DC charging pile insulation test method, circuit, device and computer storage medium

Abstract

The present application relates to a DC charging pile insulation test method, circuit, device and storage medium. The circuit includes a positive switch, a negative switch, a first switch, a second switch, a first resistor, a second resistor, a third resistor and a fourth resistor. The method includes: controlling the positive switch and the negative switch to close, the first switch and the second switch to open, and obtaining the positive and negative bus voltages to the ground in the first state; controlling the positive switch, the negative switch and the first switch to close, the second switch to open, and obtaining the positive and negative bus voltages to the ground in the second state; controlling the positive switch, the negative switch and the second switch to close, the first switch to open, and obtaining the positive and negative bus voltages to the ground in the third state; obtaining the positive and negative bus resistances to the ground based on the positive and negative bus voltages to the ground in each state, and determining the insulation performance based on the resistances to the ground. This test method can meet the requirements of a wide range of DC charging pile voltage levels and has high measurement accuracy.

Description

Technical Field

[0001] The present application relates to the technical field of insulation testing, and in particular to a method, circuit, device and computer-readable storage medium for insulation testing of a DC charging pile. Background Art

[0002] DC charging piles are mechatronic devices for charging electric vehicle power batteries. Many of their components involve high voltages and have a relatively harsh working environment. Vibration, corrosion from acidic and alkaline gases, and changes in temperature and humidity may cause rapid aging of cables and other insulating materials or even insulation damage, greatly reducing the insulation strength of the equipment and endangering personal safety. Therefore, DC charging piles must have their own insulation detection function. When the insulation performance drops to the threshold and affects user safety, the power supply must be cut off to ensure user safety. The traditional method of performing insulation testing on DC charging piles has the problem of low sensitivity. Summary of the invention

[0003] Based on this, it is necessary to provide a DC charging pile insulation testing method, circuit, device and computer storage medium that can highly sensitively confirm the insulation performance of the DC charging pile in response to the above technical problems.

[0004] In the first aspect, an embodiment of the present invention provides a DC charging pile insulation test method, which is applied to a DC charging pile insulation test circuit. The DC charging pile includes a positive bus and a negative bus. The DC charging pile insulation test circuit includes a positive switch, a negative switch, a first switch, a second switch, a first resistor, a second resistor, a third resistor, and a fourth resistor; the first end of the positive switch is connected to the positive bus; the first end of the first resistor is connected to the second end of the positive switch, and the second end of the first resistor is grounded through the first switch; the first end of the second resistor is connected to the second end of the positive switch, and the second end of the second resistor is grounded; the first end of the negative switch is connected to the negative bus; the first end of the third resistor is connected to the second end of the negative switch, and the second end of the third resistor is grounded through the second switch; the first end of the fourth resistor is connected to the second end of the negative switch, and the second end of the fourth resistor is grounded; the insulation test method includes: controlling the positive switch and the negative switch to close, and controlling the first switch and the second switch to open, so that the DC charging pile insulation test circuit enters the first state, and obtain the positive bus-to-ground voltage and the negative bus-to-ground voltage in the first state; control the positive switch, the negative switch and the first switch to be closed, and control the second switch to be disconnected, so that the DC charging pile insulation test circuit enters the second state, and obtains the positive bus-to-ground voltage and the negative bus-to-ground voltage in the second state; control the positive switch, the negative switch and the second switch to be closed, and control the first switch to be disconnected, so that the DC charging pile insulation test circuit enters the third state, and obtains the positive bus-to-ground voltage and the negative bus-to-ground voltage in the third state; based on the positive bus-to-ground voltage and the negative bus-to-ground voltage in the first state, and the positive bus-to-ground voltage and the negative bus-to-ground voltage in the second state, determine the positive bus-to-ground resistance; based on the positive bus-to-ground voltage and the negative bus-to-ground voltage in the first state, and the positive bus-to-ground voltage and the negative bus-to-ground voltage in the third state, determine the negative bus-to-ground resistance; determine the insulation performance of the DC charging pile based on the positive bus-to-ground resistance and the negative bus-to-ground resistance.

[0005] In one embodiment, based on the positive bus-to-ground voltage and the negative bus-to-ground voltage in the first state and the positive bus-to-ground voltage and the negative bus-to-ground voltage in the second state, the step of determining the positive bus-to-ground resistance includes:

[0006] The positive bus-to-ground voltage and the negative bus-to-ground voltage in the first state and the positive bus-to-ground voltage and the negative bus-to-ground voltage in the second state are input into the first relational expression to obtain the positive bus-to-ground resistance; the first relational expression is:

[0007]

[0008] Among them, R p is the resistance of the positive busbar to ground, U p0 is the positive bus voltage to ground in the first state, Un0 is the negative bus voltage to ground in the first state, U np1 is the voltage of the negative busbar to ground in the second state, U pp1 is the positive bus voltage to ground in the second state, R c1 is the parallel equivalent resistance of the first resistor and the second resistor.

[0009] In one embodiment, based on the positive bus-to-ground voltage and the negative bus-to-ground voltage in the first state and the positive bus-to-ground voltage and the negative bus-to-ground voltage in the third state, the step of determining the negative bus-to-ground resistance includes:

[0010] The positive bus-to-ground voltage and the negative bus-to-ground voltage in the first state and the positive bus-to-ground voltage and the negative bus-to-ground voltage in the third state are input into the second relational expression to obtain the negative bus-to-ground resistance; the second relational expression is:

[0011]

[0012] Among them, R n is the resistance of the negative busbar to ground, U p0 is the positive bus voltage to ground in the first state, U n0 is the negative bus voltage to ground in the first state, U np2 is the voltage between the negative busbar and the ground in the third state, U pp2 is the positive bus voltage to ground in the third state, R c2 is the parallel equivalent resistance of the third resistor and the fourth resistor.

