A charging pile insulation detection system and method

Abstract

The present application discloses a charging pile insulation detection system and method. The system uses a charging pile insulation detection circuit to perform insulation detection on the charging pile. The system includes: a bus voltage measurement module, which is used to measure the positive bus voltage to ground, the negative bus voltage to ground and the voltage between the positive and negative buses of the charging pile insulation detection circuit; an insulation resistance calculation module, which is used to calculate the positive bus insulation resistance to ground and the negative bus insulation resistance to ground in the charging pile insulation detection circuit according to the positive bus voltage to ground, the negative bus voltage to ground and the voltage between the positive and negative buses; and an insulation state determination module, which is used to determine the insulation state of the charging pile according to the positive bus insulation resistance to ground and the negative bus insulation resistance to ground. The present application solves the technical problem of insulation detection of charging modules of charging piles in related technologies.

Description

Technical Field

[0001] The present application relates to the technical field of charging pile insulation detection, and in particular, to a charging pile insulation detection system and method. Background Art

[0002] With the rapid development of charging pile charging module technology and rechargeable battery technology, the maximum voltage level of DC charging piles has increased from 750V to 1000V. The function of charging piles is similar to that of gas pumps in gas stations. They can be fixed on the ground or on the wall and installed in public buildings (public buildings, shopping malls, public parking lots, etc.) and residential parking lots or charging stations. They can charge various types of electric vehicles according to different voltage levels. However, insulation failure of charging pile charging modules may cause electric shock accidents, so insulation detection is crucial for safe charging of charging piles.

[0003] With regard to the problem of insulation detection of charging modules of charging piles in related technologies, no effective solution has been proposed yet. Summary of the invention

[0004] The main purpose of the present application is to provide a charging pile insulation detection system and method to solve the problem of insulation detection of the charging module of the charging pile in the related art.

[0005] In order to achieve the above-mentioned objectives, in a first aspect, the present application provides a charging pile insulation detection system, which uses a charging pile insulation detection circuit to perform insulation detection on the charging pile, and the system includes: a bus voltage measurement module, used to measure the positive bus voltage to ground, the negative bus voltage to ground and the voltage between the positive and negative buses of the charging pile insulation detection circuit; an insulation resistance calculation module, used to calculate the positive bus insulation resistance to ground and the negative bus insulation resistance to ground in the charging pile insulation detection circuit according to the positive bus voltage to ground, the negative bus voltage to ground and the voltage between the positive and negative buses; and an insulation state determination module, used to determine the insulation state of the charging pile according to the positive bus insulation resistance to ground and the negative bus insulation resistance to ground.

[0006] According to the charging pile insulation detection system of the present application, the system also includes: a switch control module, which is used to control the opening and closing of the switch in the charging pile insulation detection circuit, so as to enable the bus voltage measurement module to measure the positive bus voltage to the ground, the negative bus voltage to the ground and the voltage between the positive and negative buses.

[0007] According to the charging pile insulation detection system of the present application, the insulation resistance calculation module includes: a voltage judgment unit, used to judge the size of the positive bus-to-ground voltage and the size of the negative bus-to-ground voltage; and a calculation unit, used to calculate the positive bus-to-ground insulation resistance and the negative bus-to-ground insulation resistance in the charging pile insulation detection circuit based on the size of the positive bus-to-ground voltage and the size of the negative bus-to-ground voltage.

[0008] According to the charging pile insulation detection system of the present application, the insulation status determination module is also used to: select the minimum value of the positive busbar-to-ground insulation resistance and the negative busbar-to-ground insulation resistance as the insulation detection resistance value; and determine the insulation status of the charging pile according to a pre-set insulation resistance threshold and the insulation detection resistance value.

[0009] According to the charging pile insulation detection system of the present application, the insulation status judgment module is also used for: when the insulation detection resistance value is less than a preset insulation resistance lower limit value, judging that the insulation status of the charging pile is an insulation fault; when the insulation detection resistance value is greater than a preset insulation resistance lower limit value and less than the insulation resistance upper limit value, judging that the insulation status of the charging pile is an insulation alarm; and when the insulation detection resistance value is greater than the insulation resistance upper limit value, judging that the insulation status of the charging pile is good insulation; wherein the insulation resistance threshold value includes the insulation resistance lower limit value and the insulation resistance upper limit value.

