Insulation resistance determination method and device and medium

Abstract

The invention discloses an insulation resistance determination method and device and a medium, and relates to the technical field of power electronics. Single-end sampling is adopted, and only one high-precision voltage sampling circuit is involved in the hardware level. State switching processing is carried out on the first switch and the second switch according to the current switch closing strategy to obtain a negative bus-to-ground voltage value of the current stage, a corresponding positive bus-to-ground voltage value is determined based on the negative bus-to-ground voltage value of the current stage, calculation is directly carried out based on the negative bus-to-ground voltage value, the hardware level design is simplified, and meanwhile the cost is reduced. The design threshold is reduced. And according to the negative bus-to-ground voltage value and the positive bus-to-ground voltage value, a current proportion equation of the current stage is determined, and the polling time of multi-round switching is shortened. The obtained proportional equation of the ground voltage value of the negative bus is combined with the previous proportional equation of the previous stage, a dynamic equation model is established, the real-time value of the ground insulation resistance of the positive and negative buses can be solved after each switching, and the dynamic and real-time performance of the detection process is realized.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and in particular to a method, apparatus, and dielectric for determining insulation resistance. Background Technology

[0002] In the unbalanced bridge insulation detection scheme, a dual-terminal voltage sampling mode is adopted, that is, the positive busbar-to-ground voltage and the negative busbar-to-ground voltage are detected simultaneously. Specifically, the initial voltages of the positive and negative busesbars to ground are collected separately. Then, after connecting a detection resistor between the positive busbar and ground, the voltage data after switching is collected. Then, the detection resistor is disconnected, and the insulation resistance of the positive busbar to ground is obtained by solving the equations of the two independent voltage data. After initialization, the voltage data after switching is collected again after connecting a detection resistor between the negative busbar and ground. Then, the detection resistor is disconnected, and the insulation resistance of the negative busbar to ground is obtained by solving the equations of the two independent voltage data. In this way, the insulation resistances of the positive and negative busesbars to ground are obtained through four stages (initialization stage, positive busbar-to-ground power acquisition stage, initialization stage, negative busbar-to-ground power acquisition stage).

[0003] The entire process involves multiple steps of resistor switching and simultaneous equation calculations. Each branch requires two switching of the detection resistor, which lengthens the power supply system's cycle time. Furthermore, the complex circuit structure of the dual-sampling module corresponding to the positive and negative bus voltages to ground increases the difficulty of printed circuit board (PCB) layout.

[0004] Therefore, how to shorten the cycle time while reducing the circuit structure load and layout difficulty is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this application is to provide a method, apparatus, and medium for determining insulation resistance, in order to solve the technical problems of extended power supply cycle and complex circuit structure of dual-terminal voltage sampling that increases layout difficulty.

[0006] To solve the above-mentioned technical problems, this application provides a method for determining insulation resistance, applied to an insulation resistance detection circuit; the insulation resistance detection circuit includes two detection branches connected in parallel; a first switch and a second switch of one detection branch are respectively located on both sides of a preset grounding point; the preset grounding points of the two detection branches are connected and connected to one end of a third switch; the other end of the third switch is grounded; the method includes:

[0007] Close the third switch and obtain the current closing switch strategy; wherein the current closing switch strategy is either the first closing switch strategy or the second closing switch strategy;

[0008] The negative bus voltage to ground value at the current stage is obtained by performing state switching processing on the first switch and the second switch according to the current closing switch strategy.

[0009] Based on the current negative busbar-to-ground voltage value, determine the corresponding positive busbar-to-ground voltage value, and determine the current proportional equation based on the negative busbar-to-ground voltage value and the positive busbar-to-ground voltage value;

[0010] Obtain the previous proportional equation of the previous stage of the current stage; and combine the current proportional equation and the previous proportional equation to determine the resistance value of the insulation resistance between the positive and negative busbars and ground; wherein the closing switch strategy of the previous stage is different from the closing switch strategy of the current stage; when the current stage is the first stage, the previous proportional equation of the previous stage is not obtained, and the next stage of the current stage is taken as the new current stage, returning to the step of closing the third switch.

[0011] On the one hand, the process of determining the first closed-switch strategy and the second closed-switch strategy includes:

[0012] A control strategy for the combination of the switch states of the first switch and the second switch is obtained in advance;

[0013] According to the control strategy for each switch state combination, the first switch and the second switch are respectively processed to obtain the corresponding negative bus voltage value to ground.

[0014] The corresponding positive bus voltage to ground value is determined based on the negative bus voltage to ground value of each of the aforementioned switch state combination control strategies.

[0015] The current proportional equation is determined based on the negative bus-to-ground voltage value and the positive bus-to-ground voltage value of each of the aforementioned switch state combination control strategies, so as to obtain the proportional parameters of each of the aforementioned switch state combination control strategies;

[0016] The maximum and minimum proportional parameters are obtained by filtering the proportional parameters of each of the switch state combination control strategies.

[0017] The control strategy combining the switching states corresponding to the maximum and minimum proportional parameters is used as the first closed-switch strategy and the second closed-switch strategy.

[0018] On the other hand, the first closed switch strategy is that the first switch is closed and the second switch is open; the first detection branch including the first switch and the second switch also includes a first resistor and a second resistor; another detection branch includes a third resistor, a fourth resistor, and a fifth resistor; the first end of the first resistor is connected to the first end of the third resistor, the second end of the first resistor is connected to the first end of the first switch, and the second end of the first switch and the first end of the second switch are both connected to the preset grounding point; the second end of the second switch is connected to the first end of the second resistor, and the second end of the second resistor is connected to the second end of the fifth resistor; the second end of the third resistor and the first end of the fourth resistor are both connected to the preset grounding point and to the first end of the third switch; the second end of the fourth resistor is connected to the first end of the fifth resistor; the current stage of the negative bus voltage to ground is obtained by performing state switching processing on the first switch and the second switch according to the current closed switch strategy, including:

[0019] The connection point between the fourth resistor and the fifth resistor is used as the sampling point;

[0020] The voltage value of the sampling point is obtained by testing tools.

[0021] Based on the connection relationship between the fourth resistor and the fifth resistor, and the voltage value at the sampling point, the voltage value of the first negative bus to ground under the first closed switch strategy is obtained;

[0022] Correspondingly, determining the corresponding positive busbar-to-ground voltage value based on the negative busbar-to-ground voltage value at the current stage includes:

[0023] Obtain the total bus voltage value;

[0024] The voltage value of the first positive busbar to ground is determined based on the total busbar voltage value and the voltage value of the first negative busbar to ground.

[0025] On the other hand, determining the current proportional equation based on the negative busbar-to-ground voltage value and the positive busbar-to-ground voltage value includes:

[0026] The first proportional parameter is determined based on the voltage values ​​of the first negative busbar to ground and the voltage values ​​of the first positive busbar to ground.

[0027] When the first switch is closed and the second switch is open, the first parallel topology is formed by the positive busbar insulation resistance to ground, the third resistor and the first resistor.

[0028] The first series topology is formed by the fourth resistor and the fifth resistor;

[0029] The second parallel topology is formed by the insulation resistance of the negative busbar to ground and the resistance of the first series topology;

[0030] The current proportional equation is constructed based on the first proportional parameter, the resistance values ​​on the first parallel topology, and the second parallel topology.