[0013] In one embodiment, the first resistor is the same as the third resistor; the second resistor includes a first current limiting resistor and a first voltage dividing resistor, the fourth resistor includes a second current limiting resistor and a second voltage dividing resistor, the first current limiting resistor is the same as the second current limiting resistor, and the first voltage dividing resistor is the same as the second voltage dividing resistor; the first end of the first current limiting resistor is connected to the second end of the positive switch, and the second end of the first current limiting resistor is grounded through the first voltage dividing resistor; the first end of the second current limiting resistor is connected to the second end of the negative switch, and the second end of the second current limiting resistor is grounded through the second voltage dividing resistor;

[0014] The step of obtaining the positive bus voltage to ground and the negative bus voltage to ground in the first state includes: obtaining the first voltage-dividing resistor voltage to ground and the second voltage-dividing resistor voltage to ground in the first state; taking the first voltage-dividing resistor voltage to ground in the first state as the positive bus voltage to ground in the first state, and taking the second voltage-dividing resistor voltage to ground in the first state as the negative bus voltage to ground in the first state;

[0015] The step of obtaining the positive bus voltage to ground and the negative bus voltage to ground in the second state includes: obtaining the first voltage-dividing resistor to ground voltage and the second voltage-dividing resistor to ground voltage in the second state; taking the first voltage-dividing resistor to ground voltage in the second state as the positive bus voltage to ground in the second state, and taking the second voltage-dividing resistor to ground voltage in the second state as the negative bus voltage to ground in the second state;

[0016] The step of obtaining the positive bus voltage to ground and the negative bus voltage to ground in the third state includes: obtaining the first voltage-dividing resistor voltage to ground and the second voltage-dividing resistor voltage to ground in the third state; taking the first voltage-dividing resistor voltage to ground in the third state as the positive bus voltage to ground in the third state, and taking the second voltage-dividing resistor voltage to ground in the third state as the negative bus voltage to ground in the third state.

[0017] In a second aspect, an embodiment of the present invention provides a DC charging pile insulation test circuit, the DC charging pile includes a positive bus and a negative bus, and the DC charging pile insulation test circuit includes: a positive switch, a first end of which is connected to the positive bus; a first resistor, a first end of which is connected to the second end of the positive switch, and the second end is grounded through the first switch; a second resistor, a first end of which is connected to the second end of the positive switch, and the second end is grounded; a negative switch, a first end of which is connected to the negative bus; a third resistor, a first end of which is connected to the second end of the negative switch, and the second end is grounded through the second switch; a fourth resistor, a first end of which is connected to the second end of the negative switch, and the second end is grounded; a controller, connected to the positive switch, the negative switch, the first switch and the second switch, including a memory and a processor, the memory stores a computer program, and the processor implements the above-mentioned DC charging pile insulation test method when executing the computer program.

[0018] In one embodiment, the first resistor is the same as the third resistor; the second resistor includes a first current limiting resistor and a first voltage dividing resistor, the fourth resistor includes a second current limiting resistor and a second voltage dividing resistor, the first current limiting resistor is the same as the second current limiting resistor, and the first voltage dividing resistor is the same as the second voltage dividing resistor; the first end of the first current limiting resistor is connected to the second end of the positive switch, and the second end of the first current limiting resistor is grounded through the first voltage dividing resistor; the first end of the second current limiting resistor is connected to the second end of the negative switch, and the second end of the second current limiting resistor is grounded through the second voltage dividing resistor; the controller is connected to the first common end and the second common end respectively; the first common end is the common end of the first current limiting resistor and the first voltage dividing resistor, and the second common end is the common end of the second current limiting resistor and the second voltage dividing resistor.

[0019] In one embodiment, the controller is connected to the first common terminal via a first optical coupling isolation unit, and the controller is connected to the second common terminal via a second optical coupling isolation unit.

[0020] In one embodiment, the positive switch, the negative switch, the first switch and the second switch all include relays.

[0021] In a third aspect, an embodiment of the present invention provides a DC charging pile insulation test device, which is applied to a DC charging pile insulation test circuit. The DC charging pile includes a positive bus and a negative bus. The DC charging pile insulation test circuit includes a positive switch, a negative switch, a first switch, a second switch, a first resistor, a second resistor, a third resistor, and a fourth resistor; the first end of the positive switch is connected to the positive bus; the first end of the first resistor is connected to the second end of the positive switch, and the second end of the first resistor is grounded through the first switch; the first end of the second resistor is connected to the second end of the positive switch, and the second end of the second resistor is grounded; the first end of the negative switch is connected to the negative bus; the first end of the third resistor is connected to the second end of the negative switch, and the second end of the third resistor is grounded through the second switch; the first end of the fourth resistor is connected to the second end of the negative switch, and the second end of the fourth resistor is grounded; the insulation test device includes: a data acquisition module, which is used to control the positive switch and the negative switch to be closed, and control the first switch and the second switch to be disconnected, so that the DC charging pile insulation test circuit enters a first state, and acquires the first state The positive bus voltage to ground and the negative bus voltage to ground under the control of the positive switch, the negative switch and the first switch are closed, and the second switch is controlled to be disconnected, so that the DC charging pile insulation test circuit enters the second state, and the positive bus voltage to ground and the negative bus voltage to ground under the second state are obtained; the positive switch, the negative switch and the second switch are controlled to be closed, and the first switch is controlled to be disconnected, so that the DC charging pile insulation test circuit enters the third state, and the positive bus voltage to ground and the negative bus voltage to ground under the third state are obtained; the first processing module , used to determine the positive bus-to-ground resistance based on the positive bus-to-ground voltage and the negative bus-to-ground voltage in the first state, and the positive bus-to-ground voltage and the negative bus-to-ground voltage in the second state; the second processing module is used to determine the negative bus-to-ground resistance based on the positive bus-to-ground voltage and the negative bus-to-ground voltage in the first state, and the positive bus-to-ground voltage and the negative bus-to-ground voltage in the third state; the insulation performance determination module is used to determine the insulation performance of the DC charging pile based on the positive bus-to-ground resistance and the negative bus-to-ground resistance.

