Power distribution protection circuit and double-gun direct current charging pile power distribution system applying same

Abstract

The invention provides a power distribution protection circuit and a double-gun direct current charging pile power distribution system applying the power distribution protection circuit, the power distribution protection circuit is connected between a single-chip microcomputer circuit and three contactor groups, the single-chip microcomputer circuit outputs three paths of contactor control signals, and each path of contactor control signal is coupled with one contactor group. The method is realized by using a hardware circuit without the participation of a software strategy, so that the cost is reduced and the safety is improved; the damage to the battery pack of the electric automobile caused by simultaneous opening of three groups of direct-current contactors during software misoperation can be prevented; when all outputs are disconnected through misoperation, the circuit does not affect the normal process in progress, and the user experience is better; compared with software interlocking, the method is more convenient and reliable; whether misoperation exists or not can be detected, and correction can be conducted in time.

Description

Technical Field

[0001] The present invention relates to the technical field of power distribution, and in particular to a power distribution protection circuit and a dual-gun DC charging pile power distribution system to which the same is applied. Background Art

[0002] With the gradual increase in the ownership of new energy vehicles and the gradual increase in the cruising range of pure electric vehicles, the demand for high-power charging of electric vehicles is increasing. To improve the charging speed and the utilization efficiency of charging piles, the use of flexible power distribution technology is also increasing. During the flexible power distribution process, if the distribution is incorrect, it will cause the high-voltage battery pack in the two battery packs to discharge to the low-voltage battery pack, which may cause the risk of damage to the vehicle battery.

[0003] Existing power distribution systems generally use software algorithms for interlocking or use software to control hardware interlocking. However, software algorithms are prone to the risk of software crashes, while using software to control hardware interlocking is prone to closing all output contactors when an error occurs, thereby affecting normal charging. Summary of the Invention

[0004] In view of the above-mentioned disadvantages of the prior art, the present invention provides a power distribution protection circuit and a dual-gun DC charging pile power distribution system to which the same is applied, which are used to solve the technical problem that the existing power distribution depends on software and is prone to crashes.

[0005] To achieve the above object, the present invention provides a power distribution protection circuit, which is connected between a single-chip microcomputer circuit and three contactor groups. The single-chip microcomputer circuit outputs three-way contactor control signals, and each way of contactor control signal is respectively coupled to a contactor group. The power distribution protection circuit includes:

[0006] A first AND gate, a first NAND gate, a first inverter, and a second inverter; the first-way contactor control signal output by the single-chip microcomputer circuit is connected to one input end of the first AND gate, and the other input end of the first AND gate is connected to the output end of the first NAND gate; the output end of the first AND gate is connected to the input end of the first inverter, the output end of the first inverter is connected to the input end of the second inverter, and the output end of the second inverter is connected to the first DC contactor group and its control circuit;

[0007] A second AND gate, a second NAND gate, a third inverter, and a fourth inverter; the second-way contactor control signal output by the single-chip microcomputer circuit is connected to one input end of the second AND gate, and the other input end of the second AND gate is connected to the output end of the second NAND gate; the output end of the second AND gate is connected to the input end of the third inverter, the output end of the third inverter is connected to the input end of the fourth inverter, and the output end of the fourth inverter is connected to the second DC contactor group and its control circuit;

[0008] The third AND gate, the third NAND gate, the fifth inverter, and the sixth inverter; the third contactor control signal output by the single-chip microcomputer circuit is connected to one input terminal of the third AND gate, the other input terminal of the third AND gate is connected to the output terminal of the third NAND gate, the output terminal of the third AND gate is connected to the input terminal of the fifth inverter, the output terminal of the fifth inverter is connected to the input terminal of the sixth inverter, and the output terminal of the sixth inverter is connected to the third DC contactor group and its control circuit;

[0009] Among them, the output terminal of the third AND gate is also respectively connected to one input terminal of the second NAND gate and one input terminal of the first NAND gate; the output terminal of the second AND gate is also respectively connected to one input terminal of the third NAND gate and the other input terminal of the first NAND gate; the output terminal of the first AND gate is also respectively connected to the other input terminal of the second NAND gate and the other input terminal of the third NAND gate.

