Insulation detection method, device and controller

Abstract

The present invention discloses an insulation detection method, device and controller, which can effectively improve the anti-interference ability of insulation detection and effectively avoid the problem of direct failure of insulation detection function. The method part includes: judging whether the detected circuit currently meets the insulation detection conditions; when the insulation detection conditions are met, performing a first insulation detection according to a specified detection frequency; when the first insulation detection is invalid, switching to other detection frequencies for a second insulation detection, wherein the first insulation detection and the second insulation detection are respectively detected on different insulation detection circuits.

Description

Technical Field

[0001] The present invention relates to the technical field of insulation detection, and in particular to an insulation detection method, device and controller. Background Art

[0002] In many application fields, for safety reasons, it is usually necessary to perform insulation testing on certain high-voltage circuits. In some application scenarios, insulation testing may be affected by external factors and become invalid, because the lack of insulation testing function will lead to some adverse effects. For example, in the automotive application field, when electric vehicles are driving or charging, the high-voltage circuits that need to be insulated may be interfered by the environment or charging piles, resulting in insulation detection voltage distortion and insulation detection invalidity. Electric vehicle insulation testing is part of the safety detection function, and the lack of safety detection function may cause electric vehicles to be unable to be used normally.

[0003] In traditional solutions, the insulation detection voltage is usually collected according to a fixed procedure to calculate the insulation resistance. It can be seen that when the voltage sampled by the insulation detection has an invalid value, the insulation resistance value is miscalculated or the insulation resistance value cannot be calculated, which will directly make the insulation detection function invalid. Summary of the invention

[0004] The present invention provides an insulation detection method, device and controller to solve the technical problem that the insulation detection function is easily directly invalidated in the traditional solution.

[0005] To solve the above problems, the following solutions are provided:

[0006] In a first aspect, an insulation detection method is provided, comprising:

[0007] Determine whether the detected circuit currently meets the insulation detection conditions;

[0008] When the insulation test conditions are met, the first insulation test is performed at the specified test frequency;

[0009] When the first insulation detection is invalid, the second insulation detection is performed by switching to other detection frequencies, wherein the first insulation detection and the second insulation detection are respectively performed on different insulation detection circuits.

[0010] In a possible implementation, after switching to another detection frequency to perform the second insulation detection, the method further includes:

[0011] When the second insulation detection is invalid, the insulation detection fault information is output;

[0012] When the second insulation detection is effective, the insulation status detection result is output, and when the insulation detection is performed next time, the process returns to the step of performing the first insulation detection.

[0013] In a possible implementation, the insulation detection circuit used in the method includes a first switch, a second switch, a first resistor, a second resistor, a third resistor and a fourth resistor, one end of the first switch is connected to the positive terminal of the detected circuit, and the other end is connected to the ground terminal, one end of the second switch is connected to the negative terminal of the detected circuit, and the other end is connected to the ground terminal, one end of the first resistor is connected to the positive terminal, and the other end is connected to one end of the second resistor, one end of the second resistor is connected to the ground terminal, one end of the third resistor is connected to the ground terminal, and the other end is connected to one end of the fourth resistor, and the other end of the fourth resistor is connected to the negative terminal;

[0014] Perform the first insulation test at the specified test frequency, including:

[0015] Disconnect the first switch and the second switch, wait for the voltage to stabilize for T1, and then read the current voltage V of the second resistor. P and the voltage V of the third resistor N ;

[0016] When V P Greater than or equal to V N When the voltage is stable for a period of time T2, the first switch is closed, and the voltage V' of the second resistor is read. P and the voltage V' of the third resistor N ;

[0017] When V P With V N , and V' P With V' N When both are effective values, then according to V P 、V N 、V' P 、V' N Determine the insulation resistance of the circuit being tested;

[0018] When V P With V N , and / or, V' P With V' N When an invalid value appears, it is determined that the current first insulation detection is invalid.

[0019] In a possible implementation, the current voltage V of the second resistor is read. P and the voltage V of the third resistor N Afterwards, the method further comprises:

[0020] When V P Less than V N When the voltage is stable for a period of time T2, the second switch is closed, and the voltage V' of the second resistor is read. P and the voltage V' of the third resistor N .

[0021] In a possible implementation, the method further includes:

[0022] When V P and V N When the sum of the two equals the voltage at the positive and negative ends of the detected circuit, V P With V N is a valid value;

[0023] When V' P and V' N The sum of the voltages between the positive and negative ends of the detected circuit is equal to the voltage between the positive and negative ends of the detected circuit, and V P Greater than V' P 、V N Greater than V' N When V' P With V' N is a valid value.

[0024] In a possible implementation, switching to another detection frequency to perform a second insulation detection includes:

[0025] Close the first switch and the second switch, wait for the voltage to stabilize for a period of time T'1, and then read the current voltage V of the second resistor. P’ and the voltage V of the third resistor N’ ;

[0026] When V P’ Greater than or equal to V N’ When the voltage is stable for a period of time T'2, the second switch is disconnected, and the voltage V' of the second resistor is read. P’ and the voltage V' of the third resistor N’ ;

[0027] When V P’ With V N’ , and V' P’ With V' N’ When both are effective values, then according to V P’ 、V N’ 、V' P’ 、V' N’ Determine the insulation resistance of the circuit being tested;

[0028] When V P’ With V N’ , and / or, V' P’ With V' N’ When an invalid value appears, it is determined that the current second insulation detection is invalid.

[0029] In a possible implementation, the current voltage V of the second resistor is read. P’ and the voltage V of the third resistor N’Afterwards, the method further comprises:

[0030] When V P’ Less than V N’ When the voltage is stable for a period of time T'2, the first switch is turned off, and the voltage V' of the second resistor is read. P’ and the voltage V' of the third resistor N’ .