[0031] On the other hand, the second closed switch strategy is that the first switch is open and the second switch is closed; the first detection branch including the first switch and the second switch also includes a first resistor and a second resistor; another detection branch includes a third resistor, a fourth resistor, and a fifth resistor; the first end of the first resistor is connected to the first end of the third resistor, the second end of the first resistor is connected to the first end of the first switch, and the second end of the first switch and the first end of the second switch are both connected to the preset grounding point; the second end of the second switch is connected to the first end of the second resistor, and the second end of the second resistor is connected to the second end of the fifth resistor; the second end of the third resistor and the first end of the fourth resistor are both connected to the preset grounding point and to the first end of the third switch; the second end of the fourth resistor is connected to the first end of the fifth resistor; the current proportional equation is determined based on the negative bus voltage to ground value and the positive bus voltage to ground value, including:

[0032] The second proportional parameter is determined based on the second negative bus voltage to ground value and the second positive bus voltage to ground value under the second closed switch strategy;

[0033] When the first switch is open and the second switch is open, the third parallel topology is formed by the insulation resistance of the positive busbar to ground and the third resistor.

[0034] The first series topology is formed by the fourth resistor and the fifth resistor;

[0035] The fourth parallel topology is formed by the insulation resistance of the negative busbar to ground, the resistance of the first series topology, and the second resistance.

[0036] The current proportional equation is constructed based on the second proportional parameter, the resistance values ​​on the third parallel topology, and the fourth parallel topology.

[0037] On the other hand, after the negative busbar-to-ground voltage value of the current stage is determined, before determining the corresponding positive busbar-to-ground voltage value based on the negative busbar-to-ground voltage value of the current stage, the method further includes:

[0038] Obtain the first preset negative bus voltage value to ground at the current preset acquisition time and the second preset negative bus voltage value to ground at the previous preset acquisition time;

[0039] The first difference is determined based on the first preset negative busbar voltage to ground value and the second preset negative busbar voltage to ground value;

[0040] If the first difference does not exceed the first threshold, the insulation resistance detection circuit is determined to have reached a stable state, so as to proceed to the step of determining the corresponding positive busbar to ground voltage value based on the negative busbar to ground voltage value of the current stage.

[0041] On the other hand, after the negative busbar-to-ground voltage value of the current stage is determined, before determining the corresponding positive busbar-to-ground voltage value based on the negative busbar-to-ground voltage value of the current stage, the method further includes:

[0042] Obtain the current negative busbar-to-ground voltage value as the third preset negative busbar-to-ground voltage value;

[0043] Obtain the fourth preset negative busbar to ground voltage value after filtering the third preset negative busbar to ground voltage value;

[0044] The second difference is determined based on the third preset negative busbar voltage to ground value and the fourth preset negative busbar voltage to ground value;

[0045] If the second difference does not exceed the second threshold and is maintained for a preset time, it is determined that the insulation resistance detection circuit has reached a stable state, so as to proceed to the step of determining the corresponding positive busbar to ground voltage value based on the negative busbar to ground voltage value of the current stage.

[0046] On the other hand, after the negative busbar-to-ground voltage value of the current stage is determined, before determining the corresponding positive busbar-to-ground voltage value based on the negative busbar-to-ground voltage value of the current stage, the method further includes:

[0047] Acquire the ground voltage values ​​of each preset negative busbar and each preset positive busbar within a preset acquisition period;

[0048] Within each preset negative busbar to ground voltage value, the maximum preset negative busbar to ground voltage value and the minimum preset negative busbar to ground voltage value are selected, and a third difference value is determined based on the maximum preset negative busbar to ground voltage value and the minimum preset negative busbar to ground voltage value.

[0049] Within each preset positive busbar to ground voltage value, the maximum preset positive busbar to ground voltage value and the minimum preset positive busbar to ground voltage value are selected, and a fourth difference value is determined based on the maximum preset positive busbar to ground voltage value and the minimum preset positive busbar to ground voltage value.

[0050] If the third difference does not exceed the third threshold and the fourth difference does not exceed the fourth threshold, then the insulation resistance detection circuit is determined to have reached a stable state, so as to proceed to the step of determining the corresponding positive busbar to ground voltage value based on the negative busbar to ground voltage value of the current stage.

[0051] To address the aforementioned technical problems, this application also provides an apparatus for determining insulation resistance, comprising:

[0052] Memory, used to store computer programs;

[0053] A processor is configured to implement the steps of the method for determining the insulation resistance when executing the computer program.

[0054] To address the aforementioned technical problems, this application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the method for determining insulation resistance as described above.

[0055] This application provides a method for determining insulation resistance. First, the insulation resistance detection circuit includes two detection branches connected in parallel. In one detection branch, a first switch and a second switch are located on opposite sides of a preset grounding point. The preset grounding points of the two detection branches are connected, and one end of a third switch is also connected. The other end of the third switch is grounded. This application employs single-ended sampling, meaning that only one high-precision voltage sampling circuit is involved at the hardware level to transfer and collect the negative busbar-to-ground voltage. This facilitates the use of a closed-switch strategy to process the state switching of the first and second switches to obtain the negative busbar-to-ground voltage value. No additional hardware sampling circuit for the positive busbar-to-ground voltage value is required, reducing voltage sampling hardware by 50% compared to conventional solutions. This simplifies PCB layout and component selection, and also reduces hardware costs and failure rates. Secondly, the third switch is closed, and the current closing switch strategy corresponding to the first or second closing switch strategy is obtained. Based on the current closing switch strategy, the first and second switches are state-switched to obtain the negative bus-to-ground voltage value for the current stage. Regardless of whether it's the first or second closing switch strategy, the difference in circuit characteristics between the two strategies effectively improves the stability of the subsequent proportional equation solution, providing a reliable data foundation for insulation resistance calculation from a hardware perspective and ensuring detection accuracy. Thirdly, the corresponding positive bus-to-ground voltage value is determined based on the current negative bus-to-ground voltage value. Compared to conventional methods that collect positive bus-to-ground voltage, this application directly calculates it based on the negative bus-to-ground voltage value, simplifying hardware design and lowering the design threshold. The current proportional equation for the current stage is determined based on the negative and positive bus-to-ground voltage values, reducing the polling time for multiple switching rounds. Finally, the previous proportional equation of the previous stage is obtained. This previous proportional equation is obtained by combining the proportional equation of the negative busbar to ground voltage value collected after each detection resistance switch with the previous proportional equation obtained from the historical data of the previous stage to establish a dynamic equation model. After each switch, the real-time value of the positive and negative busbar to ground insulation resistance can be calculated. Except for the first switch action, after the switch state of the current stage is switched, the previous proportional equation corresponding to the data collected when the switch action of the previous stage is immediately called. By combining the proportional equations of two adjacent stages, it is not necessary to wait for the switch combination corresponding to all closed switch strategies to be completed, which significantly shortens the patrol cycle. This allows all results to be calculated as long as there is a closed switch strategy, ensuring that the positive and negative busbar insulation resistance is detected synchronously, realizing the dynamic and real-time detection process.

[0056] In addition, this application also provides an apparatus and medium for determining insulation resistance, which have the same beneficial effects as the above-described method for determining insulation resistance. Attached Figure Description

[0057] To more clearly illustrate the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0058] Figure 1 A flowchart illustrating a method for determining insulation resistance provided in an embodiment of this application;

[0059] Figure 2 This is a schematic diagram of an insulation resistance detection circuit provided in an embodiment of this application;

[0060] Figure 3 This is a schematic diagram of another insulation resistance detection circuit provided in an embodiment of this application;

[0061] Figure 4 A flowchart illustrating another method for determining insulation resistance provided in an embodiment of this application;

[0062] Figure 5 A structural diagram of an insulation resistance determination device provided in an embodiment of this application;

[0063] Figure 6 This is a structural diagram of an insulation resistance determination device provided in an embodiment of this application. Detailed Implementation

[0064] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this application.

