CN102508038A - Insulating detection system and method of power battery for electric automobile - Google Patents

Abstract

The invention provides an insulating detection system and method of a power battery for an electric automobile, which can be used for detecting insulting resistance values of a high-voltage anode and a high-voltage cathode of a power storage battery to an automobile body ground. The system is applicable to a high-voltage insulating detection device of a new-energy electric automobile and comprises a high-voltage subsystem, an AD (Analog to Digital) sampling subsystem, an isolation subsystem, a communication subsystem and a fault alarming subsystem. According to the insulating detection system provided by the invention, through respectively connecting different resistors with a positive ground and a negative ground of the power battery in parallel, resistance values of insulating resistors can be calculated through collecting the voltages which are not merged into the resistors and the voltages which are merged into the resistors; the resistance values are output to a whole automobile controller through a communication module, and operation states of high-voltage circuits of the electric automobile are controlled, so that the safety of people and the electric automobile is ensured.

Description

A kind of used for electric vehicle electrokinetic cell insulation detection system and method

Technical field

The present invention relates to the battery management system in electric automobile field, a kind of specifically HVDC electrical isolation detection system and method.

Background technology

Electric automobile is the electromechanical assembly of a complicacy, and the electric automobile condition of work is more abominable, and the rapid variation of vibration, temperature and humidity all might cause the aging rapidly even damage in insulation of power cable and other insulating material, and apparatus insulated performance is descended.This not only can influence the normal control of vehicle, goes back the entail dangers to personal safety.Therefore, measure the insulating property between high-voltage electrical apparatus and the vehicle body accurately, in real time, significant to guaranteeing passenger and vehicle safety, electrical equipment operate as normal.

Existing insulation detection technique is just carried out qualitative detection to battery high-pressure system state of insulation, infers its electric leakage state, can not accurately judge the electric leakage degree; And the positive pole that the insulation detection system among this paper can accurately calculate high-pressure system is to vehicle body ground, the negative pole insulation resistance value accurately to vehicle body ground, thereby the real-time running state of electric motor car high-tension circuit is monitored, and ensured travel safety.

Summary of the invention

The object of the present invention is to provide a kind of used for electric vehicle electrokinetic cell insulation detection system and method.Through this system not only can accurate Calculation high pressure both positive and negative polarity to the insulating resistance value on vehicle body ground, can pass through communication system simultaneously, in real time insulation resistance value is monitored and fault alarm.

In order to realize the object of the invention, the used for electric vehicle electrokinetic cell insulation detection system that the present invention proposes,

A kind of used for electric vehicle electrokinetic cell insulation detection system; Be to be used to detect the Circuits System of electric automobile high-tension battery bag 10 high pressure both positive and negative polarities, comprise high pressure sub-system, AD sampled subsystem, separaant system, communication subsystem the insulation resistance value of vehicle body ground (GND).Said insulation detection system high-pressure section is made up of power brick (10), and the battery module that this power brick is made up of several cell SP is formed; This power brick two ends connect insulation testing circuit, and this insulation testing circuit comprises and is connected the anodal equivalent insulation resistance R of power brick 10 positive poles to vehicle body ground (GND) _pBe connected in parallel on this positive pole equivalence insulation resistance R _pThe anodal auxiliary resistance R at two ends _K1, and at the negative pole equivalence insulation resistance R of power brick (10) negative pole to vehicle body ground (GND) _nBe connected in parallel on this negative pole equivalence insulation resistance R _nThe negative pole auxiliary resistance R at two ends _K2, and control anodal auxiliary resistance R respectively _K1, negative pole auxiliary resistance R _K2The anodal CS K of place in circuit ₁, negative pole CS K ₂The AD sampled subsystem is measured the voltage of said power brick both positive and negative polarity and is outputed to whole-control system through said communication subsystem and separaant system.

As further characteristic of the present invention, said AD sampled subsystem comprises calculus of differences circuit and AD sample circuit.

As further characteristic of the present invention, also comprise an error alarm subsystem, it is connected with said entire car controller.

