Direct current bidirectional charging pile with built-in integrated direct current electric energy meter

Abstract

The application relates to a direct-current bidirectional charging pile with a built-in integrated direct-current electric energy meter. The integrated direct-current electric energy meter is connected in series in a direct-current bus loop, and the access state of a charging module and an inverter module is controlled by switching a direct-current contactor group, so that bidirectional energy transmission of alternating current and direct current in a single device is realized. The scheme uses a fully-enclosed metering unit to replace a traditional bare shunt, effectively eliminates the hidden dangers of wiring heating and signal tampering, and improves the safety and accuracy of trade settlement. Meanwhile, based on the compact electrical topology of the shared direct-current bus, the space layout in the pile is optimized, and the system wiring complexity and equipment maintenance cost are reduced.

Description

Technical Field

[0001] This application relates to the field of new energy vehicle charging facilities technology, and in particular to a DC bidirectional charging pile with a built-in integrated DC energy meter. Background Technology

[0002] The new energy vehicle industry has entered a phase of explosive growth. As the most important supporting infrastructure for new energy vehicles, the construction speed and technological level of DC charging piles directly affect users' charging experience and the industry's development. Existing DC charging piles have shortcomings in terms of energy metering and structural integration: Poor metering security: Traditional solutions use a split structure of shunt and external meter. The shunt is usually unencapsulated and exposed, which is prone to overheating and poses a safety hazard due to contact. At the same time, the sampling signal is easily tampered with, leading to trade settlement disputes that are difficult to define.

[0003] Low integration and large size: The shunt and meter are bulky, occupying valuable space inside the pile, which makes structural design difficult and wiring complicated.

[0004] High maintenance costs: The verification and sealing process of traditional metrology systems is time-consuming, labor-intensive, and expensive. Utility Model Content

[0005] To address the aforementioned issues, this application provides a highly integrated DC bidirectional charging pile with a built-in DC energy meter.

[0006] To achieve the above objectives, this application designs a DC bidirectional charging pile with a built-in integrated DC energy meter, comprising a DC bidirectional charging pile body, wherein the DC bidirectional charging pile body internally includes: an AC input circuit; a charging module, the AC input terminal of which is connected to the AC input circuit, and the DC output terminal of which is connected to a DC bus, the DC bus including a positive bus and a negative bus; a first DC contactor group, including a first contactor connected in series on the positive bus and a second contactor connected in series on the negative bus; a charging gun interface, the positive bus being connected to the positive terminal of the charging gun interface via the first contactor, and the negative bus being connected to the negative terminal of the charging gun interface via the second contactor; an integrated DC energy meter, the current sampling unit of which is connected in series in the circuit between the second contactor and the negative terminal of the charging gun interface, the voltage sampling terminal of which is connected to the positive and negative circuits of the charging gun interface respectively; and an inverter module, the input terminal of which is connected to the DC bus via the second DC contactor group, and the output terminal of which is used to connect to an AC load.

[0007] Preferably, the second DC contactor group includes a third contactor and a fourth contactor; one end of the third contactor is connected to the node of the positive bus located at the front end of the first contactor, and the other end is connected to the positive input terminal of the inverter module; one end of the fourth contactor is connected to the node of the negative bus located at the front end of the second contactor, and the other end is connected to the negative input terminal of the inverter module.

[0008] Preferably, a DC fuse is further provided between the DC output terminal of the charging module and the first DC contactor group, and the DC fuse is connected in series on the positive bus.

[0009] Preferably, the AC input circuit includes a surge protector and a circuit breaker connected in sequence; the surge protector is connected in parallel to the mains input terminal, and the circuit breaker is connected in series between the mains input terminal and the charging module.

[0010] Preferably, it further includes an auxiliary power supply circuit and a control unit; the auxiliary power supply circuit includes a miniature leakage current switch and a switching power supply, the input terminal of the miniature leakage current switch is connected to the AC input circuit, and the output terminal is connected to the switching power supply, the switching power supply is used to output low-voltage DC power; the control unit includes a main control unit, a billing control unit and an insulation monitoring unit, the working power interface of the main control unit, the billing control unit, the insulation monitoring unit and the integrated DC energy meter are all connected to the output terminal of the switching power supply.

[0011] Preferably, the control output terminal of the main control unit is connected to the coils of the first contactor, the second contactor, the third contactor, and the fourth contactor via a control circuit, for controlling the engagement and disengagement of each contactor; the detection terminal of the insulation monitoring unit is connected to the DC high-voltage circuit at the rear end of the first DC contactor group.

[0012] The DC bidirectional charging pile with an integrated DC energy meter designed in this application achieves bidirectional AC / DC energy transmission within a single device by connecting the integrated DC energy meter in series in the DC bus circuit and using a DC contactor group to control the connection status of the charging module and the inverter module. This solution replaces the traditional exposed shunt with a fully enclosed metering unit, effectively eliminating the risks of wiring overheating and signal tampering, thus improving the security and accuracy of trade settlement. Simultaneously, the compact electrical topology based on a shared DC bus optimizes the internal space layout of the charging pile, reducing system wiring complexity and equipment maintenance costs. Attached Figure Description

[0013] Figure 1 This is an electrical principle topology diagram of a DC bidirectional charging pile with a built-in integrated DC energy meter in this embodiment of the present invention.

