Direct current charging pile

Abstract

The application discloses a direct current charging pile comprising an alternating current power supply port used for connecting an alternating current power supply outside the direct current charging pile, and the alternating current power supply is used for providing multi-phase alternating current for the direct current charging pile; the charging module is connected with the alternating current power supply port through a multi-phase alternating current bus, and the charging module is used for converting the multi-phase alternating current into direct current so as to charge an electric vehicle; and the plurality of direct current contactors are arranged on the multi-phase alternating current bus between the charging module and the alternating current power supply port, the plurality of direct current contactors are in one-to-one correspondence with the multi-phase alternating current bus, and the plurality of direct current contactors are used for controlling the on-off of the multi-phase alternating current bus. According to the application, the on-off of the multi-phase alternating current bus is controlled through the plurality of direct current contactors, so that the layout space in the direct current charging pile is saved, and the complexity of a control circuit in the direct current charging pile and the production cost of the direct current charging pile are reduced.

Description

Technical Field

[0001] The present application relates to the technical field of charging piles, and more specifically, to a direct current charging pile. Background Art

[0002] As the main charging equipment for electric vehicles (also known as new energy vehicles), DC charging piles have become increasingly powerful with the development of charging technology. However, the dimensions of charging piles are affected by the site or other factors, and it is difficult to increase them indefinitely as the power of charging piles increases. Therefore, how to save the layout space of DC charging piles is a technical problem that needs to be solved urgently. In addition, the control circuit in the current DC charging piles is also relatively complex and costly. Summary of the invention

[0003] The embodiment of the present application provides a DC charging pile. The DC charging pile involved in the embodiment of the present application is introduced below.

[0004] In a first aspect, a DC charging pile is provided, comprising: an AC power port, used to connect an AC power supply outside the DC charging pile, the AC power supply being used to provide multi-phase AC power to the DC charging pile; a charging module, the charging module being connected to the AC power port via a multi-phase AC bus, the charging module being used to convert the multi-phase AC power into DC power to charge an electric vehicle; and a plurality of DC contactors, arranged on the multi-phase AC bus between the charging module and the AC power port, the plurality of DC contactors corresponding one-to-one to the multi-phase AC bus, and the plurality of DC contactors being used to control the on and off of the multi-phase AC bus.

[0005] As a possible implementation, the charging module also includes: an EMC filter capacitor, which is used to suppress electromagnetic interference in the internal and external environments of the DC charging pile; the DC charging pile also includes: multiple pre-charging circuits, which are arranged in parallel with the multiple DC contactors, and the multiple pre-charging circuits correspond one-to-one to the multiple DC contactors, and the multiple pre-charging circuits are used to suppress the current impact generated by the EMC filter capacitor on the multiple DC contactors.

[0006] As a possible implementation, the pre-charging circuit includes: a pre-charging resistor and a pre-charging contactor, one end of the pre-charging resistor is connected to the input end of the DC contactor, the other end of the pre-charging resistor is connected to the output end of the pre-charging contactor, and the input end of the pre-charging contactor is connected to the output end of the DC contactor to form the pre-charging circuit.

[0007] As a possible implementation manner, the resistance value of the pre-charging resistor is determined based on a voltage performance parameter of the EMC filter capacitor.

[0008] As a possible implementation, the resistance value R of the pre-charging resistor is: Wherein, t is the charging time of the pre-charging circuit, C is the capacitance of the EMC filter capacitor, and u s is the power supply voltage, U t is the real-time voltage across the pre-charge resistor.

[0009] As a possible implementation manner, the model of the pre-charging contactor is determined based on the maximum power of the pre-charging resistor.

[0010] As a possible implementation, the DC charging pile further includes: a first control circuit, which is respectively connected to the plurality of pre-charging contactors in the plurality of pre-charging circuits, and the first control circuit is used to simultaneously control the on and off of the plurality of pre-charging contactors.

[0011] As a possible implementation, the DC charging pile further includes: a second control circuit, which is respectively connected to the plurality of DC contactors, and the second control circuit is used to simultaneously control the on and off of the plurality of DC contactors.

[0012] As a possible implementation manner, the plurality of DC contactors are non-polarity DC contactors.

[0013] As a possible implementation manner, the multi-phase alternating current is three-phase alternating current.

