DC surge absorption circuit and charging pile

Abstract

The utility model discloses a DC surge absorption circuit and a charging pile comprising the DC surge absorption circuit. The charging pile comprises a plurality of charging modules and at least one set of output positive electrode cables and output negative electrode cables, and a direct current surge absorption circuit is connected between each output positive electrode cable and the corresponding output negative electrode cable. The DC surge absorption circuit is composed of a piezoresistor, an absorption capacitor, a protection resistor and a discharge resistor. The first end of the piezoresistor is connected with an output positive electrode cable of a charging pile and the first end of the protection resistor, and the second end of the piezoresistor is connected with the first end of the absorption capacitor, the first end of the discharging resistor and the second end of the protection resistor. And the second end of the absorption capacitor is connected with an output cathode cable of the charging pile and the second end of the discharge resistor. By adding a small number of common electronic components, the charging module damage caused by the output surge of the charging pile can be prevented, the reliability of the charging pile is ensured, and the circuit is exquisite in design, simple, reliable and low in cost.

Description

Technical Field

[0001] The utility model relates to the field of electric vehicles, and more specifically, to a direct current surge absorption circuit and a charging pile comprising the direct current surge absorption circuit. Background Art

[0002] As new energy vehicles become more and more popular, the demand for shortening charging time is also increasing, and the construction of DC charging piles is increasing. In order to facilitate consumers' use and the integrated management of charging modules, the distance between the current charging pile and the car battery is getting longer and longer, which leads to a longer gun line. Figure 1 This is a schematic diagram of the circuit from the existing charging pile to the car battery. Figure 1 As shown in the figure, the car battery is connected to the positive pole of the output cable of the charging pile and the positive pole of the output cable through the gun line. Since the gun line is relatively long, there will be parasitic inductance L1 and L2 on the gun line, and the car battery has certain parasitic capacitance C1 and C2. When charging starts and stops, oscillations will occur between the charging pile and the car battery to form surges. The surge voltage may exceed the anti-reverse voltage of the charging module inside the charging pile, thereby damaging the charging module. Utility Model Content

[0003] The technical problem to be solved by the utility model is that, in view of the above-mentioned defects of the prior art, a DC surge absorption circuit with sophisticated design, simple and reliable circuit and low cost is provided, and a charging pile including the DC surge absorption circuit can prevent damage to the charging module caused by the output surge of the charging pile, ensure the reliability of the charging pile, and reduce the operation and maintenance cost of the charging pile.

[0004] The technical solution adopted by the utility model to solve its technical problem is: constructing a DC surge absorption circuit, including a varistor, an absorption capacitor module and a discharge module, the first end of the varistor is connected to the output positive cable of the charging pile, the second end is connected to the first end of the absorption capacitor module and the first end of the discharge module, and the second end of the absorption capacitor module is connected to the output negative cable of the charging pile and the second end of the discharge module.

[0005] In the DC surge absorption circuit described in the utility model, the pressure-sensitive device includes a pressure-sensitive resistor, the absorption capacitor module includes at least one absorption capacitor, and the discharge module includes at least one resistor.

[0006] The DC surge absorption circuit of the present invention further comprises a protection module connected to both ends of the varistor, and the protection module comprises at least one resistor.

[0007] In the DC surge absorption circuit described in the utility model, the discharge module includes a chip resistor, and the protection module includes a cement resistor.

[0008] In the DC surge absorption circuit described in the utility model, the discharge module includes a plurality of resistors connected in series or in parallel; the protection module includes a plurality of resistors connected in series or in parallel.

[0009] Another technical solution adopted by the utility model to solve its technical problem is to construct a DC surge absorption circuit, which is composed of a varistor, an absorption capacitor, a protection resistor and a discharge resistor; the first end of the varistor is connected to the output positive cable of the charging pile and the first end of the protection resistor, the second end is connected to the first end of the absorption capacitor, the first end of the discharge resistor and the second end of the protection resistor, and the second end of the absorption capacitor is connected to the output negative cable of the charging pile and the second end of the discharge resistor.

[0010] In the DC surge absorption circuit described in the utility model, the discharge resistor is a chip resistor, and the protection resistor is a cement resistor.

[0011] Another technical solution adopted by the utility model to solve its technical problems is to construct a charging pile, including multiple charging modules and at least one group of output positive cables and output negative cables, each group of the output positive cables and the output negative cables are respectively connected with a DC surge absorption circuit; the DC surge absorption circuit includes a varistor, an absorption capacitor module, a discharge module and a protection module; the first end of the varistor is connected to the output positive cable, the second end is connected to the first end of the absorption capacitor module and the first end of the discharge module, the second end of the absorption capacitor module is connected to the output negative cable and the second end of the discharge module; the protection module is connected to both ends of the varistor.

