CN114076878A - Insulation detection method and device, control equipment and automobile - Google Patents
Insulation detection method and device, control equipment and automobile Download PDFInfo
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- CN114076878A CN114076878A CN202010818087.9A CN202010818087A CN114076878A CN 114076878 A CN114076878 A CN 114076878A CN 202010818087 A CN202010818087 A CN 202010818087A CN 114076878 A CN114076878 A CN 114076878A
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- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
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Abstract
The invention provides an insulation detection method, an insulation detection device, control equipment and an automobile, wherein the insulation detection method is applied to an insulation detection circuit of the automobile, the insulation detection circuit comprises a main positive relay, a main negative relay and a high-voltage bus ground insulation resistor which are connected with a power supply of the automobile, the insulation detection circuit also comprises an insulation detection relay and a voltage dividing resistor for insulation detection, and the insulation detection method comprises the following steps: controlling the vehicle to enter a corresponding sampling mode according to the working condition of the vehicle; wherein, the working conditions are different, and the corresponding sampling modes are different; controlling an insulation detection relay to be periodically switched on and off according to a sampling mode, and collecting voltage data; and calculating the insulation resistance of the high-voltage bus to the ground according to the voltage data. According to the scheme, different voltage sampling strategies are adopted according to different scenes of the vehicle, so that the insulation fault can be reported quickly; the anti-interference capability of the vehicle insulation detection function is enhanced, the accuracy of the whole vehicle insulation resistance calculation is improved, the reporting time is fast, and false alarm can be prevented.
Description
Technical Field
The invention relates to the field of automobiles, in particular to an insulation detection method, an insulation detection device, control equipment and an automobile.
Background
At present, the insulation detection of the electric automobile usually adopts a passive bridge method required by national standards, and although the method has high stability, the insulation resistance calculation and report are slow, and generally 30 seconds to 1 minute is required. The active insulation generally adopts a signal transmission mode to carry out insulation detection, the reporting speed of the insulation fault is high, and the insulation fault can be reported quickly within 1 to 5 seconds generally; the defect is that the stability is poor, and the false alarm condition is easily caused by the electromagnetic interference of a Y capacitor, a high-voltage component or a motor.
Disclosure of Invention
The embodiment of the invention provides an insulation detection method, an insulation detection device, control equipment and an automobile, and aims to solve the problem that the stability of an insulation detection method of an electric automobile in the prior art is not high or is long.
In order to solve the technical problems, the invention adopts the following technical scheme:
according to an aspect of the present invention, there is provided an insulation detection method applied to an insulation detection circuit of a vehicle, the insulation detection circuit including a main positive relay, a main negative relay, and a high-voltage bus ground insulation resistance connected to a power supply of the vehicle, and further including an insulation detection relay and a voltage dividing resistance for insulation detection, the insulation detection method including:
controlling the vehicle to enter a corresponding sampling mode according to the working condition of the vehicle; wherein, the working conditions are different, and the corresponding sampling modes are different;
controlling the insulation detection relay to be periodically switched on and off according to the sampling mode, and collecting voltage data; wherein the voltage data comprises a power supply positive electrode ground sampling voltage and a power supply negative electrode ground sampling voltage;
and calculating the insulation resistance of the high-voltage bus to the ground according to the voltage data.
Optionally, the controlling the vehicle to enter a corresponding sampling mode according to the working condition of the vehicle includes:
when the whole vehicle mode is a driving mode, if the speed of the vehicle is greater than a preset speed or the acceleration is greater than a preset acceleration, controlling the vehicle to enter a first voltage sampling mode; otherwise, controlling the vehicle to enter a second voltage sampling mode;
when the whole vehicle mode is a charging mode, the main negative relay is closed, and the main positive relay is disconnected, the vehicle is controlled to enter a first voltage sampling mode.
Optionally, the controlling the insulation detection relay to be periodically turned on and off according to the sampling mode and collecting voltage data includes:
controlling a first relay and a second relay in the insulation detection relays to be closed;
after the first relay and the second relay are closed for a first preset time, collecting the voltage of a first resistor in the voltage dividing resistor as a first voltage, collecting the voltage of a second resistor in the voltage dividing resistor as a second voltage, and controlling the second relay to be switched off;
after the second relay is disconnected for a second preset time, collecting the voltage of the first resistor as a third voltage, and controlling the second relay to be closed and the first relay to be disconnected;
collecting the voltage of the second resistor as a fourth voltage after the second relay is closed and the first relay is disconnected for the second preset time;
repeatedly executing the steps;
the sum of the first preset time and the second preset time is the switching period of the insulation detection relay, and the switching periods of different sampling modes are different.
Optionally, the controlling the vehicle to enter a corresponding sampling mode according to the working condition of the vehicle includes:
when the main and negative relays are powered on and closed on the whole vehicle, the vehicle is controlled to enter a third voltage sampling mode;
after the main positive relay is closed, the whole vehicle is electrified, and the vehicle is controlled to enter a first voltage sampling mode or a second voltage sampling mode according to the whole vehicle mode and the whole vehicle state of the vehicle;
the switching period of the first voltage sampling mode is greater than that of the second voltage sampling mode, and the switching period of the second voltage sampling mode is greater than that of the third voltage sampling mode.
Optionally, the calculating the insulation resistance of the high-voltage bus to ground according to the voltage data includes:
when the first voltage is larger than the second voltage, calculating the resistance value of a second insulation resistor in the high-voltage bus-to-ground insulation resistors according to a first functional relation among the first voltage, the second voltage, the third voltage and the first resistor; otherwise, calculating the resistance value of a first insulation resistor in the high-voltage bus to ground insulation resistors according to a second functional relation among the first voltage, the second voltage, the fourth voltage and the second resistor;
the first resistor is connected in parallel with the first insulation resistor, and the second resistor is connected in parallel with the second insulation resistor.
Optionally, the insulation detection method further includes:
reporting the resistance values of the first insulation resistor and the second insulation resistor every other preset reporting period;
the preset reporting period is an integral multiple of the sum of the first preset time and the two second preset times.
Optionally, the insulation detection method further includes:
and adjusting the preset reporting period according to the resistance values of the first insulation resistor and the second insulation resistor.
Optionally, the adjusting the preset reporting period according to the resistance values of the first insulation resistor and the second insulation resistor includes:
when the resistance value of any one of the first insulating resistor and the second insulating resistor is smaller than or equal to a first preset resistance value, adjusting the preset reporting period to be a first reporting period;
when the resistance values of the first insulation resistor and the second insulation resistor are both larger than the first preset resistance value, adjusting the preset reporting period to be a second reporting period;
wherein the first reporting period is less than the second reporting period.