[0010] In the second aspect, the present application also provides a charging pile insulation detection method, which uses a charging pile insulation detection circuit to perform insulation detection on the charging pile, and the method includes: measuring the positive bus-to-ground voltage, the negative bus-to-ground voltage and the voltage between the positive and negative buses of the charging pile insulation detection circuit; calculating the positive bus-to-ground insulation resistance and the negative bus-to-ground insulation resistance in the charging pile insulation detection circuit according to the positive bus-to-ground voltage, the negative bus-to-ground voltage and the voltage between the positive and negative buses; and determining the insulation state of the charging pile according to the positive bus-to-ground insulation resistance and the negative bus-to-ground insulation resistance.

[0011] According to the charging pile insulation detection method of the present application, the method also includes: controlling the opening and closing of the switch in the charging pile insulation detection circuit to measure the positive bus voltage to ground, the negative bus voltage to ground and the voltage between the positive and negative buses.

[0012] According to the charging pile insulation detection method of the present application, the calculation of the positive bus-to-ground insulation resistance and the negative bus-to-ground insulation resistance in the charging pile insulation detection circuit includes: judging the magnitude of the positive bus-to-ground voltage and the magnitude of the negative bus-to-ground voltage; and based on the magnitude of the positive bus-to-ground voltage and the magnitude of the negative bus-to-ground voltage, calculating the positive bus-to-ground insulation resistance and the negative bus-to-ground insulation resistance in the charging pile insulation detection circuit.

[0013] According to the charging pile insulation detection method of the present application, determining the insulation state of the charging pile based on the positive busbar-to-ground insulation resistance and the negative busbar-to-ground insulation resistance includes: selecting the minimum value of the positive busbar-to-ground insulation resistance and the negative busbar-to-ground insulation resistance as the insulation detection resistance value; and determining the insulation state of the charging pile based on a pre-set insulation resistance threshold and the insulation detection resistance value.

[0014] According to the charging pile insulation detection method of the present application, determining the insulation state of the charging pile based on the insulation resistance of the positive bus to the ground and the insulation resistance of the negative bus to the ground also includes: when the insulation detection resistance value is less than a preset insulation resistance lower limit value, determining that the insulation state of the charging pile is an insulation fault; when the insulation detection resistance value is greater than a preset insulation resistance lower limit value and less than the insulation resistance upper limit value, determining that the insulation state of the charging pile is an insulation alarm; and when the insulation detection resistance value is greater than the insulation resistance upper limit value, determining that the insulation state of the charging pile is good insulation; wherein the insulation resistance threshold value includes the insulation resistance lower limit value and the insulation resistance upper limit value.

[0015] The present application adopts a charging pile insulation detection circuit to perform insulation detection on the charging pile, and calculates the insulation resistance of the positive bus to ground and the insulation resistance of the negative bus to ground in the charging pile insulation detection circuit according to the positive bus to ground voltage, the negative bus to ground voltage and the voltage between the positive and negative buses, and determines the insulation state of the charging pile accordingly, thereby ensuring that the charging pile operates under good insulation conditions, and greatly preventing safety accidents such as electric shock caused by insulation failures, thereby ensuring the safe charging of electric vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings constituting a part of this application are used to provide a further understanding of this application, so that other features, purposes and advantages of this application become more obvious. The schematic embodiment drawings and their descriptions of this application are used to explain this application and do not constitute an improper limitation on this application. In the drawings:

[0017] Figure 1 It is a charging pile insulation detection equivalent circuit provided in accordance with an embodiment of the present application;

[0018] Figure 2is a block diagram of a charging pile insulation detection system provided according to an embodiment of the present application; and

[0019] Figure 3 It is a flow chart of a charging pile insulation detection method provided according to an embodiment of the present application. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this application.

[0021] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0022] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0023] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0024] In addition, the term "plurality" shall mean two or more.

[0025] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0026] Before specifically introducing the technical solution and principle of the present application, the charging pile insulation detection circuit used in the present application is first introduced. Figure 1 It is a charging pile insulation detection equivalent circuit provided in an embodiment of the present application. Generally speaking, the insulation detection of the charging pile needs to be performed using a charging pile insulation detection circuit. Figure 1 The equivalent circuit of the charging pile insulation detection circuit is shown in FIG. Figure 1 As shown, the voltage between the DC positive bus DC+ and the DC negative bus DC- is Vpn. By controlling the opening and closing of switches K1, K2, and K3, the voltage Vp of the positive bus DC+ to ground and the voltage Vn of the negative bus DC- to ground can be measured. Figure 1 In the figure, R1 and R2 are balanced bridge switching resistors, and R1 = R2, Rp is the insulation resistance of the positive bus DC+ to the ground, and Rn is the insulation resistance of the negative bus DC- to the ground. The charging pile insulation detection circuit and the equivalent circuit of the charging pile insulation detection circuit are both well-known technologies in the art, and their principles are not elaborated in detail here.