[0065] The core of this application is to provide a method, apparatus, and medium for determining insulation resistance, in order to solve the technical problems of extended power supply system polling cycles and increased layout difficulty due to the complex circuit structure of dual-terminal voltage sampling.

[0066] To enable those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0067] In the practical application of current unbalanced bridge insulation detection schemes, the hardware design, detection logic, and capacitive load characteristics all play a role. Existing technologies generally employ a "dual-terminal voltage sampling" mode, simultaneously detecting both the positive bus voltage to ground and the negative bus voltage to ground. This mode places high demands on the hardware system: on the one hand, multiple independent voltage sampling modules are required to separately acquire the voltage signals from the positive and negative buses; on the other hand, due to the negative voltage characteristics of the negative bus, additional negative voltage conditioning circuits (such as level boosting and isolation amplification) are needed to ensure the accuracy and safety of the sampled signals. These dual requirements lead to a complex hardware circuit structure, increasing not only the difficulty of PCB layout but also the complexity of component selection, cost control, and subsequent maintenance.

[0068] Common insulation resistance testing methods require a multi-step resistance switching + simultaneous equation calculation process. The specific steps are: first, collect the initial voltage to ground of the positive and negative busbars; then, connect detection resistors sequentially between the positive busbar and ground, and between the negative busbar and ground, collecting voltage data after each switching, disconnecting the detection resistor after each switch; finally, solve for the insulation resistance to ground of the positive and negative busbars by solving simultaneous equations using multiple sets of voltage data. This logic has two major problems: Long polling time: Due to the influence of parasitic capacitance in the circuit, the capacitor needs to undergo a charging and discharging process after each detection resistor switch, resulting in a significant delay in voltage stabilization; furthermore, each branch requires two resistance switching operations, further lengthening the single polling cycle of the power supply system, making it difficult to meet real-time detection requirements. Risk of false detection / missed detection: To shorten the polling time, existing optimized schemes only calculate the insulation resistance value for the end of the busbar with the lower voltage to ground. However, the operating conditions of the vehicle's electrical system are complex (such as load switching, voltage fluctuations, and environmental interference), and the insulation resistance of the positive and negative busbars to ground is constantly changing dynamically. Calculating only one end can lead to the inability to detect insulation abnormalities at the other end in a timely manner, or cause false alarms due to deviations in data from one end, seriously affecting the reliability of detection. The insulation resistance determination method provided in this application can solve the above-mentioned technical problems.

[0069] Figure 1 A flowchart illustrating a method for determining insulation resistance provided in this application embodiment is shown below. Figure 1 As shown, this is applied to an insulation resistance detection circuit; the insulation resistance detection circuit includes two detection branches connected in parallel; the first and second switches of one detection branch are respectively located on both sides of a preset grounding point; the preset grounding points of the two detection branches are connected and connected to one end of a third switch; the other end of the third switch is grounded; the method includes:

[0070] S11: Close the third switch and obtain the current switch closing strategy;

[0071] The current closing switch strategy is either the first closing switch strategy or the second closing switch strategy;

[0072] S12: Based on the current closed switch strategy, perform state switching processing on the first switch and the second switch to obtain the negative bus voltage value at the current stage;

[0073] S13: Determine the corresponding positive busbar voltage value based on the current negative busbar voltage value, and determine the current proportional equation based on the negative busbar voltage value and the positive busbar voltage value;

[0074] S14: Obtain the previous proportional equation of the previous stage of the current stage; and combine the current proportional equation and the previous proportional equation to determine the resistance value of the insulation resistance between the positive and negative busbars and the ground.

[0075] The closing switch strategy in the previous stage is different from the closing switch strategy in the current stage. When the current stage is the first stage, the previous proportional equation of the previous stage is not obtained, and the next stage of the current stage is taken as the new current stage, returning to the step of closing the third switch.

[0076] Specifically, Figure 2 This is a schematic diagram of an insulation resistance detection circuit provided in an embodiment of this application, as shown below. Figure 2 As shown, it includes a first detection branch 1 and a second detection branch 2. The first switch K1 and the second switch K2 of the first detection branch 1 are located on both sides of a preset grounding point, and the preset grounding points of the first detection branch 1 and the second detection branch 2 are connected to each other and connected to one end of a third switch K3. The other end of the third switch K3 is grounded. Here, the grounding is the vehicle body ground that is finally connected to the preset grounding point.

[0077] Before closing the third switch in step S11, the system is powered on for calibration. After completing the initialization process, the total bus voltage is calibrated using voltage sampling data from the insulation detector to ensure the accuracy of the reference parameters. Closing the third switch then officially starts the insulation detection system, entering real-time detection mode.

[0078] To obtain the current closing switch strategy, it should be noted that the current closing switch strategy is either the first closing switch strategy or the second closing switch strategy. The two closing switch strategies are for the corresponding switching strategies in different stages, as long as the closing switch strategies corresponding to the two stages are different.

[0079] The control strategy for the combination of the switching states of the first and second switches is a combination strategy for the closing / opening of the first and second switches. There are four main types: First, both the first and second switches are closed; Second, the first switch is closed and the second switch is open; Third, the first switch is open and the second switch is closed; Fourth, both the first and second switches are open.

[0080] Taking the current closed-switch strategy as an example, the state switching process of the first and second switches is performed to obtain the negative bus-to-ground voltage value of the current stage. Here, the raw signal of the negative bus-to-ground voltage is collected, and then signal filtering can be performed to eliminate high-frequency noise interference. The filtered voltage signal can also be analyzed to confirm its stable state. After reaching a stable state, the voltage data under stable conditions needs to be recorded, and the process proceeds to step S13, where the corresponding positive bus-to-ground voltage value is determined based on the current negative bus-to-ground voltage value. This differs from the conventional acquisition process; in this application, the positive bus-to-ground voltage value is calculated based on the current negative bus-to-ground voltage value. Since the total bus voltage is known, the positive bus-to-ground voltage value can be derived from the total bus voltage and the negative bus-to-ground voltage value.

[0081] The current proportional equation is determined based on the voltage values ​​of the negative busbar to ground and the voltage values ​​of the positive busbar to ground. Different series and parallel topologies are obtained based on the opening and closing status of each switch under the closed switch strategy, and then the corresponding proportional equation is formed. For example, the proportional parameter is obtained by dividing the voltage values ​​of the negative busbar to ground and the voltage values ​​of the positive busbar to ground. This proportional parameter is also for the ratio between the insulation resistance of the positive and negative busbars to ground. However, in the series and parallel topology, the proportional equation needs to be constructed based on the resistance values ​​of the series or parallel resistors under the specific series and parallel topology.

[0082] In step S14, the previous proportional equation of the previous stage is obtained. By combining the current proportional equation and the previous proportional equation, the unknown parameter of the insulation resistance of the positive and negative busbars to ground can be obtained.

[0083] When the current stage is the initial stage, the previous proportional equation from the previous stage is not acquired, and the next stage is taken as the new current stage, returning to the step of closing the third switch. It should be noted that when the current stage is the initial stage, there is no previous stage, so it is not necessary to acquire the previous proportional equation. In this case, the next stage is taken as the new current stage, and the process returns to the step of closing the third switch to obtain the proportional equation for the new current stage. The initial simultaneous equation determination requires the acquisition of proportional equations from two different closing switch strategies. Subsequent simultaneous equation determinations can be achieved by combining the proportional equations acquired in the current stage and those acquired in the previous stage, obtaining the two resistance parameters—positive and negative busbar insulation resistance to ground—in one step.

[0084] For example: Step 1, system power-on calibration: After the equipment is powered on, the initialization process is completed. The voltage sampling data of the insulation tester is used to calibrate the total voltage of the bus to ensure the accuracy of the reference parameters.