[0010] In an embodiment of the present application, when the first contactor control signal and the second contactor control signal output by the single-chip microcomputer circuit are high levels and the third contactor control signal is a low level, the first DC contactor group and the second DC contactor group are closed, and the third DC contactor group is disconnected.

[0011] In an embodiment of the present application, when the first contactor control signal and the third contactor control signal output by the single-chip microcomputer circuit are high levels and the second contactor control signal is a low level, the first DC contactor group and the third DC contactor group are closed, and the second DC contactor group is disconnected.

[0012] In an embodiment of the present application, when the second contactor control signal and the third contactor control signal output by the single-chip microcomputer circuit are high levels and the first contactor control signal is a low level, the second DC contactor group and the third DC contactor group are closed, and the first DC contactor group is disconnected.

[0013] In an embodiment of the present application, when the first contactor control signal and the second contactor control signal output by the single-chip microcomputer circuit are high levels and the third contactor control signal changes from a low level to a high level, the first DC contactor group and the second DC contactor group are closed, and the third DC contactor group is disconnected.

[0014] In an embodiment of the present application, when the first contactor control signal and the third contactor control signal output by the single-chip microcomputer circuit are high levels and the second contactor control signal changes from a low level to a high level, the first DC contactor group and the third DC contactor group are closed, and the second DC contactor group is disconnected.

[0015] In an embodiment of the present application, when the second contactor control signal and the third contactor control signal output by the single-chip microcomputer circuit are high levels, and the first contactor control signal changes from a low level to a high level, the second DC contactor group and the third DC contactor group are closed, and the first DC contactor group is opened.

[0016] In an embodiment of the present application, the power distribution protection circuit further includes a fourth AND gate and a fourth NAND gate; one input terminal of the fourth AND gate is connected to the contactor control signal, and the other input terminal is connected to the contactor control signal; one input terminal of the fourth NAND gate is connected to the contactor control signal, and the other input terminal is connected to the output terminal of the fourth AND gate, and the output signal of the fourth NAND gate is input into the single-chip microcomputer circuit as a fault signal; the fault signal refers to the output signal of the fourth NAND gate being low when all three contactor control signals are 1.

[0017] To achieve the above object, the present invention provides a dual-gun DC charging pile power distribution system, including a single-chip microcomputer circuit, three contactor groups, and the above-mentioned power distribution protection circuit; the power distribution protection circuit is connected between the single-chip microcomputer circuit and the contactor coils of the three contactor groups; the contacts of the contactor groups are connected between the charging module group and the vehicle-mounted battery group.

[0018] In an embodiment of the present application, it includes: a first charging module group and a second charging module group, a first vehicle-mounted battery group and a second vehicle-mounted battery group; the contacts of the first contactor group are connected between the first charging module group and the first vehicle-mounted battery group; the contacts of the third contactor group are connected between the second charging module group and the second vehicle-mounted battery group; the contacts of the second contactor group are connected between the first charging module group and the second vehicle-mounted battery group and between the second charging module group and the first vehicle-mounted battery group.

[0019] As described above, the power distribution protection circuit and the dual-gun DC charging pile power distribution system to which the present invention relates have the following beneficial effects:

[0020] (1) This application is implemented using a hardware circuit and does not require software strategies to participate, which not only reduces costs but also improves safety.

[0021] (2) This application can prevent damage to the electric vehicle battery pack caused by the simultaneous opening of the three groups of DC contactors during software misoperation.

[0022] (3) Compared with misoperation to disconnect all outputs, this circuit does not affect the normal process in progress, and the user experience is better.

[0023] (4) This application is more convenient and reliable compared to using software interlocks.

[0024] (5) This application can detect whether there is misoperation and can correct it in time. Brief Description of the Drawings

[0025] Figure 1 It shows a schematic structural diagram of a power distribution protection circuit in an embodiment of the present invention.

[0026] Figure 2 It shows a schematic structural diagram of a power distribution system for a dual-gun DC charging pile in an embodiment of the present invention. Detailed Embodiments

[0027] The following specific embodiments illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0028] It should be noted that the structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those skilled in the art to understand and read, and are not used to limit the limited conditions under which the present invention can be implemented. Therefore, they do not have a substantial technical meaning. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed in the present invention. The following detailed description should not be considered restrictive, and the scope of the embodiments of this application is only defined by the claims of the published patent. The terms used here are only for describing specific embodiments and are not intended to limit this application. Spatially related terms, such as "upper", "lower", "left", "right", "below", "beneath", "lower part", "above", "upper part", etc., may be used in the text to facilitate the description of the relationship between one element or feature shown in the figure and another element or feature.