[0022] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon, and the computer program implements the steps of the above method when executed by a processor.

[0023] Based on any of the above embodiments, by controlling the imbalance of the DC charging pile insulation test circuit in different states, the quantitative relationship between the positive bus voltage to ground and the negative bus voltage to ground in each state is constructed, thereby solving the positive bus resistance to ground and the negative bus resistance to ground, and the insulation performance of the DC charging pile can be judged according to the positive bus resistance to ground and the negative bus resistance to ground. This test method can meet the requirements of a wide range of DC charging pile voltage levels and has high measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 It is a structural schematic diagram of a DC charging pile insulation test circuit in one embodiment;

[0026] Figure 2 A schematic diagram of a flow chart of a DC charging pile insulation test method in one embodiment;

[0027] Figure 3 A schematic diagram of the structure of a DC charging pile insulation test circuit in another embodiment

[0028] Figure 4 A schematic diagram of a circuit for testing the voltage between the positive busbar and the ground in a DC charging pile insulation test circuit in one embodiment;

[0029] Figure 5 A schematic diagram of a circuit for testing the voltage between the negative busbar and the ground in a DC charging pile insulation test circuit in one embodiment;

[0030] Figure 6 The figure is a circuit diagram of a controller in a DC charging pile insulation test circuit in one embodiment. DETAILED DESCRIPTION

[0031] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0033] It can be understood that the terms "first", "second", etc. used in the present application can be used in this article to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from another element.

[0034] Spatially relative terms such as "under," "beneath," "below," "under," "above," "above," and the like may be used herein to describe the relationship of an element or feature shown in the figures to other elements or features. It should be understood that, in addition to the orientations shown in the figures, spatially relative terms also include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is flipped, an element or feature described as "under other elements" or "under it" or "under it" will be oriented as being "above" the other elements or features. Thus, the exemplary terms "under" and "under" may include both upper and lower orientations. In addition, the device may also include additional orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptors used herein are interpreted accordingly.

[0035] It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element, or connected to the other element through an intermediate element. In addition, the "connection" in the following embodiments should be understood as "electrical connection", "communication connection", etc. if there is transmission of electrical signals or data between the connected objects.

[0036] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the relevant listed items.

[0037] The embodiment of the present invention provides a DC charging pile insulation test method, which is applied to a DC charging pile insulation test circuit. The DC charging pile insulation test circuit can be referred to Figure 1 Specifically, the DC charging pile includes a positive busbar and a negative busbar. The insulation performance of the DC charging pile can generally be calculated based on the resistance R pAnd the negative busbar to ground resistance R n Determine, the positive busbar to ground resistance R p It is the resistance between the positive busbar and the ground chassis, and the resistance between the negative busbar and the ground R n The DC charging pile insulation test circuit includes a positive switch Sp, a negative switch S n , 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. p The first end of the first resistor R1 is connected to the positive switch S p The second end of the first resistor R1 is connected to the positive electrode switch S1, and the second end of the first resistor R2 is connected to the positive electrode switch S1. p The second end of the second resistor R2 is connected to the ground. n The first end of the third resistor R3 is connected to the negative switch S n The second end of the third resistor R3 is connected to the ground through the second switch S2. The first end of the fourth resistor R4 is connected to the negative electrode switch S n , and a second end of the fourth resistor R4 is grounded.

[0038] See also Figure 2 , the insulation testing method includes steps S202 to S212.

[0039] S202, controls the positive switch S p , negative switch S n Close, control the first switch S1 and the second switch S2 to open, so that the DC charging pile insulation test circuit enters the first state, and obtains the positive bus-to-ground voltage and the negative bus-to-ground voltage in the first state.

[0040] It can be understood that this is equivalent to the positive busbar to ground resistance R p The second resistor R2 is connected in parallel between the positive busbar and the ground chassis, and the negative busbar to ground resistance R n The fourth resistor R4 is connected in parallel between the negative bus and the ground chassis. According to Kirchhoff's current law, when the second resistor R2 is the same as the fourth resistor R4, the current flowing into the chassis of the second resistor R2 and the fourth resistor R4 is equal. Therefore, the negative bus resistance R n , Positive busbar to ground resistance R p The current flowing into the chassis should also be equal, and the resistance of the negative busbar to the ground R n , Positive busbar to ground resistance R p The current flowing into the ground chassis can be calculated according to the positive bus voltage to ground and the negative bus voltage to ground in the first state, that is:

[0041]

[0042] Among them, U p0 is the positive bus voltage to ground in the first state, U n0 is the voltage of the negative bus to ground in the first state.

[0043] S204, control the positive switch S p , negative switch S n The first switch S1 is closed, and the second switch S2 is controlled to be open, so that the DC charging pile insulation test circuit enters the second state, and the positive bus-to-ground voltage and the negative bus-to-ground voltage in the second state are obtained.