[0012] Another technical solution adopted by the utility model to solve its technical problem is to construct a charging pile, including multiple charging modules and at least one group of output positive cables and output negative cables, each group of the output positive cables and the output negative cables are respectively connected with a DC surge absorption circuit; the DC surge absorption circuit is composed of a varistor, an absorption capacitor, a protection resistor and a discharge resistor; the first end of the varistor is connected to the output positive cable of the charging pile and the first end of the protection resistor, the second end is connected to the first end of the absorption capacitor, the first end of the discharge resistor and the second end of the protection resistor, and the second end of the absorption capacitor is connected to the output negative cable of the charging pile and the second end of the discharge resistor.

[0013] In the charging pile described in the utility model, the discharge resistor is a chip resistor, and the protection resistor is a cement resistor.

[0014] By implementing the DC surge absorption circuit of the utility model and the charging pile including the DC surge absorption circuit, by adding a DC surge absorption circuit composed of a small number of common electronic components between the output positive cable and the negative cable of the charging pile, it is possible to prevent the charging module from being damaged due to the output surge of the charging pile, thereby ensuring the reliability of the charging pile. The circuit design is sophisticated, simple, reliable and low-cost, thereby reducing the operation and maintenance cost of the charging pile. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0016] Figure 1 It is a schematic diagram of the circuit from the charging pile to the car battery in the existing design;

[0017] Figure 2 This is a principle block diagram of the DC surge absorption circuit of the utility model;

[0018] Figure 3 It is a circuit diagram of a preferred embodiment of the DC surge absorption circuit of the utility model;

[0019] Figure 4 It is a circuit diagram of another preferred embodiment of the DC surge absorption circuit of the utility model;

[0020] Figure 5 It is a circuit schematic diagram of a preferred embodiment of the charging pile of the utility model. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0022] Figure 2 FIG. 1 is a circuit diagram of a preferred embodiment of the DC surge absorption circuit of the utility model. Figure 2 As shown, a DC surge absorption circuit of the utility model includes a varistor 10, an absorption capacitor module 20 and a discharge module 30. The first end of the varistor 10 is connected to the output positive cable DC+ of the charging pile, the second end is connected to the first end of the absorption capacitor module 20 and the first end of the discharge module 30, and the second end of the absorption capacitor module 20 is connected to the output negative cable DC- of the charging pile and the second end of the discharge module 30.

[0023] Combination Figure 1-2It can be seen that the car battery is connected to the positive pole of the output cable of the charging pile and the positive pole of the output cable through the gun line. Since the gun line is relatively long, there will be parasitic inductance L1 and L2 on the gun line, and the car battery has certain parasitic capacitance C1 and C2. At this time, we connect the output positive cable DC+ and the output negative cable DC- of the charging pile. Figure 2 The DC surge absorption circuit shown in the figure includes a voltage-sensitive device 10 , an absorption capacitor module 20 and a discharge module 30 .

[0024] When the output voltage of the charging pile does not exceed the rated amplitude (e.g. 1000Vdc), the varistor 10 is in the disconnected state, at which time the discharge module 30 can discharge the absorption capacitor module 20. When the output voltage of the charging pile exceeds the rated amplitude (e.g. 1000Vdc), that is, when the charging pile is started or shut down, the parasitic inductance L1, L2 on the gun line and the battery parasitic C1, C2 oscillate to form a surge, and the surge voltage exceeds 1000Vdc. At this time, the varistor 10 is in the on state, and the surge voltage charges the absorption capacitor module 20, reducing the surge and limiting the output voltage to 1000V, protecting the power module inside the charging pile and the battery being charged.

[0025] In a preferred embodiment of the present invention, the pressure-sensitive device 10 includes a pressure-sensitive resistor, the absorption capacitor module 20 includes at least one absorption capacitor, and the discharge module 30 includes at least one resistor.

[0026] In a preferred embodiment of the present invention, the pressure-sensitive device 10 includes a pressure-sensitive switch, the absorption capacitor module 20 includes at least one absorption capacitor, and the discharge module 30 includes a plurality of series-connected, parallel-connected, or series-parallel-connected resistors.

[0027] Figure 3 FIG. 1 is a circuit diagram of a preferred embodiment of the DC surge absorption circuit of the utility model. Figure 3 As shown, a DC surge absorption circuit of the utility model includes a varistor R3, an absorption capacitor C3 and a discharge resistor R2. The first end of the varistor R3 is connected to the output positive cable DC+ of the charging pile, the second end is connected to the first end of the absorption capacitor C3 and the first end of the discharge resistor R2, and the second end of the absorption capacitor C3 is connected to the output negative cable DC- of the charging pile and the second end of the discharge resistor R2.