[0029] In the present invention, unless otherwise clearly defined and limited, terms such as "install", "connect", "couple", "fix", "hold" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] Furthermore, as used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. It should be further understood that the terms "comprising", "including" indicate the presence of the stated features, operations, elements, components, items, species, and / or groups, but do not preclude the presence, occurrence, or addition of one or more other features, operations, elements, components, items, species, and / or groups. The terms "or" and "and / or" used herein are to be construed as inclusive, or meaning any one or any combination. Thus, "A, B, or C" or "A, B, and / or C" means "any of the following: A; B; C; A and B; A and C; B and C; A, B, and C". An exception to this definition occurs only when the combination of elements, functions, or operations is inherently mutually exclusive in some manner.

[0031] To overcome the problems in the above-mentioned background art, the present invention provides a power distribution protection circuit for a DC charging pile, which is a hardware interlock circuit without software participation. Since it no longer depends on software algorithms, it effectively avoids the risk of errors or shutting down all output contactors caused by software crashes, greatly improves the reliability of the system, and does not stop the ongoing charging process.

[0032] In order to make the objectives, technical solutions, and advantages of the present invention more clearly understood, the technical solutions in the embodiments of the present invention will be further described in detail through the following embodiments in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the invention.

[0033] As Figure 1 shown, the present invention provides a power distribution protection circuit, which aims to prevent the situation where three contactor groups are simultaneously turned on during the power distribution process, thereby protecting the electrical products from the risk of discharging.

[0034] The power distribution protection circuit in this embodiment is implemented by a hardware circuit and is connected between the single-chip microcomputer circuit and three contactor groups. The single-chip microcomputer circuit outputs three-way contactor control signals, and each way of contactor control signal is respectively coupled to a contactor group. The power distribution protection circuit includes the following:

[0035] The first-way contactor control signal A output by the single-chip microcomputer circuit is connected to one input terminal 14 of the first AND gate U3C, and the other input terminal 13 is connected to the output terminal of the first NAND gate U1C. The output terminal 15 (output signal A') of the first AND gate U3C is connected to the input terminal of the first inverter U2A. The output terminal of the first inverter U2A is connected to the input terminal of the second inverter U2F. The output terminal of the second inverter U2F is connected to the first DC contactor group A and its control circuit.

[0036] The second contactor control signal B output by the single-chip microcomputer circuit is connected to one of the input terminals 7 of the second AND gate U3B, and the other input terminal 8 is connected to the output terminal of the second NAND gate U1A. The output terminal 9 (output signal B’) of the second AND gate U3B is connected to the input terminal of the third inverter U2B. The output terminal of the third inverter U2B is connected to the input terminal of the fourth inverter U2E, and the output terminal of the fourth inverter U2E is connected to the second DC contactor group B and its control circuit.

[0037] The third contactor control signal C output by the single-chip microcomputer circuit is connected to one of the input terminals 1 of the third AND gate U3A, and the other input terminal 2 is connected to the output terminal of the third NAND gate U1B. The output terminal 3 (output signal C’) of the third AND gate U3A is connected to the input terminal of the fifth inverter U2C. The output terminal of the fifth inverter U2C is connected to the input terminal of the sixth inverter U2D, and the output terminal of the sixth inverter U2D is connected to the third DC contactor group C and its control circuit.

[0038] Among them, the output terminal 3 of the third AND gate U3A is also respectively connected to one of the input terminals 10 of the second NAND gate U1A and one of the input terminals 17 of the first NAND gate U1C; the output terminal 9 of the second AND gate U3B is also respectively connected to one of the input terminals 5 of the third NAND gate U1B and the other input terminal 16 of the first NAND gate U1C; the output terminal 15 of the first AND gate U3C is also respectively connected to the other input terminal 11 of the second NAND gate U1A and the other input terminal 4 of the third NAND gate U1B.

[0039] Specifically, the contactor control signals A, B, and C output by the single-chip microcomputer circuit perform logical operations through the NAND gate U1 and the AND gate U3 to generate control signals A’, B’, and C’; the control signals A’, B’, and C’ then generate control signals A1, B1, and C1 through the inverter U2, which are used to control the closing or opening of the DC contactor groups A, B, and C.