[0031] In a possible implementation, the method further includes:

[0032] When V P’ and V N’ When the sum of the two equals the voltage at the positive and negative ends of the detected circuit, V P’ With V N’ is a valid value;

[0033] When V' P’ and V' N’ The sum of the voltages between the positive and negative ends of the detected circuit is equal to the voltage between the positive and negative ends of the detected circuit, and V P’ Greater than V' P’ 、V N’ Greater than V' N’ When V' P’ With V' N’ is a valid value.

[0034] In a second aspect, an insulation detection device is provided, comprising:

[0035] A judgment module is used to judge whether the detected circuit currently meets the insulation detection conditions;

[0036] The detection module is used to perform a first insulation detection according to a detection frequency when the insulation detection conditions are met; when the first insulation detection is invalid, switch to other detection frequencies to perform a second insulation detection.

[0037] In a third aspect, a controller includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above insulation detection method when executing the computer program.

[0038] In a fourth aspect, a computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above insulation detection method are implemented.

[0039] In the scheme implemented by the above-mentioned insulation detection method, device and controller, different insulation detection circuits are formed, and the detection frequencies corresponding to different insulation detection circuits are also different. Since the anti-interference of different detection circuits in actual applications is different, the use of intelligent control of insulation detection frequency conversion can effectively improve the anti-interference ability of insulation detection, effectively avoid the problem of direct failure of the insulation detection function, ensure the normal realization of the insulation detection function, and be beneficial to the normal operation of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0041] Figure 1 is a schematic diagram of a flow chart of an insulation detection method in one embodiment of the present invention;

[0042] Figure 2 and Figure 3 It is a structural schematic diagram of the connection between the insulation detection circuit provided by the present invention and the circuit to be detected;

[0043] Figure 4 is a schematic diagram of a first insulation detection process of an insulation detection method according to an embodiment of the present invention;

[0044] Figure 5 2 is a schematic diagram of a second insulation detection process of an insulation detection method according to an embodiment of the present invention;

[0045] Figure 6 is a structural schematic diagram of an insulation detection device in one embodiment of the present invention;

[0046] Figure 7 It is a structural schematic diagram of a controller in one embodiment of the present invention. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] The insulation detection method provided by the present invention can be applied to an insulation detection system, which includes a controller, a detected circuit and an insulation detection circuit, wherein the insulation detection circuit is connected to the detected circuit, and the insulation detection circuit is a circuit set for performing insulation detection on the detected circuit. The controller can control the relevant devices (such as relays) of the insulation detection circuit so that the insulation detection circuit forms different insulation detection circuits for subsequent different insulation detections. During the detection process, the collection of insulation detection voltage may also be involved. The corresponding insulation detection voltage can be read through a voltage acquisition device and fed back to the controller, and the controller determines the final insulation state detection result according to the insulation detection voltage. It should be noted that the specific form of the insulation detection circuit used in the present invention is not limited, as long as it is controlled by the controller and can be switched into different insulation detection circuits to the detected circuit, the present invention does not limit it.

[0049] It should also be noted that the insulation detection method provided by the present invention can be applied in a variety of application fields, such as the field of vehicle products. The insulation detection method can be applied to the insulation detection of automobiles, or it can also be applied to other electronic equipment and systems with high-voltage circuits. No specific limitation is made, and no examples are given one by one. Among them, when applied to the insulation detection of automobiles, the above-mentioned controller may refer to the vehicle electronic control unit (Electronic Control Unit, ECU), and the electronic control unit may be a whole vehicle controller or an independent controller used alone to implement the present invention. The present invention does not make specific limitations. For the convenience of description, the insulation detection in the automobile is taken as an example in the embodiment of the present invention to describe the insulation detection method provided by the present invention in detail. Below, it will be described in detail through specific embodiments.

[0050] See also Figure 1 As shown, Figure 1 A schematic flow chart of an insulation detection method provided by an embodiment of the present invention includes the following steps:

[0051] S10: Determine whether the detected circuit currently meets the insulation detection conditions.

[0052] Before the insulation test of automotive equipment, in order to improve the detection accuracy and safety, it is usually necessary to determine whether the detected circuit currently meets the insulation test conditions. Different equipment products may have different insulation test conditions, which can be configured according to application requirements. The present invention does not exemplify them one by one.

[0053] For ease of understanding and description, here we take the insulation resistance test of a car as an example. Before performing a connection test on the detected circuit of the car, it is necessary to determine whether the car confirmation controller is in a stable working state and whether the detected circuit of the insulation test is stable. When the controller is in a stable working state and the detected circuit is also stable, it can be determined that the detected circuit currently meets the insulation test conditions; conversely, if the controller is not in a stable working state and / or the detected circuit is not stable, it may cause deviations or errors in subsequent insulation tests, so it is considered that the detected circuit does not meet the insulation test conditions.

[0054] Among them, the stable working state of the controller can be determined by the controller's own parameters. Whether the detected circuit is stable can be determined by detecting the output voltage of the relevant detection points of the detected circuit and judging whether the voltage is abnormal. The details are not described here one by one.

[0055] S20: When the insulation detection condition is met, a first insulation detection is performed according to the detection frequency.

[0056] When the insulation detection conditions are met, insulation detection can be started. The embodiment of the present invention is different from the prior art in that the present invention sets two different insulation detection circuits. The different insulation detection circuits may include multiple, but at least two. First, insulation detection is performed on the first insulation detection circuit according to the set insulation detection frequency. For the sake of ease of description, this insulation detection process is called the first insulation detection.

