CN114295945B - Insulation detection method, device and system - Google Patents
Insulation detection method, device and system Download PDFInfo
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- CN114295945B CN114295945B CN202111642783.XA CN202111642783A CN114295945B CN 114295945 B CN114295945 B CN 114295945B CN 202111642783 A CN202111642783 A CN 202111642783A CN 114295945 B CN114295945 B CN 114295945B
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- 238000009413 insulation Methods 0.000 title claims abstract description 231
- 238000001514 detection method Methods 0.000 title claims abstract description 112
- 238000005070 sampling Methods 0.000 claims abstract description 226
- 238000000034 method Methods 0.000 description 7
- 238000010586 diagram Methods 0.000 description 6
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 1
- 230000008707 rearrangement Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/60—Other road transportation technologies with climate change mitigation effect
- Y02T10/70—Energy storage systems for electromobility, e.g. batteries
Abstract
The embodiment of the invention discloses an insulation detection method, an insulation detection device and an insulation detection system. The insulation detection method comprises the following steps: acquiring voltages at two ends of a first sampling resistor and voltages at two ends of a second sampling resistor in a preset time and after the preset time; the first sampling resistor and the second sampling resistor are electrically connected with the battery pack; if the output current of the battery pack after the preset time is in a first preset range, controlling the on-off state of a loop where the battery pack is positioned according to the voltage at the two ends of the first sampling resistor and the voltage at the two ends of the second sampling resistor after the preset time; if the output current of the battery pack after the preset time is in the second preset range, determining the insulation state of the battery pack according to the voltages at the two ends of the first sampling resistor and the voltages at the two ends of the second sampling resistor in the preset time and after the preset time. The technical scheme provided by the embodiment of the invention can improve the reliability of insulation detection.
Description
Technical Field
The embodiment of the invention relates to an insulation detection technology, in particular to an insulation detection method, an insulation detection device and an insulation detection system.
Background
Vehicles such as automated guided vehicles, which are equipped with an electromagnetic or optical automated guide device capable of traveling along a predetermined guide path and have safety protection and various transfer functions, are increasingly used, and a battery pack is one of important components of the automated guided vehicles. If the battery pack has insulation faults due to unreliable insulation detection, the battery pack, even the whole vehicle and personal safety can be affected.
At present, in the existing insulation detection method, related data are generally collected after a battery pack starts to work for insulation detection, the collected data and the insulation detection are not time-differentiated, and the reliability of an insulation detection result obtained by the insulation detection mode needs to be improved.
Disclosure of Invention
The embodiment of the invention provides an insulation detection method, an insulation detection device and an insulation detection system, which are used for improving the reliability of insulation detection.
In a first aspect, an embodiment of the present invention provides an insulation detection method, where the insulation detection method is used for performing insulation detection on a battery pack of a vehicle, and the insulation detection method includes:
acquiring voltages at two ends of a first sampling resistor and voltages at two ends of a second sampling resistor in a preset time and after the preset time; the first sampling resistor and the second sampling resistor are electrically connected with the battery pack;
if the output current of the battery pack after the preset time is in a first preset range, controlling the on-off state of a loop where the battery pack is positioned according to the voltage at the two ends of the first sampling resistor and the voltage at the two ends of the second sampling resistor after the preset time;
if the output current of the battery pack after the preset time is in the second preset range, determining the insulation state of the battery pack according to the voltages at the two ends of the first sampling resistor and the voltages at the two ends of the second sampling resistor in the preset time and after the preset time.
Optionally, the branch where the first sampling resistor is located has a first switch, and the branch where the second sampling resistor is located has a second switch;
acquiring the voltage at two ends of the first sampling resistor and the voltage at two ends of the second sampling resistor in the preset time and after the preset time comprises the following steps:
acquiring voltages at two ends of a first sampling resistor and voltages at two ends of a second sampling resistor in a first state, a second state and a third state within preset time, and acquiring the voltages at two ends of the first sampling resistor and the voltages at two ends of the second sampling resistor in the first state, the second state and the third state after the preset time; the first state is a state that both the first switch and the second switch are closed, the second state is a state that the first switch is closed and the second switch is opened, and the third state is a state that the first switch is opened and the second switch is closed.