[0027] Figure 2 is a block diagram of a charging pile insulation detection system provided according to an embodiment of the present application, such as Figure 2 As shown, the system uses a charging pile insulation detection circuit to perform insulation detection on the charging pile. The system includes a bus voltage measurement module 10, an insulation resistance calculation module 20 and an insulation state determination module 30.

[0028] The bus voltage measurement module 10 is used to measure the positive bus voltage to ground, the negative bus voltage to ground and the voltage between the positive and negative buses of the charging pile insulation detection circuit. The positive bus voltage to ground is Figure 1 The voltage Vp of the positive bus DC+ to ground and the voltage Vp of the negative bus to ground are shown in Figure 1 The negative bus DC- is shown in the figure as the ground voltage Vn, and the positive and negative bus voltages are Figure 1 The voltage Vpn between the positive bus DC+ and the negative bus DC- shown in FIG. can be controlled by Figure 1 The positive bus-to-ground voltage Vp, the negative bus-to-ground voltage Vn and the voltage between the positive and negative buses Vpn are measured by opening and closing the control switches K1, K2 and K3 shown in FIG.

[0029] The insulation resistance calculation module 20 is used to calculate the insulation resistance of the positive busbar to ground and the insulation resistance of the negative busbar to ground in the charging pile insulation detection circuit according to the positive busbar to ground voltage, the negative busbar to ground voltage and the voltage between the positive and negative buses. The insulation resistance of the positive busbar to ground is Figure 1The insulation resistance Rp of the positive bus DC+ to ground and the insulation resistance Rp of the negative bus to ground are shown in Figure 1 The insulation resistance calculation module 20 can calculate the insulation resistance Rp of the positive bus to ground and the insulation resistance Rn of the negative bus to ground according to Vp, Vn and Vpn when the bus voltage measurement module measures the positive bus to ground voltage Vp, the negative bus to ground voltage Vn and the voltage between the positive and negative buses. Of course, those skilled in the art should understand that the insulation resistance calculation module 20 needs to combine the insulation resistance Rp and Rn in the process of calculating Rp and Rn. Figure 1 The resistance parameters (eg, balancing bridge switching resistors R1 and R2) in the equivalent circuit of the charging pile insulation detection circuit are shown.

[0030] The insulation state determination module 30 is used to determine the insulation state of the charging pile according to the insulation resistance of the positive busbar to the ground and the insulation resistance of the negative busbar to the ground. The insulation state of the charging pile is determined based on the insulation resistance. In this application, the insulation state determination module 30 determines the insulation state of the charging pile based on the insulation resistance Rp of the positive busbar to the ground and the insulation resistance Rn of the negative busbar to the ground calculated by the insulation resistance calculation module 20.

[0031] The method of measuring the positive bus-to-ground voltage, negative bus-to-ground voltage and voltage between positive and negative buses in the insulation detection circuit of the charging pile can be achieved by controlling Figure 1 The insulation detection system of the charging pile provided in the present application further includes a switch control module (not shown in the figure).

[0032] The switch control module is used to control the opening and closing of the switch in the insulation detection circuit of the charging pile, so as to enable the bus voltage measurement module 10 to measure the positive bus voltage to ground, the negative bus voltage to ground and the voltage between the positive and negative buses. Specifically, the switch control module controls the opening of switches K1, K2, and K3, and the bus voltage measurement module 10 can measure the voltage Vpn between the positive and negative buses; the switch control module controls the closing of switches K1 and K3 and controls the opening of switch K2, and the bus voltage measurement module 10 can measure the voltage Vp between the positive buses to ground; the switch control module controls the closing of switches K2 and K3 and controls the opening of switch K1, and the bus voltage measurement module 10 can measure the voltage Vn between the negative buses to ground.