Optionally, the insulation detection method further includes:
monitoring the voltage variation amplitude of the bus, and stopping reporting the resistance values of the first insulation resistor and the second insulation resistor when the voltage variation amplitude of the bus is larger than a voltage threshold.
Optionally, the insulation detection method further includes:
and reporting an insulation fault when the resistance value of any one of the first insulation resistor and the second insulation resistor is smaller than a second preset resistance value.
According to another aspect of the present invention, there is provided an insulation detecting apparatus applied to an insulation detecting circuit of a vehicle, the insulation detecting circuit including a main positive relay, a main negative relay, and a high-voltage bus ground insulation resistance connected to a power supply of the vehicle, and further including an insulation detecting relay and a voltage dividing resistance for insulation detection, the insulation detecting apparatus comprising:
the mode selection module is used for controlling the vehicle to enter a corresponding sampling mode according to the working condition of the vehicle; wherein, the working conditions are different, and the corresponding sampling modes are different;
the control processing module is used for controlling the insulation detection relay to be periodically switched on and off according to the sampling mode and collecting voltage data; wherein the voltage data comprises a power supply positive electrode ground sampling voltage and a power supply negative electrode ground sampling voltage;
and the insulation calculation module is used for calculating the insulation resistance of the high-voltage bus to the ground according to the voltage data.
According to another aspect of the present invention, there is provided a control apparatus comprising a memory, a processor, and a program stored on the memory and executable on the processor; the processor implements the insulation detection method as described above when executing the program.
According to another aspect of the present invention, there is provided an automobile including the insulation detection apparatus as described above.
The invention has the beneficial effects that:
according to the scheme, different voltage sampling strategies are adopted according to different scenes of the vehicle, so that the insulation fault can be reported quickly; the accuracy of whole car insulation resistance calculation is improved, and the report time is fast, and the interference killing feature is strong, can prevent the wrong report, and then has promoted customer experience.
Drawings
FIG. 1 is a schematic diagram of an insulation detection method according to an embodiment of the present invention;
FIG. 2 illustrates an insulation detection schematic provided by an embodiment of the present invention;
FIG. 3 is a timing diagram illustrating conventional bridge insulation detection;
FIG. 4 is a timing diagram of a sampling process of the insulation detection method according to an embodiment of the present invention;
FIG. 5 is a waveform diagram of a sampling voltage provided by an embodiment of the present invention;
FIG. 6 is a schematic diagram illustrating the detection of insulation in the slow charge pre-heat close main and negative relays according to an embodiment of the present invention;
FIG. 7 is a schematic diagram illustrating the detection of the insulation of the fast charge pre-heating closed main and negative relays according to the embodiment of the present invention;
fig. 8 is a schematic diagram illustrating a change in a bus voltage under a rapid acceleration condition according to an embodiment of the present invention;
FIG. 9 is a flow chart of an insulation detection method according to an embodiment of the present invention;
fig. 10 is a schematic view of an insulation detection apparatus 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 present invention will be described in detail with reference to the accompanying drawings and specific embodiments.
The invention provides an insulation detection method, an insulation detection device, control equipment and an automobile, aiming at the problem that the stability of the insulation detection method of the electric automobile is not high or is long.
As shown in fig. 1, one embodiment of the present invention provides an insulation detection method applied to an insulation detection circuit of a vehicle, the insulation detection circuit including a main positive relay Kp, a main negative relay Kn, and a high-voltage bus ground insulation resistor connected to a power supply of the vehicle, and further including an insulation detection relay and a voltage dividing resistor for insulation detection, the insulation detection method including:
s11: controlling the vehicle to enter a corresponding sampling mode according to the working condition of the vehicle; wherein, the working conditions are different, and the corresponding sampling modes are different;
s12: controlling the insulation detection relay to be periodically switched on and off according to the sampling mode, and collecting voltage data; wherein the voltage data comprises a power supply positive electrode ground sampling voltage and a power supply negative electrode ground sampling voltage;
s13: and calculating the insulation resistance of the high-voltage bus to the ground according to the voltage data.
It should be noted that the main positive relay Kp and the main negative relay Kn are respectively a positive relay and a negative relay of the vehicle power battery system, and both of them act according to the power-on sequence requirement of the entire vehicle. The embodiment of the invention adopts different sampling modes according to different working conditions of the vehicle, so that the whole vehicle insulation resistance (namely the ground insulation resistance of the high-voltage bus) of the vehicle can be calculated more timely and accurately.
Specifically, as shown in fig. 2, the insulation detection circuit includes: the power supply comprises a first insulation resistor Rp connected between the positive electrode of a power supply and the ground, a second insulation resistor Rn connected between the negative electrode of the power supply and the ground, and a first equivalent capacitor C connected with the first insulation resistor Rp in parallel1And a second equivalent capacitor C connected with the second insulation resistor Rn in parallel2。
The high-voltage bus ground insulation resistor comprises a first insulation resistor Rp and a second insulation resistor Rn, wherein the first insulation resistor Rp represents a high-voltage bus positive electrode ground chassis insulation resistor; the second insulation resistance Rn represents the insulation resistance of the negative electrode of the high-voltage bus to the electric chassis; first equivalent capacitor C1An equivalent Y capacitor and a second equivalent capacitor C for the positive bus to the electric chassis2The equivalent Y capacitor of the negative bus to the electric chassis, wherein the first equivalent capacitor C1The value of (A) is estimated as the sum of the positive poles of all the parts of the high-voltage system to the Y capacitance of the electric chassis, and the second equivalent capacitance C2The value of (c) is estimated as the sum of the negative poles of all the components of the high voltage system to the Y capacitance of the electrical chassis.
The insulation detection circuit further includes: a first resistor R0A second resistor R0', a first divider resistor R1A second voltage dividing resistor R3A first sampling resistor R2And a second sampling resistor R4(ii) a Wherein the first resistor R0In parallel with the first insulation resistor Rp, the first voltage dividing resistor R1And the first sampling resistor R2After being connected in series, the resistor is connected with the first insulation resistor Rp in parallel, and the first end of the first insulation resistor Rp and the first resistor R0First terminal of (1) and the first divider resistor R1Is connected with the first end of the first connecting pipe; the second resistor R0' in parallel with the second insulation resistance Rn, the second voltage-dividing resistance R3And the second sampling resistor R4After being connected in series, the resistor is connected with the second insulation resistor Rn in parallel, and the first end of the second insulation resistor Rn and the second resistor R0' the first terminal and the second voltage dividing resistor R3Is connected to the first end of the first housing.