According to the object of the invention, the present invention also proposes a kind of used for electric vehicle electrokinetic cell insulation detecting method, and it is applicable to and detects the method for electric automobile high-tension battery bag (10) high pressure both positive and negative polarity to the insulation resistance value of vehicle body ground (GND), may further comprise the steps:

1) makes anodal CS K ₁, negative pole CS K ₂Be in off-state, measure anodal first voltage U of power brick (10) vehicle body ground (GND) by AD sampled subsystem (11) _PCWith first voltage U of negative pole to vehicle body ground (GND) _N0, can obtain formula [1] by circuital law

[1]

$\frac{U_{p0}}{R_p}=\frac{U_{n0}}{R_n}$

2) these two voltages are compared; If anodal first voltage U to vehicle body ground _P0=0, the said error alarm subsystem positive pressure utmost point insulation fault of offering a high price is if negative pole is to the voltage U on vehicle body ground _N0=0, said error alarm subsystem is offered a high price and is pressed the negative pole insulation fault;

3) if anodal first voltage U to vehicle body ground _P0＞=negative pole is to first voltage U on vehicle body ground _N0, closed anodal CS K ₁, break off negative pole CS K ₂, measure power brick 10 positive poles to second voltage U of vehicle body ground GND _P1With second voltage U of negative pole to vehicle body ground GND _N1, get formula [2] according to voltage divider principle,

[2]

$\frac{U_{p1}}{\frac{R_p\×R_{k1}}{R_p+R_{k1}}}=\frac{U_{n1}}{R_n}$

Calculate insulating resistance value R according to formula [1], [2] _p, R _n

4) if anodal first voltage U to vehicle body ground _P0＜negative pole is to first voltage U on vehicle body ground _N0, closed negative pole CS K ₂, break off anodal CS K ₁, measure the anodal tertiary voltage U of power brick (10) to vehicle body ground (GND) _P2With the tertiary voltage U of negative pole to vehicle body ground (GND) _N2, get formula [3] according to voltage divider principle,

[3]

$\frac{U_{p2}}{R_p}=\frac{U_{n2}}{\frac{R_n\&times;R_{k2}}{R_n+{\mathrm{<figure-callout\; id="2"\; label="R\; k"\; filenames="HDA0000099860040000012.png"\; state="\{\{state\}\}">R</figure-callout>}}_k}}$

Calculate insulating resistance value R according to formula [1], [3] _p, R _n

Owing to adopt above technical scheme; Used for electric vehicle electrokinetic cell of the present invention insulation detection system the electrokinetic cell anode over the ground, negative terminal incorporates different resistance over the ground respectively into; The voltage of incorporating the resistance front and back through collection into calculates the insulation resistance resistance; Export entire car controller to through communication module, the running status of electric automobile high-tension circuit is monitored in real time, ensure safety of person vehicle.

Description of drawings

Fig. 1 is a used for electric vehicle insulation detection system structural drawing of the present invention.

Fig. 2-1 is the circuit diagram of cathode voltage sampled subsystem of the present invention.

Fig. 2-2 is the circuit diagram of cathode voltage sampled subsystem of the present invention.

Fig. 3 does not all incorporate the equivalent schematic diagram of auxiliary resistance into for insulation testing circuit both positive and negative polarity proposed by the invention.

Fig. 4 incorporates the equivalent schematic diagram of auxiliary resistance into for insulation testing circuit positive pole proposed by the invention.

Fig. 5 incorporates the equivalent schematic diagram of auxiliary resistance into for insulation testing circuit negative pole proposed by the invention.

Embodiment

Below in conjunction with accompanying drawing and embodiment, the present invention is described further.

In following accompanying drawing, 10 is the power accumulator bag, R _pBe the equivalent over the ground insulating resistance value of power accumulator positive pole, R _nBe power accumulator negative pole equivalent resistance over the ground, R _K-1Be anodal auxiliary resistance, R _K2Be negative pole auxiliary resistance, K ₁Be anodal CS, K ₂Be negative pole CS, U _Pi, U _NiBe respectively first, second and tertiary voltage value (i=0,1,2) that positive and negative electrode resistance is divided.