[0057] Among them, the first insulation detection process will be performed on the first insulation detection circuit according to the set insulation detection frequency, specifically, according to the set insulation detection frequency, the insulation detection voltage sampling is performed on the first insulation detection circuit by controlling the voltage detection device, and the validity of the first insulation detection is confirmed by using the insulation detection voltage collected on the first insulation detection circuit. If the insulation detection voltage detected at this time is valid, the insulation resistance value can be directly calculated according to the insulation detection voltage value to determine the insulation state of the detected circuit.

[0058] It is also worth noting that if the first insulation detection process is effective, the first insulation detection will be used for insulation detection next time until the first insulation detection is invalid.

[0059] It should be noted that, during the insulation detection process, it is possible that the insulation detection voltage collected during the first insulation detection process may be affected by factors such as external environmental interference, resulting in an invalid value. At this time, the insulation state obtained based on the insulation detection voltage is naturally invalid and wrong. If the insulation detection voltage obtained by the first insulation detection is invalid, the first insulation detection is confirmed to be invalid, the current insulation detection voltage is cleared, and step S30 is executed.

[0060] S30: When the first insulation detection is invalid, switching to other detection frequencies to perform a second insulation detection, wherein the first insulation detection and the second insulation detection are respectively detected on different insulation detection circuits.

[0061] In this embodiment, when the first insulation detection is invalid, in order to avoid the insulation detection function being realized, thereby causing the normal use of other functions of the car, in the embodiment of the present invention, other detection frequencies will be switched to perform the second insulation detection, and the first insulation detection and the second insulation detection are respectively detected on different insulation detection circuits. That is to say, switching to other detection frequencies for the second insulation detection means that according to the detection frequency switched to a different one from the first insulation detection, the insulation detection voltage sampling is performed on the second insulation detection circuit by controlling the voltage detection device, the first insulation detection circuit and the second insulation detection circuit are different insulation detection circuits, and the insulation detection voltage collected on the second insulation detection circuit is used to confirm the validity of the second insulation detection, thereby judging the insulation state of the detected circuit, so that the insulation detection function is guaranteed to be realized normally.

[0062] It can be seen that the insulation detection method proposed in the embodiment of the present invention forms different insulation detection circuits, and the insulation detection frequencies corresponding to different insulation detection circuits are also different. Since the anti-interference of different detection circuits in actual applications is different, the use of intelligent control of insulation detection frequency conversion can effectively improve the anti-interference ability of insulation detection, effectively avoid the problem of direct failure of the insulation detection function, ensure the normal realization of the insulation detection function, and be beneficial to the normal operation of the automobile.

[0063] Wherein, as described above, after switching to other detection frequencies for the second insulation detection, the following steps are also included:

[0064] S40: When the second insulation detection is invalid, output insulation detection fault information.

[0065] S50: When the second insulation test is effective, the insulation status test result is output, and when the insulation test is performed next time, the process returns to the step of performing the first insulation test.

[0066] In this embodiment, when performing the second insulation detection, there are two situations, one is that the second insulation detection is invalid, and the other is that the second insulation detection is valid. When the second insulation detection is invalid, the insulation detection fault information is directly output, for example, a fault prompt is given, or a report is made. At this time, when the insulation detection is performed again, a fault occurs, which is most likely an insulation fault of the detected circuit. The insulation detection fault information is directly output, and the insulation detection process is terminated, thereby reducing the probability of finding problems caused by insulation problems. When the second insulation detection is valid, the insulation resistance of the detected circuit is calculated based on the insulation detection voltage obtained by the second insulation detection, thereby obtaining the insulation state of the detected circuit, and outputting the insulation state detection result. When the insulation detection is performed next time, the first insulation detection step is jumped back again.

[0067] It can be seen from this embodiment that during the insulation detection process, the first and second insulation detections can be cyclically repeated by switching the detection frequency according to the actual insulation detection situation, thereby effectively ensuring the normal implementation of the insulation detection function.

[0068] As mentioned above, the insulation detection circuit used in the insulation detection method of the present invention can have various forms, as long as it is transformed into different insulation detection circuits to perform the first insulation detection and the second insulation detection process. In this regard, in an embodiment of the present invention, a specific insulation detection circuit is provided. The insulation detection circuit is an insulation detection circuit based on a balanced-unbalanced bridge. Please refer to Figure 2 and Figure 3 As shown, Figure 2 and Figure 3 Two structural schematic diagrams of an insulation detection circuit adopted by the insulation detection method provided by the present invention, the insulation detection circuit specifically includes a first switch S1, a second switch S2, a first resistor R1, a second resistor R2, a third resistor R3 and a fourth resistor R4, one end of the first switch S1 is connected to the positive terminal of the detected circuit, the other end of the first switch S1 is connected to the ground terminal, one end of the second switch S2 is connected to the negative terminal of the detected circuit, the other end of the second switch S2 is connected to the ground terminal, one end of the first resistor R1 is connected to the positive terminal, the other end of the first resistor R1 is connected to one end of the second resistor R2, one end of the second resistor R2 is connected to the ground terminal, one end of the third resistor R3 is connected to the ground terminal, the other end of the third resistor R3 is connected to one end of the fourth resistor R4, and the other end of the fourth resistor R4 is connected to the negative terminal.