[0044] It can be understood that this is equivalent to the positive busbar to ground resistance R p The first resistor R1 and the second resistor R2 are connected in parallel between the positive bus and the ground chassis, and the negative bus to ground resistance R n The fourth resistor R4 is connected in parallel between the negative bus and the ground chassis. Since the circuit structures on the positive bus and the negative bus are asymmetrical, according to Kirchhoff's current law, the positive bus to ground resistance R p The sum of the current flowing into the ground chassis, the current flowing into the ground chassis through the first resistor R1, and the current flowing into the ground chassis through the second resistor R2 should be equal to the negative busbar to ground resistance R n The current flowing into the ground chassis. The negative busbar to ground resistance R n The current flowing into the ground chassis and the sum of the above currents can be calculated according to the positive bus voltage to ground and the negative bus voltage to ground in the second state, that is,

[0045]

[0046] Among them, U np1 is the voltage of the negative busbar to ground in the second state, U pp1 is the positive bus voltage to ground in the second state, R c1 is the parallel equivalent resistance of the first resistor and the second resistor.

[0047] S206, control the positive switch S p , negative switch S n The second switch S2 is closed, and the first switch S1 is controlled to be open, so that the DC charging pile insulation test circuit enters the third state, and the positive bus-to-ground voltage and the negative bus-to-ground voltage in the third state are obtained.

[0048] It can be understood that this is equivalent to the positive busbar to ground resistance R p The second resistor R2 is connected in parallel between the positive busbar and the ground chassis, and the negative busbar to ground resistance R nThe third resistor R3 and the fourth resistor R4 are connected in parallel between the negative bus and the ground chassis. Since the circuit structures on the positive bus and the negative bus are asymmetrical, according to Kirchhoff's current law, the negative bus resistance to ground R n The sum of the current flowing into the ground chassis, the current flowing into the ground chassis through the third resistor R3, and the current flowing into the ground chassis through the fourth resistor R4 should be equal to the positive busbar to ground resistance R p The current flowing into the ground chassis. The positive busbar to ground resistance R p The current flowing into the ground chassis and the sum of the above currents can be calculated according to the positive busbar-to-ground voltage and the negative busbar-to-ground voltage in the third state, that is,

[0049]

[0050] Among them, U np2 is the voltage between the negative busbar and the ground in the third state, U pp2 is the positive bus voltage to ground in the third state, R c2 is the parallel equivalent resistance of the third resistor and the fourth resistor.

[0051] S208, determining the positive bus-to-ground resistance R based on the positive bus-to-ground voltage and the negative bus-to-ground voltage in the first state and the positive bus-to-ground voltage and the negative bus-to-ground voltage in the second state p .

[0052] Specifically, in the above equations (1) and (2), only the positive busbar-to-ground resistance R p And the negative busbar to ground resistance R n Two unknowns, replace R in the above formula (1) n Substituting into formula (2), we can get the positive busbar to ground resistance R p The expression of , that is, the first relation:

[0053]

[0054] Among them, R p is the resistance of the positive busbar to ground, U p0 is the positive bus voltage to ground in the first state, U n0 is the negative bus voltage to ground in the first state, U pp1 is the positive bus voltage to ground in the second state, U np1 is the negative bus voltage to ground in the second state, R c1 The positive bus-to-ground resistance R is obtained by inputting the positive bus-to-ground voltage and the negative bus-to-ground voltage in the first state and the positive bus-to-ground voltage and the negative bus-to-ground voltage in the second state into the first relational expression. p .

[0055] S210, determining the negative bus-to-ground resistance R based on the positive bus-to-ground voltage and the negative bus-to-ground voltage in the first state and the positive bus-to-ground voltage and the negative bus-to-ground voltage in the third state. n .

[0056] Specifically, in the above equations (1) and (3), only the positive busbar-to-ground resistance R p And the negative busbar to ground resistance R n Two unknowns, replace R in the above formula (1) p Substituting into formula (3), we can get the positive busbar to ground resistance R n The expression of , that is, the second relation:

[0057]

[0058] Among them, R n is the resistance of the negative busbar to ground, U p0 is the positive bus voltage to ground in the first state, U n0 is the negative bus voltage to ground in the first state, U np2 is the voltage between the negative busbar and the ground in the third state, U pp2 is the positive bus voltage to ground in the third state, R c2 The parallel equivalent resistance of the third resistor R3 and the fourth resistor R4. The positive bus-to-ground voltage and the negative bus-to-ground voltage in the first state, and the positive bus-to-ground voltage and the negative bus-to-ground voltage in the third state are input into the third relational expression to obtain the negative bus-to-ground resistance R n .

[0059] S212, based on the positive busbar to ground resistance R p , Negative busbar to ground resistance R n Determine the insulation performance of the DC charging pile.

[0060] When the insulation capacity of the DC charging pile is good, the positive busbar to ground resistance R p And the negative busbar to ground resistance R n They should all be greater than the threshold resistance, that is, the DC charging pile is insulated from the ground.

[0061] Based on the DC charging pile insulation test method in this embodiment, by controlling the imbalance of the DC charging pile insulation test circuit in different states, the quantitative relationship between the positive bus voltage to ground and the negative bus voltage to ground in each state is constructed, thereby solving the positive bus resistance to ground R p , Negative busbar to ground resistance R n , according to the positive busbar to ground resistance R p , Negative busbar to ground resistance R nThe insulation performance of the DC charging pile can be judged. This test method can meet the requirements of a wide range of DC charging pile voltage levels and has high measurement accuracy.

