CN112659898A - Fault diagnosis device and method for insulation resistance detection circuit of automobile and automobile - Google Patents

Fault diagnosis device and method for insulation resistance detection circuit of automobile and automobile Download PDF

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CN112659898A
CN112659898A CN202011389612.6A CN202011389612A CN112659898A CN 112659898 A CN112659898 A CN 112659898A CN 202011389612 A CN202011389612 A CN 202011389612A CN 112659898 A CN112659898 A CN 112659898A
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sampling
resistor
voltage
unit
insulation
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CN112659898B (en
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单成龙
李港
胡聪
宋爱
刘兆斌
宋健
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Gree Electric Appliances Inc of Zhuhai
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Gree Electric Appliances Inc of Zhuhai
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Abstract

The invention discloses a fault diagnosis device and method for an insulation resistance detection circuit of an automobile and the automobile, wherein the device comprises: the control unit controls the switches of the first sampling switch unit and the second sampling switch unit; the detection unit is used for sampling a first sampling voltage on the first sampling resistor and sampling a second sampling voltage on the second sampling resistor; the control unit is used for determining whether the first sampling resistor and/or the first voltage dividing resistor unit has a fault or not according to the first sampling voltage so as to prompt and protect under the condition of the fault; and determining whether the second sampling resistor and/or the second voltage dividing resistor unit has a fault according to the second sampling voltage, so as to prompt and protect under the condition of the fault. This scheme detects and protects through insulation resistance's short-circuit fault in to the insulation quality of whole car is promoted, reduces the potential safety hazard that causes vehicle and driver and crew.

Description

Fault diagnosis device and method for insulation resistance detection circuit of automobile and automobile
Technical Field
The invention belongs to the technical field of automobiles, and particularly relates to a fault diagnosis device and method for an insulation resistance detection circuit of an automobile and the automobile, in particular to the fault diagnosis device and method for the insulation resistance detection circuit of the automobile and the automobile.
Background
Under the background that the traditional energy resources are increasingly tense and the ecological environment protection requirements are continuously improved, the new energy automobile is rapidly developed. The prospect of the new energy automobile (such as electric automobile) industry construction in China is definitely from the automobile kingdom to the automobile republic of China. For the electric automobile, the problems of cruising ability and safety are soft ribs of the electric automobile, which seriously restrict the development of the electric automobile, especially the safety problem.
Bus voltage of a vehicle-mounted power supply system of an electric automobile is generally hundreds of volts or even kilovolts, and the safety problem of the bus voltage of the vehicle-mounted power supply system is particularly important. When the working environment of the electric automobile is severe, the rapid aging and even insulation damage of power cables and other insulation materials can be accelerated, so that the insulation strength is greatly reduced, and the personal safety of drivers and passengers is seriously endangered.
The high voltage insulation performance of the electric automobile is concerned with the equipment safety and the personnel safety. The high-reliability insulation resistance detection circuit has great significance for ensuring passenger safety, normal work of electrical equipment and safe operation of vehicles. However, when the insulation resistance in the insulation resistance detection circuit is short-circuited, the reliability of the insulation detection circuit is reduced, the insulation performance of the whole vehicle is affected, and the safety of the vehicle, the driver and the passengers is endangered.
The above is only for the purpose of assisting understanding of the technical aspects of the present invention, and does not represent an admission that the above is prior art.
Disclosure of Invention
The invention aims to provide a fault diagnosis device and method for an insulation resistance detection circuit of an automobile and the automobile, and aims to solve the problems that the insulation performance of the whole automobile is influenced when the insulation resistance of the insulation resistance detection circuit of a vehicle-mounted power supply system of the electric automobile is short-circuited, and the safety of the automobile and drivers and passengers is endangered, so that the short-circuit fault of the insulation resistance in the insulation detection circuit is detected and protected, the insulation performance of the whole automobile is improved, and the potential safety hazard to the automobile and the drivers and passengers is reduced.
The present invention provides a fault diagnosis device for an insulation resistance detection circuit of an automobile, wherein the insulation resistance detection circuit comprises: a first sampling resistor and a first divider resistor unit connected to a positive electrode of the battery pack of the automobile, and a second sampling resistor and a second divider resistor unit connected to a negative electrode of the battery pack of the automobile; the first sampling resistor is connected with the second sampling resistor; the fault diagnosis device for the insulation resistance detection circuit of the automobile comprises: the device comprises a first sampling switch unit, a second sampling switch unit, a detection unit and a control unit; the first sampling switch unit is arranged between the first sampling resistor and the first voltage dividing resistor unit; the second sampling switch unit is arranged between the second sampling resistor and the second voltage dividing resistor unit; wherein the control unit is configured to control switching of the first sampling switching unit and the second sampling switching unit; the detection unit is configured to sample a first sampling voltage on the first sampling resistor and sample a second sampling voltage on the second sampling resistor under the condition of controlling the switches of the first sampling switch unit and the second sampling switch unit; the control unit is further configured to determine whether the first sampling resistor and/or the first divider resistor unit fails according to the first sampling voltage, so as to prompt and protect in case of failure of the first sampling resistor and/or the first divider resistor unit; and determining whether the second sampling resistor and/or the second voltage dividing resistor unit has a fault according to the second sampling voltage so as to prompt and protect under the condition that the second sampling resistor and/or the second voltage dividing resistor unit has a fault.
In some embodiments, the control unit determines whether the first sampling resistor and/or the first voltage dividing resistor unit is failed according to the first sampling voltage in the same manner as that of determining whether the second sampling resistor and/or the second voltage dividing resistor unit is failed according to the second sampling voltage.
In some embodiments, the first sampling switch unit includes: a first sampling switch and a first capacitor which are arranged between the first sampling resistor and the first voltage dividing resistor unit in parallel; the second sampling switch unit includes: the second sampling switch and the second capacitor are arranged between the second sampling resistor and the second voltage dividing resistor unit in parallel; the control unit controls the switches of the first sampling switch unit and the second sampling switch unit, and includes: controlling the first sampling switch to be switched on and controlling the second sampling switch to be switched off; the detection unit, under the condition of controlling the switch of the first sampling switch unit and the second sampling switch unit, detects the first sampling voltage on the first sampling resistor, and includes: and under the condition that the first sampling switch is switched on and the second sampling switch is switched off, detecting a first sampling voltage on the first sampling resistor.
In some embodiments, the control unit determining whether the first sampling resistor and/or the first voltage dividing resistor unit is failed according to the first sampling voltage includes: if the first sampling voltage is 0, determining that the first sampling resistor has a short-circuit fault; if the first sampling voltage is not 0 and is smaller than a first calculation coefficient multiple of a first insulation voltage on a first insulation resistor, determining that the first voltage dividing resistor unit has a short-circuit fault, and determining a fault point of the first voltage dividing resistor unit; the first calculation coefficient is the ratio of the resistance value of the first sampling resistor to the sum of the resistance values of the first divider resistor unit; and if the first sampling voltage is not 0 and is equal to a first calculation coefficient multiple of the first insulation voltage on the first insulation resistor, determining that the insulation resistor detection circuit is normal.
In some embodiments, further comprising: a first voltage division switch unit; the first voltage dividing resistance unit includes: the first voltage dividing resistor to the nth voltage dividing resistor are connected in series; the first voltage division switching unit includes: first to nth voltage dividing switches; each voltage division switch is connected in parallel with two ends of a corresponding voltage division resistor; n is a positive integer; the control unit, which determines the failure point of the first voltage dividing resistance unit, includes: if the first sampling voltage is a second calculation coefficient multiple of the first insulation voltage on the first insulation resistor, and the value of the first sampling voltage is kept unchanged after m voltage division switches from the first voltage division switch to the nth voltage division switch are closed, determining that m voltage division resistors connected with the m voltage division switches in parallel have short-circuit faults; the second calculation coefficient is the ratio of the resistance of the first sampling resistor to the sum of the resistances of the remaining divider resistors, and m is greater than or equal to 1 and less than or equal to n.