[0014] The present application provides a DC charging pile, including: an AC power port, which is used to connect the AC power outside the DC charging pile, and the AC power is used to provide multi-phase AC power for the DC charging pile; a charging module, which is connected to the AC power port through a multi-phase AC bus, and the charging module is used to convert the multi-phase AC power into DC power to charge the electric vehicle; a plurality of DC contactors, which are arranged on the multi-phase AC bus between the charging module and the AC power port, and the plurality of DC contactors correspond to the multi-phase AC bus one by one, and the plurality of DC contactors are used to control the on and off of the multi-phase AC bus. Compared with the use of AC contactors to control the on and off of the above-mentioned multi-phase AC bus in the related art, the AC contactor is large in size, the control circuit is complex, and the cost is high. In the present application, multiple DC contactors are used to replace the AC contactor to control the on and off of the multi-phase AC bus. Since the volume of multiple DC contactors is much smaller than that of AC contactors under the same power, and the control circuit of the DC contactor is relatively simple and the cost is low, it helps to save the layout space inside the DC charging pile, reduce the complexity of the control circuit in the DC charging pile, and reduce the production cost of the DC charging pile. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of an AC contactor provided in one embodiment of the present application.

[0016] Figure 2 It is a structural schematic diagram of a DC charging pile provided in one embodiment of the present application.

[0017] Figure 3 It is a structural schematic diagram of a DC contactor provided in one embodiment of the present application.

[0018] Figure 4 It is a structural schematic diagram of a pre-charging circuit provided in one embodiment of the present application.

[0019] Figure 5 It is a structural schematic diagram of a control circuit provided in one embodiment of the present application.

[0020] Figure 6 It is a schematic diagram of the layout of replacing AC contact with a DC contactor provided in an embodiment of the present application. DETAILED DESCRIPTION

[0021] 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 embodiments of a part of the present application, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present application should fall within the scope of protection of the present application.

[0022] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0023] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention; the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance; in addition, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal connection 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.

[0024] As the main charging equipment for electric vehicles (also known as new energy vehicles), DC charging piles have become increasingly powerful with the development of charging technology. However, the dimensions of charging piles are affected by the site or other factors, and it is difficult to increase them indefinitely as the power of charging piles increases. Therefore, how to save the layout space of DC charging piles is a technical problem that needs to be solved urgently. In addition, the control circuit in the current DC charging piles is also relatively complex and costly.

[0025] In order to solve the above problems, the inventors have systematically analyzed, studied and tested the relevant technologies, and proposed solutions on this basis, which are discussed in detail as follows.

[0026] The AC contactor in the DC charging pile is an important device in the DC charging pile, which is mainly responsible for controlling the transmission and power-off of the electric energy on the AC input side to ensure the safety of the entire charging process. For example, the process of charging an electric vehicle using a DC charging pile can be: before using the DC charging pile to charge the electric vehicle, first control the AC contactor on the front-end AC circuit of the charging module (such as the AC-DC conversion module) to be attracted to power on the charging module; when the AC contactor is attracted, there is basically no current in the charging circuit, which is equivalent to being connected without load. After entering the charging process, the DC contactor on the rear-end DC circuit of the charging module is controlled to be closed to charge the electric vehicle; at the end of charging, the DC charging pile standard requires the control system to first reduce the current to below 5A, first disconnect the DC contactor on the rear-end DC circuit of the charging module, and finally disconnect the AC contactor on the front-end AC circuit of the charging module.

[0027] At present, DC charging piles need to connect 380V AC power from the power grid to the DC charging piles, and AC contactors are basically used to control the on and off of AC power transmission. As an example, taking 380V three-phase AC as an example, see Figure 1 , the size of the 750A AC contactor (such as length * width * height) is 238 * 233 * 232mm. The AC contactor will take up a large space in the DC charging pile. Secondly, the control coil of the AC contactor requires AC power supply. In the DC charging pile where the control circuit is 12VDC / 24VDC, an intermediate relay transfer is required, which not only makes the control circuit complicated, but also increases additional costs and layout difficulties; in addition, the price of AC contactors on the market is generally high.

[0028] Since the current of the AC / DC contactor in the DC charging pile is much lower than its rated current at the moment of connection and disconnection under normal operation, it is equivalent to no-load connection and no-load disconnection. Based on this working characteristic of the DC charging pile, it is possible to replace the AC contactor with multiple DC contactors to control the on and off of the AC circuit. The traditional view does not fully recognize this point, so AC contactors are usually used to control the on and off of the circuit on the AC side of the DC charging pile.

[0029] It should be understood that the embodiments of the present application are completed on the basis of the above-mentioned findings and analysis, and the above-mentioned findings and analysis are not prior art, but should be regarded as part of the contribution of the present application to the prior art.