[0085] Step 2, activate the detection function: Close K3 to officially start the insulation detection system and enter the real-time monitoring state.

[0086] Step 3, K1 closing sampling: Close switch K1 and open K2 to collect the original signal of the negative bus voltage to ground.

[0087] Step 4, signal filtering: Filter the acquired voltage signal to eliminate high-frequency noise interference.

[0088] Step 5, Steady-state assessment: Analyze the filtered voltage signal to confirm that it has reached a steady state.

[0089] Step 6, Generate Equation 1: Record the voltage data under steady-state conditions and construct the first voltage equation (Equation 1).

[0090] Step 7, switch to K2 closure: open K1, close K2, and collect the original signal of the negative bus voltage to ground.

[0091] Step 8, Filtering: Perform the same filtering process on the voltage signal acquired this time.

[0092] Step 9, Steady-state judgment: Verify the stability of the filtered voltage to ensure data validity.

[0093] Step 10, Solve the initial values ​​simultaneously: Based on the current stable data, generate Equation 2, and solve Equation 1 and Equation 2 simultaneously to calculate the insulation resistance (Rp) of the positive busbar to ground and the insulation resistance (Rn) of the negative busbar to ground for the first time.

[0094] Step 11, switch back to K1 closed: open K2, close K1, and collect the negative bus voltage to ground.

[0095] Step 12, Signal Processing: Repeated Filtering and Steady-State Judgment.

[0096] Step 13, Update the simultaneous equations: Update Equation 1 with the current stable data, and combine it with Equation 2 from the previous round to recalculate Rp and Rn.

[0097] Step 14: Switch back to K2 closing: Open K1, close K2, and collect the negative bus voltage to ground.

[0098] Step 15, Signal Processing: Repeated Filtering and Steady-State Judgment.

[0099] Step 16, Dynamically update the solution: Update equation 2 with the current stable data, combine it with the current equation 1, and recalculate Rp and Rn.

[0100] This application provides a method for determining insulation resistance. First, the insulation resistance detection circuit includes two detection branches connected in parallel. In one detection branch, a first switch and a second switch are located on opposite sides of a preset grounding point. The preset grounding points of the two detection branches are connected, and one end of a third switch is also connected. The other end of the third switch is grounded. This application employs single-ended sampling, meaning that only one high-precision voltage sampling circuit is involved at the hardware level to transfer and collect the negative bus voltage to ground. This facilitates the use of a closed-switch strategy to process the state switching of the first and second switches to obtain the negative bus voltage to ground value. No additional hardware sampling circuit for the positive bus voltage to ground value is required, reducing voltage sampling hardware by 50% compared to conventional solutions. This simplifies PCB layout and component selection, and also reduces hardware costs and failure rates. Secondly, the third switch is closed, and the current closing switch strategy corresponding to the first or second closing switch strategy is obtained. Based on the current closing switch strategy, the first and second switches are state-switched to obtain the negative bus-to-ground voltage value for the current stage. Regardless of whether it's the first or second closing switch strategy, the difference in circuit characteristics between the two strategies effectively improves the stability of the subsequent proportional equation solution, providing a reliable data foundation for insulation resistance calculation from a hardware perspective and ensuring detection accuracy. Thirdly, the corresponding positive bus-to-ground voltage value is determined based on the current negative bus-to-ground voltage value. Compared to conventional methods that collect positive bus-to-ground voltage, this application directly calculates it based on the negative bus-to-ground voltage value, simplifying hardware design and lowering the design threshold. The current proportional equation for the current stage is determined based on the negative and positive bus-to-ground voltage values, reducing the polling time for multiple switching rounds. Finally, the previous proportional equation of the previous stage is obtained. This previous proportional equation is obtained by combining the proportional equation of the negative busbar to ground voltage value collected after each detection resistance switch with the previous proportional equation obtained from the historical data of the previous stage to establish a dynamic equation model. After each switch, the real-time value of the positive and negative busbar to ground insulation resistance can be calculated. Except for the first switch action, after the switch state of the current stage is switched, the previous proportional equation corresponding to the data collected when the switch action of the previous stage is immediately called. By combining the proportional equations of two adjacent stages, it is not necessary to wait for the switch combination corresponding to all closed switch strategies to be completed, which significantly shortens the patrol cycle. This allows all results to be calculated as long as there is a closed switch strategy, ensuring that the positive and negative busbar insulation resistance is detected synchronously, realizing the dynamic and real-time detection process.

[0101] In some embodiments, the process of determining the first closed-switch strategy and the second closed-switch strategy includes:

[0102] A control strategy for pre-acquiring the switching states of the first and second switches;

[0103] According to the control strategy for each switch state combination, the first switch and the second switch are switched to obtain the corresponding negative bus voltage to ground value.

[0104] The corresponding positive bus voltage to ground value is determined based on the negative bus voltage to ground value of each switch state combination control strategy.

[0105] The current proportional equation is determined based on the negative bus-to-ground voltage and positive bus-to-ground voltage values ​​of each switch state combination control strategy, so as to obtain the proportional parameters of each switch state combination control strategy.

[0106] The maximum and minimum proportional parameters are obtained by filtering the proportional parameters of each switch state combination control strategy;

[0107] The control strategy combining the switching states corresponding to the maximum and minimum proportional parameters is used as the first closed-switch strategy and the second closed-switch strategy.

[0108] Specifically, as mentioned in the above embodiments, there are four combinations of closing strategies for the first and second switches. The selection of these combinations depends on the different circuit characteristics under each closing strategy. Let the capacitance of the single-sided Y capacitor be C (unit: μF). Since a larger external insulation resistance results in a longer response time, we assume the insulation resistance to be infinite. The time constants for each state are calculated as follows:

[0109] 00 state (K1 and K2 are both disconnected): τ1=RC=6C;

[0110] State 01 (K1 open, K2 closed): τ2 = RC = 1.5C;

[0111] 10 states (K1 closed, K2 open): τ3 = RC = 1.5C;

[0112] 11 states (K1 and K2 are both closed): τ4 = RC = 0.4C.

[0113] To ensure the rapid response of the detection system, the 00 state is directly excluded.

[0114] In the process of solving the above simultaneous equations, calculations such as Vp1 / Vn1-Vp2 / Vn2 are often involved. Ensuring the detection accuracy of this measurement becomes a key issue. From the perspective of signal-to-noise ratio optimization, the difference between Vp / Vn should be increased under different switching closure strategies.

[0115] In other words, noise is superimposed on both the current stage and the previous stage. By subtracting the ratio of the current stage from the previous stage, and considering the noise issue, the larger the difference in the ratio parameter between the current stage and the previous stage, the better, thus minimizing the impact of noise on the process. The ratio parameters of each switch state combination control strategy are screened to obtain the maximum and minimum ratio parameters; the switch state combination control strategies corresponding to the maximum and minimum ratio parameters are used as the first closed-loop switch strategy and the second closed-loop switch strategy, respectively.

[0116] At this point, the first closed-switch strategy, where the first switch is closed and the second switch is open, and the second closed-switch strategy, where the first switch is open and the second switch is closed, are selected.

[0117] The screening and determination process for the first and second closed-loop switching strategies provided in this embodiment can maintain a reasonable voltage difference between the positive bus-to-ground voltage and the negative bus-to-ground voltage, avoiding amplification of calculation errors caused by excessively small voltage differences. The circuit characteristics under the first and second closed-loop switching strategies differ significantly, effectively improving the uniqueness and stability of the equation solution. This provides a reliable data foundation for insulation resistance calculation at the hardware level, directly ensuring detection accuracy.