[0062] In one embodiment, the DC charging pile insulation test circuit is shown in Figure 3 , the first resistor R1 is the same as the third resistor R3. The second resistor R2 includes a first current limiting resistor R 22 and the first voltage divider resistor R 24 The fourth resistor R4 includes a second current limiting resistor R 42 and the second voltage divider resistor R 44 The first current limiting resistor R 22 The second current limiting resistor R 42 The first voltage divider resistor R 24 The second voltage divider resistor R 44 The first current limiting resistor R 22 The first end of the positive switch S p The second end of the first current limiting resistor R 22 The second end of the resistor R 24 Ground. The second current limiting resistor R 42 The first end of the negative switch S n The second end of the second current limiting resistor R 42 The second end of the resistor R 44 It is understandable that due to the large voltage level span of the DC charging pile, the range of ordinary voltage sensors is difficult to meet the direct test of the positive bus or negative bus voltage to ground. Therefore, this embodiment places the test point of the positive bus voltage to ground at the first current limiting resistor R 22 The second end (i.e. Figure 3 The positive test point of the negative busbar to ground voltage is placed at the second current limiting resistor R 42 The second end (i.e. Figure 3 Taking the positive test point as an example, due to the second resistor R2 and the positive busbar to ground resistance R p The voltages of the two resistors are equal, and the voltage obtained from the positive test point is less than the voltage of the positive busbar to the ground, which can adapt to the range of the general voltage sensor and can be adjusted according to the first current limiting resistor R 22 and the first voltage divider resistor R 24 The relationship between the positive busbar and the ground voltage is obtained, which will not affect the measurement effect. In addition, the first current limiting resistor R 22 This ensures that the current is not too large, ensuring the safety of the test process. The principle of negative testing is similar and will not be repeated here.

[0063] based on Figure 3The circuit structure in which the step of obtaining the positive bus voltage to ground and the negative bus voltage to ground in the first state includes: obtaining the first voltage-dividing resistor R in the first state 24 The voltage to ground and the second voltage-dividing resistor R 44 voltage to ground; with the first voltage-dividing resistor R in the first state 24 The voltage to ground is the voltage of the positive bus to ground in the first state, and the voltage of the second voltage-dividing resistor R in the first state is 44 The voltage to ground is the voltage of the negative bus bar to ground in the first state.

[0064] The step of obtaining the positive bus voltage to ground and the negative bus voltage to ground in the second state includes: obtaining the first voltage-dividing resistor R in the second state 24 The voltage to ground and the second voltage-dividing resistor R 44 voltage to ground; with the first voltage-dividing resistor R in the second state 24 The voltage to ground is the voltage of the positive bus to ground in the second state, and the voltage of the second voltage-dividing resistor R in the second state is 44 The voltage to ground is the voltage of the negative bus to ground in the second state;

[0065] The step of obtaining the positive bus-to-ground voltage and the negative bus-to-ground voltage in the third state includes: obtaining the first voltage-dividing resistor R in the third state 24 The voltage to ground and the second voltage-dividing resistor R 44 voltage to ground; with the first voltage-dividing resistor R in the third state 24 The voltage to ground is the voltage of the positive bus to ground in the third state, and the voltage of the second voltage-dividing resistor R in the third state is 44 The voltage to ground is the voltage of the negative bus bar to ground in the third state.

[0066] Specifically, in order to avoid the need for the first voltage-dividing resistor R 24 The voltage to ground is used to calculate the positive bus voltage to ground and the voltage to ground is calculated based on the second voltage-dividing resistor R 44 The trouble of calculating the voltage of the negative busbar to ground is to select the first current limiting resistor R 22 The second current limiting resistor R 42 Set to the same, the first voltage divider resistor R 24 The second voltage divider resistor R 44 Set to, then the first voltage divider resistor R 24 The first quantitative relationship between the voltage to ground and the voltage to ground of the positive busbar (obtained by series voltage division), the second voltage dividing resistor R 44 The second quantitative relationship between the voltage to ground and the voltage to ground of the negative busbar is the same (which can be obtained according to the series voltage division), so the first voltage dividing resistor R can be directly used in the above equations (1), (2), and (3). 24 The voltage to ground replaces the positive bus voltage to ground, and the second voltage divider resistor R44 The voltage to ground replaces the negative bus voltage to ground.

[0067] It should be understood that although Figure 2 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, Figure 2 At least part of the steps may include multiple steps or multiple stages. These steps or stages are not necessarily performed at the same time, but can be performed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed in turn or alternately with other steps or at least part of the steps or stages in other steps.

[0068] See also Figure 1 The embodiment of the present invention provides a DC charging pile insulation test circuit, wherein the DC charging pile includes a positive busbar and a negative busbar. The DC charging pile insulation test circuit includes: a positive switch S p , the first end is connected to the positive bus; the first resistor R1, the first end is connected to the positive switch S p The second end of the second resistor R2 is connected to the positive switch S p The second end of the negative switch S is connected to the ground; n , the first end is connected to the negative bus; the third resistor R3, the first end is connected to the negative switch S n The second end of the fourth resistor R4 is connected to the negative electrode switch S n The second end is connected to the ground; the controller is connected to the positive switch S p , negative switch S n , a first switch S1 and a second switch S2 are connected, including a memory and a processor, the memory stores a computer program, and the processor implements the above-mentioned DC charging pile insulation test method when executing the computer program.

[0069] Based on the DC charging pile insulation test circuit in this embodiment, by controlling the imbalance of the DC charging pile insulation test circuit in different states, the quantitative relationship between the positive bus voltage to ground and the negative bus voltage to ground in each state is constructed, thereby solving the positive bus resistance to ground R p , Negative busbar to ground resistance R n , according to the positive busbar to ground resistance R p , Negative busbar to ground resistance R nThe insulation performance of the DC charging pile can be judged. This test circuit can meet the wide range requirements of DC charging pile voltage levels and has high measurement accuracy.