Optionally, the first end of the branch where the first sampling resistor is located is electrically connected with the positive electrode of the battery pack, the second end of the branch where the first sampling resistor is located is grounded, the first end of the branch where the second sampling resistor is located is electrically connected with the negative electrode of the battery pack, and the second end of the branch where the second sampling resistor is located is grounded.
Optionally, controlling the on-off state of the loop where the battery pack is located according to the voltage at both ends of the first sampling resistor and the voltage at both ends of the second sampling resistor after the preset time includes:
according to the voltage at the two ends of the first sampling resistor and the voltage at the two ends of the second sampling resistor after the preset time, if the resistance value of the insulation resistor of the battery pack is determined to be larger than a preset threshold value, the on-off state of a loop where the battery pack is positioned is controlled to be unchanged;
and according to the voltages at the two ends of the first sampling resistor and the voltages at the two ends of the second sampling resistor after the preset time, if the resistance value of the insulation resistor is smaller than the preset threshold value, the loop where the battery pack is located is controlled to be disconnected.
Optionally, determining the insulation state of the battery pack according to the voltage across the first sampling resistor and the voltage across the second sampling resistor within the preset time and after the preset time includes:
determining a first insulation state of the battery pack within a preset time according to the voltages at the two ends of the first sampling resistor and the voltages at the two ends of the second sampling resistor within the preset time;
determining a second insulation state of the battery pack after the preset time according to the voltage at the two ends of the first sampling resistor and the voltage at the two ends of the second sampling resistor after the preset time;
and performing logical AND operation on the first insulation state and the second insulation state according to the first insulation state and the second insulation state to determine the final insulation state of the battery pack.
Optionally, after obtaining the voltages at both ends of the first sampling resistor and the voltages at both ends of the second sampling resistor within the preset time and after the preset time, the method includes:
and obtaining the output current of the battery pack after the preset time.
Optionally, the preset time is 30s.
In a second aspect, an embodiment of the present invention further provides an insulation detection device, where the insulation detection device is used for performing insulation detection on a battery pack of a vehicle, and the insulation detection device includes:
the voltage acquisition module is used for acquiring the voltages at two ends of the first sampling resistor and the voltages at two ends of the second sampling resistor in a preset time and after the preset time; the first sampling resistor and the second sampling resistor are electrically connected with the battery pack;
the on-off state control module is used for controlling the on-off state of a loop where the battery pack is located according to the voltage at two ends of the first sampling resistor and the voltage at two ends of the second sampling resistor after the preset time if the output current of the battery pack after the preset time is in a first preset range;
and the insulation state detection module is used for determining the insulation state of the battery pack according to the voltage at two ends of the first sampling resistor and the voltage at two ends of the second sampling resistor in the preset time and after the preset time if the output current of the battery pack after the preset time is in the second preset range.
In a third aspect, an embodiment of the present invention further provides an insulation detection system, including: the battery pack, the controller and the insulation detection circuit are electrically connected with the insulation detection circuit, and the insulation detection device according to any embodiment of the invention is integrated in the controller.
Optionally, the insulation detection circuit includes a first sampling resistor, a second sampling resistor, a first switch and a second switch; the first sampling resistor is connected with the first switch in series, the first sampling resistor and the first switch are both positioned in the first branch, the second sampling resistor is connected with the second switch in series, and the second sampling resistor and the second switch are both positioned in the second branch; the first end of the first branch is electrically connected with the positive electrode of the battery pack, the second end of the first branch is grounded, the first end of the second branch is electrically connected with the negative electrode of the battery pack, and the second end of the second branch is grounded.