[0040] The logical operation process of the NOT gate U1 and the AND gate U3 is as follows:

[0041] When the contactor control signals A and B are at high level and the contactor control signal C is at low level, the DC contactor groups A and B are closed and the DC contactor group C is opened. The logical relationship is shown in Table 1 below.

[0042] Table 1

[0043]

[0044] When the contactor control signals A and C are at high level and the contactor control signal B is at low level, the DC contactor groups A and C are closed and the DC contactor group B is opened. The logical relationship is shown in Table 2 below.

[0045] Table 2

[0046]

[0047]

[0048] When the contactor control signals B and C are at high level and the contactor control signal A is at low level, the DC contactor groups B and C are closed and the DC contactor group A is opened. The logical relationship is shown in Table 3 below.

[0049] Table 3

[0050]

[0051] When the contactor control signals A and B are at high level and the contactor control signal C changes from low level to high level, the DC contactor groups A and B are closed and the DC contactor group C is opened. The logical relationship is shown in Table 4 below.

[0052] Table 4

[0053]

[0054] When the contactor control signals A and C are at high level and the contactor control signal B changes from low level to high level, the DC contactor groups A and C are closed and the DC contactor group B is opened. The logical relationship is shown in Table 5 below.

[0055] Table 5

[0056]

[0057] When the contactor control signals B and C are at high level and the contactor control signal A changes from low level to high level, the DC contactor groups B and C are closed and the DC contactor group A is opened. The logical relationship is shown in Table 6 below.

[0058] Table 6

[0059]

[0060] In the embodiment of the present application, the power distribution protection circuit further includes a fourth AND gate U3D and a fourth NAND gate U1D. The input terminal 31 of the fourth AND gate U3D is connected to the contactor control signal B, and the input terminal 32 is connected to the contactor control signal A; the input terminal 34 of the fourth NAND gate U1D is connected to the contactor control signal C, the input terminal 35 is connected to the output terminal 33 of the fourth AND gate U3D, and the signal output from the output terminal 36 is input to the single-chip microcomputer circuit as a fault signal D. The fault signal D outputs a low level when the contactor control signals A, B, and C are all 1, indicating a fault. The operation logic is shown in Table 7 below.

[0061] Table 7

[0062]

[0063]

[0064] As can be seen from the above, a power distribution protection circuit provided by the present invention is implemented by a hardware circuit and no longer depends on a software algorithm. Therefore, the risk of errors or shutting down all output contactors caused by software crashes is effectively avoided. Moreover, according to the logical operations in Tables 1 to 6, the situation where three contactor groups are simultaneously turned on during the power distribution process is effectively prevented, thereby protecting the electrical products from the risk of discharging.

[0065] It is true that some existing technologies can achieve the interlock of relays by using a 2-4 encoder. However, the 2-4 encoder can only achieve the conduction of one of the four paths, that is, it can only implement the logic of one charging module corresponding to four battery packs, and cannot implement the application of multiple charging module groups corresponding to multiple battery packs. The circuit in the present application uses AND gates and NOT gates to achieve logical interlock, and the logical algorithm can be flexibly designed according to needs, and the application of multiple charging modules corresponding to multiple battery packs can be achieved. Therefore, the cost is also greatly reduced.

[0066] Furthermore, since the technical solution of using a 2-4 encoder to achieve hardware interlock can only have one valid output, if a fault detection function is to be implemented, additional logic circuits need to be added, which makes the overall circuit complex, not only the cost becomes high but also it is easy to make mistakes. The circuit in the present application uses AND gates and NOT gates to achieve simplicity, and as described above, a fault detection function can be implemented.

[0067] In addition, it is worth noting that the present invention uses two inverters to achieve the functions of enhanced driving ability and signal filtering. Although theoretically a triode can also achieve the signal inversion function, the technical solution of using a triode to achieve the signal inversion function has a complex peripheral circuit, and additional considerations need to be given to the current amplification factor of the triode, whether it is saturated and conducting, etc. Moreover, the response time of the triode is longer than that of the inverter, the response speed is slow, and the manufacturing cost and PCB area are both larger.