[0069] It should be noted that the detected circuit referred to in the embodiment of the present invention may refer to the power battery circuit in the car, or other high-voltage circuits in the car, which are not specifically limited here. Figure 2In the example, the power battery circuit is used for explanation, wherein the positive terminal of the detected circuit corresponds to the VBAT+ terminal of the power battery, the positive terminal of the detected circuit corresponds to the VBAT- terminal of the power battery, and the ground terminal of the detected circuit corresponds to the GND terminal of the power battery circuit. The insulation resistance between the VBAT+ terminal and the GND terminal is RP, and the insulation resistance between the VBAT- terminal and the GND terminal is RN.

[0070] It should be noted that in some embodiments, a resistor R0 is further connected between the first switch S1 and the ground terminal, and a resistor R0 is further connected between the second switch S2 and the ground terminal. Figure 2 Taking the insulation detection circuit as an example, the first insulation detection and the second insulation detection process of the embodiment of the present invention are described in detail.

[0071] See also Figure 4 As shown, in one embodiment, in step S20, that is, performing the first insulation detection according to the detection frequency, specifically includes the following steps:

[0072] S21: Disconnect the first switch S1 and the second switch S2, wait for the voltage to stabilize for a period of time T1, and then read the current voltage V of the second resistor. P and the voltage V of the third resistor N .

[0073] In step S21, when performing the first insulation test, the first switch S1 and the second switch S2 are first disconnected. Figure 2 or Figure 3 It can be clearly seen from the circuit structure that a balanced bridge is established at this time. In order to obtain an accurate insulation detection voltage, it is necessary to wait for the voltage to stabilize for a period of time T1, and then use the voltage detection device to collect the current voltage of the second resistor and the voltage of the third resistor. For the convenience of description, the current voltage of the second resistor R2 may be recorded as V P , the current voltage of the third resistor R3 is recorded as V N .

[0074] S22: Judge V P With V N The size relationship.

[0075] S23: When V P Greater than or equal to V N When the voltage is stable for a period of time T2, the first switch S1 is closed, and the voltage V' of the second resistor is read. P and the voltage V' of the third resistor N .

[0076] S24: When V P Less than V NWhen that is the case, close the second switch S2. After waiting for a voltage stabilization duration T2, read the current voltage V' of the second resistor. P and the voltage V' of the third resistor. N .

[0077] For steps S22 - S24, it can be understood that when the first switch S1 and the second switch S2 are opened and V P and V N are read, there are two cases. One case is that V P is greater than or equal to V N , and the other case is that V P is less than V N . The processing methods for the two cases are as follows:

[0078] When V P is greater than or equal to V N , it can be known that RP ≥ RN. Then close the first switch S1. At this time, the first switch S1 is closed, the second switch S2 is open, and the voltages of the current second resistor and third resistor are read through the voltage detection device, denoted as V' P and V' N .

[0079] When V P is less than V N , it can be known that RP < RN. Then close the second switch S2. At this time, the first switch S1 is open, the second switch S2 is closed. After waiting for a voltage stabilization duration T2, read the current voltage V' of the second resistor P and the voltage V' of the third resistor N .

[0080] It can be seen that when the first switch S1 is closed and the second switch S2 is open, or the first switch S1 is open and the second switch S2 is closed, a non - balanced Wheatstone bridge is established at this time. It should be noted that the above - mentioned detection process involves two time parameters, namely the voltage stabilization duration T1 and the voltage stabilization duration T2. The above - mentioned voltage stabilization duration T1 and voltage stabilization duration T2 are related to the insulation detection frequency set for the first insulation detection. It can be seen that the insulation detection period T = T1 + T2, and the insulation detection frequency f = 1 / T. Regarding the specific values of T1 and T2, the embodiments of the present invention do not make any limitations.

[0081] S25: Judge the validity of V P and V N , as well as V' P and V' N .

[0082] S26: When V P and V N , as well as V' P and V' NWhen both are effective values, then according to V P 、V N 、V' P 、V' N Determine the insulation resistance of the circuit being tested.

[0083] After the above steps S23 and S24, two sets of voltage data can be obtained, namely V P With V N , and V' P With V' N However, due to external factors, the voltage data measured above may be invalid. It is understandable that when V P With V N After that, according to the collection V P With V N The circuit structure relationship of the insulation detection circuit used can be seen that V P With V N The following relationship must be met:

[0084] V P +V N =V Batt ;

[0085] It can be seen that when V P and V N When the sum of the two equals the voltage at the positive and negative ends of the detected circuit, it is determined that V P With V N is the effective value. That is, V P With V N The validity of the error range should be V P +V N =V Batt , otherwise, judge V P With V N is an invalid value, where V Batt It is the voltage value between VBAT+ terminal and VBAT+ terminal.

[0086] Similarly, based on the collection V' P With V' N The circuit structure relationship of the insulation detection circuit used can be seen that V' P With V' N The following relationship must be satisfied:

[0087] V' P +V' N =V Batt ;

[0088] V P >V' P ;

[0089] VN <V' N ;

[0090] That is, when V' P and V' N The sum of the voltages between the positive and negative ends of the detected circuit is equal to the voltage between the positive and negative ends of the detected circuit, and V P Greater than V' P 、V N Less than V' N When V' P With V' N is a valid value, otherwise, V' P With V' N is an invalid value.

[0091] Among them, according to V P 、V N 、V' P 、V' N Determining the insulation resistance of the detected circuit depends on the specific insulation detection circuit. In this embodiment, based on the circuit structure relationship, it can be determined according to V P 、V N 、V' P 、V' N Determine the insulation resistance of the circuit being tested, as shown below:

[0092] V P / R' P =V N / R' N ;

[0093] V' P / (R' P / / R0)=V' N / R' N ;

[0094] V P +V N =V' P +V' N ;

[0095] Among them, R' P is the parallel value of RP and (R1+R2), R' N is the parallel value of RN and (R3+R4), and R' can be obtained by the above formula P = and R' N , and then the insulation resistance RP and RN of the positive and negative ends of the detected circuit to the ground are obtained, that is, the insulation state of the detected circuit can be determined.