According to the insulation detection method, device and system provided by the embodiment of the invention, the voltages at the two ends of the first sampling resistor and the voltages at the two ends of the second sampling resistor are obtained within the preset time and after the preset time; the first sampling resistor and the second sampling resistor are electrically connected with the battery pack; if the output current of the battery pack after the preset time is in a first preset range, controlling the on-off state of a loop where the battery pack is positioned according to the voltage at the two ends of the first sampling resistor and the voltage at the two ends of the second sampling resistor after the preset time; if the output current of the battery pack after the preset time is in the second preset range, determining the insulation state of the battery pack according to the voltages at the two ends of the first sampling resistor and the voltages at the two ends of the second sampling resistor in the preset time and after the preset time. According to the insulation detection method, device and system provided by the embodiment of the invention, the insulation state of the battery pack is determined according to the voltage at the two ends of the first sampling resistor and the voltage at the two ends of the second sampling resistor in the preset time and after the preset time, the insulation detection can be ensured in the preset time, the insulation state of the battery pack is determined by combining the insulation detection after the preset time, and the reliability of the insulation detection can be improved.
Drawings
Fig. 1 is a flowchart of an insulation detection method according to a first embodiment of the present invention;
fig. 2 is a flowchart of an insulation detection method according to a second embodiment of the present invention;
fig. 3 is a block diagram of an insulation detection device according to a third embodiment of the present invention;
fig. 4 is a schematic structural diagram of an insulation detection circuit according to a fourth embodiment of the present invention;
fig. 5 is a block diagram of a controller according to a fourth embodiment of the present invention.
Detailed Description
The invention is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present invention are shown in the drawings.
Example 1
Fig. 1 is a flowchart of an insulation detection method provided in an embodiment of the present invention, where the embodiment is applicable to situations such as insulation detection of a battery pack of a vehicle, and the method may be performed by an insulation detection device in an insulation detection system, where the device may be implemented by software and/or hardware, and where the device may be integrated into a controller having an insulation detection function, and the method specifically includes the following steps:
step 110, obtaining the voltages at two ends of the first sampling resistor and the voltages at two ends of the second sampling resistor within and after the preset time.
The preset time may be a preset time after the battery pack starts to work, i.e. after the vehicle is electrified, for example, 30s, and the first sampling resistor and the second sampling resistor are electrically connected with the battery pack. The controller may be connected to both ends of the first sampling resistor and both ends of the second sampling resistor to obtain voltages at both ends of the first sampling resistor and voltages at both ends of the second sampling resistor. In addition, the output current of the battery pack after the preset time can be obtained after the voltage is obtained.
And step 120, if the output current of the battery pack after the preset time is within a first preset range, controlling the on-off state of a loop where the battery pack is located according to the voltage at both ends of the first sampling resistor and the voltage at both ends of the second sampling resistor after the preset time.
For example, after the battery pack starts to work, that is, the vehicle is powered on for 30s, insulation detection is performed under a relatively static working condition, if the output current of the battery pack is less than 5A, according to the voltage at two ends of the first sampling resistor and the voltage at two ends of the second sampling resistor after the vehicle is powered on for 30s (approximately 30s, such as 35s or so), when the resistance value of the insulation resistor of the battery pack is determined to be less than a preset threshold value, that is, insulation failure occurs, the loop where the battery pack is located is controlled to be disconnected, and the loop is cut off in time, so that accidents caused by the insulation failure are prevented.
And 130, if the output current of the battery pack after the preset time is within a second preset range, determining the insulation state of the battery pack according to the voltages at the two ends of the first sampling resistor and the voltages at the two ends of the second sampling resistor within the preset time and after the preset time.
For example, after the battery pack starts to work, i.e. the vehicle is powered on for 30s, insulation detection is performed under a relatively static working condition, and if the output current of the battery pack is greater than 5A and less than 0.15C, the insulation state of the battery pack is determined according to the voltages at the two ends of the first sampling resistor and the voltage at the two ends of the second sampling resistor in the vehicle powered on for 30s, and the voltages at the two ends of the first sampling resistor and the voltage at the two ends of the second sampling resistor after the vehicle is powered on for 30s (approximately 30s, such as about 35 s). Specifically, if the insulation fault of the battery pack in the vehicle power-on 30s is determined according to the voltages of the two ends of the first sampling resistor and the voltages of the two ends of the second sampling resistor in the vehicle power-on 30s, and the insulation fault of the battery pack after the vehicle power-on 30s is determined according to the voltages of the two ends of the first sampling resistor and the voltages of the two ends of the second sampling resistor after the vehicle power-on 30s, the insulation fault of the battery pack is determined, at the moment, the port of the loop where the battery pack is located can be controlled, the loop where the battery pack is located is cut off in time, corresponding prompt information is sent, and accidents are prevented.