[0070] In one embodiment, the first resistor R1 is the same as the third resistor R3; the second resistor R2 includes a first current limiting resistor R 22 and the first voltage divider resistor R 24 The fourth resistor R4 includes a second current limiting resistor R 42 and the second voltage divider resistor R 44 , the first current limiting resistor R 22 The second current limiting resistor R 42 The first voltage divider resistor R 24 The second voltage divider resistor R 44 Same; the first current limiting resistor R 22 The first end of the positive switch S p The second end of the first current limiting resistor R 22 The second end of the resistor R 24 Ground; the second current limiting resistor R 42 The first end of the negative switch S n The second end of the second current limiting resistor R 42 The second end of the resistor R 44 Ground; the controller is connected to the first common terminal and the second common terminal respectively; the first common terminal is the first current limiting resistor R 22 and the first voltage divider resistor R 24 The second common terminal is the second current limiting resistor R 42 and the second voltage divider resistor R 44 The public end of the

[0071] In one embodiment, the controller is connected to the first common terminal via a first optical coupling isolation unit, and the controller is connected to the second common terminal via a second optical coupling isolation unit. It can be understood that the anti-interference ability of signal transmission can be increased through optical coupling isolation, and the accuracy of insulation testing can be further ensured.

[0072] In one embodiment, the positive switch S p , negative switch S n , the first switch S1 and the second switch S2 each include a relay.

[0073] In a specific embodiment, see Figure 4 , the positive switch S in the figure p The controller includes a relay RL551, which is connected to the base of the transistor Q551. The relay RL551 is powered on or off by controlling the on and off of the transistor Q551, thereby controlling the positive switch S pIn the figure, resistors B551, R554, R555, R556, R557, R558, R559, and R564 together constitute the first current limiting resistor R 22 The resistor R568 in the figure is the first voltage divider resistor R 24 , VIN_DC1+ in the figure is the positive test point. The resistor R560 in the figure is the first resistor R1. The first switch S1 includes a relay RL552, and the controller is connected to the base of the transistor Q552, and controls the on and off of the transistor Q552 to power on or off the relay RL552, thereby controlling the on and off of the first switch S1.

[0074] In a specific embodiment, see Figure 5 , the negative switch S in the figure n The controller includes a relay RL601, which is connected to the base of the transistor Q601. The relay RL601 is powered on or off by controlling the on and off of the transistor Q601, thereby controlling the negative switch S n The resistors B601, R603, R604, R605, R606, R607, R608 and R613 in the figure together constitute the second current limiting resistor R 42 The resistor R617 in the figure is the second voltage divider resistor R 44 , VIN_DC1- in the figure is the negative test point. Resistor R609 in the figure is the third resistor R3. The second switch S2 includes a relay RL602, and the controller is connected to the base of the transistor Q602, and controls the on and off of the transistor Q602 to power on or off the relay RL602, thereby controlling the on and off of the second switch S2.

[0075] In a specific embodiment, see Figure 6 The controller may include a metering chip RN8209C, which receives the positive bus voltage to ground in each state through pin 5, and receives the negative bus voltage to ground in each state through pin 7. The metering chip RN8209C can perform analog-to-digital conversion on the signal, and calculate the positive bus resistance to ground R using the expression in the above embodiment for the converted data. p And the negative busbar to ground resistance R n .

[0076] The embodiment of the present invention provides a DC charging pile insulation test device, which is applied to a DC charging pile insulation test circuit. The DC charging pile insulation test circuit can be referred to Figure 1 The DC charging pile includes a positive busbar and a negative busbar. The DC charging pile insulation test circuit includes a positive switch S p , negative switch S n, 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. The first end of the positive switch Sp is connected to the positive bus. The first end of the first resistor R1 is connected to the second end of the positive switch Sp, and the second end of the first resistor R1 is grounded through the first switch S1. The first end of the second resistor R2 is connected to the second end of the positive switch Sp, and the second end of the second resistor R2 is grounded. The negative switch S n The first end of the third resistor R3 is connected to the negative switch S n The second end of the third resistor R3 is connected to the ground through the second switch S2. The first end of the fourth resistor R4 is connected to the negative electrode switch S n The second end of the fourth resistor R4 is connected to the ground. The insulation testing device includes a data acquisition module, a first processing module, a second processing module and an insulation performance determination module.

[0077] The data acquisition module is used to control the positive switch Sp and the negative switch S n Close, control the first switch S1 and the second switch S2 to open, so that the DC charging pile insulation test circuit enters the first state, and obtains the positive bus-to-ground voltage and the negative bus-to-ground voltage in the first state; control the positive switch Sp and the negative switch S n The first switch S1 is closed, and the second switch S2 is controlled to be open, so that the DC charging pile insulation test circuit enters the second state, and the positive bus voltage to ground and the negative bus voltage to ground in the second state are obtained; the positive switch Sp and the negative switch S n The second switch S2 is closed, and the first switch S1 is controlled to be open, so that the DC charging pile insulation test circuit enters the third state, and the positive bus-to-ground voltage and the negative bus-to-ground voltage in the third state are obtained.

[0078] The first processing module is used to determine the positive bus-to-ground resistance Rp based on the positive bus-to-ground voltage and the negative bus-to-ground voltage in the first state and the positive bus-to-ground voltage and the negative bus-to-ground voltage in the second state.

[0079] The second processing module is used to determine the negative bus-to-ground resistance R based on the positive bus-to-ground voltage and the negative bus-to-ground voltage in the first state and the positive bus-to-ground voltage and the negative bus-to-ground voltage in the third state. n .