In accordance with the above apparatus, a further aspect of the present invention provides an automobile comprising: the above-described fault diagnosis device for an insulation resistance detection circuit of an automobile.
In a further aspect of the present invention, matched to the above vehicle, there is provided a fault diagnosis method for an insulation resistance detection circuit of a vehicle, where the insulation resistance detection circuit includes: a first sampling resistor and a first divider resistor unit connected to a positive electrode of the battery pack of the automobile, and a second sampling resistor and a second divider resistor unit connected to a negative electrode of the battery pack of the automobile; the first sampling resistor is connected with the second sampling resistor; the fault diagnosis method of the insulation resistance detection circuit of the automobile comprises the following steps: the control unit controls the switches of the first sampling switch unit and the second sampling switch unit; through a detection unit, under the condition of controlling the switches of the first sampling switch unit and the second sampling switch unit, sampling a first sampling voltage on the first sampling resistor, and sampling a second sampling voltage on the second sampling resistor; determining whether the first sampling resistor and/or the first divider resistor unit has a fault or not according to the first sampling voltage through a control unit, so as to prompt and protect under the condition that the first sampling resistor and/or the first divider resistor unit has a fault; and determining whether the second sampling resistor and/or the second voltage dividing resistor unit has a fault according to the second sampling voltage so as to prompt and protect under the condition that the second sampling resistor and/or the second voltage dividing resistor unit has a fault.
In some embodiments, determining, by the control unit, whether the first sampling resistor and/or the first voltage dividing resistor unit is failed according to the first sampling voltage is the same as determining whether the second sampling resistor and/or the second voltage dividing resistor unit is failed according to the second sampling voltage.
In some embodiments, the first sampling switch unit includes: a first sampling switch and a first capacitor which are arranged between the first sampling resistor and the first voltage dividing resistor unit in parallel; the second sampling switch unit includes: the second sampling switch and the second capacitor are arranged between the second sampling resistor and the second voltage dividing resistor unit in parallel; through the control unit, control the switch of first sampling switch unit and second sampling switch unit, include: controlling the first sampling switch to be switched on and controlling the second sampling switch to be switched off; detecting, by a detection unit, a first sampling voltage across the first sampling resistor under a condition that switches of the first sampling switch unit and the second sampling switch unit are controlled, including: and under the condition that the first sampling switch is switched on and the second sampling switch is switched off, detecting a first sampling voltage on the first sampling resistor.
In some embodiments, determining, by the control unit, whether the first sampling resistor and/or the first voltage dividing resistor unit is faulty according to the first sampling voltage includes: if the first sampling voltage is 0, determining that the first sampling resistor has a short-circuit fault; if the first sampling voltage is not 0 and is smaller than a first calculation coefficient multiple of a first insulation voltage on a first insulation resistor, determining that the first voltage dividing resistor unit has a short-circuit fault, and determining a fault point of the first voltage dividing resistor unit; the first calculation coefficient is the ratio of the resistance value of the first sampling resistor to the sum of the resistance values of the first divider resistor unit; and if the first sampling voltage is not 0 and is equal to a first calculation coefficient multiple of the first insulation voltage on the first insulation resistor, determining that the insulation resistor detection circuit is normal.
In some embodiments, further comprising: determining, by a control unit, a failure point of the first voltage dividing resistance unit, including: if the first sampling voltage is a second calculation coefficient multiple of the first insulation voltage on the first insulation resistor, and the value of the first sampling voltage is kept unchanged after m voltage division switches from the first voltage division switch to the nth voltage division switch are closed, determining that m voltage division resistors connected with the m voltage division switches in parallel have short-circuit faults; the second calculation coefficient is the ratio of the resistance of the first sampling resistor to the sum of the resistances of the remaining divider resistors, and m is greater than or equal to 1 and less than or equal to n.
Therefore, according to the scheme of the invention, whether the insulation resistor is short-circuited can be determined by detecting the voltage on the insulation resistor; the detection switch is arranged at the insulation resistor in the insulation detection circuit, so that the fault position of the insulation resistor can be positioned, and the short-circuit fault of the insulation resistor in the insulation detection circuit is detected and protected, so that the insulation performance of the whole vehicle is improved, and the potential safety hazard caused to vehicles, drivers and passengers is reduced.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.
Drawings
Fig. 1 is a schematic structural diagram of an embodiment of a fault diagnosis apparatus for an insulation resistance detection circuit of an automobile according to the present invention;
FIG. 2 is a schematic diagram of an embodiment of an insulation resistance detection circuit;
FIG. 3 is a schematic diagram of an embodiment of a fault detection circuit;
fig. 4 is a flowchart illustrating a method for diagnosing a fault in an insulation resistance detection circuit of an automobile according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the specific embodiments of the present invention and the accompanying drawings. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. 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.
According to an embodiment of the present invention, there is provided a fault diagnosis device of an insulation resistance detection circuit of an automobile. Referring to fig. 1, a schematic diagram of an embodiment of the apparatus of the present invention is shown. The insulation resistance detection circuit includes: the battery pack voltage measuring device comprises a first sampling resistor and first voltage dividing resistor unit connected to the positive pole of the battery pack of the automobile, and a second sampling resistor and second voltage dividing resistor unit connected to the negative pole of the battery pack of the automobile. The first sampling resistor is connected with the second sampling resistor, a first insulation resistor of the positive pole of the battery pack to the casing ground is connected to the first voltage dividing resistor unit, and a second insulation resistor of the negative pole of the battery pack to the casing ground is connected to the second voltage dividing resistor unit. Wherein the battery pack of the automobile consists of a battery B1To battery BnThe positive pole of the battery pack is a bus positive BAT + and the negative pole of the battery pack is a bus negative BAT-. A first insulation resistor having a resistance value of RpA second insulation resistance such as a resistance value of RnThe insulation resistance of (1). A first sampling resistor, e.g. Rs1A first voltage dividing resistor unit such as a voltage dividing resistor Rp1、....、RpnA second sampling resistor such as Rs2A second voltage dividing resistor unit such as a voltage dividing resistor Rn1、....、Rnn。
The fault diagnosis device for the insulation resistance detection circuit of the automobile comprises: the device comprises a first sampling switch unit, a second sampling switch unit, a detection unit and a control unit. The first sampling switch unit is arranged between the first sampling resistor and the first voltage dividing resistor unit. The second sampling switch unit is arranged between the second sampling resistor and the second voltage dividing resistor unit.
Wherein the control unit is configured to control switching of the first sampling switching unit and the second sampling switching unit. Wherein, the on is opened, and the off is closed.
The detection unit is configured to sample a first sampling voltage on the first sampling resistor and sample a second sampling voltage on the second sampling resistor under the condition of controlling the switches of the first sampling switch unit and the second sampling switch unit.
Of course, in the case of determining the resistance values of the first and second insulation resistors, the detection unit further needs to sample the voltages at the first and second voltage dividing resistor units. That is, the detection unit is configured to sample a first sampling voltage across the first sampling resistor and sample a first divided voltage sequence such as a voltage U across the first divided resistor unit while controlling the switching of the first sampling switch unit and the second sampling switch unitp1、....、Upn. Sampling a second sampling voltage on the second sampling resistor, and sampling a second voltage division voltage sequence such as U on the second voltage division resistor unitn1、....、Unn。
Wherein, the sampling resistor R is detecteds1Voltage U ons1Is used for detecting whether insulation of BAT + path to ground is abnormal or not, and detecting sampling resistor Rs2Voltage U ons2The detection method is used for detecting whether the insulation resistance between the BAT-end and the ground is abnormal, the working principle of the two branches is the same, and the detection ranges are different.