[0118] In some embodiments, such as Figure 2 As shown, the first closed switch strategy is that the first switch K1 is closed and the second switch K2 is open; the first detection branch 1, which includes the first switch K1 and the second switch K2, also includes a first resistor R1 and a second resistor R2; another detection branch includes a third resistor R3, a fourth resistor R4, and a fifth resistor R5; the first end of the first resistor R1 is connected to the first end of the third resistor R3, and the second end of the first resistor R1 is connected to the first end of the first switch K1. The second ends of the first switch K1 and the first ends of the second switch K2 are both connected to a preset grounding point; the second end of the second switch K2 is connected to the first end of the second resistor R2, and the second end of the second resistor R2 is connected to the second end of the fifth resistor R5; the second ends of the third resistor R3 and the first ends of the fourth resistor R4 are both connected to a preset grounding point and to the first end of the third switch K3; the second end of the fourth resistor R4 is connected to the first end of the fifth resistor R5; the state switching process of the first switch K1 and the second switch K2 according to the current closed switch strategy is performed to obtain the negative bus voltage value of the current stage, including:

[0119] The connection point between the fourth resistor R4 and the fifth resistor R5 is used as the sampling point;

[0120] The voltage value of the sampling point is obtained by testing tools.

[0121] Based on the connection relationship between the fourth resistor R4 and the fifth resistor R5, and the voltage value at the sampling point, the voltage value of the first negative bus to ground under the first closed switch strategy is obtained.

[0122] Correspondingly, the corresponding positive busbar-to-ground voltage value is determined based on the current negative busbar-to-ground voltage value, including:

[0123] Obtain the total bus voltage value;

[0124] The voltage value of the first positive busbar to ground is determined based on the total busbar voltage value and the voltage value of the first negative busbar to ground.

[0125] Specifically, such as Figure 2 As shown, the negative bus voltage to ground is the voltage between the vehicle body ground and the negative bus. When the first switch is closed and the second switch is open, the connection point between the fourth resistor and the fifth resistor is sampled to obtain the sampling point voltage value V1. Based on the connection relationship between the fourth resistor and the fifth resistor and the sampling point voltage value, the first negative bus voltage to ground value (Vn1=V1*(R4+R5) / R5) is obtained.

[0126] The calculation process for the voltage value of the first positive busbar to ground is: Vp1 = Vbus - Vn1.

[0127] The hardware provided in this embodiment only requires one high-precision voltage sampling circuit to collect the negative bus voltage to ground value. The positive bus voltage to ground value is derived from the known parameters of the system, eliminating the need for an additional positive bus sampling circuit. This reduces the need for general voltage sampling hardware, eliminates the need for a dedicated negative voltage conditioning circuit, simplifies PCB layout and component selection, and reduces hardware costs and failure rates.

[0128] In some embodiments, determining the current proportional equation based on the negative busbar-to-ground voltage value and the positive busbar-to-ground voltage value includes:

[0129] The first proportional parameter is determined based on the voltage values ​​of the first negative busbar to ground and the voltage values ​​of the first positive busbar to ground.

[0130] With the first switch closed and the second switch open, the first parallel topology is formed by the positive busbar insulation resistance to ground, the third resistor, and the first resistor.

[0131] The first series topology is formed by the fourth resistor and the fifth resistor;

[0132] The second parallel topology is formed by the insulation resistance of the negative busbar to ground and the resistance of the first series topology;

[0133] The current proportional equation is constructed based on the first proportional parameter, the resistance values ​​on the first parallel topology, and the second parallel topology.

[0134] Specifically, based on the actual resistance values ​​obtained in the above embodiments, the first negative busbar-to-ground voltage value and the first positive busbar-to-ground voltage value are used to divide the first negative busbar-to-ground voltage value and the first positive busbar-to-ground voltage value to obtain the first proportional parameter. If the two unknown parameters, negative busbar-to-ground insulation resistance and positive busbar-to-ground insulation resistance, are to be obtained, one of the simultaneous equations (the current proportional equation) needs to be established.

[0135] like Figure 2 As shown, with the first switch closed and the second switch open, three branches are formed. The first branch is from Rp and Rn to Vbus, the second branch is from R1, R4, and R5, and the third branch is from R3, R4, and R5. With the vehicle body ground as the axis of symmetry, the insulation resistance Rp to ground of the positive busbar, the third resistance R3, and the first resistance R1 constitute the first parallel topology, i.e., Vp1 is Rp / / R3 / / R1. In the second parallel topology, Rn / / (R4+R5), meaning the first proportional parameter VA = Vp1 / Vn1 = (Rp / / R3 / / R1) / (Rn / / (R4+R5)).

[0136] The process of establishing the current proportional equation under the first closed-loop switching strategy provided in this embodiment calculates the positive bus voltage to ground value after each detection resistor switching action, and then constructs the current proportional equation so that the current proportional equation of the current stage and the proportional equation of the previous stage can be combined to construct a dynamic equation model and improve accuracy.

[0137] In some embodiments, such as Figure 2 As shown, the second closed switch strategy is that the first switch K1 is open and the second switch K2 is closed; the first detection branch, which includes the first switch K1 and the second switch K2, also includes the first resistor R1 and the second resistor R2; another detection branch includes the third resistor R3, the fourth resistor R4, and the fifth resistor R5; the first end of the first resistor R1 is connected to the first end of the third resistor R3, and the second end of the first resistor R1 is connected to the first end of the first switch K1; the second ends of the first switch K1 and the first ends of the second switch K2 are both connected to a preset grounding point; the second end of the second switch K2 is connected to the first end of the second resistor R2, and the second end of the second resistor R2 is connected to the second end of the fifth resistor R5; the second ends of the third resistor R3 and the first ends of the fourth resistor R4 are both connected to a preset grounding point and to the first end of the third switch K3; the second end of the fourth resistor R4 is connected to the first end of the fifth resistor R5; the current proportional equation is determined based on the negative bus voltage to ground and the positive bus voltage to ground, including:

[0138] The second proportional parameter is determined based on the second negative bus to ground voltage value and the second positive bus to ground voltage value under the second closed switch strategy;

[0139] With the first switch K1 open and the second switch K2 open, the third parallel topology is formed by the insulation resistance of the positive busbar to ground and the third resistor R3.

[0140] The first series topology is formed by the fourth resistor R4 and the fifth resistor R5;

[0141] The fourth parallel topology is formed by the insulation resistance of the negative busbar to ground, the resistance of the first series topology, and the second resistance R2.

[0142] The current proportional equation is constructed based on the resistance values ​​of the second proportional parameter, the third parallel topology, and the fourth parallel topology.

[0143] Similarly, referring to the above embodiments, the process for determining the voltage value of the second negative bus to ground is: Vn1 = V2 * (R4 + R5) / R5, where V2 is the voltage value of the sampling point corresponding to the second closed switch strategy. The process for determining the voltage value of the second positive bus to ground is: Vp2 = Vbus - Vn2.

[0144] The second proportional parameter is obtained by dividing the voltage values ​​of the second negative busbar to ground and the second positive busbar to ground. To obtain the two unknown parameters, the insulation resistance of the negative busbar to ground and the insulation resistance of the positive busbar to ground, one of the simultaneous equations (the current proportional equation) needs to be established.

[0145] like Figure 2 As shown, with the first switch open and the second switch closed, three branches are formed. The first branch is from Rp and Rn to Vbus, the second branch is from R3, R4, and R5, and the third branch is from R3 and R2. With the vehicle body ground as the axis of symmetry, the positive busbar-to-ground insulation resistance Rn and the third resistance R3 form the third parallel topology, i.e., Vp2 is Rp / / R3. The negative busbar-to-ground insulation resistance, the resistance of the first series topology, and the second resistance form the fourth parallel topology, Rn / / (R4+R5) / / R2. In other words, the first proportional parameter VB = Vp2 / Vn2 = (Rp / / R3) / (Rn / / (R4+R5) / / R2).