[0028] In this preferred embodiment, the varistor R3 can be selected as a varistor of the S20K385 model, for example. When the output voltage of the charging pile does not exceed the rated amplitude (for example, 1000Vdc), its resistance is too large, causing the circuit to be in a disconnected state. At this time, the discharge resistor R2 can discharge the absorption capacitor C3. When the output voltage of the charging pile exceeds the rated amplitude (for example, 1000Vdc), that is, when the charging pile is started or shut down, the parasitic inductance L1, L2 on the gun line and the battery parasitic C1, C2 oscillate to form a surge, and the surge voltage exceeds 1000Vdc. At this time, the varistor R3 is in the on state, and the surge voltage charges the absorption capacitor C3, reducing the surge, so that the output voltage is limited to 1000V, protecting the power module inside the charging pile, and the battery being charged.

[0029] In a preferred embodiment of the present invention, the discharge resistor R2 is preferably a chip resistor, such as a high-power high-resistance chip resistor. Of course, in other preferred embodiments of the present invention, the discharge resistor R2 can also be replaced by multiple resistors connected in series or in parallel.

[0030] Figure 4 FIG. 1 is a circuit diagram of another preferred embodiment of the DC surge absorption circuit of the utility model. Figure 4 As shown, the DC surge absorption circuit is composed of a varistor R3, an absorption capacitor C3, a protection resistor R1 and a discharge resistor R2; the first end of the varistor R3 is connected to the output positive cable DC+ of the charging pile and the first end of the protection resistor R1, the second end is connected to the first end of the absorption capacitor C3, the first end of the discharge resistor R2 and the second end of the protection resistor R1, and the second end of the absorption capacitor C3 is connected to the output negative cable DC- of the charging pile and the second end of the discharge resistor R2.

[0031] In this preferred embodiment, the varistor R3 can be a varistor of model S20K385, for example. The discharge resistor R2 is a chip resistor, for example, a high-power high-resistance chip resistor. The protection resistor R1 is a cement resistor, for example, a 10-ohm impact-resistant cement resistor.

[0032] Here, the varistor R3 and the absorption capacitor C3 can be determined according to the actual required limiting voltage. In this application, the common DC charging pile 1000V DC surge absorption circuit is used as an example for explanation. The parameters of the varistor and the absorption capacitor can be changed to make the limiting voltage greater than 1000V, such as 2000V, which all fall within the protection scope of the present utility model.

[0033] In this preferred embodiment, due to the addition of the protective resistor R1, the varistor R3 can be protected, thereby increasing its service life. Of course, in the simplified embodiment of the utility model, Figure 2-3In the embodiment shown, the protective resistor R1 can be omitted without considering the life of the varistor R3. Similarly, in other preferred embodiments of the present invention, the discharge resistor R2 and the protective resistor can be replaced by multiple resistors connected in series or in parallel.

[0034] The DC surge absorption circuit of the utility model is implemented by adding a DC surge absorption circuit composed of a small number of common electronic components between the output positive cable and the negative cable of the charging pile, thereby preventing damage to the charging module caused by the output surge of the charging pile and ensuring the reliability of the charging pile. The circuit design is sophisticated, simple, reliable and low-cost, thereby reducing the operation and maintenance costs of the charging pile.

[0035] Figure 5 This is a circuit diagram of a preferred embodiment of the charging pile of the utility model. Figure 5 As shown, the charging pile includes multiple charging modules and two groups of output positive cables DC+ and output negative cables DC-, and a DC surge absorption circuit is connected between each group of output positive cables DC+ and output negative cables DC-. Figure 5 In the preferred embodiment shown, two DC surge absorption circuits are included, one of which is composed of a varistor R3, an absorption capacitor C3, a protective resistor R1 and a discharge resistor R2; the first end of the varistor R3 is connected to the output positive cable DC+ of the charging pile and the first end of the protection resistor R1, the second end is connected to the first end of the absorption capacitor C3, the first end of the discharge resistor R2 and the second end of the protection resistor R1, and the second end of the absorption capacitor C3 is connected to the output negative cable DC- of the charging pile and the second end of the discharge resistor R2. Similarly, another DC surge absorption circuit is composed of a varistor R6, an absorption capacitor C4, a protective resistor R4 and a discharge resistor R5; the first end of the varistor R6 is connected to the output positive cable DC+ of the charging pile and the first end of the protection resistor R4, the second end is connected to the first end of the absorption capacitor C4, the first end of the discharge resistor R5 and the second end of the protection resistor R4, and the second end of the absorption capacitor C4 is connected to the output negative cable DC- of the charging pile and the second end of the discharge resistor R5.