[0014] Figure 2This is a schematic diagram of the auxiliary power supply circuit and low-voltage control circuit in an embodiment of this utility model. Detailed Implementation

[0015] The preferred embodiments of this application are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit this application.

[0016] like Figure 1 As shown in the figure, the DC bidirectional charging pile with a built-in integrated DC energy meter described in this embodiment mainly consists of a main body. This main body integrates an AC input circuit, a charging module MK, a first DC contactor group, a charging gun interface, an integrated DC energy meter, and an inverter module INV. It aims to achieve bidirectional AC / DC energy transmission and high-precision energy metering within a single device.

[0017] Specifically, an AC input circuit is provided at the input terminal of the main power circuit. For example... Figure 1 As shown, the mains input terminal includes L, N, and PE lines connected to the charging terminal. To ensure electrical safety at the input terminal, a surge protector (SPD) and a circuit breaker (QF) are installed in the AC input circuit. Specifically, the surge protector (SPD) is connected in parallel at the mains input terminal to absorb high-voltage spikes generated by lightning strikes or power grid surges; the circuit breaker (QF) is connected in series between the mains input terminal and the charging module (MK) at the downstream end, providing overload and short-circuit protection.

[0018] The output terminal of the AC input circuit is connected to the AC input terminal of the charging module MK. In this embodiment, the charging module MK is the core power conversion unit (AC / DC), which converts the input AC power into high-voltage DC power and outputs it to the DC bus through its DC output terminal. The DC bus includes a positive bus (DC+) and a negative bus (DC-).

[0019] In some embodiments, to protect the downstream DC circuit, a DC fuse FU is provided between the DC output terminal of the charging module MK and the subsequent contactor group. In this embodiment, the DC fuse FU is connected in series on the positive bus. When a severe short circuit occurs on the DC side, the fuse FU can quickly cut off the circuit, protecting the charging module and the front-end power grid.

[0020] The energy transmission of the DC bus is divided into two main branches, one of which is a charging output branch used to connect to electric vehicles. This branch is controlled by a first DC contactor group. In this embodiment, the first DC contactor group includes a first contactor K1 and a second contactor K2.

[0021] Positive path: The positive busbar is connected to the positive terminal (DC750V+) of the charging gun interface via the first contactor K1.

[0022] Negative path: The negative busbar is connected to the negative terminal (DC750V-) of the charging gun interface via the second contactor K2.

[0023] By controlling the engagement and disengagement of the first contactor K1 and the second contactor K2, the on / off control of the charging gun interface and the DC bus can be achieved.

[0024] To achieve high security and high integration in metering, this embodiment directly embeds an integrated DC energy meter into the DC main circuit. Unlike traditional external shunt converters, this integrated DC energy meter adopts a fully enclosed design and can use commercially available mature products. Specifically: Current sampling: Its current sampling unit is directly connected in series in the circuit between the second contactor K2 and the negative terminal of the charging gun interface. This means that the energy meter can only measure the current when the second contactor K2 is closed and the current flows to the charging gun, ensuring the accuracy of the measurement.

[0025] Voltage sampling: The voltage sampling terminal of the integrated DC energy meter is connected to the positive and negative circuits of the charging gun interface to obtain the real-time charging voltage.

[0026] This connection method not only saves installation space, but also, because it is located at the rear of the contactor, it can accurately measure the actual electrical energy charged into the vehicle, avoiding standby losses from being included in the user's bill.

[0027] like Figure 1 As shown, another branch of the DC bus is used to implement the inverter function (V2L), which is specifically implemented through the inverter module INV and the second DC contactor group. In this embodiment, the second DC contactor group includes the third contactor K3 and the fourth contactor K4.

[0028] Positive power take-off point: One end of the third contactor K3 is connected to the node of the positive bus located at the front end of the first contactor K1, that is, the K1 input terminal, and the other end is connected to the positive input terminal VI+ of the inverter module INV; Negative power take-off point: One end of the fourth contactor K4 is connected to the node of the negative bus located at the front end of the second contactor K2, that is, the K2 input terminal, and the other end is connected to the negative input terminal VI- of the inverter module INV.

[0029] Inverter Output: The output terminals (VO+ / VO-) of the inverter module INV are used to connect to 220V AC load devices.

[0030] This topology allows the inverter circuit and the charging circuit to be physically connected in parallel to the DC bus, but the operating modes can be flexibly switched through the interlocking or independent control of the first contactor K1 / second contactor K2 and the third contactor K3 / fourth contactor K4.

[0031] like Figure 1 , Figure 2 As shown, in order to power the electronic units inside the pile, the system also includes an auxiliary power supply circuit. This circuit includes a miniature leakage current switch FK and a switching power supply. The input terminal of the miniature leakage current switch FK draws power from the AC input circuit, and its output terminal is connected to the switching power supply. The switching power supply converts the AC power into stable low-voltage DC power, such as 12VDC.