[0146] The process of establishing the current proportional equation under the second closed-loop switching strategy provided in this embodiment calculates the positive bus voltage to ground value after each detection resistor switching action, and then constructs the current proportional equation so that the current proportional equation of the current stage and the proportional equation of the previous stage can be combined to construct a dynamic equation model, which improves accuracy, flexibility and diversity.

[0147] If the current stage uses the proportional equation under the second closed-switch strategy, and the previous stage uses the proportional equation under the first closed-switch strategy, then by solving the two equations simultaneously, we obtain:

[0148] Rn=-((R4+R5)*(R1*R2*VA-R1*R2*VB)) / (R1*R2*VA+R1*R4*VA+R1*R5*VA-R1*R2*VB+R2*R4*VA*VB+R2*R5*VA*VB);

[0149] Rp=-(R1*R2*R3*VA-R1*R2*R3*VB) / (R1*R3+R1*R2*VA+R2*R3*VA-R1*R2*VB).

[0150] In the circuit, the Y capacitor (common-mode rejection capacitor) and parasitic capacitance together constitute a capacitive load. During the voltage sampling process of insulation detection, a significant charging delay phenomenon of the RC circuit (Resistor-Capacitor Circuit) will occur—the larger the capacitance value, the longer the delay time for charging and discharging to reach a steady state. This delay will cause a deviation between the sampled voltage data and the actual steady-state value. Since the core of the insulation detection algorithm is to calculate the insulation resistance based on the steady-state voltage, the deviation data will directly affect the calculation accuracy of the algorithm, placing stringent requirements on the algorithm's anti-delay capability and data correction logic. Existing conventional algorithms cannot completely offset this effect.

[0151] In some embodiments, after the negative busbar-to-ground voltage value of the current stage is determined, and before determining the corresponding positive busbar-to-ground voltage value based on the negative busbar-to-ground voltage value of the current stage, the method further includes:

[0152] Obtain the first preset negative bus voltage value to ground at the current preset acquisition time and the second preset negative bus voltage value to ground at the previous preset acquisition time;

[0153] The first difference is determined based on the first preset negative busbar voltage to ground value and the second preset negative busbar voltage to ground value;

[0154] If the first difference does not exceed the first threshold, the insulation resistance detection circuit is determined to have reached a stable state, so as to proceed to the step of determining the corresponding positive busbar to ground voltage value based on the negative busbar to ground voltage value at the current stage.

[0155] Specifically, considering the load mutation dimension, the preset negative bus voltage values ​​to ground at preset sampling times are obtained. It should be noted that the preset sampling times before and after are different from the sampling times of the current and previous stages in the above embodiments; they are sampling times independent of the stage. A first difference is determined by the first and second preset negative bus voltage values ​​to ground. If the first difference exceeds a first threshold, it is determined to be a load mutation, indicating that a stable state has not been reached. If the first difference does not exceed the first threshold, it is not a load mutation, indicating a stable state has been reached, and subsequent data are used for insulation resistance calculation.

[0156] The stable state provided in this embodiment is determined by the dimension of load mutation, which reflects the stability in actual use better than testing only the steady-state condition. It avoids failures caused by load fluctuations in actual operation. Based on the stable state data under load mutation, the response speed under dynamic load is faster and the fluctuation is smaller.

[0157] In other embodiments, after the negative busbar-to-ground voltage value of the current stage is determined, and before determining the corresponding positive busbar-to-ground voltage value based on the negative busbar-to-ground voltage value of the current stage, the method further includes:

[0158] Obtain the current negative busbar-to-ground voltage value as the third preset negative busbar-to-ground voltage value;

[0159] Obtain the fourth preset negative busbar to ground voltage value after filtering the third preset negative busbar to ground voltage value;

[0160] The second difference is determined based on the third preset negative busbar voltage to ground value and the fourth preset negative busbar voltage to ground value;

[0161] If the second difference does not exceed the second threshold and is maintained for a preset time, the insulation resistance detection circuit is determined to have reached a stable state, so as to proceed to the step of determining the corresponding positive busbar to ground voltage value based on the negative busbar to ground voltage value of the current stage.

[0162] Specifically, considering high-frequency jitter, the current negative bus voltage to ground is obtained as the third preset negative bus voltage to ground value. After filtering, a fourth preset negative bus voltage to ground value is obtained. A second difference is determined using the third and fourth preset negative bus voltage to ground values. If the second difference exceeds a second threshold and remains so for a certain period, it is considered load jitter. If the second difference does not exceed the second threshold and remains so for a certain period, it indicates that no load jitter has occurred, and a stable state has been reached. Subsequent data is then used for insulation resistance calculations.

[0163] The stable state provided in this embodiment is determined by high-frequency jitter, avoiding output distortion, oscillation, or runaway caused by high-frequency interference. This is more in line with actual application scenarios than testing only the DC steady-state condition. It can expose design defects that cannot be detected by conventional steady-state testing in advance, avoiding component overheating, lifespan degradation, or even burnout caused by high-frequency resonance during actual operation.

[0164] In other embodiments, after the negative busbar-to-ground voltage value of the current stage is determined, and before determining the corresponding positive busbar-to-ground voltage value based on the negative busbar-to-ground voltage value of the current stage, the method further includes:

[0165] Acquire the ground voltage values ​​of each preset negative busbar and each preset positive busbar within a preset acquisition period;

[0166] Within each preset negative busbar to ground voltage value, the maximum preset negative busbar to ground voltage value and the minimum preset negative busbar to ground voltage value are selected, and the third difference value is determined based on the maximum preset negative busbar to ground voltage value and the minimum preset negative busbar to ground voltage value.

[0167] Within each preset positive busbar to ground voltage value, the maximum preset positive busbar to ground voltage value and the minimum preset positive busbar to ground voltage value are selected, and the fourth difference value is determined based on the maximum preset positive busbar to ground voltage value and the minimum preset positive busbar to ground voltage value.

[0168] If the third difference does not exceed the third threshold and the fourth difference does not exceed the fourth threshold, then the insulation resistance detection circuit is determined to have reached a stable state, so as to proceed to the step of determining the corresponding positive busbar to ground voltage value based on the negative busbar to ground voltage value at the current stage.

[0169] Specifically, in the process of calculating the insulation resistance value, a higher accuracy can be obtained when charging and discharging are completed and the load is stable. Therefore, the state of charging and discharging being completed and the load being stable can be identified by the fluctuation of the voltage between the positive and negative busbars and ground.

[0170] By using a fixed period, i.e., a preset negative busbar-to-ground voltage value and a preset positive busbar-to-ground voltage value within a preset acquisition period, the maximum and minimum preset negative busbar-to-ground voltage values ​​are selected from the preset negative busbar-to-ground voltage values, and a third difference is determined based on these values. Similarly, the maximum and minimum preset positive busbar-to-ground voltage values ​​are selected from the preset positive busbar-to-ground voltage values, and a fourth difference is determined based on these values. If both the third and fourth differences do not exceed a third threshold, a stable state is considered reached. Subsequent data is then used for insulation resistance calculations.

[0171] The positive and negative bus voltage fluctuation identification provided in this embodiment can identify the state where charging and discharging are complete and the load is stable, effectively filtering out unsteady data during the RC delay process and significantly reducing the impact of parasitic capacitance. This enhances the system's adaptability to complex operating conditions and ensures that detection accuracy is maintained even in special scenarios such as load fluctuations.