The first resistor R is0A second resistor R0', a first divider resistor R1A second voltage dividing resistor R3A first sampling resistor R2And a second sampling resistor R4The resistance value of the detection resistor of the insulation detection circuit is a known value; a first resistor R0And a second resistor R0' known variable resistors can also be used;
a first relay S1 and a second relay S2; wherein, the first end of the first relay S1 is respectively connected with the first end of the first insulation resistor Rp and the first divider resistor R1Is connected to the first terminal of the first relay S1, and the second terminal of the first relay S1 is connected to the first resistor R0A first end of the second relay S2 is connected to a first end of the second insulation resistor Rn and the second voltage dividing resistor R, respectively3Is connected to the first terminal of the second relay S2, and the second terminal of the second relay S2 is connected to the second resistor R0The first end of the' is connected.
The first relay S1 and the second relay S2 are insulation detection relays, and the opening and closing thereof are controlled by a controller.
A main positive relay Kp and a main negative relay Kn; wherein the main positive relay Kp is connected toFirst voltage dividing resistor R1And said first equivalent capacitance C1Between the first terminals of (1), the first divider resistor R1Is connected with the positive electrode of the power supply, and the first equivalent capacitor C1The second terminal of (1) is grounded; the main negative relay Kn is connected with the second sampling resistor R4And said second equivalent capacitance C2Between the second terminals of the first and second sampling resistors R, the second sampling resistor R4The second end of the first capacitor is connected with the negative electrode of the power supply, and the second equivalent capacitor C2Is grounded.
Next, the following brief description is made for the vehicle insulation detection function of the conventional bridge method: generally, a first sampled voltage Up and a second sampled voltage Un need to be measured; wherein the first sampling voltage Up is R2Voltage sampling values at two ends, wherein the second sampling voltage Un is the voltage sampling value at two ends of R4;
when the vehicle is electrified at high voltage, after the power battery system closes the main negative relay Kn, if the high-voltage system is normally insulated, the current can pass through the positive pole of the power supply (R)0//(R1+R2) Or (R)1+R2) Flows through the second equivalent capacitor C2The loop formed to the negative electrode of the power supply is a second equivalent capacitor C2Charging, wherein measured values of a first sampling voltage Up and a second sampling voltage Un which are acquired after the circuit reaches a steady state are used for insulation resistance estimation; wherein (R)0//(R1+R2) Denotes the first voltage dividing resistor R when the first relay S1 is closed1And a first sampling resistor R2Connected in series and then connected with a first resistor R0Equivalent resistance connected in parallel; (R)1+R2) Indicating that the first voltage dividing resistor R is open when the first relay S1 is open1And a first sampling resistor R2Equivalent resistance after series connection;
similarly, if the main relay Kp is closed first, the current will pass through the power supply positive electrode via the first equivalent capacitor C1Flows through (R)0'//(R3+R4) Or (R)3+R4) The loop to the negative electrode of the power supply is the first equivalent capacitor C1Charging, first sampling power collected after reaching steady stateThe measured values of the voltage Up and the second sampling voltage Un are used for estimating the insulation resistance; wherein (R)0'//(R3+R4) Represents the second voltage dividing resistor R when the second relay S2 is closed3And a second sampling resistor R4Connected in series and then connected with a first resistor R0Equivalent resistance connected in parallel; (R)3+R4) When the second relay S2 is turned off, the second voltage dividing resistor R3And a second sampling resistor R4Equivalent resistance after series connection.
It should be noted that the time required for the circuit to reach the steady state can be calculated by a first formula:
t1＝3RC＝3max((R1+R2)C2，(R3+R4)C1)
the timing sequence requirement of the traditional bridge method insulation detection is shown in fig. 3, a main positive relay Kp and a main negative relay Kn are in a closed state, and a first equivalent capacitor C1And a second equivalent capacitor C2Reaching a steady state, when the first and second relays S1 and S2 are periodically opened or closed, the first equivalent capacitor C is at the moment when the first and second relays S1 and S2 are opened or closed1And a second equivalent capacitor C2The charging and discharging are carried out again, and the measured values of the first sampling voltage Up and the second sampling voltage Un are used for insulation resistance estimation after the circuit reaches a steady state;
according to the maximum design margin, using the first equivalent capacitance C1And a second equivalent capacitor C2The initial voltage is calculated as 0V, and the time required for the circuit to reach a steady state can be calculated by a second formula:
t2＝3RC＝3max((R0//(R1+R2))C2，(R0'//(R3+R4))C1)
according to the calculation results of the first formula and the second formula, the controller responsible for insulation detection needs to perform insulation estimation on the acquired measurement values of the first sampling voltage Up and the second sampling voltage Un only after the circuit fully reaches a steady state; according to the fact that the response stability time T of the circuit is 3RC, the smaller R is, the shorter the time required by the circuit to reach the stability is, and the method is slow in insulation resistance calculation and reporting, and generally needs 30 seconds to 1 minute.
Different from the conventional bridge method, the insulation detection method provided by one embodiment of the invention is optimized and improved on the basis of the bridge method, and different voltage sampling strategies are adopted for different scenes of a vehicle: if the main and negative relays Kn are only closed for insulation detection before the vehicle is powered on and in the charging and preheating processes, the insulation resistance of the whole vehicle can be monitored without connecting high voltage, so that the safety can be improved, and the safety of passengers can be ensured; aiming at the condition that customer complaints are caused by insulation faults easily occurring in the dynamic driving and charging processes, the stability of sampling voltage data is improved by adopting a strategy of increasing the switching period of an insulation detection relay or adjusting the reporting period of the insulation resistance of a vehicle, so that the generation of false alarm is prevented.
Specifically, the insulation detection method provided by one embodiment of the present invention is described as follows:
firstly, considering that the battery pack of the vehicle cannot be normally charged due to the fact that the temperature is too low, the battery pack is generally heated to a temperature suitable for charging before charging; that is to say, electric automobile is filling slowly or when filling soon, if the battery package temperature crosses lowly and has preheating the operating mode, fills electric pile and is connected with the heating circuit of whole car this moment to there is the high pressure, but the main positive relay Kp and the main negative relay Kn of battery package are in the off-state, and the unable external heating circuit that detects is insulating, has the risk of electrocuting.