[0033] Figure 2 The insulation resistance calculation module 20 shown includes a voltage judgment unit and a calculation unit. The voltage judgment unit is used to judge the magnitude of the positive bus-to-ground voltage and the magnitude of the negative bus-to-ground voltage; the calculation unit is used to calculate the positive bus-to-ground insulation resistance and the negative bus-to-ground insulation resistance in the charging pile insulation detection circuit based on the magnitude of the positive bus-to-ground voltage and the magnitude of the negative bus-to-ground voltage.

[0034] The magnitude of the positive bus voltage to ground Vp is different from that of the negative bus voltage to ground Vn, and the calculation methods of the positive bus insulation resistance Rp and the negative bus insulation resistance Rn are also different. When the positive bus voltage to ground Vp is within the preset voltage range and the negative bus voltage to ground Vn is greater than the preset voltage threshold, the first calculation method is used to calculate the positive bus insulation resistance Rp and the negative bus insulation resistance Rn; when the positive bus voltage to ground Vp is greater than the preset voltage threshold and the negative bus voltage to ground Vn is within the preset voltage range, the second calculation method is used to calculate the positive bus insulation resistance Rp and the negative bus insulation resistance Rn; when both the positive bus voltage to ground Vp and the negative bus voltage to ground Vn are greater than the preset voltage threshold, the third calculation method is used to calculate the positive bus insulation resistance Rp and the negative bus insulation resistance Rn.

[0035] The preset voltage range is generally a range close to 0 V, for example, the preset voltage range may be between -0.1 V and +0.1 V. The preset voltage threshold is generally a value much greater than 0 V, for example, the preset voltage threshold may be 10V.

[0036] Specifically, when the positive bus voltage to ground Vp is within the range of -0.1V and +0.1V and the negative bus voltage to ground Vn is greater than 10V, the first calculation method is used to calculate the positive bus insulation resistance Rp and the negative bus insulation resistance Rn. In the first calculation method, the negative bus insulation resistance Rn is approximately infinite, and the positive bus insulation resistance Rp is calculated as follows:

[0037]

[0038] In formula (1), Rp represents the insulation resistance of the positive busbar to ground; Vpn represents the voltage between the positive and negative busbars; Vn represents the voltage between the negative busbar to ground; R1 represents the switching resistance of the balancing bridge, and R1 is a known resistance value in advance. It should be understood that Figure 1 In the formula (1), R1=R2, so either R1 or R2 can be used in the calculation.

[0039] When the positive bus voltage to ground Vp is greater than 10V and the negative bus voltage to ground Vn is within the range of -0.1V and +0.1V, the second calculation method is used to calculate the positive bus insulation resistance Rp and the negative bus insulation resistance Rn. In the second calculation method, the positive bus insulation resistance Rp is approximately infinite, and the calculation method of the negative bus insulation resistance Rn is as follows:

[0040]

[0041] In formula (2), Rn represents the insulation resistance of the negative busbar to the ground; Vpn represents the voltage between the positive and negative busbars; Vp represents the voltage between the positive busbar and the ground; R1 represents the switching resistance of the balancing bridge, and R1 is a known resistance value in advance. It should be understood that Figure 1 In the formula (2), R1=R2, so either R1 or R2 can be used in the calculation.

[0042] When the positive bus voltage to ground Vp and the negative bus voltage to ground Vn are both greater than 10V, the third calculation method is used to calculate the positive bus insulation resistance Rp and the negative bus insulation resistance Rn, and the calculation method is as follows:

[0043]

[0044]

[0045] In formula (3) and formula (4), Rp represents the insulation resistance of the positive busbar to the ground; Rn represents the insulation resistance of the negative busbar to the ground; Vpn represents the voltage between the positive and negative buses; Vp represents the voltage between the positive busbar to the ground; Vn represents the voltage between the negative busbar to the ground; R1 represents the switching resistance of the balancing bridge, and R1 is a known resistance value in advance. It should be understood that Figure 1 In the formula (3) and (4), R1 = R2, so either R1 or R2 can be used in the calculation.

[0046] Figure 2 The insulation state determination module 30 shown is also used to: select the minimum value of the insulation resistance of the positive busbar to the ground and the insulation resistance of the negative busbar to the ground as the insulation detection resistance value; determine the insulation state of the charging pile according to the pre-set insulation resistance threshold and the insulation detection resistance value. After the insulation resistance Rp of the positive busbar to the ground and the insulation resistance Rn of the negative busbar to the ground are calculated by the technical solution described above, the minimum value of Rp and Rn can be selected as the insulation detection resistance value and used as the basis for determining the insulation state of the charging pile. It is easy to understand that the insulation state of the charging pile is better when the insulation detection resistance value is larger, and the insulation state of the charging pile is worse when the insulation detection resistance value is smaller. Therefore, the insulation state of the charging pile can be determined in combination with the pre-set insulation resistance threshold.