According to the insulation detection method provided by the embodiment, the voltages at the two ends of the first sampling resistor and the voltages at the two ends of the second sampling resistor are obtained within the preset time and after the preset time; the first sampling resistor and the second sampling resistor are electrically connected with the battery pack; if the output current of the battery pack after the preset time is in a first preset range, controlling the on-off state of a loop where the battery pack is positioned according to the voltage at the two ends of the first sampling resistor and the voltage at the two ends of the second sampling resistor after the preset time; if the output current of the battery pack after the preset time is in the second preset range, determining the insulation state of the battery pack according to the voltages at the two ends of the first sampling resistor and the voltages at the two ends of the second sampling resistor in the preset time and after the preset time. According to the insulation detection method provided by the embodiment, the insulation state of the battery pack is determined according to the voltage at the two ends of the first sampling resistor and the voltage at the two ends of the second sampling resistor in the preset time and after the preset time, insulation detection can be guaranteed in the preset time, the insulation state of the battery pack is determined by combining the insulation detection after the preset time, and the reliability of the insulation detection can be improved.
Example two
Fig. 2 is a flowchart of an insulation detection method provided in a second embodiment of the present invention, where the method may be applied to situations such as insulation detection of a battery pack of a vehicle, and the method may be performed by an insulation detection device in an insulation detection system, where the device may be implemented by software and/or hardware, and where the device may be integrated into a controller having an insulation detection function, and the method specifically includes the following steps:
step 210, obtaining voltages at two ends of the first sampling resistor and voltages at two ends of the second sampling resistor in the first state, the second state and the third state within a preset time, and obtaining voltages at two ends of the first sampling resistor and voltages at two ends of the second sampling resistor in the first state, the second state and the third state after the preset time.
The branch circuit where the first sampling resistor is located is provided with a first switch, and the branch circuit where the second sampling resistor is located is provided with a second switch. The first state is the closed state of the first switch and the second switch, the second state is the closed state of the first switch and the open state of the second switch, and the third state is the open state of the first switch and the closed state of the second switch.
The first end of the branch where the first sampling resistor is located is electrically connected with the positive electrode of the battery pack, the second end of the branch where the first sampling resistor is located is grounded, the first end of the branch where the second sampling resistor is located is electrically connected with the negative electrode of the battery pack, and the second end of the branch where the second sampling resistor is located is grounded. Specifically, the voltage at two ends of the first sampling resistor and the voltage at two ends of the second sampling resistor when the first switch and the second switch are both closed are obtained within a preset time such as 30s after the battery pack starts to work, namely, the vehicle is electrified, and after the vehicle is electrified for a preset time such as 30s (approximately 30s is approximately 35 s), the voltage at two ends of the first sampling resistor and the voltage at two ends of the second sampling resistor when the first switch is closed, the voltage at two ends of the first sampling resistor and the voltage at two ends of the second sampling resistor when the second switch is opened, and the voltage at two ends of the first sampling resistor and the voltage at two ends of the second sampling resistor when the first switch is opened and the second switch is closed are obtained.
Step 220, according to the voltages at the two ends of the first sampling resistor and the voltages at the two ends of the second sampling resistor after the preset time, if the resistance value of the insulation resistor of the battery pack is determined to be larger than the preset threshold value, the on-off state of the loop where the battery pack is located is controlled to be unchanged.
Specifically, the resistance of the insulation resistor of the battery pack can be determined according to the voltages of the two ends of the first sampling resistor and the voltage of the two ends of the second sampling resistor, and the pre-stored resistance value of the first sampling resistor and the pre-stored resistance value of the second sampling resistor. If the resistance value of the insulation resistance of the battery pack is larger than the preset threshold value, the insulation condition of the battery pack is good, and the on-off state of a loop where the battery pack is located can be controlled to be unchanged.