[0032] In some embodiments, intelligent control of the system is implemented by a control unit, which mainly includes a main control unit, a billing control unit, and an insulation monitoring unit. Specifically: Power supply: The working power interface of the main control unit, billing control unit, insulation monitoring unit and the aforementioned integrated DC energy meter are all connected to the low-voltage DC output terminal of the switching power supply to realize low-voltage power supply.

[0033] Control logic: such as Figure 2 As shown, the control output terminal of the main control unit is connected to the coils of the first contactor K1, the second contactor K2, the third contactor K3, and the fourth contactor K4 through a control loop (I / O port or drive circuit). The main control unit controls the engagement and disengagement of each contactor according to user instructions or BMS requests. For example, in charging mode, the first contactor K1 and the second contactor K2 are closed, and the third contactor K3 and the fourth contactor K4 are open; in inverter mode, the third contactor K3 and the fourth contactor K4 are closed, and the first contactor K1 and the second contactor K2 are open.

[0034] Insulation monitoring: The detection terminal of the insulation monitoring unit is connected to the DC high-voltage circuit at the rear end of the first DC contactor group to monitor the insulation resistance of the positive and negative busbars to ground in real time, ensuring personal safety.

[0035] The DC bidirectional charging pile with a built-in integrated DC energy meter provided in this application embodiment achieves bidirectional AC / DC energy transmission within a single device by connecting the integrated DC energy meter in series in the DC bus circuit and using a DC contactor group to control the connection status of the charging module and the inverter module. This solution replaces the traditional exposed shunt with a fully enclosed metering unit, effectively eliminating the risks of wiring overheating and signal tampering, thus improving the security and accuracy of trade settlement. Simultaneously, the compact electrical topology based on a shared DC bus optimizes the internal space layout of the charging pile, reducing system wiring complexity and equipment maintenance costs.

[0036] In the description of this application, it should be noted that the terms "vertical", "up", "down", "horizontal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0037] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0038] Finally, it should be noted that the above descriptions are merely preferred embodiments of this application and are not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A direct current bidirectional charging pile with a built-in integrated direct current electric energy meter, comprising a direct current bidirectional charging pile main body, characterized in that, The main body of the DC bidirectional charging pile is internally equipped with: an AC input circuit; a charging module, the AC input terminal of which is connected to the AC input circuit, and the DC output terminal of which is connected to a DC bus, the DC bus including a positive bus and a negative bus; a first DC contactor group, including a first contactor connected in series on the positive bus and a second contactor connected in series on the negative bus; a charging gun interface, the positive bus being connected to the positive terminal of the charging gun interface via the first contactor, and the negative bus being connected to the negative terminal of the charging gun interface via the second contactor; an integrated DC energy meter, the current sampling unit of which is connected in series in the circuit between the second contactor and the negative terminal of the charging gun interface, the voltage sampling terminal of which is connected to the positive and negative circuits of the charging gun interface respectively; and an inverter module, the input terminal of which is connected to the DC bus via the second DC contactor group, and the output terminal of which is used to connect to an AC load.

2. The direct current bidirectional charging pile with built-in integrated direct current electric energy meter according to claim 1, characterized in that, The second DC contactor group includes a third contactor and a fourth contactor; one end of the third contactor is connected to the node of the positive bus located at the front end of the first contactor, and the other end is connected to the positive input terminal of the inverter module; one end of the fourth contactor is connected to the node of the negative bus located at the front end of the second contactor, and the other end is connected to the negative input terminal of the inverter module.

3. The direct current bidirectional charging pile with built-in integrated direct current electric energy meter according to claim 1, characterized in that, A DC fuse is also provided between the DC output terminal of the charging module and the first DC contactor group, and the DC fuse is connected in series on the positive bus.

4. The direct current bidirectional charging pile with built-in integrated direct current electric energy meter according to claim 1, characterized in that, The AC input circuit includes a surge protector and a circuit breaker connected in sequence; the surge protector is connected in parallel at the mains input terminal, and the circuit breaker is connected in series between the mains input terminal and the charging module.

5. The direct current bidirectional charging pile with built-in integrated direct current electric energy meter according to claim 2, characterized in that, It also includes an auxiliary power supply circuit and a control unit; the auxiliary power supply circuit includes a miniature leakage current switch and a switching power supply, the input terminal of the miniature leakage current switch is connected to the AC input circuit, and the output terminal is connected to the switching power supply, which is used to output low-voltage DC power; the control unit includes a main control unit, a billing control unit and an insulation monitoring unit, and the working power interface of the main control unit, the billing control unit, the insulation monitoring unit and the integrated DC energy meter are all connected to the output terminal of the switching power supply.

6. The direct current bidirectional charging pile with built-in integrated direct current electric energy meter according to claim 5, characterized in that, The control output terminal of the main control unit is connected to the coils of the first contactor, the second contactor, the third contactor, and the fourth contactor through a control circuit, and is used to control the engagement and disengagement of each contactor; the detection terminal of the insulation monitoring unit is connected to the DC high-voltage circuit at the rear end of the first DC contactor group.

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