[0030] Based on this, the present application provides a DC charging pile, including: an AC power port, used to connect the AC power outside the DC charging pile, the AC power supply is used to provide multi-phase AC power for the DC charging pile; a charging module, the charging module is connected to the AC power port through a multi-phase AC bus, the charging module is used to convert the multi-phase AC power into DC power to charge the electric vehicle; a plurality of DC contactors, arranged on the multi-phase AC bus between the charging module and the AC power port, the plurality of DC contactors correspond to the multi-phase AC bus one by one, and the plurality of DC contactors are used to control the on and off of the multi-phase AC bus. Compared with the use of AC contactors to control the on and off of the above-mentioned multi-phase AC bus in the related art, the AC contactor is large in size, the control circuit is complex, and the cost is high. In the present application, multiple DC contactors are used to replace the AC contactor to control the on and off of the multi-phase AC bus. Since the volume of multiple DC contactors is much smaller than that of AC contactors under the same power, and the control circuit of the DC contactor is relatively simple and the cost is low, it helps to save the layout space inside the DC charging pile, reduce the complexity of the control circuit in the DC charging pile, and reduce the production cost of the DC charging pile.

[0031] Combined with the following Figure 2 The DC charging pile in the embodiment of the present application is described in detail. Figure 2 As shown, the DC charging pile 200 may include an AC power port 210 , a charging module 220 and a plurality of DC contactors 230 .

[0032] The AC power port 210 can be used to connect to an AC power source outside the DC charging pile 200, and the AC power source is used to provide multi-phase AC power to the DC charging pile 200. It should be understood that the AC power port 210 is arranged inside the DC charging pile 200, and the AC power port 210 can refer to, for example, a specially designed AC power port for connecting to an external AC power source, or can refer to an input port of an AC circuit breaker (not shown in the figure) inside the DC charging pile 200. Among them, the input port of the AC circuit breaker can be connected to an external AC power source (such as an AC power grid), and the AC circuit breaker can be used to control the circuit between the AC power source and the DC charging pile 200.

[0033] In some implementations, the AC power source may refer to, for example, a power grid or an AC generator that provides AC power outside the DC charging pile 200, and this application does not make any specific limitations thereto.

[0034] The embodiment of the present application does not specifically limit the type of multi-phase AC power provided by the AC power supply, and the multi-phase AC power may be, for example, three-phase AC power (such as 380V three-phase AC power). Of course, with the development of power technology, the multi-phase AC power may also refer to four-phase AC power or even more-phase AC power.

[0035] The charging module 220 can be connected to the AC power port 210 via a multi-phase AC bus (such as a multi-phase AC copper bus), and the charging module 220 is used to convert the multi-phase AC power into DC power to charge the electric vehicle.

[0036] The charging module 220 in the embodiment of the present application may refer to an AC-DC conversion module, such as an AC-DC converter.

[0037] A plurality of DC contactors 230 are arranged on the multiphase AC busbar between the charging module 220 and the AC power port 210, and the plurality of DC contactors 230 correspond one-to-one to the multiphase AC busbar, that is, one direct contactor is arranged correspondingly on each phase AC busbar. The plurality of DC contactors 230 are used to control the on and off of the multiphase AC busbar. Among them, the multiphase AC busbar corresponds one-to-one to the multiphase AC mentioned above. That is, the number of the multiphase AC busbars corresponds to the number of phases of the AC power supply.

[0038] As an example, if the multi-phase AC power is three-phase AC power, the multi-phase AC power busbar is three AC power busbars, and the plurality of DC contactors 230 are three DC contactors. Of course, if the multi-phase AC power is four-phase AC power, the multi-phase AC power busbar is four AC power busbars, and the plurality of DC contactors 230 are four DC contactors. This application will not be elaborated here.

[0039] It should be noted that the order in which the multiple DC contactors 230 are arranged on the multi-phase AC bus is not specifically limited, and the multi-phase AC is a three-phase AC, and the three-phase AC includes three phases A, B, and C. For example, if the multiple DC contactors 230 include a first DC contactor, a second DC contactor, and a third DC contactor, for example, the first DC contactor can be arranged on the A-phase AC bus, the second DC contactor can be arranged on the B-phase AC bus, and the third DC contactor can be arranged on the C-phase AC bus; for another example, the first DC contactor can be arranged on the B-phase AC bus, the second DC contactor can be arranged on the C-phase AC bus, and the third DC contactor can be arranged on the A-phase AC bus. For another example, the first DC contactor can be arranged on the C-phase AC bus, the second DC contactor can be arranged on the A-phase AC bus, and the third DC contactor can be arranged on the B-phase AC bus.