[0172] Regarding the first, second, and third switches, they can be switching transistors. Figure 3 This is a schematic diagram of another insulation resistance detection circuit provided in an embodiment of this application, as shown below. Figure 3As shown, this method can reduce insulation testing time while completely detecting Rp and Rn, thereby improving the efficiency and completeness of insulation testing of the object under test. Data acquisition and equation solving are performed using two states: K1 closed + K2 open and K1 open + K2 closed. Except for the initial switch action, after each switch state switchover, the data collected during the previous switch action is immediately retrieved. By solving the data from two adjacent states, the insulation resistance (Rp) of the positive busbar to ground and the insulation resistance (Rn) of the negative busbar to ground can be calculated in real time without waiting for all switch combinations to complete, significantly shortening the cycle time. Calculation results are output for each switchover, realizing the dynamic and real-time nature of the testing process.

[0173] Figure 4 A flowchart of another method for determining insulation resistance provided in an embodiment of this application is shown below. Figure 4 As shown, it includes:

[0174] S21: Initialize variables and calculate bus voltage compensation;

[0175] S22: Initiate insulation detection and issue a command to close K3;

[0176] S23: Issue the instruction to close K1;

[0177] S24: Record data;

[0178] S25: Determine whether the stability determination is passed; if yes, proceed to step S26; otherwise, return to step S24.

[0179] S26: Issue the command K1 to open and K2 to close;

[0180] S27: Record data;

[0181] S28: Determine whether the stability test is passed; if yes, proceed to step S29; otherwise, return to step S27.

[0182] S30: Calculate Rp and Rn;

[0183] S31: Issue the command K1 to close and K2 to open;

[0184] S32: Record data;

[0185] S33: Determine whether the stability test is passed; if yes, proceed to step S34; otherwise, return to step S32.

[0186] S34: Calculate Rp and Rn, and return to step S26.

[0187] The above describes in detail the various embodiments corresponding to the method for determining insulation resistance. Based on this, this application also discloses an insulation resistance determination device corresponding to the above method, which is applied to an insulation resistance detection circuit. The insulation resistance detection circuit includes two detection branches connected in parallel. The first switch and the second switch of one of the detection branches are respectively located on both sides of a preset grounding point. The preset grounding points of the two detection branches are connected and connected to one end of a third switch. The other end of the third switch is grounded. Figure 5 This is a structural diagram of an insulation resistance determination device provided in an embodiment of this application. Figure 5 As shown, the equipment for determining insulation resistance includes:

[0188] The acquisition module 11 is used to close the third switch and acquire the current closing switch strategy; wherein the current closing switch strategy is either the first closing switch strategy or the second closing switch strategy.

[0189] Processing module 12 is used to perform state switching processing on the first switch and the second switch according to the current closing switch strategy to obtain the negative bus voltage value at the current stage;

[0190] The determination module 13 is used to determine the corresponding positive busbar to ground voltage value based on the negative busbar to ground voltage value at the current stage, and to determine the current proportional equation based on the negative busbar to ground voltage value and the positive busbar to ground voltage value;

[0191] Module 14 is used to obtain the previous proportional equation of the previous stage of the current stage; and to combine the current proportional equation and the previous proportional equation to determine the resistance value of the insulation resistance between the positive and negative busbars and the ground; wherein, the closing switch strategy of the previous stage is different from the closing switch strategy of the current stage; when the current stage is the first stage, the previous proportional equation of the previous stage is not obtained, and the next stage of the current stage is taken as the new current stage, returning to the step of closing the third switch.

[0192] Since the embodiments of the device part correspond to the embodiments described above, please refer to the embodiments of the method part for the description of the device part, and will not be repeated here.

[0193] For a description of the insulation resistance determination device provided in this application, please refer to the above method embodiments. This application will not repeat the description here, but it has the same beneficial effects as the above insulation resistance determination method.

[0194] Figure 6 A structural diagram of an insulation resistance determination device provided in an embodiment of this application is shown below. Figure 6 As shown, the device includes:

[0195] Memory 21 is used to store computer programs;

[0196] Processor 22 is used to implement the steps of a method for determining insulation resistance when executing a computer program.

[0197] The processor 22 may include one or more processing cores, such as a quad-core processor or an octa-core processor. The processor 22 may be implemented using at least one of the following hardware forms: Digital Signal Processor (DSP), Field-Programmable Gate Array (FPGA), or Programmable Logic Array (PLA). The processor 22 may also include a main processor and a coprocessor. The main processor, also known as the Central Processing Unit (CPU), is used to process data in the wake-up state; the coprocessor is a low-power processor used to process data in the standby state. In some embodiments, the processor 22 may integrate a Graphics Processing Unit (GPU), which is responsible for rendering and drawing the content to be displayed on the screen. In some embodiments, the processor 22 may also include an Artificial Intelligence (AI) processor, which handles computational operations related to machine learning.

[0198] The memory 21 may include one or more computer-readable storage media, which may be non-transitory. The memory 21 may also include high-speed random access memory and non-volatile memory, such as one or more disk storage devices or flash memory devices. In this embodiment, the memory 21 is used to store at least the following computer program 211, which, after being loaded and executed by the processor 22, is capable of implementing the relevant steps of the insulation resistance determination method disclosed in any of the foregoing embodiments. In addition, the resources stored in the memory 21 may also include an operating system 212 and data 213, etc., and the storage method may be temporary storage or permanent storage. The operating system 212 may include Windows, Unix, Linux, etc. The data 213 may include, but is not limited to, the data involved in the insulation resistance determination method, etc.

[0199] In some embodiments, the insulation resistance determination device may further include a display screen 23, an input / output interface 24, a communication interface 25, a power supply 26, and a communication bus 27.

[0200] Those skilled in the field can understand, Figure 6 The structure shown does not constitute a limitation on the means of determining insulation resistance and may include more or fewer components than shown.

[0201] The processor 22 implements the insulation resistance determination method provided in any of the above embodiments by calling instructions stored in the memory 21.

[0202] For a description of the insulation resistance determination device provided in this application, please refer to the above method embodiments. This application will not repeat the description here, but it has the same beneficial effects as the above insulation resistance determination method.

[0203] Furthermore, this application also provides a computer-readable storage medium storing a computer program, which, when executed by processor 22, implements the steps of the above-described method for determining insulation resistance.

[0204] It is understood that if the methods in the above embodiments are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and executes all or part of the steps of the methods in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0205] For a description of the computer-readable storage medium provided in this application, please refer to the above method embodiments. This application will not repeat the description here, but it has the same beneficial effects as the above method for determining insulation resistance.

[0206] The foregoing has provided a detailed description of the method, apparatus, and medium for determining insulation resistance provided in this application. The various embodiments in the specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section. It should be noted that those skilled in the art can make several improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of this application.

[0207] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

Claims

1. A method of determining an insulation resistance, characterized by, The application is applied to an insulation resistance detection circuit; the insulation resistance detection circuit comprises two detection branches in parallel; the first switch and the second switch of one of the two detection branches are respectively located on both sides of a preset grounding point; The preset grounding points of the two detection branches are connected and connected to one end of a third switch; the other end of the third switch is grounded; the method comprises: closing the third switch and obtaining a current closed switch strategy; wherein the current closed switch strategy is a first closed switch strategy or a second closed switch strategy; According to the current closed switch strategy, the state switching process of the first switch and the second switch is obtained to obtain the negative bus voltage value of the current stage; Based on the negative bus voltage value of the current stage, the corresponding positive bus voltage value is determined, and the current proportional equation is determined according to the negative bus voltage value and the positive bus voltage value; The last proportional equation of the last stage of the current stage is obtained; the current proportional equation and the last proportional equation are determined in parallel to determine the resistance value of the positive and negative bus grounding insulation resistance; wherein the closed switch strategy of the last stage is different from that of the current stage; when the current stage is the first stage, the last proportional equation of the last stage is not obtained, and the next stage of the current stage is taken as a new current stage, and the step of closing the third switch is returned.