Step 230, according to the voltage at both ends of the first sampling resistor and the voltage at both ends of the second sampling resistor after the preset time, if the resistance value of the insulation resistor is smaller than the preset threshold value, the loop where the battery pack is located is controlled to be disconnected.
Specifically, the resistance of the insulation resistor of the battery pack can be determined according to the resistance of the first sampling resistor and the resistance of the second sampling resistor. If the resistance value of the insulation resistance of the battery pack is smaller than the preset threshold value, the battery pack is indicated to be possibly subjected to insulation fault, and at the moment, a loop where the battery pack is located is required to be controlled to be disconnected, so that accidents caused by the insulation fault of the battery pack are prevented.
Step 240, determining a first insulation state of the battery pack within a preset time according to the voltage across the first sampling resistor and the voltage across the second sampling resistor within the preset time.
Specifically, the resistance of the insulation resistor of the battery pack in the preset time can be determined according to the voltages of the two ends of the first sampling resistor and the voltages of the two ends of the second sampling resistor in the preset time, and the pre-stored resistance value of the first sampling resistor and the pre-stored resistance value of the second sampling resistor. If the resistance value of the insulation resistance of the battery pack in the preset time is larger than the preset threshold value, the first insulation state is good in the insulation state of the battery pack in the preset time, and if the resistance value of the insulation resistance of the battery pack in the preset time is smaller than the preset threshold value, the first insulation state is that the battery pack has insulation faults in the preset time.
Step 250, determining a second insulation state of the battery pack after the preset time according to the voltage across the first sampling resistor and the voltage across the second sampling resistor after the preset time.
The determination of the second insulation state is the same as the determination of the first insulation state, and the specific determination of the second insulation state can refer to the determination of the first insulation state in step 240, which is not described herein.
Step 260, performing logical AND operation on the first insulation state and the second insulation state according to the first insulation state and the second insulation state, and determining the final insulation state of the battery pack.
Specifically, if the first insulation state and the second insulation state are both insulation faults, the battery pack can be determined to have insulation faults, at the moment, the port of the loop where the battery pack is located can be controlled, the loop where the battery pack is located is cut off in time, corresponding prompt information is sent out, and accidents are prevented.
According to the insulation detection method provided by the embodiment, the first insulation state and the second insulation state are subjected to logical AND operation according to the first insulation state and the second insulation state, the final insulation state of the battery pack is determined, insulation detection can be guaranteed within a preset time, the insulation state of the battery pack is determined by combining the insulation detection after the preset time, and the reliability of the insulation detection can be improved.
Example III
Fig. 3 is a block diagram of an insulation detection device according to a third embodiment of the present invention, the insulation detection device being configured to perform insulation detection on a battery pack of a vehicle, the insulation detection device including: a voltage acquisition module 310, an on-off state control module 320, and an insulation state detection module 330; the voltage obtaining module 310 is configured to obtain voltages at two ends of the first sampling resistor and voltages at two ends of the second sampling resistor within a preset time and after the preset time; the first sampling resistor and the second sampling resistor are electrically connected with the battery pack; the on-off state control module 320 is configured to control the on-off state of a loop in which the battery pack is located according to the voltage across the first sampling resistor and the voltage across the second sampling resistor after the preset time if the output current of the battery pack after the preset time is within the first preset range; the insulation state detection module 330 is configured to determine an insulation state of the battery pack according to the voltage across the first sampling resistor and the voltage across the second sampling resistor within the preset time and after the preset time if the output current of the battery pack after the preset time is within the second preset range.
On the basis of the embodiment, the branch where the first sampling resistor is located is provided with a first switch, and the branch where the second sampling resistor is located is provided with a second switch; the voltage acquisition module 310 includes a voltage acquisition unit, where the voltage acquisition unit is configured to acquire voltages across the first sampling resistor and voltages across the second sampling resistor in the first state, the second state, and the third state within a preset time, and acquire voltages across the first sampling resistor and voltages across the second sampling resistor in the first state, the second state, and the third state after the preset time; the first state is a state that both the first switch and the second switch are closed, the second state is a state that the first switch is closed and the second switch is opened, and the third state is a state that the first switch is opened and the second switch is closed.