The control unit is further configured to determine a first insulation resistance of the positive pole of the battery pack to the chassis ground and a second insulation resistance of the negative pole of the battery pack to the chassis ground according to the first sampling voltage. Or, according to the second sampling voltage, determining a first insulation resistance of the positive pole of the battery pack to the chassis ground and a second insulation resistance of the negative pole of the battery pack to the chassis ground.
And the control unit, such as an MCU, determines the mode of a first insulation resistance of the positive pole of the battery pack to the chassis ground and a second insulation resistance of the negative pole of the battery pack to the chassis ground according to the first sampling voltage. The first insulation resistance of the positive pole of the battery pack to the chassis ground and the second insulation resistance of the negative pole of the battery pack to the chassis ground are determined according to the second sampling voltage.
A specific manner in which the control unit determines the first insulation resistance of the positive pole of the battery pack to the chassis ground and the second insulation resistance of the negative pole of the battery pack to the chassis ground according to the first sampling voltage will be described below.
See the example shown in FIG. 2, Rp、RnInsulation resistance values, R, of the bus positive BAT + and the bus negative BAT-to the chassis ground, respectivelys1、Rs2For sampling resistors, Rp1、....、Rpn、 and Rn1、....、RnnIs a voltage dividing resistor. Operational amplifier A1And a resistance R1、R2An in-phase proportional amplifying circuit is formed. Operational amplifier A2And a resistance R3、R4Form an inverse proportion amplifying circuit because of the sampling resistor Rs2The voltage on the MCU is negative voltage, so the MCU can read the voltage by changing the voltage into positive voltage through the inverter. Ks1、Ks2For switching devices, by closing switch K alones1 and Ks2Can calculate the insulation resistance value Rp and Rn. The method comprises the following specific steps:
first of all, the switch K is closeds1And a disconnecting switch Ks2Detecting the sampling resistance Rs1Voltage U ons1Passing voltage Us1The divider resistance R can be calculatedp1Voltage U onp1And a voltage dividing resistor Rn1Voltage U onn1：
Figure BDA0002810844470000071
Un1＝Ubus-Up1 (2)；
Figure BDA0002810844470000072
Then the switch K is closeds2Opening switch Ks1Detecting the divider resistance Rn1Voltage U onn1Passing voltage Un1The divider resistance R can be calculatedp2Voltage U onp2And a voltage dividing resistor Rn2Voltage U onn2：
Figure BDA0002810844470000073
Up2＝Ubus-Un2 (5)；
Figure BDA0002810844470000074
The insulation resistance R can be calculated by combining the formula (3) and the formula (6)p and Rn：
Figure BDA0002810844470000075
The control unit is further configured to determine whether the first sampling resistor and/or the first voltage dividing resistor unit fails according to the first sampling voltage, so as to prompt and protect the first sampling resistor and/or the first voltage dividing resistor unit from failing in the case that the first sampling resistor and/or the first voltage dividing resistor unit fails.
And determining whether the second sampling resistor and/or the second voltage dividing resistor unit has a fault according to the second sampling voltage, so as to prompt and protect the fault condition of the second sampling resistor and/or the second voltage dividing resistor unit under the condition that the second sampling resistor and/or the second voltage dividing resistor unit has a fault.
Therefore, the on-off of the switch on the corresponding sampling resistor is controlled by the control logic by calculating the sampling voltage on the corresponding sampling resistor, so that the problem of fault location of the insulation detection circuit is solved, and a fault point is located quickly and accurately; whether the insulation detection circuit is abnormal or not can be accurately detected; the number of the short-circuit resistors can be identified, and the fault position can be quickly positioned; according to the difference of the number of the short-circuit resistors, the VCU of the vehicle controller performs different protections, so that the troubleshooting time is reduced to the maximum extent, and the reliability of the vehicle is improved; when the short circuit occurs to the insulation resistor, the abnormal insulation resistor can be positioned in time, the insulation resistor can be accurately positioned, different protections can be made according to the number of the short circuit resistor, the insulation performance of the whole vehicle is greatly improved, and the safety of the vehicle, a driver and passengers is ensured.
In some embodiments, the first sampling switch unit includes: and the first sampling switch and the first capacitor are arranged between the first sampling resistor and the first voltage dividing resistor unit in parallel. The second sampling switch unit includes: and the second sampling switch and the second capacitor are arranged between the second sampling resistor and the second voltage dividing resistor unit in parallel.
The control unit controls the switches of the first sampling switch unit and the second sampling switch unit, and includes: and controlling the first sampling switch to be switched on and controlling the second sampling switch to be switched off. Specifically, take bus positive BAT + loop as an example, close switch Ks1And a disconnecting switch Ks2。
The detection unit, under the condition of controlling the switch of the first sampling switch unit and the second sampling switch unit, detects the first sampling voltage on the first sampling resistor, and includes: and under the condition that the first sampling switch is switched on and the second sampling switch is switched off, detecting a first sampling voltage on the first sampling resistor. In particular, the switch K is closeds1And a disconnecting switch Ks2Detecting the sampling resistance Rs1Voltage U ons1。
Thereby, by first pass determinationSampling resistor Rs1Upper sampled voltage Us1And different control logics are executed according to the judgment result, so that the problems that the insulation detection fault cannot be identified and the fault point can not be accurately positioned are solved, and the fault can be quickly identified and the fault point can be accurately positioned.
In some embodiments, the control unit determines whether the first sampling resistor and/or the first voltage dividing resistor unit is failed according to the first sampling voltage in the same manner as that of determining whether the second sampling resistor and/or the second voltage dividing resistor unit is failed according to the second sampling voltage.
In some embodiments, the control unit, determining whether the first sampling resistor and/or the first divider resistor unit is faulty according to the first sampling voltage, includes determining whether:
the first determination case: the control unit is specifically further configured to determine that a short-circuit fault occurs in the first sampling resistor if the first sampling voltage is 0.
Specifically, take bus positive BAT + loop as an example, close switch Ks1And a disconnecting switch Ks2Detecting the sampling resistance Rs1Voltage U ons1If voltage Us1If 0, the sampling resistance R is describeds1And (4) short-circuiting.
Second determination case: the control unit is specifically configured to determine that the first voltage dividing resistor unit has a short-circuit fault and determine a fault point of the first voltage dividing resistor unit if the first sampling voltage is not 0 and is smaller than a first calculation coefficient multiple of a first insulation voltage on a first insulation resistor. The first calculation coefficient is a ratio of the resistance of the first sampling resistor to the sum of the resistance of the first sampling resistor and the resistance of the first divider resistor unit.
Specifically, take bus positive BAT + loop as an example, close switch Ks1And a disconnecting switch Ks2Detecting the sampling resistance Rs1Voltage U ons1If voltage Us1Not equal to 0, and
Figure BDA0002810844470000091
then the voltage dividing resistor R is indicatedp1....RpnOne or more of which are short circuited.
The third determination scenario: the control unit is specifically configured to determine that the insulation resistance detection circuit is normal, that is, determine that the insulation resistance detection circuit has not failed, if the first sampling voltage is not 0 and is equal to a first calculation coefficient multiple of a first insulation voltage across a first insulation resistor.