Therefore, one embodiment of the present invention provides a control strategy for monitoring the insulation resistance of the entire vehicle under the battery preheating condition as follows:
as shown in fig. 6-7, in the preheating condition of the battery, the main negative relay Kn is closed and the main positive relay Kp is opened to monitor the insulation performance between the external charging pile and the heating loop of the whole vehicle.
Optionally, the controlling the vehicle to enter a corresponding sampling mode according to the working condition of the vehicle includes:
when the whole vehicle mode is a driving mode, if the speed of the vehicle is greater than a preset speed or the acceleration is greater than a preset acceleration, controlling the vehicle to enter a first voltage sampling mode; otherwise, controlling the vehicle to enter a second voltage sampling mode;
and when the whole vehicle mode is a charging mode, the main negative relay Kn is closed and the main positive relay Kp is disconnected, the vehicle is controlled to enter a first voltage sampling mode.
It should be noted that after the main positive relay Kp is closed, the whole vehicle is powered on; at the moment, according to the whole vehicle mode and the whole vehicle state of the vehicle, the mode of controlling the vehicle to enter is selected. The voltage sampling mode can be switched according to the monitoring of the vehicle speed and the acceleration in the dynamic driving process so as to adapt to the change of the working condition of the vehicle and prevent misinformation.
Optionally, the controlling the insulation detection relay to be periodically turned on and off according to the sampling mode and collecting voltage data includes:
controlling a first relay S1 and a second relay S2 of the insulation detection relays to be closed;
after the first relay S1 and the second relay S2 are closed for a first preset time, a first resistor R in the voltage dividing resistor is acquired0The voltage of the voltage divider is used as a first voltage, and a second resistor R in the voltage divider resistor is acquired0' as a second voltage and controls the second relay S2 to open;
collecting the first resistance R after the second relay S2 is switched off for a second preset time0As a third voltage and controls the second relay S2 to close and the first relay S1 to open;
collecting the second resistance R after the second relay S2 is closed and the first relay S1 is open for the second preset time0' as a fourth voltage;
repeatedly executing the steps;
the sum of the first preset time and the second preset time is the switching period of the insulation detection relay, and the switching periods of different sampling modes are different.
Optionally, the controlling the vehicle to enter a corresponding sampling mode according to the working condition of the vehicle includes:
when the main and negative relays Kn are powered on and closed on the whole vehicle, the vehicle is controlled to enter a third voltage sampling mode;
after the main positive relay Kp is closed, the whole vehicle is electrified, and the vehicle is controlled to enter a first voltage sampling mode or a second voltage sampling mode according to the whole vehicle mode and the whole vehicle state of the vehicle;
the switching period of the first voltage sampling mode is greater than that of the second voltage sampling mode, and the switching period of the second voltage sampling mode is greater than that of the third voltage sampling mode.
That is, the first voltage sampling mode is a slow voltage sampling mode and is suitable for a charging mode and a high-speed dynamic mode of the whole vehicle; at the moment, the sampling voltage is stable, and the calculation precision is highest; correspondingly, the second voltage sampling mode is a self-adaptive voltage sampling mode and is suitable for a static non-charging mode and a low-speed mode after the whole vehicle is electrified at high voltage; at the moment, the sampling voltage is relatively stable, and the calculation precision is high; the third voltage sampling mode is a rapid voltage sampling mode and is used for detecting the whole vehicle insulation resistance of the vehicle when only the main negative relay Kn is closed before the whole vehicle is electrified; at the moment, because a high-voltage circuit of the vehicle is not switched on and voltage fluctuation does not exist, the insulation resistance of the whole vehicle can be detected by using the rapid voltage sampling mode, but the calculation accuracy is low. According to one embodiment of the invention, the calculated value of the insulation resistance ranges from 0 Mohm to 4Mohm, and the switching period of the first voltage sampling mode can be set to be more than 10 s; the switching period of the second voltage sampling mode is not lower than the time T that the voltage is stable and can be sampled (namely, delta U/delta T < deltaU 2/delta T, and delta U2 is a calibration value); the switching period of the third voltage sampling mode may be set within 1 s.
In more detail, because the reporting period of the traditional bridge method insulation detection is as long as 1 min-3 min, the traditional bridge method cannot monitor the insulation resistance before the vehicle is electrified due to the consideration of customer experience and the fast electrification requirement of the whole vehicle. The insulation detection method provided by the embodiment of the invention can carry out active insulation quick reporting and monitor the insulation resistance of the whole vehicle, thereby realizing insulation monitoring before the whole vehicle is electrified, and the specific control strategy is as follows:
firstly, canceling the waiting time based on circuit response, and directly sampling the voltage; before the whole vehicle is electrified, the main negative relay Kn is closed, and the main positive relay (Kp) is in an off state, so that insulation detection is carried out;
secondly, when the sampling voltage change rate of delta U/delta T is smaller than a calibration value, directly sampling voltage data; as shown in FIG. 5, the sampling is started when the delta U1/delta T >. DELTA.U 2/delta T and the delta U/delta T <. DELTA.U 2/delta T; wherein, Δ U2 is used to represent the steady value of the sampling voltage waveform, and can be set to a calibrated value, i.e. the sampling voltage is less than U2 to start sampling;
it can be understood that the included angle of the slope in fig. 5 can represent the size of Δ U/Δ T, that is, the smaller the included angle, the more stable the voltage is, the sampling requirement is satisfied; the larger the included angle is, the faster the voltage change is, and the sampling is not facilitated.
And finally, calculating the insulation resistance of the high-voltage bus to the ground according to the voltage data sampling result.
Since the shorter the switching period of the insulation detection relay, i.e., the faster the switching frequency of the first relay S1 and the second relay S2, the sharper the peak value of the sampled voltage, the worse the voltage accuracy; on the contrary, the slower the switching frequency of the first relay S1 and the second relay S2 is, the more stable the sampling voltage is; the switching frequency of the first relay S1 and the second relay S2 can be set to be about 1 second, so that the whole sampling period can be completed within 5 seconds and the insulation resistance of the whole vehicle can be reported, the speed is high, and customer complaints can be avoided.
In addition, as shown in fig. 8, under a dynamic working condition, if a rapid acceleration working condition occurs, the bus voltage may jump rapidly to cause fluctuation, so that the insulation detection precision is affected, and false alarm may be caused; at this time, in order to increase the sampling voltage precision, the vehicle can be controlled to enter a slow voltage sampling mode, that is, the switching period is increased from 1s to 5-10 s (or other calibration values over 10 s), so that the accuracy of insulation detection is ensured.