In one embodiment, the on-off state control module 320 includes a first control unit and a second control unit; the first control unit is used for controlling the on-off state of a loop where the battery pack is located to be unchanged if the resistance value of the insulation resistor of the battery pack is determined to be larger than a preset threshold value according to the voltage at the two ends of the first sampling resistor and the voltage at the two ends of the second sampling resistor after the preset time; and the second control unit is used for controlling the disconnection of a loop where the battery pack is located if the resistance value of the insulation resistor is smaller than the preset threshold value according to the voltage at the two ends of the first sampling resistor and the voltage at the two ends of the second sampling resistor after the preset time.
Preferably, the insulation state detection module 330 includes a first state determination unit, a second state determination unit, and a state detection unit; the first state determining unit is used for determining a first insulation state of the battery pack in preset time according to the voltages at two ends of the first sampling resistor and the voltages at two ends of the second sampling resistor in preset time; the second state determining unit is used for determining a second insulation state of the battery pack after the preset time according to the voltage at the two ends of the first sampling resistor and the voltage at the two ends of the second sampling resistor after the preset time; the detection unit is used for carrying out logical AND operation on the first insulation state and the second insulation state according to the first insulation state and the second insulation state, and determining the final insulation state of the battery pack.
Optionally, the insulation detection device further includes a current acquisition module, where the current acquisition module is configured to acquire, after the voltage acquisition module acquires the voltages at two ends of the first sampling resistor and the voltages at two ends of the second sampling resistor within a preset time and after the preset time, an output current of the battery pack after the preset time.
The insulation detection device provided by the embodiment and the insulation detection method provided by any embodiment of the invention belong to the same inventive concept, have corresponding beneficial effects, and the technical details not in detail in the embodiment are detailed in the insulation detection method provided by any embodiment of the invention.
Example IV
Fig. 4 is a schematic structural diagram of an insulation detection system according to a fourth embodiment of the present invention, where the insulation detection system includes: the battery pack 10, the controller 20 and the insulation detection circuit 30, wherein the battery pack 10 and the controller 20 are electrically connected with the insulation detection circuit 30, and the insulation detection device according to any embodiment of the invention is integrated in the controller 20.
The controller 20 performs insulation detection on the battery pack 10 through an insulation detection circuit 30, and a sampling resistor is provided in the insulation detection circuit 30. Specifically, the controller 20 may determine the resistance value of the insulation resistance of the battery pack 10 according to the voltage of the sampling resistor in the insulation detection circuit 30, and determine that the battery pack 10 has an insulation fault if the resistance value of the insulation resistance of the battery pack 10 is smaller than a preset resistance value.
Optionally, the insulation detection circuit 30 includes a first sampling resistor, a second sampling resistor, a first switch Kp, and a second switch Kn; the first sampling resistor Rsp is connected with the first switch Kp in series, the first sampling resistor Rsp and the first switch Kp are both positioned in the first branch, the second sampling resistor Rsn is connected with the second switch Kn in series, and the second sampling resistor Rsn and the second switch Kn are both positioned in the second branch; the first end of the first branch is electrically connected with the positive electrode of the battery pack 10, the second end of the first branch is grounded, the first end of the second branch is electrically connected with the negative electrode of the battery pack 10, and the second end of the second branch is grounded.