Specifically, take bus positive BAT + loop as an example, close switch Ks1And a disconnecting switch Ks2Detecting the sampling resistance Rs1Voltage U ons1If voltage Us1Not equal to 0, and
Figure BDA0002810844470000092
the insulation detection circuit is normal.
Therefore, only the sampling resistor R needs to be detecteds1Voltage U ons1Whether the insulation detection circuit is in fault can be identified according to the sampling voltage Us1Different control logic is executed, and the fault position can be located. Therefore, whether the insulation resistance detection circuit is abnormal or not can be judged, and the insulation performance of the whole vehicle is ensured; the position and the number of the short-circuit resistors can be accurately detected, different protections are carried out according to the number of the short-circuit resistors, and meanwhile, faults can be conveniently and quickly identified for maintenance; the control mode is simple, the response speed is high, and the cost is low.
In some embodiments, further comprising: and the first voltage division switch unit is arranged corresponding to the first voltage division resistor unit. The first voltage dividing resistance unit includes: the first voltage dividing resistor to the nth voltage dividing resistor are arranged in series. The first voltage division switching unit includes: first to nth voltage dividing switches. Each voltage division switch is connected in parallel with two ends of a corresponding voltage division resistor. n is a positive integer.
Of course, the second voltage dividing resistor unit R can be includedn1、....、RnnCorrespondingly arranged second voltage-dividing switch units, e.g. Kn1、....、Knn。
Referring to the example shown in FIG. 2, at the voltage dividing resistor Rp1、....、Rpn、 and Rn1、....、RnnIn parallel with a switch on each voltage dividing resistor, i.e. in voltage dividing resistor Rp1、....、RpnUpper parallel switch Kp1、....、KpnAt the voltage dividing resistor Rn1、....、RnnUpper parallel switch Kn1、....、KnnAnd the method is used for positioning the fault position.
The control unit, which determines the failure point of the first voltage dividing resistance unit, includes: if the first sampling voltage is a second calculation coefficient multiple of the first insulation voltage on the first insulation resistor, and the value of the first sampling voltage is kept unchanged after m voltage division switches from the first voltage division switch to the nth voltage division switch are closed, determining that m voltage division resistors connected in parallel with the m voltage division switches are short-circuited, namely determining that the fault point of the first voltage division resistor unit is the fault that m voltage division resistors connected in parallel with the m voltage division switches are short-circuited. The second calculation coefficient is the ratio of the resistance of the first sampling resistor to the sum of the resistances of the remaining divider resistors, and m is greater than or equal to 1 and less than or equal to n. The rest voltage-dividing resistors are the rest voltage-dividing resistors except the m voltage-dividing resistors in the n voltage-dividing resistors.
For example: if the first sampling voltage is a first calculation coefficient multiple of the first insulation voltage on the first insulation resistor, and the value of the first sampling voltage is kept unchanged after the first voltage division switch is closed, determining that the first voltage division resistor has a short-circuit fault, namely determining that a fault point of the first voltage division resistor unit is a fault that the first voltage division resistor has a short-circuit; the first calculation coefficient is a ratio of the resistance value of the first sampling resistor to the sum of the resistance values of the second to nth divider resistors.
In particular, suppose Rp1Short circuit at this time
Figure BDA0002810844470000101
Closing switch Kp1Voltage Us1Remain unchanged.
Let R bep1Short circuit at this time
Figure BDA0002810844470000102
Closing switch Kp1Voltage Us1Remain unchanged.
Let R bepnShort circuit at this time
Figure BDA0002810844470000103
Closing switch KpnVoltage Us1Remain unchanged.
Suppose a voltage dividing resistor Rp1 and Rp2At the same time short-circuited, at this time
Figure BDA0002810844470000111
Simultaneous closing of switches Kp1And switch Kp2Voltage Us1Remain unchanged.
Suppose a voltage dividing resistor Rp1、Rp2 and Rp3At the same time short-circuited, at this time
Figure BDA0002810844470000112
Simultaneous closing of switches Kp1、Kp2 and Kp3Voltage Us1Remain unchanged.
Therefore, the situation that the short circuit of the resistors occurs can be detected simultaneously under the condition that the short circuit fault of the voltage division resistor unit is determined, the fault position is accurately positioned, and the reliability of the insulation detection circuit is improved.
Through a large number of tests, the technical scheme of the invention can determine whether the insulation resistor is short-circuited by detecting the voltage on the insulation resistor; the detection switch is arranged at the insulation resistor in the insulation detection circuit, so that the fault position of the insulation resistor can be positioned, and the short-circuit fault of the insulation resistor in the insulation detection circuit is detected and protected, so that the insulation performance of the whole vehicle is improved, and the potential safety hazard caused to vehicles, drivers and passengers is reduced.
According to an embodiment of the present invention, there is also provided an automobile corresponding to the failure diagnosis apparatus of the insulation resistance detection circuit of the automobile. The automobile may include: the above-described fault diagnosis device for an insulation resistance detection circuit of an automobile.
Because the vehicle is often in severe environments such as strong vibration, high temperature, high humidity and the like in the driving process, the insulation resistance in the insulation resistance detection circuit is easy to have faults such as short circuit, aging, poor precision and the like, the current in the insulation resistance detection circuit is increased due to the edge resistance short circuit, loss is increased due to the fact that other normal detection resistances are too large, aging of the insulation resistance is accelerated, and therefore vicious circle is formed.
When the insulation resistance is in short circuit, the insulation resistance can be accurately positioned, different protections can be made according to the number of the faults of the short circuit resistance, the insulation performance of the whole vehicle is greatly improved, and the safety of the vehicle, a driver and passengers is ensured.
For example: referring to the example shown in fig. 2, taking the BAT + path as an example, any one or more of the Rp1 to Rpn may be shorted, similarly to the insulation resistance in the BAT-path.
In some embodiments, aspects of the present invention provide an insulation resistance detection fault self-diagnosis scheme for a vehicle, which can accurately detect whether an insulation detection circuit is abnormal; the number of the short-circuit resistors can be identified, and the fault position can be quickly positioned; according to the difference of the number of the short-circuit resistors, the VCU of the whole vehicle controller performs different protections, the troubleshooting time is reduced to the maximum extent, and the reliability of the whole vehicle is improved.
For example: only one insulation resistor is in short circuit, and at the moment, the VCU can send out an insulation detection abnormal alarm signal to remind a driver; if the two insulation resistors are short-circuited, the insulativity of the whole vehicle cannot be accurately detected at the moment, the power supply of the whole vehicle is cut off, and the vehicle cannot be forced to run.
Specifically, according to the scheme of the invention, a method of combining software calculation and control logic is adopted, the sampling voltage on the corresponding sampling resistor is calculated through software, the on-off of a switch on the corresponding sampling resistor is controlled through the control logic, and the problem of fault location of the insulation detection circuit is solved, so that the effect of quickly and accurately locating a fault point is achieved.
The following describes an exemplary implementation process of the scheme of the present invention with reference to the examples shown in fig. 2 and fig. 3.
High insulation is an important prerequisite for ensuring the safety of vehicles and drivers and passengers, and a high-reliability insulation resistance detection circuit is of great importance. The short circuit of the detection resistor of the insulation resistance detection circuit causes the increase of the current of the detection loop, the loss of the normal detection resistor is increased, the damage of the acceleration resistor is accelerated, and finally the insulation detection circuit loses the detection function.