Fig. 1 is the general structure block diagram of used for electric vehicle electrokinetic cell insulation detection system of the present invention, and this system mainly is made up of five sub-systems: high pressure sub-system, AD sampled subsystem 11, separaant system, communication subsystem, error alarm subsystem.Said insulation detection system high-pressure section is made up of power brick, and the battery module that this power brick is made up of several cell SP is formed; This power brick two ends connect insulation testing circuit 12, and this insulation testing circuit 12 comprises and is connected power brick 10, the positive pole anodal equivalent insulation resistance R to vehicle body ground GND _pBe connected in parallel on this positive pole equivalence insulation resistance R _pThe anodal auxiliary resistance R at two ends _K1, and at the negative pole equivalence insulation resistance R of power brick 10 negative poles to vehicle body ground GND _nBe connected in parallel on this negative pole equivalence insulation resistance R _nThe negative pole auxiliary resistance R at two ends _K2, and control anodal auxiliary resistance R respectively _K1, negative pole auxiliary resistance R _K2The anodal CS K of place in circuit ₁, negative pole CS K ₂The AD sampled subsystem is measured the voltage of said power brick both positive and negative polarity and is outputed to entire car controller MCU through communication subsystem and separaant system.Its workflow is: as shown in Figure 3, measure the first magnitude of voltage U before both positive and negative polarity is incorporated resistance into respectively through the AD sampled subsystem _P0, U _N0, MCU judges both positive and negative polarity CS K according to recording magnitude of voltage ₁, K ₂Disconnection with closed, incorporate auxiliary resistance R into through the measurement of AD sampled subsystem again _K1Or R _K2After the second magnitude of voltage U _P1, U _N1Perhaps tertiary voltage value U _P2, U _N2,, just can accurately calculate R according to twice measurement result _p, R _nValue, export MCU to, judge by MCU to be uploaded to entire car controller to insulation resistance value simultaneously and make the whether judgement of fault alarm.

Communication separaant system among Fig. 1 is used for the isolation of electric automobile high tension loop and low-voltage control circuit, has ensured the security of system, has improved antijamming capability.

Fig. 2-1 is the detailed schematic diagram of anodal AD sampled subsystem; Fig. 2-2 is the detailed schematic diagram of negative pole AD sampled subsystem; Adopted the calculus of differences circuit as input in the native system, common mode input signal has been had very strong inhibition ability, can suppress to bring the influence of circuit by the variation of external condition; Like temperature noise etc., thereby improved the degree of accuracy of AD sampling.

Through the method that used for electric vehicle electrokinetic cell insulation detection system of the present invention realizes, it is applicable to and detects the method for electric automobile high-tension battery bag 10 high pressure both positive and negative polarities to the insulation resistance value of vehicle body ground GND, comprises as follows:

1) as shown in Figure 3, make CS K ₁, K ₂All break off, first voltage of measuring between positive and negative bus and the vehicle body ground GND is respectively U _P0, U _N0, can obtain formula [1] by circuital law

[1]

$\frac{U_{p0}}{R_p}=\frac{U_{n0}}{R_n}$

2) these two voltages are compared; If anodal first voltage U to vehicle body ground _P0=0, the error alarm subsystem positive pressure utmost point insulation fault of offering a high price is if negative pole is to first voltage U on vehicle body ground _N0=0, error alarm subsystem is offered a high price and is pressed the negative pole insulation fault;

3) if anodal first voltage U to vehicle body ground _P0＞=negative pole is to first voltage U on vehicle body ground _N0, as shown in Figure 4, anodal CS K ₁Closed, negative pole control K ₂Break off, then between positive bus-bar and vehicle body ground, add standard biasing resistor R _K1, second voltage of measuring between positive and negative bus and the vehicle body ground is respectively U _P1, U _N1, can obtain formula [2] equally

[2]

$\frac{U_{p1}}{\frac{R_p\&times;R_{k1}}{R_p+R_{k1}}}=\frac{U_{n1}}{R_n}$

4) if anodal first voltage U to vehicle body ground _P0＜negative pole is to first voltage U on vehicle body ground _N0, as shown in Figure 5, anodal CS K ₁Disconnection, negative pole control K ₂Closure then adds standard biasing resistor R between negative busbar and vehicle body ground _K2, the tertiary voltage of measuring between positive and negative bus and the vehicle body ground is respectively U _P2, U _N2, can obtain formula [3] equally

