R_0aThe resistance of gained after parallel connection.

9. measuring method as claimed in claim 8, it is characterised in that the measuring method also includes：

Step D, insulation filtering process is carried out by control module to insulation resistance measurement circuit；

Step E, re-starts step C.