Optionally, the calculating the insulation resistance of the high-voltage bus to ground according to the voltage data includes:
when the first voltage is greater than the second voltage, according to the first voltage, the second voltage, the third voltage and the first resistor R0Calculating the resistance value of a second insulation resistor Rn in the insulation resistors of the high-voltage bus to the ground according to a first functional relation; otherwise, according to the first voltage, the second voltage, the fourth voltage and the second resistor R0' calculating the resistance value of a first insulation resistor Rp in the high-voltage bus to ground insulation resistors;
wherein the first resistor R0In parallel with the first insulation resistance Rp, the second resistance R0' in parallel with the second insulation resistance Rn.
In the insulation detection method provided in an embodiment of the present invention, a sampling voltage waveform is calculated based on insulation with a self-adaptive function, and a sampling timing sequence of the method is different from that of insulation detection by a conventional bridge method, as shown in fig. 4:
the insulation detection method needs to acquire 4 voltage values which are respectively a first voltage V1, a second voltage V2, a third voltage V1Ln and a fourth voltage V2 Ln; the first voltage V1 and the third voltage V1Ln respectively represent the positive pole ground sampling voltage of the power supply under different conditions, and the second voltage V2 and the fourth voltage V2Ln respectively represent the negative pole ground sampling voltage of the power supply under different conditions; here, the different conditions refer to different open and close states of the first relay S1 and the second relay S2.
Specifically, the sampling timing sequence of the insulation detection method is as follows:
firstly, simultaneously closing a first relay S1 and a second relay S2, and acquiring a first voltage V1 and a second voltage V2 after a first preset time;
secondly, the second relay S2 is turned off, and after a second preset time, a third voltage V1Ln is acquired;
thirdly, the second relay S2 is closed and the first relay S1 is opened, and after a second preset time, a fourth voltage V2Ln is collected;
finally, comparing the magnitude relationship of the first voltage V1 and the second voltage V2:
if the first voltage V1 is greater than the second voltage V2, it indicates that the resistance of the first insulation resistor Rp is greater than the resistance of the second insulation resistor Rn; if the second voltage V2 is greater than the first voltage V1, it indicates that the resistance of the second insulation resistor Rn is greater than the resistance of the first insulation resistor Rp.
It is understood that the insulation performance of the vehicle is determined by the smaller of the two resistances of the high-voltage bus bar insulation resistance to ground, so when calculating the high-voltage bus bar insulation resistance to ground from the collected voltage data, we can calculate only the smaller one of the first insulation resistance (Rp) and the second insulation resistance (Rn); that is, when the first voltage is greater than the second voltage, the resistance of the second insulation resistor Rn of the high-voltage bus-to-ground insulation resistors may be calculated according to a first functional relationship among the first voltage, the second voltage, and the third voltage calculation:
the first function relationship is:
otherwise, the resistance value of the first insulation resistor Rp in the high-voltage bus-to-ground insulation resistors can be calculated according to a second functional relationship among the first voltage, the second voltage and the fourth voltage:
the second function relationship is as follows:
wherein Rn represents a resistance value of the second insulation resistor Rn; rp represents the resistance value of the first insulation resistor Rp; r0Represents a first resistance R0The resistance value of (1); r0' denotes a second resistance R0' resistance value; v1Representing a first voltage; v2Representing a second voltage; v1lnRepresents a third voltage; v2lnRepresenting a fourth voltage.
As can be seen from the above, once complete voltage data sampling can be completed after each one of the first preset time and the two second preset times; that is, the sampling period is the sum of the first preset time and the two second preset times.
Optionally, the insulation detection method further includes:
reporting the resistance values of the first insulation resistor Rp and the second insulation resistor Rn every preset reporting period;
the preset reporting period is an integral multiple of the sum of the first preset time and the two second preset times.
It should be noted that the preset reporting period (i.e., the reporting period of the insulation resistance of the vehicle) may be calculated by N sampling periods and then output, where N is a calibration value; that is to say, the first preset time and the second preset time may be set according to a specific vehicle in a calibration manner, or may be set according to a specific situation, after how many sampling periods pass, perform insulation calculation according to sampled voltage data, and report the insulation resistance of the entire vehicle (that is, the resistance values of the first insulation resistance Rp and the second insulation resistance Rn).
Through the reporting period of the insulation resistance of different layers, insulation misinformation can be prevented.
Optionally, the insulation detection method further includes:
and adjusting the preset reporting period according to the resistance values of the first insulation resistor Rp and the second insulation resistor Rn.
Optionally, the adjusting the preset reporting period according to the resistance values of the first insulation resistor Rp and the second insulation resistor Rn includes:
when the resistance value of any one of the first insulation resistor Rp and the second insulation resistor Rn is less than or equal to a first preset resistance value, adjusting the preset reporting period to be a first reporting period;
when the resistance values of the first insulation resistor Rp and the second insulation resistor Rn are both larger than the first preset resistance value, adjusting the preset reporting period to be a second reporting period;
wherein the first reporting period is less than the second reporting period.
It can be understood that if any one of the first insulation resistor Rp and the second insulation resistor Rn detected and calculated is small, the risk of the vehicle having an insulation fault is large, and the preset reporting period may be adjusted to a short time interval; when the first insulation resistance Rp and the second insulation resistance Rn are both large, the risk of insulation failure of the vehicle in a short period is small, so that the preset reporting period can be adjusted to a long time interval; the first preset resistance value, the first reporting period and the second reporting period can be calibrated according to specific conditions of the vehicle. According to an embodiment of the present invention, the first preset resistance may be set to 500ohm/V, the first reporting period may be set to 30s, and the second reporting period may be set to 1 min.
By the method, aiming at the condition that the insulation fault is easy to occur in the dynamic driving and charging process to cause customer complaints, the strategy of increasing the switching period of the insulation detection relay or adjusting the insulation resistance reporting period (namely the preset reporting period) of the vehicle is adopted, so that the stability of the sampled voltage data can be improved, and the generation of false reports is prevented.
In addition, the insulation detection method provided in one embodiment of the present invention may also be configured to prompt the user that the insulation aging phenomenon occurs in the battery pack of the vehicle when the resistance value of any one of the first insulation resistor Rp and the second insulation resistor Rn is smaller than the insulation aging threshold value, for monitoring the insulation aging intermediate state; the insulation aging threshold is a calibrated value, such as 1150 Kohm.