[3]

$\frac{U_{p2}}{R_p}=\frac{U_{n2}}{\frac{R_n\&times;R_{k2}}{R_n+{\mathrm{<figure-callout\; id="2"\; label="R\; k"\; filenames="HDA0000099860040000012.png"\; state="\{\{state\}\}">R</figure-callout>}}_k}}$

5) judge by the MCU controller, work as U _P0More than or equal to U _N0, get formula [4] by formula [1], [2].

[4]

$\left\{\begin{array}{c}{R}_p=\frac{R_{k1}({\mathrm{<figure-callout\; id="0"\; label="U\; p"\; filenames="HDA0000099860040000031.png"\; state="\{\{state\}\}">U</figure-callout>}}_p\&times;U_{n1}-U_{p1}\&times;U_{n0})}{{\mathrm{<figure-callout\; id="0"\; label="U\; n"\; filenames="HDA0000099860040000031.png"\; state="\{\{state\}\}">U</figure-callout>}}_n\&times;U_{p1}}\\ R_n=\frac{R_{k1}({\mathrm{<figure-callout\; id="0"\; label="U\; p"\; filenames="HDA0000099860040000031.png"\; state="\{\{state\}\}">U</figure-callout>}}_p\&times;U_{n1}-U_{p1}\&times;U_{n0})}{U_{p1}\&times;{\mathrm{<figure-callout\; id="0"\; label="U\; p"\; filenames="HDA0000099860040000031.png"\; state="\{\{state\}\}">U</figure-callout>}}_p}\end{array}\right.$

6) judge by the MCU controller, work as U _P0Less than U _N0, get formula [5] by formula [1], [3].

[5]

$\left\{\begin{array}{c}{R}_p=\frac{R_{k2}({\mathrm{<figure-callout\; id="2"\; label="U\; p"\; filenames="HDA0000099860040000012.png"\; state="\{\{state\}\}">U</figure-callout>}}_p\&times;U_{n0}-{\mathrm{<figure-callout\; id="0"\; label="U\; p"\; filenames="HDA0000099860040000031.png"\; state="\{\{state\}\}">U</figure-callout>}}_p\&times;U_{n2})}{{\mathrm{<figure-callout\; id="0"\; label="U\; n"\; filenames="HDA0000099860040000031.png"\; state="\{\{state\}\}">U</figure-callout>}}_n\&times;U_{n2}}\\ R_n=\frac{R_{k2}({\mathrm{<figure-callout\; id="2"\; label="U\; p"\; filenames="HDA0000099860040000012.png"\; state="\{\{state\}\}">U</figure-callout>}}_p\&times;U_{n0}-{\mathrm{<figure-callout\; id="0"\; label="U\; p"\; filenames="HDA0000099860040000031.png"\; state="\{\{state\}\}">U</figure-callout>}}_p\&times;U_{n2})}{U_{\mathrm{<figure-callout\; id="0"\; label="p"\; filenames="HDA0000099860040000031.png"\; state="\{\{state\}\}">p</figure-callout>}0}\&times;{\mathrm{<figure-callout\; id="2"\; label="U\; n"\; filenames="HDA0000099860040000012.png"\; state="\{\{state\}\}">U</figure-callout>}}_n}\end{array}\right.$

7), just can accurately calculate power accumulator high pressure positive and negative terminal respectively to the insulation resistance value R of vehicle body ground GND according to formula [4] or formula [5] _p, R _n

According to the requirement of system, to the insulation resistance value R that calculates to insulating property _p, R _nCarry out fault distinguishing, be uploaded to entire car controller through communication subsystem simultaneously.

But above-mentioned embodiment is exemplary, is to be the restriction that this patent is comprised scope in order better to make those skilled in the art can understand this patent, can not to be interpreted as; So long as according to spirit that this patent discloses done anyly be equal to change or modify, all fall into the scope that this patent comprises.