[0068] As Figure 2 shown, a schematic structural diagram of a power distribution system of a dual-gun DC charging pile in an embodiment of the present invention is shown. In the embodiment of the present application, the single-chip microcomputer circuit outputs three contactor control signals for controlling the coils of three DC contactors to achieve the purpose of controlling the on / off of the DC contactors. The power distribution protection circuit in the above embodiment is connected between the single-chip microcomputer circuit and the DC contactor coil.

[0069] Specifically, the contactor group 1 includes a coil K1C, a contact K1A, and a contact K1B. The contact K1A connects the positive pole of the charging module group 1 and the positive pole of the vehicle-mounted battery group 1, and the contact K1B connects the negative pole of the charging module group 1 and the negative pole of the vehicle-mounted battery group 1. The contactor group 2 includes a coil K2C, a contact K2A, and a contact K2B. The contact K2A connects the negative pole of the charging module group 1 and the negative pole of the charging module group 2, and the contact K2B connects the positive pole of the charging module group 1 and the positive pole of the charging module group 2. The contactor group 3 includes a coil K3C, a contact K3A, and a contact K2B. The contact K3A connects the positive pole of the charging module group 3 and the negative pole of the vehicle-mounted battery group 2, and the contact K3B connects the negative pole of the charging module group 3 and the negative pole of the vehicle-mounted battery group 2.

[0070] The single-chip microcomputer circuit outputs a contactor control signal A, which is connected to the MOSFET Q1 through the first AND gate U3C, the first NAND gate U1C, the first inverter U2A, and the second inverter U2F. By controlling the opening and closing of the MOSFET Q1, the energization and de-energization of the DC contactor coil K1C are controlled, and further the charging state of the charging module group 1 to the vehicle-mounted battery group 1 is controlled.

[0071] The single-chip microcomputer circuit outputs a contactor control signal B, which is connected to the MOSFET Q2 through the second AND gate U3B, the second NAND gate U1A, the third inverter U2B, and the fourth inverter U2E. By controlling the opening and closing of the MOSFET Q2, the energization and de-energization of the DC contactor coil K2C are controlled, and further the charging state of the charging module group 1 to the vehicle-mounted battery group 2 and the charging state of the charging module group 2 to the vehicle-mounted battery group 1 are controlled.

[0072] The single-chip microcomputer circuit outputs a contactor control signal C, which is connected to the MOSFET Q3 through the third AND gate U3A, the third NAND gate U1B, the fifth inverter U2C, and the sixth inverter U2D. By controlling the opening and closing of the MOSFET Q3, the energization and de-energization of the DC contactor coil K3C are controlled, and further the charging state of the charging module group 2 to the vehicle-mounted battery group 2 is controlled.

[0073] In summary, the present application provides a power distribution protection circuit and a dual-gun DC charging pile power distribution system to which it is applied. The present application is implemented by a hardware circuit and does not require software strategies to participate, which not only reduces costs but also improves safety; it can prevent damage to the electric vehicle battery group caused by the simultaneous opening of the three groups of DC contactors during software misoperation; for misoperation to disconnect all outputs, the circuit does not affect the ongoing normal process, and the user experience is better; it is more convenient and reliable compared to using software interlocks; it can detect whether there is misoperation and can correct it in time. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial utilization value.

[0074] The above embodiments are only illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A power distribution protection circuit, characterized in that, The power distribution protection circuit is connected between the single-chip microcomputer circuit and three contactor groups. The single-chip microcomputer circuit outputs three contactor control signals, and each contactor control signal is respectively coupled to a contactor group; The power distribution protection circuit includes: A first AND gate, a first NAND gate, a first inverter, and a second inverter; the first contactor control signal output by the single-chip microcomputer circuit is connected to one input terminal of the first AND gate, and the other input terminal of the first AND gate is connected to the output terminal of the first NAND gate; the output terminal of the first AND gate is connected to the input terminal of the first inverter, the output terminal of the first inverter is connected to the input terminal of the second inverter, and the output terminal of the second inverter is connected to the first DC contactor group and its control circuit; A second AND gate, a second NAND gate, a third inverter, and a fourth inverter; the second contactor control signal output by the single-chip microcomputer circuit is connected to one input terminal of the second AND gate, and the other input terminal of the second AND gate is connected to the output terminal of the second NAND gate; the output terminal of the second AND gate is connected to the input terminal of the third inverter, the output terminal of the third inverter is connected to the input terminal of the fourth inverter, and the output terminal of the fourth inverter is connected to the second DC contactor group and its control circuit; A third AND gate, a third NAND gate, a fifth inverter, and a sixth inverter; the third contactor control signal output by the single-chip microcomputer circuit is connected to one input terminal of the third AND gate, and the other input terminal of the third AND gate is connected to the output terminal of the third NAND gate. The output terminal of the third AND gate is connected to the input terminal of the fifth inverter, the output terminal of the fifth inverter is connected to the input terminal of the sixth inverter, and the output terminal of the sixth inverter is connected to the third DC contactor group and its control circuit; Wherein, the output terminal of the third AND gate is also respectively connected to one input terminal of the second NAND gate and one input terminal of the first NAND gate; the output terminal of the second AND gate is also respectively connected to one input terminal of the third NAND gate and the other input terminal of the first NAND gate; the output terminal of the first AND gate is also respectively connected to the other input terminal of the second NAND gate and the other input terminal of the third NAND gate.