[0040] In the embodiment of the present application, considering that the phase of the alternating current will change with time, the plurality of DC contactors 230 can be set as non-polar DC contactors, thereby helping to avoid the influence of the phase change of the alternating current on them. Of course, the plurality of DC contactors 230 can also be set as polar DC contactors, but this may be affected by the phase change of the alternating current.

[0041] In the present application, multiple DC contactors 230 are used to replace AC contactors and are arranged on a multi-phase AC busbar, so that the size of the DC charging pile 200 can be reduced. As an example, taking 380V three-phase AC as an example, see Figure 3 , the dimensions (length*width*height) of 750A DC contactor are 90*84*101.8mm. Figure 1 Compared with the AC contactor in the figure, three DC contactors with the same current level (such as 750A) are 1 / 5 of the space (volume) of the AC contactor. Therefore, using multiple DC contactors 230 to replace the AC contactor and setting them on the multi-phase AC bus can greatly reduce the layout space inside the DC charging pile 200 while ensuring the use function, thereby helping to reduce the volume of the DC charging pile 200. Secondly, the control circuit of the DC contactor only requires a DC power supply (such as 12VDC / 24VDC), and there is no need to add an intermediate relay to switch, which simplifies the complexity of the control circuit and saves additional switching costs. In addition, compared with AC contactors, the price of DC contactors is generally lower, which can further save costs.

[0042] In some implementations, the charging module 220 further includes an electromagnetic compatibility (EMC) filter capacitor, which can be used to suppress electromagnetic interference in the environment inside and outside the DC charging pile 200.

[0043] It should be noted that EMC can refer to the ability of a device or system (such as a DC charging pile 200) to work normally in its electromagnetic environment and not cause unbearable electromagnetic interference to anything in the environment. In simple terms, by setting an EMC filter capacitor, the DC charging pile 200 has the ability to resist electromagnetic interference from the internal and external environments of the DC charging pile 200.

[0044] In some implementations, the EMC filter capacitor may be disposed at the front end of the charging module 220 (i.e., the end close to the AC current input side of the charging module 220). In other words, the EMC filter capacitor may be disposed on the AC bus connected to the charging module 220.

[0045] In some implementations, the EMC filter capacitor may include an X capacitor (Cross Capacitor) and a Y capacitor (Yoke Capacitor). The X capacitor may be connected between the live wire and the neutral wire of the AC power line, or the X capacitor may be connected between the live wire and the live wire of the AC power line. The X capacitor is mainly used to reduce electromagnetic interference between lines (i.e., line-to-line noise). The Y capacitor may be connected between the live wire and the ground wire (Earth). The Y capacitor is mainly used to reduce common-mode interference from the power line to the ground wire (i.e., line-to-ground noise).

[0046] Considering that at the moment when the DC contactor is closed, the EMC filter capacitor will generate an impact current, which may cause contact damage to the DC contactor, the present application embodiment also designs a pre-charging circuit. The pre-charging circuit in the present application is described in detail below with reference to examples.

[0047] In some implementations, the DC charging pile 200 further includes a plurality of pre-charging circuits, the plurality of pre-charging circuits are arranged in parallel with the plurality of DC contactors 230, and the plurality of pre-charging circuits correspond one to one with the plurality of DC contactors 230. In other words, a pre-charging circuit is arranged in parallel at both ends of each DC contactor, and the plurality of pre-charging circuits correspond one to one with the plurality of DC contactors 230. The plurality of pre-charging circuits can be used to suppress the current impact generated by the EMC filter capacitor on the plurality of DC contactors 230.

[0048] In some implementations, see Figure 4 , each pre-charging circuit includes a pre-charging resistor and a pre-charging contactor. One end of the pre-charging resistor is connected to the input end of the DC contactor, the other end of the pre-charging resistor is connected to the output end of the pre-charging contactor, and the input end of the pre-charging contactor is connected to the output end of the DC contactor to form a pre-charging circuit. It should be noted that the DC contactor in the embodiment of the present application can also be called the main contactor of the DC charging pile 200.

[0049] The resistance value of the pre-charging resistor is determined based on the voltage performance parameter of the EMC filter capacitor. The voltage performance parameter of the EMC filter capacitor may refer to the output voltage of the EMC filter capacitor (such as the maximum output voltage of the EMC filter capacitor) when the plurality of DC contactors 230 are closed. The voltage performance parameter of the EMC filter capacitor is a voltage parameter that changes with time, and when the EMC filter capacitor is fully charged, the EMC filter capacitor has the maximum output voltage.