Optionally, the insulation detection method further includes:
monitoring the voltage variation amplitude of the bus, and stopping reporting the resistance values of the first insulation resistor Rp and the second insulation resistor Rn when the voltage variation amplitude of the bus is larger than a voltage threshold value.
That is to say, the peak voltage can be filtered through voltage filtering, and when the bus voltage variation amplitude is too large, the insulation function detection is not performed, and the reporting is stopped.
Optionally, the insulation detection method further includes:
and reporting an insulation fault when the resistance value of any one of the first insulation resistor Rp and the second insulation resistor Rn is smaller than a second preset resistance value.
It should be noted that the vehicle charging or the high voltage supply may be prohibited in the failure mode.
It should be noted that, if the vehicle detects an insulation fault before being powered on, the user may be prompted to manually repeat powering on and powering off for several times to try to eliminate the fault; and if the fault cannot be eliminated after the attempt and lasts for more than 5 minutes, reporting the insulation fault and prompting a user that the vehicle needs to be maintained.
The flow of the insulation control method is shown in fig. 9, and the vehicle switches three insulation control strategies (i.e. a fast voltage sampling mode, a slow voltage sampling mode and a self-adaptive voltage sampling mode) according to different vehicle working conditions (such as a power-on working condition, a charging working condition, a static and low speed working condition, a high speed dynamic working condition and the like); the insulation control method is tested in a real vehicle at present, can take the advantages of insulation detection by a passive bridge method and an active signal method into consideration, and has the stability of the bridge method and the rapidity of the active insulation detection method.
As shown in fig. 9, a flowchart of an insulation detection method according to an embodiment of the present invention is shown:
s901: starting;
s902: when the main and negative relays Kn are powered on and closed on the whole vehicle, S903 is executed;
s903: controlling the vehicle to enter a rapid voltage sampling mode (namely a third voltage sampling mode), and calculating the resistance value of the first insulation resistor Rp or the second insulation resistor Rn by collecting voltage data;
s904: judging whether an insulation fault exists according to the calculation result in the S903; if yes, executing S905; otherwise, executing S906;
s905: reporting the insulation fault, and prompting a client to try to power on again to remove the fault;
s906: after the main positive relay Kp is closed, the whole vehicle is electrified, and S907 is executed;
s907: reading a vehicle finishing mode of a vehicle; when the vehicle mode is the driving mode, executing S908; when the vehicle-finishing mode is the charging mode, executing S911;
s908: when the whole vehicle mode is a driving mode, judging whether the vehicle speed is greater than a preset speed or the acceleration is greater than a preset acceleration; if yes, go to S909; otherwise, go to S910;
s909: controlling the vehicle to enter a slow voltage sampling mode (namely a first voltage sampling mode), and calculating the resistance value of the first insulation resistor Rp or the second insulation resistor Rn by collecting voltage data;
s910: controlling the vehicle to enter a self-adaptive voltage sampling mode (namely a second voltage sampling mode), and calculating the resistance value of the first insulation resistor Rp or the second insulation resistor Rn by collecting voltage data;
s911: when the vehicle-finishing mode is the charging mode, the main positive relay Kp is disconnected, and S909 is executed;
s912: judging whether an insulation fault exists; if yes, go to S913; otherwise, executing S907;
s913: and reporting the insulation fault.
In the embodiment of the invention, different voltage sampling strategies are adopted aiming at different scenes of the vehicle, so that the insulation fault can be reported quickly; the anti-interference capability of the vehicle insulation detection function is enhanced, the accuracy of the whole vehicle insulation resistance calculation is improved, the reporting time is short, the false alarm can be prevented, and the customer experience is improved.
As shown in fig. 10, an embodiment of the present invention further provides an insulation detection apparatus applied to an insulation detection circuit of a vehicle, the insulation detection circuit including a main positive relay Kp, a main negative relay Kn, and a high-voltage bus ground insulation resistor connected to a power supply of the vehicle, and further including an insulation detection relay and a voltage dividing resistor for insulation detection, the insulation detection apparatus including:
the mode selection module 101 is used for controlling the vehicle to enter a corresponding sampling mode according to the working condition of the vehicle; wherein, the working conditions are different, and the corresponding sampling modes are different;
the control processing module 102 is configured to control the insulation detection relay to be periodically turned on and off according to the sampling mode, and acquire voltage data; wherein the voltage data comprises a power supply positive electrode ground sampling voltage and a power supply negative electrode ground sampling voltage;
and the insulation calculation module 103 is used for calculating the insulation resistance of the high-voltage bus to the ground according to the voltage data.
It should be noted that the main positive relay Kp and the main negative relay Kn are respectively a positive relay and a negative relay of the vehicle power battery system, and both of them act according to the power-on sequence requirement of the entire vehicle. The embodiment of the invention adopts different sampling modes according to different working conditions of the vehicle, so that the whole vehicle insulation resistance (namely the ground insulation resistance of the high-voltage bus) of the vehicle can be calculated more timely and accurately.
Optionally, the mode selection module 101 includes:
the first control submodule is used for controlling the vehicle to enter a first voltage sampling mode if the speed of the vehicle is higher than a preset speed or the acceleration is higher than a preset acceleration when the whole vehicle mode is a driving mode; otherwise, controlling the vehicle to enter a second voltage sampling mode;
and the second control submodule is used for controlling the vehicle to enter a first voltage sampling mode when the whole vehicle mode is a charging mode, the main negative relay Kn is closed and the main positive relay Kp is disconnected.
It should be noted that after the main positive relay Kp is closed, the whole vehicle is powered on; at the moment, according to the whole vehicle mode and the whole vehicle state of the vehicle, the mode of controlling the vehicle to enter is selected.
Optionally, the control processing module 102 includes:
a third control sub-module for controlling the first relay S1 and the second relay S2 of the insulation detection relays to be closed;
a first processing submodule for collecting a first resistor R in the voltage dividing resistor after the first relay S1 and the second relay S2 are closed for a first preset time0The voltage of the voltage divider is used as a first voltage, and a second resistor R in the voltage divider resistor is acquired0' as a second voltage and controls the second relay S2 to open;
a second processing submodule for acquiring the first resistance R after the second relay S2 is switched off for a second preset time0As a third voltage and controls the second relay S2 to close and the first relay S1 to open;
a third processing submodule for collecting the second resistance R after the second relay S2 is closed and the first relay S1 is opened for the second preset time0' as a fourth voltage;
a fourth control submodule for repeatedly executing the above steps;
the sum of the first preset time and the second preset time is the switching period of the insulation detection relay, and the switching periods of different sampling modes are different.