[0096] When V P With V N , and / or V' PWith V' N When an invalid value appears, it is judged that the current first insulation detection is invalid, that is, when V P With V N When an invalid value appears, it can be judged that the first insulation test is invalid. P With V' N When an invalid value appears, it can also be judged that the first insulation test is invalid. P With V N , and V' P With V' N If both of them show invalid values, it is determined that the current first insulation detection is invalid. It should be noted here that, as an example, when V P With V N Then, we get V' P With V' N Before, if we judge V P With V N If an invalid value appears, it can be judged that the first insulation test is invalid, and there is no need to continue the subsequent test to obtain V' P With V' N The process of calculating the value can reduce unnecessary work, and the present invention is not limited to this.

[0097] S27: Turn off the first switch S1 or the second switch S2, and jump back to step S21.

[0098] In this embodiment, according to V P 、V N 、V' P 、V' N After determining the insulation resistance of the detected circuit, this round of calculation has ended, and the V' P With V' N The switch control mode is used to select the subsequent switch processing action for the next round of detection. For example, if V' is detected P With V' N When the first switch S1 is closed in step S23, the first switch S1 is opened in step S27. For example, if V' is detected P With V' N When it is detected by closing the second switch S2 in step S24, the second switch S2 will be opened in step S27. That is to say, the embodiment of the present invention will readjust the switch state so that both the first switch and the second switch are opened, so as to start a new round of first insulation detection process, which will not be repeated here.

[0099] It can be seen that in the above embodiment, a first insulation detection method based on a balanced bridge-unbalanced bridge detection circuit is specifically proposed, which increases the feasibility of the solution. However, it should be noted that the first insulation detection process can also be performed based on other insulation detection circuits. Specific examples are not given here one by one, but no specific limitation is made.

[0100] It should be noted that when the first insulation test is invalid, the insulation test frequency needs to be switched and the second insulation test is started, wherein the second insulation test is also based on Figure 2 Or the balanced bridge-unbalanced bridge insulation detection circuit shown in 3, but the insulation detection circuit used in the first insulation detection is different, and the detection frequency is also different. The second insulation detection process is described in detail below.

[0101] like Figure 5 As shown, in one embodiment, in step S30, that is, switching to other detection frequencies to perform a second insulation detection, specifically includes the following steps:

[0102] S31: Close the first switch and the second switch, wait for the voltage to stabilize for a period of time T'1, and then read the current voltage V of the second resistor. P’ and the voltage V of the third resistor N’ .

[0103] For step S31, when performing the second insulation test, the first switch S1 and the second switch S2 are first closed. Figure 2 or Figure 3 It can be clearly seen from the circuit structure that a balanced bridge is established at this time. In order to obtain an accurate insulation detection voltage, it is necessary to wait for the voltage to stabilize for a period of time T'1, and then use the voltage detection device to collect the current voltage of the second resistor and the voltage of the third resistor. For the convenience of description, the current voltage of the second resistor may be recorded as V P’ , the current voltage of the third resistor is recorded as V N’ .

[0104] S32: Determine V P’ With V N’ The size relationship.

[0105] S33: When V P’ Greater than or equal to V N’ When the voltage is stable for a period of time T'2, the second switch S2 is turned off, and the current voltage V' of the second resistor is read. P’ and the voltage V' of the third resistor N’ .

[0106] S34: When V P’ Less than V N’ When the voltage is stable for a period of time T'2, the first switch S1 is turned off, and the current voltage V' of the second resistor is read.P’ and the voltage V' of the third resistor N’ .

[0107] For steps S32 - S24, it can be understood that when the first switch S1 and the second switch S2 are closed and V P’ and V N’ are read, there are two cases. One case is that V P’ is greater than or equal to V N’ , and the other case is that V P’ is less than V N’ . The processing methods for the two cases are as follows:

[0108] When V P’ is greater than or equal to V N’ , it can be known that RP ≥ RN, then the second switch S2 is disconnected. At this time, the first switch S1 is closed and the second switch S2 is disconnected. After waiting for the voltage stabilization duration T'2, the voltages of the current second resistor and the third resistor are read through the voltage detection device, and are respectively denoted as V' P’ and V' N’ .

[0109] When V P’ is less than V N’ , it can be known that RP < RN, then the first switch S1 is disconnected. At this time, the first switch S1 is disconnected and the second switch S2 is closed. After waiting for the voltage stabilization duration T'2, the voltage V' P’ of the current second resistor and the voltage V' N’ of the third resistor are read.

[0110] It can be seen that when the first switch S1 is closed and the second switch S2 is disconnected, or the first switch S1 is disconnected and the second switch S2 is closed, a non - balanced bridge is established at this time. It should be noted that the above - mentioned detection process involves two time parameters, namely the voltage stabilization duration T'1 and the voltage stabilization duration T'2. The above - mentioned voltage stabilization duration T'1 and voltage stabilization duration T'2 are related to the insulation detection frequency set for the second insulation detection. It can be seen that the insulation detection period T' = T'1 + T'2, and the insulation detection frequency f' == 1 / T'. Regarding the specific T'1 and T'2, among them, the insulation detection frequency f' of the second insulation detection is different from the insulation detection frequency f of the first insulation detection, and the embodiments of the present invention do not make any restrictions.

[0111] S35: Judge the validity of V P’ and V N’ , as well as V' P’ and V' N’ .