[0047] Figure 2 The insulation status determination module shown is also used for: when the insulation detection resistance value is less than a preset insulation resistance lower limit value, determining that the insulation status of the charging pile is an insulation fault; when the insulation detection resistance value is greater than a preset insulation resistance lower limit value and less than an insulation resistance upper limit value, determining that the insulation status of the charging pile is an insulation alarm; when the insulation detection resistance value is greater than the insulation resistance upper limit value, determining that the insulation status of the charging pile is good insulation; wherein the insulation resistance threshold includes an insulation resistance lower limit value and an insulation resistance upper limit value.

[0048] In order to more accurately judge the insulation status of the charging pile, the insulation resistance threshold may include a lower limit value of the insulation resistance and an upper limit value of the insulation resistance. According to national standards, the upper limit value and the lower limit value of the insulation resistance are different under different voltage levels. If the maximum charging voltage value of an electric vehicle charged on a charging pile is Vc, the lower limit value RL of the insulation resistance can be set to the detection voltage value Vc multiplied by 100Ω / V, that is, RL=(Vc*100Ω / V), and the upper limit value RH of the insulation resistance can be set to the detection voltage value Vc multiplied by 500Ω / V, that is, RH=(Vc*500Ω / V). Then, when the insulation detection resistance value is <RL (i.e., Vc*100Ω / V), it is determined to be an insulation fault, and charging should be stopped at this time; when RL (i.e., Vc*100Ω / V) < insulation detection resistance value < RH (i.e., Vc*500Ω / V), it is determined to be an insulation alarm, and charging can continue at this time, but the charging pile should be maintained; when the insulation detection resistance value is >RH (i.e., Vc*500Ω / V), it is determined to be good insulation and charging can be done with confidence.

[0049] Figure 3 is a flow chart of a charging pile insulation detection method provided in an embodiment of the present application. The method uses a charging pile insulation detection circuit to perform insulation detection on the charging pile. Figure 3 As shown, the method includes:

[0050] Step S301, measuring the positive bus voltage to ground, the negative bus voltage to ground and the voltage between the positive and negative buses of the charging pile insulation detection circuit;

[0051] Step S302, calculating the insulation resistance of the positive bus to ground and the insulation resistance of the negative bus to ground in the charging pile insulation detection circuit according to the positive bus to ground voltage, the negative bus to ground voltage and the voltage between the positive and negative buses;

[0052] Step S303, determining the insulation state of the charging pile according to the insulation resistance of the positive busbar to ground and the insulation resistance of the negative busbar to ground.

[0053] According to the charging pile insulation detection method of the present application, the method also includes: controlling the opening and closing of the switch in the charging pile insulation detection circuit to measure the positive bus voltage to ground, the negative bus voltage to ground and the voltage between the positive and negative buses.

[0054] According to the charging pile insulation detection method of the present application, calculating the insulation resistance of the positive bus to the ground and the insulation resistance of the negative bus to the ground in the insulation detection circuit of the charging pile includes: judging the magnitude of the positive bus voltage to the ground and the magnitude of the negative bus voltage to the ground; based on the magnitude of the positive bus voltage to the ground and the magnitude of the negative bus voltage to the ground, calculating the insulation resistance of the positive bus to the ground and the insulation resistance of the negative bus to the ground in the insulation detection circuit of the charging pile.

[0055] According to the charging pile insulation detection method of the present application, determining the insulation status of the charging pile based on the insulation resistance of the positive bus to the ground and the insulation resistance of the negative bus to the ground includes: selecting the minimum value of the insulation resistance of the positive bus to the ground and the insulation resistance of the negative bus to the ground as the insulation detection resistance value; determining the insulation status of the charging pile based on a pre-set insulation resistance threshold and the insulation detection resistance value.