[0050] As an example, the resistance value R of the pre-charge resistor is:

[0051]

[0052] Where, t is the charging time of the pre-charge circuit, C is the capacitance of the EMC filter capacitor, and u s is the power supply voltage, U t It should be noted that the above power supply voltage may refer to the maximum output voltage when the EMC filter capacitor is fully charged.

[0053] In some implementations, after determining the resistance value of the pre-charging resistor, the power of the pre-charging resistor can be calculated, and then the model of the pre-charging contactor can be determined according to the maximum power of the pre-charging resistor. It should be understood that the selection of the pre-charging contactor should reserve a certain margin, for example, the rated power of the pre-charging contactor will be greater than 10% of the maximum power of the pre-charging resistor.

[0054] As an example, the instantaneous power of the pre-charge resistor is:

[0055]

[0056] Among them, P t is the instantaneous power passing through the pre-charge resistor, U t is the real-time voltage across the pre-charge resistor, and R is the resistance value of the pre-charge resistor.

[0057] It should be understood that when U t At maximum, P t That is, when U t The maximum P t is the maximum power of the pre-charge resistor.

[0058] It should be noted that the pre-charging time of the pre-charging circuit (i.e., the closing time of the pre-charging circuit) can be determined according to the voltage rise time of the EMC filter capacitor. The charging time range of the pre-charging circuit is generally 500ms to 1s. Since the resistance value of the pre-charging resistor is selected with a margin, the charging time of the pre-charging circuit is generally less than 500ms.

[0059] It should be noted that the voltage rise time of the EMC filter capacitor generally refers to the time required for the EMC filter capacitor to charge to a certain proportion, and the certain proportion may be 63.2%.

[0060] It should be noted that since the stability of the AC contactor is stronger than that of the DC contactor and can withstand the impact current generated by the EMC filter capacitor, there is usually no need to set up a pre-charging circuit.

[0061] In some implementations, the DC charging pile 200 further includes a first control circuit. The first control circuit is respectively connected to multiple pre-charging contactors in multiple pre-charging circuits, and the first control circuit is used to simultaneously control the on-off of multiple pre-charging contactors, thereby simplifying the control logic. Of course, the on-off of multiple pre-charging contactors can also be controlled one by one, and this application does not make specific restrictions on this.

[0062] In some implementations, the DC charging pile 200 also includes a second control circuit, which is respectively connected to the multiple DC contactors 230, and the second control circuit is used to simultaneously control the on and off of the multiple DC contactors 230, so that the multiple DC contactors 230 are equivalent to one AC contactor.

[0063] As an example, see Figure 5 The positive pole of the second control circuit is connected to the positive terminal R of the control coils of the multiple DC contactors 230, and the negative pole of the second control circuit is connected to the ground terminal (also called the negative terminal) B of the control coils of the multiple DC contactors 230, so that the on and off of the multiple DC contactors 230 can be controlled simultaneously by the second control circuit.

[0064] It should be understood that before controlling the closure of multiple DC contactors 230 at the same time, the pre-charge circuit should be controlled to discharge the EMC filter capacitor. That is, after controlling the closure of multiple pre-charge contactors, the discharge of the EMC filter capacitor can be achieved. After the EMC filter capacitor is discharged according to the predetermined discharge time, it is necessary to control the disconnection of multiple pre-charge contactors to disconnect the pre-charge circuit, and then, control the closure of multiple DC contactors 230 at the same time.

[0065] It should be noted that the connection method of the first control circuit is similar to the connection method of the second control circuit, and this application will not elaborate on it here.

[0066] The following describes the embodiments of the present application in more detail with reference to specific examples. Figure 6 It is only to help those skilled in the art understand the embodiments of the present application, rather than to limit the embodiments of the present application to the specific values ​​or specific scenarios illustrated. Those skilled in the art can obviously make various equivalent modifications or changes based on the examples given, and such modifications or changes also fall within the scope of the embodiments of the present application.

[0067] The following takes 380V three-phase AC as an example. Figure 6 The solution of replacing the AC contactor with multiple DC contactors in the embodiment of the present application is described in detail.