[0112] S36: When V P’ and V N’ , as well as V'P’ With V' N’ When both are effective values, then according to V P’ 、V N’ 、V' P’ 、V' N’ Determine the insulation resistance of the circuit being tested.

[0113] After the above steps S33 and S34, two sets of voltage data can be obtained, namely V P’ With V N’ , and V' P’ With V' N’ However, due to external factors, the voltage data measured above may be invalid. It is understandable that when V P’ With V N’ After that, according to the collection V P’ With V N’ The circuit structure relationship of the insulation detection circuit used can be seen that V P’ With V N’ The following relationship must be met:

[0114] V P’ +V N’ =V Batt ;

[0115] It can be seen that when V P’ and V N’ When the sum of the voltages between the positive and negative ends of the detected circuit is equal to the voltage between the positive and negative ends of the detected circuit, it is determined that V P’ With V N’ is the effective value. That is, V P’ With V N’ The validity of the error range should be V P’ +V N’ =V Batt , otherwise, judge V P’ With V N’ is an invalid value.

[0116] Similarly, based on the collection V' P’ With V' N’ The circuit structure relationship of the insulation detection circuit used can be seen that V' P’ With V' N’ The following relationship must be satisfied:

[0117] V' P’ +V' N’ =V Batt ;

[0118] V P’ >V' P’ ;

[0119] VN’ <V' N’ ;

[0120] That is, when V' P’ and V' N’ The sum of the voltages between the positive and negative ends of the detected circuit is equal to the voltage between the positive and negative ends of the detected circuit, and V P’ Greater than V' P’ 、V N’ Less than V' N’ When V' P’ With V' N’ is a valid value, otherwise, V' P’ With V' N’ is an invalid value.

[0121] Among them, according to V P’ 、V N’ 、V' P’ 、V' N’ Determining the insulation resistance of the detected circuit depends on the specific insulation detection circuit. In this embodiment, based on the circuit structure relationship, it can be determined according to V P’ 、V N’ 、V' P’ 、V' N’ Determine the insulation resistance of the circuit being tested, as shown below:

[0122] V P’ / R' P =V N’ / R' N ;

[0123] V' P’ / (R' P / / R0)=V' N’ / R' N ;

[0124] V P’ +V N’ =V' P’ +V' N’ ;

[0125] Among them, R' P is the parallel value of RP and (R1+R2), R' N is the parallel value of RN and (R3+R4), and R' can be obtained by the above formula P = and R' N , and then the insulation resistance RP and RN of the positive and negative ends of the detected circuit to the ground are obtained, that is, the insulation state of the detected circuit can be determined.

[0126] When V P’ With V N’ , and / or V' P’With V' N’ When an invalid value appears, it is judged that the current second insulation detection is invalid. That is to say, when V P’ With V N’ If an invalid value appears, it can be judged that the second insulation test is invalid. P’ With V' N’ When an invalid value appears, the second insulation test can also be judged to be invalid. P’ With V N’ , and V' P’ With V' N’ If both of them show invalid values, it is determined that the second insulation test is invalid. It should be noted here that, as an example, when V P’ With V N’ Then, we get V' P’ With V' N’ Before, if we judge V P’ With V N’ If an invalid value appears, it can be judged that the second insulation test is invalid, and there is no need to continue the subsequent test to obtain V' P’ With V' N’ The process of calculating the value can reduce unnecessary work, and the present invention is not limited to this.

[0127] S37: Disconnect the first switch S1 or the second switch S2 and re-enter the first insulation detection process.

[0128] In this embodiment, according to V P’ 、V N’ 、V' P’ 、V' N’ After determining the insulation resistance of the detected circuit, this round of calculation has ended, and the V' P With V' N The switch control mode is used to select the subsequent switch processing action for the next round of detection. For example, if V' is detected P’ With V' N’ When the second switch S2 is disconnected as detected in step S33, the first switch S1 is disconnected in step S37. For example, if V' is detected P’ With V' N’ When it is detected that the first switch S1 is disconnected in step S34, the second switch S2 will be disconnected in step S37. That is to say, the embodiment of the present invention will readjust the switch state so that both the first switch and the second switch are disconnected, so as to enter the original first insulation detection process and start a new complete insulation detection process, which will not be repeated here.

[0129] It can be seen that in the above embodiment, a second insulation detection method based on a balanced bridge-unbalanced bridge detection circuit is specifically proposed, which increases the feasibility of the solution. However, it should be noted that the second insulation detection process can also be performed based on other insulation detection circuits. Specific examples are not given here one by one, but no specific limitation is made.

[0130] It is also worth noting that through the two specific embodiments of the above-mentioned first and second insulation detection processes, it can be clearly seen that in the embodiments of the present invention, different detection frequencies and insulation detection circuits are used in the first and second insulation detection processes, and different detection circuits correspond to different detection frequencies; different detection circuits have different anti-interference degrees, and intelligent control frequency conversion effectively improves the anti-interference ability of insulation detection.

[0131] It should also be noted that, when the first switch and the second switch are used, it can be realized by controlling a relay, and the present invention does not limit this.

[0132] It should be understood that the order of execution of the steps in the above embodiment does not necessarily mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention.

[0133] In one embodiment, an insulation detection device is provided, and the insulation detection device corresponds one-to-one with the insulation detection method in the above embodiment. Figure 6 As shown, the insulation detection device includes a judgment module 101 and a detection module 102. Each functional module is described in detail as follows:

[0134] The judging module 101 is used to judge whether the detected circuit currently meets the insulation detection conditions;

[0135] The detection module 102 is used to perform a first insulation detection at a detection frequency when the insulation detection condition is met; when the first insulation detection is invalid, switch to other detection frequencies to perform a second insulation detection.