[0056] According to the charging pile insulation detection method of the present application, determining the insulation status of the charging pile based on the insulation resistance of the positive bus to the ground and the insulation resistance of the negative bus to the ground also includes: when the insulation detection resistance value is less than a preset insulation resistance lower limit value, determining that the insulation status of the charging pile is an insulation fault; when the insulation detection resistance value is greater than a preset insulation resistance lower limit value and less than the insulation resistance upper limit value, determining that the insulation status of the charging pile is an insulation alarm; when the insulation detection resistance value is greater than the insulation resistance upper limit value, determining that the insulation status of the charging pile is good insulation; wherein the insulation resistance threshold includes the insulation resistance lower limit value and the insulation resistance upper limit value.

[0057] It should be noted that the specific details and benefits of the charging pile insulation detection method provided by the present invention are similar to those of the charging pile insulation detection system provided by the present invention, and will not be elaborated here.

[0058] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A charging pile insulation detection system, characterized in that: The system uses a charging pile insulation detection circuit to perform insulation detection on the charging pile. The system includes: A bus voltage measurement module, used to measure the positive bus voltage to ground, the negative bus voltage to ground and the voltage between the positive and negative buses of the charging pile insulation detection circuit; an insulation resistance calculation module, used to calculate the insulation resistance of the positive bus to ground and the insulation resistance of the negative bus to ground in the charging pile insulation detection circuit according to the positive bus to ground voltage, the negative bus to ground voltage and the voltage between the positive and negative buses; and An insulation state determination module, used to determine the insulation state of the charging pile according to the insulation resistance of the positive busbar to ground and the insulation resistance of the negative busbar to ground; Calculating the insulation resistance of the positive bus to ground and the insulation resistance of the negative bus to ground in the charging pile insulation detection circuit according to the positive bus to ground voltage, the negative bus to ground voltage and the voltage between the positive and negative buses, including: When the positive bus voltage to ground Vp is within the preset voltage range and the negative bus voltage to ground Vn is greater than the preset voltage threshold, the positive bus insulation resistance Rp is calculated by the following calculation method: In formula (1), Rp represents the insulation resistance of the positive busbar to the ground; Vpn represents the voltage between the positive and negative busbars; Vn represents the voltage between the negative busbar to the ground; R1 represents the switching resistance of the balancing bridge; When the positive bus voltage to ground Vp is greater than the preset voltage threshold and the negative bus voltage to ground Vn is within the preset voltage range, the negative bus insulation resistance Rn is calculated by the following calculation method: In formula (2), Rn represents the insulation resistance of the negative busbar to the ground; Vpn represents the voltage between the positive and negative busbars; Vp represents the voltage between the positive busbar and the ground; R1 represents the switching resistance of the balancing bridge; When the positive busbar-to-ground voltage Vp and the negative busbar-to-ground voltage Vn are both greater than the preset voltage threshold, the positive busbar-to-ground insulation resistance Rp and the negative busbar-to-ground insulation resistance Rn are calculated by the following calculation method: In formula (3) and formula (4), Rp represents the insulation resistance of the positive busbar to the ground; Rn represents the insulation resistance of the negative busbar to the ground; Vpn represents the voltage between the positive and negative busbars; Vp represents the voltage between the positive busbar to the ground; Vn represents the voltage between the negative busbar to the ground; R1 represents the switching resistance of the balancing bridge; The insulation state determination module is also used for: Selecting the minimum value of the insulation resistance of the positive busbar to ground and the insulation resistance of the negative busbar to ground as the insulation detection resistance value; and When the insulation detection resistance value is less than a preset insulation resistance lower limit value, determining that the insulation state of the charging pile is an insulation fault; When the insulation detection resistance value is greater than a preset insulation resistance lower limit value and less than an insulation resistance upper limit value, determining that the insulation state of the charging pile is an insulation alarm; and When the insulation detection resistance value is greater than the insulation resistance upper limit value, it is determined that the insulation state of the charging pile is good; The insulation resistance threshold includes the insulation resistance lower limit value and the insulation resistance upper limit value; the preset voltage range is between -0.1V and +0.1V, and the preset voltage threshold is 10V.

2. The charging pile insulation detection system according to claim 1, characterized in that: The system also includes: The switch control module is used to control the opening and closing of the switch in the charging pile insulation detection circuit, so that the bus voltage measurement module can measure the positive bus voltage to ground, the negative bus voltage to ground and the voltage between the positive and negative buses.