2. The method of determining an insulation resistance according to claim 1, characterized by, The determination process of the first closed switch strategy and the second closed switch strategy comprises: obtaining the switch state combination control strategy of the first switch and the second switch in advance; According to each of the switch state combination control strategy, the state switching process of the first switch and the second switch is obtained to obtain the corresponding negative bus voltage value; Based on the negative bus voltage value of each of the switch state combination control strategy, the corresponding positive bus voltage value is determined; According to the negative bus voltage value and the positive bus voltage value of each of the switch state combination control strategy, the current proportional equation is determined to obtain the proportional parameter of each of the switch state combination control strategy; The proportional parameters of each of the switch state combination control strategy are screened to obtain the maximum proportional parameter and the minimum proportional parameter; The switch state combination control strategy corresponding to the maximum proportional parameter and the minimum proportional parameter is taken as the first closed switch strategy and the second closed switch strategy.

3. The method of determining an insulation resistance according to claim 2, characterized by, The first closing switch strategy is that the first switch is closed and the second switch is opened; the first detection branch comprising the first switch and the second switch further comprises a first resistor and a second resistor; another detection branch comprises a third resistor, a fourth resistor and a fifth resistor; a first end of the first resistor is connected with a first end of the third resistor, a second end of the first resistor is connected with a first end of the first switch, a second end of the first switch and a first end of the second switch are connected with the preset grounding point; a second end of the second switch is connected with a first end of the second resistor, a second end of the second resistor is connected with a second end of the fifth resistor; a second end of the third resistor and a first end of the fourth resistor are connected with the preset grounding point and a first end of the third switch; a second end of the fourth resistor is connected with a first end of the fifth resistor; According to the current closing switch strategy, the state switching processing of the first switch and the second switch is performed to obtain the negative bus-to-ground voltage value of the current stage, comprising: The connection point between the fourth resistor and the fifth resistor is taken as a sampling point; The sampling point voltage value of the sampling point is obtained by testing tools; According to the connection relationship between the fourth resistor and the fifth resistor and the sampling point voltage value, the first negative bus-to-ground voltage value under the first closing switch strategy is obtained; Correspondingly, based on the negative bus-to-ground voltage value of the current stage, the corresponding positive bus-to-ground voltage value is determined, comprising: The total bus voltage value is obtained; According to the total bus voltage value and the first negative bus-to-ground voltage value, the first positive bus-to-ground voltage value is determined.

4. The method of determining an insulation resistance according to claim 3, characterized by, According to the negative bus-to-ground voltage value and the positive bus-to-ground voltage value, the current proportional equation is determined, comprising: Based on the first negative bus-to-ground voltage value and the first positive bus-to-ground voltage value, the first proportional parameter is determined; In the case that the first switch is closed and the second switch is opened, the first parallel topology structure is composed of the positive bus-to-ground insulation resistance, the third resistor and the first resistor; The first series topology structure is composed of the fourth resistor and the fifth resistor; The second parallel topology structure is composed of the negative bus-to-ground insulation resistance and the resistance of the first series topology structure; According to the first proportional parameter, the resistance values on the first parallel topology structure and the second parallel topology structure, the current proportional equation is constructed.

5. The method of determining an insulation resistance according to claim 2, characterized by, The second closing switch strategy is that the first switch is opened and the second switch is closed; the first detection branch comprising the first switch and the second switch further comprises a first resistor and a second resistor; another detection branch comprises a third resistor, a fourth resistor and a fifth resistor; a first end of the first resistor is connected with a first end of the third resistor, a second end of the first resistor is connected with a first end of the first switch, a second end of the first switch and a first end of the second switch are connected with the preset grounding point; a second end of the second switch is connected with a first end of the second resistor, a second end of the second resistor is connected with a second end of the fifth resistor; a second end of the third resistor and a first end of the fourth resistor are connected with the preset grounding point and a first end of the third switch; a second end of the fourth resistor is connected with a first end of the fifth resistor; The current proportional equation is determined according to the negative bus voltage value and the positive bus voltage value, comprising: A second proportional parameter is determined based on the second negative bus voltage value and the second positive bus voltage value under the second closing switch strategy; In the case that the first switch is opened and the second switch is opened, a third parallel topology structure is formed by the positive bus ground insulation resistance and the third resistor; A first series topology structure is formed by the fourth resistor and the fifth resistor; A fourth parallel topology structure is formed by the negative bus ground insulation resistance, the resistor of the first series topology structure and the second resistor; The current proportional equation is constructed according to the second proportional parameter, the resistance values on the third parallel topology structure and the fourth parallel topology structure.

6. The method of determining an insulation resistance according to claim 1, characterized by, After the negative bus voltage value of the current stage is determined, before the corresponding positive bus voltage value is determined based on the negative bus voltage value of the current stage, further comprising: A first preset negative bus voltage value of the current preset collection time and a second preset negative bus voltage value of the last preset collection time are obtained; A first difference value is determined according to the first preset negative bus voltage value and the second preset negative bus voltage value; In the case that the first difference value does not exceed the first threshold value, it is determined that the insulation resistance detection circuit reaches a stable state, so as to enter the step of determining the corresponding positive bus voltage value based on the negative bus voltage value of the current stage.

7. The method of determining an insulation resistance according to claim 1, characterized by, After the negative bus voltage value of the current stage is determined, before the corresponding positive bus voltage value is determined based on the negative bus voltage value of the current stage, further comprising: The negative bus voltage value of the current stage is obtained as a third preset negative bus voltage value; A fourth preset negative bus voltage value after the third preset negative bus voltage value is filtered is obtained; A second difference value is determined according to the third preset negative bus voltage value and the fourth preset negative bus voltage value; In the case that the second difference value does not exceed the second threshold value and is maintained for a preset time, it is determined that the insulation resistance detection circuit reaches a stable state, so as to enter the step of determining the corresponding positive bus voltage value based on the negative bus voltage value of the current stage.

8. The method of determining an insulation resistance according to claim 1, characterized by, After the negative bus-to-ground voltage value of the current stage is determined, before the corresponding positive bus-to-ground voltage value is determined based on the negative bus-to-ground voltage value of the current stage, the method further comprises: obtaining each preset negative bus-to-ground voltage value and each preset positive bus-to-ground voltage value in a preset acquisition period; selecting a maximum preset negative bus-to-ground voltage value and a minimum preset negative bus-to-ground voltage value from the preset negative bus-to-ground voltage values, and determining a third difference value according to the maximum preset negative bus-to-ground voltage value and the minimum preset negative bus-to-ground voltage value; selecting a maximum preset positive bus-to-ground voltage value and a minimum preset positive bus-to-ground voltage value from the preset positive bus-to-ground voltage values, and determining a fourth difference value according to the maximum preset positive bus-to-ground voltage value and the minimum preset positive bus-to-ground voltage value; if the third difference value does not exceed a third threshold value and the fourth difference value does not exceed a fourth threshold value, it is determined that the insulation resistance detection circuit reaches a stable state, and the step of determining the corresponding positive bus-to-ground voltage value based on the negative bus-to-ground voltage value of the current stage is entered.

9. An apparatus for determining an insulation resistance, characterized by comprise: a memory for storing a computer program; a processor for executing the computer program to implement the steps of the insulation resistance determination method according to any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that, The computer program is stored on the computer readable storage medium and is executed by the processor to implement the steps of the insulation resistance determination method according to any one of claims 1 to 8.

Images