Fig. 2 is a schematic structural diagram of an embodiment of the insulation resistance detection circuit. In the example shown in FIG. 2, the battery B1To battery BnThe positive pole of the battery pack is a bus positive BAT +, the negative pole of the battery pack is a bus negative BAT-, and n is a positive integer. Rp、RnInsulation resistance values, R, of the bus positive BAT + and the bus negative BAT-to the chassis ground, respectivelys1、Rs2For sampling resistors, Rp1、....、Rpn、 and Rn1、....、RnnIs a voltage dividing resistor; operational amplifier A1And a resistance R1、R2Forming an in-phase proportional amplifying circuit; operational amplifier A2And a resistance R3、R4Form an inverse proportion amplifying circuit because of the sampling resistor Rs2The voltage on the MCU is negative voltage, so the MCU can read the voltage by changing the voltage into positive voltage through the inverter; ks1、Ks2For switching devices, by closing switch K alones1 and Ks2Can calculate the insulation resistance value Rp and Rn。
The in-phase proportional amplifying circuit and the reverse-phase proportional amplifying circuit may amplify the signals according to a predetermined scale factor. And comparing the output signal detected by the MCU with a detection signal when the insulation resistance is normal, and indicating that the insulation is abnormal when the voltage value of the output signal is not equal to that of the normal detection signal. Rp and RnRespectively representing the insulation resistance values of the positive terminal and the negative terminal of the battery to the chassis ground. The insulation resistance is a virtual existence, and the positive end and the negative end of the battery can be indirectly calculated to the ground of the shell through a bridge detection methodThe insulation resistance value can be calculated by combining the formula (3) and the formula (6). The sampling resistor and the voltage dividing resistor do not belong to insulation resistors, and are only used for detecting the insulation resistors.
In the example shown in fig. 2, the voltage dividing resistor R is providedp1、....、Rpn、 and Rn1、....、RnnIn parallel with a switch on each voltage dividing resistor, i.e. in voltage dividing resistor Rp1、....、RpnUpper parallel switch Kp1、....、KpnAt the voltage dividing resistor Rn1、....、RnnUpper parallel switch Kn1、....、KnnAnd the method is used for positioning the fault position.
In the example shown in fig. 2, the switch connected in parallel across the capacitor is inherent in the bridge detection method, and the insulation resistance value is calculated by turning on and off the switch. The switches on the sampling resistors are added.
The detection flow of the insulation resistance detection circuit of the example shown in fig. 2 may include:
step 11, first close switch Ks1And a disconnecting switch Ks2Detecting the sampling resistance Rs1Voltage U ons1Passing voltage Us1The divider resistance R can be calculatedp1Voltage U onp1And a voltage dividing resistor Rn1Voltage U onn1：
Figure BDA0002810844470000131
Un1＝Ubus-Up1 (2)；
Figure BDA0002810844470000132
wherein ,UbusAnd represents the total voltage of the battery.
Step 12, then closing switch Ks2Opening switch Ks1Detecting the divider resistance Rn1Voltage U onn1Passing voltage Un1Can calculate the scoreVoltage resistance Rp2Voltage U onp2And a voltage dividing resistor Rn2Voltage U onn2：
Figure BDA0002810844470000133
Up2＝Ubus-Un2 (5)；
Figure BDA0002810844470000134
The insulation resistance R can be calculated by combining the formula (3) and the formula (6)p and Rn：
Figure BDA0002810844470000135
Wherein, the voltage Up1Represents the voltage of the battery positive BAT + (namely the bus positive BAT +) to the ground of the vehicle body, and the voltage Un1Representing the voltage of the battery negative BAT (i.e., the bus negative BAT-), to the body ground. U shapepnRepresents the voltage of the positive terminal of the battery to the chassis ground; u shapennRepresents the voltage of the negative terminal of the battery to the chassis ground; u shapepn and UnnThe added voltage value is Ubus。
Fig. 3 is a schematic structural diagram of an embodiment of a fault detection circuit. As shown in FIG. 3, taking bus positive BAT + loop as an example, switch K is closeds1And a disconnecting switch Ks2The fault self-diagnosis flow is explained as follows:
step 21, if the voltage U iss1If 0, the sampling resistance R is describeds1And (4) short-circuiting.
Step 22, if the voltage U is applieds1Not equal to 0, and
Figure BDA0002810844470000141
then the voltage dividing resistor R is indicatedp1....RpnOne or more of which are short circuited.
Let R bep1Short circuit at this time
Figure BDA0002810844470000142
Closing switch Kp1Voltage Us1Remain unchanged.
Let R bepnShort circuit at this time
Figure BDA0002810844470000143
Closing switch KpnVoltage Us1Remain unchanged.
Suppose a voltage dividing resistor Rp1 and Rp2At the same time short-circuited, at this time
Figure BDA0002810844470000144
Simultaneous closing of switches Kp1And switch Kp2Voltage Us1Remain unchanged.
Suppose a voltage dividing resistor Rp1、Rp2 and Rp3At the same time short-circuited, at this time
Figure BDA0002810844470000145
Simultaneous closing of switches Kp1、Kp2 and Kp3Voltage Us1Remain unchanged.
Step 23, if the voltage U is applieds1Not equal to 0, and
Figure BDA0002810844470000146
the insulation detection circuit is normal. According to voltage Us1Can only judge whether the BAT + branch insulation detection circuit is normal or not and judge that the BAT-terminal needs to detect the voltage Us2。
In the example shown in steps S21 to S23, the occurrence of short circuit of a plurality of resistors can be detected simultaneously, and the fault position can be accurately located, thereby improving the reliability of the insulation detection circuit.
Thus, only the sampling resistor R needs to be detecteds1Voltage U ons1Whether the insulation detection circuit is in fault can be identified according to the sampling voltage Us1Different control logic is executed, and the fault position can be located. Therefore, whether the insulation resistance detection circuit is abnormal or not can be judged, and the insulation performance of the whole vehicle is ensured; can accurately detect short circuitThe positions and the number of the resistors are protected differently according to the number of the short-circuit resistors, and meanwhile, faults are conveniently and quickly identified for maintenance; the control mode is simple, the response speed is high, and the cost is low.
Of course, taking the bus negative BAT-as an example for calculation, the judgment specification is the same, and the method is the same in nature.
Therefore, according to the scheme of the invention, the sampling resistor R is judged firstlys1Upper sampled voltage Us1And different control logics are executed according to the judgment result, so that the problems that the insulation detection fault cannot be identified and the fault point can not be accurately positioned are solved, and the fault can be quickly identified and the fault point can be accurately positioned.
Since the processing and functions of the automobile of this embodiment are basically corresponding to the embodiment, principle and example of the device shown in fig. 1, the description of this embodiment is not given in detail, and reference may be made to the related description in the foregoing embodiment, which is not described herein again.
Through a large number of tests, the technical scheme of the invention can determine whether the insulation resistor is short-circuited by detecting the voltage on the insulation resistor; the detection switch is arranged at the position of the insulation resistor in the insulation detection circuit, so that the fault position of the insulation resistor can be positioned, the problems that the insulation detection fault cannot be identified and the fault point can be accurately positioned are solved, and the fault can be quickly identified and the fault point can be accurately positioned.
According to an embodiment of the present invention, there is also provided a fault diagnosis method for an insulation resistance detection circuit of an automobile corresponding to the automobile, as shown in fig. 4, which is a schematic flow chart of an embodiment of the method of the present invention.