[0136] In one embodiment, the detection module is further used for:

[0137] When the second insulation detection is invalid, outputting insulation detection fault information;

[0138] When the second insulation detection is effective, the insulation status detection result is output, and when the insulation detection is performed next time, the process returns to the step of performing the first insulation detection.

[0139] In one embodiment, the insulation detection circuit used includes a first switch, a second switch, a first resistor, a second resistor, a third resistor and a fourth resistor, one end of the first switch is connected to the positive terminal of the detected circuit, and the other end is connected to the ground terminal, one end of the second switch is connected to the negative terminal of the detected circuit, and the other end is connected to the ground terminal, one end of the first resistor is connected to the positive terminal, and the other end is connected to one end of the second resistor, one end of the second resistor is connected to the ground terminal, one end of the third resistor is connected to the ground terminal, and the other end is connected to one end of the fourth resistor, and the other end of the fourth resistor is connected to the negative terminal;

[0140] The detection module is specifically used for:

[0141] Disconnect the first switch and the second switch, wait for the voltage to stabilize for a period of time T1, and then read the current voltage V of the second resistor. P and the voltage V of the third resistor N ;

[0142] When the V P Greater than or equal to V N When the voltage is stable for a period of time T2, the first switch is closed, and the current voltage V' of the second resistor is read. P and the voltage V' of the third resistor N ;

[0143] When the V P With V N , and V' P With V' N are all effective values, then according to the V P 、V N 、V' P 、V' N Determining the insulation resistance of the detected circuit;

[0144] When the V P With V N , and / or, V' P With V' N When an invalid value appears, it is determined that the current first insulation detection is invalid.

[0145] In one embodiment, the detection module is further specifically used for:

[0146] When the V P Less than V N When the voltage is stable for a period of time T2, the second switch is closed, and the current voltage V' of the second resistor is read. P and the voltage V' of the third resistor N .

[0147] In one embodiment, the detection module is further specifically used for:

[0148] When the V P and V N When the sum of the voltages between the positive and negative ends of the detected circuit is equal to the voltage between the positive and negative ends of the detected circuit, it is determined that V P With V N is a valid value;

[0149] When the V' P and V' N The sum of the voltages between the positive and negative ends of the detected circuit is equal to the voltage between the positive and negative ends of the detected circuit, and the V P Greater than V' P 、V N Greater than V' N When V' P With V' N is a valid value.

[0150] In one embodiment, the process of the detection module performing the second insulation detection includes:

[0151] Close the first switch and the second switch, wait for the voltage to stabilize for a period of time T'1, and then read the current voltage V of the second resistor. P’ and the voltage V of the third resistor N’ ;

[0152] When the V P’ Greater than or equal to V N’ When the voltage is stable for a period of time T'2, the second switch is turned off, and the current voltage V' of the second resistor is read. P’ and the voltage V' of the third resistor N’ ;

[0153] When the V P’ With V N’ , and V' P’ With V' N’ are all effective values, then according to the V P’ 、V N’ 、V' P’ 、V' N’ Determining the insulation resistance of the detected circuit;

[0154] When the V P’ With V N’ , and / or, V' P’ With V' N’ When an invalid value appears, it is determined that the current second insulation detection is invalid.

[0155] In one embodiment, the detection module is further specifically used for:

[0156] When the VP’ Less than V N’ When the voltage is stable for a period of time T'2, the first switch is turned off, and the current voltage V' of the second resistor is read. P’ and the voltage V' of the third resistor N’ .

[0157] In one embodiment, the detection module is further specifically used for:

[0158] When the V P’ and V N’ When the sum of the voltages between the positive and negative ends of the detected circuit is equal to the voltage between the positive and negative ends of the detected circuit, it is determined that V P’ With V N’ is a valid value;

[0159] When the V' P’ and V' N’ The sum of the voltages between the positive and negative ends of the detected circuit is equal to the voltage between the positive and negative ends of the detected circuit, and the V P’ Greater than V' P’ 、V N’ Greater than V' N’ When V' P’ With V' N’ is a valid value.

[0160] It can be seen that the insulation detection device proposed in the embodiment of the present invention forms different insulation detection circuits, and the detection frequencies corresponding to different insulation detection circuits are also different. Since the anti-interference of different detection circuits in actual applications is different, the use of intelligent control of insulation detection frequency conversion can effectively improve the anti-interference ability of insulation detection, effectively avoid the problem of direct failure of the insulation detection function, ensure the normal realization of the insulation detection function, and be beneficial to the normal operation of the automobile.

[0161] The specific definition of the insulation detection device can be found in the definition of the insulation detection method above, which will not be repeated here. Each module in the above insulation detection can be implemented in whole or in part by software, hardware and a combination thereof. Each of the above modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the controller in the form of software, so that the processor can call and execute the operations corresponding to each of the above modules.

[0162] In one embodiment, a controller is provided, which may be a vehicle-mounted vehicle controller or a vehicle-mounted electronic control unit, and its internal structure diagram may be as follows: Figure 7As shown. The controller includes a processor, a memory and a network interface connected through a system bus. The processor of the controller is used to provide computing and control capabilities. The memory of the controller may include a storage medium and an internal memory. The storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the storage medium. The network interface of the controller is used to communicate with an external voltage detection device and the like through a network connection. When the computer program is executed by the processor, an insulation detection method is implemented.