3. The charging pile insulation detection system according to claim 1, characterized in that: The insulation resistance calculation module comprises: a voltage determination unit, used to determine the magnitude of the positive bus voltage to ground and the magnitude of the negative bus voltage to ground; and A calculation unit is used to calculate the insulation resistance of the positive bus to the ground and the insulation resistance of the negative bus to the ground in the insulation detection circuit of the charging pile based on the magnitude of the positive bus to the ground voltage and the magnitude of the negative bus to the ground voltage.

4. A charging pile insulation detection method, characterized in that: The method uses a charging pile insulation detection circuit to perform insulation detection on the charging pile, and the method includes: Measuring the positive bus-to-ground voltage, the negative bus-to-ground voltage and the voltage between the positive and negative bus bars of the charging pile insulation detection circuit; Calculating the insulation resistance of the positive bus to ground and the insulation resistance of the negative bus to ground in the charging pile insulation detection circuit according to the positive bus to ground voltage, the negative bus to ground voltage and the voltage between the positive and negative buses; and Determining the insulation state of the charging pile according to the insulation resistance of the positive busbar to ground and the insulation resistance of the negative busbar to ground; Calculating the insulation resistance of the positive bus to ground and the insulation resistance of the negative bus to ground in the charging pile insulation detection circuit according to the positive bus to ground voltage, the negative bus to ground voltage and the voltage between the positive and negative buses, including: When the positive bus voltage to ground Vp is within the preset voltage range and the negative bus voltage to ground Vn is greater than the preset voltage threshold, the positive bus insulation resistance Rp is calculated by the following calculation method: In formula (1), Rp represents the insulation resistance of the positive busbar to the ground; Vpn represents the voltage between the positive and negative busbars; Vn represents the voltage between the negative busbar to the ground; R1 represents the switching resistance of the balancing bridge; When the positive bus voltage to ground Vp is greater than the preset voltage threshold and the negative bus voltage to ground Vn is within the preset voltage range, the negative bus insulation resistance Rn is calculated by the following calculation method: In formula (2), Rn represents the insulation resistance of the negative busbar to the ground; Vpn represents the voltage between the positive and negative busbars; Vp represents the voltage between the positive busbar and the ground; R1 represents the switching resistance of the balancing bridge; When the positive busbar-to-ground voltage Vp and the negative busbar-to-ground voltage Vn are both greater than the preset voltage threshold, the positive busbar-to-ground insulation resistance Rp and the negative busbar-to-ground insulation resistance Rn are calculated by the following calculation method: In formula (3) and formula (4), Rp represents the insulation resistance of the positive busbar to the ground; Rn represents the insulation resistance of the negative busbar to the ground; Vpn represents the voltage between the positive and negative busbars; Vp represents the voltage between the positive busbar to the ground; Vn represents the voltage between the negative busbar to the ground; R1 represents the switching resistance of the balancing bridge; The step of determining the insulation state of the charging pile according to the insulation resistance of the positive busbar to ground and the insulation resistance of the negative busbar to ground includes: Selecting the minimum value of the insulation resistance of the positive busbar to ground and the insulation resistance of the negative busbar to ground as the insulation detection resistance value; and When the insulation detection resistance value is less than a preset insulation resistance lower limit value, determining that the insulation state of the charging pile is an insulation fault; When the insulation detection resistance value is greater than a preset insulation resistance lower limit value and less than an insulation resistance upper limit value, determining that the insulation state of the charging pile is an insulation alarm; and When the insulation detection resistance value is greater than the insulation resistance upper limit value, it is determined that the insulation state of the charging pile is good; The insulation resistance threshold includes the insulation resistance lower limit value and the insulation resistance upper limit value; the preset voltage range is between -0.1V and +0.1V, and the preset voltage threshold is 10V.

5. The charging pile insulation detection method according to claim 4, characterized in that: The method further includes: The opening and closing of the switch in the charging pile insulation detection circuit is controlled to measure the positive bus voltage to ground, the negative bus voltage to ground and the voltage between the positive and negative buses.

6. The charging pile insulation detection method according to claim 4, characterized in that: The calculation of the insulation resistance of the positive busbar to the ground and the insulation resistance of the negative busbar to the ground in the insulation detection circuit of the charging pile includes: Determining the magnitude of the positive bus voltage to ground and the magnitude of the negative bus voltage to ground; and Based on the magnitude of the positive bus-to-ground voltage and the magnitude of the negative bus-to-ground voltage, the positive bus-to-ground insulation resistance and the negative bus-to-ground insulation resistance in the charging pile insulation detection circuit are calculated.

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