Optionally, the mode selection module 101 includes:
the fifth control submodule is used for controlling the vehicle to enter a third voltage sampling mode when the main and negative relays Kn are powered on and closed on the whole vehicle;
the sixth control submodule is used for completing the electrification of the whole vehicle after the main positive relay Kp is closed, and controlling the vehicle to enter the first voltage sampling mode or the second voltage sampling mode according to the whole vehicle mode and the whole vehicle state of the vehicle;
the switching period of the first voltage sampling mode is greater than that of the second voltage sampling mode, and the switching period of the second voltage sampling mode is greater than that of the third voltage sampling mode.
Optionally, the insulation calculation module 103 includes:
an insulation calculation submodule, configured to calculate the insulation value according to the first voltage, the second voltage, the third voltage, and the first resistor R when the first voltage is greater than the second voltage0Calculating the resistance value of a second insulation resistor Rn in the insulation resistors of the high-voltage bus to the ground according to a first functional relation; otherwise, according to the first voltage, the second voltage, the fourth voltage and the second resistor R0' calculating a first insulation resistance in the insulation resistance of the high-voltage bus to groundResistance of the Rp resistance;
wherein the first resistor R0In parallel with the first insulation resistance Rp, the second resistance R0' in parallel with the second insulation resistance Rn.
It is understood that the insulation performance of the vehicle is determined by the smaller of the two resistances of the high-voltage bus bar insulation resistance to ground, so when calculating the high-voltage bus bar insulation resistance to ground from the collected voltage data, we can calculate only the smaller one of the first insulation resistance (Rp) and the second insulation resistance (Rn); that is, when the first voltage is greater than the second voltage, the resistance of the second insulation resistor Rn of the high-voltage bus-to-ground insulation resistors may be calculated according to a first functional relationship among the first voltage, the second voltage, and the third voltage calculation:
the first function relationship is:
otherwise, the resistance value of the first insulation resistor Rp in the high-voltage bus-to-ground insulation resistors can be calculated according to a second functional relationship among the first voltage, the second voltage and the fourth voltage:
the second function relationship is as follows:
wherein Rn represents a resistance value of the second insulation resistor Rn; rp represents the resistance value of the first insulation resistor Rp; r0Represents a first resistance R0The resistance value of (1); r0' denotes a second resistance R0' resistance value; v1Representing a first voltage; v2Representing a second voltage; v1lnRepresents a third voltage; v2lnRepresenting a fourth voltage.
As can be seen from the above, once complete voltage data sampling can be completed after each one of the first preset time and the two second preset times; that is, the sampling period is the sum of the first preset time and the two second preset times.
Optionally, the insulation detecting device further includes:
the insulation reporting module is used for reporting the resistance values of the first insulation resistor Rp and the second insulation resistor Rn every preset reporting period;
the preset reporting period is an integral multiple of the sum of the first preset time and the two second preset times.
It should be noted that the preset reporting period (i.e., the reporting period of the insulation resistance of the vehicle) may be calculated by N sampling periods and then output, where N is a calibration value; that is to say, the first preset time and the second preset time may be set according to a specific vehicle in a calibration manner, or may be set according to a specific situation, after how many sampling periods pass, perform insulation calculation according to sampled voltage data, and report the insulation resistance of the entire vehicle (that is, the resistance values of the first insulation resistance Rp and the second insulation resistance Rn).
Through the reporting period of the insulation resistance of different layers, insulation misinformation can be prevented.
Optionally, the insulation detecting device further includes:
and the period adjusting module is used for adjusting the preset reporting period according to the resistance values of the first insulation resistor Rp and the second insulation resistor Rn.
Optionally, the period adjusting module includes:
a first adjusting submodule, configured to adjust the preset reporting period to a first reporting period when a resistance value of any one of the first insulation resistor Rp and the second insulation resistor Rn is less than or equal to a first preset resistance value;
a second adjusting submodule, configured to adjust the preset reporting period to a second reporting period when the resistance values of the first insulation resistor Rp and the second insulation resistor Rn are both greater than the first preset resistance value;
wherein the first reporting period is less than the second reporting period.
It can be understood that if any one of the first insulation resistor Rp and the second insulation resistor Rn detected and calculated is small, the risk of the vehicle having an insulation fault is large, and the preset reporting period may be adjusted to a short time interval; when the first insulation resistance Rp and the second insulation resistance Rn are both large, the risk of insulation failure of the vehicle in a short period is small, so that the preset reporting period can be adjusted to a long time interval; the first preset resistance value, the first reporting period and the second reporting period can be calibrated according to specific conditions of the vehicle. According to an embodiment of the present invention, the first preset resistance may be set to 500ohm/V, the first reporting period may be set to 30s, and the second reporting period may be set to 1 min.
Optionally, the insulation detecting device further includes:
and the voltage monitoring module is used for monitoring the voltage variation amplitude of the bus and stopping reporting the resistance values of the first insulation resistor Rp and the second insulation resistor Rn when the voltage variation amplitude of the bus is larger than a voltage threshold value.
That is to say, the peak voltage can be filtered through voltage filtering, and when the bus voltage variation amplitude is too large, the insulation function detection is not performed, and the reporting is stopped.
Optionally, the insulation detecting device further includes:
and the fault reporting module is used for reporting the insulation fault when the resistance value of any one of the first insulation resistor Rp and the second insulation resistor Rn is smaller than a second preset resistance value.
It should be noted that the vehicle charging or the high voltage supply may be prohibited in the failure mode.
It should be noted that, if the vehicle detects an insulation fault before being powered on, the user may be prompted to manually repeat powering on and powering off for several times to try to eliminate the fault; and if the fault cannot be eliminated after the attempt and lasts for more than 5 minutes, reporting the insulation fault and prompting a user that the vehicle needs to be maintained.
In the embodiment of the invention, different voltage sampling strategies are adopted aiming at different scenes of the vehicle, so that the insulation fault can be reported quickly; the anti-interference capability of the vehicle insulation detection function is enhanced, the accuracy of the whole vehicle insulation resistance calculation is improved, the reporting time is short, the false alarm can be prevented, and the customer experience is improved.
The embodiment of the invention also provides control equipment, which comprises a memory, a processor and a program which is stored on the memory and can be operated on the processor; the processor implements the insulation detection method as described above when executing the program.