2. The power distribution protection circuit according to claim 1, characterized in that When the first contactor control signal and the second contactor control signal output by the single-chip microcomputer circuit are at high level and the third contactor control signal is at low level, the first DC contactor group and the second DC contactor group are closed, and the third DC contactor group is disconnected.

3. The power distribution protection circuit according to claim 1, wherein When the first contactor control signal and the third contactor control signal output by the single-chip microcomputer circuit are at high level and the second contactor control signal is at low level, the first DC contactor group and the third DC contactor group are closed, and the second DC contactor group is disconnected.

4. The power distribution protection circuit according to claim 1, wherein When the second contactor control signal and the third contactor control signal output by the single-chip microcomputer circuit are at high level and the first contactor control signal is at low level, the second DC contactor group and the third DC contactor group are closed, and the first DC contactor group is disconnected.

5. The power distribution protection circuit according to claim 1, characterized in that When the first contactor control signal and the second contactor control signal output by the single-chip microcomputer circuit are at high level and the third contactor control signal changes from low level to high level, the first DC contactor group and the second DC contactor group are closed, and the third DC contactor group is disconnected.

6. The power distribution protection circuit according to claim 1, wherein When the first contactor control signal and the third contactor control signal output by the single-chip microcomputer circuit are at high level, and the second contactor control signal changes from low level to high level, the first DC contactor group and the third DC contactor group are closed, and the second DC contactor group is opened.

7. The power distribution protection circuit according to claim 1, characterized in that, When the second contactor control signal and the third contactor control signal output by the single-chip microcomputer circuit are at high level, and the first contactor control signal changes from low level to high level, the second DC contactor group and the third DC contactor group are closed, and the first DC contactor group is opened.

8. The power distribution protection circuit according to claim 1, characterized in that The power distribution protection circuit is further provided with a fourth AND gate and a fourth NAND gate; one input terminal of the fourth AND gate is connected to the contactor control signal, and the other input terminal is connected to the contactor control signal; one input terminal of the fourth NAND gate is connected to the contactor control signal, and the other input terminal is connected to the output terminal of the fourth AND gate, and the output signal of the fourth NAND gate is input into the single-chip microcomputer circuit as a fault signal; the fault signal refers to the output signal of the fourth NAND gate being at low level when the three contactor control signals are all 1.

9. A power distribution system for a dual-gun DC charging pile, characterized in that, It includes a single-chip microcomputer circuit, three contactor groups, and the power distribution protection circuit according to any one of claims 1 to 8; the power distribution protection circuit is connected between the single-chip microcomputer circuit and the contactor coils of the three contactor groups; the contacts of the contactor groups are connected between the charging module group and the vehicle-mounted battery group.

10. The dual-gun DC charging pile power distribution system according to claim 9, wherein, It includes: A first charging module group and a second charging module group, a first vehicle-mounted battery group and a second vehicle-mounted battery group; the contacts of the first contactor group are connected between the first charging module group and the first vehicle-mounted battery group; the contacts of the third contactor group are connected between the second charging module group and the second vehicle-mounted battery group; the contacts of the second contactor group are connected between the first charging module group and the second vehicle-mounted battery group and between the second charging module group and the first vehicle-mounted battery group.

Images