Claims (4)

1. used for electric vehicle electrokinetic cell insulation detection system; Be to be used to detect the Circuits System of electric automobile high-tension battery bag (10) high pressure both positive and negative polarity to the insulation resistance value of vehicle body ground (GND); Comprise high pressure sub-system, AD sampled subsystem, separaant system, communication subsystem; It is characterized in that: said insulation detection system high-pressure section is made up of power brick (10), and the battery module that this power brick is made up of several cell SP is formed; This power brick two ends connect insulation testing circuit, and this insulation testing circuit comprises and is connected the anodal equivalent insulation resistance (R of power brick (10) positive pole to vehicle body ground (GND) _p) and be connected in parallel on this positive pole equivalence insulation resistance (R _p) the anodal auxiliary resistance (R at two ends _K1), and at the negative pole equivalence insulation resistance (R of power brick (10) negative pole to vehicle body ground (GND) _n) and be connected in parallel on this negative pole equivalence insulation resistance (R _n) the negative pole auxiliary resistance (R at two ends _K2), and control anodal auxiliary resistance (R respectively _K1), negative pole auxiliary resistance (R _K2) the anodal CS (K of place in circuit ₁), negative pole CS (K ₂); The AD sampled subsystem is measured the voltage of said power brick both positive and negative polarity and is outputed to entire car controller through said communication subsystem and separaant system.

2. used for electric vehicle electrokinetic cell insulation detection system according to claim 1, it is characterized in that: said AD sampled subsystem comprises calculus of differences circuit and AD sample circuit.

3. used for electric vehicle electrokinetic cell insulation detection system according to claim 1 and 2, it is characterized in that: also comprise an error alarm subsystem, it is connected with said entire car controller.

4. used for electric vehicle electrokinetic cell insulation detecting method according to claim 3 is to be used to detect the method for electric automobile high-tension battery bag (10) high pressure both positive and negative polarity to the insulation resistance value of vehicle body ground (GND), it is characterized in that: may further comprise the steps:

1) makes anodal CS (K ₁), negative pole CS (K ₂) be in off-state, measure the anodal first voltage (U of power brick (10) by AD sampled subsystem (11) to vehicle body ground (GND) _P0) and negative pole to the first voltage (U of vehicle body ground (GND) _P0), can obtain formula [1] by circuital law

[1]

$\frac{U_{p0}}{R_p}=\frac{U_{n0}}{R_n}$

2) these two voltages are compared; If the anodal first voltage (U to vehicle body ground _P0)=0, the said error alarm subsystem positive pressure utmost point insulation fault of offering a high price is if negative pole is to the first voltage (U on vehicle body ground _N0Offer a high price and press the negative pole insulation fault in)=0, said error alarm subsystem;

3) if the anodal first voltage (U to vehicle body ground _P0)＞=negative pole is to the first voltage (U on vehicle body ground _N0), closed anodal CS (K ₁), break off negative pole CS (K ₂), measure the anodal second voltage (U of power brick (10) to vehicle body ground (GND) _P1) and negative pole to the second voltage (U of vehicle body ground (GND) _N1), get formula [2] according to voltage divider principle,

[2]

$\frac{U_{p1}}{\frac{R_p\&times;R_{k1}}{R_p+R_{k1}}}=\frac{U_{n1}}{R_n}$

Calculate insulating resistance value R according to formula [1], [2] _p, R _n

4) if the anodal first voltage (U to vehicle body ground _P0)＜negative pole is to the first voltage (U on vehicle body ground _N0), closed negative pole CS (K ₂), break off anodal CS (K ₁), measure the anodal tertiary voltage (U of power brick (10) to vehicle body ground (GND) _P2) and negative pole to the tertiary voltage (U of vehicle body ground (GND) _N2), get formula [3] according to voltage divider principle,

[3]

$\frac{U_{p2}}{R_p}=\frac{U_{n2}}{\frac{R_n\&times;R_{k2}}{R_n+R_{k2}}}$

Calculate insulating resistance value R according to formula [1], [3] _p, R _n

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