[0068] AC contactors and DC contactors are both switch control devices, such as Figure 6 As shown in the figure, the 380V AC contactor can be replaced with three DC1000V DC contactors (non-polarity), which can be installed on phases A, B, and C respectively. Before starting charging, the 12VDC control circuit in the DC charging pile can be used to control the three DC contactors to be simultaneously attracted, such as Figure 5 As shown. Based on the working characteristics of the DC charging pile's AC side being connected or disconnected without load, the use of a high-voltage DC contactor (non-polar) will basically not produce an arc when closing or disconnecting. Even if there is an arc, the load current will not be too large. The electrical life of the DC contactor is fully sufficient, and compared with the arc generated by DC power, the AC arc is easier to extinguish.

[0069] According to the above content, it can be seen that the embodiment of the present application uses three high-voltage DC contactors (non-polarity) installed on the A, B, and C phase copper bars on the AC input side, respectively, to replace the AC contactor to control the on and off of the multi-phase AC bus circuit. Since the DC contactor (non-polarity) is much smaller in height than the AC contactor of the same current level, it can be flattened in space layout, and the space height requirement is less.

[0070] In addition, the embodiment of the present application also adds a pre-charge circuit (pre-charge resistance + pre-charge relay) in parallel next to the DC contactor to prevent the EMC filter capacitor (i.e., X, Y capacitor) in the charging module from damaging the main contactor at the moment of the main contactor (i.e., three DC contactors) closing. Due to the difference in structure between the DC contactor (non-polar) and the AC contactor, the arc extinguishing method is different, and the front end of the charging module is provided with an EMC filter capacitor, which will inevitably generate an impact current when the charging module is powered on; by adding a pre-charge circuit to offset the impact of the capacitor before the main contactor is closed, the main contactor contacts are protected.

[0071] The above are only specific embodiments of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present disclosure, which should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A DC charging pile, characterized in that: include: An AC power port, used to connect an AC power source outside the DC charging pile, and the AC power source is used to provide multi-phase AC power to the DC charging pile; A charging module, the charging module is connected to the AC power port via a multi-phase AC bus, and the charging module is used to convert the multi-phase AC power into DC power to charge the electric vehicle; A plurality of DC contactors are arranged on the multi-phase AC bus between the charging module and the AC power port, the plurality of DC contactors correspond to the multi-phase AC bus one by one, and the plurality of DC contactors are used to control the on and off of the multi-phase AC bus.

2. The DC charging pile according to claim 1, characterized in that: The charging module also includes: EMC filter capacitor, used to suppress electromagnetic interference inside and outside the DC charging pile; The DC charging pile also includes: A plurality of pre-charging circuits are arranged in parallel with the plurality of DC contactors, the plurality of pre-charging circuits correspond to the plurality of DC contactors one by one, and the plurality of pre-charging circuits are used to suppress the current impact generated by the EMC filter capacitor on the plurality of DC contactors.

3. The DC charging pile according to claim 2, characterized in that: The pre-charge circuit comprises: A pre-charging resistor and a pre-charging contactor, one end of the pre-charging resistor is connected to the input end of the DC contactor, the other end of the pre-charging resistor is connected to the output end of the pre-charging contactor, and the input end of the pre-charging contactor is connected to the output end of the DC contactor to form the pre-charging circuit.

4. The DC charging pile according to claim 3, characterized in that: The resistance value of the pre-charging resistor is determined based on the voltage performance parameter of the EMC filter capacitor.

5. The DC charging pile according to claim 4, characterized in that: The resistance value R of the pre-charging resistor is: Wherein, t is the charging time of the pre-charging circuit, C is the capacitance of the EMC filter capacitor, and u s is the power supply voltage, U t is the real-time voltage across the pre-charge resistor.

6. The DC charging pile according to claim 3, characterized in that: The model of the pre-charging contactor is determined based on the maximum power of the pre-charging resistor.

7. The DC charging pile according to claim 3, characterized in that: The DC charging pile also includes: The first control circuit is respectively connected to the plurality of pre-charging contactors in the plurality of pre-charging circuits, and the first control circuit is used to simultaneously control the on and off of the plurality of pre-charging contactors.

8. The DC charging pile according to any one of claims 1 to 7, characterized in that: The DC charging pile also includes: The second control circuit is connected to the plurality of DC contactors respectively, and the second control circuit is used to control the on and off of the plurality of DC contactors simultaneously.

9. The DC charging pile according to any one of claims 1 to 7, characterized in that: The plurality of DC contactors are non-polarity DC contactors.

10. The DC charging pile according to any one of claims 1 to 7, characterized in that: The multi-phase alternating current is three-phase alternating current.

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