[0080] The insulation performance determination module is used to determine the insulation performance of the positive busbar based on the ground resistance Rp and the negative busbar ground resistance R n Determine the insulation performance of the DC charging pile.

[0081] For the specific limitations of the DC charging pile insulation test device, please refer to the limitations of the DC charging pile insulation test method above, which will not be repeated here. Each module in the above-mentioned DC charging pile insulation test device can be implemented in whole or in part by software, hardware and a combination thereof. The above-mentioned 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 in the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules. It should be noted that the division of modules in the embodiment of the present application is schematic and is only a logical function division. There may be other division methods in actual implementation.

[0082] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon, and the computer program implements the steps of the above method when executed by a processor.

[0083] A person skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. 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 at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (Read-O n Volatile memory may include random access memory (RAM), magnetic tape, floppy disk, flash memory, or optical storage. n dom Access Memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in many forms, such as static random access memory (Static Random Access Memory, n dom Access Memory, SRAM) or Dynamic Random Access Memory (Dy n amic Ra n dom Access Memory, DRAM), etc.

[0084] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", "ideal embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

[0085] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0086] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A DC charging pile insulation test method, characterized in that: Applied to the insulation test circuit of a DC charging pile, the DC charging pile includes a positive bus and a negative bus, and the insulation test circuit of the DC charging pile includes a positive switch, a negative switch, a first switch, a second switch, a first resistor, a second resistor, a third resistor, and a fourth resistor; the first end of the positive switch is connected to the positive bus; the first end of the first resistor is connected to the second end of the positive switch, and the second end of the first resistor is grounded through the first switch; the first end of the second resistor is connected to the second end of the positive switch, and the second end of the second resistor is grounded; the first end of the negative switch is connected to the negative bus; the first end of the third resistor is connected to the second end of the negative switch, and the second end of the third resistor is grounded through the second switch; the first end of the fourth resistor is connected to the second end of the negative switch, and the second end of the fourth resistor is grounded; The insulation testing method comprises: Control the positive switch and the negative switch to close, and control the first switch and the second switch to open, so that the DC charging pile insulation test circuit enters a first state, and obtains the positive bus-to-ground voltage and the negative bus-to-ground voltage in the first state; Control the positive switch, the negative switch and the first switch to be closed, and control the second switch to be opened, so that the DC charging pile insulation test circuit enters a second state, and obtains the positive bus-to-ground voltage and the negative bus-to-ground voltage in the second state; Control the positive switch, the negative switch and the second switch to close, and control the first switch to open, so that the DC charging pile insulation test circuit enters a third state, and obtains the positive bus-to-ground voltage and the negative bus-to-ground voltage in the third state; Determine the positive bus-to-ground resistance based on the positive bus-to-ground voltage and the negative bus-to-ground voltage in the first state and the positive bus-to-ground voltage and the negative bus-to-ground voltage in the second state; Determine the negative bus-to-ground resistance based on the positive bus-to-ground voltage and the negative bus-to-ground voltage in the first state and the positive bus-to-ground voltage and the negative bus-to-ground voltage in the third state; Determining the insulation performance of the DC charging pile based on the positive busbar-to-ground resistance and the negative busbar-to-ground resistance; The step of determining the positive bus-to-ground resistance based on the positive bus-to-ground voltage and the negative bus-to-ground voltage in the first state and the positive bus-to-ground voltage and the negative bus-to-ground voltage in the second state comprises: The positive bus-to-ground voltage and the negative bus-to-ground voltage in the first state and the positive bus-to-ground voltage and the negative bus-to-ground voltage in the second state are input into a first relational expression to obtain the positive bus-to-ground resistance; the first relational expression is: in, R p is the positive busbar-to-ground resistance, U p0 is the voltage of the positive busbar to ground in the first state, U n0 is the voltage of the negative bus to ground in the first state, U np1 is the voltage of the negative bus to ground in the second state, U pp1 is the positive bus voltage to ground in the second state, R c1 is the parallel equivalent resistance of the first resistor and the second resistor; The step of determining the negative bus-to-ground resistance based on the positive bus-to-ground voltage and the negative bus-to-ground voltage in the first state and the positive bus-to-ground voltage and the negative bus-to-ground voltage in the third state comprises: The positive bus-to-ground voltage and the negative bus-to-ground voltage in the first state and the positive bus-to-ground voltage and the negative bus-to-ground voltage in the third state are input into a second relational expression to obtain the negative bus-to-ground resistance; the second relational expression is: in, R n is the negative busbar-to-ground resistance, U p0 is the voltage of the positive busbar to ground in the first state, U n0 is the voltage of the negative bus to ground in the first state, U np2 is the voltage of the negative bus bar to ground in the third state, U pp2 is the voltage of the positive busbar to ground in the third state, R c2 is the parallel equivalent resistance of the third resistor and the fourth resistor; The first resistor is the same as the third resistor; the second resistor includes a first current limiting resistor and a first voltage dividing resistor, the fourth resistor includes a second current limiting resistor and a second voltage dividing resistor, the first current limiting resistor is the same as the second current limiting resistor, and the first voltage dividing resistor is the same as the second voltage dividing resistor; the first end of the first current limiting resistor is connected to the second end of the positive switch, and the second end of the first current limiting resistor is grounded through the first voltage dividing resistor; the first end of the second current limiting resistor is connected to the second end of the negative switch, and the second end of the second current limiting resistor is grounded through the second voltage dividing resistor; The step of obtaining the positive bus voltage to ground and the negative bus voltage to ground in the first state comprises: Acquire a voltage between a first voltage-dividing resistor and ground and a voltage between a second voltage-dividing resistor and ground in the first state; The voltage between the first voltage-dividing resistor and the ground in the first state is taken as the voltage between the positive bus bar and the ground in the first state, and the voltage between the second voltage-dividing resistor and the ground in the first state is taken as the voltage between the negative bus bar and the ground in the first state; The step of obtaining the positive bus-to-ground voltage and the negative bus-to-ground voltage in the second state comprises: Acquire a voltage between the first voltage-dividing resistor and the ground and a voltage between the second voltage-dividing resistor and the ground in the second state; The voltage between the first voltage-dividing resistor and the ground in the second state is taken as the voltage between the positive bus bar and the ground in the second state, and the voltage between the second voltage-dividing resistor and the ground in the second state is taken as the voltage between the negative bus bar and the ground in the second state; The step of obtaining the positive bus voltage to ground and the negative bus voltage to ground in the third state comprises: Acquire the voltage between the first voltage-dividing resistor and the ground and the voltage between the second voltage-dividing resistor and the ground in the third state; The voltage of the first voltage-dividing resistor to ground in the third state is taken as the voltage of the positive bus bar to ground in the third state, and the voltage of the second voltage-dividing resistor to ground in the third state is taken as the voltage of the negative bus bar to ground in the third state.