Fig. 5 is a block diagram illustrating a controller according to a fourth embodiment of the present invention, and referring to fig. 4 and 5, the controller 20 may perform single-end insulation detection and double-end insulation detection on the battery pack 10. The insulation detection principle is as follows: according to the voltage signal and the total voltage of the sampling resistor, insulation resistance calculation is periodically carried out, so that an insulation state is determined, and fault alarm is realized when insulation faults occur. The system calculates the magnitudes of the resistors Rp and Rn by changing the resistor network topology by controlling the combination of the states of the closing and opening of the switches Kp and Kn. When no insulation fault occurs, the voltages across sampling resistors Rsp and Rsn are substantially identical when both switches Kp and Kn are closed, but the voltages across sampling resistors Rsp and Rsn are both 0 when switch Kp is closed and switch Kn is open; when single-ended insulation leakage occurs, according to voltage signals of sampling resistors Rsp and Rsn when a switch Kp is closed and an switch Kn is closed, an independent equation is designed to calculate the size of the resistor Rp or Rn (the specific calculation process can refer to the prior art), and the insulation state is determined according to insulation fault grade judging conditions; when double-end insulation leakage occurs, according to the voltage signals of sampling resistors Rsp and Rsn when the switches Kp and Kn are both closed, and then according to the voltages Un of sampling resistors Rsp and Rsn and the total voltage of the battery pack 10 when the switches Kp are closed and Kn are open (or the switches Kp are open and Kn are closed), two independent equations can be designed through different resistor network distribution under the two combined states, and then the sizes of the resistors Rp and Rn can be calculated, and the insulation state of the battery pack 10 can be determined according to the insulation fault grade judging conditions. When it is determined that the battery pack 10 has an insulation fault, a prompt of the insulation fault can be sent out, insulation resistance values, namely the magnitudes of the resistors Rp and Rn and the insulation fault position can be output, and on-off of a positive/negative switch of an MOS tube electrically connected with the battery pack 10, an access state of an insulation power supply interface and the like can be controlled.
The insulation detection system provided by the embodiment and the insulation detection method provided by any embodiment of the invention belong to the same inventive concept, have corresponding beneficial effects, and the technical details not in detail in the embodiment are detailed in the insulation detection method provided by any embodiment of the invention.
Note that the above is only a preferred embodiment of the present invention and the technical principle applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, and that various obvious changes, rearrangements, combinations, and substitutions can be made by those skilled in the art without departing from the scope of the invention. Therefore, while the invention has been described in connection with the above embodiments, the invention is not limited to the embodiments, but may be embodied in many other equivalent forms without departing from the spirit or scope of the invention, which is set forth in the following claims.
Claims (9)
1. An insulation detection method for performing insulation detection on a battery pack of a vehicle, the insulation detection method comprising:
acquiring voltages at two ends of a first sampling resistor and voltages at two ends of a second sampling resistor in preset time and after the preset time; the preset time is the preset time after the vehicle is electrified, and the first sampling resistor and the second sampling resistor are electrically connected with the battery pack;
if the output current of the battery pack after the preset time is in a first preset range, controlling the on-off state of a loop where the battery pack is located according to the voltage at two ends of the first sampling resistor and the voltage at two ends of the second sampling resistor after the preset time;
if the output current of the battery pack after the preset time is in a second preset range, determining the insulation state of the battery pack according to the voltages at the two ends of the first sampling resistor and the voltages at the two ends of the second sampling resistor in the preset time and after the preset time;
the determining the insulation state of the battery pack according to the voltage at the two ends of the first sampling resistor and the voltage at the two ends of the second sampling resistor in the preset time and after the preset time comprises the following steps:
determining a first insulation state of the battery pack within a preset time according to the voltage at both ends of the first sampling resistor and the voltage at both ends of the second sampling resistor within the preset time;
determining a second insulation state of the battery pack after the preset time according to the voltage at the two ends of the first sampling resistor and the voltage at the two ends of the second sampling resistor after the preset time;
performing logical AND operation on the first insulation state and the second insulation state according to the first insulation state and the second insulation state, and determining the final insulation state of the battery pack;
if the first insulation state and the second insulation state are insulation faults, the battery pack can be determined to have insulation faults, at the moment, the port of the loop where the battery pack is located can be controlled, the loop where the battery pack is located is cut off in time, corresponding prompt information is sent out, and accidents are prevented.
2. The insulation detection method according to claim 1, wherein the branch where the first sampling resistor is located has a first switch, and the branch where the second sampling resistor is located has a second switch;
the obtaining the voltages at two ends of the first sampling resistor and the voltages at two ends of the second sampling resistor in the preset time and after the preset time comprises the following steps:
acquiring voltages at two ends of the first sampling resistor and the second sampling resistor in a first state, a second state and a third state within the preset time, and acquiring voltages at two ends of the first sampling resistor and the second sampling resistor in the first state, the second state and the third state after the preset time; the first state is a state that the first switch and the second switch are both closed, the second state is a state that the first switch is closed and the second switch is open, and the third state is a state that the first switch is open and the second switch is closed.