The embodiment of the invention also provides an automobile which comprises the insulation detection device.
While the preferred embodiments of the present invention have been described, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.
Claims (13)
1. An insulation detection method applied to an insulation detection circuit of a vehicle, the insulation detection circuit including a main positive relay (Kp), a main negative relay (Kn) and a high-voltage bus insulation resistance to ground connected to a power supply of the vehicle, and further including an insulation detection relay and a voltage dividing resistance for insulation detection, the insulation detection method comprising:
controlling the vehicle to enter a corresponding sampling mode according to the working condition of the vehicle; wherein, the working conditions are different, and the corresponding sampling modes are different;
controlling the insulation detection relay to be periodically switched on and off according to the sampling mode, and collecting voltage data; wherein the voltage data comprises a power supply positive electrode ground sampling voltage and a power supply negative electrode ground sampling voltage;
and calculating the insulation resistance of the high-voltage bus to the ground according to the voltage data.
2. The insulation detection method according to claim 1, wherein the controlling the vehicle to enter the corresponding sampling mode according to the working condition of the vehicle comprises:
when the whole vehicle mode is a driving mode, if the speed of the vehicle is greater than a preset speed or the acceleration is greater than a preset acceleration, controlling the vehicle to enter a first voltage sampling mode; otherwise, controlling the vehicle to enter a second voltage sampling mode;
and when the whole vehicle mode is a charging mode, the main negative relay (Kn) is closed and the main positive relay (Kp) is disconnected, controlling the vehicle to enter a first voltage sampling mode.
3. The insulation detection method of claim 1, wherein said controlling the insulation detection relay to periodically close and open according to the sampling pattern and collecting voltage data comprises:
controlling a first relay (S1) and a second relay (S2) of the insulation detection relays to be closed;
acquiring a first resistance (R) of the voltage dividing resistances after the first relay (S1) and the second relay (S2) are closed for a first preset time0) As a first voltage, a second resistor (R) of the voltage dividing resistors is acquired0') as a second voltage and controls the second relay (S2) to open;
-acquiring said first resistance (R) after a second preset time of opening of said second relay (S2)0) As a third voltage, and controls the second relay (S2) to close and the first relay (S1) to open;
acquiring the second resistance (R) after the second relay (S2) is closed and the first relay (S1) is opened for the second preset time0') as a fourth voltage;
repeatedly executing the steps;
the sum of the first preset time and the second preset time is the switching period of the insulation detection relay, and the switching periods of different sampling modes are different.
4. The insulation detection method according to claim 3, wherein the controlling the vehicle to enter the corresponding sampling mode according to the working condition of the vehicle comprises:
when a main negative relay (Kn) is powered on and closed on the whole vehicle, controlling the vehicle to enter a third voltage sampling mode;
after a main positive relay (Kp) is closed, the whole vehicle is electrified, and the vehicle is controlled to enter a first voltage sampling mode or a second voltage sampling mode according to the whole vehicle mode and the whole vehicle state of the vehicle;
the switching period of the first voltage sampling mode is greater than that of the second voltage sampling mode, and the switching period of the second voltage sampling mode is greater than that of the third voltage sampling mode.
5. The insulation detection method of claim 3, wherein said calculating the insulation resistance of the high voltage bus to ground from the voltage data comprises:
when the first voltage is greater than the second voltage, according to the first voltage, the second voltage, the third voltage and the first resistance (R)0) Calculating the resistance value of a second insulation resistor (Rn) in the high-voltage bus to ground insulation resistors according to a first functional relation; otherwise, according to the first voltage, the second voltage, the fourth voltage and the second resistance (R)0') calculating a resistance value of a first insulation resistor (Rp) of said high voltage bus to ground insulation resistors;
wherein the first resistance (R)0) In parallel with the first insulation resistance (Rp), the second resistance (R)0') is connected in parallel with said second insulation resistance (Rn).
6. The insulation detection method according to claim 5, further comprising:
reporting the resistance values of the first insulation resistor (Rp) and the second insulation resistor (Rn) every other preset reporting period;
the preset reporting period is an integral multiple of the sum of the first preset time and the two second preset times.
7. The insulation detection method according to claim 6, further comprising:
and adjusting the preset reporting period according to the resistance values of the first insulation resistor (Rp) and the second insulation resistor (Rn).
8. The insulation detection method according to claim 7, wherein the adjusting the preset reporting period according to the resistance values of the first insulation resistor (Rp) and the second insulation resistor (Rn) comprises:
when the resistance value of any one of the first insulation resistor (Rp) and the second insulation resistor (Rn) is less than or equal to a first preset resistance value, adjusting the preset reporting period to be a first reporting period;
when the resistance values of the first insulation resistor (Rp) and the second insulation resistor (Rn) are both greater than the first preset resistance value, adjusting the preset reporting period to a second reporting period;
wherein the first reporting period is less than the second reporting period.
9. The insulation detection method according to claim 6, further comprising:
monitoring the voltage variation amplitude of the bus, and stopping reporting the resistance values of the first insulation resistor (Rp) and the second insulation resistor (Rn) when the voltage variation amplitude of the bus is larger than a voltage threshold.
10. The insulation detection method according to claim 6, further comprising:
and reporting an insulation fault when the resistance value of any one of the first insulation resistor (Rp) and the second insulation resistor (Rn) is smaller than a second preset resistance value.
11. An insulation detecting device applied to an insulation detecting circuit of a vehicle, the insulation detecting circuit including a main positive relay (Kp), a main negative relay (Kn) and a high-voltage bus insulation resistance to ground connected to a power source of the vehicle, and further including an insulation detecting relay and a voltage dividing resistance for insulation detection, the insulation detecting device comprising:
the mode selection module is used for controlling the vehicle to enter a corresponding sampling mode according to the working condition of the vehicle; wherein, the working conditions are different, and the corresponding sampling modes are different;
the control processing module is used for controlling the insulation detection relay to be periodically switched on and off according to the sampling mode and collecting voltage data; wherein the voltage data comprises a power supply positive electrode ground sampling voltage and a power supply negative electrode ground sampling voltage;
and the insulation calculation module is used for calculating the insulation resistance of the high-voltage bus to the ground according to the voltage data.
12. A control device comprising a memory, a processor, and a program stored on the memory and executable on the processor; characterized in that the processor implements the insulation detection method according to any one of claims 1 to 10 when executing the program.
13. An automobile, characterized by comprising the insulation detection device according to claim 11.
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