[0163] In one embodiment, a controller is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the following steps when executing the computer program:

[0164] Determine whether the detected circuit currently meets the insulation detection conditions;

[0165] When the insulation detection condition is met, performing a first insulation detection according to the detection frequency;

[0166] When the first insulation detection is invalid, the second insulation detection is performed by switching to other detection frequencies, wherein the first insulation detection and the second insulation detection are respectively performed on different insulation detection circuits.

[0167] In one embodiment, a computer readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the following steps are implemented:

[0168] Determine whether the detected circuit currently meets the insulation detection conditions;

[0169] When the insulation detection condition is met, performing a first insulation detection according to the detection frequency;

[0170] When the first insulation detection is invalid, the second insulation detection is performed by switching to other detection frequencies, wherein the first insulation detection and the second insulation detection are respectively performed on different insulation detection circuits.

[0171] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0172] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0173] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. An insulation detection method, characterized in that: include: Determine whether the detected circuit currently meets the insulation detection conditions; When the insulation detection condition is met, performing a first insulation detection at a specified detection frequency; When the first insulation detection is invalid, the second insulation detection is performed by switching to other detection frequencies, wherein the first insulation detection and the second insulation detection are respectively detected on different insulation detection circuits; and the other detection frequency is different from the specified detection frequency.

2. The insulation detection method according to claim 1, characterized in that: After switching to other detection frequencies to perform a second insulation detection, the method further includes: When the second insulation detection is invalid, outputting insulation detection fault information; When the second insulation detection is effective, the insulation status detection result is output, and when the insulation detection is performed next time, the process returns to the step of performing the first insulation detection.

3. The insulation detection method according to claim 2, characterized in that: The insulation detection circuit adopted by the method includes a first switch, a second switch, a first resistor, a second resistor, a third resistor and a fourth resistor, wherein one end of the first switch is connected to the positive terminal of the detected circuit, and the other end is connected to the ground terminal, one end of the second switch is connected to the negative terminal of the detected circuit, and the other end is connected to the ground terminal, one end of the first resistor is connected to the positive terminal, and the other end is connected to one end of the second resistor, and the other end of the second resistor is connected to the ground terminal, one end of the third resistor is connected to the ground terminal, and the other end is connected to one end of the fourth resistor, and the other end of the fourth resistor is connected to the negative terminal; The first insulation test is performed according to the specified test frequency, comprising: Disconnect the first switch and the second switch, wait for the voltage to stabilize for a period of time T1, and then read the current voltage VP of the second resistor and the voltage VN of the third resistor; When the VP is greater than or equal to VN, the first switch is closed, and after waiting for the voltage to stabilize for a period of time T2, the current voltage V'P of the second resistor and the voltage V'N of the third resistor are read; When the VP and VN, as well as V'P and V'N are all valid values, the insulation resistance of the detected circuit is determined according to the VP, VN, V'P, and V'N; When the VP and VN, and / or the V'P and V'N show invalid values, it is determined that the first insulation detection is currently invalid.

4. The insulation detection method according to claim 3, characterized in that: After reading the current voltage VP of the second resistor and the voltage VN of the third resistor, the method further includes: When the VP is less than VN, the second switch is closed, and after waiting for the voltage to stabilize for a time period T2, the current voltage V'P of the second resistor and the voltage V'N of the third resistor are read.

5. The insulation detection method according to claim 3 or 4, characterized in that: The method further comprises: When the sum of the VP and VN is equal to the voltage at the positive and negative ends of the detected loop, it is determined that the VP and VN are effective values; When the sum of V'P and V'N is equal to the voltage at the positive and negative ends of the detected loop, and VP is greater than V'P and VN is greater than V'N, V'P and V'N are determined to be effective values.

6. The insulation detection method according to claim 3, characterized in that: The switching to other detection frequencies to perform the second insulation detection includes: The first switch and the second switch are closed, and after waiting for the voltage to stabilize for a period of time T'1, the current voltage V P' of the second resistor and the voltage V N' of the third resistor are read; When the V P' is greater than or equal to V N', the second switch is turned off, and after waiting for the voltage to stabilize for a period of time T'2, the current voltage V'P' of the second resistor and the voltage V'N' of the third resistor are read; When the VP' and VN', as well as V'P' and V'N' are all valid values, the insulation resistance of the detected circuit is determined according to the VP', VN', V'P', and V'N'; When the V P' and V N', and / or V'P' and V'N' show invalid values, it is determined that the current second insulation detection is invalid.

7. The insulation detection method according to claim 6, characterized in that: After reading the current voltage V P' of the second resistor and the voltage V N' of the third resistor, the method further includes: When the V P' is less than V N', the first switch is turned off, and after waiting for the voltage to stabilize for a time period T'2, the current voltage V'P' of the second resistor and the voltage V'N' of the third resistor are read.

8. The insulation detection method according to claim 6 or 7, characterized in that: The method further comprises: When the sum of the VP' and V N' is equal to the voltage at the positive and negative ends of the detected loop, it is determined that the VP' and V N' are effective values; When the sum of V'P' and V'N' is equal to the voltage at the positive and negative ends of the detected loop, and V P' is greater than V'P' and V N' is greater than V'N', V'P' and V'N' are determined to be valid values.

9. An insulation detection device, characterized in that: include: A judgment module is used to judge whether the detected circuit currently meets the insulation detection conditions; The detection module is used to perform a first insulation detection at a specified detection frequency when the insulation detection condition is met; when the first insulation detection is invalid, switch to other detection frequencies to perform a second insulation detection; wherein the first insulation detection and the second insulation detection are respectively detected on different insulation detection circuits; and the other detection frequency is a different detection frequency from the specified detection frequency.

10. A controller comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the insulation detection method according to any one of claims 1 to 8 are implemented.

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