3. The insulation detection method according to claim 2, wherein a first end of the branch where the first sampling resistor is located is electrically connected to a positive electrode of the battery pack, a second end of the branch where the first sampling resistor is located is grounded, a first end of the branch where the second sampling resistor is located is electrically connected to a negative electrode of the battery pack, and the second end of the branch where the second sampling resistor is located is grounded.
4. The insulation detection method according to claim 1, wherein the controlling the on-off state of the loop in which the battery pack is located according to the voltage across the first sampling resistor and the voltage across the second sampling resistor after the preset time includes:
according to the voltage at the two ends of the first sampling resistor and the voltage at the two ends of the second sampling resistor after the preset time, if the resistance value of the insulation resistor of the battery pack is determined to be larger than a preset threshold value, the on-off state of a loop where the battery pack is positioned is controlled to be unchanged;
and according to the voltages at the two ends of the first sampling resistor and the voltages at the two ends of the second sampling resistor after the preset time, if the resistance value of the insulation resistor is smaller than a preset threshold value, controlling the circuit where the battery pack is located to be disconnected.
5. The insulation detection method according to claim 1, wherein the acquiring the voltage across the first sampling resistor and the voltage across the second sampling resistor within a preset time and after the preset time includes:
and obtaining the output current of the battery pack after the preset time.
6. The insulation detection method according to claim 1, wherein the preset time is 30s.
7. An insulation detection device for insulation detection of a battery pack of a vehicle, the insulation detection device comprising:
the voltage acquisition module is used for acquiring the voltages at two ends of the first sampling resistor and the voltages at two ends of the second sampling resistor in a preset time and after the preset time; the preset time is the preset time after the vehicle is electrified, and the first sampling resistor and the second sampling resistor are electrically connected with the battery pack;
the on-off state control module is used for controlling the on-off state of a loop where the battery pack is located according to the voltage at the two ends of the first sampling resistor and the voltage at the two ends of the second sampling resistor after the preset time if the output current of the battery pack after the preset time is in a first preset range;
the insulation state detection module is used for determining the insulation state of the battery pack according to the voltage at two ends of the first sampling resistor and the voltage at two ends of the second sampling resistor in the preset time and after the preset time if the output current of the battery pack after the preset time is in a second preset range;
determining an insulation state of the battery pack according to the voltage across the first sampling resistor and the voltage across the second sampling resistor within and after a preset time, comprising:
determining a first insulation state of the battery pack within a preset time according to the voltages at the two ends of the first sampling resistor and the voltages at the two ends of the second sampling resistor within the preset time;
determining a second insulation state of the battery pack after the preset time according to the voltage at the two ends of the first sampling resistor and the voltage at the two ends of the second sampling resistor after the preset time;
performing logical AND operation on the first insulation state and the second insulation state according to the first insulation state and the second insulation state, and determining the final insulation state of the battery pack;
if the first insulation state and the second insulation state are insulation faults, the battery pack can be determined to have insulation faults, at the moment, the port of the loop where the battery pack is located can be controlled, the loop where the battery pack is located is cut off in time, corresponding prompt information is sent out, and accidents are prevented.
8. An insulation detection system, comprising: the battery pack, the controller and the insulation detection circuit, wherein the battery pack and the controller are electrically connected with the insulation detection circuit, and the insulation detection device as claimed in claim 7 is integrated in the controller.
9. The insulation detection system of claim 8, wherein the insulation detection circuit comprises a first sampling resistor, a second sampling resistor, a first switch, and a second switch; the first sampling resistor is connected with the first switch in series, the first sampling resistor and the first switch are both positioned in a first branch, the second sampling resistor is connected with the second switch in series, and the second sampling resistor and the second switch are both positioned in a second branch; the first end of the first branch is electrically connected with the positive electrode of the battery pack, the second end of the first branch is grounded, the first end of the second branch is electrically connected with the negative electrode of the battery pack, and the second end of the second branch is grounded.
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