The insulation resistance detection circuit includes: the battery pack voltage measuring device comprises a first sampling resistor and first voltage dividing resistor unit connected to the positive pole of the battery pack of the automobile, and a second sampling resistor and second voltage dividing resistor unit connected to the negative pole of the battery pack of the automobile. The first sampling resistor is connected with the second sampling resistor, a first insulation resistor of the positive pole of the battery pack to the casing ground is connected to the first voltage dividing resistor unit, and a second insulation resistor of the negative pole of the battery pack to the casing ground is connectedTo the second voltage-dividing resistance unit. Wherein the battery pack of the automobile consists of a battery B1To battery BnThe positive pole of the battery pack is a bus positive BAT + and the negative pole of the battery pack is a bus negative BAT-. A first insulation resistor having a resistance value of RpA second insulation resistance such as a resistance value of RnThe insulation resistance of (1). A first sampling resistor, e.g. Rs1A first voltage dividing resistor unit such as a voltage dividing resistor Rp1、....、RpnA second sampling resistor such as Rs2A second voltage dividing resistor unit such as a voltage dividing resistor Rn1、....、Rnn。
The fault diagnosis method of the insulation resistance detection circuit of the automobile comprises the following steps: step S110 to step S140.
At step S110, the switches of the first sampling switch unit and the second sampling switch unit are controlled by the control unit. Wherein, the on is opened, and the off is closed.
At step S120, a detection unit samples a first sampling voltage on the first sampling resistor and a second sampling voltage on the second sampling resistor under the condition of controlling the switches of the first sampling switch unit and the second sampling switch unit.
The first sampling switch unit is arranged between the first sampling resistor and the first voltage dividing resistor unit. And the second sampling switch unit is arranged between the second sampling resistor and the second voltage dividing resistor unit.
Of course, in the case of determining the resistance values of the first and second insulation resistors, the detection unit further needs to sample the voltages at the first and second voltage dividing resistor units. That is, the detection unit is configured to sample a first sampling voltage across the first sampling resistor and sample a first divided voltage sequence such as a voltage U across the first divided resistor unit while controlling the switching of the first sampling switch unit and the second sampling switch unitp1、....、Upn(ii) a Sampling a second sampling voltage on the second sampling resistor, and sampling the second voltage dividing resistorSecond partial voltage sequences on the element, e.g. Un1、....、Unn。
Wherein, the sampling resistor R is detecteds1Voltage U ons1Is used for detecting whether insulation of BAT + path to ground is abnormal or not, and detecting sampling resistor Rs2Voltage U ons2The detection method is used for detecting whether the insulation resistance between the BAT-end and the ground is abnormal, the working principle of the two branches is the same, and the detection ranges are different.
Determining, by a control unit, a first insulation resistance of the positive pole of the battery pack to a chassis ground and a second insulation resistance of the negative pole of the battery pack to the chassis ground according to the first sampling voltage; or, according to the second sampling voltage, determining a first insulation resistance of the positive pole of the battery pack to the chassis ground and a second insulation resistance of the negative pole of the battery pack to the chassis ground;
the control unit, such as an MCU, determines the mode of a first insulation resistance of the positive pole of the battery pack to the chassis ground and a second insulation resistance of the negative pole of the battery pack to the chassis ground according to the first sampling voltage; the first insulation resistance of the positive pole of the battery pack to the chassis ground and the second insulation resistance of the negative pole of the battery pack to the chassis ground are determined according to the second sampling voltage.
A specific manner in which the control unit determines the first insulation resistance of the positive pole of the battery pack to the chassis ground and the second insulation resistance of the negative pole of the battery pack to the chassis ground according to the first sampling voltage will be described below.
See the example shown in FIG. 2, Rp、RnInsulation resistance values, R, of the bus positive BAT + and the bus negative BAT-to the chassis ground, respectivelys1、Rs2For sampling resistors, Rp1、....、Rpn、 and Rn1、....、RnnIs a voltage dividing resistor; operational amplifier A1And a resistance R1、R2Forming an in-phase proportional amplifying circuit; operational amplifier A2And a resistance R3、R4Form an inverse proportion amplifying circuit because of the sampling resistor Rs2The upper voltage is a negative voltage, so it is necessaryThe MCU can read the voltage value changed into positive voltage through the inverter; ks1、Ks2For switching devices, by closing switch K alones1 and Ks2Can calculate the insulation resistance value Rp and Rn. The method comprises the following specific steps:
first of all, the switch K is closeds1And a disconnecting switch Ks2Detecting the sampling resistance Rs1Voltage U ons1Passing voltage Us1The divider resistance R can be calculatedp1Voltage U onp1And a voltage dividing resistor Rn1Voltage U onn1：
Figure BDA0002810844470000161
Un1＝Ubus-Up1 (2)；
Figure BDA0002810844470000171
Then the switch K is closeds2Opening switch Ks1Detecting the divider resistance Rn1Voltage U onn1Passing voltage Un1The divider resistance R can be calculatedp2Voltage U onp2And a voltage dividing resistor Rn2Voltage U onn2：
Figure BDA0002810844470000172
Up2＝Ubus-Un2 (5)；
Figure BDA0002810844470000173
The insulation resistance R can be calculated by combining the formula (3) and the formula (6)p and Rn：
Figure BDA0002810844470000174
At step S130, determining, by a control unit, whether the first sampling resistor and/or the first voltage dividing resistor unit fails according to the first sampling voltage, so as to prompt and protect the first sampling resistor and/or the first voltage dividing resistor unit from failing in case that the first sampling resistor and/or the first voltage dividing resistor unit fails.
At step S140, determining, by a control unit, whether the second sampling resistor and/or the second voltage-dividing resistor unit has a fault according to the second sampling voltage, so as to prompt and protect the second sampling resistor and/or the second voltage-dividing resistor unit from the fault in case that the second sampling resistor and/or the second voltage-dividing resistor unit has a fault.
Therefore, the on-off of the switch on the corresponding sampling resistor is controlled by the control logic by calculating the sampling voltage on the corresponding sampling resistor, so that the problem of fault location of the insulation detection circuit is solved, and a fault point is located quickly and accurately; whether the insulation detection circuit is abnormal or not can be accurately detected; the number of the short-circuit resistors can be identified, and the fault position can be quickly positioned; according to the difference of the number of the short-circuit resistors, the VCU of the vehicle controller performs different protections, so that the troubleshooting time is reduced to the maximum extent, and the reliability of the vehicle is improved; when the short circuit occurs to the insulation resistor, the abnormal insulation resistor can be positioned in time, the insulation resistor can be accurately positioned, different protections can be made according to the number of the short circuit resistor, the insulation performance of the whole vehicle is greatly improved, and the safety of the vehicle, a driver and passengers is ensured.
In some embodiments, the first sampling switch unit includes: and the first sampling switch and the first capacitor are arranged between the first sampling resistor and the first voltage dividing resistor unit in parallel. The second sampling switch unit includes: and the second sampling switch and the second capacitor are arranged between the second sampling resistor and the second voltage dividing resistor unit in parallel.
Through the control unit, control the switch of first sampling switch unit and second sampling switch unit, include:
and controlling the first sampling switch to be switched on and controlling the second sampling switch to be switched off. Specifically, take bus positive BAT + loop as an example, close switch Ks1And a disconnecting switch Ks2。
Detecting, by a detection unit, a first sampling voltage across the first sampling resistor under a condition that switches of the first sampling switch unit and the second sampling switch unit are controlled, including:
and under the condition that the first sampling switch is switched on and the second sampling switch is switched off, detecting a first sampling voltage on the first sampling resistor. In particular, the switch K is closeds1And a disconnecting switch Ks2Detecting the sampling resistance Rs1Voltage U ons1。
Thus, the sampling resistor R is judged by first passings1Upper sampled voltage Us1And different control logics are executed according to the judgment result, so that the problems that the insulation detection fault cannot be identified and the fault point can not be accurately positioned are solved, and the fault can be quickly identified and the fault point can be accurately positioned.
In some embodiments, determining, by the control unit, whether the first sampling resistor and/or the first voltage dividing resistor unit is failed according to the first sampling voltage is the same as determining whether the second sampling resistor and/or the second voltage dividing resistor unit is failed according to the second sampling voltage.