[0036] In this preferred embodiment, the varistors R3 and R6 can be selected from the varistors of the S20K385 model, for example. When the output voltage of the charging pile does not exceed the rated amplitude (e.g., 1000Vdc), the resistance is too large, causing the circuit to be in a disconnected state. At this time, the discharge resistors R2 and R5 can discharge the absorption capacitor C3. The protective resistors R1 and R4 protect the life of the varistors R3 and R6 respectively. When the output voltage of the charging pile exceeds the rated amplitude (e.g., 1000Vdc), that is, when the charging pile is started or shut down, the parasitic inductance L1, L2 on the gun line and the battery parasitic C1, C2 oscillate to form a surge, and the surge voltage exceeds 1000Vdc. At this time, the varistors R3 and R6 are in the on state, and the surge voltage charges the absorption capacitors C3 and C4, reducing the surge, so that the output voltage is limited to 1000V, protecting the power module inside the charging pile, and the battery being charged.

[0037] In other preferred embodiments of the present invention, it is also possible to Figure 2-4 Any suitable DC surge absorption circuit disclosed in the corresponding specific embodiment can constitute the DC surge absorption circuit in the aforementioned charging pile. The rest of the charging pile can adopt the design in the prior art, which will not be described here.

[0038] By implementing the charging pile of the utility model, a DC surge absorption circuit composed of a small number of common electronic components is added between the output positive cable and the negative cable of the charging pile, thereby preventing damage to the charging module caused by the output surge of the charging pile and ensuring the reliability of the charging pile. The circuit design is sophisticated, simple, reliable and low-cost, thereby reducing the operation and maintenance cost of the charging pile.

[0039] Although the present invention is described through specific embodiments, it should be understood by those skilled in the art that various changes and equivalent substitutions may be made to the present invention without departing from the scope of the present invention. In addition, various modifications may be made to the present invention for specific situations or materials without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed, but should include all implementation methods that fall within the scope of the claims of the present invention.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A DC surge absorption circuit, characterized in that: It includes a pressure-sensitive device, an absorption capacitor module and a discharge module; the first end of the pressure-sensitive device is connected to the output positive cable of the charging pile, the second end is connected to the first end of the absorption capacitor module and the first end of the discharge module, and the second end of the absorption capacitor module is connected to the output negative cable of the charging pile and the second end of the discharge module.

2. The DC surge absorption circuit according to claim 1, characterized in that: The varistor comprises a varistor, the absorption capacitor module comprises at least one absorption capacitor, and the discharge module comprises at least one resistor.

3. The DC surge absorption circuit according to claim 2, characterized in that: It further includes a protection module connected to both ends of the varistor, and the protection module includes at least one resistor.

4. The DC surge absorption circuit according to claim 3, characterized in that: The discharge module includes a chip resistor, and the protection module includes a cement resistor.

5. The DC surge absorption circuit according to claim 3, characterized in that: The discharge module includes a plurality of resistors connected in series or in parallel; the protection module includes a plurality of resistors connected in series or in parallel.

6. A DC surge absorption circuit, characterized in that: It is composed of a varistor, an absorption capacitor, a protection resistor and a discharge resistor; the first end of the varistor is connected to the output positive cable of the charging pile and the first end of the protection resistor, the second end is connected to the first end of the absorption capacitor, the first end of the discharge resistor and the second end of the protection resistor, and the second end of the absorption capacitor is connected to the output negative cable of the charging pile and the second end of the discharge resistor.

7. The DC surge absorption circuit according to claim 6, characterized in that: The discharge resistor is a chip resistor, and the protection resistor is a cement resistor.

8. A charging pile, comprising a plurality of charging modules and at least one set of output positive cables and output negative cables, characterized in that: A DC surge absorption circuit is respectively connected between each group of the output positive cables and the output negative cables; the DC surge absorption circuit includes a varistor, an absorption capacitor module, a discharge module and a protection module; the first end of the varistor is connected to the output positive cable, the second end is connected to the first end of the absorption capacitor module and the first end of the discharge module, the second end of the absorption capacitor module is connected to the output negative cable and the second end of the discharge module; the protection module is connected to both ends of the varistor.

9. A charging pile, comprising a plurality of charging modules and at least one set of output positive cables and output negative cables, characterized in that: A DC surge absorption circuit is respectively connected between each group of the output positive cables and the output negative cables; the DC surge absorption circuit is composed of a varistor, an absorption capacitor, a protection resistor and a discharge resistor; the first end of the varistor is connected to the output positive cable of the charging pile and the first end of the protection resistor, the second end is connected to the first end of the absorption capacitor, the first end of the discharge resistor and the second end of the protection resistor, and the second end of the absorption capacitor is connected to the output negative cable of the charging pile and the second end of the discharge resistor.

10. The charging pile according to claim 9, characterized in that: The discharge resistor is a chip resistor, and the protection resistor is a cement resistor.

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