2. A DC charging pile insulation test circuit, characterized in that: The DC charging pile includes a positive busbar and a negative busbar, and the DC charging pile insulation test circuit includes: A positive switch, a first end of which is connected to the positive bus; a first resistor, a first end of which is connected to the second end of the positive switch, and a second end of which is grounded through the first switch; a second resistor, a first end of which is connected to the second end of the positive switch, and a second end of which is grounded; A negative switch, a first end of which is connected to the negative bus; a third resistor, a first end of which is connected to the second end of the negative switch, and a second end of which is grounded through the second switch; a fourth resistor, a first end of which is connected to the second end of the negative switch, and a second end of which is grounded; A controller is connected to the positive switch, the negative switch, the first switch and the second switch, and includes a memory and a processor. The memory stores a computer program. When the processor executes the computer program, the DC charging pile insulation test method according to claim 1 is implemented.

3. The DC charging pile insulation test circuit according to claim 2, characterized in that: The first resistor is the same as the third resistor; the second resistor includes a first current limiting resistor and a first voltage dividing resistor, the fourth resistor includes a second current limiting resistor and a second voltage dividing resistor, the first current limiting resistor is the same as the second current limiting resistor, and the first voltage dividing resistor is the same as the second voltage dividing resistor; The first end of the first current limiting resistor is connected to the second end of the positive switch, and the second end of the first current limiting resistor is grounded through the first voltage dividing resistor; the first end of the second current limiting resistor is connected to the second end of the negative switch, and the second end of the second current limiting resistor is grounded through the second voltage dividing resistor; The controller is connected to a first common terminal and a second common terminal respectively; the first common terminal is a common terminal of the first current limiting resistor and the first voltage dividing resistor, and the second common terminal is a common terminal of the second current limiting resistor and the second voltage dividing resistor.

4. The DC charging pile insulation test circuit according to claim 3, characterized in that: The controller is connected to the first common end through a first optical coupling isolation unit, and the controller is connected to the second common end through a second optical coupling isolation unit.

5. The DC charging pile insulation test circuit according to claim 2, characterized in that: The positive switch, the negative switch, the first switch, and the second switch each include a relay.

6. A DC charging pile insulation test device, characterized in that: Used to execute the steps of the method according to claim 1, applied to a DC charging pile insulation test circuit, the DC charging pile includes a positive bus and a negative bus, and the DC charging pile insulation test circuit includes a positive switch, a negative switch, a first switch, a second switch, a first resistor, a second resistor, a third resistor, and a fourth resistor; the first end of the positive switch is connected to the positive bus; the first end of the first resistor is connected to the second end of the positive switch, and the second end of the first resistor is grounded through the first switch; the first end of the second resistor is connected to the second end of the positive switch, and the second end of the second resistor is grounded; the first end of the negative switch is connected to the negative bus; the first end of the third resistor is connected to the second end of the negative switch, and the second end of the third resistor is grounded through the second switch; the first end of the fourth resistor is connected to the second end of the negative switch, and the second end of the fourth resistor is grounded; The insulation testing device comprises: A data acquisition module, used to control the positive switch and the negative switch to be closed, and control the first switch and the second switch to be opened, so that the DC charging pile insulation test circuit enters a first state, and obtains the positive bus-to-ground voltage and the negative bus-to-ground voltage in the first state; controls the positive switch, the negative switch and the first switch to be closed, and controls the second switch to be opened, so that the DC charging pile insulation test circuit enters a second state, and obtains the positive bus-to-ground voltage and the negative bus-to-ground voltage in the second state; controls the positive switch, the negative switch and the second switch to be closed, and controls the first switch to be opened, so that the DC charging pile insulation test circuit enters a third state, and obtains the positive bus-to-ground voltage and the negative bus-to-ground voltage in the third state; A first processing module, configured to determine a positive bus-to-ground resistance based on the positive bus-to-ground voltage and the negative bus-to-ground voltage in the first state and the positive bus-to-ground voltage and the negative bus-to-ground voltage in the second state; A second processing module, used to determine the negative bus-to-ground resistance based on the positive bus-to-ground voltage and the negative bus-to-ground voltage in the first state, and the positive bus-to-ground voltage and the negative bus-to-ground voltage in the third state; The insulation performance determination module is used to determine the insulation performance of the DC charging pile based on the positive busbar-to-ground resistance and the negative busbar-to-ground resistance.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to claim 1 are implemented.

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