In some embodiments, determining, by the control unit, whether the first sampling resistor and/or the first divider resistor unit is malfunctioning based on the first sampling voltage includes any one of the following determination situations:
the first determination case: and if the first sampling voltage is 0, determining that the first sampling resistor has a short-circuit fault.
Specifically, take bus positive BAT + loop as an example, close switch Ks1And a disconnecting switch Ks2Detecting the sampling resistance Rs1Voltage U ons1If voltage Us1If 0, the sampling resistance R is describeds1And (4) short-circuiting.
Second determination case: and if the first sampling voltage is not 0 and is smaller than a first calculation coefficient multiple of the first insulation voltage on the first insulation resistor, determining that the first voltage dividing resistor unit has a short-circuit fault, and determining a fault point of the first voltage dividing resistor unit. The first calculation coefficient is a ratio of the resistance of the first sampling resistor to the sum of the resistance of the first sampling resistor and the resistance of the first divider resistor unit.
Specifically, take bus positive BAT + loop as an example, close switch Ks1And a disconnecting switch Ks2Detecting the sampling resistance Rs1Voltage U ons1If voltage Us1Not equal to 0, and
Figure BDA0002810844470000191
then the voltage dividing resistor R is indicatedp1....RpnOne or more of which are short circuited.
The third determination scenario: and if the first sampling voltage is not 0 and is equal to a first calculation coefficient multiple of the first insulation voltage on the first insulation resistor, determining that the insulation resistor detection circuit is normal, namely determining that the insulation resistor detection circuit has no fault.
Specifically, take bus positive BAT + loop as an example, close switch Ks1And a disconnecting switch Ks2Detecting the sampling resistance Rs1Voltage U ons1If voltage Us1Not equal to 0, and
Figure BDA0002810844470000192
the insulation detection circuit is normal.
Therefore, only the sampling resistor R needs to be detecteds1Voltage U ons1Whether the insulation detection circuit is in fault can be identified according to the sampling voltage Us1Different control logic is executed, and the fault position can be located. Therefore, whether the insulation resistance detection circuit is abnormal or not can be judged, and the insulation performance of the whole vehicle is ensured; can accurately detect the position and the number of the short-circuit resistors and can be used according to the number of the short-circuit resistorsDifferent protections are carried out, and meanwhile, faults are conveniently and quickly identified for maintenance; the control mode is simple, the response speed is high, and the cost is low.
In some embodiments, further comprising: a first voltage division switch unit arranged corresponding to the first voltage division resistor unit is arranged; the first voltage dividing resistance unit includes: the first voltage dividing resistor to the nth voltage dividing resistor are connected in series; the first voltage division switching unit includes: first to nth voltage dividing switches; each voltage division switch is connected in parallel with two ends of a corresponding voltage division resistor; n is a positive integer.
Of course, the second voltage dividing resistor unit R can be includedn1、....、RnnCorrespondingly arranged second voltage-dividing switch units, e.g. Kn1、....、Knn。
Referring to the example shown in FIG. 2, at the voltage dividing resistor Rp1、....、Rpn、 and Rn1、....、RnnIn parallel with a switch on each voltage dividing resistor, i.e. in voltage dividing resistor Rp1、....、RpnUpper parallel switch Kp1、....、KpnAt the voltage dividing resistor Rn1、....、RnnUpper parallel switch Kn1、....、KnnAnd the method is used for positioning the fault position.
Determining, by a control unit, a failure point of the first voltage dividing resistance unit, including:
if the first sampling voltage is a second calculation coefficient multiple of the first insulation voltage on the first insulation resistor, and the value of the first sampling voltage is kept unchanged after m voltage division switches from the first voltage division switch to the nth voltage division switch are closed, determining that m voltage division resistors connected in parallel with the m voltage division switches are short-circuited, namely determining that the fault point of the first voltage division resistor unit is the fault that m voltage division resistors connected in parallel with the m voltage division switches are short-circuited. The second calculation coefficient is the ratio of the resistance of the first sampling resistor to the sum of the resistances of the remaining divider resistors, and m is greater than or equal to 1 and less than or equal to n. The rest voltage-dividing resistors are the rest voltage-dividing resistors except the m voltage-dividing resistors in the n voltage-dividing resistors.
For example: if the first sampling voltage is a first calculation coefficient multiple of the first insulation voltage on the first insulation resistor, and the value of the first sampling voltage is kept unchanged after the first voltage division switch is closed, determining that the first voltage division resistor has a short-circuit fault, namely determining that the fault point of the first voltage division resistor unit is the fault that the first voltage division resistor has a short-circuit fault. The first calculation coefficient is a ratio of the resistance value of the first sampling resistor to the sum of the resistance values of the second to nth divider resistors.
In particular, suppose Rp1Short circuit at this time
Figure BDA0002810844470000201
Closing switch Kp1Voltage Us1Remain unchanged.
Let R bep1Short circuit at this time
Figure BDA0002810844470000202
Closing switch Kp1Voltage Us1Remain unchanged.
Let R bepnShort circuit at this time
Figure BDA0002810844470000203
Closing switch KpnVoltage Us1Remain unchanged.
Suppose a voltage dividing resistor Rp1 and Rp2At the same time short-circuited, at this time
Figure BDA0002810844470000204
Simultaneous closing of switches Kp1And switch Kp2Voltage Us1Remain unchanged.
Suppose a voltage dividing resistor Rp1、Rp2 and Rp3At the same time short-circuited, at this time
Figure BDA0002810844470000205
Simultaneous closing of switches Kp1、Kp2 and Kp3Voltage Us1Remain unchanged.
Therefore, the situation that the short circuit of the resistors occurs can be detected simultaneously under the condition that the short circuit fault of the voltage division resistor unit is determined, the fault position is accurately positioned, and the reliability of the insulation detection circuit is improved.
Since the processing and functions implemented by the method of this embodiment substantially correspond to the embodiments, principles and examples of the automobile, reference may be made to the related descriptions in the foregoing embodiments without being detailed in the description of this embodiment, which is not described herein.
Through a large number of tests, the technical scheme of the embodiment is adopted, and whether the insulation resistor is short-circuited or not can be determined by detecting the voltage on the insulation resistor; the detection switch is arranged at the position of the insulation resistor in the insulation detection circuit, so that the fault position of the insulation resistor can be positioned, whether the insulation resistance detection circuit is abnormal or not can be judged, and the insulation performance of the whole vehicle is ensured; the position and the quantity of the short-circuit resistors can be accurately detected, different protections are carried out according to the number of the short-circuit resistors, and meanwhile, faults can be conveniently and quickly identified for maintenance.
In summary, it is readily understood by those skilled in the art that the advantageous modes described above can be freely combined and superimposed without conflict.
The above description is only an example of the present invention, and is not intended to limit the present invention, and it is obvious to those skilled in the art that various modifications and variations can be made in the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims (11)

1. A fault diagnosis device of an insulation resistance detection circuit of an automobile, characterized in that the insulation resistance detection circuit includes: a first sampling resistor and a first divider resistor unit connected to a positive electrode of the battery pack of the automobile, and a second sampling resistor and a second divider resistor unit connected to a negative electrode of the battery pack of the automobile; the first sampling resistor is connected with the second sampling resistor;
the fault diagnosis device for the insulation resistance detection circuit of the automobile comprises: the device comprises a first sampling switch unit, a second sampling switch unit, a detection unit and a control unit; the first sampling switch unit is arranged between the first sampling resistor and the first voltage dividing resistor unit; the second sampling switch unit is arranged between the second sampling resistor and the second voltage dividing resistor unit; wherein,
the control unit configured to control switching of the first sampling switching unit and the second sampling switching unit;
the detection unit is configured to sample a first sampling voltage on the first sampling resistor and sample a second sampling voltage on the second sampling resistor under the condition of controlling the switches of the first sampling switch unit and the second sampling switch unit;
the control unit is further configured to determine whether the first sampling resistor and/or the first divider resistor unit fails according to the first sampling voltage, so as to prompt and protect in case of failure of the first sampling resistor and/or the first divider resistor unit;
and determining whether the second sampling resistor and/or the second voltage dividing resistor unit has a fault according to the second sampling voltage so as to prompt and protect under the condition that the second sampling resistor and/or the second voltage dividing resistor unit has a fault.
2. The apparatus according to claim 1, wherein the control unit determines whether the first sampling resistor and/or the first dividing resistor unit is defective based on the first sampling voltage in the same manner as the second sampling resistor and/or the second dividing resistor unit is defective based on the second sampling voltage.
3. The fault diagnosis device of the insulation resistance detection circuit of the automobile according to claim 1 or 2, wherein the first sampling switch unit includes: a first sampling switch and a first capacitor which are arranged between the first sampling resistor and the first voltage dividing resistor unit in parallel; the second sampling switch unit includes: the second sampling switch and the second capacitor are arranged between the second sampling resistor and the second voltage dividing resistor unit in parallel;
the control unit controls the switches of the first sampling switch unit and the second sampling switch unit, and includes:
controlling the first sampling switch to be switched on and controlling the second sampling switch to be switched off;
the detection unit, under the condition of controlling the switch of the first sampling switch unit and the second sampling switch unit, detects the first sampling voltage on the first sampling resistor, and includes:
and under the condition that the first sampling switch is switched on and the second sampling switch is switched off, detecting a first sampling voltage on the first sampling resistor.
4. The apparatus of claim 3, wherein the control unit determines whether the first sampling resistor and/or the first dividing resistor unit is faulty according to the first sampling voltage, and comprises:
if the first sampling voltage is 0, determining that the first sampling resistor has a short-circuit fault;
if the first sampling voltage is not 0 and is smaller than a first calculation coefficient multiple of a first insulation voltage on a first insulation resistor, determining that the first voltage dividing resistor unit has a short-circuit fault, and determining a fault point of the first voltage dividing resistor unit; the first calculation coefficient is the ratio of the resistance value of the first sampling resistor to the sum of the resistance values of the first divider resistor unit;
and if the first sampling voltage is not 0 and is equal to a first calculation coefficient multiple of the first insulation voltage on the first insulation resistor, determining that the insulation resistor detection circuit is normal.
5. The apparatus for diagnosing a fault in an insulation resistance detection circuit of an automobile according to claim 4, further comprising: a first voltage division switch unit; the first voltage dividing resistance unit includes: the first voltage dividing resistor to the nth voltage dividing resistor are connected in series; the first voltage division switching unit includes: first to nth voltage dividing switches; each voltage division switch is connected in parallel with two ends of a corresponding voltage division resistor; n is a positive integer;
the control unit, which determines the failure point of the first voltage dividing resistance unit, includes:
if the first sampling voltage is a second calculation coefficient multiple of the first insulation voltage on the first insulation resistor, and the value of the first sampling voltage is kept unchanged after m voltage division switches from the first voltage division switch to the nth voltage division switch are closed, determining that m voltage division resistors connected with the m voltage division switches in parallel have short-circuit faults; the second calculation coefficient is the ratio of the resistance of the first sampling resistor to the sum of the resistances of the remaining divider resistors, and m is greater than or equal to 1 and less than or equal to n.
6. An automobile, comprising: the fault diagnosis device of an insulation resistance detection circuit of an automobile according to any one of claims 1 to 5.
7. A fault diagnosis method for an insulation resistance detection circuit of an automobile, characterized in that the insulation resistance detection circuit includes: a first sampling resistor and a first divider resistor unit connected to a positive electrode of the battery pack of the automobile, and a second sampling resistor and a second divider resistor unit connected to a negative electrode of the battery pack of the automobile; the first sampling resistor is connected with the second sampling resistor;
the fault diagnosis method of the insulation resistance detection circuit of the automobile comprises the following steps:
the control unit controls the switches of the first sampling switch unit and the second sampling switch unit;
through a detection unit, under the condition of controlling the switches of the first sampling switch unit and the second sampling switch unit, sampling a first sampling voltage on the first sampling resistor, and sampling a second sampling voltage on the second sampling resistor;
determining whether the first sampling resistor and/or the first divider resistor unit has a fault or not according to the first sampling voltage through a control unit, so as to prompt and protect under the condition that the first sampling resistor and/or the first divider resistor unit has a fault;
and determining whether the second sampling resistor and/or the second voltage dividing resistor unit has a fault according to the second sampling voltage so as to prompt and protect under the condition that the second sampling resistor and/or the second voltage dividing resistor unit has a fault.
8. The method according to claim 7, wherein the control unit determines whether the first sampling resistor and/or the first divider resistor unit is defective based on the first sampling voltage in the same manner as the second sampling resistor and/or the second divider resistor unit is defective based on the second sampling voltage.
9. The method for diagnosing a fault of an insulation resistance detection circuit of an automobile according to claim 7 or 8, wherein the first sampling switch unit includes: a first sampling switch and a first capacitor which are arranged between the first sampling resistor and the first voltage dividing resistor unit in parallel; the second sampling switch unit includes: the second sampling switch and the second capacitor are arranged between the second sampling resistor and the second voltage dividing resistor unit in parallel;
through the control unit, control the switch of first sampling switch unit and second sampling switch unit, include:
controlling the first sampling switch to be switched on and controlling the second sampling switch to be switched off;
detecting, by a detection unit, a first sampling voltage across the first sampling resistor under a condition that switches of the first sampling switch unit and the second sampling switch unit are controlled, including:
and under the condition that the first sampling switch is switched on and the second sampling switch is switched off, detecting a first sampling voltage on the first sampling resistor.
10. The method of claim 9, wherein determining, by the control unit, whether the first sampling resistor and/or the first dividing resistor unit is faulty according to the first sampling voltage includes:
if the first sampling voltage is 0, determining that the first sampling resistor has a short-circuit fault;
if the first sampling voltage is not 0 and is smaller than a first calculation coefficient multiple of a first insulation voltage on a first insulation resistor, determining that the first voltage dividing resistor unit has a short-circuit fault, and determining a fault point of the first voltage dividing resistor unit; the first calculation coefficient is the ratio of the resistance value of the first sampling resistor to the sum of the resistance values of the first divider resistor unit;
and if the first sampling voltage is not 0 and is equal to a first calculation coefficient multiple of the first insulation voltage on the first insulation resistor, determining that the insulation resistor detection circuit is normal.
11. The method of diagnosing a fault in an insulation resistance detection circuit of an automobile according to claim 10, further comprising:
determining, by a control unit, a failure point of the first voltage dividing resistance unit, including:
if the first sampling voltage is a second calculation coefficient multiple of the first insulation voltage on the first insulation resistor, and the value of the first sampling voltage is kept unchanged after m voltage division switches from the first voltage division switch to the nth voltage division switch are closed, determining that m voltage division resistors connected with the m voltage division switches in parallel have short-circuit faults; the second calculation coefficient is the ratio of the resistance of the first sampling resistor to the sum of the resistances of the remaining divider resistors, and m is greater than or equal to 1 and less than or equal to n.
CN202011389612.6A 2020-12-01 2020-12-01 Fault diagnosis device and method for insulation resistance detection circuit of automobile and automobile Active CN112659898B (en)

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